Fitting and Comparing Galactic Foreground Models for Unbiased 21-cm Cosmology [CEA]

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http://arxiv.org/abs/2304.09959


Accurate detection of the cosmological 21-cm global signal requires galactic foreground models that can fit spectra down to $\sim 20$ mK or less, representing a removal of power over nearly six orders of magnitude. Rarely are such models tested to this level, let alone their dependence upon model inputs like sky temperature maps. We therefore test the ability of seven commonly employed foreground models — including nonlinear and linear forward-models, polynomials, and maximally-smooth polynomials — to fit realistic simulated mock spectra, as well as their dependence upon model inputs. The mock spectra are synthesized from intrinsic foregrounds with realistic spatial and spectral structure, chromatic beams, horizon profiles, and discrete time-sampling. For a single LST bin spectrum, the nonlinear-forward model with 4 parameters is preferred using a KS-test of the noise-normalized residuals, while the linear forward-model fits well with 6-7 parameters. The polynomials and maximally-smooth polynomials, like those employed by the EDGES and SARAS3 experiments, cannot produce good fits with 5 parameters. However, we find that polynomials with 6 parameters pass the KS-test, although a 9 parameter fit produces the highest p-value. When fitting multiple LST bins simultaneously to decrease overlap with global signal models, we find that the linear forward-model outperforms the nonlinear for 2, 5 and 10 LST bins. In addition, the nonlinear forward-model fails to produce good fits to spectra with 10 LST bins, in contrast to the linear. Importantly, the KS-test consistently identifies best-fit \textit{and} preferred models as opposed to the $\chi^2_{red}$ and Bayesian evidence, especially in cases involving nonlinear models.

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J. Hibbard, D. Rapetti, J. Burns, et. al.
Fri, 21 Apr 23
37/60

Comments: 25 pages, 12 figures, submitted to ApJ

Improved CMB (de-)lensing using general spherical harmonic transforms [CEA]

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http://arxiv.org/abs/2304.10431


Deep Cosmic Microwave Background polarization experiments allow in principle very precise internal reconstruction of the gravitational lensing signal. To this aim, likelihood-based or Bayesian methods are typically necessary, where performing a sometimes very large number of lensing and delensing remappings on the sphere is required before satisfactory convergence. We discuss here in some detail an optimized piece of numerical code able to perform both the lensing operation and its adjoint (closely related to delensing) efficiently, and to arbitrary accuracy, using non-uniform Fast Fourier Transform technology. Where applicable, we find the code outperforms by massive amounts current widespread software, being able to produce high-resolution maps accurate enough for next-generation CMB experiments on the timescale of seconds on a modern laptop. The adjoint operation performs similarly, and removes the need for computation of inverse deflection fields. This publicly available code enables de facto efficient spherical harmonic transforms on completely arbitrary grids, and could possibly find applications also in other areas.

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M. Reinecke, S. Belkner and J. Carron
Fri, 21 Apr 23
38/60

Comments: 7 pages, 3 figures, prepared for A&A submission

Fading AGN in Post-Starburst Galaxies [GA]

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http://arxiv.org/abs/2304.10419


The role of AGN in quenching galaxies and driving the evolution from star-forming to quiescent remains a key question in galaxy evolution. We present evidence from the Mapping Nearby Galaxies at APO (MaNGA) survey for fading AGN activity in 6/93 post-starburst galaxies. These six galaxies show extended emission line regions (EELRs) consistent with ionization from past AGN activity, analogous to “Hanny’s voorwerp” and other systems where the OIII5007 emission is bright enough to be visible in broadband imaging. Using the infrared luminosities from IRAS to estimate the current AGN luminosity, we find that 5/6 of the post-starburst galaxies have current AGN which have faded from the peak luminosity required to have ionized the EELRs. Given the rate at which we observe EELRs, the typical EELR visibility timescale, and an estimate of how often EELRs would be visible, we estimate the duty cycle of AGN activity during the post-starburst phase. The timescale for the galaxy to cycle between peaks in AGN luminosity is $t_{\rm EELR}\sim1.1-2.3\times10^5$ yr. Given the rate at which we observe current AGN activity during this phase, we estimate that the AGN spends only 5.3% of this time (or $t_{\rm ON} = 0.6-1.3\times10^4$ yr) in its luminous phase, with the rest of the time spent “off” or in a low-luminosity phase. The length of this duty cycle may explain why so few luminous AGN have been observed during the post-starburst phase, despite evidence for AGN feedback at work.

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K. French, N. Earl, A. Novack, et. al.
Fri, 21 Apr 23
39/60

Comments: Re-submitted to ApJ after referee report. 20 pages, 13 figures

Early-time spectroscopic modelling of the transitional Type Ia Supernova 2021rhu with TARDIS [HEAP]

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http://arxiv.org/abs/2304.10129


An open question in SN Ia research is where the boundary lies between ‘normal’ Type Ia supernovae (SNe Ia) that are used in cosmological measurements and those that sit off the Phillips relation. We present the spectroscopic modelling of one such ’86G-like’ transitional SN Ia, SN 2021rhu, that has recently been employed as a local Hubble Constant calibrator using a tip of the red-giant branch measurement. We detail its modelling from -12 d until maximum brightness using the radiative-transfer spectral-synthesis code tardis. We base our modelling on literature delayed-detonation and deflagration models of Chandrasekhar mass white dwarfs, as well as the double-detonation models of sub-Chandrasekhar mass white dwarfs. We present a new method for ‘projecting’ abundance profiles to different density profiles for ease of computation. Due to the small velocity extent and low outer densities of the W7 profile, we find it inadequate to reproduce the evolution of SN 2021rhu as it fails to match the high-velocity calcium components. The host extinction of SN 2021rhu is uncertain but we use modelling with and without an extinction correction to set lower and upper limits on the abundances of individual species. Comparing these limits to literature models we conclude that the spectral evolution of SN 2021rhu is also incompatible with double-detonation scenarios, lying more in line with those resulting from the delayed detonation mechanism (although there are some discrepancies, in particular a larger titanium abundance in SN 2021rhu compared to the literature). This suggests that SN 2021rhu is likely a lower luminosity, and hence lower temperature, version of a normal SN Ia.

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L. Harvey, K. Maguire, M. Magee, et. al.
Fri, 21 Apr 23
40/60

Comments: Comments: 25 pages, 22 figures, accepted for publication in MNRAS

Localization of binary neutron star mergers with a single Cosmic Explorer [HEAP]

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http://arxiv.org/abs/2304.09889


Next-generation ground-based gravitational-wave detectors, such as Cosmic Explorer (CE), are expected to be sensitive to gravitational-wave signals with frequencies as low as 5 Hz, allowing signals to spend a significant amount of time in the detector frequency band. As a result, the effects caused by the rotation of the Earth become increasingly important for such signals. Additionally, the length of the arms of these detectors can be comparable to the wavelength of detectable gravitational waves, which introduces frequency-dependent effects that are not significant in current-generation detectors. These effects are expected to improve the ability to localize compact binary coalescences in the sky even when using only one detector. This study aims to understand how much these effects can help in localization. We present the first comprehensive Bayesian parameter estimation framework that accounts for all these effects using \textsc{Bilby}, a commonly used Bayesian parameter estimation tool. We focus on sky localization constraints for binary neutron star events with an optimal signal-to-noise ratio of 1000 with one detector at the projected CE sensitivity. We find that these effects help localize sources using one detector with sky areas as low as 10 square degrees. Moreover, we explore and discuss how ignoring these effects in the parameter estimation can lead to biases in the inference.

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P. Baral, S. Morisaki, I. Hernandez, et. al.
Fri, 21 Apr 23
41/60

Comments: N/A

A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): JWST Reveals a Filamentary Structure around a z=6.61 Quasar [GA]

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http://arxiv.org/abs/2304.09894


We present the first results from the JWST ASPIRE program (A SPectroscopic survey of biased halos In the Reionization Era). This program represents an imaging and spectroscopic survey of 25 reionization-era quasars and their environments by utilizing the unprecedented capabilities of NIRCam Wide Field Slitless Spectroscopy (WFSS) mode. ASPIRE will deliver the largest ($\sim280~{\rm arcmin}^2$) galaxy redshift survey at 3-4 $\mu$m among JWST Cycle-1 programs and provide extensive legacy values for studying the formation of the earliest supermassive black holes (SMBHs), the assembly of galaxies, early metal enrichment, and cosmic reionization. In this first ASPIRE paper, we report the discovery of a filamentary structure traced by the luminous quasar J0305-3150 and ten [OIII] emitters at $z=6.6$. This structure has a 3D galaxy overdensity of $\delta_{\rm gal}=12.6$ over 637 cMpc$^3$, one of the most overdense structures known in the early universe, and could eventually evolve into a massive galaxy cluster. Together with existing VLT/MUSE and ALMA observations of this field, our JWST observations reveal that J0305-3150 traces a complex environment where both UV-bright and dusty galaxies are present, and indicate that the early evolution of galaxies around the quasar is not simultaneous. In addition, we discovered 31 [OIII] emitters in this field at other redshifts, $5.3<z<6.7$, with half of them situated at $z\sim5.4$ and $z\sim6.2$. This indicates that star-forming galaxies, such as [OIII] emitters, are generally clustered at high redshifts. These discoveries demonstrate the unparalleled redshift survey capabilities of NIRCam WFSS and the potential of the full ASPIRE survey dataset.

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F. Wang, J. Yang, J. Hennawi, et. al.
Fri, 21 Apr 23
42/60

Comments: accepted for publication in ApJL

Probing primordial black holes from a first order phase transition through pulsar timing and gravitational wave signals [CL]

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http://arxiv.org/abs/2304.10084


In this work, we assess the sensitivity reach of pulsar timing array (PTA) measurements to probe pointlike primordial black holes (PBHs), with an extended mass distribution, which originate from collapsed Fermi balls that are formed through the aggregation of asymmetric U(1) dark fermions trapped within false vacuum bubbles during a dark first order phase transition (FOPT). The PBH formation scenario is mainly characterized by the dark asymmetry, strength of the FOPT, rate of FOPT, and the percolation temperature. Meanwhile, for PBH masses of interest lying within $10^{-10} M_\odot – 10^{-3}M_\odot$, the relevant signal for PTA measurements is the Doppler phase shift in the timing signal, due to the velocity change induced by transiting PBHs on pulsars. Taking the dark asymmetry parameter to be $10^{-4}$ and $10^{-5}$, we find that percolation temperatures within the 0.1-10 keV range, FOPT rates above $10^3$ times the Hubble parameter at percolation, and FOPT strengths within $10^{-6}-0.1$ can give rise to PBHs that can be probed by an SKA-like PTA observation. On the other hand, the accompanying gravitational wave (GW) signal from the FOPT can be used as a complementary probe, assuming that the peak frequency lies within the $\mathcal{O}(10^{-9})-\mathcal{O}(10^{-6})$ Hz range, and the peak GW abundance is above the peak-integrated sensitivity curves associated with pulsar timing observations that search for stochastic GWs. At the fundamental level, a quartic effective potential for a dark scalar field can trigger the FOPT. By performing a parameter scan, we obtained the class of effective potentials that lead to FOPT scenarios that can be probed by SKA through pulsar timing and GW observations.

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J. Acuña and P. Tseng
Fri, 21 Apr 23
43/60

Comments: 40 pages, 8 figures

The Challenge of Eccentricity when Observing Stellar-mass Binary Black Holes with Space-Based Gravitational Wave Detectors [HEAP]

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http://arxiv.org/abs/2304.10340


Eccentricity is a smoking gun for the formation channel of stellar-mass binary black holes (sBBHs). Space-based gravitational wave observatories can determine binary eccentricity to $e_0\gtrsim\mathcal{O}(10^{-4}) $, but the detection of these systems can be very challenging. A targeted search of archival data triggered by ground-based detectors shrinks the search range thus making the task tractable. Previous studies ignored the effect of eccentricity. For the first time, we constructed a template bank for space-borne gravitational wave detectors that includes the impact of eccentricity. We find that even for a mild upper limit of $0.1$, the inclusion of eccentricity can still boost the template bank size by five orders of magnitudes. Our work marked a solid step towards the detection of a realistic sBBH, and it demonstrated that with the appropriate extension, the template bank method can still identify the early inspiral of sBBHs.

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H. Wang, I. Harry, A. Nitz, et. al.
Fri, 21 Apr 23
44/60

Comments: 7 pages, 3 figures, comments welcome

Jupiter Science Enabled by ESA's Jupiter Icy Moons Explorer [EPA]

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http://arxiv.org/abs/2304.10229


ESA’s Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 $\mu$m), and sub-millimetre sounding (near 530-625\,GHz and 1067-1275\,GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet.

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L. Fletcher, T. Cavalié, D. Grassi, et. al.
Fri, 21 Apr 23
45/60

Comments: 83 pages, 24 figures, submitted to Space Science Reviews special issue on ESA’s JUICE mission

The Launching of Cold Clouds by Galaxy Outflows V:The Role of Anisotropic Thermal Conduction [GA]

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http://arxiv.org/abs/2304.09881


Motivated by observations of multiphase galaxy outflows, we explore the impact of isotropic and anisotropic electron thermal conduction on the evolution of radiatively-cooled, cold clouds embedded in hot, magnetized winds. Using the adaptive mesh refinement code AthenaPK, we conduct simulations of clouds impacted by supersonic and transonic flows with magnetic fields initially aligned parallel and perpendicular to the flow direction. In cases with isotropic thermal conduction, an evaporative wind forms, stabilizing against instabilities and leading to a mass loss rate that matches the hydrodynamic case. In anisotropic cases, the impact of conduction is more limited and strongly dependent on the field orientation. In runs with initially transverse fields, the field lines are folded back into the tail, strongly limiting conduction, but magnetic fields act to dampen instabilities and slow the stretching of the cloud in the flow direction. In the aligned case, anisotropic conduction aids cloud survival by forming a radiative wind near the front of the cloud, which suppresses instabilities with minimal mass loss. In all cases, anisotropic conduction has a minimal impact on the acceleration of the cloud.

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M. Brüggen, E. Scannapieco and P. Grete
Fri, 21 Apr 23
46/60

Comments: submitted to ApJ

Halo assembly bias from a deep learning model of halo formation [CEA]

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http://arxiv.org/abs/2304.09880


We build a deep learning framework that connects the local formation process of dark matter halos to the halo bias. We train a convolutional neural network (CNN) to predict the final mass and concentration of dark matter halos from the initial conditions. The CNN is then used as a surrogate model to derive the response of the halos’ mass and concentration to long-wavelength perturbations in the initial conditions, and consequently the halo bias parameters following the “response bias” definition. The CNN correctly predicts how the local properties of dark matter halos respond to changes in the large-scale environment, despite no explicit knowledge of halo bias being provided during training. We show that the CNN recovers the known trends for the linear and second-order density bias parameters $b_1$ and $b_2$, as well as for the local primordial non-Gaussianity linear bias parameter $b_\phi$. The expected secondary assembly bias dependence on halo concentration is also recovered by the CNN: at fixed mass, halo concentration has only a mild impact on $b_1$, but a strong impact on $b_\phi$. Our framework opens a new window for discovering which physical aspects of the halo’s Lagrangian patch determine assembly bias, which in turn can inform physical models of halo formation and bias.

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L. Lucie-Smith, A. Barreira and F. Schmidt
Fri, 21 Apr 23
47/60

Comments: 11 pages, 5 figures, to be submitted to MNRAS, comments welcome

3D hydrodynamic simulations of massive main-sequence stars. III. The effect of radiation pressure and diffusion leading to a 1D equilibrium model [SSA]

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http://arxiv.org/abs/2304.10470


We present 3D hydrodynamical simulations of core convection with a stably stratified envelope of a 25 $\mathrm{M}_\odot$ star in the early phase of the main-sequence. We use the explicit gas-dynamics code $\texttt{PPMstar}$ which tracks two fluids and includes radiation pressure and radiative diffusion. Multiple series of simulations with different luminosities and radiative thermal conductivities are presented. The entrainment rate at the convective boundary, internal gravity waves in and above the boundary region, and the approach to dynamical equilibrium shortly after a few convective turnovers are investigated. From the results of these simulations we extrapolate to find the entrainment rate at the nominal heating rate and thermal diffusion given by the $\texttt{MESA}$ stellar evolution model on which the 3D stratification is based. Further, to study the effect of radiative diffusion on the thermal timescale, we perform very long simulations accelerated by 10000 times their nominal luminosities. In these simulations the growing penetrative convection reduces the initially unrealistically large entrainment. This reduction is enabled by a spatial separation that develops between the entropy gradient and the composition gradient. The convective boundary moves outward much more slowly at the end of these simulations. Finally, we present a method to predict the extent and character of penetrative convection beyond the Schwarzschild boundary. This method is intended to be ultimately deployed in 1D stellar evolution calculations and is based on the properties of penetrative convection in our simulations carried forward through the local thermal timescale.

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H. Mao, P. Woodward, F. Herwig, et. al.
Fri, 21 Apr 23
48/60

Comments: 33 pages, 31 figures; submitted to ApJ

Accurate Oxygen Abundance of Interstellar Gas in Mrk 71 from Optical and Infrared Spectra [GA]

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http://arxiv.org/abs/2304.09898


The heavy element content (“metallicity”) of the Universe is a record of the total star formation history. Gas-phase metallicity in galaxies, as well as its evolution with time, is of particular interest as a tracer of accretion and outflow processes. However, metallicities from the widely-used electron temperature ($T_e$) method are typically ~2x lower than the values based on the recombination line method. This “abundance discrepancy factor” (ADF) is well known and is commonly ascribed to bias due to temperature fluctuations. We present a measurement of oxygen abundance in the nearby (3.4 Mpc) system, Mrk 71, using a combination of optical and far-IR emission lines to measure and correct for temperature fluctuation effects. Our far-IR result is inconsistent ($> 2 \sigma$ significance) with the metallicity from recombination lines and instead indicates little to no bias in the standard $T_e$ method, ruling out the long-standing hypothesis that the ADF is explained by temperature fluctuations for this object. Our results provide a framework to accurately measure metallicity across cosmic history, including with recent data reaching within the first billion years with JWST and the Atacama Large Millimeter Array (ALMA).

