Spectroscopic age estimates for 180 000 APOGEE red-giant stars: Precise spatial and kinematic trends with age in the Galactic disc [GA]

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http://arxiv.org/abs/2304.08276


Over the last few years, many studies have found an empirical relationship between the abundance of a star and its age. Here we estimate spectroscopic stellar ages for 178 825 red-giant stars observed by the APOGEE survey with a median statistical uncertainty of 17%. To this end, we use the supervised machine learning technique XGBoost, trained on a high-quality dataset of 3 060 red-giant and red-clump stars with asteroseismic ages observed by both APOGEE and Kepler. After verifying the obtained age estimates with independent catalogues, we investigate some of the classical chemical, positional, and kinematic relationships of the stars as a function of their age. We find a very clear imprint of the outer-disc flare in the age maps and confirm the recently found split in the local age-metallicity relation. We present new and precise measurements of the Galactic radial metallicity gradient in small age bins between 0.5 and 12 Gyr, confirming a steeper metallicity gradient for 2-5 Gyr old populations and a subsequent flattening for older populations mostly produced by radial migration. In addition, we analyse the dispersion about the abundance gradient as a function of age. We find a clear power-law trend (with an exponent $\beta\approx0.15$) for this relation, indicating a smooth radial migration history in the Galactic disc over the past 7-9 Gyr. Departures from this power law are detected at ages of 8 Gyr (possibly related to the Gaia Sausage/Enceladus merger) and 2.75 Gyr (possibly related to an enhancement of the star-formation rate in the Galactic disc). Finally, we confirm previous measurements showing a steepening in the age-velocity dispersion relation at around 9 Gyr, but now extending it over a large extent of the Galactic disc (5 kpc < RGal < 13 kpc). [Abridged]

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F. Anders, P. Gispert, B. Ratcliffe, et. al.
Tue, 18 Apr 23
62/80

Comments: 14 pages + appendix, submitted to A&A. Data and analysis code available at this https URL Comments very welcome

Mapping the distribution of OB stars and associations in Auriga [SSA]

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http://arxiv.org/abs/2304.08370


OB associations are important probes of recent star formation and Galactic structure. In this study, we focus on the Auriga constellation, an important region of star formation due to its numerous young stars, star-forming regions and open clusters. We show using \textit{Gaia} data that its two previously documented OB associations, Aur OB1 and OB2, are too extended in proper motion and distance to be genuine associations, encouraging us to revisit the census of OB associations in Auriga with modern techniques. We identify 5617 candidate OB stars across the region using photometry, astrometry and our SED fitting code, grouping these into 5 high-confidence OB associations using HDBSCAN. Three of these are replacements to the historical pair of associations – Aur OB2 is divided between a foreground and a background association – while the other two associations are completely new. We connect these OB associations to the surrounding open clusters and star-forming regions, analyse them physically and kinematically, constraining their ages through a combination of 3D kinematic traceback, the position of their members in the HR diagram and their connection to clusters of known age. Four of these OB associations are expanding, with kinematic ages up to a few tens of Myr. Finally, we identify an age gradient in the region spanning several associations that coincides with the motion of the Perseus spiral arm over the last $\sim$20 Myr across the field of view.

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A. Quintana, N. Wright and R. Jeffries
Tue, 18 Apr 23
63/80

Comments: 14 pages, 12 figures, Accepted for publication in MNRAS

MASTER OT J055845.55+391533.4: SU UMa star with a dip and long rebrightening [SSA]

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http://arxiv.org/abs/2304.07695


We analyzed Asteroid Terrestrial-impact Last Alert System (ATLAS), Zwicky Transient Facility (ZTF) and All-Sky Automated Survey for Supernovae (ASAS-SN) data of MASTER OT J055845.55+391533.4 and found that this object repeats superoutburst with a dip in the middle of the outburst followed by long and sometimes oscillating rebrightening, just like a WZ Sge-type dwarf nova or an AM CVn-type object. The mean supercycle was 298(8) d, too short for a WZ Sge star, but with only a few normal outbursts. We also observed the 2023 February-March superoutburst and established the superhump period of 0.05509(2) d. This period appears to exclude the possibility of an AM CVn star. Although the 2023 observations could not detect superhumps after the dip, the 2014, 2016 and 2021 data seem to suggest that low-amplitude superhumps were present during the rebrightening phase. We note that a dip during a superoutburst is a feature common to the unusual SU UMa-type dwarf nova MASTER OT J172758.09+380021.5 during some of its superoutbursts. These objects may comprise a new class of rebrightening phenomenon in SU UMa-type dwarf novae.

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T. Kato, H. Itoh, T. Vanmunster, et. al.
Tue, 18 Apr 23
64/80

Comments: 15 pages, 8 figures, VSOLJ Variable Star Bulletin No. 113

Microwave Observations of Venus with CLASS [EPA]

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http://arxiv.org/abs/2304.07367


We report on the disk-averaged absolute brightness temperatures of Venus measured at four microwave frequency bands with the Cosmology Large Angular Scale Surveyor (CLASS). We measure temperatures of 432.3 $\pm$ 2.8 K, 355.6 $\pm$ 1.3 K, 317.9 $\pm$ 1.7 K, and 294.7 $\pm$ 1.9 K for frequency bands centered at 38.8, 93.7, 147.9, and 217.5 GHz, respectively. We do not observe any dependence of the measured brightness temperatures on solar illumination for all four frequency bands. A joint analysis of our measurements with lower frequency Very Large Array (VLA) observations suggests relatively warmer ($\sim$ 7 K higher) mean atmospheric temperatures and lower abundances of microwave continuum absorbers than those inferred from prior radio occultation measurements.

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S. Dahal, M. Brewer, A. Akins, et. al.
Tue, 18 Apr 23
65/80

Comments: 10 pages, 3 figures, submitted to PSJ

Discovery of Five Green Pea Galaxies with Double-peaked Narrow [OIII] Lines [GA]

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http://arxiv.org/abs/2304.08284


Although double-peaked narrow emission-line galaxies have been studied extensively in the past years, only a few are reported with the green pea galaxies (GPs). Here we present our discovery of five GPs with double-peaked narrow [OIII] emission lines, referred to as DPGPs, selected from the LAMOST and SDSS spectroscopic surveys. We find that these five DPGPs have blueshifted narrow components more prominent than the redshifted components, with velocity offsets of [OIII]$\lambda$5007 lines ranging from 306 to 518 $\rm km\, s^{-1}$ and full widths at half maximums (FWHMs) of individual components ranging from 263 to 441 $\rm km\, s^{-1}$. By analyzing the spectra and the spectral energy distributions (SEDs), we find that they have larger metallicities and stellar masses compared with other GPs. The H$\alpha$ line width, emission-line diagnostic, mid-infrared color, radio emission, and SED fitting provide evidence of the AGN activities in these DPGPs. They have the same spectral properties of Type 2 quasars. Furthermore, we discuss the possible nature of the double-peaked narrow emission-line profiles of these DPGPs and find that they are more likely to be dual AGN. These DPGP galaxies are ideal laboratories for exploring the growth mode of AGN in the extremely luminous emission-line galaxies, the co-evolution between AGN and host galaxies, and the evolution of high-redshift galaxies in the early Universe.

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R. Lin, Z. Zheng, J. Wang, et. al.
Tue, 18 Apr 23
66/80

Comments: 12 pages, 8 figues, 3 tables; Comments welcome!

On the hosts of neutron star mergers in the nearby Universe [GA]

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http://arxiv.org/abs/2304.08129


Recently, the characterisation of binary systems of neutron stars has become central in various fields such as gravitational waves, gamma-ray bursts (GRBs), and the chemical evolution of galaxies. In this work, we explore possible observational proxies that can be used to infer some characteristics of the delay time distribution (DTD) of neutron star mergers (NSMs). We construct a sample of model galaxies that fulfils the observed galaxy stellar mass function, star formation rate versus mass relation, and the cosmic star formation rate density. The star formation history of galaxies is described with a log-normal function characterised by two parameters: the position of the maximum and the width of the distribution. We assume a theoretical DTD that mainly depends on the lower limit and the slope of the distribution of the separations of the binary neutron stars systems at birth. We find that the current rate of NSMs ($\mathcal{R}=320^{+490}_{-240}$ Gpc$^{-3}$yr$^{-1}$) requires that $\sim0.3$ per cent of neutron star progenitors lives in binary systems with the right characteristics to lead to a NSM within a Hubble time. We explore the expected relations between the rate of NSMs and the properties of the host galaxy. We find that the most effective proxy for the shape of the DTD of NSMs is the current star formation activity of the typical host. At present, the fraction of short-GRBs observed in star-forming galaxies favours DTDs with at least $\sim40\%$ of mergers within $100$ Myr. This conclusion will be put on a stronger basis with larger samples of short-GRBs with host association (e.g. $600$ events at $z \leq 1$)

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L. Cavallo and L. Greggio
Tue, 18 Apr 23
67/80

Comments: 20 pages, 18 Figures, To appear on MNRAS

Light cold dark matter from non-thermal decay [CL]

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http://arxiv.org/abs/2304.07462


We investigate the mass range and the corresponding free-streaming length scale of dark matter produced non-thermally from decay of heavy objects which can be either dominant or sub-dominant at the moment of decay. We show that the resulting dark matter could be very light well below keV scale with a free-streaming length satisfying the Lyman-{\alpha} constraints. We demonstrate two explicit examples for such light cold dark matter.

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K. Choi, J. Gong, J. Joh, et. al.
Tue, 18 Apr 23
68/80

Comments: 8 pages, 4 figures

Mock X-ray observations of hot gas with L-Galaxies semi-analytic models of galaxy formation [GA]

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http://arxiv.org/abs/2304.08010


We create mock X-ray observations of hot gas in galaxy clusters with a new extension of L-Galaxies semi-analytic model of galaxy formation, which includes the radial distribution of hot gas in each halo. Based on the model outputs, we first build some mock light cones, then generate mock spectra with SOXS package and derive the mock images in the light cones. Using the mock data, we simulate the mock X-ray spectra for ROSAT all-sky survey, and compare the mock spectra with the observational results. Then, we consider the design parameters of HUBS mission and simulate the observation of the halo hot gas for HUBS as an important application of our mock work. We find: (1) Our mock data match the observations by current X-ray telescopes. (2) The survey of hot baryons in resolved clusters by HUBS is effective below redshift 0.5, and the observations of the emission lines in point-like sources at z>0.5 by HUBS help us understand the hot baryons in the early universe. (3) By taking the advantage of the large simulation box and flexibility in semi-analytic models, our mock X-ray observations provide the opportunity to make target selection and observation strategies for forthcoming X-ray facilities.

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W. Zhong, J. Fu, S. Shiyin, et. al.
Tue, 18 Apr 23
69/80

Comments: 15 pages, 11 figures

Climatologies of Various OH Lines From About 90,000 X-shooter Spectra [CL]

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http://arxiv.org/abs/2304.08206


The nocturnal mesopause region of the Earth’s atmosphere radiates chemiluminescent emission from various roto-vibrational bands of hydroxyl (OH), which is therefore a good tracer of the chemistry and dynamics at the emission altitudes. Intensity variations can, e.g., be caused by the general circulation, gravity waves, tides, planetary waves, and the solar activity. While the basic OH response to the different dynamical influences has been studied quite frequently, detailed comparisons of the various individual lines are still rare. Such studies can improve our understanding of the OH-related variations as each line shows a different emission profile. We have therefore used about 90,000 spectra of the X-shooter spectrograph of the Very Large Telescope at Cerro Paranal in Chile in order to study 10 years of variations of 298 OH lines. The analysis focuses on climatologies of intensity, solar cycle effect, and residual variability (especially with respect to time scales of hours and about 2 days) for day of year and local time. For a better understanding of the resulting variability patterns and the line-specific differences, we applied decomposition techniques, studied the variability depending on time scale, and calculated correlations. As a result, the mixing of thermalized and nonthermalized OH level populations clearly influences the amplitude of the variations. Moreover, the local times of the variability features shift depending on the effective line emission height, which can mainly be explained by the propagation of the migrating diurnal tide. This behavior also contributes to remarkable differences in the effective solar cycle effect.

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S. Noll, C. Schmidt, W. Kausch, et. al.
Tue, 18 Apr 23
70/80

Comments: 35 single-column pages and 12 figures; accepted for publication in J. Geophys. Res. Atmos

Far-infrared line emission from the outer Galaxy cluster Gy 3-7 with SOFIA/FIFI-LS: Physical conditions and UV fields [GA]

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http://arxiv.org/abs/2304.08127


(abridged) Far-infrared (FIR) line emission provides key information about the gas cooling and heating due to shocks and UV radiation associated with the early stages of star formation. Gas cooling via FIR lines might, however, depend on metallicity. We aim to quantify the FIR line emission and determine the spatial distribution of the CO rotational temperature, ultraviolet (UV) radiation field, and H2 number density toward the embedded cluster Gy 3-7 in the CMa-l224 star-forming region, whose metallicity is expected to be intermediate between that of the LMC and the Solar neighborhood. By comparing the total luminosities of CO and [O I] toward Gy 3-7 with values found for low- and high-mass protostars extending over a broad range of metallicities, we also aim to identify the possible effects of metallicity on the FIR line cooling within our Galaxy. We studied SOFIA/FIFI-LS spectra of Gy 3-7 covering several FIR lines. The spatial extent of CO high-J (J>14) emission resembles that of the elongated 160 um continuum emission detected with Herschel. The CO transitions from J=14-13 to J=16-15 are detected throughout the cluster and show a median rotational temperature of 170+/-30 K on Boltzmann diagrams. Comparisons to other protostars observed with Herschel show a good agreement with intermediate-mass sources in the inner Galaxy. Assuming an origin of the [O I] and high-J CO emission in UV-irradiated C-shocks, we obtained pre-shock H2 number densities of 10^4-5 cm-3 and UV radiation field strengths of 0.1-10 Habing fields. Far-IR line observations reveal ongoing star formation in Gy 3-7, dominated by intermediate-mass Class 0/I young stellar objects. The ratio of molecular-to-atomic far-IR line emission shows a decreasing trend with bolometric luminosities of the protostars. However, it does not indicate that the low-metallicity has an impact on the line cooling in Gy 3-7.

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N. Le, A. Karska, M. Figueira, et. al.
Tue, 18 Apr 23
71/80

Comments: 26 pages, 23 figures

Outflows in the Gaseous Discs of Active Galaxies and their impact on Black Hole Scaling Relations [GA]

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http://arxiv.org/abs/2304.08273


To tackle the still unsolved and fundamental problem of the role of Active Galactic Nuclei (AGN) feedback in shaping galaxies, in this work we implement a new physical treatment of AGN-driven winds into our semi-analytic model of galaxy formation. To each galaxy in our model, we associate solutions for the outflow expansion and the mass outflow rates in different directions, depending on the AGN luminosity, on the circular velocity of the host halo, and on gas content of the considered galaxy. To each galaxy we also assign an effective radius derived from energy conservation during merger events, and a stellar velocity dispersion self-consistently computed via Jeans modelling. We derive all the main scaling relations between Black hole (BH) mass and total/bulge stellar mass, velocity dispersion, host halo dark matter mass, and star formation efficiency. We find that our improved AGN feedback mostly controls the dispersion around the relations but plays a subdominant role in shaping slopes and/or normalizations of the scaling relations. Including possible limited-resolution selection biases in the model provides better agreement with the available data. The model does not point to any more fundamental galactic property linked to BH mass, with velocity dispersion playing a similar role with respect to stellar mass, in tension with present data. In line with other independent studies carried out on comprehensive semi-analytic and hydrodynamic galaxy-BH evolution models, our current results signal either an inadequacy of present cosmological models of galaxy formation in fully reproducing the local scaling relations, in terms of both shape and residuals, and/or point to an incompleteness issue affecting the local sample of dynamically-measured BHs.

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N. Menci, F. Fiore, F. Shankar, et. al.
Tue, 18 Apr 23
72/80

Comments: 21 pages, accepted for publications in Astronomy & Astrophysics

Constraints on the proton fraction of cosmic rays at the highest energies and the consequences for cosmogenic neutrinos and photons [HEAP]

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http://arxiv.org/abs/2304.07321


Over the last decade, observations have shown that the mean mass of ultra-high-energy cosmic rays (UHECRs) increases progressively toward the highest energies. However, the precise composition is still unknown, and several theoretical studies hint at the existence of a subdominant proton component up to the highest energies. Motivated by the exciting prospect of performing charged-particle astronomy with ultra-high-energy (UHE) protons we quantify the level of UHE-proton flux that is compatible with present multimessenger observations and the associated fluxes of neutral messengers produced in the interactions of the protons. We study this scenario with numerical simulations of two independent populations of extragalactic sources and perform a fit to the combined UHECR energy spectrum and composition observables, constrained by diffuse gamma-ray and neutrino observations. We find that up to of order $10\%$ of the cosmic rays at the highest energies can be UHE protons, although the result depends critically on the selected hadronic interaction model for the air showers. Depending on the maximum proton energy ($E_\text{max}^\text{p}$) and the redshift evolution of sources, the associated flux of cosmogenic neutrinos and UHE gamma rays can significantly exceed the multimessenger signal of the mixed-mass cosmic rays. Moreover, if $E_\text{max}^\text{p}$ is above the GZK limit, we predict a large flux of UHE neutrinos above EeV energies that is absent in alternate scenarios for the origin of UHECRs. We present the implications and opportunities afforded by these UHE proton, neutrino and photon fluxes for future multimessenger observations.

