Low-period spacing core-helium burning giants: `hot subdwarf analogues'? [SSA]

http://arxiv.org/abs/2305.10578


Global stellar oscillations probe the internal structure of stars. In low- to intermediate-mass red giants, these oscillations provide signatures from both the outer regions of the star as well as from the core. These signatures are imprinted in e.g. the frequency of maximum oscillation power, and in the differences in periods of non-radial oscillations (period spacings), respectively. In core helium burning giants with masses below about 1.7 solar masses, i.e. stars that have gone through a helium flash, the asymptotic period spacings take values of about 220 -350 s at frequency of maximum oscillation power of $\sim$30-50 $\mu$Hz. A set of stars with asymptotic period spacings lower than about 200 s at similar frequencies separations has recently been discovered by Elsworth and collaborators. In this work, we present a hypothesis for the formation scenario of these stars. We find that these stars can be the result of a mass-loss event at the end of the red-giant branch phase of stars massive enough to not have a degenerate core, i.e. one of the scenarios to form hot subdwarf stars. Therefore, these stars can be classified as `hot subdwarf analogues’. Interestingly, if mass loss continues gradually during the core helium burning phase, these stars turn hotter and denser, and could, therefore, be hot subdwarf progenitors as they shed more of their envelope.

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S. Hekker, Y. Elsworth, T. Braun, et. al.
Fri, 19 May 23
3/46

Comments: Scientific content recommended for publication in MNRAS

The First X-ray Polarization Observation of the Black Hole X-ray Binary 4U 1630-47 in the Steep Power Law State [HEAP]

http://arxiv.org/abs/2305.10630


The Imaging X-ray Polarimetry Explorer (IXPE) observed the black hole X-ray binary 4U 1630-47 in the steep power law (or very high) state. The observations reveal a linear polarization degree of the 2-8 keV X-rays of 6.8 +/- 0.2 % at a position angle of 21{\deg}.3 +/- 0{\deg}.9 East of North (all errors at 1{\sigma} confidence level). Whereas the polarization degree increases with energy, the polarization angle stays constant within the accuracy of our measurements. We compare the polarization of the source in the steep power-law state with the previous IXPE measurement of the source in the high soft state. We find that even though the source flux and spectral shape are significantly different between the high soft state and the steep power-law state, their polarization signatures are similar. Assuming that the polarization of both the thermal and power-law emission components are constant over time, we estimate the power-law component polarization to be 6.8-7.0% and note that the polarization angle of the thermal and power-law components must be approximately aligned. We discuss the implications for the origin of the power-law component and the properties of the emitting plasma.

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N. Cavero, L. Marra, H. Krawczynski, et. al.
Fri, 19 May 23
4/46

Comments: 14 pages, 2 tables, 6 figures

Primordial black holes from null energy condition violation during inflation [CL]

http://arxiv.org/abs/2305.10933


The violation of the null energy condition (NEC) is closely related to potential solutions for the cosmological singularity problem and may therefore play a crucial role in the very early universe. We explore a novel approach to generate primordial black holes (PBHs) via the violation of the NEC in a single-field inflationary scenario. In our scenario, the universe transitions from a first slow-roll inflation stage with a Hubble parameter H = Hinf1 to a second slow-roll inflation stage with H = Hinf2 > Hinf1, passing through an intermediate stage of NEC violation. The resulting primordial scalar power spectrum is naturally enhanced by the NEC violation at a certain wavelength. As a result, PBHs with masses and abundances of observational interest can be produced in our scenario. We also examine the phenomenological signatures of scalar-induced gravitational waves (SIGWs). Our work highlights the significance of utilizing a combination of PBHs, SIGWs, and primordial gravitational waves as a powerful probe for exploring the NEC violation during inflation.

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Y. Cai, M. Zhu and Y. Piao
Fri, 19 May 23
5/46

Comments: 8 pages, 5 figures

The Pristine Inner Galaxy Survey (PIGS) VII: a discovery of the first inner Galaxy CEMP-r/s star [SSA]

http://arxiv.org/abs/2305.10717


Well-studied very metal-poor (VMP, [Fe/H] < -2 ) stars in the inner Galaxy are few in number, and they are of special interest because they are expected to be among the oldest stars in the MilkyWay. We present high-resolution spectroscopic follow-up of the carbon-enhanced metal-poor (CEMP) star Pristine_184237.56-260624.5 (hereafter Pr184237) identified in the Pristine Inner Galaxy Survey. This star has an apocentre of about 2 kpc. Its atmospheric parameters (Teff = 5100 K, log g = 2.0, [Fe/H] = -2.60) were derived based on the non-local thermodynamic equilibrium (NLTE) line formation. We determined abundances for 32 elements, including 15 heavy elements beyond the iron group. The NLTE abundances were calculated for 13 elements from Na to Pb. Pr184237 is strongly enhanced in C, N, O, and both s- and r-process elements from Ba to Pb; it reveals a low carbon isotope ratio of 12C/13C = 7. The element abundance pattern in the Na-Zn range is typical of halo stars. With [Ba/Eu] = 0.32, Pr184237 is the first star of the CEMP-r/s subclass identified in the inner Galaxy. Variations in radial velocity suggest binarity. We tested whether a pollution by the s- or i-process material produced in the more massive and evolved companion can form the observed abundance pattern and find that an i-process in the asymptotic giant branch star with a progenitor mass of 1.0-2.0 Msun can be the solution.

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L. Mashonkina, A. Arentsen, D. Aguado, et. al.
Fri, 19 May 23
6/46

Comments: 15 pages, 11 figures, 5 tables, MNRAS, accepted

MiraBest: A Dataset of Morphologically Classified Radio Galaxies for Machine Learning [IMA]

http://arxiv.org/abs/2305.11108


The volume of data from current and future observatories has motivated the increased development and application of automated machine learning methodologies for astronomy. However, less attention has been given to the production of standardised datasets for assessing the performance of different machine learning algorithms within astronomy and astrophysics. Here we describe in detail the MiraBest dataset, a publicly available batched dataset of 1256 radio-loud AGN from NVSS and FIRST, filtered to $0.03 < z < 0.1$, manually labelled by Miraghaei and Best (2017) according to the Fanaroff-Riley morphological classification, created for machine learning applications and compatible for use with standard deep learning libraries. We outline the principles underlying the construction of the dataset, the sample selection and pre-processing methodology, dataset structure and composition, as well as a comparison of MiraBest to other datasets used in the literature. Existing applications that utilise the MiraBest dataset are reviewed, and an extended dataset of 2100 sources is created by cross-matching MiraBest with other catalogues of radio-loud AGN that have been used more widely in the literature for machine learning applications.

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F. Porter and A. Scaife
Fri, 19 May 23
7/46

Comments: 14 pages, 2 figures, accepted by RASTI

Cogenesis of matter and dark matter from triplet fermion seesaw [CL]

http://arxiv.org/abs/2305.11138


We propose a simple model in the type-III seesaw framework to explain the recently reported W-mass anomaly by CDF-II collaboration, neutrino mass, asymmetric dark matter, and baryon asymmetry of the Universe. We extend the standard model with a vector-like singlet lepton ($\chi$) and a hypercharge zero scalar triplet ($\Delta$) in addition to three hypercharge zero triplet fermions($\Sigma_i~,i=1,2,3$). A $Z_2$ symmetry is imposed under which $\chi$ and $\Delta$ are odd, while all other particles are even. As a result, the lightest $Z_2$ odd particle $\chi$ behaves as a candidate of dark matter. In the early Universe, the CP-violating out-of-equilibrium decay of heavy triplet fermions to the Standard Model lepton ($L$) and Higgs ($H$) generate a net lepton asymmetry, while that of triplet fermions to $\chi$ and $\Delta$ generate a net asymmetric dark matter. The lepton asymmetry is converted to the required baryon asymmetry of the Universe via the electroweak sphalerons, while the asymmetry in $\chi$ remains as a dark matter relic that we observe today. We introduce a singlet scalar $\phi$, with mass $m_\phi < m_\chi$, which not only assists to deplete the symmetric component of $\chi$ through the annihilation process: $\bar{\chi} \chi \to \phi \phi$ but also paves a path to detect dark matter $\chi$ at direct search experiments through $\phi-H$ mixing. The $Z_2$ symmetry is broken softly resulting in an unstable asymmetric dark matter with mass ranging from a few MeV to a few tens of GeV. The softly broken $Z_2$ symmetry also induces a vacuum expectation value (vev) of $\Delta$ due to which the asymmetry in $\Delta$ disappears. Moreover, the vev of $\Delta$ enhances the W-boson mass as reported by CDF-II collaboration with $7\sigma$ statistical significance, while keeping the $Z$-boson mass intact.

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S. Mahapatra, P. Paul, N. Sahu, et. al.
Fri, 19 May 23
8/46

Comments: 33 pages, 19 captioned figures

The Photon Content of the Neutron [CL]

http://arxiv.org/abs/2305.10497


In this work, we complete our CT18qed study with the neutron’s photon parton distribution function (PDF), which is essential for the nucleus scattering phenomenology. Two methods, CT18lux and CT18qed, based on the LUXqed formalism and the DGLAP evolution, respectively, to determine the neutron’s photon PDF have been presented. Various low-$Q^2$ non-perturbative variations have been carefully examined, which are treated as additional uncertainties on top of those induced by quark and gluon PDFs. The impacts of the momentum sum rule as well as isospin symmetry violation have been explored, and turn out to be negligible. A detailed comparison with other neutron’s photon PDF sets has been performed, which shows a great improvement in the precision and a reasonable uncertainty estimation in our results. Finally, two phenomenological implications are demonstrated with photon-initiated processes: neutrino-nucleus $W$-boson production, which is important for the near-future TeV–PeV neutrino observations, and the axion-like particle production at a high-energy muon beam-dump experiment.

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K. Xie, B. Zhou and T. Hobbs
Fri, 19 May 23
9/46

Comments: 34 pages, 22 figures

Protocols for healing radiation-damaged single-photon detectors suitable for space environment [CL]

http://arxiv.org/abs/2305.10959


Single-photon avalanche detectors (SPADs) are well-suited for satellite-based quantum communication because of their advantageous operating characteristics as well as their relatively straightforward and robust integration into satellite payloads. However, space-borne SPADs will encounter damage from space radiation, which usually manifests itself in the form of elevated dark counts. Methods for mitigating this radiation damage have been previously explored, such as thermal and optical (laser) annealing. Here we investigate in a lab, using a CubeSat payload, laser annealing protocols in terms of annealing laser power and annealing duration, for their possible later use in orbit. Four Si SPADs (Excelitas SLiK) irradiated to an equivalent of 10 years in low Earth orbit exhibit very high dark count rates (>300 kcps at -22 C operating temperature) and significant saturation effects. We show that annealing them with optical power between 1 and 2 W yields reduction in dark count rate by a factor of up to 48, as well as regaining SPAD sensitivity to a very faint optical signal (on the order of single photon) and alleviation of saturation effects. Our results suggest that an annealing duration as short as 10 seconds can reduce dark counts, which can be beneficial for power-limited small-satellite quantum communication missions. Overall, annealing power appears to be more critical than annealing duration and number of annealing exposures.

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J. Krynski, N. Sultana, Y. Lee, et. al.
Fri, 19 May 23
10/46

Comments: 6 pages, 9 figures, work presented at IEEE Nuclear and Space Radiation Effects Conference 2022, prepared for submission to IEEE Transactions on Nuclear Science

Precise self-calibration of interloper bias in spectroscopic surveys [CEA]

http://arxiv.org/abs/2305.10487


Interloper contamination due to line misidentification is an important issue in the future low-resolution spectroscopic surveys. We realize that the algorithm previously used for photometric redshift self-calibration, with minor modifications, can be particularly applicable to calibrate the interloper bias. In order to explore the robustness of the modified self-calibration algorithm, we construct the mock catalogues based on China Space Station Telescope (CSST), taking two main target emission lines, H$\alpha$ and [O III]. The self-calibration algorithm is tested in cases with different interloper fractions at 1 per cent, 5 per cent and 10 per cent. We find that the interloper fraction and mean redshift in each redshift bin can be successfully reconstructed at the level of ~ 0.002 and ~ 0.001(1+z), respectively. We also find the impact of the cosmic magnification can be significant, which is usually ignored in previous works, and therefore propose a convenient and efficient method to eliminate it. Using the elimination method, we show that the calibration accuracy can be effectively recovered with slightly larger uncertainty.

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H. Peng and Y. Yu
Fri, 19 May 23
11/46

Comments: 9 pages, 9 figures, submitted to MNRAS

X-Ray Tests of General Relativity with Black Holes [CL]

http://arxiv.org/abs/2305.10715


General relativity is one of the pillars of modern physics. For decades, the theory has been mainly tested in the weak field regime with experiments in the Solar System and radio observations of binary pulsars. Until 2015, the strong field regime was almost completely unexplored. Thanks to new observational facilities, the situation has dramatically changed in the last few years. Today we have gravitational wave data of the coalesce of stellar-mass compact objects from the LIGO-Virgo-KAGRA Collaboration, images at mm wavelengths of the supermassive black holes in M87$^$ and SgrA$^$ from the Event Horizon Telescope Collaboration, and X-ray data of accreting compact objects from a number of X-ray missions. Gravitational wave tests and black hole imaging tests are certainly more popular and are discussed in other articles of this Special Issue. The aim of the present manuscript is to provide a pedagogical review on X-ray tests of general relativity with black holes and to compare this kind of tests with those possible with gravitational wave data and black hole imaging.

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C. Bambi
Fri, 19 May 23
12/46

Comments: 16 pages, 5 figures. Invited contribution for the Special Issue “Role of Black Holes in Testing Modified Theories of Gravity” for Symmetry (Ed. Rahul Kumar Walia)

Quijote-PNG: The Information Content of the Halo Mass Function [CEA]

http://arxiv.org/abs/2305.10597


We study signatures of primordial non-Gaussianity (PNG) in the redshift-space halo field on non-linear scales, using a combination of three summary statistics, namely the halo mass function (HMF), power spectrum, and bispectrum. The choice of adding the HMF to our previous joint analysis of power spectrum and bispectrum is driven by a preliminary field-level analysis, in which we train graph neural networks on halo catalogues to infer the PNG $f_\mathrm{NL}$ parameter. The covariance matrix and the responses of our summaries to changes in model parameters are extracted from a suite of halo catalogues constructed from the Quijote-PNG N-body simulations. We consider the three main types of PNG: local, equilateral and orthogonal. Adding the HMF to our previous joint analysis of power spectrum and bispectrum produces two main effects. First, it reduces the equilateral $f_\mathrm{NL}$ predicted errors by roughly a factor $2$, while also producing notable, although smaller, improvements for orthogonal PNG. Second, it helps break the degeneracy between the local PNG amplitude, $f_\mathrm{NL}^\mathrm{local}$, and assembly bias, $b_{\phi}$, without relying on any external prior assumption. Our final forecasts for PNG parameters are $\Delta f_\mathrm{NL}^\mathrm{local} = 40$, $\Delta f_\mathrm{NL}^\mathrm{equil} = 210$, $\Delta f_\mathrm{NL}^\mathrm{ortho} = 91$, on a cubic volume of $1 \left( {\rm Gpc}/{\rm h} \right)^3$, with a halo number density of $\bar{n}\sim 5.1 \times 10^{-5}~h^3\mathrm{Mpc}^{-3}$, at $z = 1$, and considering scales up to $k_\mathrm{max} = 0.5~h\,\mathrm{Mpc}^{-1}$.

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G. Jung, A. Ravenni, M. Baldi, et. al.
Fri, 19 May 23
13/46

Comments: 17 pages, 11 figures

A spectroscopic thermometer: individual vibrational band spectroscopy with the example of OH in the atmosphere of WASP-33b [EPA]

http://arxiv.org/abs/2305.11071


Individual vibrational band spectroscopy presents an opportunity to examine exoplanet atmospheres in detail by distinguishing where the vibrational state populations of molecules differ from the current assumption of a Boltzmann distribution. Here, retrieving vibrational bands of OH in exoplanet atmospheres is explored using the hot Jupiter WASP-33b as an example. We simulate low-resolution spectroscopic data for observations with the JWST’s NIRSpec instrument and use high resolution observational data obtained from the Subaru InfraRed Doppler instrument (IRD). Vibrational band-specific OH cross section sets are constructed and used in retrievals on the (simulated) low and (real) high resolution data. Low resolution observations are simulated for two WASP-33b emission scenarios: under the assumption of local thermal equilibrium (LTE) and a toy non-LTE model for vibrational excitation of selected bands. We show that mixing ratios for individual bands can be retrieved with sufficient precision to allow the vibrational population distributions of the forward models to be reconstructed. A simple fit for the Boltzmann distribution in the LTE case shows that the vibrational temperature is recoverable in this manner. For high resolution, cross-correlation applications, we apply the individual vibrational band analysis to an IRD spectrum of WASP-33b, applying an ‘un-peeling’ technique. Individual detection significances for the two strongest bands are shown to be in line with Boltzmann distributed vibrational state populations consistent with the effective temperature of the WASP-33b atmosphere reported previously. We show the viability of this approach for analysing the individual vibrational state populations behind observed and simulated spectra including reconstructing state population distributions.