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Y. Chen, T. Jones, R. Sanders, et. al.
Fri, 21 Apr 23
49/60

Comments: 26 pages, 7 figures. Accepted for publication

Compact Steep Spectrum Radio Sources with Enhanced Star Formation are Smaller than $10\,$kpc [GA]

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http://arxiv.org/abs/2304.10538


Compact Steep Spectrum (CSS) radio sources are active galactic nuclei that have radio jets propagating only on galactic scales, defined as having projected linear sizes (LS) of up to $20\,$kpc. CSS sources are generally hosted by massive early-type galaxies with little on-going star formation, however a small fraction are known to have enhanced star formation. Using archival data from the Faint Images of the Radio Sky at Twenty cm survey, the Very Large Array Sky Survey and the Sloan Digital Sky Survey we identify a volume-limited sample of $166$ CSS sources at $z<0.2$ with $L_{1.4\,\text{GHz}}>10^{24}\,\text{W}\,\text{Hz}^{-1}$. Comparing the star formation rates and linear sizes of these CSS sources, we find that the $\approx14\,\%$ of CSS sources with specific star formation rates above $0.01\,\text{Gyr}^{-1}$ all have $\text{LS}<10\,$kpc. We discuss the possible mechanisms driving this result, concluding that it is likely the excess star formation in these sources occurred in multiple bursts and ceased prior to the AGN jet being triggered.

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Y. Gordon, C. O’Dea, S. Baum, et. al.
Fri, 21 Apr 23
50/60

Comments: Accepted for publication in ApJL. 9 pages, 5 figures

Hard TeV Gamma-Ray Afterglows of Nearby GRB 190829A as a Tentative Signature of Ultra-High-Energy Cosmic Rays Accelerated in Gamma-Ray Burst Jets [HEAP]

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http://arxiv.org/abs/2304.10188


The observed hard TeV gamma-ray spectrum of the nearby gamma-ray burst (GRB) 190829A may challenge the conventional leptonic GRB afterglow model. It has been proposed that an ultra-high-energy (UHE; $\varepsilon^{‘}{\rm p}\sim 10^{20}$ eV) proton population can be pre-accelerated by internal shocks in GRB jets. We study possible signatures of the UHE protons embedded in the TeV afterglows when they escape the afterglow fireball. We show that the leptonic model can represent the observed multiwavelength lightcurves and spectral energy distributions of GRB 190829A by considering the uncertainties of the model parameters. Attributing the TeV gamma-ray afterglows to the emission of both the electron self-Compton scattering process and the UHE proton synchrotron radiations in the afterglow fireball, we obtain tentative upper limits of $\log{10} \varepsilon_{\rm p}^{\prime}/{\rm eV}\sim 20.46$ and $\log_{10}E_{\rm p, total}/{\rm erg}\leq 50.75$, where $E_{\rm p, total}$ is the total energy of the proton population. The synchrotron radiations of the UHE protons should dominate the early TeV gamma-ray afterglows, implying that early observations are critical for revealing the UHE proton population.

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J. Huang, X. Huang, J. Cheng, et. al.
Fri, 21 Apr 23
51/60

Comments: 9 pages, 4 figures, Accepted for Publication in ApJ

The Chemodynamics of the Stellar Populations in M31 from APOGEE Integrated Light Spectroscopy [GA]

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http://arxiv.org/abs/2304.09901


We present analysis of nearly 1,000 near-infrared, integrated light spectra from APOGEE in the inner $\sim$7 kpc of M31. We utilize full spectrum fitting with A-LIST simple stellar population spectral templates that represent a population of stars with the same age, [M/H], and [$\alpha$/M]. With this, we determine the mean kinematics, metallicities, $\alpha$ abundances, and ages of the stellar populations of M31’s bar, bulge, and inner disk ($\sim$4-7 kpc). We find a non-axisymmetric velocity field in M31 resulting from the presence of a bar. The bulge of M31 is metal-poor relative to the disk ([M/H] = $-0.149^{+0.067}{-0.081}$ dex), features minima in metallicity on either side of the bar ([M/H] $\sim$ -0.2), and is enhanced in $\alpha$ abundance ([$\alpha$/M] = $0.281^{+0.035}{-0.038}$). The disk of M31 within $\sim$7 kpc is enhanced in both metallicity ([M/H] = $-0.023^{+0.050}{-0.052}$) and $\alpha$ abundance ([$\alpha$/M] = $0.274^{+0.020}{-0.025}$). Both of these structural components are uniformly old at $\simeq$ 12 Gyr. We find the metallicity increases with distance from the center of M31, with the steepest gradient along the disk major axis ($0.043\pm0.021$ dex/kpc). This gradient is the result of changing light contributions from the metal-poor bulge and metal-rich disk. The chemodynamics of stellar populations encodes information about a galaxy’s chemical enrichment, star formation history, and merger history, allowing us to discuss new constraints on M31’s formation. Our results provide a stepping stone between our understanding of the Milky Way and other external galaxies.

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B. Gibson, G. Zasowski, A. Seth, et. al.
Fri, 21 Apr 23
52/60

Comments: N/A

The Nature of the Motions of Multiphase Filaments in the Centers of Galaxy Clusters [GA]

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http://arxiv.org/abs/2304.09879


The intracluster medium (ICM) in the centers of galaxy clusters is heavily influenced by the “feedback” from supermassive black holes (SMBHs). Feedback can drive turbulence in the ICM and turbulent dissipation can potentially be an important source of heating. Due to the limited spatial and spectral resolutions of X-ray telescopes, direct observations of turbulence in the hot ICM have been challenging. Recently, we developed a new method to measure turbulence in the ICM using multiphase filaments as tracers. These filaments are ubiquitous in cluster centers and can be observed at very high resolution using optical and radio telescopes. We study the kinematics of the filaments by measuring their velocity structure functions (VSFs) over a wide range of scales in the centers of $\sim 10$ galaxy clusters. We find features of the VSFs that correlate with the SMBHs activities, suggesting that SMBHs are the main driver of gas motions in the centers of galaxy clusters. In all systems, the VSF is steeper than the classical Kolmogorov expectation and the slopes vary from system to system. One theoretical explanation is that the VSFs we have measured so far mostly reflect the motion of the driver (jets and bubbles) rather than the cascade of turbulence. We show that in Abell 1795, the VSF of the outer filaments far from the SMBH flattens on small scales to a Kolmogorov slope, suggesting that the cascade is only detectable farther out with the current telescope resolution. The level of turbulent heating computed at small scales is typically an order of magnitude lower than that estimated at the driving scale. Even though SMBH feedback heavily influences the kinematics of the ICM in cluster centers, the level of turbulence it drives is rather low, and turbulent heating can only offset $\lesssim10\%$ of the cooling loss, consistent with the findings of numerical simulations.

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S. Ganguly, Y. Li, V. Olivares, et. al.
Fri, 21 Apr 23
53/60

Comments: 21 pages, 4 figures, accepted for publication in Frontiers in Astronomy and Space Sciences: Thermal Imbalance and Multiphase Plasmas Across Scales: From the Solar Corona to the Intracluster Medium

The Detection of a Compact Radio Feature in a Seyfert Galaxy After an Accretion Rate Change [GA]

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http://arxiv.org/abs/2304.10125


X-ray binaries are known to show state transitions related to accretion rate changes which are often accompanied with dramatic changes in the jet emission. However, it is not clear whether this characteristics of stellar-mass black hole systems can be scaled up to the accretion disk of active galactic nuclei. The Seyfert 1 galaxy, KUG 1141+371 has been showing a steadily increasing X-ray flux since 2007, and exhibited variability behaviour similar to the state transitions observed in X-ray binaries. It was hypothesised to undergo a rapid boost of mass accretion. If the X-ray binary analogy holds then the appearance of jet emission can also be expected in KUG 1141+371. While the source was not detected in the Faint Images of the Radio Sky at Twenty-centimeters in 1994, it appears in the VLA Sky Survey in 2019 and at 22 GHz in a VLA observation in 2018 at mJy flux density level. Our VLBI observations revealed a compact, flat-spectrum radio feature. Its high brightness temperature indicates the radio emission originates from an AGN.

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K. Gabányi, K. Smith, S. Frey, et. al.
Fri, 21 Apr 23
54/60

Comments: 5 pages, 2 figures; to appear in the proceedings of the 15th European VLBI Network Symposium and Users’ Meeting (EVN2022), 11-15 July 2022, University College Cork, Ireland

Testing the first law of black hole mechanics with gravitational waves [CL]

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http://arxiv.org/abs/2304.10117


GW191219_163120 is a gravitational wave signal that is believed to have originated from a neutron star-black hole (NSBH) coalescence with an extreme mass ratio. In this work, we use data of GW191219_163120 from LIGO and Virgo to test the first law of black hole mechanics by considering the neutron star as a perturbation to the black hole before the merger, and the remnant black hole as a stationary black hole after the merger. Our results demonstrate consistency with the first law of black hole mechanics, with an error level of about 6\% at 68\% credibility and 10\% at 95\% credibility. We also find that the higher the mass ratio of the gravitational wave source, the more consistent our results are with the first law of black hole mechanics. Overall, our study sheds light on the nature of NSBH coalescences and their implications for black hole mechanics.

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C. Wang and F. Shu
Fri, 21 Apr 23
55/60

Comments: 5 pages, 4 figures, 2 tables

Anomalies in Gravitational-Lensed Images Revealing Einstein Rings Modulated by Wavelike Dark Matter [CEA]

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http://arxiv.org/abs/2304.09895


Elucidating the nature of Dark Matter (DM), which does not interact with light and which interacts with known matter primarily or only through gravity, is one of the principal quests in physics. Leading candidates for DM are weakly interacting massive particles (WIMPs) or ultralight bosons (axions), at opposite extremes in mass scales, that have been postulated by competing theories to solve deficiencies in the Standard Model of particle physics. Whereas DM WIMPs behave like discrete particles ($\varrho$DM), quantum interference between DM axions is manifested as waves ($\psi$DM). Here, we show that gravitational lensing leaves signatures in multiply-lensed images of background galaxies that reveal whether the foreground lensing galaxy inhabits a $\varrho$DM or $\psi$DM halo. Whereas $\varrho$DM lens models leave well documented anomalies between the predicted and observed brightnesses and positions of multiply-lensed images, $\psi$DM lens models correctly predict the level of anomalies left over by $\varrho$DM lens models. More challengingly, when subjected to a battery of tests for reproducing the quadruply-lensed triplet images in the system HS 0810+2554, $\psi$DM is able to reproduce all aspects of this system whereas $\varrho$DM often fails. The growing success of $\psi$DM in reproducing astrophysical observations tilt the balance toward new physics invoking axions.

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A. Amruth, T. Broadhurst, J. Lim, et. al.
Fri, 21 Apr 23
56/60

Comments: This preprint has not undergone peer review or any post-submission improvements or corrections. The Version of Record of this article is published in Nature Astronomy, and is available online at this https URL or this https URL Please check out the final version on Nature Astronomy’s website for the improved main text

A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of $z > 6.5$ Quasars Using JWST [GA]

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http://arxiv.org/abs/2304.09888


Studies of rest-frame optical emission in quasars at $z>6$ have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations of eight quasars at $z>6.5$ using the JWST/NIRCam Wide Field Slitless Spectroscopy, as a part of the ”A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE)” program. Our JWST spectra cover the quasars’ emission between rest frame $\sim$ 4100 and 5100 \r{A}. The profiles of these quasars’ broad H$\beta$ emission lines span a FWHM from 3000 to 6000 $\rm{km~s^{-1}}$. The H$\beta$-based virial black hole (BH) masses, ranging from 0.6 to 2.1 billion solar masses, are generally consistent with their MgII-based BH masses. The new measurements based on the more reliable H$\beta$ tracer thus confirm the existence of billion solar-mass BHs in the reionization epoch. In the observed [OIII] $\lambda\lambda$4960,5008 doublets of these luminous quasars, broad components are more common than narrow core components ($\le~1200~\rm{km~s^{-1}}$), and only one quasar shows stronger narrow components than broad. Two quasars exhibit significantly broad and blueshifted [OIII] emission, thought to trace galactic-scale outflows, with median velocities of $-610~\rm{km~s^{-1}}$ and $-1430~\rm{km~s^{-1}}$ relative to the [CII] $158\,\mu$m line. All eight quasars show strong optical FeII emission, and follow the Eigenvector 1 relations defined by low-redshift quasars. The entire ASPIRE program will eventually cover 25 quasars and provide a statistical sample for the studies of the BHs and quasar spectral properties.

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J. Yang, F. Wang, X. Fan, et. al.
Fri, 21 Apr 23
57/60

Comments: 13 pages, 4 figures, accepted for publication in ApJL

Accurate mass-radius ratios for Hyades white dwarfs [SSA]

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http://arxiv.org/abs/2304.10485


We use the ESPRESSO spectrograph at the Very Large Telescope to measure velocity shifts and gravitational redshifts of eight bona fide Hyades white dwarfs, with an accuracy better than 1.5 percent. By comparing the gravitational redshift measurements of the mass-to-radius ratio with the same ratios derived by fitting the \textit{Gaia} photometry with theoretical models, we find an agreement to better than one per cent. It is possible to reproduce the observed white dwarf cooling sequence and the trend of the mass-to-radius ratios as a function of colour using isochrones with ages between 725 and 800 Myr, tuned for the Hyades. One star, EGGR\,29, consistently stands out in all diagrams, indicating that it is possibly the remnant of a blue straggler. We also computed mass-to-radius ratios from published gravities and masses, determined from spectroscopy. The comparison between photometric and spectroscopic stellar parameters reveals that spectroscopic effective temperature and gravity are systematically larger than the photometric values. Spectroscopic mass-to-radius ratios disagree with those measured from gravitational redshift, indicating the presence of systematics affecting the white dwarf parameters derived from the spectroscopic analysis.

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L. Pasquini, A. Pala, M. Salaris, et. al.
Fri, 21 Apr 23
58/60

Comments: MNRAS, accepted for pubblication

Annotated bibliography: Philosophy of Astrophysics [CL]

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http://arxiv.org/abs/2304.10067


The following annotated bibliography contains a reasonably complete survey of contemporary work in the philosophy of astrophysics. Spanning approximately forty years from the early 1980s to the present day, the bibliography should help researchers entering the field to acquaint themselves with its major texts, while providing an opportunity for philosophers already working on astrophysics to expand their knowledge base and engage with unfamiliar material.

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C. Yetman
Fri, 21 Apr 23
59/60

Comments: 28 pages, 79 entries, forthcoming 2023

Anisotropic Satellite Galaxy Quenching: A Unique Signature of Energetic Feedback by Supermassive Black Holes? [GA]

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http://arxiv.org/abs/2304.10403


The quenched fraction of satellite galaxies is aligned with the orientation of the halo’s central galaxy, such that on average, satellites form stars at a lower rate along the major axis of the central. This effect, called anisotropic satellite galaxy quenching (ASGQ), has been found in observational data and cosmological simulations. Analyzing the IllustrisTNG simulation, Mart\’in-Navarro et al. (2021) recently argued that ASGQ is caused by anisotropic energetic feedback and constitutes “compelling observational evidence for the role of black holes in regulating galaxy evolution.” In this letter, we study the causes of ASGQ in state-of-the-art galaxy formation simulations to evaluate this claim. We show that cosmological simulations predict that on average, satellite galaxies along the major axis of the dark matter halo tend to have been accreted at earlier cosmic times and are hosted by subhalos of larger peak halo masses. As a result, a modulation of the quenched fraction with respect to the major axis of the central galaxy is a natural prediction of hierarchical structure formation. We show that ASGQ is predicted by the UniverseMachine galaxy formation model, a model without anisotropic feedback. Furthermore, we demonstrate that even in the IllustrisTNG simulation, anisotropic satellite accretion properties are the main cause of ASGQ. Ultimately, we argue that ASGQ is not a reliable indicator of supermassive black hole feedback in galaxy formation simulations and, thus, should not be interpreted as such in observational data.

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J. Karp, J. Lange and R. Wechsler
Fri, 21 Apr 23
60/60

Comments: 7 pages, 4 figures; Submitted to ApJL; Comments welcome!

Exploring the impact of IMF and binary parameter stochasticity with a binary population synthesis code [GA]

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http://arxiv.org/abs/2304.09549


Low mass star formation regions are unlikely to fully populate their initial mass functions, leading to a deficit of massive stars. In binary stellar populations, the full range of binary separations and mass ratios will also be underpopulated. To explore the effects of stochastic sampling in the integrated light of stellar clusters, we calculate models at a broad range of cluster masses, from 10^2 to 10^7 M_sun, using a binary stellar population synthesis code. For clusters with stellar masses less than 10^5 M_sun, observable quantities show substantial scatter and their mean properties reflect the expected deficit of massive stars. In common with previous work, we find that purely stochastic sampling of the initial mass function appears to underestimate the mass of the most massive star in known clusters. However, even with this constraint, the majority of clusters likely inject sufficient kinetic energy to clear their birth clusters of gas. For quantities which directly measure the impact of the most massive stars, such as N_{ion}, xi_{ion} and beta_{UV}, uncertainties due to stochastic sampling dominate over those from the IMF shape or distribution of binary parameters, while stochastic sampling has a negligible effect on the stellar continuum luminosity density.

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E. Stanway and J. Eldridge
Thu, 20 Apr 23
1/57

Comments: 15 pages and 8 page appendix. Accepted for publication in MNRAS

Constellations of co-orbital planets: horseshoe dynamics, long-term stability, transit timing variations, and potential as SETI beacons [EPA]

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http://arxiv.org/abs/2304.09209


Co-orbital systems contain two or more bodies sharing the same orbit around a planet or star. The best-known flavors of co-orbital systems are tadpoles (in which two bodies’ angular separations oscillate about the L4/L5 Lagrange points $60^\circ$ apart) and horseshoes (with two bodies periodically exchanging orbital energy to trace out a horseshoe shape in a co-rotating frame). Here, we use N-body simulations to explore the parameter space of many-planet horseshoe systems. We show that up to 24 equal-mass, Earth-mass planets can share the same orbit at 1 au, following a complex pattern in which neighboring planets undergo horseshoe oscillations. We explore the dynamics of horseshoe constellations, and show that they can remain stable for billions of years and even persist through their stars’ post-main sequence evolution. With sufficient observations, they can be identified through their large-amplitude, correlated transit timing variations. Given their longevity and exotic orbital architectures, horseshoe constellations may represent potential SETI beacons.

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S. Raymond, D. Veras, M. Clement, et. al.
Thu, 20 Apr 23
2/57

Comments: 10 pages, 10 figures. Published in MNRAS. YouTube playlist with animations of horseshoe constellation systems here: this https URL . Blog post here: this https URL

ASASSN-18aan revisited [SSA]

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http://arxiv.org/abs/2304.09829


The light curve of the cataclismic variable ASASSN-18aan is studied using recent observations of the MC589 Observatory, giving an orbital Period and Epoch fully consistent with the data obtained after the discovery flare in 2018. Archival data from ASASSN, ZTF and Gaia were used to check if its flares have a quasi-periodic behaviour. A recurrency time scale of about 11 months is found, confirming a previous tentative result using the historic plate archive of the Asiago Observatory. The next outbursts are expected by April 2023 and March 2024.