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D. Ehlert, A. Vliet, F. Oikonomou, et. al.
Tue, 18 Apr 23
73/80

Comments: 11 pages, 8 figures, 3 tables. Comments welcome

Evidence for a black hole spin–orbit misalignment in the X-ray binary Cyg X-1 [HEAP]

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http://arxiv.org/abs/2304.07553


Cyg X-1 is probably the most studied and best understood black-hole X-ray binary. Recently, its accretion geometry has been probed with the X-ray polarization. The position angle of the X-ray emitting flow was found to be aligned with the position angle of the radio jet in the plane of the sky. At the same time, the observed high polarization degree could be obtained only for a high inclination of the X-ray emitting flow, indicating a misalignment between the binary axis and the black hole spin. The jet, in turn, is believed to be directed by the spin axis, hence similar misalignment is expected between the jet and binary axes. We test this hypothesis using very long (up to about 26 years) multi-band radio observations. We find the misalignment of $20^\circ$-$30^\circ$; however, on the contrary to the earlier expectations, the misalignment lies in the plane of the sky and not along the line of sight. Furthermore, the presence of the misalignment questions our understanding of the evolution of this binary system.

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A. Zdziarski, A. Veledina, M. Szanecki, et. al.
Tue, 18 Apr 23
74/80

Comments: 16 pages, 5 figures

Properties of First-Order Hadron-Quark Phase Transition from Directly Inverting Neutron Star Observables [CL]

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http://arxiv.org/abs/2304.07381


By directly inverting the observational data of several neutron star observables in the three dimensional parameter space of the constant speed of sound (CSS) model while fixing all hadronic Equation of State parameters at their currently known most probable values, we constrain the three parameters of the CSS model and their correlations. Using two lower radius limits of $R_{2.01}=11.41$ km and $R_{2.01}=12.2$ km for PSR J0740+6620 obtained from two independent analyses using different approaches by the Neutron Star Interior Composition Explorer (NICER) Collaboration, the speed of sound squared $c_{\rm QM}^2$ in quark matter is found to have a lower limit of $0.35$ and $0.43$ in unit of $c^2$, respectively, above its conformal limit of $c_{\rm QM}^2<1/3$. Moreover, an approximately linear correlation between the first-order hadron-quark transition density $\rho_t$ and its strength $\Delta\varepsilon$ is found.

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N. Zhang and B. Li
Tue, 18 Apr 23
75/80

Comments: 7 pages with 4 figures

A Near-Infrared Faint, Far-Infrared-Luminous Dusty Galaxy at z~5 in COSMOS-Web [GA]

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http://arxiv.org/abs/2304.07316


A growing number of far-infrared bright sources completely invisible in deep extragalactic optical surveys hint at an elusive population of z>4 dusty, star-forming galaxies. Cycle 1 JWST surveys are now detecting their rest-frame optical light, which provides key insight into their stellar properties and statistical constraints on the population as a whole. This work presents the JWST/NIRCam counterpart from the COSMOS-Web survey to a far-infrared SCUBA-2 and ALMA source, AzTECC71, which was previously undetected at wavelengths shorter than 850 microns. AzTECC71, amongst the reddest galaxies in COSMOS-Web with F277W – F444W~0.9, is undetected in NIRCam/F150W and F115W and fainter in F444W than other sub-millimeter galaxies identified in COSMOS-Web by 2-4 magnitudes. This is consistent with the system having both a lower stellar mass and higher redshift than the median dusty, star-forming galaxy. With deep ground- and space-based upper limits combined with detections in F277W, F444W and the far-IR including ALMA Band 6, we find a high probability (99%) that AzTECC71 is at z>4 with z_phot=5.7(+0.8,-0.7). This galaxy is massive (logM*/Msun~10.7) and IR-luminous (logLIR/Lsun~12.7), comparable to other optically-undetected but far-IR bright dusty, star-forming galaxies at z>4. This population of luminous, infrared galaxies at z>4 is largely unconstrained but comprises an important bridge between the most extreme dust-obscured galaxies and more typical high-redshift star-forming galaxies. If further far-IR-selected galaxies that drop out of the F150W filter in COSMOS-Web have redshifts z>4 like AzTECC71, then the volume density of such sources may be ~3-10x greater than previously estimated.

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J. McKinney, S. Manning, O. Cooper, et. al.
Tue, 18 Apr 23
76/80

Comments: 13 pages, 7 figures, submitted to ApJ

GREX-PLUS Science Book [CEA]

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http://arxiv.org/abs/2304.08104


GREX-PLUS (Galaxy Reionization EXplorer and PLanetary Universe Spectrometer) is a mission candidate for a JAXA’s strategic L-class mission to be launched in the 2030s. Its primary sciences are two-fold: galaxy formation and evolution and planetary system formation and evolution. The GREX-PLUS spacecraft will carry a 1.2 m primary mirror aperture telescope cooled down to 50 K. The two science instruments will be onboard: a wide-field camera in the 2-8 $\mu$m wavelength band and a high resolution spectrometer with a wavelength resolution of 30,000 in the 10-18 $\mu$m band. The GREX-PLUS wide-field camera aims to detect the first generation of galaxies at redshift $z>15$. The GREX-PLUS high resolution spectrometer aims to identify the location of the water “snow line” in proto-planetary disks. Both instruments will provide unique data sets for a broad range of scientific topics including galaxy mass assembly, origin of supermassive blackholes, infrared background radiation, molecular spectroscopy in the interstellar medium, transit spectroscopy for exoplanet atmosphere, planetary atmosphere in the Solar system, and so on.

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G. Team, A. Inoue, Y. Harikane, et. al.
Tue, 18 Apr 23
77/80

Comments: This document is the first version of a collection of scientific themes which can be achieved with GREX-PLUS. Each section in Chapters 2 and 3 is based on the presentation at the GREX-PLUS Science Workshop held on 24-25 March, 2022 at Waseda University

The Gaia-ESO Survey: homogenisation of stellar parameters and elemental abundances [SSA]

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http://arxiv.org/abs/2304.07720


The Gaia-ESO Survey is a public spectroscopic survey that has targeted $\gtrsim10^5$ stars covering all major components of the Milky Way from the end of 2011 to 2018, delivering its public final release in May 2022. Unlike other spectroscopic surveys, Gaia-ESO is the only survey that observed stars across all spectral types with dedicated, specialised analyses: from O ($T_\mathrm{eff} \sim 30,000-52,000$~K) all the way to K-M ($\gtrsim$3,500~K). The physics throughout these stellar regimes varies significantly, which has previously prohibited any detailed comparisons between stars of significantly different type. In the final data release (internal data release 6) of the Gaia-ESO Survey, we provide the final database containing a large number of products such as radial velocities, stellar parameters and elemental abundances, rotational velocity, and also, e.g., activity and accretion indicators in young stars and membership probability in star clusters for more than 114,000 stars. The spectral analysis is coordinated by a number of Working Groups (WGs) within the Survey, which specialise in the various stellar samples. Common targets are analysed across WGs to allow for comparisons (and calibrations) amongst instrumental setups and spectral types. Here we describe the procedures employed to ensure all Survey results are placed on a common scale to arrive at a single set of recommended results for all Survey collaborators to use. We also present some general quality and consistency checks performed over all Survey results.

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A. Hourihane, P. Francois, C. Worley, et. al.
Tue, 18 Apr 23
78/80

Comments: A&A accepted, minor revision, 36 pages, 38 figures

A statistical model of stellar variability. I. FENRIR: a physics-based model of stellar activity, and its fast Gaussian process approximation [SSA]

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http://arxiv.org/abs/2304.08489


The detection of terrestrial planets by radial velocity and photometry is hindered by the presence of stellar signals. Those are often modeled as stationary Gaussian processes, whose kernels are based on qualitative considerations, which do not fully leverage the existing physical understanding of stars. Our aim is to build a formalism which allows to transfer the knowledge of stellar activity into practical data analysis methods. In particular, we aim at obtaining kernels with physical parameters. This has two purposes: better modelling signals of stellar origin to find smaller exoplanets, and extracting information about the star from the statistical properties of the data. We consider several observational channels such as photometry, radial velocity, activity indicators, and build a model called FENRIR to represent their stochastic variations due to stellar surface inhomogeneities. We compute analytically the covariance of this multi-channel stochastic process, and implement it in the S+LEAF framework to reduce the cost of likelihood evaluations from $O(N^3)$ to $O(N)$. We also compute analytically higher order cumulants of our FENRIR model, which quantify its non-Gaussianity. We obtain a fast Gaussian process framework with physical parameters, which we apply to the HARPS-N and SORCE observations of the Sun, and constrain a solar inclination compatible with the viewing geometry. We then discuss the application of our formalism to granulation. We exhibit non-Gaussianity in solar HARPS radial velocities, and argue that information is lost when stellar activity signals are assumed to be Gaussian. We finally discuss the origin of phase shifts between RVs and indicators, and how to build relevant activity indicators. We provide an open-source implementation of the FENRIR Gaussian process model with a Python interface.

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N. Hara and J. Delisle
Tue, 18 Apr 23
79/80

Comments: Submitted to Astronomy \& Astrophysics

Search for X-ray Quasi-periodicity of six AGNs using Gaussian Process method [HEAP]

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http://arxiv.org/abs/2304.08044


The quasi-periodic oscillations (QPOs) found in active galactic nuclei (AGNs) are a very interesting observational phenomenon implying an unknown physical mechanism around supermassive black holes. Several AGNs have been found to have QPO phenomena in the X-ray energy band. Long-duration X-ray observations were collected and reduced for six AGNs with a suspected QPO. The Gaussian process (GP) model celerite was used to fit the light curves and to search for the quasi-periodicity behavior. The power spectral density and parameter posterior distributions of each light curve were calculated with the optimal model. Of the six AGNs, only RE J1034+396 was found to have a QPO of about 3600 s. The other five sources do not show QPO modulation behavior. We propose that a hot spot on the accretion disk is a possible physical mechanism resulting in this quasi-periodic behavior of AGNs.

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H. Zhang, S. Yang and B. Dai
Tue, 18 Apr 23
80/80

Comments: 20 pages, 12 figures, accepted for publication in ApJ

Physical and chemical complexity in high-mass star-forming regions with ALMA. I. Overview and evolutionary trends of physical properties [GA]

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http://arxiv.org/abs/2304.07237


In this study, we investigate how physical properties, such as the density and temperature profiles, evolve on core scales through the evolutionary sequence during high-mass star formation ranging from protostars in cold infrared dark clouds to evolved UCHII regions. We observed 11 high-mass star-forming regions with ALMA at 3 mm wavelengths. Based on the 3 mm continuum morphology and recombination line emission, tracing locations with free-free (ff) emission, the fragmented cores analyzed in this study are classified into either dust or dust+ff cores. In addition, we resolve three cometary UCHII regions with extended 3 mm emission that is dominated by free-free emission. The temperature structure and radial profiles (T~r^-q ) are determined by modeling molecular emission of CH3CN and CH313CN with XCLASS and by using the HCN-to- HNC intensity ratio as probes for the gas kinetic temperature. The density profiles (n~r^-p ) are estimated from the 3 mm continuum visibility profiles. The masses M and H2 column densities N(H2) are then calculated from the 3 mm dust continuum emission. Results. We find a large spread in mass and peak H2 column density in the detected sources ranging from 0.1-150 Msun and 10^23 – 10^26 cm-2 , respectively. Including the results of the CORE and CORE-extension studies (Gieser et al. 2021, 2022) to increase the sample size, we find evolutionary trends on core scales for the temperature power-~law index q increasing from 0.1 to 0.7 from infrared dark clouds to UCHII regions, while for the the density power-law index p on core scales, we do not find strong evidence for an evolutionary trend. However, we find that on the larger clump scales throughout these evolutionary phases the density profile flattens from p = 2.2 to p = 1.2. (abridged)

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C. Gieser, H. Beuther, D. Semenov, et. al.
Mon, 17 Apr 23
1/51

Comments: 21 pages, 10 figures, submitted to A&A

How the Moon Impacts Subsea Communication Cables [CL]

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http://arxiv.org/abs/2304.06905


We report tidal-induced latency variations on a transpacific subsea cable. Week-long recordings with a precision phase meter suggest length changes in the sub-meter range caused by the Poisson effect. The described method adds to the toolbox for the new field >>optical oceanic seismology<<.

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L. Moeller
Mon, 17 Apr 23
2/51

Comments: N/A

Signatures of Cosmic Ray Heating in 21-cm Observables [CEA]

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http://arxiv.org/abs/2304.07201


Cosmic rays generated by supernovae carry away a significant portion of the lifetime energy emission of their parent star, making them a plausible mechanism for heating the early universe intergalactic medium (IGM). Following a review of the existing literature on cosmic ray heating, we develop a flexible model of this heating mechanism for use in semi-numerical 21-cm signal simulations and conduct the first investigations of the signatures it imprints on the 21-cm power spectrum and tomographic maps. We find that cosmic ray heating of the IGM is short-ranged, leading to heating clustered around star-forming sites, and a sharp contrast between heated regions of 21-cm emission and unheated regions of absorption. This contrast results in greater small-scale power for cosmic ray heated scenarios compared to what is found for X-ray heating, thus suggesting a way to test the nature of IGM heating with future 21-cm observations. Finally, we find an unexpectedly rich thermal history in models where cosmic rays can only escape efficiently from low-mass halos, such as in scenarios where these energetic particles originate from population III star supernovae remnants. The interplay of heating and the Lyman-Werner feedback in these models can produce a local peak in the IGM kinetic temperature and, for a limited parameter range, a flattened absorption trough in the global 21-cm signal.

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T. Gessey-Jones, A. Fialkov, E. Acedo, et. al.
Mon, 17 Apr 23
3/51

Comments: 21 pages, 10 figures. Submitted to MNRAS

Radio Galaxy Zoo EMU: Towards a Semantic Radio Galaxy Morphology Taxonomy [GA]

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http://arxiv.org/abs/2304.07171


We present a novel natural language processing (NLP) approach to deriving plain English descriptors for science cases otherwise restricted by obfuscating technical terminology. We address the limitations of common radio galaxy morphology classifications by applying this approach. We experimentally derive a set of semantic tags for the Radio Galaxy Zoo EMU (Evolutionary Map of the Universe) project and the wider astronomical community. We collect 8,486 plain English annotations of radio galaxy morphology, from which we derive a taxonomy of tags. The tags are plain English. The result is an extensible framework which is more flexible, more easily communicated, and more sensitive to rare feature combinations which are indescribable using the current framework of radio astronomy classifications.

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M. Bowles, H. Tang, E. Vardoulaki, et. al.
Mon, 17 Apr 23
4/51

Comments: 17 pages, 11 Figures, Accepted at MNRAS

Anatomy of parameter-estimation biases in overlapping gravitational-wave signals [IMA]

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http://arxiv.org/abs/2304.06734


In future gravitational-wave (GW) detections, a large number of overlapping GW signals will appear in the data stream of detectors. When extracting information from one signal, the presence of other signals can cause large parameter estimation biases. Using the Fisher matrix (FM), we develop a bias analysis procedure to investigate how each parameter of other signals affects the inference biases. Taking two-signal overlapping as an example, we show detailedly and quantitatively that the biases essentially originate from the overlapping of the frequency evolution. Furthermore, we find that the behaviors of the correlation coefficients between the parameters of the two signals are similar to the biases. Both of them can be used as characterization of the influence between signals. We also corroborate the bias results of the FM method with full Bayesian analysis. Our results provide powerful guidance for parameter estimation, and the analysis methodology is easy to generalize.

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Z. Wang, D. Liang, J. Zhao, et. al.
Mon, 17 Apr 23
5/51

Comments: 29 pages, 13 figures

Diffusion Coefficients of $^{56}$Fe in C-O and O-Ne White Dwarfs [SSA]

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http://arxiv.org/abs/2304.07228


The diffusion coefficients of neutron rich nuclei in crystallizing white dwarf (WD) stars are essential microphysics input for modeling the evolution of the composition profile. Recently, molecular dynamics simulations have been used to compute diffusion coefficients for realistic mixtures of C-O and O-Ne WDs with many trace nuclides that could be important sedimentary heat sources such as $^{22}$Ne, $^{23}$Na, $^{25}$Mg, and $^{27}$Mg. In this brief note, I repeat these simulations but now include $^{56}$Fe. I find that for the large charge ratios involved in these mixtures the empirical law developed in our earlier work tends to under-predict diffusion coefficients in the moderately coupled regime by 30 to 40 percent. As this formalism is presently implemented in the stellar evolution code MESA, it is important for authors studying mixtures containing heavy nuclides like $^{56}$Fe to be aware of these systematics. However, the impact on astrophysics is expected to be small.

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M. Caplan
Mon, 17 Apr 23
6/51

Comments: 3 pages, 1 figure, submitted to RNAAS

Sweeping Horndeski Canvas: New Growth-Rate Parameterization for Modified-Gravity Theories [CEA]

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http://arxiv.org/abs/2304.07281


We propose and numerically validate a new fitting formula that is sufficiently accurate to model the growth of structure in Horndeski theories of modified gravity for upcoming Stage IV and V large-scale structure surveys. Based on an analysis of more than 18,000 Horndeski models and adopting the popular parameterization of the growth rate $f(z) = \Omega_{M}(z)^{\gamma}$, we generalize the constant growth index $\gamma$ to a two-parameter redshift-dependent quantity, $\gamma(z)$, that more accurately fits these models. We demonstrate that the functional form $\gamma(z)=\gamma_0+\gamma_1z^2 / (1+z)$ improves the median $\chi^2$ of the fit to viable Horndeski models by a factor of $\sim40$ relative to that of a constant $\gamma$, and is sufficient to obtain unbiased results even for precise measurements expected in Stage IV and V surveys. Finally, we constrain the parameters of the new fitting formula using current cosmological data.