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S. Wright, S. Nugroho, M. Brogi, et. al.
Fri, 19 May 23
14/46

Comments: Submitted for publication in AJ

Multifrequency analysis of the radio emission from a post-merger galaxy CGCG 292-057 [GA]

http://arxiv.org/abs/2305.10576


Galaxies exhibiting a specific large-scale extended radio emission, such as X-shaped radio galaxies, belong to a rare class of winged radio galaxies. The morphological evolution of these radio sources is explained using several theoretical models, including galaxy mergers. However, such a direct link between a perturbed radio morphology and a galaxy merger remains observationally sparse. Here we investigate a unique radio galaxy J1159+5820, whose host CGCG 292-057 displays the optical signature of a post-merger system with a distinct tidal tail feature, and an X-shaped radio morphology accompanied by an additional pair of inner lobes. We observed the target on a wide range of radio frequencies ranging from 147 MHz to 4959 MHz, using dedicated GMRT and VLA observations, and supplemented it with publicly available survey data for broadband radio analysis. Particle injection models were fitted to radio spectra of lobes and different parts of the wings. Spectral ageing analysis performed on the lobes and the wings favors a fast jet realignment model with a reorientation timescale of a few million years. We present our results and discuss the possible mechanisms for the formation of the radio morphology.

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A. Misra, M. Jamrozy and M. Weżgowiec
Fri, 19 May 23
15/46

Comments: 13 pages, 9 figures, Accepted for publication in MNRAS

The effect of environment on the properties of the most massive galaxies at $0.5<z<2.5$ in the cosmos-dash field [GA]

http://arxiv.org/abs/2305.10677


How the environment influences the most massive galaxies is still unclear. To explore the environmental effects on morphology and star formation in the most massive galaxies at high redshift, we select galaxies with stellar mass $\log(M_{\star}/M_{\odot})>11$ at $0.5<z<2.5$ in the COSMOS-DASH field, which is the largest field with near-infrared photometrical observations using HST/WFC3 to date. Combining with the newly published COSMOS2020 catalog, we estimate the localized galaxy overdensity using a density estimator within the Bayesian probability framework. With the overdensity map, no significant environmental dependence is found in the distributions of S\'{e}rsic index and effective radius. When we consider the star formation state, galaxies in lower density are found to have higher median specific star formation rate (sSFR) at $0.5<z<1.5$. But for star-forming galaxies only, sSFR is independent of the environment within the whole redshift range, indicating that the primary effect of the environment might be to control the quiescent fraction. Based on these observations, the possible environmental quenching process for these massive galaxies might be mergers.

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J. Song, G. Fang, Y. Gu, et. al.
Fri, 19 May 23
16/46

Comments: 13 pages, 7 figures, To be published in ApJ

Satellite Optical Brightness [IMA]

http://arxiv.org/abs/2305.11123


The apparent brightness of satellites is calculated as a function of satellite position as seen by a ground-based observer in darkness. Both direct illumination of the satellite by the sun as well as indirect illumination due to reflection from the Earth are included. The reflecting properties of each satellite component and of the Earth must first be estimated (the Bidirectional Reflectance Distribution Function, BRDF). Integrating over all scattering surfaces leads to the angular pattern of the flux reflected from the satellite. Finally, the apparent brightness of the satellite as seen by an observer at a given location is calculated as a function of satellite position. We validate our calculations by comparing to observations of selected Starlink satellites and show significant improvement on previous satellite brightness models. With multiple observations of a satellite at various solar angles and with minimal assumptions regarding the satellite, BRDF model coefficients for each satellite component can be accurately inferred, obviating the need to import direct BRDF lab measurements. This widens the effectiveness of this model approach to virtually all satellites. This work finds application in satellite design and operations, and in planning observatory data acquisition and analysis. Similar methodology for predicting satellite brightness has already informed mitigation strategies for next generation Starlink satellites.

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F. Fankhauser, J. Tyson and J. Askari
Fri, 19 May 23
17/46

Comments: 14 pages, 12 figures

Temporal and Latitudinal Variation in Penumbra-Umbra Ratios of the Sunspots: Analyses of RGO, Kodaikanal and Debrecen Databases [SSA]

http://arxiv.org/abs/2305.10757


We study the latitudinal distribution and temporal evolution of the sunspot penumbra-umbra ratio (q) for the even and odd Solar Cycles 12-24 of RGO sunspot groups, SC21-SC24 of Debrecen sunspot groups and Kodaikanal sunspot dataset for SC16-SC24. We find that RGO even (odd) Cycles have q-values 5.20 (4.75), Kodaikanal even (odd) cycles have q-values 5.27 (5.43), and Debrecen cycles has q-value 5.74 on the average. We also show that q is at lowest around the Equator of the Sun and increases towards higher latitudes having maximum values at about 10-25 degrees. This is understandable, because smaller sunspots and groups locate nearer to Equator and have smaller q-values than larger sunspots and groups, which maximize at about 10-20 degrees at both hemispheres. The error limits are very wide and thus the confidence of this result is somewhat vague. For Debrecen dataset we find a deep valley in the temporal q-values before the middle of the cycle. We show that this exists simultaneously with the Gnevyshev gap (GG) in the graph of the total and umbral areas of the large sunspot groups. Other databases do not show GG in their q-graphs, although GG exists in their temporal total area and umbral area.

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T. Juhani
Fri, 19 May 23
18/46

Comments: 17 pages, 15 figures

What boost galaxy mergers in two massive galaxy protoclusters at z = 2.24 [GA]

http://arxiv.org/abs/2305.10932


Characterizing the structural properties of galaxies in high-redshift protoclusters is key to our understanding of the environmental effects on galaxy evolution in the early stages of galaxy and structure formation. In this study, we assess the structural properties of 85 and 87 Halpha emission-line candidates (HAEs) in the densest regions of two massive protoclusters, BOSS1244 and BOSS1542, respectively, using HST H-band imaging data. Our results show a true pair fraction of 22+-5 (33+-6) percent in BOSS1244 (BOSS1542), which yields a merger rate of 0.41+-0.09 (0.52+-0.04) per Gyr for massive HAEs with log (M_/M_sun) > 10.3. This rate is 1.8 (2.8) times higher than that of the general fields at the same epoch. Our sample of HAEs exhibits half-light radii and Sersic indices that cover a broader range than field star-forming galaxies. Additionally, about 15 percent of the HAEs are as compact as the most massive (log(M_/M_sun) > 11) spheroid-dominated population. These results suggest that the high galaxy density and cold dynamical state (i.e., velocity dispersion of <400 km/s) are key factors that drive galaxy mergers and promote structural evolution in the two protoclusters. Our findings also indicate that both the local environment (on group scales) and the global environment play essential roles in shaping galaxy morphologies in protoclusters. This is evident in the systematic differences observed in the structural properties of galaxies between BOSS1244 and BOSS1542.

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S. Liu, X. Zheng, D. Shi, et. al.
Fri, 19 May 23
19/46

Comments: 20 pages, 5 figures, 1 table. Accepted for publication in MNRAS

A transient ultraviolet outflow in the short-period X-ray binary UW CrB [HEAP]

http://arxiv.org/abs/2305.10793


Accreting low mass X-ray binaries (LMXBs) are capable of launching powerful outflows such as accretion disc winds. In disc winds, vast amounts of material can be carried away, potentially greatly impacting the binary and its environment. Previous studies have uncovered signatures of disc winds in the X-ray, optical, near-infrared, and recently even the UV band, predominantly in LMXBs with large discs ($P_{orb}{\geq}20$ hrs). Here, we present the discovery of transient UV outflow features in UW CrB, a high-inclination ($i{\geq}77$\deg) neutron star LMXB with an orbital period of only $P_{orb}{\approx}111$ min. We present P-Cygni profiles detected for Si iv 1400\r{A} and tentatively for N v 1240\r{A} in one 15 min exposure, which is the only exposure covering orbital phase $\phi{\approx}0.7{-}0.8$, with a velocity of ${\approx}1500$ km/s. We show that due to the presence of black body emission from the neutron star surface and/or boundary layer, a thermal disc wind can be driven despite the short $P_{orb}$, but explore alternative scenarios as well. The discovery that thermal disc winds may occur in NS-LMXBs with $P_{orb}$ as small as ${\approx}111$ min, and can potentially be transient on time scales as short as ${\approx}15$ min, warrants further observational and theoretical work.

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S. Fijma, N. Segura, N. Degenaar, et. al.
Fri, 19 May 23
20/46

Comments: 5 pages, 5 figures. Submitted to MNRAS

Searching for Intragroup Light in Deep U-band Imaging of the COSMOS Field [GA]

http://arxiv.org/abs/2305.10516


We present the results of deep, ground based U-band imaging with the Large Binocular Telescope of the Cosmic Evolution Survey (COSMOS) field as part of the near-UV imaging program, UVCANDELS. We utilize a seeing sorted stacking method along with night-to-night relative transparency corrections to create optimal depth and optimal resolution mosaics in the U-band, which are capable of reaching point source magnitudes of AB 26.5 mag at 3 sigma. These ground based mosaics bridge the wavelength gap between the HST WFC3 F27W and ACS F435W images and are necessary to understand galaxy assembly in the last 9-10 Gyr. We use the depth of these mosaics to search for the presence of U-band intragroup light (IGrL) beyond the local Universe. Regardless of how groups are scaled and stacked, we do not detect any U-band IGrL to unprecedented U-band depths of 29.1-29.6 mag/arcsec2, which corresponds to an IGrL fraction of less than 1% of the total group light. This stringent upper limit suggests that IGrL does not contribute significantly to the Extragalactic Background Light at short wavelengths. Furthermore, the lack of UV IGrL observed in these stacks suggests that the atomic gas observed in the intragroup medium (IGrM) is likely not dense enough to trigger star formation on large scales. Future studies may detect IGrL by creating similar stacks at longer wavelengths or by pre-selecting groups which are older and/or more dynamically evolved similar to past IGrL observations of compact groups and loose groups with signs of gravitational interactions.

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T. McCabe, C. Redshaw, L. Otteson, et. al.
Fri, 19 May 23
21/46

Comments: Accepted to PASP

The precursor of GRB211211A: a tide-induced giant quake? [HEAP]

http://arxiv.org/abs/2305.10682


The equilibrium configuration of a solid strange star in the final inspiral phase with another compact object is generally discussed, and the starquake-related issue is revisited, for a special purpose to understand the precursor emission of binary compact star merger events (e.g., that of GRB211211A). As the binary system inspirals inward due to gravitational wave radiation, the ellipticity of the solid strangeon star increases due to the growing tidal field of its compact companion. Elastic energy is hence accumulated during the inspiral stage which might trigger a starquake before the merger when exceeds a critical value. The energy released during such starquakes is calculated and compared to the precursor observation of GRB211211A. The result shows that the energy might be insufficient for binary strangeon-star case unless the entire solid strangeon star shatters, and hence favors a black hole-strangeon star scenario for GRB211211A. The timescale of the precursor as well as the frequency of the observed quasi-periodic-oscillation have also been discussed in the starquake model.

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E. Zhou, Y. Gao, Y. Zhou, et. al.
Fri, 19 May 23
22/46

Comments: 10 pages, 7 figures; comments are welcome!

The warm inflation story [CL]

http://arxiv.org/abs/2305.10879


Warm inflation has normalized two ideas in cosmology, that in the early universe the initial primordial density perturbations generally could be of classical rather than quantum origin and that during inflation, particle production from interactions amongst quantum field, and its backreaction effects, can occur concurrent with inflationary expansion. When we first introduced these ideas, both were met with resistance, but today they are widely accepted as possibilities with many models and applications based on them, which is an indication of the widespread influence of warm inflation. Open quantum field theory, which has been utilized in studies of warm inflation, is by now a relevant subject in cosmology, in part due to this early work. In this review I first discuss the basic warm inflation dynamics. I then outline how to compute warm inflation dynamics from first principles quantum field theory (QFT) and in particular how a dissipative term arises. Warm inflation models can have an inflaton mass bigger than the Hubble scale and the inflaton field excursion can remain sub-Planckian, thus overcoming the most prohibitive problems of inflation model building. I discuss the early period of my work in developing warm inflation that helped me arrive at these important features of its dynamics. Inflationary cosmology today is immersed in hypothetical models, which by now are acting as a diversion from reaching any endgame in this field. I discuss better ways to approach model selection and give necessary requirements for a well constrained and predictive inflation model. I point out a few warm inflation models that could be developed to this extent. I discuss how at this stage more progress would be made in this subject by taking a broader view on the possible early universe solutions that include not just inflation but the diverse range of options.

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A. Berera
Fri, 19 May 23
23/46

Comments: N/A

Direct mapping of tidal deformability to the iso-scalar and iso-vector nuclear matter parameters [CL]

http://arxiv.org/abs/2305.11007


Background: The equations of state (EoSs) which determine the properties of neutron stars (NSs) are often characterized by the iso-scalar and iso-vector nuclear matter parameters (NMPs). Recent attempts to relate the radius and tidal deformability of a NS to the individual NMPs have been inconclusive. These properties display strong correlations with the pressure of NS matter which depends on several NMPs. The knowledge of minimal NMPs that determine the NS properties will be necessary to address any connection between NS properties (e.g., tidal deformability) and that of finite nuclei.
Purpose: To identify the important NMPs required to describe the tidal deformability of neutron star for astrophysically relevant range of their gravitational masses (1.2 — 1.8 M$\odot$) as encountered in the binary neutron star merger events.
Method: We construct a large set of EoSs using four iso-scalar and five iso-vector NMPs. These EOSs are employed to perform a systematic analysis to isolate the NMPs that predominantly determine the tidal deformability, over a wide range of NS mass. The tidal deformability is then directly mapped to these NMPs.
Results: The tidal deformability of the NS with mass 1.2-1.8 M$
\odot$ can be determined within 10$\%$ directly in terms of four nuclear matter parameters, namely, the incompressibility $K_0$ and skewness $Q_0$ of symmetric nuclear matter, and the slope $L_0$ and curvature parameter $K_{\rm sym,0}$ of symmetry energy.
Conclusion: A function that quickly estimates the value of tidal deformability in terms of minimal nuclear matter parameters is developed. Our method can also be extended to other NS observables.

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S. Imam, A. Mukherjee, B. Agrawal, et. al.
Fri, 19 May 23
24/46

Comments: 5 pages, 5 figures

Up-down binaries are unstable and we want to know [CL]

http://arxiv.org/abs/2305.10776


The relativistic spin-precession equations for black-hole binaries have four different equilibrium solutions that correspond to systems where the two individual black hole spins are either aligned or anti-aligned with the orbital angular momentum. Surprisingly, it was demonstrated that only three of these equilibrium solutions are stable. Binary systems in the up-down configuration, where the spin of the heavier (lighter) black hole is co- (counter-) aligned with the orbital angular momentum, might be unstable to small perturbations of the spin directions. After the onset of the up-down instability, that occurs after a specific critical orbital separation $r_\mathrm{UD+}$, the binary becomes unstable to spin precession leading to large misalignment of the spins. In this work, we present a Bayesian procedure based on the Savage-Dickey density ratio to test the up-down origin of gravitational-wave events. We apply this procedure to look for promising candidates among the events detected so far during the first three observing runs performed by LIGO/Virgo.

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V. Renzis
Fri, 19 May 23
25/46

Comments: Contribution to the 2023 Gravitation session of the 57th Rencontres de Moriond

PPDONet: Deep Operator Networks for Fast Prediction of Steady-State Solutions in Disk-Planet Systems [EPA]

http://arxiv.org/abs/2305.11111


We develop a tool, which we name Protoplanetary Disk Operator Network (PPDONet), that can predict the solution of disk-planet interactions in protoplanetary disks in real-time. We base our tool on Deep Operator Networks (DeepONets), a class of neural networks capable of learning non-linear operators to represent deterministic and stochastic differential equations. With PPDONet we map three scalar parameters in a disk-planet system — the Shakura \& Sunyaev viscosity $\alpha$, the disk aspect ratio $h_\mathrm{0}$, and the planet-star mass ratio $q$ — to steady-state solutions of the disk surface density, radial velocity, and azimuthal velocity. We demonstrate the accuracy of the PPDONet solutions using a comprehensive set of tests. Our tool is able to predict the outcome of disk-planet interaction for one system in less than a second on a laptop. A public implementation of PPDONet is available at \url{https://github.com/smao-astro/PPDONet}.

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S. Mao, R. Dong, L. Lu, et. al.
Fri, 19 May 23
26/46

Comments: 10 pages, 6 figures, 2 tables; ApJL accepted

Relativistic drag forces on black holes from scalar dark matter clouds of all sizes [CL]

http://arxiv.org/abs/2305.10492


We use numerical simulations of scalar field dark matter evolving on a moving black hole background to confirm the regime of validity of (semi-)analytic expressions derived from first principles for both dynamical friction and momentum accretion in the relativistic regime. We cover both small and large clouds (relative to the de Broglie wavelength of the scalars), and light and heavy particle masses (relative to the BH size). In the case of a small dark matter cloud, the effect of accretion is a non-negligible contribution to the total force on the black hole, even for small scalar masses. We confirm that this momentum accretion transitions between two regimes (wave- and particle-like) and we identify the mass of the scalar at which the transition between regimes occurs.

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D. Traykova, R. Vicente, K. Clough, et. al.
Fri, 19 May 23
27/46

Comments: 11 pages, 5 figures. Comments welcome!