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R. Nesci, A. Vagnozzi and S. Valentini
Thu, 20 Apr 23
3/57

Comments: 7 pages, 2 figures, published on OEJV

Modeling Charge Cloud Dynamics in Cross Strip Semiconductor Detectors [IMA]

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http://arxiv.org/abs/2304.09713


When a $\gamma$-ray interacts in a semiconductor detector, the resulting electron-hole charge clouds drift towards their respective electrodes for signal collection. These charge clouds will expand over time due to both thermal diffusion and mutual electrostatic repulsion. Solutions to the resulting charge profiles are well understood for the limiting cases accounting for only diffusion and only repulsion, but the general solution including both effects can only be solved numerically. Previous attempts to model these effects have taken into account the broadening of the charge profile due to both effects, but have simplified the shape of the profile by assuming Gaussian distributions. However, the detailed charge profile can have important impacts on charge sharing in multi-electrode strip detectors. In this work, we derive an analytical approximation to the general solution, including both diffusion and repulsion, that closely replicates both the width and the detailed shape of the charge profiles. This analytical solution simplifies the modeling of charge clouds in semiconductor strip detectors.

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S. Boggs
Thu, 20 Apr 23
4/57

Comments: Accepted for publication in Nuclear Instruments and Methods in Physics Research A

The magnetic field and multiple planets of the young dwarf AU~Mic [SSA]

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http://arxiv.org/abs/2304.09642


In this paper we present an analysis of near-infrared spectropolarimetric and velocimetric data of the young M dwarf AU Mic, collected with SPIRou at the Canada-France-Hawaii telescope from 2019 to 2022, mostly within the SPIRou Legacy Survey. With these data, we study the large- and small-scale magnetic field of AU Mic, detected through the unpolarized and circularly-polarized Zeeman signatures of spectral lines. We find that both are modulated with the stellar rotation period (4.86 d), and evolve on a timescale of months under differential rotation and intrinsic variability. The small-scale field, estimated from the broadening of spectral lines, reaches $2.61\pm0.05$ kG. The large-scale field, inferred with Zeeman-Doppler imaging from Least-Squares Deconvolved profiles of circularly-polarized and unpolarized spectral lines, is mostly poloidal and axisymmetric, with an average intensity of $550\pm30$ G. We also find that surface differential rotation, as derived from the large-scale field, is $\simeq$30% weaker than that of the Sun. We detect the radial velocity (RV) signatures of transiting planets b and c, although dwarfed by activity, and put an upper limit on that of candidate planet d, putatively causing the transit-timing variations of b and c. We also report the detection of the RV signature of a new candidate planet (e) orbiting further out with a period of $33.39\pm0.10$ d, i.e., near the 4:1 resonance with b. The RV signature of e is detected at 6.5$\sigma$ while those of b and c show up at $\simeq$4$\sigma$, yielding masses of $10.2^{+3.9}{-2.7}$ and $14.2^{+4.8}{-3.5}$ Earth masses for b and c, and a minimum mass of $35.2^{+6.7}_{-5.4}$ Earth masses for e.

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D. JF, C. PI, F. B, et. al.
Thu, 20 Apr 23
5/57

Comments: MNRAS, in press (20 pages and 12 figures + 9 pages of supplementary material)

Survival and dynamics of rings of co-orbital planets under perturbations [EPA]

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http://arxiv.org/abs/2304.09210


In co-orbital planetary systems, two or more planets share the same orbit around their star. Here we test the dynamical stability of co-orbital rings of planets perturbed by outside forces. We test two setups: i) ‘stationary’ rings of planets that, when unperturbed, remain equally-spaced along their orbit; and ii) horseshoe constellation systems, in which planets are continually undergoing horseshoe librations with their immediate neighbors. We show that a single rogue planet crossing the planets’ orbit more massive than a few lunar masses (0.01-0.04 Earth masses) systematically disrupts a co-orbital ring of 6, 9, 18, or 42 Earth-mass planets located at 1 au. Stationary rings are more resistant to perturbations than horseshoe constellations, yet when perturbed they can transform into stable horseshoe constellation systems. Given sufficient time, any co-orbital ring system will be perturbed into either becoming a horseshoe constellation or complete destabilization.

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S. Raymond, D. Veras, M. Clement, et. al.
Thu, 20 Apr 23
6/57

Comments: 5 pages, 4 figures. Re-submitted to MNRAS. Blog post about co-orbital constellations here: this https URL

Towards Accurate Field-Level Inference of Massive Cosmic Structures [CEA]

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http://arxiv.org/abs/2304.09193


We investigate the accuracy requirements for field-level inference of cluster masses and void sizes using data from galaxy surveys. We introduce a two-step framework that takes advantage of the fact that cluster masses are determined by flows on larger scales than the clusters themselves. First, we determine the integration accuracy required to perform field-level inference of cosmic initial conditions on these large scales, by fitting to late-time galaxy counts using the Bayesian Origin Reconstruction from Galaxies (BORG) algorithm. A 20-step COLA integrator is able to accurately describe the density field surrounding the most massive clusters in the Local Super-Volume ($<135\,h^{-1}\mathrm{Mpc}$), but does not by itself lead to converged virial mass estimates. Therefore we carry out `posterior resimulations’, using full $N$-body dynamics while sampling from the inferred initial conditions, and thereby obtain estimates of masses for nearby massive clusters. We show that these are in broad agreement with existing estimates, and find that mass functions in the Local Super-Volume are compatible with $\Lambda$CDM.

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S. Stopyra, H. Peiris, A. Pontzen, et. al.
Thu, 20 Apr 23
7/57

Comments: 12 pages, 6 figures

Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095 [EPA]

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http://arxiv.org/abs/2304.09220


The main scientific goal of TESS is to find planets smaller than Neptune around stars bright enough to allow further characterization studies. Given our current instrumentation and detection biases, M dwarfs are prime targets to search for small planets that are in (or nearby) the habitable zone of their host star. Here we use photometric observations and CARMENES radial velocity measurements to validate a pair of transiting planet candidates found by TESS. The data was fitted simultaneously using a Bayesian MCMC procedure taking into account the stellar variability present in the photometric and spectroscopic time series. We confirm the planetary origin of the two transiting candidates orbiting around TOI-2095 (TIC 235678745). The star is a nearby M dwarf ($d = 41.90 \pm 0.03$ pc, $T_{\rm eff} = 3759 \pm 87$ K, $V = 12.6$ mag) with a stellar mass and radius of $M_\star = 0.44 \pm 0.02 \; M_\odot$ and $R_\star = 0.44 \pm 0.02 \; R_\odot$, respectively. The planetary system is composed of two transiting planets: TOI-2095b with an orbital period of $P_b = 17.66484 \pm (7\times 10^{-5})$ days and TOI-2095c with $P_c = 28.17232 \pm (14\times 10^{-5})$ days. Both planets have similar sizes with $R_b = 1.25 \pm 0.07 \; R_\oplus$ and $R_c = 1.33 \pm 0.08 \; R_\oplus$ for planet b and c, respectively. We put upper limits on the masses of these objects with $M_b < 4.1 \; M_\oplus$ for the inner and $M_c < 7.4 \; M_\oplus$ for the outer planet (95\% confidence level). These two planets present equilibrium temperatures in the range of 300 – 350 K and are close to the inner edge of the habitable zone of their star.

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F. Murgas, A. Castro-González, E. Pallé, et. al.
Thu, 20 Apr 23
8/57

Comments: Submitted to Astronomy & Astrophysics

The quest for Magrathea planets I: formation of second generation exoplanets around double white dwarfs [EPA]

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http://arxiv.org/abs/2304.09204


The evolution of binaries that become double white dwarf (DWD) can cause the ejection of high amounts of dust and gas. Such material can give rise to circumbinary discs and become the cradle of new planets, yet no studies so far have focused on the formation of circumbinary planets around DWDs. These binaries will be the main sources of gravitational waves (GWs) detectable by the ESA Laser Interferometer Space Antenna (LISA) mission, opening the possibility to detect circumbinary planets around short-period DWDs everywhere in the Milky Way. We investigate the formation of Magrathea planets by simulating multiple planet formation tracks to explore how seeds growing first by pebble accretion, and then by gas accretion, are affected by the disc environments surrounding DWDs. We present both planetary formation tracks taking place in steady-state discs, and formation tracks taking place in discs evolving with time. The time-dependent tracks account for both the disc accretion rate onto the central binary and the disc photoevaporation rate caused by stellar irradiation. Our results show that planetary formation in circumbinary discs around DWDs can be possible. In particular, the extreme planetary formation environment implies three main significant results: (i) the accretion rate and the metallicity of the disc should be high in order to form sub-stellar objects with masses up to 31 M$J$, this is achieved only if planet formation starts soon after the onset of the disc and if first generation seeds are present in the disc; (ii) seeds formed within 0.1 Myr, or within 1 Myr, from the onset of the disc can only produce sub-Neptune and Neptunian planets, unless the disc accommodates first generation seeds with mass 10 M${\oplus}$; (iii) most of the planets are finally located within 1 au from the disc centre, while they are still undergoing the gas accretion phase.

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S. Ledda, C. Danielski and D. Turrini
Thu, 20 Apr 23
9/57

Comments: Accepted for publication in A&A on 05/04/2023, abstract shortened, 28 pages, 11 figures, 14 tables

Warm dark Matter constraints from the joint analysis of CMB, Lyman-α, and global 21 cm data [CEA]

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http://arxiv.org/abs/2304.09810


With the help of our previously built MCMC-based parameter estimation package \texttt{CosmoReionMC}, we investigate in detail the potential of 21~cm global signal, when combined with CMB and observations related to the QSO absorption spectra, to constraint the mass of Warm Dark Matter (WDM) particle. For the first time, we simultaneously vary all the free parameters (mass of WDM particle, cosmological parameters, and astrophysical parameters) to address the long-overlooked issue of the possible degeneracies between the Dark Matter particle mass $m_X$ and cosmological/astrophysical parameters. From the existing CMB and QSO absorption spectra data, we can rule out $m_X < 2.8$~keV at 95\% confidence level. Including the mock 21~cm global signal data expected in the future, the forecasted constraint is found to be much tighter $m_X > 7.7$~keV, assuming that the true dark matter model is the usual cold dark matter. In case the mock 21~cm signal is constructed for dark matter particles having $m_X = 7$~keV, our forecasts indicate that $\left(m_X / \text{keV}\right)^{-1}$ is in the range $[0.1, 0.2]$ ($95\%$ confidence level). This implies that the future 21~cm data should allow detection of the WDM particle mass if $m_X \sim 7$~keV

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A. Chatterjee and T. Choudhury
Thu, 20 Apr 23
10/57

Comments: Submitted to MNRAS

Universality of Bose-Einstein Condensation and Quenched Formation Dynamics [CL]

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http://arxiv.org/abs/2304.09541


The emergence of macroscopic coherence in a many-body quantum system is a ubiquitous phenomenon across different physical systems and scales. This Chapter reviews key concepts characterizing such systems (correlation functions, condensation, quasi-condensation) and applies them to the study of emerging non-equilibrium features in the dynamical path towards such a highly-coherent state: particular emphasis is placed on emerging universal features in the dynamics of conservative and open quantum systems, their equilibrium or non-equilibrium nature, and the extent that these can be observed in current experiments with quantum gases. Characteristic examples include symmetry-breaking in the Kibble-Zurek mechanism, coarsening and phase-ordering kinetics, and universal spatiotemporal scalings around non-thermal fixed points and in the context of the Kardar- Parisi-Zhang equation; the Chapter concludes with a brief review of the potential relevance of some of these concepts in modelling the large-scale distribution of dark matter in the universe.

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N. Proukakis
Thu, 20 Apr 23
11/57

Comments: Invited contribution to the Encyclopedia of Condensed Matter Physics (Elsevier, 2nd Edition)

Comment on "Observational Evidence for Cosmological Coupling of Black Holes and its Implications for an Astrophysical Source of Dark Energy" [CL]

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http://arxiv.org/abs/2304.09817


It was recently claimed that black holes can explain the accelerated expansion of the universe. Here we point out that this claim is based on a confusion about the principle of least action, undermining the link between black holes and dark energy.

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T. Mistele
Thu, 20 Apr 23
12/57

Comments: 5 pages

Model-agnostic cosmological constraints from the baryon acoustic oscillation feature in redshift space [CEA]

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http://arxiv.org/abs/2304.09198


We develop a framework for self-consistently extracting cosmological information from the clustering of tracers in redshift space, $\textit{without}$ relying on model-dependent templates to describe the baryon acoustic oscillation (BAO) feature. Our approach uses the recently proposed Laguerre reconstruction technique for the BAO feature and its linear point $r_{\rm LP}$, and substantially extends it to simultaneously model the multipoles $\ell=0,2,4$ of the anisotropic galaxy 2-point correlation function (2pcf). The approach is `model-agnostic’: it assumes that the non-linear growth of structure smears the BAO feature by an approximately Gaussian kernel with a smearing scale $\sigma_{\rm v}$, but does not assume any fiducial cosmology for describing the shape of the feature itself. Using mock observations for two realistic survey configurations assuming $\Lambda$ cold dark matter ($\Lambda$CDM), combined with Bayesian parameter inference, we show that the linear point $r_{\rm LP}$ and smearing scale $\sigma_{\rm v}$ can be accurately recovered by our method in both existing and upcoming surveys. The precision of the recovery of $r_{\rm LP}$ is always better than $1\%$, while $\sigma_{\rm v}$ can be recovered with $\lesssim10\%$ uncertainty provided the linear galaxy bias $b$ is separately constrained, e.g., using weak lensing observations. Our method is also sensitive to the linear growth rate $f$, albeit with larger uncertainties and systematic errors, especially for upcoming surveys such as DESI. We discuss how our model can be modified to improve the recovery of $f$, such that the resulting constraints on ${f,\sigma_{\rm v},r_{\rm LP}}$ can potentially be used as a test of cosmological models including and beyond $\Lambda$CDM.

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A. Paranjape and R. Sheth
Thu, 20 Apr 23
13/57

Comments: 17 pages, 6 figures, submitted to MNRAS

The two rings of (50000) Quaoar [EPA]

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http://arxiv.org/abs/2304.09237


Quaoar is a classical Trans-Neptunian Object (TNO) with an area equivalent diameter of 1,100 km and an orbital semi-major axis of 43.3 astronomical units. Based on stellar occultations observed between 2018 and 2021, an inhomogeneous ring (Q1R, Quaoar’s first ring) was detected around this body. Aims. A new stellar occultation by Quaoar was observed on August 9th, 2022 aiming to improve Quaoar’s shape models and the physical parameters of Q1R while searching for additional material around the body. Methods. The occultation provided nine effective chords across Quaoar, pinning down its size, shape, and astrometric position. Large facilities, such as Gemini North and the Canada-France-Hawaii Telescope (CFHT), were used to obtain high acquisition rates and signal-to-noise ratios. The light curves were also used to characterize the Q1R ring (radial profiles and orbital elements). Results. Quaoar’s elliptical fit to the occultation chords yields the limb with an apparent semi-major axis of $579.5\pm4.0$ km, apparent oblateness of $0.12\pm0.01$, and area-equivalent radius of $543\pm2$ km. Quaoar’s limb orientation is consistent with Q1R and Weywot orbiting in Quaoar’s equatorial plane. The orbital radius of Q1R is refined to a value of $4,057\pm6$ km. The radial opacity profile of the more opaque ring profile follows a Lorentzian shape that extends over 60 km, with a full width at half maximum (FWHM) of $\sim5$ km and a peak normal optical depth of 0.4. Besides the secondary events related to the already reported rings, new secondary events detected during the August 2022 occultation in three different data sets are consistent with another ring around Quaoar with a radius of $2,520\pm20$ km, assuming the ring is circular and co-planar with Q1R. This new ring has a typical width of 10 km and a normal optical depth of $\sim$0.004. Like Q1R, it also lies outside Quaoar’s classical Roche limit.

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C. Pereira, B. Sicardy, B. Morgado, et. al.
Thu, 20 Apr 23
14/57

Comments: Accepted for publication in Astronomy & Astrophysics (18-April-2023). 18 pages, 12 figures

Steep Balmer decrement in weak AGNs may be not caused by dust extinction: clues from low-luminosity AGNs and changing-look AGNs [GA]

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http://arxiv.org/abs/2304.09435


The hydrogen Balmer decrement (e.g., $\rm H\alpha/H\beta$) is widely adopted as an indicator of the internal reddening of active galactic nuclei (AGNs). This is challenged by some low-luminosity AGNs (LLAGNs) and changing-look AGNs (CLAGNs), which have steep Balmer decrement but without strong evidence for absorption. We compile a sample of normal AGNs and CLAGNs with a wider distribution of bolometric Eddington ratio ($\lambda_{\rm Edd}=L_{\rm bol}/L_{\rm Edd}$) and find a strong negative correlation between $\rm H\alpha/H\beta$ and $\lambda_{\rm Edd}$, which suggests that the Balmer decrement is also accretion-rate dependent. We further explore the Balmer decrement based on the photoionization model using the Cloudy code by considering spectral energy distribution (SED) from the accretion disk with different accretion rates (e.g., disk/corona and truncated disk at high and low Eddington ratios, respectively). Both the standard disk and truncated disk predict a negative correlation of $\rm H\alpha/H\beta-\lambda_{\rm Edd}$, where the relation is steeper in the case of the truncated disk. The negative correlations are also explored in two single CLAGNs. The measured negative correlation of $\rm H\alpha/H\beta$ — $\lambda_{\rm Edd}$ is mainly caused by the lower responsivity $({\rm dlog}L_{\rm line}/{\rm dlog}L_{\rm cont})$ in $\rm H\alpha$ relative to that in $\rm H\beta$, due to the larger optical depth in the former. We propose that the steep Balmer decrements in low-Eddington-ratio AGNs (e.g., some Seyferts 1.5-1.9 and CLAGNs) are not simply caused by absorption but mainly caused by the relatively low flux of ionizing photons.

