Elasticity of neutron star mantle: improved compressible liquid drop model for cylindrical phases [HEAP]

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http://arxiv.org/abs/2305.03603


Neutron stars are the densest objects in the Universe. They have microscopically homogeneous core and heterogeneous crust. In particular, there may be a specific layer inside neutron stars, the mantle, which consists of substantially non-spherical nuclei immersed in a background of relativistic degenerate electrons and quasi-free neutrons. In this paper we reconsider transverse shear modulus for cylindrical phases of the mantle within the framework of compressible liquid drop model. We demonstrate that transverse shear affects the shape of nuclear clusters: their cross-section becomes elliptical. This effect reduces respective elastic constant. Using a simple model we perform all derivations analytically and obtain the expression for the transverse shear modulus, which can be useful for astrophysical applications.

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N. Zemlyakov and A. Chugunov
Mon, 8 May 23
24/63

Comments: 12 pages, 4 figures, published in Universe

Dark Matter-Induced Stellar Oscillations [CL]

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http://arxiv.org/abs/2305.03085


It has been hypothesized that dark matter is comprised of ultra-light bosons whose collective phenomena can be described as a scalar field undergoing coherent oscillations. Examples include axion and fuzzy dark matter models. In this ultra-light dark matter scenario, the harmonic variation in the field’s energy-momentum tensor sources an oscillating component of the gravitational potential that we show can resonantly-excite stellar oscillations. A mathematical framework for predicting the amplitude of these oscillations is developed, which reveals that ultra-light dark matter predominantly excites p-modes of degree $l=1$. An investigation of resonantly-excited solar oscillations is presented, from which we conclude that dark matter-induced oscillations of the Sun are likely undetectable. We discuss prospects for constraining ultra-light dark matter using other stellar objects.

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J. Sakstein and I. Saltas
Mon, 8 May 23
25/63

Comments: 5 pages, no figures. Comments welcome. A reproduction package for our numerical analysis is available here: this https URL

Tip of the Red Giant Branch Bounds on the Axion-Electron Coupling Revisited [CL]

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http://arxiv.org/abs/2305.03113


We present a novel method to constrain the axion-electron coupling constant using the observed calibration of the tip of the red giant branch (TRGB) I band magnitude $M_I$ that fully accounts for uncertainties and degeneracies with stellar input physics.~We simulate a grid of 116,250 models varying initial mass, helium abundance, and metallicity and train a machine learning emulator to predict $M_I$ as a function of these parameters.~Our emulator enables the use of Markov Chain Monte Carlo simulations where the axion-electron coupling $\alpha_{26}$ is varied simultaneously with the stellar parameters. We find that, once stellar uncertainties and degeneracies are accounted for, the region $\alpha_{26} < 2$ is not excluded by empirical TRGB calibrations.~Our work opens up a large region of parameter space currently believed to be excluded.~$\alpha_{26} = 2$ is the upper limit of the parameter space considered by this study, and it is likely that larger values of $\alpha_{26}$ are also unconstrained.~We discuss potential applications of our work to reevaluate other astrophysical probes of new physics.

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M. Dennis and J. Sakstein
Mon, 8 May 23
26/63

Comments: 14 pages, 6 figures, 1 table, dataset at this https URL

A search for stellar siblings of the ~ 200 Myr TOI-251b planetary system [SSA]

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http://arxiv.org/abs/2305.03255


Young planets (< 1 Gyr) are helpful for studying the physical processes occurring at the early stage of planet evolution. TOI-251 b is a recently discovered sub-Neptune orbiting a young G dwarf, which has an imprecise age estimation of 40-320 Myr. We select TOI-251 sibling candidates based on kinematics and spatial proximity to TOI-251, and further use the color-magnitude diagram (CMD) to refine the list and to compare to multiple open clusters. We report stellar rotational period for 321 sibling candidates in a 50 pc radius around TOI-251 by analyzing their stellar light curves, and find a color – rotational period sequence that lie in between the Group X (300 Myr) and Pleiades (120 Myr) members, suggesting an age ~ 200 Myr. A quantitative age analysis by using gyrochronology relations give 204 $\pm$ 45 Myr, consistent with the average Li-age of selected siblings (238 $\pm$ 38 Myr) and the Gaia variability age (193$^{102}_{-54}$ Myr). The detection fraction of comoving candidates that have short rotational period is 68.1%, much higher than the typical value in the field (14% – 16% from Kepler). The overdensity of young stars and consistency in age of stellar siblings suggest a potential young association candidate in the Pheonix-Grus constellation. Though TOI-251 b has a radius larger than most of its field-age counterparts, we are uncertain whether TOI-251 is inflated due to a lack of knowledge on the planet’s mass.