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Y. Wen, N. Nguyen and D. Huterer
Mon, 17 Apr 23
7/51

Comments: 23 pages, 6 figures

Revisiting multiwavelength data on the supersoft X-ray source CAL 83 [HEAP]

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http://arxiv.org/abs/2304.06804


In this study we revisit public data on the supersoft X-ray source CAL 83 in the Large Magellanic Cloud. A significant part of our analysis is focused on XMM-Newton X-ray observations, in which updated data reduction procedures and quality assessment were applied. We report on the capability of publicly available hot atmosphere models in describing the source’s soft X-ray spectrum. By gathering historical flux measurements in multiple wavelengths and comparing them with the fluxes derived from the X-ray analysis, we find that a $\sim$ 360 kK phenomenological blackbody model describes the spectral energy distribution of CAL 83 fairly well. We also retrieve data from the XMM-Newton UV/optical camera, which is co-alligned with the X-ray instruments and provides strictly simultaneous measurements. These observations demonstrate that the X-ray emission is definitely anti-correlated with emission at longer wavelengths in a time-scale of days to weeks. A closer look at simultaneous X-ray and UV count rates in single light curves reveals that the anti-correlated behaviour is actually present in time scales as short as minutes, suggesting that the origin of variable emission in the system is not unique.

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P. Stecchini, M. Diaz, F. D’Amico, et. al.
Mon, 17 Apr 23
8/51

Comments: 9 pages, 8 figures. To be published in MNRAS

Hunting the stochastic gravitational wave background in pulsar timing array cross correlations through theoretical uncertainty [CL]

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http://arxiv.org/abs/2304.07040


Incredible progress on the theoretical uncertainty of the spatial correlations of the stochastic gravitational wave (GW) background were recently made. However, it remains to realize the impact of this theoretical uncertainty on PTA cross correlations analysis. This paper pushes forward in this direction, as a proof–of–principle: showing the potential role that theoretical uncertainty has on unburying the stochastic GW background signal in noisy PTA cross correlation measurements. We consider both a mock data set and the noise–marginalized 12.5 years NANOGrav spatial correlation measurements, and find optimistic conclusions regardless of the physical content of the GW background and the nature of the noise in the data. Very briefly, we show through various cases a modest, but profound result that looking out for a stochastic signal is better when two of its moments are utilized. Or, in terms of GWs, we show that the theoretical uncertainty can play a substantial role in the hunt for the stochastic GW background.

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R. Bernardo and K. Ng
Mon, 17 Apr 23
9/51

Comments: 7 pages + refs, 3 figures, comments welcome

Shaken or stirred: the diffuse interstellar medium with exceptionally high SiO abundance [GA]

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http://arxiv.org/abs/2304.06741


Interstellar shocks, a key element of stellar feedback processes, shape the structure of the interstellar medium (ISM) and are essential for the chemistry, thermodynamics, and kinematics of interstellar gas. Powerful, high-velocity shocks are driven by stellar winds, young supernova explosions, more evolved supernova remnants, cloud-cloud collisions, and protostellar outflows, whereas the existence and origin of much-lower-velocity shocks ($\lesssim $ 10 km$~$s$^{-1}$) are not understood. Direct observational evidence for interstellar shocks in diffuse and translucent ISM environments have been especially lacking. We present the most sensitive survey to date of SiO — often considered an unambiguous tracer of interstellar shocks — in absorption, obtained with the Northern Extended Millimeter Array interferometer. We detect SiO in 5/8 directions probing diffuse and translucent environments without ongoing star formation. Our results demonstrate that SiO formation in the diffuse ISM (i.e., in the absence of significant star formation and stellar feedback) is more widespread and effective than previously reported. The observed SiO linewidths are all $\lesssim$ 4 km$~$s$^{-1}$, excluding high-velocity shocks as a formation mechanism. Yet, the SiO abundances we detect are mostly 1 to 2 orders of magnitude higher than typically assumed in quiescent environments and are often accompanied with other molecular transitions whose column densities cannot be explained with UV-dominated chemical models. Our results challenge the traditional view of SiO production via stellar-feedback sources and emphasize the need for observational constraints on the distribution of Si in the gas phase and grain mantles, which are crucial for understanding the physics of grain processing and diffuse interstellar chemistry.

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D. Rybarczyk, S. Stanimirovic and A. Gusdorf
Mon, 17 Apr 23
10/51

Comments: 19 pages, 6 figures. Accepted to ApJ

Investigating Gaia EDR3 parallax systematics using asteroseismology of Cool Giant Stars observed by Kepler, K2, and TESS I. Asteroseismic distances to 12,500 red-giant stars [SSA]

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http://arxiv.org/abs/2304.07158


Gaia EDR3 has provided unprecedented data that generate a lot of interest in the astrophysical community, despite the fact that systematics affect the reported parallaxes at the level of ~ 10 muas. Independent distance measurements are available from asteroseismology of red-giant stars with measurable parallaxes, whose magnitude and colour ranges more closely reflect those of other stars of interest. In this paper, we determine distances to nearly 12,500 red-giant branch and red clump stars observed by Kepler, K2, and TESS. This is done via a grid-based modelling method, where global asteroseismic observables, constraints on the photospheric chemical composition, and on the unreddened photometry are used as observational inputs. This large catalogue of asteroseismic distances allows us to provide a first comparison with Gaia EDR3 parallaxes. Offset values estimated with asteroseismology show no clear trend with ecliptic latitude or magnitude, and the trend whereby they increase (in absolute terms) as we move towards redder colours is dominated by the brightest stars. The correction model proposed by Lindegren et al. (2021) is not suitable for all the fields considered in this study. We find a good agreement between asteroseismic results and model predictions of the red clump magnitude. We discuss possible trends with the Gaia scan law statistics, and show that two magnitude regimes exist where either asteroseismology or Gaia provides the best precision in parallax.

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S. Khan, A. Miglio, E. Willett, et. al.
Mon, 17 Apr 23
11/51

Comments: 11 pages, 8 figures, Accepted for publication in A&A

The power spectrum of extended [C II] halos around high redshift galaxies [GA]

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http://arxiv.org/abs/2304.07023


ALMA observations have detected extended ($\simeq 10$ kpc) [C II] halos around high-redshift ($z \gtrsim 5$) star-forming galaxies. If such extended structures are common, they may have an impact on the line intensity mapping (LIM) signal. We compute the LIM power spectrum including both the central galaxy and the [C II] halo, and study the detectability of such signal in an ALMA LIM survey. We model the central galaxy and the [C II] halo brightness with a S\’ersic+exponential profile. The model has two free parameters: the effective radius ratio $f_{R_e}$, and the central surface brightness ratio, $f_{\Sigma}$, between the two components. [C II] halos can significantly boost the LIM power spectrum signal. For example, for relatively compact [C II] halos ($f_\Sigma=0.4$, $f_{R_{\rm e}}=2.0$), the signal is boosted by $\simeq 20$ times; for more extended and diffuse halos ($f_\Sigma=0.1, f_{R_{\rm e}}=6.0$), the signal is boosted by $\simeq 100$ times. For the ALMA ASPECS survey (resolution $\theta_{\rm beam} = 1.13”$, survey area $\Omega_{\rm survey}=2.9\,\rm arcmin^{2}$), the [C II] power spectrum is detectable only if the deL14d [C II] – SFR relation holds. However, with an optimized survey ($\theta_{\rm beam} = 0.232”$, $\Omega_{\rm survey}=2.0\,\rm deg^{2}$), the power spectrum is detectable for almost all the [C II] – SFR relations considered in this paper. Such a survey can constrain $f_\Sigma$ ($f_{R_{\rm e}}$) with a relative uncertainty of $60\%$ ($20\%$). A successful LIM experiment will provide unique constraints on the nature, origin, and frequency of extended [C II] halos, and the [C II] – SFR relation at early times.

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M. Zhang, A. Ferrara and B. Yue
Mon, 17 Apr 23
12/51

Comments: 12 pages, 8 figures

The Kinematics, Metallicities, and Orbits of Six Recently Discovered Galactic Star Clusters with Magellan/M2FS Spectroscopy [GA]

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http://arxiv.org/abs/2304.06904


We present Magellan/M2FS spectroscopy of four recently discovered Milky Way star clusters (Gran 3, Gran 4, Garro 01, LP 866) and two newly discovered open clusters (Gaia 9, Gaia 10) at low Galactic latitudes. We measure line-of-sight velocities and stellar parameters ([Fe/H], $\log{g}$, $T_{\rm eff}$, [Mg/Fe]) from high resolution spectroscopy centered on the Mg triplet and identify 20-80 members per star cluster. We determine the kinematics and chemical properties of each cluster and measure the systemic proper motion and orbital properties by utilizing Gaia astrometry. We find Gran 3 to be an old, metal-poor (mean metallicity of [Fe/H]=-1.84) globular cluster located in the Galactic bulge on a retrograde orbit. Gran 4 is an old, metal-poor ([Fe/H]}=-1.84) globular cluster with a halo-like orbit that happens to be passing through the Galactic plane. The orbital properties of Gran 4 are consistent with the proposed LMS-1/Wukong and/or Helmi streams merger events. Garro 01 is an old, metal-rich ([Fe/H]=-0.30) globular cluster on a near circular orbit in the outer disk. Gaia 9 and Gaia 10 are among the most distant known open clusters at $R_{GC}\sim 18, 21.2~kpc$ and most metal-poor with [Fe/H]~-0.50,-0.46 for Gaia 9 and Gaia 10, respectively. LP 866 is a nearby, metal-rich open cluster ([Fe/H]$=+0.1$). The discovery and confirmation of multiple star clusters in the Galactic plane shows the power of {\it Gaia} astrometry and the star cluster census remains incomplete.

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A. Pace, S. Koposov, M. Walker, et. al.
Mon, 17 Apr 23
13/51

Comments: 19 pages, 15 figures, submitted to MNRAS, associated data products available at this https URL

THESAN-HR: Galaxies in the Epoch of Reionization in warm dark matter, fuzzy dark matter and interacting dark matter [GA]

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http://arxiv.org/abs/2304.06742


Using high-resolution cosmological radiation-hydrodynamic (RHD) simulations (THESAN-HR), we explore the impact of alternative dark matter (altDM) models on galaxies during the Epoch of Reionization. The simulations adopt the IllustrisTNG galaxy formation model. We focus on altDM models that exhibit small-scale suppression of the matter power spectrum, namely warm dark matter (WDM), fuzzy dark matter (FDM), and interacting dark matter (IDM) with strong dark acoustic oscillations (sDAO). In altDM scenarios, both the halo mass functions and the UV luminosity functions at $z\gtrsim 6$ are suppressed at the low-mass/faint end, leading to delayed global star formation and reionization histories. However, strong non-linear effects enable altDM models to “catch up” with cold dark matter (CDM) in terms of star formation and reionization. The specific star formation rates are enhanced in halos below the half-power mass in altDM models. This enhancement coincides with increased gas abundance, reduced gas depletion times, more compact galaxy sizes, and steeper metallicity gradients at the outskirts of the galaxies. These changes in galaxy properties can help disentangle altDM signatures from a range of astrophysical uncertainties. Meanwhile, it is the first time that altDM models have been studied in RHD simulations of galaxy formation. We uncover significant systematic uncertainties in reionization assumptions on the faint-end luminosity function. This underscores the necessity of accurately modeling the small-scale morphology of reionization in making predictions for the low-mass galaxy population. Upcoming James Webb Space Telescope (JWST) imaging surveys of deep, lensed fields hold potential for uncovering the faint, low-mass galaxy population, which could provide constraints on altDM models.

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X. Shen, J. Borrow, M. Vogelsberger, et. al.
Mon, 17 Apr 23
14/51

Comments: To be submitted to MNRAS 22 pages, 12 Figures

The linear response of stellar systems does not diverge at marginal stability [GA]

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http://arxiv.org/abs/2304.07275


The linear response of a stellar system’s gravitational potential to a perturbing mass comprises two distinct contributions. Most famously, the system will respond by forming a polarization wake' around the perturber. At the same time, the perturber may also excite one or morenormal modes’, i.e. coherent oscillations of the entire stellar system which are either stable or unstable depending on the system parameters. The amplitude of the first (wake) contribution is known to diverge as a system approaches marginal stability. In this paper we consider the linear response of a homogeneous stellar system to a point mass moving on a straight line orbit. We prove analytically that the divergence of the wake response is in fact cancelled by a corresponding divergence in the normal mode response, rendering the total response finite. We demonstrate this cancellation explicitly for a box of stars with Maxwellian velocity distribution. Our results imply that polarization wakes may be much less efficient drivers of secular evolution than previously thought. More generally, any prior calculation that accounted for wakes but ignored modes may need to be revised.

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C. Hamilton and T. Heinemann
Mon, 17 Apr 23
15/51

Comments: 5 pages, 2 figures

Revisiting the trajectory of the interstellar object 'Oumuamua: preference for a radially directed non-gravitational acceleration? [EPA]

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http://arxiv.org/abs/2304.06964


I present a re-analysis of the available observational constraints on the trajectory of ‘Oumuamua, the first confirmed interstellar object discovered in the solar system. ‘Oumuamua passed through the inner solar system on a hyperbolic (i.e., unbound) trajectory. Its discovery occurred after perihelion passage, and near the time of its closest approach to Earth. After being observable for approximately four months, the object became too faint and was lost at a heliocentric distance of around 3 au. Intriguingly, analysis of the trajectory of ‘Oumuamua revealed that a dynamical model including only gravitational accelerations does not provide a satisfactory fit of the data, and a non-gravitational term must be included. The detected non-gravitational acceleration is compatible with either solar radiation pressure or recoil due to outgassing. It has, however, proved challenging to reconcile either interpretation with the existing quantitative models of such effects without postulating unusual physical properties for ‘Oumuamua (such as extremely low density and/or unusual geometry, non-standard chemistry). My analysis independently confirms the detection of the non-gravitational acceleration. After comparing several possible parametrizations for this effects, I find a strong preference for a radially directed non-gravitational acceleration, pointing away from the Sun, and a moderate preference for a power-law scaling with the heliocentric distance, with an exponent between 1 and 2. These results provide valuable constraints on the physical mechanism behind the effect; a conclusive identification, however, is probably not possible on the basis of dynamical arguments alone.

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F. Spada
Mon, 17 Apr 23
16/51

Comments: MATLAB code will be shared upon reasonable request to the author. Comments are welcome!

Exploring the Non-Gaussianity of the Cosmic Infrared Background and Its Weak Gravitational Lensing [CEA]

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http://arxiv.org/abs/2304.07283


Gravitational lensing deflects the paths of photons, altering the statistics of cosmic backgrounds and distorting their information content. We take the Cosmic Infrared Background (CIB), which provides a wealth of information about galaxy formation and evolution, as an example to probe the effect of gravitational lensing on non-Gaussian statistics. Using the Websky simulations, we first quantify the non-Gaussianity of the CIB, revealing additional detail on top of its well-measured power spectrum. To achieve this, we use needlet-like multipole-band-filters to calculate the variance and higher-point correlations. We show the 3-point and 4-point spectra, and compare our calculated bispectra to Planck values. We then lens the CIB, shell-by-shell with corresponding convergence maps, to capture the broad redshift extent of both the CIB and its lensing convergence. Using our simulations, we show that the lensed CIB power spectrum and bispectrum agree with observations: the lensing of the CIB changes the 3-point and 4-point functions by a few tens of percent at large scales, unlike with the power spectrum, which changes by less than two percent. We expand our analyses to encompass the full intensity probability distribution functions (PDFs) involving all n-point correlations as a function of scale. In particular we use the relative entropy between lensed and unlensed PDFs to create a spectrum of templates that can allow estimation of lensing. The underlying CIB model has uncertainties, in particular missing the important role of star-bursting, which has a larger effect on higher point correlations than on the variance. We test this by adding a stochastic log-normal term to the intensity distributions. The novel aspects of our filtering and lensing pipeline should prove useful for not just CIB applications, but for any radiant background, including line intensity maps.

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J. Lee, J. Bond, P. Motloch, et. al.
Mon, 17 Apr 23
17/51

Comments: 16 pages, 18 figures

Near-Core Acoustic Glitches are Not Oscillatory: Consequences for Asteroseismic Probes of Convective Boundary Mixing [SSA]

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http://arxiv.org/abs/2304.06770


Asteroseismology has been used extensively in recent years to study the interior structure and physical processes of main sequence stars. We consider prospects for using pressure modes (p-modes) near the frequency of maximum oscillation power to probe the structure of the near-core layers of main sequence stars with convective cores by constructing stellar model tracks. Within our mass range of interest, the inner turning point of p modes as determined by the JWKB approximation evolves in two distinct phases during the main sequence, implying a sudden loss of near-core sensitivity during the discontinuous transition between the two phases. However, we also employ non-JWKB asymptotic analysis to derive a contrasting set of expressions for the effects that these structural properties will have on the mode frequencies, which do not encode any such transition. We show analytically that a sufficiently near-core perturbation to the stellar structure results in non-oscillatory, degree-dependent perturbations to the star’s oscillation mode frequencies, contrasting with the case of an outer glitch. We also demonstrate numerically that these near-core acoustic glitches exhibit strong angular degree dependence, even at low degree, agreeing with the non-JWKB analysis, rather than the degree-independent oscillations which emerge from JWKB analyses. These properties have important implications for using p-modes to study near-core mixing processes for intermediate-mass stars on the main sequence, as well as for the interpretation of near-center acoustic glitches in other astrophysical configurations, such as red giants.