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J. Wu, Q. Wu, H. Xue, et. al.
Thu, 20 Apr 23
15/57

Comments: 13 pages, 3 figures, Accepted for publication in The Astrophysical Journal

Jellyfish galaxies with the IllustrisTNG simulations — When, where, and for how long does ram pressure stripping of cold gas occur? [GA]

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http://arxiv.org/abs/2304.09196


Jellyfish galaxies are the prototypical examples of satellite galaxies undergoing strong ram pressure stripping (RPS). We analyze the evolution of 535 unique, first-infalling jellyfish galaxies from the TNG50 cosmological hydrodynamical galaxy simulation. These have been visually inspected to be undergoing RPS sometime in the past 5 billion years (since $z=0.5$), have satellite stellar masses $M_{\star}^{\rm sat}\sim10^{8-10.5}{\rm M}\odot$, and live in hosts with $M{\rm 200c}\sim10^{12-14.3}{\rm M}\odot$ at $z=0$. We quantify the cold gas $(\leq10^{4.5}$K) removal using the tracer particles, confirming that for these jellyfish, RPS is the dominant driver of cold gas loss after infall. Half of these jellyfish are completely devoid of cold gas by $z=0$, and these galaxies have earlier infall times and smaller satellite-to-host mass ratios than those that still have some gas today. RPS can act on jellyfish galaxies over long timescales of $\approx1.5-8$Gyr. Jellyfish in more massive hosts are impacted by RPS for a shorter time span and, at a fixed host halo mass, jellyfish with lower stellar masses at $z=0$ have shorter RPS time spans. While RPS may act for long periods of time, the peak RPS period — where at least 50% of the total RPS occurs — begins within $\approx1$Gyr of infall and lasts $\lesssim2$Gyr. During this period, the jellyfish are at host-centric distances between $\sim0.2-2R{\rm 200c}$, illustrating that much of RPS occurs at large distances from the host galaxy. Jellyfish continue forming stars until they have lost $\approx98$% of their cold gas. For groups and clusters in TNG50 $(M_{\rm 200c}\sim10^{13-14.3}{\rm M}\odot)$, jellyfish galaxies deposit more cold gas ($\sim10^{11-12}{\rm M}\odot$) into halos than exist in them at $z=0$, demonstrating that jellyfish, and in general satellite galaxies, are a significant source of cold gas accretion.

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E. Rohr, A. Pillepich, D. Nelson, et. al.
Thu, 20 Apr 23
16/57

Comments: 20 pages, 11 figures + 3 appendices with 4 figures. Submitted to MNRAS. Key figures are 2, 8, 9, 11. See additional jellyfish companion papers today on astro-ph: Zinger+ and Goeller+. All data used in this publication, including the Cosmological Jellyfish Project results, are publicaly available

Neutron Stars on Modified Teleparallel Gravity [CL]

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http://arxiv.org/abs/2301.06432


We investigate compact objects in modified teleparallel gravity with realistic equations of state. We propose a modification on Teleparallel Equivalent of General Relativity, then an appropriate tetrad is applied on the field equations. A specific set of relations showing a equivalency between our gravitational model and the New General Relativity is found. The conservation equation implies that our Tolman-Oppenheimer-Volkoff equations are presented with an effective pressure and energy density, where a free parameter \b{eta}3 is used to construct them. Numerical analysis using realistic equations of state is made, the behavior of mass, radius and the relation mass-radius as functions of \b{eta}3 is also investigated.

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S. Vilhena, S. Duarte, M. Dutra, et. al.
Thu, 20 Apr 23
17/57

Comments: 8 pages, 5 figures

Toward a better understanding of the mid-infrared emission in the LMC [GA]

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http://arxiv.org/abs/2304.09519


In this paper we aim to constrain for the first time the dust emission in the mid-to-far infrared domain, in the LMC, with the use of the Spitzer IRS and MIPS SED data, combined with Herschel data. We also consider UV extinction predictions derived from modeling. We selected 10 regions observed as part of the SAGE-Spec program, to probe dust properties in various environments (diffuse, molecular and ionized regions). All data were smoothed to the 40arcsec angular resolution. The SEDs were modeled with DustEM models, using the standard Mathis RF, as well as three additional RFs, with stellar clusters ages ranging from 4 Myr to 600 Myr. Standard dust models used to reproduce the Galactic diffuse medium are clearly not able to reproduce the dust emission in the MIR wavelength domain. This analysis evidences the need of adjusting parameters describing the dust size distribution and shows a clear distinct behavior according to the type of environments. In addition, whereas the small grain emission always seems to be negligible at long wavelengths in our Galaxy, the contribution of this small dust component could be more important than expected, in the submm-mm range, in the LMC averaged SED. Properties of the small dust component of the LMC are clearly different from those of our Galaxy. Its abundance, significantly enhanced, could be the result of large grains shattering due to strong shocks or turbulence. In addition, this grain component in the LMC systematically shows smaller grain size in the ionized regions compared to the diffuse medium. Predictions of extinction curves show significantly distinct behaviors depending on the dust models but also from one region to another. Comparison of model predictions with the LMC mean extinction curve shows that no model gives satisfactory agreement using the Mathis radiation field while using a harder radiation field tends to improve the agreement

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D. Paradis, C. Mény, K. Demyk, et. al.
Thu, 20 Apr 23
18/57

Comments: Accepted for publication in A&A

The Primordial Black Holes that Disappeared: Connections to Dark Matter and MHz-GHz Gravitational Waves [CL]

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http://arxiv.org/abs/2304.09194


In the post-LIGO era, there has been a lot of focus on primordial black holes (PBHs) heavier than $\sim 10^{15}$g as potential dark matter (DM) candidates. We point out that the branch of the PBH family that disappeared – PBHs lighter than $\sim 10^9$g that ostensibly Hawking evaporated away in the early Universe – also constitute an interesting frontier for DM physics. Hawking evaporation itself serves as a portal through which such PBHs can illuminate new physics, for example by emitting dark sector particles. Taking a simple DM scalar singlet model as a template, we compute the abundance and mass of PBHs that could have provided, by Hawking evaporation, the correct DM relic density. We consider two classes of such PBHs: those originating from curvature perturbations generated by inflation, and those originating from false vacuum collapse during a first-order phase transition. For PBHs of both origins we compute the gravitational wave (GW) signals emanating from their formation stage: from second-order effects in the case of curvature perturbations, and from sound waves in the case of phase transitions. The GW signals have peak frequencies in the MHz-GHz range typical of such light PBHs. We compute the strength of such GWs compatible with the observed DM relic density, and find that the GW signal morphology can in principle allow one to distinguish between the two PBH formation histories.

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T. Gehrman, B. Haghi, K. Sinha, et. al.
Thu, 20 Apr 23
19/57

Comments: 23 pages + references, 8 figures

Detecting and Characterizing Young Quasars. III. The Impact of Gravitational Lensing Magnification [GA]

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http://arxiv.org/abs/2304.09256


We test the impact of gravitational lensing on the lifetime estimates of seven high-redshift quasars at redshift $z\gtrsim6$. The targeted quasars are identified by their small observed proximity zone sizes, which indicate extremely short quasar lifetimes $(t_Q\lesssim10^5 \text{ yrs})$. However, these estimates of quasar lifetimes rely on the assumption that the observed luminosities of the quasars are intrinsic and not magnified by gravitational lensing, which would bias the lifetime estimates towards younger ages. In order to test possible effects of gravitational lensing, we obtain high-resolution images of the seven quasars with the {\em Hubble Space Telescope (HST)} and look for signs of strong lensing. We do not find any evidence of strong lensing, i.e., all quasars are well-described by point sources, and no foreground lensing galaxy is detected. We estimate that the strong lensing probabilities for these quasars are extremely small $(\sim1.4\times10^{-5})$, and show that weak lensing changes the estimated quasar lifetimes by only $\lesssim0.2$ dex. We thus confirm that the short lifetimes of these quasars are intrinsic. The existence of young quasars indicates a high obscured fraction, radiatively inefficient accretion, and/or flickering light curves for high-redshift quasars. We further discuss the impact of lensing magnification on measurements of black hole masses and Eddington ratios of quasars.

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M. Yue, A. Eilers, R. Simcoe, et. al.
Thu, 20 Apr 23
20/57

Comments: 14 pages, 4 figures, 3 tables. Accepted by the Astrophysical Journal

Nustar observation of the binary system 4U 0114+65 [HEAP]

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http://arxiv.org/abs/2304.09295


The high mass X-ray binary system 4U 0114+65 was observed by Nustar in October 2019, and by XMM-Newton in August 2015. Here we performed spectral and timing analysis of the Nustar observation, and carry out timing analysis on the XMM-Newton data. We measured the spin period of the neutron star from both observations and found a spin-up rate $\dot{p} = 1.54 \pm 0.38 \times 10^{-6} s s^{-1}$. During the Nustar observation two flares occured, one occured shortly after the start of the observation and the other near the end separated by a long period of low/quiescent- state. The large and sudden flares mostly resulted from accretion of Corotating Interaction Region (CIR) material. A common spectral model to HMXBs, powerlaw with high energy cutoff and absorption at low energy, gave a good fit to both flaring and quiescent states. A flourescent iron line was not required in fitting any of the states. On the other hand, very tentative evidence of Cyclotron Resonant Scattering Feature (CRSF) at $\sim$ 17 keV was found during fitting using cyclabs model, however fitting improvement was not significant enough to confirm its detection, plus a very narrow width (< 1 keV) was obtained for the line and its first harmonic. Visual inspection of the spectra showed a deficiency of emission near the expected first and second harmonic. Another important feature visually noticed in the spectra is the presence of hard tail above 50 keV. This could be explained by the shocked material bounding the CIR.

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M. Abdallah, R. Samir, D. Leahy, et. al.
Thu, 20 Apr 23
21/57

Comments: N/A

The SunPy Project: An Interoperable Ecosystem for Solar Data Analysis [SSA]

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http://arxiv.org/abs/2304.09794


The SunPy Project is a community of scientists and software developers creating an ecosystem of Python packages for solar physics. The project includes the sunpy core package as well as a set of affiliated packages. The sunpy core package provides general purpose tools to access data from different providers, read image and time series data, and transform between commonly used coordinate systems. Affiliated packages perform more specialized tasks that do not fall within the more general scope of the sunpy core package. In this article, we give a high-level overview of the SunPy Project, how it is broader than the sunpy core package, and how the project curates and fosters the affiliated package system. We demonstrate how components of the SunPy ecosystem, including sunpy and several affiliated packages, work together to enable multi-instrument data analysis workflows. We also describe members of the SunPy Project and how the project interacts with the wider solar physics and scientific Python communities. Finally, we discuss the future direction and priorities of the SunPy Project.

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S. Community, W. Barnes, S. Christe, et. al.
Thu, 20 Apr 23
22/57

Comments: 15 pages, 1 figure, published in Frontiers

The spin and mass ratio affects the gravitational waveforms of binary black hole mergers with a total system mass of 12-130 $\rm{M}_\odot$ [HEAP]

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http://arxiv.org/abs/2304.09396


Analyzing the observations obtained by the LIGO and the Virgo Collaborations, a new era has begun in binary black hole (BBH) merger processes and black hole physics studies. The fact that very massive stars that will become black holes at the end of their evolution are in binary or multiple states adds particular importance to BBH studies. In this study, using the SEOBNRv4$_opt$ gravitational waveform model developed for compact binary systems, many ($\sim 10^6$) models were produced under different initial conditions, and the pre- and post-merge parameters were compared. In the models, it is assumed that the initial total mass (M${\rm{tot}}$) of the binary systems varies between 12-130 $\rm{M}\odot$ with step interval 1$\rm{M}\odot$, the mass ratios ($q = \rm{m}{1i}/\rm{m}{2i}$) vary between 1 and 2 with step interval 0.004, and the initial spin ($\abs{\rchi{1i}} = \abs{\rchi_{2i}}$) value varies between $-0.83$ and $+0.83$ with step interval 0.017. Final spin ($\rchi_{f}$), fractional mass loss (M${FL}$), and the maximum gravitational wave amplitude (h${\rm{max}}$) obtained during the merger were compared with appropriate tables and figures obtained from the results of the relativistic numeric model obtained according to the initial parameters. Our results show that M${\rm{FL}}$ in generated BBH coalescences varied about 2.7 to 9.2\%, and $\rchi{\rm{f}}$ between 0.29 and 0.91. In most of the BBHs we have modeled, we found that M${\rm{FL}}$ varies inversely with $q$. However, it has been found that M${\rm{FL}}$ values are not always inversely varied to the $q$ parameter in systems of opposite initial spin, where the large mass black hole component is positively oriented. Accordingly, it is understood that the values of M$_{\rm{FL}}$ decrease to a certain point of $q$ and then increase according to the increasing direction of $q$.

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&. Özbakır and K. Yakut
Thu, 20 Apr 23
23/57

Comments: 29 pages, 5 figure, 5 tables, submitted for publication

The formation of the first black holes [HEAP]

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http://arxiv.org/abs/2304.09311


The most massive black holes at redshifts z = 6 were already over billion solar masses. In this chapter, we discuss the formation and growth of the first black holes in the Universe. The deaths of massive primordial stars provide potential seeds of supermassive black holes. Theoretical models predict that the seed black hole masses range from 10 to 100,000 solar masses. Their initial fueling may be limited by feedback from its progenitor star, the black hole itself, and nearby star formation. Once the halo and galaxy surpasses a critical mass, black hole growth may accelerate as the central gravitational potential deepens with strong ensuing star formation.

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J. Wise
Thu, 20 Apr 23
24/57

Comments: 30 pages, 7 figures. This chapter is the pre-print of the version currently in production. Please cite this chapter as the following: J. H. Wise, “The formation of the first black holes,” in The Encyclopedia of Cosmology (Set 2): Black Holes, edited by Z. Haiman (World Scientific, New Jersey, 2023)

Numerically studying the degeneracy problem in extreme finite-source microlensing events [IMA]

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http://arxiv.org/abs/2304.09529


Most transit microlensing events due to very low-mass lens objects suffer from extreme finite-source effects. While modeling their light curves, there is a known continuous degeneracy between their relevant lensing parameters, i.e., the source angular radius normalized to the angular Einstein radius $\rho_{\star}$, the Einstein crossing time $t_{\rm E}$, the lens impact parameter $u_{0}$, the blending parameter, and the stellar apparent magnitude. In this work, I numerically study the origin of this degeneracy. I find that these light curves have 5 observational parameters (i.e., the baseline magnitude, the maximum deviation in the magnification factor, the Full Width at Half Maximum $\rm{FWHM}=2 t_{\rm{HM}}$, the deviation from top-hat model, the time of the maximum time-derivative of microlensing light curves $T_{\rm{max}}=t_{\rm E}\sqrt{\rho_{\star}^{2}-u_{0}^{2}}$). For extreme finite-source microlensing events due to uniform source stars we get $t_{\rm{HM}}\simeq T_{\rm{max}}$, and the deviation from the top-hat model tends to zero which both cause the known continuous degeneracy. When either $\rho_{\star}\lesssim10$ or the limb-darkening effect is considerable $t_{\rm{HM}}$, and $T_{\rm{max}}$ are two independent observational parameters. I use a numerical approach, i.e., Random Forests containing $100$-$120$ Decision Trees, to study how these observational parameters are efficient in yielding the lensing parameters. These machine learning models find the mentioned 5 lensing parameters for finite-source microlensing events from uniform, and limb-darkened source stars with the average $R^{2}$-scores of $0.87$, and $0.84$, respectively. $R^{2}$-score for evaluating the lens impact parameter gets worse on adding limb darkening, and for extracting the limb-darkening coefficient itself this score falls as low as $0.67$.

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S. Sajadian
Thu, 20 Apr 23
25/57

Comments: 10 pages, 6 figures

Observations of Stellar-Mass Black Holes in the Galaxy [HEAP]

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http://arxiv.org/abs/2304.09368


Stellar-mass black holes (BHs), with masses comparable to stars, are a major constituent of our Milky Way galaxy. This chapter describes the landscape of challenging, and long-sought efforts to identify these objects in the Galaxy. The first stellar-mass BHs were identified as persistent, but highly variable cosmic X-ray sources. Later, transient BH candidates were detected, and now far outnumber the persistent sources. Decades of effort have also yielded candidate BHs via gravitational microlensing and their orbital effect on binary companions. Populations of BH systems have begun to emerge from these detection strategies, offering insight into the astrophysical context in which BHs exist and driving questions about the formation, assembly, and ongoing evolution of these enigmatic objects.

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M. MacLeod and J. Grindlay
Thu, 20 Apr 23
26/57

Comments: This chapter is the pre-print of the version currently in production. Please cite this chapter as the following: M. MacLeod and J. Grindlay “Observations of Stellar-Mass Black Holes in the Galaxy,” in The Encyclopedia of Cosmology (Set 2): Black Holes, edited by Z. Haiman (World Scientific, New Jersey, 2023). We welcome comments or feedback

Clockwork Cosmology [CL]

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http://arxiv.org/abs/2304.09205


The higher order generalisation of the clockwork mechanism to gravitational interactions provides a means to generate an exponentially suppressed coupling to matter from a fundamental theory of multiple interacting gravitons, without introducing large hierarchies in the underlying potential and without the need for a dilaton, suggesting a possible application to the hierarchy problem. We work in the framework of ghost free multi-gravity with “nearest-neighbour” interactions, and present a formalism by which one is able to construct potentials such that the theory will always exhibit this clockwork effect. We also consider cosmological solutions to the general theory, where all metrics are of FRW form, with site-dependent scale factors/lapses. We demonstrate the existence of multiple deSitter vacua where all metrics share the same Hubble parameter, and we solve the modified Einstein equations numerically for an example clockwork model constructed using our formalism, finding that the evolution of the metric that matter couples to is essentially equivalent to that of general relativity at the modified Planck scale. It is important to stress that while we focus on the application to clockwork theories, our work is entirely general and facilitates finding cosmological solutions to any ghost free multi-gravity theory with “nearest-neighbour” interactions. Moreover, we clarify previous work on the continuum limit of the theory, which is generically a scalar-tensor braneworld, using the Randall-Sundrum model as a special case and showing how the discrete-clockwork cosmological results map to the continuum results in the appropriate limit.

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K. Wood, P. Saffin and A. Avgoustidis
Thu, 20 Apr 23
27/57

Comments: 48 pages, 4 figures

Internal kinematics and structure of the bulge globular cluster NGC 6569 [GA]

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http://arxiv.org/abs/2304.09472


In the context of a project aimed at characterizing the properties of star clusters in the Galactic bulge, here we present the determination of the internal kinematics and structure of the massive globular cluster NGC 6569. The kinematics has been studied by means of an unprecedented spectroscopic dataset acquired in the context of the ESO-VLT Multi-Instrument Kinematic Survey (MIKiS) of Galactic globular clusters, combining the observations from four different spectrographs. We measured the line-of-sight velocity of a sample of almost 1300 stars distributed between ~0.8″ and 770″ from the cluster center. From a sub-sample of high-quality measures, we determined the velocity dispersion profile of the system over its entire radial extension (from ~ 5″ to ~ 200″ from the center), finding the characteristic behavior usually observed in globular clusters, with a constant inner plateau and a declining trend at larger radii. The projected density profile of the cluster has been obtained from resolved star counts, by combining high-resolution photometric data in the center, and the Gaia EDR3 catalog radially extended out to ~20′ for a proper sampling of the Galactic field background. The two profiles are properly reproduced by the same King model, from which we estimated updated values of the central velocity dispersion, main structural parameters (such as the King concentration, the core, half-mass, and tidal radii), total mass, and relaxation times. Our analysis also reveals a hint of ordered rotation in an intermediate region of the cluster (40″<r<90″, corresponding to $ 2 r_c<r<4.5 r_c$), but additional data are required to properly assess this possibility.