A Multi-Wavelength Investigation of Dust and Stellar Mass Distributions in Galaxies: Insights from High-Resolution JWST Imaging [GA]

http://arxiv.org/abs/2305.10944


We study the morphological properties of mid-infrared selected galaxies at $1.0<z<1.7$ in the SMACS J0723.3-7327 cluster field, to investigate the mechanisms of galaxy mass assembly and structural formation at cosmic noon. We develop a new algorithm to decompose the dust and stellar components of individual galaxies by utilizing high-resolution images in the MIRI F770W and NIRCam F200W bands. Our analyses reveal that most galaxies in the stellar mass range ${\rm 10^{9.5}<M_/M_\odot<10^{10.5}}$ have dust cores relatively compact compared to their stellar cores, whereas the most massive ($\rm{M_ \sim 10^{10.9}\,M_\odot}$) galaxy in our sample displays a comparably compact stellar core as to dust. The observed compactness of the dust component is potentially attributed to the presence of a (rapidly growing) massive bulge, in some cases associated with elevated star formation. Expanding the sample size through a joint analysis of multiple Cycle~1 deep-imaging programs can help to confirm the inferred picture. Our pilot study highlights that MIRI offers an efficient approach to studying the structural formation of galaxies from cosmic noon to the modern universe.

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Z. Liu, T. Morishita and T. Kodama
Fri, 19 May 23
28/46

Comments: 19 pages, 8 figures, submitted to ApJ

Automated detection and analysis of coronal active region structures across Solar Cycle 24 [SSA]

http://arxiv.org/abs/2305.11066


Observations from the NASA Solar Dynamic Observatory Atmospheric Imaging Assembly were employed to investigate targeted physical properties of coronal active region structures across the entirety of Solar Cycle 24 (dates). This is the largest consistent study to date which analyses emergent trends in structural width, location, and occurrence rate by performing an automatic and long-term examination of observable coronal limb features within equatorial active region belts across four extreme ultraviolet wavelengths (171, 193, 211, and 304 angstroms). This has resulted in over thirty thousand observed coronal structures and hence allows for the production of spatial and temporal distributions focused upon the rise, peak and decay activity phases of Solar Cycle 24. Employing a self-organized-criticality approach as a descriptor of coronal structure formation, power law slopes of structural widths versus frequency are determined, ranging from -1.6 to -3.3 with variations of up to 0.7 found between differing periods of the solar cycle, compared to a predicted Fractal Diffusive Self Organized Criticality (FD-SOC) value of -1.5. The North-South hemispheric asymmetry of these structures was also examined with the northern hemisphere exhibiting activity that is peaking earlier and decaying slower than the southern hemisphere, with a characteristic “butterfly” pattern of coronal structures detected. This represents the first survey of coronal structures performed across an entire solar cycle, demonstrating new techniques available to examine the composition of the corona by latitude in varying wavelengths at selected altitudes.

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D. Gass and R. Walsh
Fri, 19 May 23
29/46

Comments: 16 pages, 10 figures. Preprint copy

Lepto-hadronic interpretation of 2021 RS Ophiuchi nova outburst [HEAP]

http://arxiv.org/abs/2305.10735


Very high energy (VHE; 100 GeV $<$ E $\leq$ 100 TeV) and high energy (HE; 100 MeV $<$ E $\leq$ 100 GeV) gamma-rays were observed from the symbiotic recurrent nova RS Ophiuchi (RS Oph) during its outburst in August 2021, by various observatories such as High Energy Stereoscopic System (H.E.S.S.), Major Atmospheric Gamma Imaging Cherenkov (MAGIC), and {\it Fermi}-Large Area Telescope (LAT). The models explored so far tend to favor a hadronic scenario of particle acceleration over an alternative leptonic scenario. This paper explores a time-dependent lepto-hadronic scenario to explain the emission from the RS Oph source region. We have used simultaneous low frequency radio data observed by various observatories, along with the data provided by H.E.S.S., MAGIC, and \textit{Fermi}-LAT, to explain the multi-wavelength (MWL) spectral energy distributions (SEDs) corresponding to 4 days after the outburst. Our results show that a lepto-hadronic interpretation of the source not only explains the observed HE-VHE gamma-ray data but the corresponding model synchrotron component is also consistent with the first 4 days of low radio frequency data, indicating the presence of non-thermal radio emission at the initial stage of nova outburst. We have also calculated the expected neutrino flux from the source region and discussed the possibility of detecting neutrinos.

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A. Sarkar, N. J., N. Roy, et. al.
Fri, 19 May 23
30/46

Comments: 18 pages, 5 figures, 2 tables; accepted for publication in The Astrophysical Journal (ApJ)

Parameterized Parity Violation in Gravitational Wave Propagation [CL]

http://arxiv.org/abs/2305.10478


Gravitational parity violation arises in a variety of theories beyond general relativity. Gravitational waves in such theories have their propagation altered, leading to birefringence effects in both the amplitude and speed of the wave. In this work, we introduce a generalized, theory-motivated parametrization scheme to study parity violation in gravitational wave propagation. This parametrization maps to parity-violating gravity theories in a straightforward way. We find that the amplitude and velocity birefringence effects scale with an effective distance measure that depends on how the dispersion relation is modified. Furthermore, we show that this generic parametrization can be mapped to the parametrized-post-Einsteinian (ppE) formalism with convenient applications to gravitational wave observations and model-agnostic tests of general relativity. We derive a mapping to the standard ppE waveform of the gravitational wave response function, and also find a ppE waveform mapping at the level of the polarization modes, $h_+$ and $h_\times$. Finally, we show how existing constraints in the literature translate to bounds on our new parity-violating parameters and discuss avenues for future analysis.

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L. Jenks, L. Choi, M. Lagos, et. al.
Fri, 19 May 23
31/46

Comments: 19 pages

Optical Alignment Method for the PRIME Telescope [IMA]

http://arxiv.org/abs/2305.10796


We describe the optical alignment method for the Prime-focus Infrared Microlensing Experiment (PRIME) telescope which is a prime-focus near-infrared (NIR) telescope with a wide field of view for the microlensing planet survey toward the Galactic center that is the major task for the PRIME project. There are three steps for the optical alignment: preliminary alignment by a laser tracker, fine alignment by intra- and extra-focal (IFEF) image analysis technique, and complementary and fine alignment by the Hartmann test. We demonstrated that the first two steps work well by the test conducted in the laboratory in Japan. The telescope was installed at the Sutherland Observatory of South African Astronomical Observatory in August, 2022. At the final stage of the installation, we demonstrated that the third method works well and the optical system satisfies the operational requirement.

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H. Yama, D. Suzuki, S. Miyazaki, et. al.
Fri, 19 May 23
32/46

Comments: 16 pages, 10 figures, and 6 tables. Accept for publication in Journal of Astronomical Instrumentation

Fast particle acceleration in 3D hybrid simulations of quasi-perpendicular shocks [HEAP]

http://arxiv.org/abs/2305.10511


We use hybrid (kinetic ions — fluid electrons) kinetic simulations to investigate particle acceleration and magnetic field amplification at non-relativistic, weakly magnetized, quasi-perpendicular shocks. Unlike 2D simulations, 3D runs show that protons develop a non-thermal tail spontaneously (i.e., from the thermal bath and without pre-existing magnetic turbulence). They are rapidly accelerated via shock drift acceleration up to a maximum energy determined by their escape upstream.

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L. Orusa and D. Caprioli
Fri, 19 May 23
33/46

Comments: 6 pages, 4 figures. Submitted to PRL

Gravitational Machines [CL]

http://arxiv.org/abs/2305.10470


A gravitational machine is defined as an arrangement of gravitating masses from which useful energy can be extracted. It is shown that such machines may exist if the masses are of normal astronomical size. A simple example of a gravitational machine, consisting of a double star with smaller masses orbiting around it, is described. It is shown that an efficient gravitational machine will also be an emitter of gravitational radiation. The emitted radiation sets a limit on the possible performance of gravitational machines, and also provides us with a possible means for detecting such machines if they exist.

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F. Dyson
Fri, 19 May 23
34/46

Comments: 4 pages, one figure

The LHAASO PeVatron bright sky: what we learned [HEAP]

http://arxiv.org/abs/2305.10526


The recent detection of 12 gamma-ray Galactic sources well above E > 100 TeV by the LHAASO observatory has been a breakthrough in the context of Cosmic Ray (CR) origin search. Although most of these sources are unidentified, they are often spatially correlated with leptonic accelerators, like pulsar and pulsar wind nebulae (PWNe). This dramatically affects the paradigm for which a gamma-ray detection at E > 100 TeV implies the presence of a hadronic accelerator of PeV particles (PeVatron). Moreover, the LHAASO results support the idea that sources other than the standard candidates, Supernova Remnants, can accelerate Galactic CRs. In this context, the good angular resolution of future Cherenkov telescopes, such as the ASTRI Mini-Array and CTA, and the higher sensitivity of future neutrino detectors, such as KM3NeT and IceCube-Gen2, will be of crucial importance. In this brief review, we want to summarize the efforts done up to now, from both theoretical and experimental points of view, to fully understand the LHAASO results in the context of the CR acceleration issue.

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M. Cardillo and A. Giuliani
Fri, 19 May 23
35/46

Comments: Accepted for the special Issue “High Energy Multi-Messenger Astrophysics: Latest Research and Reviews” of the journal “Applied Science”

Time-independent Simulations of Steady-State Accretion with Nuclear Burning [HEAP]

http://arxiv.org/abs/2305.10627


We construct a new formulation that allows efficient exploration of steady-state accretion processes onto compact objects. Accretion onto compact objects is a common scenario in astronomy. These systems serve as laboratories to probe the nuclear burning of the accreted matter. Conventional stellar evolution codes have been developed to simulate in detail the nuclear reactions on the compact objects. In order to follow the case of steady burning, however, using these codes can be very expensive as they are designed to follow a time-dependent problem. Here we introduce our new code $\textsc{StarShot}$, which resolves the structure of the compact objects for the case of stable thermonuclear burning, and is able to follow all nuclear species using an adaptive nuclear reaction network and adaptive zoning. Compared to dynamical codes, the governing equations can be reduced to time-independent forms under the assumption of steady-state accretion. We show an application to accreting low mass X-ray binaries (LMXBs) with accretion onto a neutron-star as compact object. The computational efficiency of $\textsc{StarShot}$ allows to to explore the parameter space for stable burning regimes, and can be used to generate initial conditions for time-dependent evolution models.

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K. Tse, A. Heger, R. Hirai, et. al.
Fri, 19 May 23
36/46

Comments: 11 pages, 4 figures

Multiple Peaks and a Long Precursor in the Type IIn Supernova 2021qqp: An Energetic Explosion in a Complex Circumsteller Environment [HEAP]

http://arxiv.org/abs/2305.11168


We present detailed optical photometry and spectroscopy of the Type IIn supernova (SN) 2021qqp. Its unusual light curve is marked by a long gradual brightening (i.e., precursor) for about 300 days, a rapid increase in brightness for about 60 days, and then a sharp increase of about 1.6 mag in only a few days to a first peak of $M_r\approx -19.5$ mag. The light curve then turns over and declines rapidly, until it re-brightens to a second distinct and sharp peak with $M_r\approx -17.3$ mag centered at about 335 days after the first peak. The spectra are dominated by Balmer-series lines with a complex morphology that includes a narrow component with a width of $\approx 1300$ km s$^{-1}$ (first peak) and $\approx 2500$ km s$^{-1}$ (second peak) that we associate with the circumstellar medium (CSM), and a P Cygni component with an absorption velocity of $\approx 8500$ km s$^{-1}$ (first peak) and $\approx 5600$ km s$^{-1}$ (second peak) that we associate with the SN-CSM interaction shell. Using the bolometric light curve and velocity evolution, we construct an analytical model to extract the CSM profile and SN properties. We find two significant mass-loss episodes with peak mass loss rates of $\approx 10$ M$\odot$ yr$^{-1}$ and $\approx 5$ M$\odot$ yr$^{-1}$ about 0.8 and 2 years before explosion, and a total CSM mass of $\approx 2-4\,M_\odot$. We show that the most recent mass-loss episode can explain the precursor for the year preceding the explosion. The SN ejecta mass is constrained to be $M_{\rm SN}\approx 5-30\,M_\odot$ for an explosion energy of $E_{\rm SN}\approx (3-10)\times10^{51}\,{\rm erg}$. We discuss eruptive massive stars (luminous blue variable, pulsational pair instability) and an extreme stellar merger with a compact object as possible progenitor channels for generating the energetic explosion in the complex CSM environment.

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D. Hiramatsu, T. Matsumoto, E. Berger, et. al.
Fri, 19 May 23
37/46

Comments: 20 pages, 7 figures, submitted to ApJ

Afterglow polarizations in a stratified medium with effect of the equal arrival time surface [HEAP]

http://arxiv.org/abs/2305.10590


The environment of gamma-ray burst (GRB) has an important influence on the evolution of jet dynamics and of its afterglow. Here we investigate the afterglow polarizations in a stratified medium with the equal arrival time surface (EATS) effect. Polarizations of multi-band afterglows are predicted. The effects of the parameters of the stratified medium on the afterglow polarizations are also investigated. We found the influences of the EATS effect on the afterglow polarizations become important for off-axis detections and PD bumps move to later times with the EATS effect. Even the magnetic field configurations, jet structure and observational angles are fixed, polarization properties of the jet emission could still evolve. Here, we assume a large-scale ordered magnetic field in the reverse-shock region and a two-dimensional random field in the forward-shock region. Then PD evolution is mainly determined by the evolution of $f_{32}$ parameter (the flux ratio between the reverse-shock region and forward-shock region) at early stage and by the evolution of the bulk Lorentz factor $\gamma$ at late stage. Through the influences on the $f_{32}$ or $\gamma$, the observational energy band, observational angles, and the parameters of the stratified medium will finally affect the afterglow polarizations.

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M. Lan, X. Wu and Z. Dai
Fri, 19 May 23
38/46

Comments: 16 pages, 8 figures, accepted by ApJ

The first X-ray look at SMSS J114447.77-430859.3: the most luminous quasar in the last 9 Gyr [HEAP]

http://arxiv.org/abs/2305.10745


SMSS\,J114447.77-430859.3 ($z=0.83$) has been identified in the SkyMapper Southern Survey as the most luminous quasar in the last $\sim 9\,\rm Gyr$. In this paper, we report on the eROSITA/Spectrum-Roentgen-Gamma (SRG) observations of the source from the eROSITA All Sky Survey, along with presenting results from recent monitoring performed using Swift, XMM-Newton, and NuSTAR. The source shows a clear variability by factors of $\sim 10$ and $\sim 2.7$ over timescales of a year and of a few days, respectively. When fit with an absorbed power law plus high-energy cutoff, the X-ray spectra reveal a $\Gamma=2.2 \pm 0.2$ and $E_{\rm cut}=23^{+26}{-5}\,\rm keV$. Assuming Comptonisation, we estimate a coronal optical depth and electron temperature of $\tau=2.5-5.3\, (5.2-8)$ and $kT=8-18\, (7.5-14)\,\rm keV$, respectively, for a slab (spherical) geometry. The broadband SED is successfully modelled by assuming either a standard accretion disc illuminated by a central X-ray source, or a thin disc with a slim disc emissivity profile. The former model results in a black hole mass estimate of the order of $10^{10}\,M\odot$, slightly higher than prior optical estimates; meanwhile, the latter model suggests a lower mass. Both models suggest sub-Eddington accretion when assuming a spinning black hole, and a compact ($\sim 10\,r_{\rm g}$) X-ray corona. The measured intrinsic column density and the Eddington ratio strongly suggest the presence of an outflow driven by radiation pressure. This is also supported by variation of absorption by an order of magnitude over the period of $\sim 900\,\rm days$.

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E. Kammoun, Z. Igo, J. Miller, et. al.
Fri, 19 May 23
39/46

Comments: Accepted for publication in MNRAS

HI Self-absorption toward the Cygnus X North: From Atomic Filament to Molecular Filament [GA]

http://arxiv.org/abs/2305.10795


Using the HI self-absorption data from the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we perform a study of the cold atomic gas in the Cygnus-X North region. The most remarkable HI cloud is characterized by a filamentary structure, associated in space and in velocity with the principle molecular filament in the Cygnus-X North region. We investigate the transition from the atomic filament to the molecular filament. We find that the HII regions Cygnus OB2 and G081.920+00.138 play a critical role in compressing and shaping the atomic Cygnus-X North filament, where the molecular filament subsequently forms. The cold HI in the DR21 filament has a much larger column density (N(HI) $\sim$ 1 $\times$ 10$^{20}$ cm$^{-2}$) than the theoretical value of the residual atomic gas ($\sim$ 1 $\times$ 10$^{19}$ cm$^{-2}$), suggesting that the HI-to-H$_2$ transition is still in progress. The timescale of the HI-to-H$_2$ transition is estimated to be 3 $\times$ 10$^{5}$ yr, which approximates the ages of massive protostars in the Cygnus-X North region. This implies that the formation of molecular clouds and massive stars may occur almost simultaneously in the DR21 filament, in accord with a picture of rapid and dynamic cloud evolution.