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C. Lindsay, J. Ong and S. Basu
Mon, 17 Apr 23
18/51

Comments: 14 pages, 5 figures, Accepted for publication in ApJ: April 12, 2023

Lossy Compression of Large-Scale Radio Interferometric Data [IMA]

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http://arxiv.org/abs/2304.07050


This work proposes to reduce visibility data volume using a baseline-dependent lossy compression technique that preserves smearing at the edges of the field-of-view. We exploit the relation of the rank of a matrix and the fact that a low-rank approximation can describe the raw visibility data as a sum of basic components where each basic component corresponds to a specific Fourier component of the sky distribution. As such, the entire visibility data is represented as a collection of data matrices from baselines, instead of a single tensor. The proposed methods are formulated as follows: provided a large dataset of the entire visibility data; the first algorithm, named $simple~SVD$ projects the data into a regular sampling space of rank$-r$ data matrices. In this space, the data for all the baselines has the same rank, which makes the compression factor equal across all baselines. The second algorithm, named $BDSVD$ projects the data into an irregular sampling space of rank$-r_{pq}$ data matrices. The subscript $pq$ indicates that the rank of the data matrix varies across baselines $pq$, which makes the compression factor baseline-dependent. MeerKAT and the European Very Long Baseline Interferometry Network are used as reference telescopes to evaluate and compare the performance of the proposed methods against traditional methods, such as traditional averaging and baseline-dependent averaging (BDA). For the same spatial resolution threshold, both $simple~SVD$ and $BDSVD$ show effective compression by two-orders of magnitude higher than traditional averaging and BDA. At the same space-saving rate, there is no decrease in spatial resolution and there is a reduction in the noise variance in the data which improves the S/N to over $1.5$ dB at the edges of the field-of-view.

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M. Atemkeng, S. Perkins, E. Seck, et. al.
Mon, 17 Apr 23
19/51

Comments: N/A

X-ray polarization evidence for a 200 years-old flare of Sgr A$^*$ [HEAP]

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http://arxiv.org/abs/2304.06967


The center of the Milky Way Galaxy hosts a $\sim$4 million solar mass black hole (Sgr A$^$) that is currently very quiescent with a luminosity many orders of magnitude below those of active galactic nuclei. Reflection of X-rays from Sgr A$^$ by dense gas in the Galactic Center region offers a means to study its past flaring activity on times scales of hundreds and thousands of years. The shape of the X-ray continuum and the strong fluorescent iron line observed from giant molecular clouds in the vicinity of Sgr A$^$ are consistent with the reflection scenario. If this interpretation is correct, the reflected continuum emission should be polarized. Here we report observations of polarized X-ray emission in the direction of the Galactic center molecular clouds using the Imaging X-ray Polarimetry Explorer (IXPE). We measure a polarization degree of 31\% $\pm$ 11\%, and a polarization angle of $-$48$^\circ$ $\pm$ 11$^\circ$. The polarization angle is consistent with Sgr A$^$ being the primary source of the emission, while the polarization degree implies that some 200 years ago the X-ray luminosity of Sgr A$^*$ was briefly comparable to a Seyfert galaxy.

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F. Marin, E. Churazov, I. Khabibullin, et. al.
Mon, 17 Apr 23
20/51

Comments: 24 pages, 5 figures, 4 tables, author’s version of the paper accepted for publication in Nature

Effective Field Theories for Dark Matter Pairs in the Early Universe [CL]

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http://arxiv.org/abs/2304.07180


In this conference paper, we consider effective field theories of non-relativistic dark matter particles interacting with a light force mediator in the early expanding universe. We present a general framework, where to account in a systematic way for the relevant processes that may affect the dynamics during thermal freeze-out. In the temperature regime where near-threshold effects, most notably the formation of bound states and Sommerfeld enhancement, have a large impact on the dark matter relic density, we scrutinize possible contributions from higher excited states and radiative corrections in the annihilations and decays of dark-matter pairs.

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S. Biondini, N. Brambilla, G. Qerimi, et. al.
Mon, 17 Apr 23
21/51

Comments: Discussion about hierarchies of scales improved with respect to the published version in the conference proceedings. 4 pages, 2 figures, conference proceeding of “NuDM-2022”

Solar P-angle Alignment in GONG Dopplergrams [SSA]

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http://arxiv.org/abs/2304.07192


In helioseismic studies, an observational parameter of primary concern is the P-angle, the angle along which lies the solar axis of rotation for a given image. For the six observing sites employed by The Global Oscillation Network Group (GONG), this angle acts additionally as a marker of relative image orientation, allowing concurrent images to be precisely aligned and merged to provide the highest possible quality data. In this report, we present and investigate two methods of determining the P-angle via the rotational signature embedded in solar Dopplergram images by examining the large-scale structure of the observed velocity field. As with other studies, we find that the Dopplergram produces a time-varying ‘P-angle’ signature according to the presentation of various physical phenomena across the solar surface, but with the potential for sub-degree identification of the axis of rotation. However, close agreement between separate P-angle-finding techniques also reveals current limitations to P-angle determination that are imposed by the calibration state of the GONG-site Dopplergrams, leaving these P-angle-finding methods for GONG with errors on the scale of less than a degree between two site.

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A. Hughes, I. Gonzalez-Hernandez, S. McManus, et. al.
Mon, 17 Apr 23
22/51

Comments: 36 pages, 32 figures

A benchmark study of atomic models for the transition region against quiet Sun observations [SSA]

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http://arxiv.org/abs/2304.07038


The use of the coronal approximation to model line emission from the solar transition region has led to discrepancies with observations over many years, particularly for Li- and Na-like ions. Studies have shown that a number of atomic processes are required to improve the modelling for this region, including the effects of high densities, solar radiation and charge transfer on ion formation. Other non-equilibrium processes, such as time dependent ionisation and radiative transfer, are also expected to play a role. A set of models which include the three relevant atomic processes listed above in ionisation equilibrium has recently been built. These new results cover the main elements observed in the transition region. To assess the effectiveness of the results, the present work predicts spectral line intensities using differential emission measure modelling. Although limited in some respects, this differential emission measure modelling does give a good indication of the impact of the new atomic calculations. The results are compared to predictions of the coronal approximation and to observations of the average, quiet Sun from published literature. Significant improvements are seen for the line emission from Li- and Na-like ions, inter-combination lines and many other lines. From this study, an assessment is made of how far down into the solar atmosphere the coronal approximation can be applied, and the range over which the new atomic models are valid.

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R. Dufresne, G. Zanna and H. Mason
Mon, 17 Apr 23
23/51

Comments: Accepted by MNRAS, 16 pages, 3 figures

The Strength of the Sheared Magnetic Field in the Galactic's Circum-Nuclear Disk [GA]

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http://arxiv.org/abs/2304.06823


Recent high-resolution 53-$\mu$m polarimetric observations from SOFIA/HAWC+ revealed the inferred plane-of-the-sky magnetic field (B-field) orientation in the Galactic center’s Circum-Nuclear Disk (CND). The B-field is mostly aligned with the steamers of ionized material falling onto Sgr A* at large, differential velocities (shear). In such conditions, estimating the B-field strength with the classical" Davis-Chandrasekhar-Fermi (DCF) method does not provide accurate results. We derive amodified” DCF method by solving the ideal MHD equations from first principles considering the effects of a large-scale, shear flow on the propagation of a fast magnetosonic wave. In the context of the DCF approximation, both the value of the shear and its Laplacian affect the inferred B-field strength. Using synthetic polarization data from MHD simulations for a medium dominated by shear flows, we find that the classical'' DCF determines B-field strengths only within $&gt;50$\% of the true value where themodified” DCF results are improved significantly ($\sim$3-22\%). Applying our “modified” DCF method to the CND revealed B-field strengths of $\sim1 – 16$ mG in the northern arm, $\sim1 – 13$ mG in the eastern arm, and $\sim3 – 27$ mG in the western arm at spatial scales $\lesssim1$ pc. The balance between turbulent gas energy (kinetic + hydrostatic) and turbulent magnetic energy densities suggest that, along the magnetic-field-flow direction, magnetic effects become less dominant as the shear flow increases and weakens the B-field via magnetic convection. Our results indicate that the transition from magnetically to gravitationally dominated accretion of material onto Sgr A* starts at distances $\sim$ 1 pc.

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J. Guerra, E. Lopez-Rodriguez, D. Chuss, et. al.
Mon, 17 Apr 23
24/51

Comments: Submitted to ApJ; Under review

Optical characteristics and capabilities of the successive versions of Meudon and Haute Provence H$α$ heliographs (1954-2004) [IMA]

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http://arxiv.org/abs/2304.07055


H$\alpha$ heliographs are imaging instruments designed to produce monochromatic images of the solar chromosphere at fast cadence (60 s or less). They are designed to monitor efficiently dynamic phenomena of solar activity, such as flares or material ejections. Meudon and Haute Provence observatories started systematic observations in the frame of the International Geophysical Year (1957) with Lyot filters. This technology evolved several times until 1985 with tunable filters allowing to observe alternatively the line wings and core (variable wavelength). More than 6 million images were produced during 50 years, mostly on 35 mm films (catalogs are available on-line). We present in this paper the optical characteristics and the capabilities of the successive versions of the H$\alpha$ heliographs in operation between 1954 and 2004, and describe briefly the new heliograph (MeteoSpace) which will be commissioned in 2023 at Calern observatory.

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J. Malherbe
Mon, 17 Apr 23
25/51

Comments: N/A

Galaxy clusters in the Vela supercluster. — I. Deep NIR catalogues [GA]

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http://arxiv.org/abs/2304.07208


We present six deep Near-InfraRed (JHK_s) photometric catalogues of galaxies identified in six cluster candidates (VC02, VC04, VC05, VC08, VC10, VC11) within the Vela Supercluster (VSCL) as part of our efforts to learn more about this large supercluster which extends across the zone of avoidance (l=272.5 \pm 20 deg, b= \pm 10 deg, at cz~ 18000 km/s). The observations were conducted with the InfraRed Survey Facility (IRSF), a 1.4m telescope situated at the South African Astronomical Observatory (SAAO) in Sutherland. The images in each cluster cover ~ 80% of their respective Abell radii. We identified a total number of 1715 galaxies distributed over the six cluster candidates, of which only ~ 15% were previously known. We study the structures and richnesses of the six clusters out to the cluster-centric completeness radius of r_c<1.5 Mpc and magnitude completeness limit of K_s^0<15.5 mag, using their iso-density contour maps and radial density profiles. The analysis shows VC04 to be the richest of the six. It is a massive cluster comparable to the Coma and Norma clusters, although its velocity dispersion, sigma=455 km/s, seems rather low for a rich cluster. VC02 and VC05 are found to be relatively rich clusters while VC08 is rather poor. Also, VC05 has the highest central number density among the six. VC11 is an intermediate cluster that contains two major subclusters while VC10 has a filament-like structure and is likely not to be a cluster after all.

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N. Hatamkhani, R. Kraan-Korteweg, S. Blyth, et. al.
Mon, 17 Apr 23
26/51

Comments: 18 pages, 10 Figures, 13 Tables. Accepted for publication in MNRAS

Late-formed halos prefer to host quiescent central galaxies. I. Observational results [GA]

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http://arxiv.org/abs/2304.07189


The star formation and quenching of central galaxies are regulated by the assembly histories of their host halos. In this work, we use the central stellar mass to halo mass ratio as a proxy of halo formation time, and we devise three different models, from the physical hydrodynamical simulation to the empirical statistical model, to demonstrate its robustness. With this proxy, we inferred the dependence of the central galaxy properties on the formation time of their host halos using the SDSS main galaxy sample, where central galaxies are identified with the halo-based group finder. We found that central galaxies living in late-formed halos have higher quiescent fractions and lower spiral fractions than their early-formed counterparts by $\lesssim$ 8%. Finally, we demonstrate that the group finding algorithm has a negligible impact on our results.

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K. Wang, Y. Chen, Q. Li, et. al.
Mon, 17 Apr 23
27/51

Comments: 14 pages, 7 + 5 figures, MNRAS accepted

The Impacts of Neutron-Star Structure and Base Heating on Type I X-Ray Bursts and Code Comparison [HEAP]

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http://arxiv.org/abs/2304.07197


Type I X-ray bursts are rapidly brightening phenomena triggered by thermonuclear burning on accreting layer of a neutron star (NS). The light curves represent the physical properties of NSs and the nuclear reactions on the proton-rich nuclei. The numerical treatments of the accreting NS and physics of the NS interior are not established, which shows uncertainty in modelling for observed X-ray light curves. In this study, we investigate theoretical X-ray-burst models, compared with burst light curves with GS~1826-24 observations. We focus on the impacts of the NS mass, the NS radius, and base-heating on the NS surface using the MESA code. We find a monotonic correlation between the NS mass and the parameters of the light curve. The higher the mass, the longer the recurrence time and the greater the peak luminosity. While the larger the radius, the longer the recurrence time, the peak luminosity remains nearly constant. In the case of increasing base heating, both the recurrence time and peak luminosity decrease. We also examine the above results using with a different numerical code, HERES, based on general relativity and consider the central NS. We find that the burst rate, burst energy and burst strength are almost same in two X-ray burst codes by adjusting the base-heat parameter in MESA (the relative errors $\lesssim5\%$), while the duration time and the rise time are significantly different between (the relative error is possibly $\sim50\%$). The peak luminosity and the e-folding time are ragged between two codes for different accretion rates.

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G. Zhen, G. Lv, H. Liu, et. al.
Mon, 17 Apr 23
28/51

Comments: 14 pages, 10 figures, accepted for publication in ApJ

$\texttt{LIMpy}$: A Semi-analytic Approach to Simulating Multi-line Intensity Maps at Millimetre Wavelengths [GA]

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http://arxiv.org/abs/2304.06748


Mapping of multiple lines such as the fine-structure emission from [CII] (157.7 $\mu \text{m}$), [OIII] (52 \& 88.4 $\mu \text{m}$), and rotational emission lines from CO are of particular interest for upcoming line intensity mapping (LIM) experiments at millimetre wavelengths, due to their brightness features. Several upcoming experiments aim to cover a broad range of scientific goals, from detecting signatures of the epoch of reionization to the physics of star formation and its role in galaxy evolution. In this paper, we develop a semi-analytic approach to modelling line strengths as functions of the star formation rate (SFR) or infrared (IR) luminosity based on observations of local and high-z galaxies. This package, $\texttt{LIMpy}$ (Line Intensity Mapping in Python), estimates the intensity and power spectra of [CII], [OIII], and CO rotational transition lines up to the $J$-levels (1-0) to (13-12) based both on analytic formalism and on simulations. We develop a relation among halo mass, SFR, and multi-line intensities that permits us to construct a generic formula for the evolution of several line strengths up to $z \sim 10$. We implement a variety of star formation models and multi-line luminosity relations to estimate the astrophysical uncertainties on the intensity power spectrum of these lines. As a demonstration, we predict the signal-to-noise ratio of [CII] detection for an EoR-Spec-like instrument on the Fred Young Submillimeter Telescope (FYST). Furthermore, the ability to use any halo catalogue allows the $\texttt{LIMpy}$ code to be easily integrated into existing simulation pipelines, providing a flexible tool to study intensity mapping in the context of complex galaxy formation physics.

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A. Roy, D. Valentín-Martínez, K. Wang, et. al.
Mon, 17 Apr 23
29/51

Comments: 19 pages, 10 figures, comments are welcome

Results from the ARIANNA high-energy neutrino detector [IMA]

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http://arxiv.org/abs/2304.07179


The ARIANNA in-ice radio detector explores the detection of UHE neutrinos with shallow detector stations on the Ross Ice Shelf and the South Pole. Here, we present recent results that lay the foundation for future large-scale experiments. We show a limit on the UHE neutrino flux derived from ARIANNA data, measurements of the more abundant air showers, results from in-situ measurement campaigns, a study of a potential background from internal reflection layers, and give an outlook of future detector improvements.

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C. Glaser
Mon, 17 Apr 23
30/51

Comments: Proceedings of the 9th ARENA workshop 2022

What Does the Virial Coefficient of the \Hb Broad-Line Region Depend On? [GA]

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http://arxiv.org/abs/2304.06764


We combine our dynamical modeling black hole mass measurements from the Lick AGN Monitoring Project 2016 sample with measured cross-correlation time lags and line widths to recover individual scale factors, f, used in traditional reverberation mapping analyses. We extend our sample by including prior results from Code for AGN Reverberation and Modeling of Emission Lines (caramel) studies that have utilized our methods. Aiming to improve the precision of black hole mass estimates, as well as uncover any regularities in the behavior of the broad-line region (BLR), we search for correlations between f and other AGN/BLR parameters. We find (i) evidence for a correlation between the virial coefficient log10(fmean,{\sigma}) and black hole mass, (ii) marginal evidence for a similar correlation between log10(frms,{\sigma}) and black hole mass, (iii) marginal evidence for an anti-correlation of BLR disk thickness with log10(fmean,FWHM)and log10(frms,FWHM), and (iv) marginal evidence for an anti-correlation of inclination angle with log10(fmean,FWHM), log10(frms,{\sigma}), and log10(fmean,{\sigma}). Lastly, we find marginal evidence for a correlation between line-profile shape, when using the root-meansquare spectrum, log10(FWHM/{\sigma})rms, and the virial coefficient, log10(frms,{\sigma}), and investigate how BLR properties might be related to line-profile shape using caramel models.