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C. Pallanca, S. Leanza, F. Ferraro, et. al.
Thu, 20 Apr 23
28/57

Comments: Accepted for publication in The Astrophysical Journal; 21 pages, 10 figures, 4 tables

RadioAstron Space VLBI Imaging of the jet in M87: I. Detection of high brightness temperature at 22 GHz [GA]

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http://arxiv.org/abs/2304.09816


We present results from the first 22 GHz space very-long-baseline interferometric (VLBI) imaging observations of M87 by RadioAstron. As a part of the Nearby AGN Key Science Program, the source was observed in Feb 2014 at 22 GHz with 21 ground stations, reaching projected $(u,v)$-spacings up to $\sim11\,$G$\lambda$. The imaging experiment was complemented by snapshot RadioAstron data of M87 obtained during 2013–2016 from the AGN Survey Key Science Program. Their longest baselines extend up to $\sim25\,$G$\lambda$. For all these measurements, fringes are detected only up to $\sim$2.8 Earth Diameter or $\sim$3 G$\lambda$ baseline lengths, resulting in a new image with angular resolution of $\sim150\,\mu$as or $\sim20$ Schwarzschild radii spatial resolution. The new image not only shows edge-brightened jet and counterjet structures down to submilliarcsecond scales but also clearly resolves the VLBI core region. While the overall size of the core is comparable to those reported in the literature, the ground-space fringe detection and slightly super-resolved RadioAstron image suggest the presence of substructures in the nucleus, whose minimum brightness temperature exceeds $T_{\rm B, min}\sim10^{12}\,$K. It is challenging to explain the origin of this record-high $T_{\rm B, min}$ value for M87 by pure Doppler boosting effect with a simple conical jet geometry and known jet speed. Therefore, this can be evidence for more extreme Doppler boosting due to a blazar-like small jet viewing angle or highly efficient particle acceleration processes occurring already at the base of the outflow.

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J. Kim, T. Savolainen, P. Voitsik, et. al.
Thu, 20 Apr 23
29/57

Comments: 27 pages, 13 figures, accepted for publication in ApJ

On the energy flow of $λ$ in Hořava-Lifshitz cosmology [CEA]

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http://arxiv.org/abs/2304.09766


Ho\v{r}ava-Lifshitz gravity has been proposed as a ghost-free quantum gravity model candidate with an anisotropic UV-scaling between space and time. We present here a cosmological background analysis of two different formulations of the theory, with particular focus on the running of the parameter $\lambda$. Using a large dataset consisting of Cosmic Microwave Background data from {\it Planck}, Pantheon+ supernovae catalogue, SH0ES Cepheid variable stars, Baryon acoustic oscillations (BAO), Cosmic Chronometers, and gamma-ray bursts (GRB), we arrive at new bounds on the cosmological parameters, in particular $\lambda$, which describes deviation from classical general relativity. For the detailed balance scenario we arrive at the bound $\lambda=1.02726\pm0.00012$, and for beyond detailed balance the limit reads $\lambda=0.9949^{+0.0045}_{-0.0046}$. We also study the influence of different data sets and priors, and we find that removing low-redshift data generally moves $\lambda$ closer towards UV values, whilst simultaneously widening the error bars. In the detailed balance scenario, this effect is more noticeable, and $\lambda$ takes on values that are significantly below unity, which corresponds to the infrared limit of the theory.

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E. Czuchry and N. Nilsson
Thu, 20 Apr 23
30/57

Comments: 16 pages, 2 tables, 1 figure

BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1 [GA]

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http://arxiv.org/abs/2304.09222


We present a constraint on the abundance of supergiant (SG) stars at redshift z approx. 1, based on recent observations of a strongly lensed arc at this redshift. First we derive a free-form model of MACS J0416.1-2403 using data from the BUFFALO program. The new lens model is based on 72 multiply lensed galaxies that produce 214 multiple images, making it the largest sample of spectroscopically confirmed lensed galaxies on this cluster. The larger coverage in BUFFALO allows us to measure the shear up to the outskirts of the cluster, and extend the range of lensing constraints up to ~ 1 Mpc from the central region, providing a mass estimate up to this radius. As an application, we make predictions for the number of high-redshift multiply-lensed galaxies detected in future observations with JWST. Then we focus on a previously known lensed galaxy at z=1.0054, nicknamed Spock, which contains four previously reported transients. We interpret these transients as microcaustic crossings of SG stars and compute the probability of such events. Based on simplifications regarding the stellar evolution, we find that microlensing (by stars in the intracluster medium) of SG stars at z=1.0054 can fully explain these events. The inferred abundance of SG stars is consistent with either (1) a number density of stars with bolometric luminosities beyond the Humphreys-Davidson (HD) limit (L ~ $6\times10^5 L_{\odot}$) that is below 400 stars per sq. kpc, or (2) the absence of stars beyond the HD limit but with a SG number density of ~ 9000 per sq. kpc for stars with luminosities between $10^5$ and $6\times10^5$. This is equivalent to one SG star per 10×10 pc$^2$. We finally make predictions for future observations with JWST’s NIRcam. We find that in observations made with the F200W filter that reach 29 mag AB, if cool red SG stars exist at z~1 beyond the HD limit, they should be easily detected in this arc

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J. Diego, S. Li, A. Meena, et. al.
Thu, 20 Apr 23
31/57

Comments: 24 pages & 18 figures

The ALMA REBELS Survey: Discovery of a massive, highly star-forming and morphologically complex ULIRG at $z =7.31$ [GA]

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http://arxiv.org/abs/2304.09206


We present Atacama Large Millimeter/Submillimeter Array (ALMA) [CII] and $\sim158$ $\rm\mu m$ continuum observations of REBELS-25, a massive, morphologically complex ultra-luminous infrared galaxy (ULIRG; $L_{\rm IR}=1.5^{+0.8}{-0.5}\times10^{12}$ L$\odot$) at $z=7.31$, spectroscopically confirmed by the Reionization Era Bright Emission Line Survey (REBELS) ALMA Large Programme. REBELS-25 has a significant stellar mass of $M_{*}=8^{+4}_{-2}\times10^{9}$ M$_\odot$. From dust-continuum and ultraviolet observations, we determine a total obscured + unobscured star formation rate of SFR $=199^{+101}_{-63}$ M$_\odot$ yr$^{-1}$. This is about four times the SFR estimated from an extrapolated main-sequence. We also infer a [CII]-based molecular gas mass of $M_{\rm H_2}=5.1^{+5.1}_{-2.6}\times10^{10}$ $M_\odot$, implying a molecular gas depletion time of $ t_{\rm depl, H_2}=0.3^{+0.3}_{-0.2}$ Gyr. We observe a [CII] velocity gradient consistent with disc rotation, but given the current resolution we cannot rule out a more complex velocity structure such as a merger. The spectrum exhibits excess [CII] emission at large positive velocities ($\sim500$ km s$^{-1}$), which we interpret as either a merging companion or an outflow. In the outflow scenario, we derive a lower limit of the mass outflow rate of 200 M$_\odot$ yr$^{-1}$, which is consistent with expectations for a star formation-driven outflow. Given its large stellar mass, SFR and molecular gas reservoir $\sim700$ Myr after the Big Bang, we explore the future evolution of REBELS-25. Considering a simple, conservative model assuming an exponentially declining star formation history, constant star formation efficiency, and no additional gas inflow, we find that REBELS-25 has the potential to evolve into a galaxy consistent with the properties of high-mass quiescent galaxies recently observed at $z\sim4$.

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A. Hygate, J. Hodge, E. Cunha, et. al.
Thu, 20 Apr 23
32/57

Comments: Accepted for publication in MNRAS. 21 pages, 8 figures

Physical and Surface Properties of Comet Nuclei from Remote Observations [EPA]

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http://arxiv.org/abs/2304.09309


We summarize the collective knowledge of physical and surface properties of comet nuclei, focusing on those that are obtained from remote observations. We now have measurements or constraints on effective radius for over 200 comets, rotation periods for over 60, axial ratios and color indices for over 50, geometric albedos for over 25, and nucleus phase coefficients for over 20. The sample has approximately tripled since the publication of Comets II, with IR surveys using Spitzer and NEOWISE responsible for the bulk of the increase in effective radii measurements. Advances in coma morphology studies and long-term studies of a few prominent comets have resulted in meaningful constraints on rotation period changes in nearly a dozen comets, allowing this to be added to the range of nucleus properties studied. The first delay-Doppler radar and visible light polarimetric measurements of comet nuclei have been made since Comets II and are considered alongside the traditional methods of studying nuclei remotely. We use the results from recent in situ missions, notably Rosetta, to put the collective properties obtained by remote observations into context, emphasizing the insights gained into surface properties and the prevalence of highly elongated and/or bilobate shapes. We also explore how nucleus properties evolve, focusing on fragmentation and the likely related phenomena of outbursts and disintegration. Knowledge of these behaviors has been shaped in recent years by diverse sources: high resolution images of nucleus fragmentation and disruption events, the detection of thousands of small comets near the Sun, regular photometric monitoring of large numbers of comets throughout the solar system, and detailed imaging of the surfaces of mission targets. Finally, we explore what advances in the knowledge of the bulk nucleus properties may be enabled in coming years.

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M. Knight, R. Kokotanekova and N. Samarasinha
Thu, 20 Apr 23
33/57

Comments: 43 pages, 6 figures. Chapter in press for the book Comets III, edited by K. Meech and M. Combi, University of Arizona Press

Jellyfish galaxies with the IllustrisTNG simulations — No enhanced population-wide star formation according to TNG50 [GA]

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http://arxiv.org/abs/2304.09199


Due to ram-pressure stripping, jellyfish galaxies are thought to lose large amounts, if not all, of their interstellar medium. Nevertheless, some, but not all, observations suggest that jellyfish galaxies exhibit enhanced star formation compared to control samples, even in their ram pressure-stripped tails. We use the TNG50 cosmological gravity+magnetohydrodynamical simulation, with an average spatial resolution of 50-200 pc in the star-forming regions of galaxies, to quantify the star formation activity and rates (SFRs) of more than 700 jellyfish galaxies at $z=0-1$ with stellar masses $10^{8.3-11}\,\mathrm{M}\odot$ in hosts with mass $10^{11.5-14.3}\,\mathrm{M}\odot$. We extract their global SFRs, the SFRs within their main stellar body vs. within the tails, and we follow the evolution of the star formation along their individual evolutionary tracks. We compare the findings for jellyfish galaxies to those of diversely-constructed control samples, including against satellite and field galaxies with matched redshift, stellar mass, gas fraction and host halo mass. According to TNG50, star formation and ram-pressure stripping can indeed occur simultaneously within any given galaxy, and frequently do so. Moreover, star formation can also take place within the ram pressure-stripped tails, even though the latter is typically subdominant. However, TNG50 does not predict elevated population-wide SFRs in jellyfish compared to analog satellite galaxies with the same stellar mass or gas fraction. Simulated jellyfish galaxies do undergo bursts of elevated star formation along their history but, at least according to TNG50, these do not translate into a population-wide enhancement at any given epoch.

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J. Göller, G. Joshi, E. Rohr, et. al.
Thu, 20 Apr 23
34/57

Comments: 20 pages, 10 figures, 1 table, submitted to MNRAS. See additional jellyfish companion papers today on astro-ph: Zinger et al. and Rohr et al

3D simulations of AGB stellar winds — II. Ray-tracer implementation and impact of radiation on the outflow morphology [SSA]

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http://arxiv.org/abs/2304.09786


Stars with an initial mass below ~ 8 Msun evolve through the asymptotic giant branch (AGB) phase, during which they develop strong stellar winds. Recent observations have revealed significant morphological complexities in their outflows, most likely caused by a companion. We study the impact of the radiation force on such companion-perturbed AGB outflows. We present the implementation of a ray tracer for radiative transfer in smoothed particle hydrodynamics (SPH) and compared four different descriptions of radiative transfer: the free-wind, the geometrical, the Lucy, and the attenuation approximation. For both low and high mass-loss rates, the velocity profile of the outflow is modified when going from the free-wind to the geometrical approximation, also resulting in a different morphology. In the case of a low mass-loss rate, the effect of the Lucy and attenuation approximation is negligible due to the low densities but morphological differences appear in the high mass-loss rate regime. By comparing the radiative equilibrium temperature and radiation force to full 3D radiative transfer, we show that the Lucy approximation works best. Although, close to the companion, artificial heating occurs and it fails to simulate the shadow cast by the companion. The attenuation approximation produces a lower equilibrium temperature and weaker radiation force, but it produces the shadow cast by the companion. From the predictions of the 3D radiative transfer, we also conclude that a radially directed radiation force is a reasonable assumption. The radiation force thus plays a critical role in dust-driven AGB winds, impacting the velocity profile and morphological structures. For low mass-loss rates, the geometrical approximation suffices, while high mass-loss rates require a more rigorous method, where the Lucy approximation provides the most accurate results although not accounting for all effects.

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M. Esseldeurs, L. Siess, F. Ceuster, et. al.
Thu, 20 Apr 23
35/57

Comments: N/A

Fabrication of a 64-Pixel TES Microcalorimeter Array with Iron Absorbers Uniquely Designed for 14.4-keV Solar Axion Search [IMA]

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http://arxiv.org/abs/2304.09539


If a hypothetical elementary particle called an axion exists, to solve the strong CP problem, a 57Fe nucleus in the solar core could emit a 14.4-keV monochromatic axion through the M1 transition. If such axions are once more transformed into photons by a 57Fe absorber, a transition edge sensor (TES) X-ray microcalorimeter should be able to detect them efficiently. We have designed and fabricated a dedicated 64-pixel TES array with iron absorbers for the solar axion search. In order to decrease the effect of iron magnetization on spectroscopic performance, the iron absorber is placed next to the TES while maintaining a certain distance. A gold thermal transfer strap connects them. We have accomplished the electroplating of gold straps with high thermal conductivity. The residual resistivity ratio (RRR) was over 23, more than eight times higher than a previous evaporated strap. In addition, we successfully electroplated pure-iron films of more than a few micrometers in thickness for absorbers and a fabricated 64-pixel TES calorimeter structure.

Read this paper on arXiv…

Y. Yagi, T. Hayashi, K. Tanaka, et. al.
Thu, 20 Apr 23
36/57

Comments: 5 pages, 5 figures, published in IEEE Transactions on Applied Superconductivity on 8 March 2023

Two Warm Super-Earths Transiting the Nearby M Dwarf TOI-2095 [EPA]

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http://arxiv.org/abs/2304.09189


We report the detection and validation of two planets orbiting TOI-2095 (TIC 235678745). The host star is a 3700K M1V dwarf with a high proper motion. The star lies at a distance of 42 pc in a sparsely populated portion of the sky and is bright in the infrared (K=9). With data from 24 Sectors of observation during TESS’s Cycles 2 and 4, TOI-2095 exhibits two sets of transits associated with super-Earth-sized planets. The planets have orbital periods of 17.7 days and 28.2 days and radii of 1.30 and 1.39 Earth radii, respectively. Archival data, preliminary follow-up observations, and vetting analyses support the planetary interpretation of the detected transit signals. The pair of planets have estimated equilibrium temperatures of approximately 400 K, with stellar insolations of 3.23 and 1.73 times that of Earth, placing them in the Venus zone. The planets also lie in a radius regime signaling the transition between rock-dominated and volatile-rich compositions. They are thus prime targets for follow-up mass measurements to better understand the properties of warm, transition radius planets. The relatively long orbital periods of these two planets provide crucial data that can help shed light on the processes that shape the composition of small planets orbiting M dwarfs.

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E. Quintana, E. Gilbert, T. Barclay, et. al.
Thu, 20 Apr 23
37/57

Comments: Submitted to AAS Journals

Confronting strange stars with compact-star observations and new physics [HEAP]

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http://arxiv.org/abs/2304.09614


Strange stars ought to exist in the universe according to the strange quark matter hypothesis, which states that matter made of roughly equal numbers of up, down, and strange quarks could be the true ground state of baryonic matter rather than ordinary atomic nuclei. Theoretical models of strange quark matter, such as the standard MIT bag model, the density-dependent quark mass model, or the quasi-particle model, however, appear to be unable to reproduce some of the properties (masses, radii and tidal deformabilities) of recently observed compact stars. This is different if alternative gravity theory (e.g., non-Newtonian gravity) or dark matter (e.g., mirror dark matter) are considered, which resolve these issues. The possible existence of strange stars could thus provide a clue to new physics, as discussed in this review.

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S. Yang, C. Pi, X. Zheng, et. al.
Thu, 20 Apr 23
38/57

Comments: 26 pages, 11 figures. Review paper accepted for publication in Universe

Investigation of Stellar Kinematics and Ionized gas Outflows in Local [U]LIRGs [GA]

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http://arxiv.org/abs/2304.09425


We explore properties of stellar kinematics and ionized gas in a sample of 1106 local [U]LIRGs from the AKARI telescope. We combine data from $Wide-field\ Infrared\ Survey\ Explorer$ (WISE) and Sloan Digital Sky Survey (SDSS) Data Release 13 (DR13) to fit the spectral energy distribution (SED) of each source to constrain the contribution of AGN to the total IR luminosity and estimate physical parameters such as stellar mass and star-formation rate (SFR). We split our sample into AGNs and weak/non-AGNs. We find that our sample is considerably above the main sequence. The highest SFRs and stellar masses are associated with ULIRGs. We also fit the H$\beta$ and H$\alpha$ regions to characterize the outflows. We find that the incidence of ionized gas outflows in AGN [U]LIRGs ($\sim$ 72\%) is much higher than that in weak/non-AGN ones ($\sim$ 39\%). The AGN ULIRGs have extreme outflow velocities (up to $\sim$ 2300 km s$^{-1}$) and high mass outflow rates (up to $\sim$ 60 \solarm~yr$^{-1}$). Our results suggest that starbursts are insufficient to produce such powerful outflows. We explore the correlations of SFR and specific SFR (sSFR) with ionized gas outflows. We find that AGN hosts with the highest SFRs exhibit a negative correlation between outflow velocity and sSFR. Therefore, in AGNs containing large amounts of gas, the negative feedback scenario might be suggested.