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C. Li, K. Qiu, D. Li, et. al.
Fri, 19 May 23
40/46

Comments: 10 pages, 7 figures

Reconstruction of asteroid spin states from Gaia DR3 photometry [EPA]

http://arxiv.org/abs/2305.10798


Gaia Data Release 3 contains accurate photometric observations of more than 150,000 asteroids covering a time interval of 34 months. With a total of about 3,000,000 measurements, a typical number of observations per asteroid ranges from a few to several tens. We aimed to reconstruct the spin states and shapes of asteroids from this dataset. We computed the viewing and illumination geometry for each individual observation and used the light curve inversion method to find the best-fit asteroid model, which was parameterized by the sidereal rotation period, the spin axis direction, and a low-resolution convex shape. To find the best-fit model, we ran the inversion for tens of thousands of trial periods on interval 2-10,000 h, with tens of initial pole directions. To find the correct rotation period, we also used a triaxial ellipsoid model for the shape approximation. In most cases the number of data points was insufficient to uniquely determine the rotation period. However, for about 8600 asteroids we were able to determine the spin state uniquely together with a low-resolution convex shape model. This large sample of new asteroid models enables us to study the spin distribution in the asteroid population. The distribution of spins confirms previous findings that (i) small asteroids have poles clustered toward ecliptic poles, likely because of the YORP-induced spin evolution, (ii) asteroid migration due to the Yarkovsky effect depends on the spin orientation, and (iii) members of asteroid families have the sense of rotation correlated with their proper semimajor axis: over the age of the family, orbits of prograde rotators evolved, due to the Yarkovsky effect, to larger semimajor axes, while those of retrograde rotators drifted in the opposite direction.

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J. Durech and J. Hanus
Fri, 19 May 23
41/46

Comments: N/A

Production of $p$-nuclei from $r$-process seeds: the $νr$-process [HEAP]

http://arxiv.org/abs/2305.11050


We present a new nucleosynthesis process that may take place on neutron-rich ejecta experiencing an intensive neutrino flux. The nucleosynthesis proceeds similarly to the standard $r$-process, a sequence of neutron-captures and beta-decays, however with charged-current neutrino absorption reactions on nuclei operating much faster than beta-decays. Once neutron capture reactions freeze-out the produced $r$-process neutron-rich nuclei undergo a fast conversion of neutrons into protons and are pushed even beyond the $\beta$-stability line producing the neutron-deficient $p$-nuclei. This scenario, which we denote as the $\nu r$-process, provides an alternative channel for the production of $p$-nuclei and the short-lived nucleus $^{92}$Nb. We discuss the necessary conditions posed on the astrophysical site for the $\nu r$-process to be realized in nature. While these conditions are not fulfilled by current neutrino-hydrodynamic models of $r$-process sites, future models, including more complex physics and a larger variety of outflow conditions, may achieve the necessary conditions in some regions of the ejecta.

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Z. Xiong, G. Martínez-Pinedo, O. Just, et. al.
Fri, 19 May 23
42/46

Comments: 8 pages, 5 figures, submitted to PRL

Dissecting the RELICS cluster SPT-CLJ0615-5746 through the intracluster light: confirmation of the multiple merging state of the cluster formation [GA]

http://arxiv.org/abs/2305.10860


The intracluster light (ICL) fraction, measured at certain specific wavelengths, has been shown to provide a good marker for determining the dynamical stage of galaxy clusters, i.e., merging versus relaxed, for small to intermediate redshifts. Here, we apply it for the first time to a high-redshift system, SPT-CLJ0615-5746 at z=0.97, using its RELICS (Reionization Lensing Cluster Survey) observations in the optical and infrared. We find the ICL fraction signature of merging, with values ranging from 16 to 37%. A careful re-analysis of the X-ray data available for this cluster points to the presence of at least one current merger, and plausibly a second merger. These two results are in contradiction with previous works based on X-ray data, which claimed the relaxed state of SPT-CLJ0615-5746, and confirmed the evidences presented by kinematic analyses. We also found an abnormally high ICL fraction in the rest-frame near ultraviolet wavelengths, which may be attributed to the combination of several phenomena such as an ICL injection during recent mergers of stars with average early-type spectra, the reversed star formation-density relation found at this high redshift in comparison with lower-redshift clusters, and projection effects.

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Y. Jiménez-Teja, R. Dupke, P. Lopes, et. al.
Fri, 19 May 23
43/46

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

Primordial Black Hole Reheating [CL]

http://arxiv.org/abs/2305.10518


Post-inflationary reheating phase is usually said to be solely governed by the decay of coherently oscillating inflaton into radiation. In this submission, we explore a new avenue toward reheating through the evaporation of primordial black holes (PBHs). After the inflation, if PBHs form, depending on its initial mass, abundance, and inflaton coupling with the radiation, we found two physically distinct possibilities of reheating the universe. In one possibility, the thermal bath is solely obtained from the decay of PBHs while inflaton plays the role of dominant energy component in the entire process. In the other possibility, we found that PBHs itself dominate the total energy budget of the Universe during the course of evolution, and then its subsequent evaporation leads to radiation dominated universe. Furthermore, we analyze the impact of both monochromatic and extended PBH mass functions and estimate the detailed parameter ranges for which those distinct reheating histories are realized.

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M. Haque, E. Kpatcha, D. Maity, et. al.
Fri, 19 May 23
44/46

Comments: 17 pages, 9 figures

Peering into the tilted heart of Cyg X-1 with high-precision optical polarimetry [HEAP]

http://arxiv.org/abs/2305.10813


We present the high-precision optical polarimetric observations of black hole X-ray binary Cyg X-1, spanning several cycles of its 5.6 day orbital period. Week-long observations on two telescopes located in opposite hemispheres allowed us to track the evolution of the polarization within one orbital cycle with the highest temporal resolution to date. Using the field stars, we determine the interstellar polarization in the source direction and subsequently its intrinsic polarization. The optical polarization angle is aligned with that in the X-rays as recently obtained with the Imaging X-ray Polarimetry Explorer. Furthermore, it is consistent, within the uncertainties, with the position angle of the radio ejections. We show that the intrinsic PD is variable with the orbital period with the amplitude of $\sim$0.2% and discuss various sites of its production. Assuming the polarization arises from a single Thomson scattering of the primary star radiation by the matter that follows the black hole in its orbital motion, we constrain the inclination of the binary orbit $i>120^\circ$ and its eccentricity $e<0.08$. The asymmetric shape of the orbital profiles of Stokes parameters implies also the asymmetry of the scattering matter distribution about the orbital plane, which may arise from the tilted accretion disk. We compare our data to the polarimetric observations made over 1975-1987 and find good, within $1^\circ$, agreement between the intrinsic polarization angles. On the other hand, the PD decreased by 0.4% over half a century, suggesting the presence of secular changes in the geometry of accreting matter.

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V. Kravtsov, A. Veledina, A. Berdyugin, et. al.
Fri, 19 May 23
45/46

Comments: 12 pages, 18 figures

Equilibrium dynamical models for the Large Magellanic Cloud [GA]

http://arxiv.org/abs/2305.10980


The Large Magellanic Cloud (LMC) has a complex dynamics driven by both internal and external processes. The external forces are due to tidal interactions with the Small Magellanic Cloud and the Milky Way, while internally its dynamics mainly depends on the stellar, gas, and dark matter mass distributions. Despite the overall complexity of the system, very often simple physical models can give us important insights about the main driving factors. Here we focus on the internal forces and attempt to model the proper motions of $\sim10^6$ stars in the LMC as measured by Gaia Data Release 3 with an axisymmetric dynamical model, based on the Jeans equations. We test both cored and cusped spherical Navarro-Frenk-White dark matter halos to fit the LMC gravitational potential. We find that this simple model is very successful at selecting a clean sample of genuine LMC member stars and predicts the geometry and orientation of the LMC with respect to the observer within the constraint of axisymmetry. Our Jeans dynamical models describe well the rotation profile and the velocity dispersion of the LMC stellar disc, however they fail to describe the motions of the LMC bar, which is a non-axisymmetric feature dominating the central region. We plan a triaxial Schwarzschild approach as a next step for the dynamical modelling of the LMC.

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N. Kacharov and M. Cioni
Fri, 19 May 23
46/46

Comments: 6 pages, 4 figures, IAUS379: “Dynamical masses of Local group galaxies” proceeding

Simulating the diversity of shapes of the Lyman-$α$ line [GA]

http://arxiv.org/abs/2305.10047


The Ly$\alpha$ line is a powerful probe of distant galaxies, which contains information about inflowing/outflowing gas through which Ly$\alpha$ photons scatter. To develop our understanding of this probe, we post-process a zoom-in radiation-hydrodynamics simulation of a low-mass ($M_* \sim 10^9 M_\odot$) galaxy to construct 22500 mock spectra in 300 directions from $z = 3$ to 4. Remarkably, we show that one galaxy can reproduce the variety of a large sample of spectroscopically observed Ly$\alpha$ line profiles. While most mock spectra exhibit double-peak profiles with a dominant red peak, their shapes cover a large parameter space in terms of peak velocities, peak separation and flux ratio. This diversity originates from radiative transfer effects at ISM and CGM scales, and depends on galaxy inclination and evolutionary phase. Red-dominated lines preferentially arise in face-on directions during post-starburst outflows and are bright. Conversely, accretion phases usually yield symmetric double peaks in the edge-on direction and are fainter. While resonant scattering effects at $< 0.2\times R_{\rm vir}$ are responsible for the broadening and velocity shift of the red peak, the extended CGM acts as a screen and impacts the observed peak separation. The ability of simulations to reproduce observed Ly$\alpha$ profiles and link their properties with galaxy physical parameters offers new perspectives to use Ly$\alpha$ to constrain the mechanisms that regulate galaxy formation and evolution. Notably, our study implies that deeper Ly$\alpha$ surveys may unveil a new population of blue-dominated lines tracing inflowing gas.

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J. Blaizot, T. Garel, A. Verhamme, et. al.
Thu, 18 May 23
1/67

Comments: Accepted for publication in MNRAS

SP(k) — A hydrodynamical simulation-based model for the impact of baryon physics on the non-linear matter power spectrum [CEA]

http://arxiv.org/abs/2305.09710


Upcoming large-scale structure surveys will measure the matter power spectrum to approximately percent level accuracy with the aim of searching for evidence for new physics beyond the standard model of cosmology. In order to avoid biasing our conclusions, the theoretical predictions need to be at least as accurate as the measurements for a given choice of cosmological parameters. However, recent theoretical work has shown that complex physical processes associated with galaxy formation (particularly energetic feedback processes associated with stars and especially supermassive black holes) can alter the predictions by many times larger than the required accuracy. Here we present $\texttt{SP(k)}$, a model for the effects of baryon physics on the non-linear matter power spectrum based on a new large suite of hydrodynamical simulations. Specifically, the ANTILLES suite consists of 400 simulations spanning a very wide range of the “feedback landscape” and show that the effects of baryons on the matter power spectrum can be understood at approaching the percent level in terms of the mean baryon fraction of haloes, at scales of up to $k \lesssim 10 \, h \, $Mpc$^{-1}$ and redshifts up to $z=3$. For the range of scales and redshifts that will be probed by forthcoming cosmic shear measurements, most of the effects are driven by galaxy group-mass haloes ($M \sim 10^{13-14}$ M$_\odot$). We present a simple Python implementation of our model, available at $\href{https://github.com/jemme07/pyspk}{\mathrm{https{:}//github.com/jemme07/pyspk}}$, which can be used to incorporate baryon effects in standard gravity-only predictions, allowing for marginalisation over baryon physics within cosmological pipelines.

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J. Salcido, I. McCarthy, J. Kwan, et. al.
Thu, 18 May 23
2/67

Comments: Refereed version accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS). 16 pages, 11 figures

A Simple Code for Rotational Broadening of Broad Wavelength Range High-Dispersion Spectra [IMA]

http://arxiv.org/abs/2305.09693


In high dispersion spectra of rotating bodies such as stars and planets, the rotation contributes significantly to, and sometimes dominates, the line broadening. We present a simple method for rotationally broadening large wavelength ranges of high-dispersion spectra. The broadening is rapid and scales linearly with the length of the spectrum array. For large wavelength ranges, the method is much faster than the popular convolution-based broadening. We provide the code implementation of this method in a publicly accessible repository.

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A. Carvalho and C. Johns-Krull
Thu, 18 May 23
3/67

Comments: 2 pages, 1 figure, published in RNAAS

A non-linear solution to the $S_8$ tension II: Analysis of DES Year 3 cosmic shear [CEA]

http://arxiv.org/abs/2305.09827


Weak galaxy lensing surveys have consistently reported low values of the $S_8$ parameter compared to the $\textit{Planck}\ \Lambda\rm{CDM}$ cosmology. Amon & Efstathiou (2022) used KiDS-1000 cosmic shear measurements to propose that this tension can be reconciled if the matter fluctuation spectrum is suppressed more strongly on non-linear scales than assumed in state-of-the-art hydrodynamical simulations. In this paper, we investigate cosmic shear data from the Dark Energy Survey (DES) Year 3. The non-linear suppression of the matter power spectrum required to resolve the $S_8$ tension between DES and the $\textit{Planck}\ \Lambda\rm{CDM}$ model is not as strong as inferred using KiDS data, but is still more extreme than predictions from recent numerical simulations. An alternative possibility is that non-standard dark matter contributes to the required suppression. We investigate the redshift and scale dependence of the suppression of the matter power spectrum. If our proposed explanation of the $S_8$ tension is correct, the required suppression must extend into the mildly non-linear regime to wavenumbers $k\sim 0.2 h {\rm Mpc}^{-1}$. In addition, all measures of $S_8$ using linear scales should agree with the $\textit{Planck}\ \Lambda\rm{CDM}$ cosmology, an expectation that will be testable to high precision in the near future.

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C. Preston, A. Amon and G. Efstathiou
Thu, 18 May 23
4/67

Comments: 12 pages, 9 figures

Jump-starting relativistic flows, and the M87 jet [HEAP]

http://arxiv.org/abs/2305.09879


We point out the dominant importance of plasma injection effects for relativistic winds from pulsars and black holes. We demonstrate that outside the light cylinder the magnetically dominated outflows while sliding along the helical magnetic field move in fact nearly radially with very large Lorentz factors $\gamma_0 \gg 1 $, imprinted into the flow during pair production within the gaps. Only at larger distances, $r \geq \gamma_0 (c/\Omega)$, the MHD acceleration $\Gamma \propto r$ takes over. As a result, Blandford-Znajek (BZ) driven outflows would produce spine-brightened images, contrary to observations of the edge-brightened jet in M87. We conclude that M87 jet is not BZ-driven. Other implications include: (i) variability time scale of emission even from non-blazar AGNe like M87 and Cen A can be much shorter than the BH spin period; (ii) the model explains blazar-like phenomena in clearly non-aligned AGNe; (iii) in PIC simulations of pulsars’ and black holes’ magnetospheres with pair production, the pairs should be injected with large Lorentz factors – this would drastically change the resulting magnetospheric and inner-wind structure, if compared with pair injection at rest; (iv) the model resolves the problem of cyclotron absorption in the Crab pulsar wind.

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M. Lyutikov and A. Ibrahim
Thu, 18 May 23
5/67

Comments: N/A

Coded Mask Instruments for Gamma-Ray Astronomy [IMA]

http://arxiv.org/abs/2305.10130


Coded mask instruments have been used in high-energy astronomy for the last forty years now and designs for future hard X-ray/low gamma-ray telescopes are still based on this technique when they need to reach moderate angular resolutions over large field of views, particularly for observations dedicated to the, now flourishing, field of time domain astrophysics. However these systems are somehow unfamiliar to the general astronomers as they actually are two-step imaging devices where the recorded picture is very different from the imaged object and the data processing takes a crucial part in the reconstruction of the sky image. Here we present the concepts of these optical systems applied to high-energy astronomy, the basic reconstruction methods including some useful formulae and the trend of the expected and observed performances as function of the system designs. We review the historical developments and recall the flown space-borne coded mask instruments along with the description of a few relevant examples of major successful implementations and future projects in space astronomy.

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A. Goldwurm and A. Gros
Thu, 18 May 23
6/67

Comments: Review (55 pages, 26 figures) published in Handbook of X-ray and Gamma-ray Astrophysics, edited by Cosimo Bambi and Andrea Santangelo, Springer Living Reference Work, ISBN: 978-981-16-4544-0, 2022, id.15

The HI intensity mapping power spectrum: insights from recent measurements [CEA]

http://arxiv.org/abs/2305.09720


The first direct measurements of the HI intensity mapping power spectrum were recently made using the MeerKAT telescope. These measurements are on nonlinear scales, at redshifts 0.32 and 0.44. We develop a formalism for modelling small-scale power in redshift space, within the context of the mass-weighted HI halo model framework. This model is consistent with the latest findings from surveys on the HI-halo mass relation. In order to model nonlinear scales, we include the 1-halo, shot-noise and finger-of-god effects. Then we apply the model to the MeerKAT auto-correlation data, finding that the model provides a good fit to the data at redshift 0.32, but the data may indicate some evidence for an adjustment at $z \sim 0.44$. Such an adjustment can be achieved by an increase in the HI halo model bias.

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H. Padmanabhan, R. Maartens, O. Umeh, et. al.
Thu, 18 May 23
7/67

Comments: 7 pages, 5 figures

Advanced Data Analysis for Observational Cosmology: applications to the study of the Intergalactic Medium [IMA]

http://arxiv.org/abs/2305.10182


The analysis of absorption features along the line of sight to distant sources is an invaluable tool for observational cosmology, giving a direct insight into the physical and chemical state of the inter/circumgalactic medium. Such endeavour entails the accessibility of bright QSOs as background beacons, and the availability of software tools to extract the information in a reproducible way. In this article, we will present the latest results we obtained in both directions within the QUBRICS project: we will describe how machine learning techniques were applied to detect hundreds of previously unknown QSOs in the southern hemisphere, and how state-of-the art software like QSFit and Astrocook was integrated in the analysis of the targets, opening up new possibilities for the next era of observations.