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L. Villafaña, P. Williams, T. Treu, et. al.
Mon, 17 Apr 23
31/51

Comments: 17 pages, 10 figures

Optimizing the Resolution of Hydrodynamic Simulations for MCRaT Radiative Transfer Calculations [HEAP]

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http://arxiv.org/abs/2304.07287


Despite their discovery about half a century ago, the Gamma-ray burst (GRB) prompt emission mechanism is still not well understood. Theoretical modeling of the prompt emission has advanced considerably due to new computational tools and techniques. One such tool is the PLUTO hydrodynamics code, which is used to numerically simulate GRB outflows. PLUTO uses Adaptive Mesh Refinement to focus computational efforts on the portion of the grid that contains the simulated jet. Another tool is the Monte Carlo Radiation Transfer (MCRaT) code, which predicts electromagnetic signatures of GRBs by conducting photon scatterings within a jet using PLUTO. The effects of the underlying resolution of a PLUTO simulation with respect to MCRaT post-processing radiative transfer results have not yet been quantified. We analyze an analytic spherical outflow and a hydrodynamically simulated GRB jet with MCRaT at varying spatial and temporal resolutions and quantify how decreasing both resolutions affect the resulting mock observations. We find that changing the spatial resolution changes the hydrodynamic properties of the jet, which directly affect the MCRaT mock observable peak energies. We also find that decreasing the temporal resolution artificially decreases the high energy slope of the mock observed spectrum, which increases both the spectral peak energy and the luminosity. We show that the effects are additive when both spatial and temporal resolutions are modified. Our results allow us to understand how decreased hydrodynamic temporal and spatial resolutions affect the results of post-processing radiative transfer calculations, allowing for the optimization of hydrodynamic simulations for radiative transfer codes.

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J. Arita-Escalante, T. Parsotan and S. Cenko
Mon, 17 Apr 23
32/51

Comments: 12 pages, 10 figures, submitted to ApJ, for calculations, see: this https URL

Parity violating scalar-tensor model in teleparallel gravity and its cosmological application [CL]

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http://arxiv.org/abs/2304.07138


The parity violating model based on teleparallel gravity is a competitive scheme for parity violating gravity, which has been preliminary studied in the literature. To further investigate the parity violating model in teleparallel gravity, in this paper, we construct all independent parity-odd terms that are quadratic in torsion tensor and coupled to a scalar field in a way without higher-order derivatives. Using these parity-odd terms, we formulate a general parity violating scalar-tensor model in teleparallel gravity and obtain its equations of motion. To explore potentially viable models within the general model, we investigate the cosmological application of a submodel of the general model in which terms above the second power of torsion are eliminated. We focus on analyzing cosmological perturbations and identify the conditions that preserve the parity violating signal of gravitational waves at linear order while avoiding the ghost instability.

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H. Rao and D. Zhao
Mon, 17 Apr 23
33/51

Comments: 17 pages. arXiv admin note: text overlap with arXiv:2201.02357, arXiv:2301.02847

A brief History of Image Sensors in the Optical [IMA]

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http://arxiv.org/abs/2304.07121


Image sensors, most notably the Charge Coupled Device (CCD), have revolutionized observational astronomy as perhaps the most important innovation after photography. Since the 50th anniversary of the invention of the CCD has passed in 2019, it is time to review the development of detectors for the visible wavelength range, starting with the discovery of the photoelectric effect and first experiments to utilize it for the photometry of stars at Sternwarte Babelsberg in 1913, over the invention of the CCD, its development at the Jet Propulsion Laboratory, to the high performance CCD and CMOS imagers that are available off-the-shelf today.

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M. Roth
Mon, 17 Apr 23
34/51

Comments: 9 pages, 10 figures. Presented at SDW2022, accepted for publication in Special Issue of Astronomische Nachrichten

Iron-Peak Element Abundances in Warm Very Metal-Poor Stars [SSA]

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http://arxiv.org/abs/2304.06899


We have derived new detailed abundances of Mg, Ca, and the Fe-group elements Sc through Zn (Z = 21-30) for 37 main sequence turnoff very metal-poor stars ([Fe/H] <= -2.1). We analyzed Keck HIRES optical and near-UV high signal-to-noise spectra originally gathered for a beryllium abundance survey. Using typically about 400 Fe-group lines with accurate laboratory transition probabilities for each star, we have determined accurate LTE metallicities and abundance ratios for neutral and ionized species of the 10 Fe-group elements as well as alpha elements Mg and Ca. We find good neutral/ion abundance agreement for the 6 elements that have detectable transitions of both species in our stars in the 3100-5800 Angstrom range. Earlier reports of correlated Sc-Ti-V relative overabundances are confirmed, and appear to slowly increase with decreasing metallicity. To this element trio we add Zn; it also appears to be increasingly overabundant in the lowest metallicity regimes. Co appears to mimic the behavior of Zn, but issues surrounding its abundance reliability cloud its interpretation.

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C. Sneden, A. Boesgaard, J. Cowan, et. al.
Mon, 17 Apr 23
35/51

Comments: ApJ, in press

The ultradense, interacting environment of a dual AGN at z $\sim$ 3.3 revealed by JWST/NIRSpec IFS [GA]

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http://arxiv.org/abs/2304.06756


LBQS 0302-0019 is a blue quasar (QSO) at z $\sim$ 3.3, hosting powerful outflows, and residing in a complex environment consisting of an obscured AGN candidate, and multiple companions, all within 30 kpc in projection. We use JWST NIRSpec IFS observations to characterise the ionized gas in this complex system. We develop a procedure to correct for the spurious oscillations (or ‘wiggles’) in NIRSpec single-spaxel spectra, due to the spatial under-sampling of the point spread function. We perform a quasar-host decomposition with the QDeblend3D tools, and use multi-component kinematic decomposition of the optical emission line profiles to infer the physical properties of the emitting gas. The quasar-host decomposition allows us to identify i) a low-velocity component possibly tracing a warm rotating disk, with a dynamical mass Mdyn $\sim 10^{11}$ Msun and a rotation-to-random motion ratio $v_{rot}$/$\sigma_0 \sim 2$; ii) a spatially unresolved ionised outflow, with a velocity of $\sim$ 1000 km/s and an outflow mass rate of $\sim 10^4$ Msun/yr. We also detect eight interacting companion objects close to LBQS 0302-0019. Optical line ratios confirm the presence of a second, obscured AGN at $\sim 20$ kpc of the primary QSO; the dual AGN dominates the ionization state of the gas in the entire NIRSpec field-of-view. This work has unveiled with unprecedented detail the complex environment of this dual AGN, which includes nine interacting companions (five of which were previously unknown), all within 30 kpc of the QSO. Our results support a scenario where mergers can trigger dual AGN, and can be important drivers for rapid early SMBH growth.

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M. Perna, S. Arribas, M. Marshall, et. al.
Mon, 17 Apr 23
36/51

Comments: 23 pages, 23 figures; Submitted to A&A; Comments welcome!

Observational constraints on the metagalactic Ly$α$ photon scattering rate at high redshift [CEA]

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http://arxiv.org/abs/2304.07085


The scattering of Ly$\alpha$ photons from the first radiating sources in the Universe plays a pivotal role in 21-cm radio detections of Cosmic Dawn and the Epoch of Reionization through the Wouthuysen-Field effect. New data from JWST show the Ly$\alpha$ photon scattering rate exceeds that required to decouple the intergalactic hydrogen spin temperature from that of the Cosmic Microwave Background up to $z\sim14$ and render the neutral hydrogen visible over the main redshift range expected for the Epoch of Reionization.

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A. Meiksin
Mon, 17 Apr 23
37/51

Comments: Published in the Research Notes of the American Astronomical Society; 3 pages, 1 figure

Magnetic winding and turbulence in ultra-hot Jupiters [EPA]

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http://arxiv.org/abs/2304.07066


While magnetism in exoplanets remains largely unknown, Hot Jupiters have been considered as natural candidates to harbour intense magnetic fields, both due to their large masses and their high energy budgets coming from irradiation as a consequence of their vicinity to their host stars. In this work we perform MHD simulations of a narrow day-side atmospheric column of ultra-hot Jupiters, suitable for very high local temperatures (T > 3000 K). Since the conductivity in this regime is very high, the dominant effect is winding due to the intense zonal winds. By including a forcing that mimics the wind profiles obtained in global circulation models, the shear layer induces a strong toroidal magnetic field (locally reaching hundreds of gauss), supported by meridional currents. Such fields and the sustaining currents don$’$t depend on the internally generated field, but are all confined in the thin (less than a scale-height) shear layer around 1 bar. Additionally, we add random perturbations that induce turbulent motions, which lead to further (but much smaller) magnetic field generation to a broader range of depths. These results allow an evaluation of the currents induced by the atmospheric dynamo. Although here we use ideal MHD and the only resistivity comes from the numerical scheme, we estimate a-posteriori the amount of Ohmic heat deposited in the outer layers, which could be employed in evolutionary models for Hot Jupiters’ inflated radii.

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C. Soriano-Guerrero, D. Viganò, R. Perna, et. al.
Mon, 17 Apr 23
38/51

Comments: submitted for publication in MNRAS

The distance to the Serpens South Cluster from H2O masers [GA]

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http://arxiv.org/abs/2304.07270


In this Letter, we report Very Long Baseline Array observations of 22 GHz water masers toward the protostar CARMA-6, located at the center of the Serpens South young cluster. From the astrometric fits to maser spots, we derive a distance of 440.7+/-3.5 pc for the protostar (1% error). This represents the best direct distance determination obtained so far for an object this young and deeply embedded in this highly obscured region. Taking into account depth effects, we obtain a distance to the cluster of 440.7+/-4.6 pc. Stars visible in the optical that have astrometric solutions in the Gaia Data Release 3 are, on the other hand, all located in the periphery of the cluster. Their mean distance of 437 (+51, -41) pc is consistent within 1-sigma with the value derived from maser astrometry. As the maser source is just at the center of Serpens South, we finally solve the ambiguity of the distance to this region that has prevailed over the years.

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G. Ortiz-Leon, S. Dzib, L. Loinard, et. al.
Mon, 17 Apr 23
39/51

Comments: Accepted to A&A Letters

CAPP Axion Search Experiments with Quantum Noise Limited Amplifiers [CL]

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http://arxiv.org/abs/2304.07222


The axion is expected to solve the strong CP problem of quantum chromodynamics and is one of the leading candidates for dark matter. CAPP in South Korea has several axion search experiments based on cavity haloscopes in the frequency range of 1-6 GHz. The main effort focuses on operation of the experiments with the highest possible sensitivity. It requires maintenance of the haloscopes at the lowest physical temperature in the range of mK and usage of low noise components to amplify the weak axion signal. We report development and operation of low noise amplifiers for 5 haloscope experiments targeting at different frequency ranges. The amplifiers show noise temperatures approaching the quantum limit.

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S. Uchaikin, B. Ivanov, J. Kim, et. al.
Mon, 17 Apr 23
40/51

Comments: 6 pages, 7 figures, 29th International Conference on Low Temperature Physics, August 18-24, 2022, Sapporo, Japan

Neutrino signals from Neutron Star implosions to Black Holes [CEA]

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http://arxiv.org/abs/2304.06746


We calculate the neutrino luminosity in an astrophysical scenario where dark matter is captured by a neutron star which eventually implodes to form a low mass black hole. The Trojan horse scenario involves the collapse of a neutron star (NS) due to the accumulation of a critical amount of dark matter (DM) during its lifetime. As a result, a central disk forms out of the ejected material with a finite radial extension, density, temperature, and lepton fraction, producing fainter neutrino luminosities and colder associated spectra than found in a regular core-collapse supernova. The emitted gravitational wave (GW) signal from the imploding NS should be detectable at ultra-high $\gtrsim 0.1$ GHz frequencies.

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Y. Zenati, C. Albertus, M. Pérez-García, et. al.
Mon, 17 Apr 23
41/51

Comments: comments are welcome

UVIT view of NGC 5291: Ongoing star formation in tidal dwarf galaxies at ~ 0.35 kpc resolution [GA]

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http://arxiv.org/abs/2304.07244


NGC 5291, an early-type galaxy surrounded by a giant HI ring, is believed to be formed from collision with another galaxy. Several star forming complexes and tidal dwarf galaxies are distributed along the collisional ring which are sites of star formation in environments where extreme dynamical effects are involved. Dynamical effects can affect the star formation properties and the spatial distribution of star forming complexes along the tidal features. To study and quantify the star formation activity in the main body and in the ring structure of the NGC 5291 system, we use high spatial resolution FUV and NUV imaging observations from the Ultraviolet Imaging Telescope onboard AstroSat. A total of 57 star-forming knots are identified to be part of this interacting system out of which 12 are new detections (star forming complexes that lie inside the HI contour) compared to the previous measurements from lower resolution UV imaging. We estimate the attenuation in UV for each of the resolved star-forming knots using the UV spectral slope $\beta$, derived from the FUV-NUV colour. Using the extinction corrected UV fluxes, we derive the star formation rate of the resolved star forming complexes. The extinction corrected total star formation rate of this system is estimated as 1.75 $\pm$ 0.04 $M_{\odot}/yr$. The comparison with dwarf galaxy populations (BCD, Sm and dIm galaxies) in the nearby Universe shows that many of the knots in the NGC 5291 system have SFR values comparable to the SFR of BCD galaxies.

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R. R, G. Santhosh, P. Joseph, et. al.
Mon, 17 Apr 23
42/51

Comments: Accepted for publication in MNRAS. Appendix table can be found in published version

A catalogue of cataclysmic variables from 20 years of the Sloan Digital Sky Survey with new classifications, periods, trends and oddities [SSA]

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http://arxiv.org/abs/2304.06749


We present a catalogue of 507 cataclysmic variables (CVs) observed in SDSS I to IV including 70 new classifications collated from multiple archival data sets. This represents the largest sample of CVs with high-quality and homogeneous optical spectroscopy. We have used this sample to derive unbiased space densities and period distributions for the major sub-types of CVs. We also report on some peculiar CVs, period bouncers and also CVs exhibiting large changes in accretion rates. We report 70 new CVs, 59 new periods, 178 unpublished spectra and 262 new or updated classifications. From the SDSS spectroscopy, we also identified 18 systems incorrectly identified as CVs in the literature. We discuss the observed properties of 13 peculiar CVS, and we identify a small set of eight CVs that defy the standard classification scheme. We use this sample to investigate the distribution of different CV sub-types, and we estimate their individual space densities, as well as that of the entire CV population. The SDSS I to IV sample includes 14 period bounce CVs or candidates. We discuss the variability of CVs across the Hertzsprung-Russell diagram, highlighting selection biases of variability-based CV detection. Finally, we searched for, and found eight tertiary companions to the SDSS CVs. We anticipate that this catalogue and the extensive material included in the Supplementary Data will be useful for a range of observational population studies of CVs.

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K. Inight, B. Gänsicke, E. Breedt, et. al.
Mon, 17 Apr 23
43/51

Comments: Submitted to MNRAS. Supplementary information available at this https URL

Dissect two-halo galactic conformity effect for central galaxies: The dependence of star formation activities on the large-scale environment [GA]

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http://arxiv.org/abs/2304.06886


We investigate the two-halo galactic conformity effect for central galaxies, which is the spatial correlation of the star formation activities for central galaxies to several Mpcs, by studying the dependence of the star formation activities of central galaxies on their large-scale structure in our local Universe using the SDSS data. Here we adopt a novel environment metric using only central galaxies quantified by the distance to the $n$-th nearest central galaxy. This metric measures the environment within an aperture from $\sim$ 1 Mpc to $\gtrsim$ 10 Mpc, with a median value of $\sim$ 4 Mpc. We found that two kinds of conformity effects in our local Universe. The first one is that low-mass central galaxies are more quenched in high-density regions, and we found that this effect mainly comes from low-mass centrals that are close to a more massive halo. A similar trend is also found in the IllustrisTNG simulation, which can be entirely explained by backsplash galaxies. The second conformity effect is that massive central galaxies in low-density regions are more star-forming. This population of galaxies also possesses a higher fraction of spiral morphology and lower central stellar velocity dispersion, suggesting that their low quiescent fraction is due to less-frequent major merger events experienced in the low-density regions, and as a consequence, less-massive bulges and central black holes.

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K. Wang, Y. Peng and Y. Chen
Mon, 17 Apr 23
44/51

Comments: 13 pages, 9 figures, accepted by MNRAS

Photometric activity of CQ Tau on the time interval of 125 years [SSA]

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http://arxiv.org/abs/2304.07115


The star CQ Tau belongs to the family of UX Ori type stars. It has very complex photometric behavior and complex structure of the circumstellar environment. In our paper we constructed the historical 125 years light curve of this star basing on the published photometric observations. It follows that besides a random component characteristic of UX Ori type stars, the large amplitude periodic component with the 10 year period is also present. Its existence was suspected earlier in [11]. New observations confirm its reality. It points to an existence of the second component close to the star. The density waves and matter flows caused by the companion motion lead to periodic changes in the circumstellar extinction and brightness of the star. This result is discussed in context of the recent observations of CQ Tau with high angular resolution.

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V. Grinin, L. Tambovtseva, O. Barsunova, et. al.
Mon, 17 Apr 23
45/51

Comments: 7 pages, 4 figures, accepted by Astrophysics

Effects of Heat Conduction on Blocking off the Super-Eddington Growth of Black Holes at High Redshift [CEA]

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http://arxiv.org/abs/2304.07184


We investigate the effect of conductive heating of the gas surrounding a geometrically thick accretion disk on the growth of a black hole at high redshift. If a black hole is accreting the surrounding gas at a super-Eddington rate, the X-ray radiation from the vicinity of the black hole would be highly anisotropic due to the self-shielding of a geometrically thick accretion disk, and then the radiative feedback on the surrounding medium would be suppressed in the equatorial region, within which super-Eddington accretion can continue. However, if this region is sufficiently heated via thermal conduction from the adjacent region that is not shielded and heated by the X-ray irradiation, the surrounding gas becomes isotropically hot and the Bondi accretion rate would be suppressed and become sub-Eddington. We evaluate the condition under which such isotropic heating is realized, and derive new criteria required for super-Eddington accretion.