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A. Ayubinia, Y. Xue, H. Le, et. al.
Thu, 20 Apr 23
39/57

Comments: 20 pages, 14 figures, accepted for publication in ApJ

Does Feedback from Supermassive Blackhole Co-evolve With Host In Type 2 Quasars? [GA]

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http://arxiv.org/abs/2304.09450


The feedback from accretion of central supermassive black holes (SMBHs) is a hot topic in the co-evolution of the SMBHs and their host galaxies. By tracing the large scale outflow by the line profile and bulk velocity shift of $[ \rm O~{\scriptsize III}]~ \lambda 5007$, the evolutionary role of outflow is studied here on a large sample of 221 type 2 quasars (QSO2s) extracted from Reyes et al.
By following our previous study on local Seyfert 2 galaxies, the current spectral analysis on the SDSS spectroscopic database enables us to arrive at following results: (1) by using the Lick indices, we confirm that QSO2s are on average associated with younger stellar populations than Seyfert galaxies; (2) QSO2s with a stronger outflow are tend to be associated with a younger stellar population, which implies a coevolution between the feedback from SMBH and the host in QSO2s; (3) although an occupation at the high $L_{\rm bol}/L_{\rm Edd}$ end, the QSO2s follow the $L_{\rm bol}/L_{\rm Edd}$-$D_{n}(4000)$ sequence established from local, less-luminous Seyfert galaxies, which suggests a decrease of accretion activity of SMBH and feedback as the circumnuclear stellar population continuously ages.

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S. Jin, J. Wang, M. Kong, et. al.
Thu, 20 Apr 23
40/57

Comments: 15 pages, 8 figures, and 3 tables, accepted for publication in ApJ

Efficient simulations of ionized ISM emission lines: A detailed comparison between the FIRE high-redshift suite and observations [GA]

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http://arxiv.org/abs/2304.09261


The Atacama Large Millimeter/Submillimeter Array (ALMA) in the sub-millimeter and the James Webb Space Telescope (JWST) in the infrared have achieved robust spectroscopic detections of emission lines from the interstellar medium (ISM) in some of the first galaxies. These unprecedented measurements provide valuable information regarding the ISM properties, stellar populations, galaxy morphologies, and kinematics in these high-redshift galaxies and, in principle, offer powerful tests of state-of-the-art galaxy formation models, as implemented in hydrodynamical simulations. To facilitate direct comparisons between simulations and observations, we develop a fast post-processing pipeline for predicting the line emission from the HII regions around simulated star particles, accounting for spatial variations in the surrounding gas density, metallicity, temperature, and incident radiation spectrum. Our ISM line emission model currently captures H$\alpha$, H$\beta$, and all of the [OIII] and [OII] lines targeted by ALMA and the JWST at $z>6$. We illustrate the power of this approach by applying our line emission model to the publicly available FIRE high-$z$ simulation suite and perform a detailed comparison with current observations. We show that the FIRE mass–metallicity relation is in $1\sigma$ agreement with ALMA/JWST measurements after accounting for the inhomogeneities in ISM properties. We also quantitatively validate the one-zone model description, which is widely used for interpreting [OIII] and H$\beta$ line luminosity measurements. This model is publicly available and can be implemented on top of a broad range of galaxy formation simulations for comparison with JWST and ALMA measurements.

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S. Yang, A. Lidz, A. Smith, et. al.
Thu, 20 Apr 23
41/57

Comments: 15 pages, 13 figures

Detection of a Super-Virial Hot Component in the Milky Way Circumgalactic Medium Along Multiple Sight-Lines by Using the Stacking Technique [GA]

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http://arxiv.org/abs/2304.09641


The study of the elusive hot component ($T \gtrsim 10^7$ K) of the Milky Way circumgalactic medium (CGM) is a novel topic to understand Galactic formation and evolution. In this work, we use the stacking technique through 46 lines of sight with Chandra ACIS-S HETG totaling over 10Ms of exposure time and 9 lines of sight with ACIS-S LETG observations totaling over 1Ms of exposure time, to study in absorption the presence of highly ionized metals arising from the super-virial temperature phase of the CGM. Focusing in the spectral range $4 – 8$ $\r{A}$, we were able to confirm the presence of this hot phase with high significance. We detected transitions of Si XIV K$\alpha$ (with total significance of 6.0$\sigma$) and, for the first time, SXVI K (total significance 4.8$\sigma$) in the rest frame of our own Galaxy. For S XVI K$\alpha$ we found a column density of $1.50^{+0.44}_{-0.38} \times 10^{16} \mathrm{cm}^{-2}$. For Si XIV K$\alpha$ we measured a column density of $0.87\pm{0.16} \times 10^{16} \mathrm{cm}^{-2}$. The lines of sight used in this work are spread across the sky, probing widely separated regions of the CGM. Therefore, our results indicate that this newly discovered hot medium extends throughout the halo, and is not related only to the Galactic Bubbles. The hot gas location, distribution, and covering factor, however, remain unknown. This component might contribute significantly to the missing baryons and metals in the Milky Way.

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A. Lara-DI, S. Mathur, Y. Krongold, et. al.
Thu, 20 Apr 23
42/57

Comments: N/A

Investigating the large-scale environment of wide-angle tailed radio galaxies in the local Universe [CEA]

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http://arxiv.org/abs/2304.09192


We present a statistical analysis of the large-scale (up to 2 Mpc) environment of an homogeneous and complete sample, both in radio and optical selection, of wide-angle tailed radio galaxies (WATs) in the local Universe (i.e., with redshifts $z\lesssim$ 0.15). The analysis is carried out using the parameters obtained from cosmological neighbors within 2 Mpc of the target source. Results on WATs large-scale environments are then compared with that of Fanaroff-Riley type I (FR Is) and type II (FR IIs) radio galaxies, listed in two others homogeneous and complete catalogs, and selected with the same criterion adopted for the WATs catalog. We obtain indication that at low redshift WATs inhabit environments with a larger number of galaxies than that of FR Is and FR IIs. In the explored redshift range, the physical size of the galaxy group/cluster in which WATs reside appears to be almost constant with respect to FR Is and FR IIs, being around 1 Mpc. From the distribution of the concentration parameter, defined as the ratio between the number of cosmological neighbors lying within 500 kpc and within 1 Mpc, we conclude that WATs tend to inhabit the central region of the group/cluster in which they reside, in agreement with the general paradigm that WATs are the cluster BCG.

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V. Missaglia, A. Paggi, F. Massaro, et. al.
Thu, 20 Apr 23
43/57

Comments: 8 pages, 5 figures, 1 table. Accepted for publication on A&A

Dark matter effects in modified teleparallel gravity [CL]

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http://arxiv.org/abs/2304.07364


This work investigates dark matter (DM) effects in compact objects in modified teleparallel gravity (MTG) in which a modification of Teleparallel Equivalent to General Relativity is used. We applied a tetrad to the modified field equations where a set of relations is found. The conservation equation allows us to rewrite our Tolman-Oppenheimer-Volkoff equations with an effective gravitational coupling constant. As input to these new equations, we use a relativistic mean-field (RMF) model with dark matter content included, obtained from a Lagrangian density with both, hadronic and dark particle degrees of freedom, as well as the Higgs boson, used as a mediator in both sectors of the theory. Through numerical calculations, we analyze the mass-radius diagrams obtained from different parametrizations of the RMF-DM model, generated by assuming different values of the dark particle Fermi momentum and running the free parameter coming from the MTG. Our results show that it is possible for the system simultaneously support more DM content, and be compatible with recent astrophysical data provided by LIGO and Virgo Collaboration, as well as by NASA’s Neutron star Interior Composition Explorer (NICER).

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S. Vilhena, M. Dutra, O. Lourenço, et. al.
Thu, 20 Apr 23
44/57

Comments: 8 pages, 2 figures

Jellyfish galaxies with the IllustrisTNG simulations — Citizen-science results towards large distances, low-mass hosts, and high redshifts [GA]

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http://arxiv.org/abs/2304.09202


We present the “Cosmological Jellyfish” project – a citizen-science classification program to identify jellyfish galaxies within the IllustrisTNG cosmological simulations. Jellyfish (JF) are satellite galaxies that exhibit long trailing gas features — `tails’ — extending from their stellar body. Their distinctive morphology arises due to ram-pressure stripping (RPS) as they move through the background gaseous medium. Using the TNG50 and TNG100 simulations, we construct a sample of $\sim 80,000$ satellite galaxies spanning an unprecedented range of stellar masses, $10^{8.3-12.3}\,\mathrm{M_\odot}$, and host masses of $M_\mathrm{200,c}=10^{10.4-14.6}\,\mathrm{M_\odot}$ back to $z=2$ \citep[extending the work of][]{yun_jellyfish_2019}. Based on this sample, $\sim 90,000$ galaxy images were presented to volunteers in a citizen-science project on the Zooniverse platform who were asked to determine if each galaxy image resembles a jellyfish. Based on volunteer votes, each galaxy was assigned a score determining if it is a JF or not. This paper describes the project, the inspected satellite sample, the methodology, and the classification process that resulted in a dataset of $5,307$ visually-identified jellyfish galaxies. We find that JF galaxies are common in nearly all group- and cluster-sized systems, with the JF fraction increasing with host mass and decreasing with satellite stellar mass. We highlight JF galaxies in three relatively unexplored regimes: low-mass hosts of $M_\mathrm{200,c}\sim10^{11.5-13}\,\mathrm{M_\odot}$, radial positions within hosts exceeding the virial radius $R_\mathrm{200,c}$, and at high redshift up to $z=2$. The full dataset of our jellyfish scores is publicly available and can be used to select and study JF galaxies in the IllustrisTNG simulations.

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E. Zinger, G. Joshi, A. Pillepich, et. al.
Thu, 20 Apr 23
45/57

Comments: submitted to MNRAS ; See additional jellyfish companion papers today on astro-ph: Rohr et al. and Goeller et al.; Jellyfish image gallery: this https URL

POLAR — I: linking the 21-cm signal from the epoch of reionization to galaxy formation [CEA]

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http://arxiv.org/abs/2304.09508


To self-consistently model galactic properties, reionization of the intergalactic medium, and the associated 21-cm signal, we have developed the algorithm polar by integrating the one-dimensional radiative transfer code grizzly with the semi-analytical galaxy formation code L-Galaxies 2020. Our proof-of-concept results are consistent with observations of the star formation rate history, UV luminosity function and the CMB Thomson scattering optical depth. We then investigate how different galaxy formation models affect UV luminosity functions and 21-cm power spectra, and find that while the former are most sensitive to the parameters describing the merger of halos, the latter have a stronger dependence on the supernovae feedback parameters, and both are affected by the escape fraction model.

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Q. Ma, R. Ghara, B. Ciardi, et. al.
Thu, 20 Apr 23
46/57

Comments: MNRAS accepted

Slow Solar Wind Connection Science during Solar Orbiter's First Close Perihelion Passage [SSA]

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http://arxiv.org/abs/2304.09570


The Slow Solar Wind Connection Solar Orbiter Observing Plan (Slow Wind SOOP) was developed to utilise the extensive suite of remote sensing and in situ instruments on board the ESA/NASA Solar Orbiter mission to answer significant outstanding questions regarding the origin and formation of the slow solar wind. The Slow Wind SOOP was designed to link remote sensing and in situ measurements of slow wind originating at open-closed field boundaries. The SOOP ran just prior to Solar Orbiter’s first close perihelion passage during two remote sensing windows (RSW1 and RSW2) between 2022 March 3-6 and 2022 March 17-22, while Solar Orbiter was at a heliocentric distance of 0.55-0.51 and 0.38-0.34 au from the Sun, respectively. Coordinated observation campaigns were also conducted by Hinode and IRIS. The magnetic connectivity tool was used, along with low latency in situ data, and full-disk remote sensing observations, to guide the target pointing of Solar Orbiter. Solar Orbiter targeted an active region complex during RSW1, the boundary of a coronal hole, and the periphery of a decayed active region during RSW2. Post-observation analysis using the magnetic connectivity tool along with in situ measurements from MAG and SWA/PAS, show that slow solar wind, with velocities between 210 and 600 km/s, arrived at the spacecraft originating from two out of the three of the target regions. The Slow Wind SOOP, despite presenting many challenges, was very successful, providing a blueprint for planning future observation campaigns that rely on the magnetic connectivity of Solar Orbiter.

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S. Yardley, C. Owen, D. Long, et. al.
Thu, 20 Apr 23
47/57

Comments: 24 pages, 10 figures

BCS in the Sky: Signatures of Inflationary Fermion Condensation [CL]

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http://arxiv.org/abs/2304.09428


We consider a Bardeen-Cooper-Schrieffer (BCS)-like model in the inflationary background. We show that with an axial chemical potential, the attractive quartic fermion self-interaction can lead to a BCS-like condensation. In the de Sitter (dS) limit of inflation, we perform the first computation of the non-perturbative effective potential that includes the full spacetime curvature effects in the presence of the chemical potential. The corresponding BCS phase transition is always first-order, when the varying Hubble is interpreted as an effective Gibbons-Hawking temperature of dS spacetime. In the condensate phase, the theory can be understood from UV and IR sides as fermionic and bosonic, respectively. This leads to distinctive signatures in the primordial non-Gaussianity of curvature perturbations. Namely, the oscillatory cosmological collider signal is smoothly turned off at a finite momentum ratio, since different momentum ratios effectively probe different energy scales. In addition, such BCS phase transitions can also source stochastic gravitational waves, feasible for future experiments.

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X. Tong, Y. Wang, C. Zhang, et. al.
Thu, 20 Apr 23
48/57

Comments: 30 pages, 8 figures

A blue depression in the optical spectra of M dwarfs [SSA]

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http://arxiv.org/abs/2304.09219


A blue depression is found in the spectra of M dwarfs from 4000 to 4500A. This depression shows an increase toward lower temperatures though is particularly sensitive to gravity and metallicity. It is the single most sensitive feature in the optical spectra of M dwarfs. The depression appears as centered on the neutral calcium resonance line at 4227A and leads to nearby features being weaker by about two orders of magnitude than predicted. We consider a variety of possible causes for the depression including temperature, gravity, metallicity, dust, damping constants, and atmospheric stratification. We also consider relevant molecular opacities which might be the cause identifying AlH, SiH, and NaH in the spectral region. However, none of these solutions are satisfactory. In the absence of a more accurate determination of the broadening of the calcium line perturbed by molecular hydrogen, we find a promising empirical fit using a modified Lorentzian line profile for the calcium resonance line. Such fits provide a simplistic line-broadening description for this calcium resonance line and potentially other un-modelled resonance lines in cool high-pressure atmospheres. Thus we claim the most plausible cause of the blue depression in the optical spectra of M dwarfs is a lack of appropriate treatment of line broadening for atomic calcium. The broad wings of the calcium resonance line develop at temperatures below about 4000K and are analogous to the neutral sodium and potassium features which dominate the red optical spectra of L dwarfs.

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H. Jones, Y. Pavlenko, Y. Lyubchik, et. al.
Thu, 20 Apr 23
49/57

Comments: Accepted in MNRAS

The [OIII] profiles of far-infrared active and non-active optically-selected green valley galaxies [GA]

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http://arxiv.org/abs/2304.09284


We present a study of the $\rm{[OIII]\lambda\,5007}$ line profile in a sub-sample of 8 active galactic nuclei (AGN) and 6 non-AGN in the optically-selected green valley at $\rm{z\,<\,0.5}$ using long-slit spectroscopic observations with the 11 m Southern African Large Telescope. Gaussian decomposition of the line profile was performed to study its different components. We observe that the AGN profile is more complex than the non-AGN one. In particular, in most AGN (5/8) we detect a blue wing of the line. We derive the FWHM velocities of the wing and systemic component, and find that AGN show higher FWHM velocity than non-AGN in their core component. We also find that the AGN show blue wings with a median velocity width of approximately 600 $\rm{km\,s^{-1}}$, and a velocity offset from the core component in the range -90 to -350 $\rm{km\,s^{-1}}$, in contrast to the non-AGN galaxies, where we do not detect blue wings in any of their $\rm{[OIII]\lambda\,5007}$ line profiles. Using spatial information in our spectra, we show that at least three of the outflow candidate galaxies have centrally driven gas outflows extending across the whole galaxy. Moreover, these are also the galaxies which are located on the main sequence of star formation, raising the possibility that the AGN in our sample are influencing SF of their host galaxies (such as positive feedback). This is in agreement with our previous work where we studied SF, morphology, and stellar population properties of a sample of green valley AGN and non-AGN galaxies.

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A. Mahoro, P. Väisänen, M. Pović, et. al.
Thu, 20 Apr 23
50/57

Comments: 15 pages, 6 figures, accepted for publication in ApJ

Black holes as the end state of stellar evolution: Theory and simulations [HEAP]

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http://arxiv.org/abs/2304.09350


The collapse of massive stars is one of the most-studied paths to black hole formation. In this chapter, we review black hole formation during the collapse of massive stars in the broader context of single and binary stellar evolution and the theory of supernova explosions. We provide a concise overview of the evolutionary channels that may lead to black hole formation — the classical route of iron core collapse, collapse due to pair instability in very massive stars, and the hypothetical scenario of supermassive star collapse. We then review the current understanding of the parameter space for black hole formation and black hole birth properties that has emerged from theoretical and computational modelling of supernova explosions and transient observations. Finally, we discuss what the intricate interplay between stellar evolution, stellar explosions, and binary interactions implies for the formation of stellar-mass black holes.

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A. Heger, B. Müller and I. Mandel
Thu, 20 Apr 23
51/57

Comments: 53 pages, 9 figures. This chapter is the pre-print of the version currently in production. Please cite this chapter as the following: A.Heger, B. M\”uller, and I. Mandel. “Black holes as the end state of stellar evolution: Theory and simulations,” in The Encyclopedia of Cosmology (Set 2): Black Holes, edited by Z. Haiman (World Scientific, New Jersey, 2023)

COMAP Early Science: VIII. A Joint Stacking Analysis with eBOSS Quasars [GA]

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http://arxiv.org/abs/2304.09832


We present a new upper limit on the cosmic molecular gas density at $z=2.4-3.4$ obtained using the first year of observations from the CO Mapping Array Project (COMAP). COMAP data cubes are stacked on the 3D positions of 282 quasars selected from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) catalog, yielding a 95% upper limit for flux from CO(1-0) line emission of 0.210 Jy km/s. Depending on the assumptions made, this value can be interpreted as either an average CO line luminosity $L’\mathrm{CO}$ of eBOSS quasars of $\leq 7.30\times10^{10}$ K km pc$^2$ s$^{-1}$, or an average molecular gas density $\rho\mathrm{H_2}$ in regions of the universe containing a quasar of $\leq 2.02\times10^8$ M$\odot$ cMpc$^{-3}$. The $L’\mathrm{CO}$ upper limit falls among CO line luminosities obtained from individually-targeted quasars in the COMAP redshift range, and the $\rho_\mathrm{H_2}$ value is comparable to upper limits obtained from other Line Intensity Mapping (LIM) surveys and their joint analyses. Further, we forecast the values obtainable with the COMAP/eBOSS stack after the full 5-year COMAP Pathfinder survey. We predict that a detection is probable with this method, depending on the CO properties of the quasar sample. Based on these achieved sensitivities, we believe that this technique of stacking LIM data on the positions of traditional galaxy or quasar catalogs is extremely promising, both as a technique for investigating large galaxy catalogs efficiently at high redshift and as a technique for bolstering the sensitivity of LIM experiments, even with a fraction of their total expected survey data.