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G. Cupani, G. Calderone, S. Cristiani, et. al.
Thu, 18 May 23
8/67

Comments: 4 pages, 2 figures; proceedings of ADASS XXXI, accepted by ASP Conference Series

Performance of the Quasar Spectral Templates for the Dark Energy Spectroscopic Instrument [IMA]

http://arxiv.org/abs/2305.10426


Millions of quasar spectra will be collected by the Dark Energy Spectroscopic Instrument (DESI), leading to a four-fold increase in the number of known quasars. High accuracy quasar classification is essential to tighten constraints on cosmological parameters measured at the highest redshifts DESI observes ($z>2.0$). We present the spectral templates for identification and redshift estimation of quasars in the DESI Year 1 data release. The quasar templates are comprised of two quasar eigenspectra sets, trained on spectra from the Sloan Digital Sky Survey. The sets are specialized to reconstruct quasar spectral variation observed over separate yet overlapping redshift ranges and, together, are capable of identifying DESI quasars from $0.05 < z <7.0$. The new quasar templates show significant improvement over the previous DESI quasar templates regarding catastrophic failure rates, redshift precision and accuracy, quasar completeness, and the contamination fraction in the final quasar sample.

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A. Brodzeller, K. Dawson, S. Bailey, et. al.
Thu, 18 May 23
9/67

Comments: submitted to Astronomical Journal; 20 pages, 6 figures

Aspherical ULDM Collapse: Variation in the Core-Halo Mass Relation [CEA]

http://arxiv.org/abs/2305.10340


Ultralight dark matter (ULDM) is an interesting alternative to the cold dark matter (CDM) paradigm. Due to the extremely low mass of the constituent particle ($\sim 10^{-22}$ eV), ULDM can exhibit quantum effects up to kiloparsec scales. In particular, runaway collapse in the centres of ULDM halos is prevented by quantum pressure, providing a possible resolution to the ‘core-cusp problem’ of CDM. However, the the detailed relationship between the ULDM core mass and that of the overall halo is poorly understood. We simulate the collapse of both spherical and aspherical isolated ULDM overdensities using AxioNyx, finding that the central cores of collapsed halos undergo sustained oscillatory behaviour which affects both their peak density and overall morphology. The variability in core morphology increases with the asphericity of the initial overdensity and remnants of initial asphericity persist long after collapse. Furthermore, the peak central densities are higher in spherical configurations. Consequently, astrophysically realistic halos may exhibit substantial departures from theoretical core-halo profiles and we would expect a significant variance of the properties of halos with the same mass.

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E. Kendall, M. Gosenca and R. Easther
Thu, 18 May 23
10/67

Comments: 11 pages, 11 figures

White dwarf cooling in $f(R,T)$ gravity [CL]

http://arxiv.org/abs/2305.10144


In recent times, astounding observations of both over- and under-luminous type Ia supernovae have emerged. These peculiar observations hint not only at surpassing the Chandrasekhar limit but may also suggest potential modifications in the physical attributes of their progenitors, such as their cooling rate. This, in turn, can influence their temporal assessments and provide a compelling explanation for these intriguing observations. In this spirit, we investigate here the cooling process of white dwarfs in $f(R,T)$ gravity with the simplest model $f(R,T) = R + \lambda T$, where $\lambda$ is the model parameter. Our modelling suggests that the cooling timescale of white dwarfs exhibits an inverse relationship with the model parameter $\lambda$, which implies that for identical initial conditions, white dwarfs in $f(R,T)$ gravity cool faster. This further unveils that in the realm of $f(R,T)$ gravity, the energy release rate for white dwarfs increases as $\lambda$ increases. Furthermore, we also report that the luminosity of the white dwarfs also depends on $\lambda$ and an upswing in $\lambda$ leads to an amplification in the luminosity, and consequently a larger white dwarf in general relativity can exhibit comparable luminosity to a smaller white dwarf in $f(R,T)$ gravity.

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S. Bhattacharjee
Thu, 18 May 23
11/67

Comments: N/A

The Diffuse Ionized Gas of the Large Magellanic Cloud [GA]

http://arxiv.org/abs/2305.09829


The Large Magellanic Cloud (LMC) has an extensive H${\alpha}$ emission halo that traces an extended, warm ionized component of its interstellar medium. Using the Wisconsin H${\alpha}$ Mapper (WHAM) telescope, we present the first kinematic \ha\ survey of an extensive region around the LMC, from $l,b = (264\deg .5,\,-45\deg .5)$ to $(295\deg .5,\,-19\deg .5)$, covering $+150\leq v_{lsr} \leq +390~ km s^{-1}$. We find that ionized hydrogen exists throughout the galaxy and extends several degrees beyond detected neutral hydrogen emission $(\log{\left(N_{\rm H_{~I}/\rm cm^{-2}}\right)\approx18.3})$ as traced by 21-cm in current surveys. Using the column density structure of the neutral gas and stellar line-of-sight depths as a guide, we estimate the upper limit mass of the ionized component of the LMC to be roughly $M_\mathrm{ionized}\approx (0.6-1.8)\times 10^{9}\,\mathrm{M}{sun}$, which is comparable to the total neutral atomic gas mass in the same region ($M\mathrm{neutral}\approx0.75-0.85\times10^{9}\,\mathrm{M}{sun}$). Considering only the atomic phases, we find $M\mathrm{ionized}/M_\mathrm{ionized+neutral}$, to be 46\%–68\% throughout the LMC and its extended halo. Additionally, we find an ionized gas cloud that extends off of the LMC at $l,b \approx (285\deg, -28\deg)$ into a region previously identified as the Leading Arm complex. This gas is moving at a similar line-of-sight velocity as the LMC and has $M_\mathrm{ionized}/M_\mathrm{ionized+neutral} =$ 13\%–51\%. This study, combined with previous studies of the SMC and extended structures of the Magellanic Clouds, continues to suggest that warm, ionized gas is as massive and dynamically-important as the neutral gas in the Magellanic System.$

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B. Smart, L. Haffner, K. Barger, et. al.
Thu, 18 May 23
12/67

Comments: 20 pages, 12 figures, 4 tables

Left Ringing: Betelgeuse Illuminates the Connection Between Convective outbursts, Mode switching, and Mass Ejection in Red Supergiants [SSA]

http://arxiv.org/abs/2305.09732


Betelgeuse, the nearest red supergiant, dimmed to an unprecedented level in early 2020. The star emerged from this Great Dimming episode with its typical, roughly 400-day pulsation cycle halved, and a new dominant period of around 200 days. The dimming event has been attributed to a surface mass ejection, in which rising material drove shocks through the stellar atmosphere and expelled some material, partially obscuring the star as it formed molecules and dust. In this paper, we use hydrodynamic simulations to reveal the connections between Betelgeuse’s vigorously convective envelope, the surface mass ejection, and the pulsation mode switching that ensued. An anomalously hot convective plume, generated rarely but naturally in the star’s turbulent envelope, can rise and break free from the surface, powering an upwelling that becomes the surface mass ejection. The rising plume also breaks the phase coherence of the star’s pulsation, causing the surface to keep expanding even as the deeper layers contract. This drives a switch from the 400-day fundamental mode of pulsation, in which the whole star expands and contracts synchronously, to the 200-day first overtone, where a radial node separates the interior and exterior of the envelope moving in opposite phase. We predict that the star’s convective motions will damp the overtone oscillation and Betelgeuse will return to its previous, 400-day fundamental mode pulsation in the next 5-10 years. With its resolved surface and unprecedentedly detailed characterization, Betelgeuse opens a window to episodic surface mass ejection in the late-stage evolution of massive stars.

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M. MacLeod, A. Antoni, C. Huang, et. al.
Thu, 18 May 23
13/67

Comments: Submitted to AAS Journals, we welcome comments!

Mitigating the Non-Linearities in a Pyramid Wavefront Sensor [IMA]

http://arxiv.org/abs/2305.09805


For natural guide start adaptive optics (AO) systems, pyramid wavefront sensors (PWFSs) can provide significant increase in sensitivity over the traditional Shack-Hartmann, but at the cost of a reduced linear range. When using a linear reconstructor, non-linearities result in wavefront estimation errors, which can have a significant impact on the image quality delivered by the AO system. Here we simulate a wavefront passing through a PWFS under varying observing conditions to explore the possibility of using a non-linear machine learning model to estimate wavefront errors better than a linear reconstruction. We find significant improvement even with light-weight models, underscoring the need for further investigation of this approach.

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F. Archinuk, R. Hafeez, S. Fabbro, et. al.
Thu, 18 May 23
14/67

Comments: N/A

Detecting Exoplanets Closer to Stars with Moderate Spectral Resolution Integral-Field Spectroscopy [EPA]

http://arxiv.org/abs/2305.10362


While radial velocity surveys have demonstrated that the population of gas giants peaks around $3~\text{au}$, the most recent high-contrast imaging surveys have only been sensitive to planets beyond $\sim~10~\text{au}$. Sensitivity at small angular separations from stars is currently limited by the variability of the point spread function. We demonstrate how moderate-resolution integral field spectrographs can detect planets at smaller separations ($\lesssim~0.3$ arcseconds) by detecting the distinct spectral signature of planets compared to the host star. Using OSIRIS ($R$ $\approx$ 4000) at the W. M. Keck Observatory, we present the results of a planet search via this methodology around 20 young targets in the Ophiuchus and Taurus star-forming regions. We show that OSIRIS can outperform high-contrast coronagraphic instruments equipped with extreme adaptive optics and non-redundant masking in the $0.05-0.3$ arcsecond regime. As a proof of concept, we present the $34\sigma$ detection of a high-contrast M dwarf companion at $\approx0.1$” with a flux ratio of $\approx0.92\%$ around the field F2 star HD 148352. We developed an open-source Python package, breads, for the analysis of moderate-resolution integral field spectroscopy data in which the planet and the host star signal are jointly modeled. The diffracted starlight continuum is forward-modeled using a spline model, which removes the need for prior high-pass filtering or continuum normalization. The code allows for analytic marginalization of linear hyperparameters, simplifying posterior sampling of other parameters (e.g., radial velocity, effective temperature). This technique could prove very powerful when applied to integral field spectrographs like NIRSpec on the JWST and other upcoming first-light instruments on the future Extremely Large Telescopes.

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S. Agrawal, J. Ruffio, Q. Konopacky, et. al.
Thu, 18 May 23
15/67

Comments: Accepted for publication in the Astronomical Journal on May 12, 2023

A catalog of collected debris disks: properties, classifications and correlations between disks and stars/planets [EPA]

http://arxiv.org/abs/2305.10364


We have collected a catalog of 1095 debris disks with properties and classification (resolved, planet, gas) information. From the catalog, we defined a less biased sample with 612 objects and presented the distributions of their stellar and disk properties to search for correlations between disks and stars. We found debris disks were widely distributed from B to M-type stars while planets were mostly found around solar-type stars, gases were easier to detect around early-type stars and resolved disks were mostly distributed from A to G- type stars. The fractional luminosity dropped off with stellar age and planets were mostly found around old stars while gas-detected disks were much younger. The dust temperature of both one-belt systems and cold components in two-belt systems increased with distance while decreasing with stellar age. In addition, we defined a less biased planet sample with 211 stars with debris disks but no planets and 35 stars with debris disks and planets and found the stars with debris disks and planets had higher metallicities than stars with debris disks but no planets. Among the 35 stars with debris disks and planets, we found the stars with disks and cool Jupiters were widely distributed with age from 10 Myr to 10 Gyr and metallicity from -1.56 to 0.28 while the other three groups tended to be old (> 4Gyr) and metal-rich (> -0.3). Besides, the eccentricities of cool Jupiters are distributed from 0 to 0.932 wider than the other three types of planets (< 0.3).

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P. Cao, Q. Liu, N. Liao, et. al.
Thu, 18 May 23
16/67

Comments: 34 pages, 12 figures, 3 tables, Accepted for publication in RAA

Impact of radiative cooling on the magnetised geometrically thin accretion disk around Kerr black hole [HEAP]

http://arxiv.org/abs/2305.09698


It is believed that the spectral state transitions of the outbursts in X-ray binaries (XRBs) are triggered by the rise of the mass accretion rate due to underlying disc instabilities. Recent observations found that characteristics of disc winds are probably connected with the different spectral states, but the theoretical underpinnings of it are highly ambiguous. To understand the correlation between disc winds and the dynamics of the accretion flow, we have performed General Relativistic Magneto-hydrodynamic (GRMHD) simulations of an axisymmetric thin accretion disc with different accretion rates and magnetic field strengths. Our simulations have shown that the dynamics and the temperature properties depend on both accretion rates and magnetic field strengths. We later found that these properties greatly influence spectral properties. We calculated the average coronal temperature for different simulation models, which is correlated with high-energy Compton emission. Our simulation models reveal that the average coronal temperature is anti-correlated with the accretion rates, which is correlated with the magnetic field strengths. We also found that the structured component of the disc winds (Blandford-Payne disc wind) predominates as the accretion rates and magnetic field strengths increase. In contrast, the turbulent component of the disc winds ($B_{\rm tor}$ disc wind) predominates as the accretion rates and magnetic field strengths decrease. Our results suggest that the disc winds during an outburst in XRBs can only be understood if the magnetic field contribution varies over time (e.g., MAXI J1820+070).

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I. Dihingia, Y. Mizuno, C. Fromm, et. al.
Thu, 18 May 23
17/67

Comments: 15 pages, 16 figures

Deep Learning Applications Based on WISE Infrared Data: Classification of Stars, Galaxies and Quasars [IMA]

http://arxiv.org/abs/2305.10217


The Wide-field Infrared Survey Explorer (WISE) has detected hundreds of millions of sources over the entire sky. However, classifying them reliably is a great challenge due to degeneracies in WISE multicolor space and low detection levels in its two longest-wavelength bandpasses. In this paper, the deep learning classification network, IICnet (Infrared Image Classification network), is designed to classify sources from WISE images to achieve a more accurate classification goal. IICnet shows good ability on the feature extraction of the WISE sources. Experiments demonstrates that the classification results of IICnet are superior to some other methods; it has obtained 96.2% accuracy for galaxies, 97.9% accuracy for quasars, and 96.4% accuracy for stars, and the Area Under Curve (AUC) of the IICnet classifier can reach more than 99%. In addition, the superiority of IICnet in processing infrared images has been demonstrated in the comparisons with VGG16, GoogleNet, ResNet34, MobileNet, EfficientNetV2, and RepVGG-fewer parameters and faster inference. The above proves that IICnet is an effective method to classify infrared sources.

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G. Zhao, B. Qiu, A. Luo, et. al.
Thu, 18 May 23
18/67

Comments: N/A

Panchromatic simulated galaxy observations from the NIHAO project [GA]

http://arxiv.org/abs/2305.10232


We present simulated galaxy spectral energy distributions (SEDs) from the far ultraviolet through the far infrared, created using hydrodynamic simulations and radiative transfer calculations, suitable for the validation of SED modeling techniques. SED modeling is an essential tool for inferring star formation histories from nearby galaxy observations, but is fraught with difficulty due to our incomplete understanding of stellar populations, chemical enrichment processes, and the non-linear, geometry dependent effects of dust on our observations. Our simulated SEDs will allow us to assess the accuracy of these inferences against galaxies with known ground truth. To create the SEDs, we use simulated galaxies from the NIHAO suite and the radiative transfer code SKIRT. We explore different sub-grid post-processing recipes, using color distributions and their dependence on axis ratio of galaxies in the nearby universe to tune and validate them. We find that sub-grid post-processing recipes that mitigate limitations in the temporal and spatial resolution of the simulations are required for producing FUV to FIR photometry that statistically reproduce the colors of galaxies in the nearby universe. With this paper we release resolved photometry and spatially integrated spectra for our sample galaxies, each from a range of different viewing angles. Our simulations predict that there is a large variation in attenuation laws among galaxies, and that from any particular viewing angle that energy balance between dust attenuation and reemission can be violated by up to a factor of 3. These features are likely to affect SED modeling accuracy.

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N. Faucher, M. Blanton and A. Macciò
Thu, 18 May 23
19/67

Comments: N/A

An optimized search for dark matter in the galactic halo with HAWC [HEAP]

http://arxiv.org/abs/2305.09861


The Galactic Halo is a key target for indirect dark matter detection. The High Altitude Water Cherenkov (HAWC) observatory is a high-energy (~300 GeV to >100 TeV) gamma-ray detector located in central Mexico. HAWC operates via the water Cherenkov technique and has both a wide field of view of 2 sr and a >95% duty cycle, making it ideal for analyses of highly extended sources. We made use of these properties of HAWC and a new background-estimation technique optimized for extended sources to probe a large region of the Galactic Halo for dark matter signals. With this approach, we set improved constraints on dark matter annihilation and decay between masses of 10 and 100 TeV. Due to the large spatial extent of the HAWC field of view, these constraints are robust against uncertainties in the Galactic dark matter spatial profile.