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N. Kawanaka and K. Kohri
Mon, 17 Apr 23
46/51

Comments: 11 pages, 6 figures

Lightning: An X-ray to Submillimeter Galaxy SED Fitting Code With Physically-Motivated Stellar, Dust, and AGN Models [GA]

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http://arxiv.org/abs/2304.06753


We present an updated version of Lightning, a galaxy spectral energy distribution (SED) fitting code that can model X-ray to submillimeter observations. The models in Lightning include the options to contain contributions from stellar populations, dust attenuation and emission, and active galactic nuclei (AGN). X-ray emission, when utilized, can be modeled as originating from stellar compact binary populations with the option to include emission from AGN. We have also included a variety of algorithms to fit the models to observations and sample parameter posteriors; these include an adaptive Markov-Chain Monte-Carlo (MCMC), affine-invariant MCMC, and Levenberg-Marquardt gradient decent (MPFIT) algorithms. To demonstrate some of the capabilities of Lightning, we present several examples using a variety of observational data. These examples include (1) deriving the spatially resolved stellar properties of the nearby galaxy M81, (2) demonstrating how X-ray emission can provide constrains on the properties of the supermassive black hole of a distant AGN, (3) exploring how to rectify the attenuation effects of inclination on the derived the star formation rate of the edge-on galaxy NGC 4631, (4) comparing the performance of Lightning to similar Bayesian SED fitting codes when deriving physical properties of the star-forming galaxy NGC 628, and (5) comparing the derived X-ray and UV-to-IR AGN properties from Lightning and CIGALE for a distant AGN. Lightning is an open-source application developed in the Interactive Data Language (IDL) and is available at https://github.com/rafaeleufrasio/lightning.

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K. Doore, E. Monson, R. Eufrasio, et. al.
Mon, 17 Apr 23
47/51

Comments: 34 pages, 17 figures. Accepted to ApJ

Performance of TES X-Ray Microcalorimeters Designed for 14.4-keV Solar Axion Search [IMA]

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http://arxiv.org/abs/2304.07068


A 57Fe nucleus in the solar core could emit a 14.4-keV monochromatic axion through the M1 transition if a hypothetical elementary particle, axion, exists to solve the strong CP problem. Transition edge sensor (TES) X-ray microcalorimeters can detect such axions very efficiently if they are again converted into photons by a 57Fe absorber. We have designed and produced a dedicated TES array with 57Fe absorbers for the solar axion search. The iron absorber is set next to the TES, keeping a certain distance to reduce the iron-magnetization effect on the spectroscopic performance. A gold thermal transfer strap connects them. A sample pixel irradiated from a 55Fe source detected 698 pulses. In contrast to thermal simulations, we consider that the pulses include either events produced in an iron absorber or gold strap at a fraction dependent on the absorption rate of each material. Furthermore, photons deposited on the iron absorber are detected through the strap as intended. The identification of all events still needs to be completed. However, we successfully operated the TES with the unique design under iron magnetization for the first time.

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Y. Yagi, R. Konno, T. Hayash, et. al.
Mon, 17 Apr 23
48/51

Comments: 10 pages, 6 figures, published in Journal of Low Temperature Physics on 4 February 2023

Effect of magnetic fields on the dynamics and gravitational wave emission of PPI-saturated self-gravitating accretion disks: simulations in full GR [HEAP]

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http://arxiv.org/abs/2304.07282


We explore the effect magnetic fields have on self-gravitating accretion disks around spinning black holes via numerical evolutions in full dynamical magnetohydrodynamic spacetimes. The configurations we study are unstable to the Papaloizou-Pringle Instability (PPI). PPI-saturated accretion tori have been shown to produce gravitational waves, detectable to cosmological distances by third-generation gravitational wave (GW) observatories. While the PPI operates strongly for purely hydrodynamic disks, the situation can be different for disks hosting initially small magnetic fields. Evolutions of disks without self-gravity in fixed BH spacetimes have shown that small seed fields can initiate the rapid growth of the magneto-rotational instability (MRI), which then strongly suppresses the PPI. Since realistic astrophysical disks are expected to be magnetized, PPI-generated GW signals may be suppressed as well. However, it is unclear what happens when the disk self-gravity is restored. Here, we study the impact of magnetic fields on the PPI-saturated state of a self-gravitating accretion disk around a spinning BH ($\chi = 0.7$) aligned with the disk angular momentum, as well as one around a non-spinning BH. We find the MRI is effective at reducing the amplitude of PPI modes and their associated GWs, but the systems still generate GWs. Estimating the detectability of these systems accross a wide range of masses, we show that magnetic fields reduce the maximum detection distance by Cosmic Explorer from 300Mpc (in the pure hydrodynamic case) to 45Mpc for a $10 M_{\odot}$ system, by LISA from 11500Mpc to 2700Mpc for a $2 \times 10^{5} M_{\odot}$ system, and by DECIGO from $z \approx 5$ down to $z \approx 2$ for a $1000 M_{\odot}$ system.

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E. Wessel, V. Paschalidis, A. Tsokaros, et. al.
Mon, 17 Apr 23
49/51

Comments: N/A

Measuring spin in coalescing binaries of neutron stars showing double precursors [HEAP]

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http://arxiv.org/abs/2304.07170


Gamma-ray bursts resulting from binary neutron-star mergers are sometimes preceded by precursor flares. These harbingers may be ignited by quasi-normal modes, excited by orbital resonances, shattering the stellar crust of one of the inspiralling stars up to $\gtrsim10$ seconds before coalescence. In the rare case that a system displays two precursors, successive overtones of either interface- or $g$-modes may be responsible for the overstrainings. Since the free-mode frequencies of these overtones have an almost constant ratio, and the inertial-frame frequencies for rotating stars are shifted relative to static ones, the spin frequency of the flaring component can be constrained as a function of the equation of state, the binary mass ratio, the mode quantum numbers, and the spin-orbit misalignment angle. As a demonstration of the method, we find that the precursors of GRB090510 hint at a spin frequency range of $2 \lesssim \nu_{\star}/\text{Hz} \lesssim 20$ for the shattering star if we allow for an arbitrary misalignment angle, assuming $\ell=2$ $g$-modes account for the events.

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H. Kuan, A. Suvorov and K. Kokkotas
Mon, 17 Apr 23
50/51

Comments: 11 pages, 6 figures, 2 tables, with an appendix containing 1 figure

Planet Eclipse Mapping with Long-Term Baseline Drifts [EPA]

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http://arxiv.org/abs/2304.06851


High precision lightcurves combined with eclipse mapping techniques can reveal the horizontal and vertical structure of a planet’s thermal emission and the dynamics of hot Jupiters. Someday, they even may reveal the surface maps of rocky planets. However, inverting lightcurves into maps requires an understanding of the planet, star and instrumental trends because they can resemble the gradual flux variations as the planet rotates (ie. partial phase curves). In this work, we simulate lightcurves with baseline trends and assess the impact on planet maps. Baseline trends can be erroneously modeled by incorrect astrophysical planet map features, but there are clues to avoid this pitfall in both the residuals of the lightcurve during eclipse and sharp features at the terminator of the planet. Models that use a Gaussian process or polynomial to account for a baseline trend successfully recover the input map even in the presence of systematics but with worse precision for the m=1 spherical harmonic terms. This is also confirmed with the ThERESA eigencurve method where fewer lightcurve terms can model the planet without correlations between the components. These conclusions help aid the decision on how to schedule observations to improve map precision. If the m=1 components are critical, such as measuring the East/West hotspot shift on a hot Jupiter, better characterization of baseline trends can improve the m=1 terms’ precision. For latitudinal North/South information from the remaining mapping terms, it is preferable to obtain high signal-to-noise at ingress/egress with more eclipses.

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E. Schlawin, R. Challener, M. Mansfield, et. al.
Mon, 17 Apr 23
51/51

Comments: AJ, accepted, 22 pages

HI 21 cm Extended Structures to the North-East, and South-West of NGC 5595: VLA Observations of the Disk Galaxy Pair NGC 5595 and NGC 5597 [GA]

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http://arxiv.org/abs/2304.06272


We report VLA B-configuration observations of the HI 21 cm line on the close disk galaxy pair NGC 5595 and NGC 5597. At the angular resolution of the observations, $\sim7.1” \times 4.2”$, while most of the HI 21 cm in NGC 5595 and in NGC 5597 has the same extent as the optical disk, we have detected for the first time extended structures (streamers) to the north-east (NE), and south-west (SW) of NGC 5595 with no counterparts in blue, red optical (continuum), 20 cm radio continuum, or H$\alpha$ spectral-line emission. One structure is extended by $\sim 45”$ to the NE with blue-shifted velocities, and the other by $\sim 20”$ to the SW with red-shifted velocities with respect to the systemic velocity. No HI 21 cm emission is detected from the innermost central (nuclear) regions of either galaxy. Lower angular resolution HI 21 cm imaging indicates the non-existence of any intergalactic HI 21 cm gas as tails or bridges between the two galaxies. Our new 20 cm radio continuum emission image of NGC 5597 shows a strong unresolved elongated structure at the central region, in the north-east south-west direction, very similar to the spatial location of the innermost H$\alpha$ spectral line emission. There is no 20 cm continuum emission from its north spiral arm. In NGC 5595, the 20 cm radio continuum image shows no continuum emission from the NE nor the SW extended structures with HI 21 cm emission.

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J. Garcia-Barreto and E. Momjian
Fri, 14 Apr 23
1/64

Comments: 22 pages, 14 figures. AJ accepted

AutoTAB: Automatic Tracking Algorithm for Bipolar Magnetic Regions [SSA]

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http://arxiv.org/abs/2304.06615


Bipolar Magnetic Regions (BMRs) provide crucial information about solar magnetism. They exhibit varying morphology and magnetic properties throughout their lifetime, and studying these properties can provide valuable insights into the workings of the solar dynamo. The majority of previous studies have counted every detected BMR as a new one and have not been able to study the full life history of each BMRs. To address this issue, we have developed an Automatic Tracking Algorithm (AutoTAB) for BMRs, that tracks the BMRs for their entire lifetime or throughout their disk passage. AutoTAB uses the binary maps of detected BMRs to automatically track the regions. This is done by differentially rotating the binary maps of the detected regions and checking for overlaps between them. In this first article of this project, we provide a detailed description of the working of the algorithm and evaluate its strengths and weaknesses. We also compare its performance with other existing tracking techniques. AutoTAB excels in tracking even for the small features and it successfully tracks 9152 BMRs over the last two solar cycles (1996-2020), providing a comprehensive dataset that depicts the evolution of various properties for each tracked region. The tracked BMRs follow familiar properties of solar cycles except for these small BMRs that appear at all phases of the solar cycle and show weak latitudinal dependency, which is represented through the butterfly diagram. Finally, we discuss the possibility of adapting our algorithm to other datasets and expanding the technique to track other solar features in the future.

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A. Sreedevi, B. Jha, B. Karak, et. al.
Fri, 14 Apr 23
2/64

Comments: 14 pages including 9 figures; Submitted in ApJS; Comments are welcome

Stochastic gravitational wave background from stellar origin binary black holes in LISA [CEA]

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http://arxiv.org/abs/2304.06368


We use the latest constraints on the population of stellar origin binary black holes (SOBBH) from LIGO/Virgo/KAGRA (LVK) observations, to estimate the stochastic gravitational wave background (SGWB) they generate in the frequency band of LISA. We account for the faint and distant binaries, which contribute the most to the SGWB, by extending the merger rate at high redshift assuming it tracks the star formation rate. We adopt different methods to compute the SGWB signal: an analytical evaluation, Monte Carlo sums over SOBBH population realisations, and a method that accounts for the role of the detector by simulating LISA data and iteratively removing resolvable signals until only the confusion noise is left, allowing for the extraction of both the expected SGWB and the number of resolvable SOBBHs. Since the latter are few for SNR thresholds larger than five, we confirm that the spectral shape of the SGWB in the LISA band follows the analytical prediction of a power law. We infer the probability distribution of the SGWB amplitude from the LVK GWTC-3 posterior of the binary population model; its interquartile range of $h^2\Omega_\mathrm{GW}(f=3\times10^{-3}\,\mathrm{Hz}) \in [5.65,\,11.5]\times10^{-13}$ is in agreement with most previous estimates. We perform a MC analysis to assess LISA’s capability to detect and characterise this signal. Accounting for both the instrumental noise and the galactic binaries foreground, with four years of data, LISA will be able to detect the SOBBH SGWB with percent accuracy, narrowing down the uncertainty on the amplitude by one order of magnitude with respect to the range of possible amplitudes inferred from the population model. A measurement of this signal by LISA will help to break the degeneracy among some of the population parameters, and provide interesting constraints, in particular on the redshift evolution of the SOBBH merger rate.

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S. Babak, C. Caprini, D. Figueroa, et. al.
Fri, 14 Apr 23
3/64

Comments: 39 pages, 15 figures

Interpolated kilonova spectra models: necessity for a phenomenological, blue component in the fitting of AT2017gfo spectra [HEAP]

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http://arxiv.org/abs/2304.06699


In this work, we present a simple interpolation methodology for spectroscopic time series, based on conventional interpolation techniques (random forests) implemented in widely-available libraries. We demonstrate that our existing library of simulations is sufficient for training, producing interpolated spectra that respond sensitively to varied ejecta parameter, post-merger time, and viewing angle inputs. We compare our interpolated spectra to the AT2017gfo spectral data, and find parameters similar to our previous inferences using broadband light curves. However, the spectral observations have significant systematic short-wavelength residuals relative to our models, which we cannot explain within our existing framework. Similar to previous studies, we argue that an additional blue component is required. We consider a radioactive heating source as a third component characterized by light, slow-moving, lanthanide-free ejecta with $M_{\rm th} = 0.003~M_\odot$, $v_{\rm th} = 0.05$c, and $\kappa_{\rm th} = 1$ cm$^2$/g. When included as part of our radiative transfer simulations, our choice of third component reprocesses blue photons into lower energies, having the opposite effect and further accentuating the blue-underluminosity disparity in our simulations. As such, we are unable to overcome short-wavelength deficits at later times using an additional radioactive heating component, indicating the need for a more sophisticated modeling treatment.

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M. Ristic, R. O’Shaughnessy, V. Villar, et. al.
Fri, 14 Apr 23
4/64

Comments: 11 pages, 7 figures, presenting at April APS session F13.00006

Inelastic Freeze-in [CL]

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http://arxiv.org/abs/2304.06072


Dark matter (DM) could be a nonthermal relic that freezes in from extremely weak, sub-Hubble annihilation and decay of Standard Model (SM) particles. The case of Dirac DM freezing in via a dark photon mediator is a well-studied benchmark for DM direct detection experiments. Here, we extend prior work to take into account the possibility that DM is pseudo-Dirac with a small mass splitting. If the mass splitting is greater than twice the electron mass but less than the dark photon mass, there will be distinct cosmological signatures. The excited state $\chi_2$ is initially produced in equal abundance to the ground state $\chi_1$. Subsequently, the excited state population decays at relatively late cosmological times, primarily via the three-body process $\chi_2 \rightarrow \chi_1 e^+ e^-$. This process injects energetic electrons into the ambient environment, providing observable signatures involving Big Bang nucleosynthesis, cosmic microwave background spectral distortions and anisotropies, and the Lyman-$\alpha$ forest. Furthermore, the ground state particles that are populated from the three-body decay receive a velocity kick, with implications for DM clustering on small scales. We find that cosmological probes and accelerator experiments are highly complementary, with future coverage of much of the parameter space of the model.

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S. Heeba, T. Lin and K. Schutz
Fri, 14 Apr 23
5/64

Comments: 15 pages, 6 figures + 1 secret doodle, comments welcome

Post-red-giant-branch Planetary Nebulae [SSA]

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http://arxiv.org/abs/2304.06355


Common envelope events have been associated with the formation of a planetary nebulae since its proposition more than forty five years ago. However, until recently there have been doubts as to whether a common envelope while the donor is ascending the red giant branch, rather than the subsequent asymptotic red giant branch, would result in a planetary nebula. There is now strong theoretical and observational evidence to suggest that some planetary nebulae are, indeed, the products of common envelope phases which occurred while the nebular progenitor was on the red giant branch. The characterisation of these systems is challenging but has the potential to reveal much about the common envelope — a critical evolutionary phase in the formation of a plethora of interesting astrophysical phenomena.

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D. Jones, T. Hillwig and N. Reindl
Fri, 14 Apr 23
6/64

Comments: 6 pages, to appear in Highlights of Spanish Astrophysics XI, Proceedings of the XV Scientific Meeting of the Spanish Astronomical Society held on September 4 0 9, 2022, in La Laguna, Spain. M. Manteiga, L. Bellot, P. Benavidez, A. de Lorenzo-Caceres, M. A. Fuente, M. J. Martinez, M. Vazquez- Acosta, C. Dafonte (eds.), 2023

Early Structure Formation from Cosmic String Loops in Light of Early JWST Observations [CEA]

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http://arxiv.org/abs/2304.06429


Cosmic strings, if they exist, source nonlinear and non-Gaussian perturbations all the way back to the time of equal matter and radiation (and earlier). Here, we compute the mass function of halos seeded by a scaling distribution of cosmic string loops, and we compare the results with the predictions of the standard Gaussian $\Lambda$CDM model. Assuming a simple linear relation between stellar mass and halo mass, we also compute the stellar mass function. The contribution of cosmic strings dominates at sufficiently high redshifts $z > z_c$ where $z_c$ depends on the mass of the halo and on the mass per unit length $\mu$ of the strings and is of the order $z_c \sim 12$ for $G\mu = 10^{-8}$. We find that strings with this value of $G\mu$ can explain the preliminary JWST data on the high redshift stellar mass density. Based on an extreme value statistic, we find that the mass of the heaviest expected string-seeded galaxy for the current JWST sky coverage is compatible with the heaviest detected galaxy. Given the uncertainties in the interpretation of the JWST data, we discuss predictions for higher redshift observations.