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D. Dunne, K. Cleary, P. Breysse, et. al.
Thu, 20 Apr 23
52/57

Comments: 15 pages, 8 figures. To be submitted to ApJ

Sample Variance in Cosmological Observations with a Narrow Field-of-View [CEA]

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http://arxiv.org/abs/2304.09191


Surveys with a narrow field-of-view can play an important role in probing cosmology, but inferences from these surveys suffer from large sample variance. The standard method for computing the sample variance is based on two key approximations, and we demonstrate that it can lead to a significant underestimate of the sample variance in narrow surveys. We present a new method for accurately computing the sample variance and apply our method to the recent observations of the warm-hot intergalactic medium (WHIM) based on spectroscopic measurements of blazars. We find that the sample variances in these surveys are significantly larger than the quoted measurement errors; for example, the cosmic mean baryon density contained in the WHIM could be lower by $54\%$ at $1\text{-}\sigma$ fluctuation than estimated in one observation. Accurately quantifying the sample variance is essential in deriving correct interpretations of the measurements in surveys with a small field-of-view.

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P. Espenshade and J. Yoo
Thu, 20 Apr 23
53/57

Comments: 6 pages, 2 figures, submitted to ApJL

FAST-ASKAP Synergy: Quantifying Coexistent Tidal and Ram-Pressure Strippings in the NGC 4636 Group [GA]

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http://arxiv.org/abs/2304.09795


Combining new HI data from a synergetic survey of ASKAP WALLABY and FAST with the ALFALFA data, we study the effect of ram-pressure and tidal interactions in the NGC 4636 group. We develop two parameters to quantify and disentangle these two effects on gas stripping in HI-bearing galaxies: the strength of external forces at the optical-disk edge, and the outside-in extents of HI-disk stripping. We find that gas stripping is widespread in this group, affecting 80% of HI-detected non-merging galaxies, and that 34% are experiencing both types of stripping. Among the galaxies experiencing both effects, the strengths (and extents) of ram-pressure and tidal stripping are independent of each other. Both strengths are correlated with HI-disk shrinkage. The tidal strength is related to a rather uniform reddening of low-mass galaxies ($M_*<10^9\,\text{M}_\odot$) when tidal stripping is the dominating effect. In contrast, ram pressure is not clearly linked to the color-changing patterns of galaxies in the group. Combining these two stripping extents, we estimate the total stripping extent, and put forward an empirical model that can describe the decrease of HI richness as galaxies fall toward the group center. The stripping timescale we derived decreases with distance to the center, from $\mathord{\sim}1\,\text{Gyr}$ around $R_{200}$ to $\mathord{\lesssim}10\,\text{Myr}$ near the center. Gas-depletion happens $\mathord{\sim}3\,\text{Gyr}$ since crossing $2R_{200}$ for HI-rich galaxies, but much quicker for HI-poor ones. Our results quantify in a physically motivated way the details and processes of environmental-effects-driven galaxy evolution, and might assist in analyzing hydrodynamic simulations in an observational way.

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X. Lin, J. Wang, V. Kilborn, et. al.
Thu, 20 Apr 23
54/57

Comments: 44 pages, 22 figures, 5 tables, accepted for publication in ApJ. Tables 4 and 5 are also available in machine-readable form

The First Quiescent Galaxies in TNG300 [GA]

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http://arxiv.org/abs/2304.09392


We identify the first quiescent galaxies in TNG300, the largest volume of the IllustrisTNG cosmological simulation suite, and explore their quenching processes and time evolution to z=0. We find that the first quiescent galaxies with stellar masses M_* > 3 x 10^{10} M_sun and specific star formation rates sSFR < 10^{-11} yr^{-1} emerge at z~4.2 in TNG300. Suppression of star formation in these galaxies begins with a thermal mode of AGN feedback at z~6, and a kinetic feedback mode acts in each galaxy by z~4.7 to complete the quenching process, which occurs on a time-scale of ~0.35 Gyr. Surprisingly, we find that the majority of these galaxies are not the main progenitors of their z=0 descendants; instead, four of the five galaxies fall into more massive galaxies in subsequent mergers at a range of redshifts 2.5 < z < 0.2. By z=0, these descendants are the centres of galaxy clusters with average stellar masses of 8 x 10^{11} M_sun. We make predictions for the first quenched galaxies to be located by the James Webb Space Telescope (JWST).

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A. Hartley, E. Nelson, K. Suess, et. al.
Thu, 20 Apr 23
55/57

Comments: 6 pages, 4 figures

Reionization history as a probe of primordial fluctuations [CEA]

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http://arxiv.org/abs/2304.09474


We argue that observations of the reionization history such as the luminosity function of the Lyman-$\alpha$ emitters can be used as a probe of primordial density fluctuations, particularly on small scales. Although the primordial curvature perturbations are well constrained from measurements of cosmic microwave background (CMB) anisotropies and large-scale structure, these observational data probe the curvature perturbations only on large scales, and hence its information on smaller scales will give us further insight on primordial fluctuations. Since the formation of early galaxies is sensitive to the amplitude of small-scale perturbations, and then, in turn, gives an impact on the reionization history, one can probe the primordial power spectrum on small scales through observations of reionization. In this work, we focus on the running spectral indices of the primordial power spectrum to characterize the small-scale perturbations, and investigate their constraints from observations of the luminosity function of the Lyman-$\alpha$ emitters. We show that the reionization, in combination with large-scale observations such as CMB, would be a useful tool to investigate primordial density fluctuations.

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T. Minoda, S. Yoshiura and T. Takahashi
Thu, 20 Apr 23
56/57

Comments: 20 pages, 7 figures, 2 tables. Comment welcome

Saturn's Interior After the Cassini Grand Finale [EPA]

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http://arxiv.org/abs/2304.09215


We present a review of Saturn’s interior structure and thermal evolution, with a particular focus on work in the past 5 years. Data from the Cassini mission, including a precise determination of the gravity field from the Grand Finale orbits, and the still ongoing identification of ring wave features in Saturn’s C-ring tied to seismic modes in the planet, have led to dramatic advances in our understanding of Saturn’s structure. Models that match the gravity field suggest that differential rotation, as seen in the visible atmosphere, extends down to at least a depth of 10,000 km (1/6$^{\rm th}$ the planet’s radius). At greater depths, a variety of different investigations all now point to a deep Saturn rotation rate of 10 hours and 33 minutes. There is very compelling evidence for a central heavy element concentration (“core”), that in most recent models is 12-20 Earth masses. Ring seismology strongly suggests that the core is not entirely compact, but is dilute (mixed in with the overlying H/He), and has a substantial radial extent, perhaps out to around one-half of the planet’s radius. A wide range of thermal evolution scenarios can match the planet’s current luminosity, with progress on better quantifying the helium rain scenario hampered by Saturn’s poorly known atmospheric helium abundance. We discuss the relevance of magnetic field data on understanding the planet’s current interior structure. We point towards additional future work that combines seismology and gravity within a framework that includes differential rotation, and the utility of a Saturn entry probe.

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J. Fortney, B. Militzer, C. Mankovich, et. al.
Thu, 20 Apr 23
57/57

Comments: Invited review. Accepted for publication in “Saturn: The Grand Finale”, K. H. Baines et al., eds., Cambridge University Press. All-new follow-up to previous 2016 (pre-Grand Finale) review chapter here: arXiv:1609.06324

JWST/NIRSpec Measurements of Extremely Low Metallicities in High Equivalent Width Lyman-$α$ Emitters [GA]

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http://arxiv.org/abs/2304.08511


Deep VLT/MUSE optical integral field spectroscopy has recently revealed an abundant population of ultra-faint galaxies ($M_{UV} = -$15; 0.01 $L_{\star}$) at $z=$2.9$-$6.7 due to their strong Lyman-$\alpha$ emission. The implied Lyman-$\alpha$ equivalent widths are in excess of 100-200 Angstrom, challenging existing models of normal star formation and implying extremely young ages, small stellar masses, and a very low amount of metal enrichment. We use JWST/NIRSpec’s microshutter array to follow-up 45 of these galaxies (11h in G235M/F170LP and 7h in G395M/F290LP), as well as 45 lower-equivalent width Lyman-$\alpha$ emitters. Our spectroscopy covers the range 1.7$-$5.1 micron in order to target strong optical emission lines: H$\alpha$, [OIII], H$\beta$, and [NII]. Individual measurements as well as stacks reveal line ratios consistent with a metal poor nature (2$-$30% $Z_{\odot}$) and intense ionizing radiation fields. The galaxies with the highest equivalent widths of Lyman-$\alpha$, in excess of 120 Angstrom, have lower gas-phase metallicities than those with lower equivalent widths. This implies a selection based on Lyman-$\alpha$ equivalent width is an efficient technique for identifying younger, less chemically enriched systems.

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M. Maseda, Z. Lewis, J. Matthee, et. al.
Wed, 19 Apr 23
1/58

Comments: 13 pages, 4 appendices; submitted to AAS Journals

Constraints on Europa's water group torus from HST/COS observations [EPA]

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http://arxiv.org/abs/2304.09150


In-situ plasma measurements as well as remote mapping of energetic neutral atoms around Jupiter provide indirect evidence that an enhancement of neutral gas is present near the orbit of the moon Europa. Simulations suggest that such a neutral gas torus can be sustained by escape from Europa’s atmosphere and consists primarily of molecular hydrogen, but the neutral gas torus has not yet been measured directly through emissions or in-situ. Here we present observations by the Cosmic Origins Spectrograph of the Hubble Space Telescope (HST/COS) from 2020 and 2021, which scanned the equatorial plane between 8 and 10 planetary radii west of Jupiter. No neutral gas emissions are detected. We derive upper limits on the emissions and compare these to modelled emissions from electron impact and resonant scattering using a Europa torus Monte Carlo model for the neutral gases. The comparison supports the previous findings that the torus is dilute and primarily consists of molecular hydrogen. A detection of sulfur ion emissions radially inward of the Europa orbit is consistent with emissions from the extended Io torus and with sulfur ion fractional abundances as previously detected.

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L. Roth, H. Smith, K. Yoshioka, et. al.
Wed, 19 Apr 23
2/58

Comments: N/A

JWST CEERS probes the role of stellar mass and morphology in obscuring galaxies [GA]

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http://arxiv.org/abs/2304.08517


A population of massive galaxies invisible or very faint in deep optical/near-infrared surveys, but brighter at longer wavelengths has been uncovered in the past years. However, the nature of these optically dark/faint galaxies (OFGs, among other nomenclatures) is highly uncertain. In this work, we investigate the drivers of dust attenuation in the JWST era. Particularly, we study the role of stellar mass, size, and orientation in obscuring star-forming galaxies (SFGs) at $3 < z < 7.5$, focusing on understanding why galaxies like OFGs are so faint at optical/near-infrared wavelengths. We find that stellar mass is the primary proxy of dust attenuation among those studied. Effective radius and axis ratio do not show a clear link with dust attenuation, with the effect of orientation close to random. However, there is a subset of highly dust attenuated ($A_V > 1$, typically) SFGs, of which OFGs are a specific case. For this subset, we find that the key distinctive feature is their compact size (for massive systems with $\log (M_{*}/M_{\odot}) > 10$), exhibiting 30% smaller effective radius than the average SFGs at the same stellar mass and redshift. On the contrary, they do not exhibit a preference for low axis ratios (i.e., edge-on disks). The results in this work show stellar mass as a primary proxy of dust attenuation and compact stellar light profiles behind thick dust columns obscuring typical massive SFGs.

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C. Gómez-Guijarro, B. Magnelli, D. Elbaz, et. al.
Wed, 19 Apr 23
3/58

Comments: Submitted to A&A. 13 pages, 9 figures

Joint measurement of the galaxy cluster pressure profile with Planck and SPT-SZ [CEA]

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http://arxiv.org/abs/2304.09041


We measured the average Compton profile of 461 clusters detected jointly by the South Pole Telescope (SPT) and Planck. The number of clusters included in this analysis is about one order of magnitude larger than in previous analyses. We propose an innovative method developed in Fourier space to combine optimally the Planck and SPT-SZ data, allowing us to perform a clean deconvolution of the point spread and transfer functions while simultaneously rescaling by the characteristic radial scale $R_{\rm 500}$ with respect to the critical density. The method additionally corrects for the selection bias of SPT clusters in the SPT-SZ data. We undertake a generalised Navarro-Frenk-White (NFW) fit to the profile with only one parameter fixed, allowing us to constrain the other four parameters with excellent precision. The best-fitting profile is in good agreement with the Universal Pressure Profile based on REXCESS in the inner region and with the Planck Intermediate Paper V profile based on Planck and the XMM archive in the outer region. We investigate trends with redshift and mass, finding no indication of redshift evolution but detecting a significant difference in the pressure profile of the low vs. high mass subsamples, in the sense that the low mass subsample has a profile that is more centrally-peaked than that of the high mass subsample. [abridged]

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J. Melin and G. Pratt
Wed, 19 Apr 23
4/58

Comments: 15 pages, 12 figures, submitted to A&A

Zenith-Angular Characteristics of Particles in EASs with $E_0 \simeq 10^{18}$ eV According to the Yakutsk Array Data [HEAP]

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http://arxiv.org/abs/2304.08561


Particle lateral distributions were investigated in cosmic ray air showers with energy $E_0 \simeq 10^{18}$ eV registered at the Yakutsk array with surface and underground scintillation detectors with $\simeq 1 \times \sec\theta$~GeV threshold during the period of continuous observations from 1986 to 2016. The analysis covers events with arrival direction zenith angles $\theta \le 60^{\circ}$ within five intervals with step $\Delta\cos\theta = 0.1$. Experimental values were compared to simulation results obtained with the use of CORSIKA code within the framework of QGSJet01 hadron interaction model. The whole dataset points at probable cosmic ray composition which is close to protons.

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A. Glushkov, K. Lebedev and A. Sabourov
Wed, 19 Apr 23
5/58

Comments: 14 pages, 6 figures. Accepted for publication in Physics of Atomic Nuclei, volume 86 (2023)

Two-injection scenario for the hard X-ray excess observed in Mrk 421 [HEAP]

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http://arxiv.org/abs/2304.08726


An interesting result recently reported for Mrk 421 is the detection of a significant excess at hard X-ray energies, which could provide useful information for investigating particle acceleration and emission mechanisms in the relativistic jet. Considering a two-injection scenario, we develop a self-consistent one-zone leptonic model to understand the origin of the hard X-ray excess in Mrk 421 during the period of extremely low X-ray and very high energy (VHE) flux in 2013 January. In the model, two populations of mono-energetic ultrarelativistic electrons are injected into the emission region that is a magnetized plasmoid propagating along the blazar jet. We numerically calculate the emitting electron energy distribution by solving a kinetic equation that incorporates both shock acceleration and stochastic acceleration processes. Moreover, we infer analytic expressions relating electrons acceleration, cooling, escape and injection to the observed spectra and variability. For the injection luminosity in particular, we derive a new approximate analytical expression for the case of continual injection with a mono-energetic distribution. Based on a comparison between the theoretical predictions and the observed SED, we conclude that the hard X-ray excess observed in Mrk 421 may be due to the synchrotron radiation emitted by an additional electrons population, which is co-spatial with an electron population producing simultaneous Optical/UV, soft X-ray, and $\gamma$-ray emissions. The stochastic acceleration may play a major role in producing the observed X-ray spectrum.

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W. Hu, D. Yan and Q. Hu
Wed, 19 Apr 23
6/58

Comments: 12 pages, 4 figures, 2 tables, Accepted for publication in ApJ

JADES: Insights on the low-mass end of the mass–metallicity–star-formation rate relation at $3 < z < 10$ from deep JWST/NIRSpec spectroscopy [GA]

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http://arxiv.org/abs/2304.08516


We analyse the gas-phase metallicity properties of a sample of 66 low stellar mass (log M/M_sun < 8.5) galaxies at 3<z<10, observed with JWST/NIRSpec as part of the JADES programme in its deep GOODS-S tier. By combining this sample with more massive galaxies at similar redshifts from other programmes, we study the scaling relations between stellar mass (M), oxygen abundance (O/H), and star-formation rate (SFR) across three orders of magnitude in mass out to the epoch of early galaxy assembly. We find evidence for a shallower slope at the low-mass-end of the mass-metallicity relation (MZR), with 12 + log(O/H) = (7.88 +- 0.03) + (0.17 +- 0.04) log(M/10^8 M_sun), in good agreement with the MZR probed by local analogues of high-redshift systems like green pea' andblueberry’ galaxies. The inferred slope is well matched by models including `momentum-driven’ SNe winds, suggesting that feedback mechanisms in dwarf galaxies (and at high-z) might be different from those in place at higher masses. The evolution in the normalisation is instead observed to be relatively mild compared to previous determinations of the MZR at z~3 (~0.1-0.2 dex on average). We also find a progressive deviation from the local fundamental metallicity relation (FMR) as a function of redshift, especially at z>6, with galaxies significantly less enriched (by ~0.4 dex on average) than predicted given their M and SFR. These observations are consistent with an enhanced stochasticity in the accretion rate from the cosmic web, and/or with an increased efficiency in metal removals by outflows, prompting us to reconsider the nature of the relationship between M*, O/H, and SFR in the early Universe.

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M. Curti, R. Maiolino, S. Carniani, et. al.
Wed, 19 Apr 23
7/58

Comments: Submitted to A&A. Comments are welcome

A Sun-like star orbiting a boson star [SSA]

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http://arxiv.org/abs/2304.09140


The high-precision astrometric mission GAIA recently reported the remarkable discovery of a Sun-like star closely orbiting a dark object, with a semi-major axis and period of $1.4\, \rm{AU}$ and $187.8$ days respectively. While the plausible expectation for the central dark object is a black hole, the evolutionary mechanism leading to the formation of such a two-body system is highly challenging. Here, we challenge the scenario of a central black hole and show that the observed orbital dynamics can be explained under fairly general assumptions if the central dark object is a stable clump of bosonic particles of spin-0, or spin-1, known as a boson star. We further explain how future astrometric measurements of similar systems will provide an exciting opportunity to probe the fundamental nature of compact objects and test compact alternatives to black holes.