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A. Albert, R. Alfaro, C. Alvarez, et. al.
Thu, 18 May 23
20/67

Comments: 19 pages, 14 figures

"Dust Giant": Extended and Clumpy Star-Formation in a Massive Dusty Galaxy at $z=1.38$ [GA]

http://arxiv.org/abs/2305.09709


We present NOEMA CO (2-1) line and ALMA 870 $\mu$m continuum observations of a main-sequence galaxy at $z=1.38$. The galaxy was initially selected as a “gas-giant”, based on the gas mass derived from sub-mm continuum (log$(M_{\rm gas}/M_{\odot})=11.20\pm0.20$), however the gas mass derived from CO (2-1) luminosity brings down the gas mass to a value consistent with typical star-forming galaxies at that redshift (log$(M_{\rm gas}/M_{\odot})=10.84\pm0.03$). Despite that the dust-to-stellar mass ratio remains elevated above the scaling relations by a factor of 5. We explore the potential physical picture and consider an underestimated stellar mass and optically thick dust as possible causes. Based on the updated gas-to-stellar mass ratio we rule out the former, and while the latter can contribute to the dust mass overestimate it is still not sufficient to explain the observed physical picture. Instead, possible explanations include enhanced HI reservoirs, CO-dark H$_2$ gas, an unusually high metallicity, or the presence of an optically dark, dusty contaminant. Using the ALMA data at 870 $\mu$m coupled with $HST$/ACS imaging, we find extended morphology in dust continuum and clumpy star-formation in rest-frame UV in this galaxy, and a tentative $\sim 10$ kpc dusty arm is found bridging the galaxy center and a clump in F814W image. The galaxy shows levels of dust obscuration similar to the so-called $HST$-dark galaxies at higher redshifts, and would fall into the optically faint/dark $JWST$ color-color selection at $z>2$. It is therefore possible that our object could serve as low-$z$ analog of the $HST$-dark populations. This galaxy serves as a caveat to the gas masses based on the continuum alone, with a larger sample required to unveil the full picture.

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V. Kokorev, S. Jin, C. Gómez-Guijarro, et. al.
Thu, 18 May 23
21/67

Comments: 9 pages, 5 figures, 1 table. Submitted to A&A Letters

The flattening of dark matter halo of Centaurus A galaxy (NGC 5128) out to 40 kpc [GA]

http://arxiv.org/abs/2305.09822


Cosmological simulations predict dark matter shapes that deviate from spherical symmetry. The exact shape depends on the prescription of the simulation and the interplay between dark matter and baryons. This signature is most pronounced in the diffuse galactic haloes that can be observationally probed with planetary nebulae and globular clusters (GCs). The kinematic observations of these halo tracers support intrinsic triaxial shape for the mass generating the gravitational potential. With discrete axisymmetric modelling of GCs as the halo tracers of NGC 5128 we investigate the overall mass distribution of this nearby giant elliptical galaxy. Our modelling approach constrains $c_{200}$, $(M/L){\star, B}$ and inclination. We derive a preliminary $M{200}\sim 1 \times 10^{12}$ M$\odot$ and flattening $q{\mathrm{DM}}\sim 1.3$ indicative of prolate/triaxial halo for NGC 5128.

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T. Veršič, M. Rejkuba, M. Arnaboldi, et. al.
Thu, 18 May 23
22/67

Comments: 6 pages, 2 figures, Accepted for publication in Proceedings of the IAUS 379: Dynamical Masses of Local Group Galaxies, Potsdam, March 20-24, 2023

An empirical study of dust properties at the earliest epochs [GA]

http://arxiv.org/abs/2305.09714


We present an empirical analysis of the properties of dust-continuum emission in a sample of 17 galaxies in the early Universe ($4 < z < 8$) with well-sampled far-infrared (FIR) spectral energy distributions (SEDs) compiled from the literature. We place our results into context by self-consistently comparing to samples of nearby star-forming galaxies, luminous infrared galaxies (LIRGs), and quasars. With the exception of two sources, we find no significant evolution in the dust emissivity index across cosmic time, measuring a consistent value of $\beta_\text{IR} = 1.8 \pm 0.3$ at $z > 4$, suggesting the effective dust properties do not change dramatically for most galaxies. Despite having comparable stellar masses, we find the high-redshift galaxies to be similar to, or even more extreme than, LIRGs in the HERUS sample in terms of dust temperature ($T_\text{dust} > 40 \, \mathrm{K}$) and IR luminosity ($L_\text{IR} > 10^{11} \, \mathrm{L_\odot}$). We find the dust temperature evolves mildly towards high redshift, though the LIRGs and quasars exhibit elevated temperatures indicating a more efficient and/or additional heating mechanism. Where available, we compare stellar-mass estimates to our inferred dust masses, whose degeneracy with dust temperature can only be mitigated with a well-constrained SED. In merely half of the cases the dust yield may be explained by supernovae alone, with four sources ($44\%$) significantly exceeding a highly optimistic yield where $M_\text{dust} \approx 0.01 M_*$. We discuss possible explanations for this apparent inconsistency and potential observational biases in the measurements of the dust properties of high-redshift galaxies, including in the current IR-bright sample.

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J. Witstok, G. Jones, R. Maiolino, et. al.
Thu, 18 May 23
23/67

Comments: 14 pages, 8 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society

Field-level Lyman-alpha forest modelling in redshift space via augmented non-local Fluctuating Gunn-Peterson Approximation [CEA]

http://arxiv.org/abs/2305.10428


We present an improved analytical model to predict the Lyman-alpha forest at the field level in redshift space from the dark matter field, expanding upon the widely-used Fluctuating Gunn-Peterson approximation (FGPA). In particular, we introduce the dependence on the cosmic web environment (knots, filaments, sheets, voids) in the model, thereby effectively accounting for non-local bias. Furthermore, we include a detailed treatment of velocity bias in the redshift space distortions modelling, allowing the velocity bias to be cosmic-web dependent. We find evidence for a significant difference of the same model parameters in different environments, suggesting that for the investigated setup the simple standard FGPA is not able to adequately predict the Lyman-alpha forest in the different cosmic web regimes. We reproduce the summary statistics of the reference cosmological hydrodynamic simulation we use for comparison, yielding accurate mean transmitted flux, probability distribution function, 3D power spectrum, and bispectrum. In particular, we achieve maximum deviation and average deviations accuracy in the Lyman-alpha forest 3D power spectrum of $\sim 3\%$ and $\sim 0.1\%$ up to $k\sim 0.4 \, h \, {\rm Mpc}^{-1}$, $\sim 5\%$ and $\sim 1.8\%$ up to $k \sim 1.4 \, h \, {\rm Mpc}^{-1}$. Our new model outperforms previous analytical efforts to predict the Lyman-alpha forest at the field level in all the probed summary statistics, and has the potential to become instrumental in the generation of fast accurate mocks for covariance matrices estimation in the context of current and forthcoming Lyman-alpha forest surveys.

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F. Sinigaglia, F. Kitaura, K. Nagamine, et. al.
Thu, 18 May 23
24/67

Comments: 13 pages, 4 figures, 2 tables. Submitted to A&A. Comments welcome

The geometry of the hot corona in MCG-05-23-16 constrained by X-ray polarimetry [HEAP]

http://arxiv.org/abs/2305.10213


We report on the second observation of the radio-quiet active galactic nucleus (AGN) MCG-05-23-16 performed with the Imaging X-ray Polarimetry Explorer (IXPE). The observation started on 2022 November 6 for a net observing time of 640 ks, and was partly simultaneous with NuSTAR (86 ks). After combining these data with those obtained in the first IXPE pointing on May 2022 (simultaneous with XMM-Newton and NuSTAR) we find a 2-8 keV polarization degree $\Pi$ = 1.6 $\pm$ 0.7 (at 68 per cent confidence level), which corresponds to an upper limit $\Pi$ = 3.2 per cent (at 99 per cent confidence level). We then compare the polarization results with Monte Carlo simulations obtained with the MONK code, with which different coronal geometries have been explored (spherical lamppost, conical, slab and wedge). Furthermore, the allowed range of inclination angles is found for each geometry. If the best fit inclination value from a spectroscopic analysis is considered, a cone-shaped corona along the disc axis is disfavoured.

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D. Tagliacozzo, A. Marinucci, F. Ursini, et. al.
Thu, 18 May 23
25/67

Comments: 9 pages, 8 figures, 3 table. Submitted to MNRAS

Investigating kinematics and dynamics of three open clusters towards Galactic anti-center [GA]

http://arxiv.org/abs/2305.10001


We present the intra-cluster kinematics and dynamics of three open clusters: NGC 1193, NGC 2355, and King 12 by incorporating kinematical and photometric data from Gaia DR3, as well as a ground-based telescope. After selecting cluster members based on proper motion data, clusters’ fundamental and structural parameters are investigated. We found the clusters at distances of 4.45, 1.97, and 3.34 kpc from the Sun in the direction of the Galactic anticenter. The luminosity function of the cluster NGC 1193 is flat, whereas it advances towards the fainter ends of the other two clusters. We observed a dip in the luminosity function of King 12. The mass function slopes for all three clusters differ from the solar neighbourhood reported by Salpeter, with NGC 1193 and NGC 2355 being flatter and King 12 having a higher value than the Salpeter value. The intra-cluster kinematics depict that stars in King 12 are moving outwards due to tidal forces from the Galactic disc, which we confirmed by plotting the cluster’s orbit in the Galaxy. Stars in NGC 2355 are moving with smaller relative velocities and have zero mean relative motion, which signifies that the cluster is neither contracting nor evaporating. The Galactic orbits of NGC 1193 suggest that it is orbiting farther from the Galactic disc, and so is less impacted by the Galactic tidal forces.

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G. Rangwal, R. Yadav, D. Bisht, et. al.
Thu, 18 May 23
26/67

Comments: This article has been accepted for the publication in the Monthly Notices of the Royal Astronomical Society and contains total 19 pages, 22 figures and 11 tables

Bounding the mass of ultralight bosonic Dark Matter particles with the motion of the S2 star around Sgr A* [CL]

http://arxiv.org/abs/2305.10242


Dark matter is undoubtedly one of the fundamental, albeit unknown, components of the standard cosmological model. The failure to detect WIMPs, the most promising candidate particle for cold dark matter, actually opens the way for the exploration of viable alternatives, of which ultralight bosonic particles with masses $\sim 10^{-21}$ eV represent one of the most encouraging. N-body simulations have shown that such particles form solitonic cores in the innermost parts of virialized galactic halos that are supported by internal quantum pressure on characteristic $\sim$kpc de Broglie scales. In the Galaxy, this halo region can be probed by means of S-stars orbiting the supermassive black hole Sagittarius A* to unveil the presence of such a solitonic core and, ultimately, to bound the boson mass $m_\psi$. Employing a Monte Carlo Markov Chain algorithm, we compare the predicted orbital motion of S2 with publicly available data and set an upper bound $m_\psi \lesssim 3.2\times 10^{-19}$ eV on the boson mass, at 95% confidence level. When combined with other galactic and cosmological probes, our constraints help to reduce the allowed range of the bosonic mass to $(2.0 \lesssim m_\psi \lesssim 32.2)\times 10^{-20}$ eV, at the 95% confidence level, which opens the way to precision measurements of the mass of the ultralight bosonic dark matter.

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R. Monica and I. Martino
Thu, 18 May 23
27/67

Comments: 5 pages, 2 figures, 1 table. Comments are welcome. Additional plot and related code at this http URL

Multimessenger Constraints on Radiatively Decaying Axions from GW170817 [CL]

http://arxiv.org/abs/2305.10327


The metastable hypermassive neutron star produced in the coalescence of two neutron stars can copiously produce axions that radiatively decay into $\mathcal{O}(100)$~MeV photons. These photons can form a fireball with characteristic temperature smaller than $1\rm\, MeV$. By relying on X-ray observations of GW170817/GRB 170817A with CALET CGBM, Konus-Wind, and Insight-HXMT/HE, we present new bounds on the axion-photon coupling for axion masses in the range $1$-$400\,\rm MeV$. We exclude couplings down to $5\times 10^{-11}\,\rm GeV^{-1}$, complementing and surpassing existing constraints. Our approach can be extended to any feebly-interacting particle decaying into photons.

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M. Diamond, D. Fiorillo, G. Marques-Tavares, et. al.
Thu, 18 May 23
28/67

Comments: 5 pages, 3 figures + 4 pages, 2 figures

SRF Cavity Searches for Dark Photon Dark Matter: First Scan Results [CL]

http://arxiv.org/abs/2305.09711


We present the first use of a tunable superconducting radio frequency cavity to perform a scan search for dark photon dark matter with novel data analysis strategies. We mechanically tuned the resonant frequency of a cavity embedded in the liquid helium with a temperature of $2$ K, scanning the dark photon mass over a frequency range of $1.37$ MHz centered at $1.3$ GHz. By exploiting the superconducting radio frequency cavity’s considerably high quality factors of approximately $10^{10}$, our results demonstrate the most stringent constraints to date on a substantial portion of the exclusion parameter space, particularly concerning the kinetic mixing coefficient between dark photons and electromagnetic photons $\epsilon$, yielding a value of $\epsilon < 2.2 \times 10^{-16}$.

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Z. Tang, B. Wang, Y. Chen, et. al.
Thu, 18 May 23
29/67

Comments: 11 pages, 7 figures

Simple convective accretion flows (SCAFs): Explaining the $\approx-1$ density scaling of hot accretion flows around compact accretors [HEAP]

http://arxiv.org/abs/2305.09737


Recent simulations find that hot gas accretion onto compact accretors are often highly turbulent and diskless, and show power-law density profiles with slope $\alpha_\rho\approx-1$. These results are consistent with observational constraints, but do not match existing self-similar solutions of radiatively inefficient accretion flows. We develop a theory for this new class of accretion flows, which we dub simple convective accretion flows (SCAFs). We use a set of hydrodynamic simulations to provide a minimalistic example of SCAFs, and develop an analytic theory to explain and predict key flow properties. We demonstrate that the turbulence in the flow is driven locally by convection, and argue that radial momentum balance, together with an approximate up-down symmetry of convective turbulence, yields $\alpha_\rho=-1\pm~{\rm few}~0.1$. Empirically, for an adiabatic hydrodynamic flow with $\gamma\approx 5/3$, we get $\alpha_\rho\approx-0.8$; the resulting accretion rate (relative to the Bondi accretion rate), $\dot M/\dot M_{\rm B}\sim (r_{\rm acc}/r_{\rm B})^{0.7}$, agrees very well with the observed accretion rates in Sgr A*, M87*, and a number of wind-fed SgXBs. We also argue that the properties of SCAFs are relatively insensitive to additional physical ingredients such as cooling and magnetic field; this explains its common appearance across simulations of different astrophysical systems.

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W. Xu
Thu, 18 May 23
30/67

Comments: 16 pages, 8 figures. Submitted to AAS journals. Comments are welcome

Frequency-domain approach to self-force in hyperbolic scattering [CL]

http://arxiv.org/abs/2305.09724


We develop a frequency-domain method for calculating the self-force acting on a scalar charge on a fixed scattering geodesic in Schwarzschild spacetime. Existing frequency-domain methods, which are tailored for bound orbits, are inadequate here for several reasons. One must account for the continuous spectrum in the scattering problem, deal with slowly-convergent radial integrals that are hard to evaluate numerically, and confront the inapplicability of the standard self-force method of “extended homogeneous solutions”, which only works for compactly supported sources. We tackle each of these issues in turn, and then present a full numerical implementation, in which we calculate the self-force correction to the scatter angle due to scalar-field back-reaction. We perform a range of internal validation tests, as well as ones based on comparison with existing time-domain results. We discuss the merits and remaining limitations of our method, and outline directions for future work.

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C. Whittall and L. Barack
Thu, 18 May 23
31/67

Comments: 30 pages, 11 figures

The Radio Detector of the Pierre Auger Observatory — status and expected performance [IMA]

http://arxiv.org/abs/2305.10104


As part of the ongoing AugerPrime upgrade of the Pierre Auger Observatory, we are deploying short aperiodic loaded loop antennas measuring radio signals from extensive air showers in the 30-80 MHz band on each of the 1,660 surface detector stations. This new Radio Detector of the Observatory allows us to measure the energy in the electromagnetic cascade of inclined air showers with zenith angles larger than $\sim 65^\circ$. The water-Cherenkov detectors, in turn, perform a virtually pure measurement of the muon component of inclined air showers. The combination of both thus extends the mass-composition sensitivity of the upgraded Observatory to high zenith angles and therefore enlarges the sky coverage of mass-sensitive measurements at the highest energies while at the same time allowing us to cross-check the performance of the established detectors with an additional measurement technique. In this contribution, we outline the concept and design of the Radio Detector, report on its current status and initial results from the first deployed stations, and illustrate its expected performance with a detailed, end-to-end simulation study.

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Tim Huege
Thu, 18 May 23
32/67

Comments: Contribution to the proceedings of the UHECR2022 conference, L’Aquila, Italy

Mass and Color Dependence of the Hubble Spiral Sequence [GA]

http://arxiv.org/abs/2305.09667


In the classic Hubble spiral sequence, arm windiness correlates with bulge size; Sa type spiral galaxies with larger bulges also have the most tightly wound spirals. Exceptions to this have long been known, and in recent work using Galaxy Zoo morphologies no strong correlation was seen in a volume limited sample. In this Research Note, we explore the impact of galaxy mass and integrated color upon this correlation in the Galaxy Zoo sample, finding that bluer and lower mass spirals show the “expected” correlation; however, it becomes slightly negative for redder and/or more massive spiral galaxies.