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H. Jiao, R. Brandenberger and A. Refregier
Fri, 14 Apr 23
7/64

Comments: 13 pages, 8 figures

A journey from the hard to the soft state: How do QPOs evolve in the 2021 outburst of GX 339-4? [HEAP]

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http://arxiv.org/abs/2304.06077


We investigated the snapshots of five NICER observations of the black hole transient GX 339-4 when the source transited from the hard state into the soft state during its outburst in 2021. In this paper, we focused our study on the evolution of quasi-periodic oscillations (QPOs) and noise components using power-density spectra. In addition, we derived hardness ratios comparing count rates above and below 2 keV. The evolution from the hard to the soft state was a somewhat erratic process showing several transitions between states that are dominated by top-flat noise and can show type-C QPOs; those that are dominated by red noise and can show type-B QPOs. From the parameters that we studied, we only found a strong correlation between the hardness ratio and the type of QPO observed. This implies that the appearance of type-B QPOs is related to a change in the accretion geometry of the system that also reflects in altered spectral properties. We also observed that the type-B QPO forms from or disintegrates into a broad peaked feature when the source comes out of or goes to the hard-intermediate state, respectively. This implies some strong decoherence in the process that creates this feature.

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H. Stiele and A. Kong
Fri, 14 Apr 23
8/64

Comments: 6 pages, 5 figures, supplementary online material as appendices (13 pages), accepted for publication in MNRAS

Prospects for detecting anisotropies and polarization of the stochastic gravitational wave background with ground-based detectors [CL]

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http://arxiv.org/abs/2304.06640


We build an analytical framework to study the observability of anisotropies and a net chiral polarization of the Stochastic Gravitational Wave Background (SGWB) with a generic network of ground-based detectors. We apply this formalism to perform a Fisher forecast of the performance of a network consisting of the current interferometers (LIGO, Virgo and KAGRA) and planned third-generation ones, such as the Einstein Telescope and Cosmic Explorer. Our results yield limits on the observability of anisotropic modes, spanning across noise- and signal-dominated regimes. We find that if the isotropic component of the SGWB has an amplitude close to the current limit, third-generation interferometers with an observation time of $10$ years can measure multipoles (in a spherical harmonic expansion) up to $\ell = 8$ with ${\cal O }\left( 10^{-3} – 10^{-2} \right)$ accuracy relative to the isotropic component, and an ${\cal O }\left( 10^{-3} \right)$ amount of net polarization. For weaker signals, the accuracy worsens as roughly the inverse of the SGWB amplitude.

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G. Mentasti, C. Contaldi and M. Peloso
Fri, 14 Apr 23
9/64

Comments: 40 pages, 7 figures, prepared for submission to JCAP

A physically derived eddy parameterization for giant planet atmospheres with application on hot-Jupiter atmospheres [EPA]

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http://arxiv.org/abs/2304.06314


We present a parameterization for the eddy diffusion profile of gas giant exoplanets based on physical phenomena and we explore how the parameterized eddy profile impacts the chemical composition, the thermal structure, the haze microphysics, and the transit spectra of 8 hot-Jupiters. Our eddy parameterization depends on the planetary intrinsic temperature (T${int}$ ), we thus evaluate how the increase of this parameter to values higher than those typically used ($\sim$100K) impacts the atmospheric structure and composition. Our investigation demonstrates that despite the strong impact of T${int}$ on the chemical composition of the deep atmosphere, the upper atmosphere is not affected for T${eq}$ $>$ 1300 K owing to high altitude quench levels at these conditions. Below this threshold, however, the larger atmospheric temperatures produced by increasing T${int}$ affect the quenched chemical composition. Our parameterization depends on two parameters, the eddy magnitude at the radiative-convective boundary (K$0$) and the corresponding magnitude at the homopause (K${top}$). We demonstrate that, when using common K$0$ and K${top}$ values among most of the different planet cases studied, we derive transit spectra consistent with Hubble Space Telescope observations. Moreover, our simulations show that increasing the eddy profile enhances the photochemical production of haze particles and reduces their average radius, thus providing a steeper UV-Visible slope. Finally, we demonstrate for WASP-39b that the James Webb Space Telescope observations provide improved constraints for the hazes and clouds and we show that both components seem necessary to interpret the combined transit spectrum from HST and JWST observations.

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A. Arfaux and P. Lavvas
Fri, 14 Apr 23
10/64

Comments: 19 pages, 12 figures

UM 462, a local Green Pea galaxy analog under the MUSE magnifying glass [GA]

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http://arxiv.org/abs/2304.06096


[ABRIGED] Stellar feedback in high-redshift galaxies plays an important role in the re-ionization epoch of the Universe. Green Pea galaxies (GPs) postulate as favorite local laboratories. However, at their typical redshift of $z\sim0.2$, the most intimate interaction between stars and surrounding ISM cannot be disentangled. Detailed studies of Blue Compact Dwarf galaxies (BCDs) are necessary to anchor our investigations on them. We present here a study in detail UM 462, a BCD with similar properties to GPs uisng high quality optical IFS data with MUSE. Total oxygen abundance by means of the direct method is 12+$\log$(O/H)$\sim$8.02 and homogenous all over the galaxy, in stark contrast with the metallicities derived from several strong line methods. The velocity field for the ionised gas presents a velocity stratification in the area towards the north with redder velocities in the high ionisation lines and bluer velocities in the low ionisation lines. This is the only area with velocity dispersions clearly above the MUSE instrumental width, and it is surrounded by two $\sim$1 kpc-long structures nicknamed \emph{the horns}. We interpret the observational evidence in that area as a fragmented super-bubble fruit of the stellar feedback and it may constitute a preferred channel for LyC photons from the youngest generation of stars to escape. The most recent SF seems to propagate from the outer to the inner parts of the galaxy, and then from east to west. We identified a supernova remnant and Wolf-Rayet stars – as traced by the red bump – that support this picture. The direction of the propagation implies the presence of younger Wolf-Rayet stars at the maximum in H$\alpha$. The ensemble of results exemplifies the potential of 2D detailed spectroscopic studies of dwarf star-forming galaxies at high spatial resolution as key reference for similar studies on primeval galaxies.

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A. Monreal-Ibero, P. Weilbacher, G. Micheva, et. al.
Fri, 14 Apr 23
11/64

Comments: 29 pages, 25 figures; resubmitted to A&A after taking the referee’s comments and suggestions into account

Fast emulation of cosmological density fields based on dimensionality reduction and supervised machine-learning [CEA]

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http://arxiv.org/abs/2304.06099


N-body simulations are the most powerful method to study the non-linear evolution of large-scale structure. However, they require large amounts of computational resources, making unfeasible their direct adoption in scenarios that require broad explorations of parameter spaces. In this work, we show that it is possible to perform fast dark matter density field emulations with competitive accuracy using simple machine-learning approaches. We build an emulator based on dimensionality reduction and machine learning regression combining simple Principal Component Analysis and supervised learning methods. For the estimations with a single free parameter, we train on the dark matter density parameter, $\Omega_m$, while for emulations with two free parameters, we train on a range of $\Omega_m$ and redshift. The method first adopts a projection of a grid of simulations on a given basis; then, a machine learning regression is trained on this projected grid. Finally, new density cubes for different cosmological parameters can be estimated without relying directly on new N-body simulations by predicting and de-projecting the basis coefficients. We show that the proposed emulator can generate density cubes at non-linear cosmological scales with density distributions within a few percent compared to the corresponding N-body simulations. The method enables gains of three orders of magnitude in CPU run times compared to performing a full N-body simulation while reproducing the power spectrum and bispectrum within $\sim 1\%$ and $\sim 3\%$, respectively, for the single free parameter emulation and $\sim 5\%$ and $\sim 15\%$ for two free parameters. This can significantly accelerate the generation of density cubes for a wide variety of cosmological models, opening the doors to previously unfeasible applications, such as parameter and model inferences at full survey scales as the ESA/NASA Euclid mission.

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M. Conceição, A. Krone-Martins, A. Silva, et. al.
Fri, 14 Apr 23
12/64

Comments: 10 pages, 6 figures. To be submitted to A&A. Comments are welcome!

LeMMINGs. VI. Connecting nuclear activity to bulge properties of active and inactive galaxies: radio scaling relations and galaxy environment [GA]

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http://arxiv.org/abs/2304.06642


Multiwavelength studies indicate that nuclear activity and bulge properties are closely related, but the details remain unclear. To study this further, we combine $Hubble~Space~Telescope$ bulge structural and photometric properties with 1.5 GHz, $e$-MERLIN nuclear radio continuum data from the LeMMINGs survey for a large sample of 173 active' galaxies (LINERs and Seyferts) andinactive’ galaxies (H IIs and absorption line galaxies, ALGs). Dividing our sample into active and inactive, they define distinct (radio core luminosity)$-$(bulge mass), L_R,core-M_,bulge, relations, with a mass turnover at M_, bulge ~ 10^(9.8 +- 0.3) M_sun (supermassive black hole mass M_BH ~ 10^(6.8 +- 0.3) M_sun), which marks the transition from AGN-dominated nuclear radio emission in more massive bulges to that mainly driven by stellar processes in low-mass bulges. None of our 10/173 bulgeless galaxies host an AGN. The AGN fraction increases with increasing M_*, bulge such that f_optical_AGN $\propto$ M_,bulge^(0.24 +- 0.06) and f_radio_AGN $\propto$ M_,bulge^(0.24 +- 0.05). Between M_*,bulge ~ 10^8.5 and 10^11.3 M_sun, f_optical_AGN steadily rises from 15 +- 4 to 80 +- 5 per cent. We find that at fixed bulge mass, the radio loudness, nuclear radio activity and the (optical and radio) AGN fraction exhibit no dependence on environment. Radio-loud hosts preferentially possess an early-type morphology than radio-quiet hosts, the two types are however indistinguishable in terms of bulge S\’ersic index and ellipticity, while results on the bulge inner logarithmic profile slope are inconclusive. We finally discuss the importance of bulge mass in determining the AGN triggering processes, including potential implications for the nuclear radio emission in nearby galaxies.

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B. Dullo, J. Knapen, R. Beswick, et. al.
Fri, 14 Apr 23
13/64

Comments: 27 pages, 15 figures, 4 tables, accepted for publication in MNRAS

Origin of neutron capture elements with the Gaia-ESO survey: the evolution of s- and r-process elements across the Milky Way [GA]

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http://arxiv.org/abs/2304.06452


We study the abundance patterns and the radial gradients of s-process elements (Y, Zr, Ba, La and Ce), r-process elements (Eu) and mixed-process elements (Mo, Nd and Pr) in the Galactic thin disc by means of a detailed two-infall chemical evolution model for the Milky Way with state-of-the-art nucleosynthesis prescriptions. We consider r-process nucleosynthesis from merging neutron stars (MNS), magneto-rotational supernovae (MR-SNe) and s-process synthesis from low- and intermediate- mass stars (LIMS) and rotating massive stars. The predictions of our model are compared with data from the sixth data release of the Gaia-ESO survey, from which we consider 62 open clusters with age > 0.1 Gyr and 1300 Milky Way disc field stars. We conclude that: i) the [Eu/Fe] vs. [Fe/H] is reproduced by both a prompt and a delayed source, but the quick source completely dominates the Eu production; ii) rotation in massive stars contribute substantially to the s-process elements of the first peak, but MNS and MR-SNe are necessary in order to reproduce the observations; iii) due to the adopted yields, our model overpredicts Pr and underpredicts Nd, while the [Mo/Fe] vs. [Fe/H] is nicely reproduced. For the radial gradients, we conclude that: i) our predicted slope of the [Fe/H] gradient is in agreement with the one observed in open clusters by Gaia-ESO and other high-resolution spectroscopic surveys. ii) The predicted slope of the [Eu/H] radial gradient is steeper than the observed one, independently on how quick the production of Eu is. We discuss the possible causes of this discrepancy in terms of both different Galaxy formation scenarios and stellar radial migration effects. iii) For all the elements belonging to the second s-process peak (Ba, La, Ce) as well as for Pr, we predict a plateau at low Galactocentric distances, which is probably due to the enhanced enrichment from LIMS in the inner regions.

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M. Molero, L. Magrini, F. Matteucci, et. al.
Fri, 14 Apr 23
14/64

Comments: 17 pages, 11 figures. Submitted to MNRAS

TOI-733 b — a planet in the small-planet radius valley orbiting a Sun-like star [EPA]

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http://arxiv.org/abs/2304.06655


We report the discovery of a hot ($T_{\rm eq}$ $\approx$ 1055 K) planet in the small planet radius valley transiting the Sun-like star TOI-733, as part of the KESPRINT follow-up program of TESS planets carried out with the HARPS spectrograph. TESS photometry from sectors 9 and 36 yields an orbital period of $P_{\rm orb}$ = $4.884765 { – 2.4e-5 } ^ { + 1.9e-5 }$ days and a radius of $R{\mathrm{p}}$ = $1.992 { – 0.090 } ^ { + 0.085 }$ $R{\oplus}$. Multi-dimensional Gaussian process modelling of the radial velocity measurements from HARPS and activity indicators, gives a semi-amplitude of $K$ = $2.23 \pm 0.26 $ m s$^{-1}$, translating into a planet mass of $M_{\mathrm{p}}$ = $5.72 { – 0.68 } ^ { + 0.70 }$ $M{\oplus}$. These parameters imply that the planet is of moderate density ($\rho_\mathrm{p}$ = $3.98 _{ – 0.66 } ^ { + 0.77 }$ g cm$^{-3}$) and place it in the transition region between rocky and volatile-rich planets with H/He-dominated envelopes on the mass-radius diagram. Combining these with stellar parameters and abundances, we calculate planet interior and atmosphere models, which in turn suggest that TOI-733 b has a volatile-enriched, most likely secondary outer envelope, and may represent a highly irradiated ocean world – one of only a few such planets around G-type stars that are well-characterised.

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I. Georgieva, C. Persson, E. Goffo, et. al.
Fri, 14 Apr 23
15/64

Comments: Accepted for publication in A&A

CATS: The Hubble Constant from Standardized TRGB and Type Ia Supernova Measurements [CEA]

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http://arxiv.org/abs/2304.06693


The Tip of the Red Giant Branch (TRGB) provides a luminous standard candle for constructing distance ladders to measure the Hubble constant. In practice its measurements via edge-detection response (EDR) are complicated by the apparent fuzziness of the tip and the multi-peak landscape of the EDR. As a result, it can be difficult to replicate due to a case-by-case measurement process. Previously we optimized an unsupervised algorithm, Comparative Analysis of TRGBs (CATs), to minimize the variance among multiple halo fields per host without reliance on individualized choices, achieving state-of-the-art $\sim$ $<$ 0.05 mag distance measures for optimal data. Further, we found an empirical correlation at 5$\sigma$ confidence in the GHOSTS halo survey between our measurements of the tip and their contrast ratios (ratio of stars 0.5 mag just below and above the tip), useful for standardizing the apparent tips at different host locations. Here, we apply this algorithm to an expanded sample of SN Ia hosts to standardize these to multiple fields in the geometric anchor, NGC 4258. In concert with the Pantheon$+$ SN Ia sample, this analysis produces a (baseline) result of $H_0= 73.22 \pm 2.06$ km/s/Mpc. The largest difference in $H_0$ between this and similar studies employing the TRGB derives from corrections for SN survey differences and local flows used in most recent SN Ia compilations but which were absent in earlier studies. SN-related differences total $\sim$ 2.0 km/s/Mpc. A smaller share, $\sim$ 1.4 km/s/Mpc, results from the inhomogeneity of the TRGB calibration across the distance ladder. We employ a grid of 108 variants around the optimal TRGB algorithm and find the median of variants is $72.94\pm1.98$ km/s/Mpc with an additional uncertainty due to algorithm choices of 0.83 km/s/Mpc. None of these TRGB variants result in $H_0$ less than 71.6 km/s/Mpc.

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D. Scolnic, A. Riess, J. Wu, et. al.
Fri, 14 Apr 23
16/64

Comments: Submitted to ApJL, comments welcome

On the anti-correlation between pericentric distance and inner dark matter density of Milky Way's dwarf spheroidal galaxies [GA]

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http://arxiv.org/abs/2304.06611


An anti-correlation between the central density of the dark matter halo ($\rho_{150,\ {\rm DM}}$) and the pericentric distances ($r_{p}$) of the Milky Way’s (MW’s) dwarf spheroidal galaxies (dSphs) has been reported in the literature. The existence and origin of such anti-correlation is however controversial, one possibility being that only the densest dSphs can survive the tidal field towards the centre of our Galaxy. In this work, we place particular emphasis on quantifying the statistical significance of such anti-correlation, by using available literature data in order to explore its robustness under different assumptions on the MW gravitational potential, and for various derivations of $\rho_{150}$ and $r_{p}$. We consider models in which the MW is isolated and has a low ($8.8\times10^{11}\,M_{\odot}$) and high ($1.6\times10^{12}\, M_{\odot}$) halo mass, respectively, as well as configurations in which the MW’s potential is perturbed by a Large Magellanic Cloud (LMC) infall. We find that, while data generally support models in which the dSphs’ central DM density decreases as a function of their pericentric radius, this anti-correlation is statistically significant at $3\sigma$ level only in $\sim$12$\%$ of the combinations of $\rho_{150}$ and $r_{p}$ explored. Moreover, including the impact of the LMC’s infall onto the MW weakens or even washes away this anti-correlation, with respect to models in which the MW is isolated. Our results suggest that the strength and existence of such anti-correlation is still debatable: exploring it with high-resolution simulations including baryonic physics and different DM flavours will help us to understand its emergence.