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A. Pombo and I. Saltas
Wed, 19 Apr 23
8/58

Comments: 11 pages, 4 figures. Comments are very welcome

The Way of Water: ALMA resolves H2O emission lines in a strongly lensed dusty star-forming galaxy at z $\sim$ 3.1 [GA]

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http://arxiv.org/abs/2304.08563


We report ALMA high-resolution observations of water emission lines $p-{\rm{H_2O}} (2_{02}-1_{11}$), $o-{\rm{H_2O}} (3_{21}-3_{12})$, $p-{\rm{H_2O}} (4_{22}-4_{13})$, in the strongly lensed galaxy HATLASJ113526.2-01460 at redshift z $\sim$ 3.1. From the lensing-reconstructed maps of water emission and line profiles, we infer the general physical properties of the ISM in the molecular clouds where the lines arise. We find that the water vapor lines $o-{\rm{H_2O}} (3_{21}-3_{12})$, $p-{\rm{H_2O}} (4_{22}-4_{13})$ are mainly excited by FIR pumping from dust radiation in a warm and dense environment, with dust temperatures ranging from 70 K to $\sim 100$ K, as suggested by the line ratios. The $p-{\rm{H_2O}} (2_{02}-1_{11})$ line instead, is excited by a complex interplay between FIR pumping and collisional excitation in the dense core of the star-forming region. This scenario is also supported by the detection of the medium-level excitation of CO resulting in the line emission CO (J=8-7). Thanks to the unprecedented high resolution offered by the combination of ALMA capabilities and gravitational lensing, we discern the different phases of the ISM and locate the hot molecular clouds into a physical scale of $\sim$ 500 pc. We discuss the possibility of J1135 hosting an AGN in its accretion phase. Finally, we determine the relation between the water emission lines and the total IR luminosity of J1135, as well as the SFR as a function of water emission intensities, comparing the outcomes to local and high-$z$ galactic samples from the literature.

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F. Perrotta, M. Giulietti, M. Massardi, et. al.
Wed, 19 Apr 23
9/58

Comments: 23 pages, 13 figures, to be published in Astrophysical Journal

Cosmo-tomography toward PKS1830-211: Variability of the quasar and of its foreground molecular absorption monitored with ALMA [GA]

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http://arxiv.org/abs/2304.09002


Time variability of astronomical sources provides crude information on their typical size and on the implied physical mechanisms. PKS1830-211 is a remarkable radio-bright lensed quasar with a foreground molecular absorber at z=0.89. Small-scale morphological changes in the core-jet structure of the quasar — which is magnified by the lensing — result in a varying illumination of the absorber screen, which in turn causes variations in the absorption profile. We aim to study the time variations of the system […] in order to obtain constraints on both the quasar activity and small-scale structures in the ISM of the absorber. We used ALMA to monitor the submm continuum emission, together with the absorption spectra of the H2O and CH molecules, with 17 visits spread over six months in 2016. […] From the continuum data, we followed the evolution of the flux density, flux-density ratio, spectral index, and differential polarization between the two lensed images of the quasar; all quantities show significant variations related to the intrinsic activity of the quasar. We propose a simple parametric model of a core plus a ballistic plasmon to account for the continuum evolution, from which we constrain a time delay of 25+/-3~days between lensed images. The spectral lines reveal significant variations in the foreground absorption. A PCA highlights apparent wavy time variations, possibly linked to the helical jet precession period of the quasar. From the deep averaged spectra towards the SW image, we detect the absorption of 13CH and estimate an abundance ratio of 12CH/13CH~150. We also measure the oxygen isotopic ratios, 16O/18O=65.3+/-0.7 and 18O/17O=11.5+/-0.5. Finally, we find a remarkable continuous shallow trough in the water absorption spanning a velocity interval of nearly 500 km/s. This broad absorption could be the signature of an extra-planar molecular component. [Abridged]

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S. Muller, I. Marti-Vidal, F. Combes, et. al.
Wed, 19 Apr 23
10/58

Comments: Accepted for publication in A&A

Mapping the Skies of Ultracool Worlds: Detecting Storms and Spots with Extremely Large Telescopes [EPA]

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http://arxiv.org/abs/2304.08518


Extremely large telescopes (ELTs) present an unparalleled opportunity to study the magnetism, atmospheric dynamics, and chemistry of very low mass stars (VLMs), brown dwarfs, and exoplanets. Instruments such as the Giant Magellan Telescope – Consortium Large Earth Finder (GMT/GCLEF), the Thirty Meter Telescope’s Multi-Objective Diffraction-limited High-Resolution Infrared Spectrograph (TMT/MODHIS), and the European Southern Observatory’s Mid-Infrared ELT Imager and Spectrograph (ELT/METIS) provide the spectral resolution and signal-to-noise (S/N) necessary to Doppler image ultracool targets’ surfaces based on temporal spectral variations due to surface inhomogeneities. Using our publicly-available code, $Imber$, developed and validated in Plummer & Wang (2022), we evaluate these instruments’ abilities to discern magnetic star spots and cloud systems on a VLM star (TRAPPIST-1); two L/T transition ultracool dwarfs (VHS J1256$-$1257 b and SIMP J0136+0933); and three exoplanets (Beta Pic b and HR 8799 d and e). We find that TMT/MODHIS and ELT/METIS are suitable for Doppler imaging the ultracool dwarfs and Beta Pic b over a single rotation. Uncertainties for longitude and radius are typically $\lesssim 10^{\circ}$, and latitude uncertainties range from $\sim 10^{\circ} \ \rm{to} \ 30^{\circ}$. TRAPPIST-1’s edge-on inclination and low $\upsilon \sin i$ provide a challenge for all three instruments while GMT/GCLEF and the HR 8799 planets may require observations over multiple rotations. We compare the spectroscopic technique, photometry-only inference, and the combination of the two. We find combining spectroscopic and photometric observations can lead to improved Bayesian inference of surface inhomogeneities and offers insight into whether ultracool atmospheres are dominated by spotted or banded features.

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M. Plummer and J. Wang
Wed, 19 Apr 23
11/58

Comments: Accepted for publication in The Astrophysical Journal, 26 pages, 10 figures, 3 tables

A Cross-Internal Linear Combination Approach to Probe the Secondary CMB Anisotropies: Kinematic Sunyaev-Zel{'}dovich Effect and CMB Lensing [CEA]

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http://arxiv.org/abs/2304.09166


We propose a cross-internal linear combination (cross-ILC) approach to measure the small-scale cosmic microwave background (CMB) anisotropies robustly against the contamination from astrophysical signals. In particular, we focus on the mitigation of systematics from cosmic infrared background (CIB) and thermal Sunyaev-Zeldovich (tSZ) signals in kinematic SZ (kSZ) power spectrum and CMB lensing. We show the cross-spectrum measurement between two CMB maps created by nulling the contributions from CIB (CIB-free map) and tSZ (tSZ-free map) to be robust for kSZ as the approach significantly suppresses the total contribution of CIB and tSZ signals. Similarly, for CMB lensing, we use the approach introduced by Madhavacheril & Hill (2018) but with a slight modification by using the tSZ-free and CIB-free maps in the two legs of the quadratic estimator. By cross-correlating the CMB lensing map created using this technique with galaxy surveys, we show that the biases from both CIB/tSZ are negligible. We also compute the impact of unmodeled CIB/tSZ residuals on kSZ and cosmological parameters finding that the kSZ measured using the standard ILC to be significantly biased. The kSZ estimate from the cross-ILC remains less affected by CIB/tSZ making it crucial for CMB surveys such as the South Pole Telescope (SPT), Simons Observatory (SO) and CMB-S4. With the cross-ILC method, we find the total kSZ power spectrum can be measured at very high significance: $35\sigma$ by SPT, $22\sigma$ by SO, and $80\sigma$ by CMB-S4. We forecast constraints on the epoch of reionization using the kSZ power spectrum and find that the duration of reionization, currently unconstrained by {\it Planck}, can be constrained to $\sigma(z_{\rm dur})$= 1.5 (or) 0.5 depending on the choice of $\tau_{\rm re}$ prior. The data products and codes can be downloaded from this https://github.com/sriniraghunathan/cross_ilc_methods_paper.

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S. Raghunathan and Y. Omori
Wed, 19 Apr 23
12/58

Comments: 21 pages, 12 figures, 4 tables; Data products and the associated codes can be downloaded from this https URL; to be submitted to ApJ; Comments welcome

An Updated Dust-to-Star Geometry: Dust Attenuation Does Not Depend on Inclination in $1.3\leq z\leq 2.6$ Star-Forming Galaxies from MOSDEF [GA]

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http://arxiv.org/abs/2304.08521


We investigate dust attenuation and its dependence on viewing angle for 308 star-forming galaxies at $1.3\leq z\leq2.6$ from the MOSFIRE Deep Evolution Field (MOSDEF) survey. We divide galaxies with a detected H$\alpha$ emission line and coverage of H$\beta$ into eight groups by stellar mass, star formation rate (SFR), and inclination (i.e., axis ratio), then stack their spectra. From each stack, we measure Balmer decrement and gas-phase metallicity, then we compute median \AV and UV continuum spectral slope ($\beta$). First, we find that none of the dust properties (Balmer decrement, \AV, $\beta$) vary with axis ratio. Second, both stellar and nebular attenuation increase with increasing galaxy mass, showing little residual dependence on SFR or metallicity. Third, nebular emission is more attenuated than stellar emission, and this difference grows even larger at higher galaxy masses and SFRs. Based on these results, we propose a three-component dust model where attenuation predominantly occurs in star-forming regions and large, dusty star-forming clumps, with minimal attenuation in the diffuse ISM. In this model, nebular attenuation primarily originates in clumps, while stellar attenuation is dominated by star-forming regions. Clumps become larger and more common with increasing galaxy mass, creating the above mass trends. Finally, we argue that a fixed metal yield naturally leads to mass regulating dust attenuation. Infall of low-metallicity gas increases SFR and lowers metallicity, but leaves dust column density mostly unchanged. We quantify this idea using the Kennicutt-Schmidt and fundamental metallicity relations, showing that galaxy mass is indeed the primary driver of dust attenuation.

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B. Lorenz, M. Kriek, A. Shapley, et. al.
Wed, 19 Apr 23
13/58

Comments: 19 pages, 13 figures, accepted for publication in ApJ

Gauge/frame invariant variables for the numerical relativity study of cosmological spacetimes [CL]

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http://arxiv.org/abs/2304.07616


To numerically evolve the full Einstein equations (or modifications thereof), simulations of cosmological spacetimes must rely on a particular formulation of the field equations combined with a specific gauge/frame choice. Yet truly physical results cannot depend on the given formulation or gauge/frame choice. In this paper, we present a resolution of the gauge problem and, as an example, numerically implement it to evaluate our previous work on contracting spacetimes.

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A. Ijjas
Wed, 19 Apr 23
14/58

Comments: 22 pages, 8 figures

The Physics of Indirect Estimators of Lyman Continuum Escape and their Application to High-Redshift JWST Galaxies [GA]

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http://arxiv.org/abs/2304.08526


Reliable indirect diagnostics of LyC photon escape from galaxies are required to understand which sources were the dominant contributors to reionization. While multiple escape fraction ($f_{\rm esc}$) indicators have been proposed to trace favourable conditions for LyC leakage from the interstellar medium of low-redshift “analog” galaxies, it remains unclear whether these are applicable at high redshifts where LyC emission cannot be directly observed. Using a library of 14,120 mock spectra of star-forming galaxies with redshifts $4.64 \leq z \leq 10$ from the SPHINX$^{20}$ cosmological radiation hydrodynamics simulation, we develop a framework for the physics that leads to high $f_{\rm esc}$. We investigate LyC leakage from our galaxies based on the criteria that successful LyC escape diagnostics must \textit{i)} track a high specific star formation rate, \textit{ii)} be sensitive to stellar population age in the range $3.5-10$~Myr representing the times when supernova first explode to when LyC production significantly drops, and \textit{iii)} include a proxy for neutral gas content and gas density in the interstellar medium. ${\rm O}{32}$, $\Sigma{\rm SFR}$, M${\rm UV}$, and H$\beta$ equivalent width select for one or fewer of our criteria, rendering them either necessary but insufficient or generally poor diagnostics. In contrast, UV slope ($\beta$), and ${\rm E(B-V)}$ match two or more of our criteria, rendering them good $f{\rm esc}$ diagnostics (albeit with significant scatter). Using our library, we build a quantitative model for predicting $f_{\rm esc}$ based on $\beta$, ${\rm E(B-V)}$, H$\beta$, M${\rm UV}$, ${\rm R{23}}$, and ${\rm O_{32}}$. When applied to bright $z > 6$ Ly$\alpha$ emitters observed with JWST, we find that the majority of them have $f_{\rm esc} \lesssim 10\%$.

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N. Choustikov, H. Katz, A. Saxena, et. al.
Wed, 19 Apr 23
15/58

Comments: 16 pages, 15 figures, 1 table, submitted to MNRAS

The role of mass and environment in the build up of the quenched galaxy population since cosmic noon [GA]

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http://arxiv.org/abs/2304.09169


We conduct the first study of how the relative quenching probability of galaxies depends on environment over the redshift range $0.5 < z < 3$, using data from the UKIDSS Ultra-Deep Survey. By constructing the stellar mass functions for quiescent and post-starburst (PSB) galaxies in high, medium and low density environments to $z = 3$, we find an excess of quenched galaxies in dense environments out to at least $z \sim 2$. Using the growth rate in the number of quenched galaxies, combined with the star-forming galaxy mass function, we calculate the probability that a given star-forming galaxy is quenched per unit time. We find a significantly higher quenching rate in dense environments (at a given stellar mass) at all redshifts. Massive galaxies (M$* > 10^{10.7}$ M${\odot}$) are on average 1.7 $\pm$ 0.2 times more likely to quench per Gyr in the densest third of environments compared to the sparsest third. Finally, we compare the quiescent galaxy growth rate to the rate at which galaxies pass through a PSB phase. Assuming a visibility timescale of 500 Myr, we find that the PSB route can explain $\sim$ 50\% of the growth in the quiescent population at high stellar mass (M$* > 10^{10.7}$ M${\odot}$) in the redshift range $0.5 < z < 3$, and potentially all of the growth at lower stellar masses.

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E. Taylor, O. Almaini, M. Merrifield, et. al.
Wed, 19 Apr 23
16/58

Comments: 12 pages, 8 figures. Accepted for publication in MNRAS

The dynamical mass of the white dwarf in XY Ari questions intermediate polar X-ray spectral models [SSA]

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http://arxiv.org/abs/2304.08524


We present a dynamical study of the eclipsing intermediate polar XY Ari based on time-resolved near-infrared spectroscopy obtained with the EMIR spectrograph on the 10.4-m Gran Telescopio Canarias. Using main sequence template spectra taken with the same instrument setup as the target spectra, we measure a radial velocity amplitude of the late K-type donor star $K_2=256 \pm 2$ km s$^{-1}$. We also obtain the rotational broadening of its photospheric lines $v_\mathrm{rot} \sin i = 141 \pm 3$ km s$^{-1}$. From these and the eclipse geometry, we derive a donor-to-white dwarf mass ratio $q = M_2/M_1 = 0.62 \pm 0.02$, an orbital inclination $i = 80.8^{\circ} \pm 0.5^{\circ}$ and dynamical masses $M_{1} = 1.21 \pm 0.04 \, \mathrm{M}{\odot}$ and $M_2 = 0.75 \pm 0.04 \, \mathrm{M}{\odot}$ ($1 \sigma$). This result places the white dwarf in XY Ari as one of the three most massive known in a cataclysmic variable. Comparison with a number of white dwarf mass estimates from X-ray spectral modelling indicates the necessity of a major revision of the cooling models currently assumed for magnetic accretion in intermediate polars, as most of the X-ray white dwarf masses lie significantly below the dynamical mass value.

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A. Álvarez-Hernández, M. Torres, P. Rodríguez-Gil, et. al.
Wed, 19 Apr 23
17/58

Comments: 9 pages, 4 figures, 5 tables, submitted for publication in MNRAS

Galaxy pairs in The Three Hundred simulations II: studying bound ones and identifying them via machine learning [GA]

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http://arxiv.org/abs/2304.08898


Using the data set of The Three Hundred project, i.e. 324 hydrodynamical resimulations of cluster-sized haloes and the regions of radius 15 $h^{-1}$Mpc around them, we study galaxy pairs in high-density environments. By projecting the galaxies’ 3D coordinates onto a 2D plane, we apply observational techniques to find galaxy pairs. Based on a previous theoretical study on galaxy groups in the same simulations, we are able to classify the observed pairs into “true” or “false”, depending on whether they are gravitationally bound or not. We find that the fraction of true pairs (purity) crucially depends on the specific thresholds used to find the pairs, ranging from around 30 to more than 80 per cent in the most restrictive case. Nevertheless, in these very restrictive cases, we see that the completeness of the sample is low, failing to find a significant number of true pairs. Therefore, we train a machine learning algorithm to help us to identify these true pairs based on the properties of the galaxies that constitute them. With the aid of the machine learning model trained with a set of properties of all the objects, we show that purity and completeness can be boosted significantly using the default observational thresholds. Furthermore, this machine learning model also reveals the properties that are most important when distinguishing true pairs, mainly the size and mass of the galaxies, their spin parameter, gas content and shape of their stellar components.

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A. Contreras-Santos, A. Knebe, W. Cui, et. al.
Wed, 19 Apr 23
18/58

Comments: 20 pages, 8 figures. Published in MNRAS

Optical darkness in short-duration $γ$-ray bursts [HEAP]

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http://arxiv.org/abs/2304.09122


Gamma-ray bursts categorically produce broadband afterglow emission, but in some cases, emission in the optical band is dimmer than expected based on the contemporaneously observed X-ray flux. This phenomenon, aptly dubbed “optical darkness”, has been studied extensively in long GRBs (associated with the explosive deaths of massive stars), with possible explanations ranging from host environment extinction to high redshift to possibly unique emission mechanisms. However, investigations into optical darkness in short GRBs (associated with the mergers of compact object binaries) have thus far been limited. This work implements a procedure for determining the darkness of GRBs based on spectral indices calculated using temporally-matched Swift-XRT data and optical follow-up observations; presents a complete and up-to-date catalog of known short GRBs that exhibit optical darkness; and outlines some of the possible explanations for optically dark short GRBs. In the process of this analysis, we developed versatile and scalable data processing code that facilitates reproducibility and reuse of our pipeline. These analysis tools and resulting complete sample of dark short GRBs enable a systematic statistical study of the phenomenon and its origins, and reveal that optical darkness is indeed quite rare in short GRBs, and highly dependent on observing response time and observational effects.

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C. Gobat, A. Horst and D. Fitzpatrick
Wed, 19 Apr 23
19/58

Comments: 9 pages, 10 figures, 1 table. Accepted for publication in MNRAS