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P. Mengistu and K. Masters
Thu, 18 May 23
33/67

Comments: 3 pages, 1 figure. Featured in AAS Journal Author Youtube Series: this https URL

On the redshift evolution of the baryon and gas fraction in simulated groups and clusters of galaxies [CEA]

http://arxiv.org/abs/2305.09733


We study the redshift evolution of the baryon budget in a large set of galaxy clusters from the {\it Magneticum} suite of SPH cosmological simulations. At high redshifts, we obtain “closed box” systems independently by the mass of the systems on radii greater than $3R_{500,\mathrm c}$, whereas at lower redshifts, only the most massive halos could be considered as `”closed box”. The baryon fraction shows a general decrease with the redshift and, for less massive objects, we observe a much more prominent decrease than for massive halos. The gas depletion parameter $Y_{\rm gas}$ shows a steeper and highly scattered radial distribution in the central regions of less massive halos with respect to massive objects at all redshifts, while on larger radii the gas fraction distributions are independent of the masses or the redshifts. The hot component of the gas traces well the total amount of gas at low redshifts. At higher redshifts, the cold component provides a not negligible contribution to the total amount of baryon in our systems. Moreover, the behaviour of the baryonic, entire gas, and hot gas phase depletion parameters as a function of radius, mass, and redshift are described by some functional forms. The evolution of metallicity and stellar mass in halos suggests that the early enrichment process is dominant. We investigate correlations between the time evolution of AGN feedback and the depletion parameters. We demonstrate that the energy injected by the AGN activity shows a particularly strong positive correlation with $Y_{\rm bar}$, $Y_{\rm cold}$,$Y_{\rm star}$ and a negative one with $Y_{\rm hot}$, $Z_{\rm Tot}$. These trends are consistent with previous works, meaning that our results, combined with findings derived from current and future X-rays observations, represent possible proxies to test the AGN feedback models used in different suites of numerical simulations.

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M. Angelinelli, S. Ettori, K. Dolag, et. al.
Thu, 18 May 23
34/67

Comments: Accepted in A&A, 15 pages, 11 figures

End-to-end simulation and analysis pipeline for LISA [IMA]

http://arxiv.org/abs/2305.09702


The data produced by the future space-based millihertz gravitational-wave detector LISA will require nontrivial pre-processing, which might affect the science results. It is crucial to demonstrate the feasibility of such processing algorithms and assess their performance and impact on the science. We are building an end-to-end pipeline that includes state-of-the-art simulations and noise reduction algorithms. The simulations must include a detailed model of the full measurement chain, capturing the main features that affect the instrument performance and processing algorithms. In particular, we include in these simulations, for the first time, proper relativistic treatment of reference frames with realistic numerically-optimized orbits; a model for onboard clocks and clock synchronization measurements; proper modeling of total laser frequencies, including laser locking, frequency planning and Doppler shifts; and a better treatment of onboard processing. Using these simulated data, we show that our pipeline is able to reduce the most critical noises and form synchronized observables. By injecting signals from a verification binary, we demonstrate that good parameter estimation can be obtained on this more realistic setup, extending existing results from previous LISA Data Challenges.

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B. Jean-Baptiste, H. Olaf, L. Marc, et. al.
Thu, 18 May 23
35/67

Comments: Moriond Gravitation 2023 Proceedings, 7 pages, 5 figures

Seven Classes of Rotational Variables From a Study of 50,000 Spotted Stars with ASAS-SN, Gaia, and APOGEE [SSA]

http://arxiv.org/abs/2305.09715


We examine the properties of $\sim50,000$ rotational variables from the ASAS-SN survey using distances, stellar properties, and probes of binarity from $\textit{Gaia}$ DR3 and the SDSS APOGEE survey. They have high amplitudes and span a broader period range than previously studied $\textit{Kepler}$ rotators. We find they divide into three groups of main sequence stars (MS1, MS2s, MS2b) and four of giants (G1/3, G2, G4s, and G4b). MS1 stars are slowly rotating (10-30 days), likely single stars with a limited range of temperatures. MS2s stars are more rapidly rotating (days) single stars spanning the lower main sequence up to the Kraft break. There is a clear period gap (or minimum) between MS1 and MS2s, similar to that seen for lower temperatures in the $\textit{Kepler}$ samples. MS2b stars are tidally locked binaries with periods of days. G1/3 stars are heavily spotted, tidally locked RS CVn with periods of tens of days. G2 stars are less luminous, heavily spotted, tidally locked sub-subgiants with periods of $\sim10$ days. G4s stars have intermediate luminosities to G1/3 and G2, slow rotation periods (approaching 100 days) and are almost certainly all merger remnants. G4b stars have similar rotation periods and luminosities to G4s, but consist of sub-synchronously rotating binaries. We see no difference in indicators for the presence of very wide binary companions between any of these groups and control samples of photometric twin stars built for each group.

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A. Phillips, C. Kochanek, T. Jayasinghe, et. al.
Thu, 18 May 23
36/67

Comments: 15 pages, 11 figures, 5 tables, submitted to MNRAS

Warm Molecular Gas in the Central Parsecs of the Buried Nucleus of NGC 4418 Traced with the Fundamental CO Ro-vibrational Absorptions [GA]

http://arxiv.org/abs/2305.09959


We investigated the inner buried nucleus of a nearby luminous infrared galaxy NGC 4418 using high-resolution spectroscopy of fundamental carbon monoxide (CO) ro-vibrational absorptions around $4.67 \mu$m for the first time. This method allowed us to examine the physical and kinematical properties in the hot inner region of this nucleus. We detected a series of both very deep (partly saturated) $^{12}$CO and moderately deep (optically thin) $^{13}$CO absorption lines and inferred a large column density ($N_\mathrm{H2}=(5\pm3)\times10^{23}$ cm$^{-2}$ in front of the $5 \mu$m photosphere) of warm ($T_\mathrm{ex}\simeq170$ K) molecular gas by assuming an isothermal plane-parallel slab illuminated by a compact background MIR-emitting source. We modeled that the warm CO absorber almost covers the central heating source and that it is an inner layer around the $5 \mu$m photosphere (at $r=$several pc) of a compact shroud of gas and dust ($d\sim100$ pc). The width of the absorption lines ($110$ km s$^{-1}$) and their small deviation from the systemic velocity ($<10$ km s$^{-1}$) are consistent with a warm and turbulent layer with little bulk motion in the radial direction.

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Y. Ohyama, S. Onishi, T. Nakagawa, et. al.
Thu, 18 May 23
37/67

Comments: 18 pages, 3 figures, 2 tables, accepted for publication in ApJ

Gravitational Positivity for Phenomenologists: Dark Gauge Boson in the Swampland [CL]

http://arxiv.org/abs/2305.10058


The gravitational positivity bound gives quantitative “swampland” constraints on low-energy effective theories inside theories of quantum gravity. We give a comprehensive discussion of this bound for those interested in applications to phenomenological model building. We present a practical recipe for deriving the bound, and discuss subtleties relevant for realistic models. As an illustration, we study the positivity bound on the scattering of the massive gauge bosons in the Higgs/St\”{u}ckelberg mechanism. Under certain assumptions on gravitational amplitudes at high energy, we obtain a lower bound $m_{V} \gtrsim \Lambda_\mathrm{UV}^2 /g M_\mathrm{Pl}$ on the gauge boson mass $m_V$, where $g$ is the coupling constant of the gauge field, $M_\mathrm{Pl}$ is the reduced Planck mass and $\Lambda_\mathrm{UV}$ is the ultraviolet cutoff of the effective field theory. This bound can strongly constrain new physics models involving a massive gauge boson.

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K. Aoki, T. Noumi, R. Saito, et. al.
Thu, 18 May 23
38/67

Comments: 30 pages, 12 figures

The beaming effect for Fermi-LAT-detected FR-I radio galaxies [HEAP]

http://arxiv.org/abs/2305.10102


Our knowledge of Giga-electron volt (GeV) radio galaxies has been revolutionized by the Fermi-LAT Telescope, which provides an excellent opportunity to study the physical properties of GeV radio galaxies. According to the radio power and morphology, radio galaxies can be separated into Fanaroff-Riley Type I radio galaxies (FR-Is) and Type II radio galaxies (FR-IIs). In this paper, we consider the unification of FR-Is and BL Lacertae objects (BL Lacs), and assume FR-Is to be a standard candle to discuss the beaming effect for Fermi-LAT-detected FR-Is. Our main conclusions are as follows: (1) The estimated Doppler factors for 30 Fermi-LAT-detected FR-Is are in a range of $\delta_{\rm{I}}=0.88-7.49$. The average Doppler factor ($<\delta_{\rm{I}}>=2.56\pm0.30$) of the 30 FR-Is is smaller than that ($<\delta_{\rm{BL}}>=10.28\pm2.03$) of the 126 Fermi-LAT-detected BL Lacs, supporting the unification model that FR-Is are regarded as the misaligned BL Lacs with smaller Doppler factors; (2) We propose that different regions of FR-Is in the plot of the $\gamma$-ray luminosity against the photon spectral index $(\log L_{\gamma}-\alpha_{\rm{ph}})$ may indicate the different beaming effects; (3) The average Doppler factor of the 6 TeV FR-Is is similar to that of the 24 non-TeV FR-Is, which implies that the difference between the TeV and GeV emissions is not driven by the beaming effect in the Fermi-LAT-detected FR-I samples.

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X. Ye, X. Zeng, D. Huang, et. al.
Thu, 18 May 23
39/67

Comments: 15 pages, 6 figures, 2 tables. publication in PASP

Physics-driven machine learning for the prediction of coronal mass ejections' travel times [SSA]

http://arxiv.org/abs/2305.10057


Coronal Mass Ejections (CMEs) correspond to dramatic expulsions of plasma and magnetic field from the solar corona into the heliosphere. CMEs are scientifically relevant because they are involved in the physical mechanisms characterizing the active Sun. However, more recently CMEs have attracted attention for their impact on space weather, as they are correlated to geomagnetic storms and may induce the generation of Solar Energetic Particles streams. In this space weather framework, the present paper introduces a physics-driven artificial intelligence (AI) approach to the prediction of CMEs travel time, in which the deterministic drag-based model is exploited to improve the training phase of a cascade of two neural networks fed with both remote sensing and in-situ data. This study shows that the use of physical information in the AI architecture significantly improves both the accuracy and the robustness of the travel time prediction.

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S. Guastavino, V. Candiani, A. Bemporad, et. al.
Thu, 18 May 23
40/67

Comments: N/A

WIMP decay as a possible Warm Dark Matter model [CEA]

http://arxiv.org/abs/2305.10315


The Weakly Interacting Massive Particles(WIMPs) have long been the favored CDM candidate in the standard $\Lambda$CDM model. However, owing to great improvement in the experimental sensitivity in the past decade, some parameter space of the SUSY-based WIMP model is ruled out. In addition, WIMP as the CDM particle is also at variance with other astrophysical observables at small scales. We consider a model that addresses both these issues. In the model, the WIMP decays into a massive particle and radiation. We study the background evolution and the first order perturbation theory (coupled Einstein-Boltzmann equations) for this model and show that the dynamics can be captured by a single parameter $r=m_L/q$, which is the ratio of the lighter mass and the comoving momentum of the decay particle. We incorporate the relevant equations in the existing Boltzmann code CLASS to compute the matter power spectra and CMB angular power spectra. The decaying WIMP model is akin to a non-thermal Warm Dark Matter(WDM) model and suppresses matter power at small scales, which could alleviate several issues that plague the CDM model. We compare the predictions of the model with CMB, galaxy clustering, and high-z HI data. Both these data sets yield $r\gtrsim 10^6$, which can be translated into the bounds on other parameters. In particular, we obtain the following lower bounds on the self-annihilation cross-section of WIMPs $\sigma$, and the lighter mass $m_L$: $\sigma\gtrsim 5\times 10^{-44}\,\rm cm^2$ and $m_L\gtrsim 2.4\,\rm keV$. The lower limit on $m_L$ is comparable to constraints on the mass of thermally-produced WDM particle. The limit on the self-annihilation cross-section greatly expands the available parameter space as compared to the stable WIMP scenario.

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A. Parichha and S. Sethi
Thu, 18 May 23
41/67

Comments: 24 pages (main text 17 pages), 7 figures, 2 tables

Alive and kicking: A new QPE phase in GSN 069 revealing a quiescent luminosity threshold for QPEs [HEAP]

http://arxiv.org/abs/2305.09717


X-ray quasi-periodic eruptions (QPEs) are intense repeating soft X-ray bursts from the nuclei of nearby galaxies. Their physical origin is still largely unconstrained, and several theoretical models have been proposed to date. We present here results from a recent XMM-Newton observation of GSN 069, the galactic nucleus where QPEs were first discovered. After about two years of absence, QPEs have reappeared in GSN 069, and we detect two consecutive QPEs separated by a much shorter recurrence time than ever before. Moreover, their intensities and peak temperatures are remarkably different, a novel addition to the QPE phenomenology. We study the QPE spectral properties from all XMM-Newton observations assuming QPEs to either represent an additional emission component superimposed on that from the disc, or the transient evolution of the disc emission itself. In the former scenario, QPEs are consistent with black-body emission from a region that expands by a factor of 2-3 during the individual QPE evolution with radius of the order of that of the Sun at QPE peak. In the alternative non-additive scenario, QPEs originate from a region with an area 6-30 times smaller than the quiescent state X-ray emission, with the smallest regions corresponding to the hottest and most luminous eruptions. The QPE reappearance reveals that eruptions are only present below a quiescent luminosity threshold corresponding to an Eddington ratio of the order of 0.4 for a one million solar masses black hole. The disappearance of QPEs above threshold is most likely driven by the ratio of QPE to quiescence temperatures approaching unity at high quiescent luminosity, making QPE detection challenging, if not impossible, above threshold. We briefly discuss some of the consequences of our results on the proposed models for the QPE physical origin. [abridged]

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G. Miniutti, M. Giustini, R. Arcodia, et. al.
Thu, 18 May 23
42/67

Comments: accepted for publication as A&A Letter

Survey for Distant Stellar Aggregates in Galactic Disk: Detecting Two Thousand Star Clusters and Candidates, along with the Dwarf Galaxy IC10 [GA]

http://arxiv.org/abs/2305.10269


Despite having data for over 10^9 stars from Gaia, only less than 10^4 star clusters and candidates have been discovered. Particularly, distant star clusters are rarely identified, due to the challenges posed by heavy extinction and great distance. However, Gaia data has continued to improve, enabling even fainter cluster members to be distinguished from field stars. In this work, we will introduce a star cluster search method based on the DBSCAN algorithm; we have made improvements to make it better suited for identifying clusters on dimmer and more distant stars. After removing member stars of known Gaia-based clusters, we have identified 2086 objects with |b|<10 deg, of which 1488 are highly reliable open star clusters, along with 569 candidates, 28 globular cluster candidates and 1 irregular galaxy IC 10 at low Galactic latitudes. We found that the proper motion of IC10 is similar yet slightly different from the water maser observations, which is an important result for the comparison with Gaia and VLBA. Besides, when compared with the star clusters appearing in Gaia DR2/EDR3, we have found nearly three times as many new objects above a distance of 5 kpc, including hundreds of them above Av > 5 mag. And it has enabled us to detect a higher number of old clusters, over a billion years old, that are difficult to detect due to observational limitations. Our findings significantly expand the remote cluster sample and enhance our understanding of the limits of Gaia DR3 data in stellar aggregates research. The full figure set for 2085 clusters can be seen in \url{https://nadc.china-vo.org/res/r101258/}

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Z. He, Y. Luo, K. Wang, et. al.
Thu, 18 May 23
43/67

Comments: 18 pages, a url link with a full figure set (.pdf file with 88 pages) for 2085 distant clusters in abstract, accepted by ApJS

Reducing the uncertainty on the Hubble constant up to 35\% with an improved statistical analysis: different best-fit likelihoods for Supernovae Ia, Baryon Acoustic Oscillations, Quasars, and Gamma-Ray Bursts [CEA]

http://arxiv.org/abs/2305.10030


Cosmological models and their parameters are widely debated, especially about whether the current discrepancy between the values of the Hubble constant, $H_{0}$, obtained by type Ia supernovae (SNe Ia), and the Planck data from the Cosmic Microwave Background Radiation could be alleviated when alternative cosmological models are considered. Thus, combining high-redshift probes, such as Gamma-Ray Bursts (GRBs) and Quasars (QSOs), together with Baryon Acoustic Oscillations (BAO) and SNe Ia is important to assess the viability of these alternative models and if they can cast further light on the Hubble tension. In this work, for GRBs, we use a 3-dimensional relation between the peak prompt luminosity, the rest-frame time at the end of the X-ray plateau, and its corresponding luminosity in X-rays: the 3D Dainotti fundamental plane relation. Regarding QSOs, we use the Risaliti-Lusso relation among the UV and X-ray luminosities for a sample of 2421 sources. We correct both the QSO and GRB relations by accounting for selection and evolutionary effects with a reliable statistical method. We here use both the traditional Gaussian likelihoods ($\cal L_G$) and the new best-fit likelihoods ($\cal L_N$) to infer cosmological parameters of a non-flat $\Lambda$CDM and flat $w$CDM models. We obtain for all the parameters reduced uncertainties, up to $35\%$ for $H_{0}$, when applying the new $\cal L_N$ likelihoods in place of the Gaussian ones. Our results remain consistent with a flat $\Lambda$CDM model, although with a shift of the dark energy parameter $w$ toward $w<-1$ and a curvature density parameter toward $\Omega_k<0$.