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S. Cardona-Barrero, G. Battaglia, C. Nipoti, et. al.
Fri, 14 Apr 23
17/64

Comments: 10 pages, 3 figures. Accepted for publication in MNRAS

Direct observations of the atomic-molecular phase transition in the Milky Way's nuclear wind [GA]

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http://arxiv.org/abs/2304.06356


Hundreds of high-velocity atomic gas clouds exist above and below the Galactic Centre, with some containing a molecular component. However, the origin of these clouds in the Milky Way’s wind is unclear. This paper presents new high-resolution MeerKAT observations of three atomic gas clouds and studies the relationship between the atomic and molecular phases at $\sim 1$ pc scales. The clouds’ atomic hydrogen column densities, $N_{\mathrm{HI}}$, are less than a $\mbox{few}\times 10^{20}$ cm$^{-2}$, but the two clouds closest to the Galactic Centre nonetheless have detectable CO emission. This implies the presence of H${2}$ at levels of $N{\mathrm{HI}}$ at least a factor of ten lower than in the typical Galactic interstellar medium. For the cloud closest to the Galactic Centre, there is little correlation between the $N_{\mathrm{HI}}$ and the probability that it will harbour detectable CO emissions. In contrast, for the intermediate cloud, detectable CO is heavily biased toward the highest values of $N_{\mathrm{HI}}$. The cloud most distant from the Galactic Centre has no detectable CO at similar $N_{\mathrm{HI}}$ values. Moreover, we find that the two clouds with detectable CO are too molecule-rich to be in chemical equilibrium, given the depths of their atomic shielding layers, which suggests a scenario whereby these clouds consist of pre-existing molecular gas from the disc that the Galactic wind has swept up, and that is dissociating into atomic hydrogen as it flows away from the Galaxy. We estimate that entrained molecular material of this type has a $\sim \mathrm{few}-10$ Myr lifetime before photodissociating.

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K. Noon, M. Krumholz, E. Teodoro, et. al.
Fri, 14 Apr 23
18/64

Comments: 11 pages, 6 figures, 2 tables. Submitted to MNRAS

Flashlights: Properties of Highly Magnified Images Near Cluster Critical Curves in the Presence of Dark Matter Subhalos [CEA]

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http://arxiv.org/abs/2304.06064


Dark matter subhalos with extended profiles and density cores, and globular stars clusters of mass $10^6-10^8 M_\odot$, that live near the critical curves in galaxy cluster lenses can potentially be detected through their lensing magnification of stars in background galaxies. In this work we study the effect such subhalos have on lensed images, and compare to the case of more well studied microlensing by stars and black holes near critical curves. We find that the cluster density gradient and the extended mass distribution of subhalos are important in determining image properties. Both lead to an asymmetry between the image properties on the positive and negative parity sides of the cluster that is more pronounced than in the case of microlensing. For example, on the negative parity side, subhalos with cores larger than about $50\,$pc do not generate any images with magnification above $\sim 100$ outside of the immediate vicinity of the cluster critical curve. We discuss these factors using analytical and numerical analysis, and exploit them to identify observable signatures of subhalos: subhalos create pixel-to-pixel flux variations of $\gtrsim 0.1$ magnitudes, on the positive parity side of clusters. These pixels tend to cluster around (otherwise invisible) subhalos. Unlike in the case of microlensing, signatures of subhalo lensing can be found up to $1”$ away from the critical curves of massive clusters.

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L. Williams, P. Kelly, T. Treu, et. al.
Fri, 14 Apr 23
19/64

Comments: ApJ, submitted, 21 pages, 17 figures

A Contribution of the HAWC Observatory to the TeV era in the High Energy Gamma-Ray Astrophysics: The case of the TeV-Halos [HEAP]

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http://arxiv.org/abs/2304.06271


We present a short overview of the TeV-Halos objects as a discovery and a relevant contribution of the High Altitude Water \v{C}erenkov (HAWC) observatory to TeV astrophysics. We discuss history, discovery, knowledge, and the next step through a new and more detailed analysis than the original study in 2017. TeV-Halos will contribute to resolving the problem of the local positron excess observed on the Earth. To clarify the latter, understanding the diffusion process is mandatory.

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R. Torres-Escobedo, H. Zhou, E. Fuente, et. al.
Fri, 14 Apr 23
20/64

Comments: Work presented in the 21st International Symposium on Very High Energy Cosmic Ray Interactions(ISVHECRI 2022) as part of the Ph. D. Thesis of Ramiro Torres-Escobedo (SJTU, Shanghai, China). Accepted for publication in SciPost Physics Proceedings (ISSN 2666-4003). 11 pages, 3 Figures. Short overview of HAWC and TeV Halos objects until 2022

The Most Obscured AGNs in the XMM-SERVS Fields [GA]

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http://arxiv.org/abs/2304.06065


We perform X-ray spectral analyses to derive characteristics (e.g., column density, X-ray luminosity) of $\approx$10,200 active galactic nuclei (AGNs) in the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS), which was designed to investigate the growth of supermassive black holes across a wide dynamic range of cosmic environments. Using physical torus models (e.g., Borus02) and a Bayesian approach, we uncover 22 representative Compton-thick (CT; $N_{\rm H} \;>\; 1.5\times10^{24}\; \rm cm^{-2}$) AGN candidates with good signal-to-noise ratios as well as a large sample of 136 heavily obscured AGNs. We also find an increasing CT fraction (\fct ) from low ($z<0.75$) to high ($z>0.75$) redshift. Our CT candidates tend to show hard X-ray spectral shapes and dust extinction in their SED fits, which may shed light on the connection between AGN obscuration and host-galaxy evolution.

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W. Yan, W. Brandt, F. Zou, et. al.
Fri, 14 Apr 23
21/64

Comments: 12 pages, 9 figures, accepted for publication in ApJ

Pure Spectroscopic Constraints on UV Luminosity Functions and Cosmic Star Formation History From 25 Galaxies at $z_\mathrm{spec}=8.61-13.20$ Confirmed with JWST/NIRSpec [GA]

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http://arxiv.org/abs/2304.06658


We present pure spectroscopic constraints on the UV luminosity functions and cosmic star formation rate (SFR) densities from 25 galaxies at $z_\mathrm{spec}=8.61-13.20$. By reducing the JWST/NIRSpec spectra taken in multiple programs of ERO, ERS, GO, and DDT with our analysis technique, we independently confirm 16 galaxies at $z_\mathrm{spec}=8.61-11.40$ including new redshift determinations, and a bright interloper at $z_\mathrm{spec}=4.91$ that was claimed as a photometric candidate at z~16. In conjunction with nine galaxies at redshifts up to $z_\mathrm{spec}=13.20$ in the literature, we make a sample of 25 spectroscopically-confirmed galaxies in total and carefully derive the best estimates and lower limits of the UV luminosity functions. These UV luminosity function constraints are consistent with the previous photometric estimates within the uncertainties and indicate mild redshift evolution towards z~12 showing tensions with some theoretical models of rapid evolution. With these spectroscopic constraints, we obtain firm lower limits of the cosmic SFR densities and spectroscopically confirm a high SFR density at z~12 beyond the constant star-formation efficiency models, which supports earlier claims from the photometric studies. While there are no spectroscopically-confirmed galaxies with very large stellar masses violating the $\Lambda$CDM model due to the removal of the bright interloper, we confirm star-forming galaxies at $z_\mathrm{spec}=11-13$ with stellar masses much higher than model predictions. Our results indicate possibilities of high star-formation efficiency (>5%), hidden AGN, top-heavy initial mass function (possibly with Pop-III), and large scatter/variance. Having these successful and unsuccessful spectroscopy results, we suggest observational strategies for efficiently removing low redshift interlopers for future JWST programs.

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Y. Harikane, K. Nakajima, M. Ouchi, et. al.
Fri, 14 Apr 23
22/64

Comments: 27 pages, 18 figures, submitted to ApJ

Stability of relativistic tidal response against small potential modification [CL]

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http://arxiv.org/abs/2304.04551


The tidal response of compact objects in an inspiraling binary system is measured by a set of tidal Love and dissipation numbers imprinted in the gravitational waveforms. While a four-dimensional black hole in vacuum within General Relativity has vanishing Love numbers, a black hole in alternative theories of gravity can acquire non-vanishing Love numbers. The dissipation numbers may quantify Planckian corrections at the horizon scale. These properties will allow a test of classical theories of gravity in the strong-field regime with gravitational-wave observation. Since black holes are not in the exact vacuum environment in astrophysical situations, the following question arises: can the environment affect the tidal response? In this paper, we investigate the stability of the tidal response of a Schwarzschild black hole for frequency-dependent tidal-field perturbations against a small modification of the background. Our analysis relies on the scattering theory, which overcomes difficulties in defining the relativistic tidal Love numbers. The tidal Love and dissipation numbers can be extracted from the phase shift of sufficiently low-frequency scattering waves. We show that the tidal Love numbers are sensitive to the property of the modification. Therefore, we need careful consideration of the environment around the black hole in assessing the deviation of the underlying theory of gravity from General Relativity with the Love numbers. The modification has less impact on the dissipation numbers, indicating that quantifying the existence of the event horizon with them is not spoiled. We also demonstrate that in a composite system, i.e., a compact object with environmental effects, the Love and dissipation numbers are approximately determined by the sum of the numbers of each component.

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T. Katagiri, H. Nakano and K. Omukai
Fri, 14 Apr 23
23/64

Comments: 45 pages, 23 figures

Stochastic gravitational wave background constraints from Gaia DR3 astrometry [CEA]

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http://arxiv.org/abs/2304.06350


Astrometric surveys can be used to constrain the stochastic gravitational wave background (SGWB) at very low frequencies. We use proper motion data provided by Gaia DR3 to fit a generic dipole+quadrupole field. We analyse several quasar-based datasets and discuss their purity and idoneity to set constraints on gravitational waves. For the cleanest dataset, we derive an upper bound on the (frequency-integrated) energy density of the SGWB $h_{70}^2\Omega_{\rm GW}\lesssim 0.087$ for $4.2\times 10^{-18}~\mathrm{Hz}\lesssim f\lesssim 1.1\times 10^{-8}~\mathrm{Hz}$. We also reanalyse previous VLBI-based data to set the constraint $h_{70}^2\Omega_{\rm GW}\lesssim 0.024$ for $5.8\times 10^{-18}~\mathrm{Hz}\lesssim f\lesssim 1.4\times 10^{-9}~\mathrm{Hz}$ under the same formalism, standing as the best astrometric constraint on GWs. Based on our results, we discuss the potential of future Gaia data releases to impose tighter constraints.

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S. Jaraba, J. García-Bellido, S. Kuroyanagi, et. al.
Fri, 14 Apr 23
24/64

Comments: 15 pages, 7 figures

Quasi Real-Time Autonomous Satellite Detection and Orbit Estimation [IMA]

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http://arxiv.org/abs/2304.06227


A method of near real-time detection and tracking of resident space objects (RSOs) using a convolutional neural network (CNN) and linear quadratic estimator (LQE) is proposed. Advances in machine learning architecture allow the use of low-power/cost embedded devices to perform complex classification tasks. In order to reduce the costs of tracking systems, a low-cost embedded device will be used to run a CNN detection model for RSOs in unresolved images captured by a gray-scale camera and small telescope. Detection results computed in near real-time are then passed to an LQE to compute tracking updates for the telescope mount, resulting in a fully autonomous method of optical RSO detection and tracking. Keywords: Space Domain Awareness, Neural Networks, Real-Time, Object Detection, Embedded Systems.

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J. Jordan, D. Posada, M. Gillette, et. al.
Fri, 14 Apr 23
25/64

Comments: SPIE Defense and Commercial 2023, Orlando, FL

Morphological asymmetries of quasar host galaxies with Subaru Hyper Suprime-Cam [GA]

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http://arxiv.org/abs/2304.06090


How does the host galaxy morphology influence a central quasar or vice versa? We address this question by measuring the asymmetries of 2424 SDSS quasar hosts at $0.2<z<0.8$ using broad-band ($grizy$) images from the Hyper Suprime-Cam Subaru Strategic Program. Control galaxies (without quasars) are selected by matching the redshifts and stellar masses of the quasar hosts. A two-step pipeline is run to decompose the PSF and \sersic\ components, and then measure asymmetry indices ($A_{\rm CAS}$, $A_{\rm outer}$, and $A_{\rm shape}$) of each quasar host and control galaxy. We find a mild correlation between host asymmetry and AGN bolometric luminosity ($L_{\rm bol}$) for the full sample (spearman correlation of 0.37) while a stronger trend is evident at the highest luminosities ($L_{\rm bol}>45$). This then manifests itself into quasar hosts being more asymmetric, on average, when they harbor a more massive and highly accreting black hole. The merger fraction also positively correlates with $L_{\rm bol}$ and reaches up to 35\% for the most luminous. Compared to control galaxies, quasar hosts are marginally more asymmetric (excess of 0.017 in median at 9.4$\sigma$ level) and the merger fractions are similar ($\sim 16.5\%$). We quantify the dependence of asymmetry on optical band which demonstrates that mergers are more likely to be identified with the bluer bands and the correlation between $L_{\rm bol}$ and asymmetry is also stronger in such bands. We stress that the band dependence, indicative of a changing stellar population, is an important factor in considering the influence of mergers on AGN activity.

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S. Tang, J. Silverman, H. Yesuf, et. al.
Fri, 14 Apr 23
26/64

Comments: 27 pages, 28 figures

The role of previous generations of stars in triggering star formation and driving gas dynamics [GA]

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http://arxiv.org/abs/2304.06659


We present hydrodynamic and magnetohydrodynamic (MHD) simulations of sub galactic regions including photoionising and supernova feedack. We aim to improve the initial conditions of our region extraction models by including an initial population of stars. We also investigate the reliability of extracting regions in simulations, and show that with a good choice of region, results are comparable with using a larger region for the duration of our simulations. Simulations of star formation on molecular cloud scales typically start with a turbulent cloud of gas, from which stars form and then undergo feedback. In reality, a typical cloud or region within a galaxy may already include, or reside near some population of stars containing massive stars undergoing feedback. We find the main role of a prior population is triggering star formation, and contributing to gas dynamics. Early time supernova from the initial population are important in triggering new star formation and driving gas motions on larger scales above 100 pc, whilst the ionising feedback contribution from the initial population has less impact, since many members of the initial population have cleared out gas around them in the prior model. In terms of overall star formation rates though, the initial population has a relatively small effect, and the feedback does not for example suppress subsequent star formation. We find that MHD has a relatively larger impact than initial conditions, reducing the star formation rate by a factor of 3 at later times.

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N. Herrington, C. Dobbs and T. Bending
Fri, 14 Apr 23
27/64

Comments: 12 pages, 10 figures

Revisiting Friedmann-like cosmology with torsion: newest constraints from high-redshift observations [CEA]

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http://arxiv.org/abs/2304.06425


As one of the possible extensions of Einstein’s General Theory of Relativity, it has been recently suggested that the presence of spacetime torsion could solve problems of the very early and the late-time universe undergoing accelerating phases. In this paper, we use the latest observations of high-redshift data, coming from multiple measurements of quasars and baryon acoustic oscillations, to phenomenologically constrain such cosmological model in the framework of Einstein-Cartan (EC) endowed with spacetime torsion. Such newly compiled quasar datasets in the cosmological analysis is crucial to this aim, since it will extend the Hubble diagram to high-redshift range in which predictions from different cosmologies can be distinguished. Our results show that out of all the candidate models, the torsion plus cosmological constant model is strongly favoured by the current high-redshift data, where torsion itself would be expected to yield the current cosmic acceleration. Specially, in the framework of Friedmann-like cosmology with torsion, the determined Hubble constant is in very good agreement with that derived from the Planck 2018 CMB results. On the other hand, our results are compatible with zero spatial curvature and there is no significant deviation from flat spatial hypersurfaces. Finally, we check the robustness of high-redshift observations by placing constraints on the torsion parameter $\alpha$, which is strongly consistent with other recent works focusing on torsion effect on the primordial helium-4 abundance.

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T. Liu, Z. Liu, J. Wang, et. al.
Fri, 14 Apr 23
28/64

Comments: 23 pages, 5 figures

Universal Gravitational Wave Signatures of Cosmological Solitons [CEA]

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http://arxiv.org/abs/2304.06709


Cosmological solitonic objects such as monopoles, cosmic strings, domain walls, oscillons and Q-balls often appear in theories of the early Universe. We demonstrate that such scenarios are generically accompanied by a novel production source of gravitational waves stemming from soliton isocurvature perturbations. The resulting induced universal gravitational waves (UGWs) reside at lower frequencies compared to gravitational waves typically associated with soliton formation. We show that UGWs from axion-like particle (ALP) oscillons, originating from ALP misalignment, extend the frequency range of produced gravitational waves by more than two orders of magnitude regardless of the ALP mass and decay constant and can be observable in upcoming gravitational wave experiments. UGWs open a new route for gravitational wave signatures in broad classes of cosmological theories.

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K. Lozanov, M. Sasaki and V. Takhistov
Fri, 14 Apr 23
29/64

Comments: 8 pages, 2 figures

Rotation curves of galaxies in GR [GA]

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http://arxiv.org/abs/2304.06151


It has been suggested that the observed flat rotation curves of disk galaxies can be a peculiar effect of General Relativity (GR) rather than evidence for the presence of dark matter (DM) halos in Newtonian gravity. In Ciotti (2022) the problem has been quantitatively addressed by using the well known weak-field, low-velocity gravitomagnetic limit of GR, for realistic exponential baryonic (stellar) disks. As expected, the resulting GR and Newtonian rotation curves are indistinguishable, with GR corrections at all radii of the order of $v^2/c^2\approx 10^{-6}$. Here we list some astrophysical problems that must be faced if the existence of DM halos is attributed to a misinterpretation of weak field effects of GR.

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L. Ciotti
Fri, 14 Apr 23
30/64

Comments: 4 pages, no figures, Proceedings of EAS2022, Symposium S3, to be published on Memorie della SAIt