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M. Dainotti, G. Bargiacchi, M. Bogdan, et. al.
Thu, 18 May 23
44/67

Comments: Accepted for publication at ApJ

Spectral Stacking of Radio-Interferometric Data [GA]

http://arxiv.org/abs/2305.10240


Mapping molecular line emission beyond the bright low-J CO transitions is still challenging in extragalactic studies, even with the latest generation of (sub-)mm interferometers, such as ALMA and NOEMA. We summarise and test a spectral stacking method that has been used in the literature to recover low-intensity molecular line emission, such as HCN(1-0), HCO+(1-0), and even fainter lines in external galaxies. The goal is to study the capabilities and limitations of the stacking technique when applied to imaged interferometric observations. The core idea of spectral stacking is to align spectra of the low S/N spectral lines to a known velocity field calculated from a higher S/N line expected to share the kinematics of the fainter line, e.g., CO(1-0) or 21-cm emission. Then these aligned spectra can be coherently averaged to produce potentially high S/N spectral stacks. Here, we use imaged simulated interferometric and total power observations at different signal-to-noise levels, based on real CO observations. For the combined interferometric and total power data, we find that the spectral stacking technique is capable of recovering the integrated intensities even at low S/N levels across most of the region where the high S/N prior is detected. However, when stacking interferometer-only data for low S/N emission, the stacks can miss up to 50% of the emission from the fainter line. A key result of this analysis is that the spectral stacking method is able to recover the true mean line intensities in low S/N cubes and to accurately measure the statistical significance of the recovered lines. To facilitate the application of this technique we provide a public Python package, called PyStacker.

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L. Neumann, J. Brok, F. Bigiel, et. al.
Thu, 18 May 23
45/67

Comments: 10 pages, 10 figures, accepted for pub in A&A, Apr 28, 2023

Role of magnetic pressure forces in Fluctuation dynamo saturation [GA]

http://arxiv.org/abs/2305.09969


Using magnetohydrodynamic simulations of Fluctuation dynamos in turbulent flows with rms Mach numbers $\mathcal{M} \approx 0.2, 1.1$ and $3$, we show that magnetic pressure forces play a crucial role in dynamo saturation in supersonic flows. Firstly, as expected when pressure forces oppose compression, an increase in anti-correlation between density and magnetic field strengths obtains even in subsonic flows with the anti-correlation arising from the intense but rarer magnetic structures. In supersonic flows, due to stronger compressive motions density and magnetic field strength continue to maintain a positive correlation. However, the degree of positive correlation decreases as the dynamo saturates. Secondly, we find that the unit vectors of $\nabla\rho$ and $\nabla B^{2}$ are preferentially anti-parallel to each other in subsonic flows. This is indicative of magnetic pressure opposing compression. This anti-parallel alignment persists in transonic and supersonic flows at dynamo saturation. However, compressive motions also lead to the emergence of a parallel alignment in these flows. Finally, we consider the work done against the components of the Lorentz force and the different sources of magnetic energy growth and dissipation. We show that while in subsonic flows, suppression of field line stretching is dominant in saturating the dynamo, the picture is different in supersonic flows. Both field line stretching and compression amplifies the field initially. But the growing magnetic pressure opposes further compression of magnetic flux which then dominates the saturation of the dynamo.

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S. Sur and K. Subramanian
Thu, 18 May 23
46/67

Comments: Submitted to MNRAS

The signature of galaxy formation models in the power spectrum of the hydrogen 21cm line during reionization [GA]

http://arxiv.org/abs/2305.09721


Observations of the 21cm line of neutral hydrogen are poised to revolutionize our knowledge of cosmic reionization and the high-redshift population of galaxies. However, harnessing such information requires robust and comprehensive theoretical modeling. We study the non-linear effects of hydrodynamics and astrophysical feedback processes, including stellar and AGN feedback, on the 21cm signal by post-processing three existing cosmological hydrodynamical simulations of galaxy formation: Illustris, IllustrisTNG, and Eagle. Overall and despite their different underlying galaxy-formation models, the three simulations return similar predictions for the global 21cm rightness temperature and its power spectrum. At fixed redshift, most differences are attributable to differences in the history of reionization, in turn driven by differences in the build-up of stellar sources of radiation. However, the impact of astrophysics is imprinted in the 21cm power spectrum through several unique signatures. First, we find significant small scale ($k \geq 10\, \rm {Mpc}^{-1}$) differences between Illustris and IllustrisTNG, where higher velocity winds generated by supernova feedback soften density peaks and lead to lower 21cm power in TNG. Second, we find more 21cm power at intermediate scales ($k \approx 0.8\, \rm {Mpc}^{-1}$) in Eagle, due to differences in ionization driven by highly effective stellar feedback, leading to lower star formation, older and redder stellar populations, and thus lower ionizing luminosities. Though subtle, these features could allow future observations of the 21cm signal, in conjunction with other reionization observables, to constrain theoretical models for galactic feedback at high redshift.

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J. Lewis, A. Pillepich, D. Nelson, et. al.
Thu, 18 May 23
47/67

Comments: submitted to MNRAS (12/05/23)

Constraining the Thickness of the Atmosphere of TRAPPIST-1 b from its JWST Secondary Eclipse Observation [EPA]

http://arxiv.org/abs/2305.10414


Recently, the first JWST measurement of thermal emission from a rocky exoplanet was reported. The inferred dayside brightness temperature of TRAPPIST-1 b at 15 $\mu$m is consistent with the planet having no atmosphere and therefore no mechanism by which to circulate heat to its nightside. In this Letter, we compare the measured secondary eclipse depth of TRAPPIST-1 b to predictions from a suite of self-consistent radiative-convective equilibrium models in order to quantify the maximum atmospheric thickness consistent with the observation. We find that plausible atmospheres (i.e., those that contain at least 100 ppm CO$_2$) with surface pressures greater than 0.01 bar (0.1 bar) are ruled out at 1$\sigma$ (3$\sigma$), regardless of the choice of background atmosphere. Thicker atmospheres of up to 10 bar (100 bar) at 1$\sigma$ (3$\sigma$) are only allowed if the atmosphere lacks any strong absorbers across the mid-IR wavelength range, a scenario that we deem unlikely. We additionally model the emission spectra for bare-rock planets of various compositions. We find that a variety of silicate surfaces match the measured eclipse depth to within 1$\sigma$, and the best-fit grey albedo is $0.02 \pm 0.11$. We conclude that planned secondary eclipse observations at 12.8 $\mu$m will serve to validate the high observed brightness temperature of TRAPPIST-1 b, but are unlikely to further distinguish among the consistent atmospheric and bare-rock scenarios.

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J. Ih, E. Kempton, E. Whittaker, et. al.
Thu, 18 May 23
48/67

Comments: 8 pages, 4 figures, submitted to ApJL

Testing 2D temperature models in Bayesian retrievals of atmospheric properties from hot Jupiter phase curves [EPA]

http://arxiv.org/abs/2305.10249


Spectroscopic phase curves of transiting hot Jupiters are spectral measurements at multiple orbital phases, giving a set of disc-averaged spectra that probe multiple hemispheres. By fitting model phase curves to observations, we can constrain the atmospheric properties of hot Jupiters such as molecular abundance, aerosol distribution and thermal structure, which offer insights into their dynamics, chemistry, and formation. In this work, we propose a novel 2D temperature scheme consisting of a dayside and a nightside to retrieve information from near-infrared phase curves, and apply the scheme to phase curves of WASP-43b observed by HST/WFC3 and Spitzer/IRAC. In our scheme, temperature is constant on isobars on the nightside and varies with cos$^n$(longitude/$\epsilon$) on isobars on the dayside, where $n$ and $\epsilon$ are free parameters. We fit all orbital phases simultaneously using the radiative transfer code NEMESISPY coupled to a Bayesian inference code. We first validate the performance of our retrieval scheme with synthetic phase curves generated from a GCM, and find our 2D scheme can accurately retrieve the latitudinally-averaged thermal structure and constrain the abundance of H$_2$O and CH$_4$. We then apply our 2D scheme to the observed phase curves of WASP-43b and find: (1) the dayside temperature-pressure profiles do not vary strongly with longitude and are non-inverted; (2) the retrieved nightside temperatures are extremely low, suggesting significant nightside cloud coverage; (3) the H$_2$O volume mixing ratio is constrained to $5.6\times10^{-5}$–$4.0\times10^{-4}$, and we retrieve an upper bound for CH$_4$ at $\sim$10$^{-6}$.

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J. Yang, P. Irwin and J. Barstow
Thu, 18 May 23
49/67

Comments: 16 pages. 14 figures. Submitted to MNRAS. Comments welcome!

GlobULeS-V. UVIT/AstroSat studies of stellar populations in NGC 362: Detection of Blue Lurkers in a Globular Cluster [SSA]

http://arxiv.org/abs/2305.09723


We report the discovery of four blue lurkers with low and extremely low-mass white dwarf (ELM WDs) companions in the Galactic globular cluster NGC 362 using AstroSat Ultra Violet Imaging Telescope (UVIT). We analyzed the multi-wavelength spectral energy distribution (SED) of FUV-bright MS stars using data from the UVIT, UVOT, GAIA EDR3, and 2.2m ESO/MPI telescopes. Two each of low-mass WDs and ELM WDs are found as companions for the four blue lurkers by the fitting of two-component SED models. The effective temperatures, radii, luminosities, and masses of two low-mass WDs are (35000, 23000) K, (0.04, 0.05) Rsun , (1.45, 0.22) Lsun , and (0.2, 0.2) Msun, while the two ELM WDs are (14750, 14750) K, (0.09, 0.10) Rsun, (0.34, 0.40) Lsun, and (0.18, 0.18) Msun. The position of blue lurkers within the cluster shows that they originated via the Case A/B mass-transfer mechanism in a low-density environment. This is the first detection of blue lurkers with low-mass WDs and ELM WDs as companions in a globular cluster. The companion cooling age is less than 4 Myr, which suggests that they were just recently formed. These binary systems might have originated due to the cluster recent core collapse.

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A. Dattatrey, R. Yadav, G. Kumawat, et. al.
Thu, 18 May 23
50/67

Comments: 6 pages, 3 figures, 1 table

Magnetic Fields and Fragmentation of Filaments in the Hub of California-X [GA]

http://arxiv.org/abs/2305.09949


We present 850 $\mu$m polarization and $\rm C^{18}O (3-2)$ molecular line observations toward the X-shaped nebula in the California molecular cloud using the JCMT SCUBA-2/POL-2 and HARP instruments. The 850 $\mu$m emission shows that the observed region includes two elongated filamentary structures (Fil1 and Fil2) having chains of regularly spaced cores. We measured the mass per unit length of the filament and found that Fil1 and Fil2 are thermally super- and subcritical, respectively, but both are subcritical if nonthermal turbulence is considered. The mean projected spacings ($\Delta\bar S$) of cores in Fil1 and Fil2 are 0.13 and 0.16 pc, respectively. $\Delta\bar S$ are smaller than $4\times$filament width expected in the classical cylinder fragmentation model. The large-scale magnetic field orientations shown by Planck are perpendicular to the long axes of Fil1 and Fil2, while those in the filaments obtained from the high-resolution polarization data of JCMT are disturbed, but those in Fil1 tend to have longitudinal orientations. Using the modified Davis-Chandrasekhar-Fermi (DCF) method, we estimated the magnetic field strengths ($B_{\rm pos}$) of filaments which are 110$\pm$80 and 90$\pm$60 $\mu$G. We calculated the gravitational, kinematic, and magnetic energies of the filaments, and found that the fraction of magnetic energy is larger than 60 % in both filaments. We propose that a dominant magnetic energy may lead the filament to be fragmented into aligned cores as suggested by Tang et al., and a shorter core spacing can be due to a projection effect via the inclined geometry of filaments or due to a non-negligible, longitudinal magnetic fields in case of Fil1.

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E. Chung, C. Lee, W. Kwon, et. al.
Thu, 18 May 23
51/67

Comments: Accepted for publication in the ApJ. 18 pages, 11 figures, 2 tables

Air-Shower Radio Simulations — Where we stand and where we go [IMA]

http://arxiv.org/abs/2305.10100


Simulations of the radio emission from extensive air showers have been key in establishing radio detection as a mature and competitive technique. In particular, microscopic Monte Carlo simulations have proven to very accurately describe the emission physics and are at the heart of practically all analysis approaches. Yet with new applications — for example very inclined air showers, cross-media showers, extreme antenna densities, and higher-frequency measurements — come new challenges for accurate and efficient simulations. I will review the state of the art of the existing simulation approaches and discuss where further improvements might be needed and how they can be achieved.

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T. Huege
Thu, 18 May 23
52/67

Comments: Contribution to the proceedings of the ARENA2022 conference, Santiago de Compostela, Spain

Sustained super-Eddington accretion around neutron stars & black holes [HEAP]

http://arxiv.org/abs/2305.09919


Recently, it was shown that the formation of a photon-trapping surface might not be sufficient to ensure unimpeded super-Eddington (SE) accretion. In light of this finding, here we derive a condition such that sustained and unimpeded SE accretion could be achieved in optically thick slim accretion disks surrounding neutron stars (NSs) and black holes (BHs). For this, we calculate a semi-analytic approximation of the self-similar global radial velocity expression for an advection-dominated flow. Neglecting the influence of relativistic jets on the accretion flow, we find that for Eddington fraction $\dot{m} \gtrsim 1.5 (\epsilon/0.1)^{3/5}$ ($\epsilon$ being the accretion efficiency) sustained SE accretion might be possible in slim disks around BHs irrespective of their spin. The same condition holds for NSs when $\epsilon > 0.03$. The presence of a surface magnetic field might truncate the disk at the magnetosphere of the NS, resulting in lower efficiencies and consequently changing the condition to $\dot{m} > 0.013 \epsilon^{-19/31}$. Our approach suggests that sustained SE accretion might almost always be possible around NSs and BHs hosting accretion disks.

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S. Ghodla and J. Eldridge
Thu, 18 May 23
53/67

Comments: 7 pages, 4 Figures. To appear in MNRAS

An improved Compton parameter map of thermal Sunyaev-Zeldovich effect from Planck PR4 data [CEA]

http://arxiv.org/abs/2305.10193


Taking advantage of the reduced levels of noise and systematics in the data of the latest Planck release (PR4, also known as NPIPE), we construct a new all-sky Compton-$y$ parameter map (hereafter, $y$-map) of the thermal Sunyaev-Zeldovich (SZ) effect from the Planck PR4 data. A tailored Needlet Internal Linear Combination (NILC) pipeline, first validated on detailed sky simulations, is applied to the nine single-frequency Planck PR4 sky maps, ranging from $30$ to $857$ GHz, to produce the PR4 $y$-map over 98% of the sky. Using map comparisons, angular power spectra and one-point statistics we show that the PR4 NILC $y$-map is of improved quality compared to that of the previous PR2 release. The new $y$-map shows reduced levels of large-scale striations associated with $1/f$ noise in the scan direction. Regions near the Galactic plane also show lower residual contamination by Galactic thermal dust emission. At small angular scales, the residual contamination by thermal noise and cosmic infrared background (CIB) emission is found to be reduced by around 7% and 34%, respectively, in the PR4 $y$-map. The PR4 NILC $y$-map is made publicly available for astrophysical and cosmological analyses of the thermal SZ effect.

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J. Chandran, M. Remazeilles and R. Barreiro
Thu, 18 May 23
54/67

Comments: 17 pages, 17 figures, submitted to MNRAS

Constraints on the spectral signatures of superconducting cosmic strings [CEA]

http://arxiv.org/abs/2305.09816


If they exist, networks of superconducting cosmic strings are capable of injecting copious amounts of electromagnetic energy into the background over a broad range of frequencies. We study this injection both analytically, as well as numerically using the thermalization code CosmoTherm. With our refined analytic formalism, we update constraints from CMB spectral distortions by following the injection of entropy, as well as energy, on the amplitude of the $\mu$-distortion, leading to a significant improvement in those limits. Furthermore, we utilize the full shape of the distorted spectrum from CosmoTherm to include constraints from non-$\mu$, non-$y$ type distortions. Additionally, we use the outputs for the ionization history and global 21cm signal to derive and update constraints on string model parameters using measurements from other datasets. Analysis of CMB anisotropies provides the most stringent constraints, though with a slightly modified shape and strength when compared to previous results. Modifications of the reionization history provide new bounds in the high current domain, and we also find that the observations of the low-frequency radio background probe a small region of parameter space not explored by other datasets. We also analyze global $21$-cm constraints, and find that the inclusion of soft photon heating plays a crucial role, essentially removing any constraints in the considered parameter domain. Spectral distortion measurements from COBE/FIRAS are covered by other constraints, but our conservative forecast shows that a PIXIE-type satellite would probe important unexplored regions of parameter space.

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B. Cyr, J. Chluba and S. Acharya
Thu, 18 May 23
55/67

Comments: 21 pages, 24 figures, comments welcome!

Measuring $μ$-Distortions from the Thermal Sunyaev-Zeldovich effect [CEA]

http://arxiv.org/abs/2305.09882


The thermal Sunyaev-Zel’dovich (tSZ) effect is a spectral distortion of the cosmic microwave background (CMB) resulting from inverse Compton scattering of CMB photons with electrons in the medium of galaxy clusters. The spectrum of the tSZ effect is typically calculated assuming the spectrum of the CMB is a blackbody. However, energy or photon number injection at any epoch after photon creation processes become inefficient will distort the blackbody, potentially leading to a chemical potential or $\mu$-distortion for early injection. These $primordial$ spectral distortions will therefore introduce a change in the tSZ effect, effectively a distortion of a distortion. While this effect is small for an individual cluster’s spectrum, upcoming and proposed CMB surveys expect to detect tens of thousands of clusters with the tSZ effect. In this paper, we forecast constraints on the $\mu$-distortion monopole from the distortion of the tSZ spectrum of clusters measured by CMB surveys. We find that planned experiments have the raw sensitivity to place constraints on $\mu$ that are comparable to or better than existing constraints but control over foregrounds and other systematics will be critical.

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D. Zegeye, T. Crawford and W. Hu
Thu, 18 May 23
56/67

Comments: 15 pages, 5 figures