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Q. Sun, S. Wang, A. Mann, et. al.
Mon, 8 May 23
27/63

Comments: 19 pages, 9 figures, 3 tables, ApJ accepted

Clusters, Clouds, and Correlations: Relating Young Clusters to Giant Molecular Clouds in M33 and M31 [GA]

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http://arxiv.org/abs/2305.03618


We use young clusters and giant molecular clouds (GMCs) in the galaxies M33 and M31 to constrain temporal and spatial scales in the star formation process. In M33, we compare the PHATTER catalogue of 1214 clusters with ages measured via colour-magnitude diagram (CMD) fitting to 444 GMCs identified from a new 35 pc resolution ALMA $^{12}$CO(2-1) survey. In M31, we compare the PHAT catalogue of 1249 clusters to 251 GMCs measured from a CARMA $^{12}$CO(1-0) survey with 20 pc resolution. Through two-point correlation analysis, we find that young clusters have a high probability of being near other young clusters, but correlation between GMCs is suppressed by the cloud identification algorithm. By comparing the positions, we find that younger clusters are closer to GMCs than older clusters. Through cross-correlation analysis of the M33 cluster data, we find that clusters are statistically associated when they are $\leq$10 Myr old. Utilizing the high precision ages of the clusters, we find that clusters older than $\approx 18$ Myr are uncorrelated with the molecular ISM. Using the spatial coincidence of the youngest clusters and GMCs in M33, we estimate that clusters spend $\approx$4-6 Myr inside their parent GMC. Through similar analysis, we find that the GMCs in M33 have a total lifetime of $\approx 11$-15 Myr. We also develop a drift model and show that the above correlations can be explained if the clusters in M33 have a 5-10 km s$^{-1}$ velocity dispersion relative to the molecular ISM.

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J. Peltonen, E. Rosolowsky, L. Johnson, et. al.
Mon, 8 May 23
28/63

Comments: 14 pages, 13 figures, 1 tables, accepted for publication at MNRAS

CHEX-MATE: Constraining the origin of the scatter in galaxy cluster radial X-ray surface brightness profiles [CEA]

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http://arxiv.org/abs/2305.03082


We investigate the statistical properties and the origin of the scatter within the spatially resolved surface brightness profiles of the CHEX-MATE sample, formed by 118 galaxy clusters selected via the SZ effect. These objects have been drawn from the Planck SZ catalogue and cover a wide range of masses, M${500}=[2-15] \times 10^{14} $M${\odot}$, and redshift, z=[0.05,0.6]. We derived the surface brightness and emission measure profiles and determined the statistical properties of the full sample. We found that there is a critical scale, R$\sim 0.4 R_{500}$, within which morphologically relaxed and disturbed object profiles diverge. The median of each sub-sample differs by a factor of $\sim 10$ at $0.05\,R_{500}$. There are no significant differences between mass- and redshift-selected sub-samples once proper scaling is applied. We compare CHEX-MATE with a sample of 115 clusters drawn from the The Three Hundred suite of cosmological simulations. We found that simulated emission measure profiles are systematically steeper than those of observations. For the first time, the simulations were used to break down the components causing the scatter between the profiles. We investigated the behaviour of the scatter due to object-by-object variation. We found that the high scatter, approximately 110%, at $R<0.4R_{500}$ is due to a genuine difference between the distribution of the gas in the core. The intermediate scale, $R_{500} =[0.4-0.8]$, is characterised by the minimum value of the scatter on the order of 0.56, indicating a region where cluster profiles are the closest to the self-similar regime. Larger scales are characterised by increasing scatter due to the complex spatial distribution of the gas. Also for the first time, we verify that the scatter due to projection effects is smaller than the scatter due to genuine object-by-object variation in all the considered scales. [abridged]

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I. Bartalucci, S. Molendi, E. Rasia, et. al.
Mon, 8 May 23
29/63

Comments: Accepted for publication in A&A

Gas, dust, and the CO-to-molecular gas conversion factor in low-metallicity starbursts [GA]

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http://arxiv.org/abs/2305.03443


The factor relating CO emission to molecular hydrogen column density, XCO, is still subject to uncertainty, in particular at low metallicity. Here, to quantify XCO at two different spatial resolutions, we exploit a dust-based method together with ALMA 12-m and ACA data and HI maps of three nearby metal-poor starbursts, NGC625, NGC1705, and NGC5253. Dust opacity at 250pc resolution is derived based on dust temperatures estimated by fitting two-temperature modified blackbodies to Herschel PACS data. By using the HI maps, we are then able to estimate dust-to-gas ratios in the atomic-gas dominated regions, and infer total gas column densities and H2 column densities as the difference with HI. Finally, from the ACA CO(1-0) maps, we derive XCO. We use a similar technique with 40 pc ALMA 12-m data for the three galaxies, but instead derive dust attenuation at 40 pc resolution from reddening maps based on VLT/MUSE data. At 250 pc resolution, XCO $\sim$ 10^22 – 10^23 cm^-2 / K.km/s, 5-1000 times the Milky Way value, with much larger values than would be expected from a simple metallicity dependence. Instead at 40 pc resolution, XCO again shows large variation, but is roughly consistent with a power-law metallicity dependence, given the Z $\sim$ 1/3 Zsun metal abundances of our targets. The large scatter in both estimations could imply additional parameter dependence, that we have investigated by comparing XCO with the observed velocity-integrated brightness temperatures, ICO, as predicted by recent simulations. Indeed, larger XCO is significantly correlated with smaller ICO, but with slightly different slopes and normalizations than predicted by theory. Such behavior can be attributed to the increasing fraction of CO-faint H2 gas with lower spatial resolution. This confirms the idea the XCO is multi-variate, depending not only on metallicity but also on CO brightness temperature and beam size.

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L. Hunt, F. Belfiore, F. Lelli, et. al.
Mon, 8 May 23
30/63

Comments: A&A, submitted, revision after referee report: 16 figures, 1 appendix

Constraints on Undetected Long-Period Binaries in the Known Pulsar Population [HEAP]

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http://arxiv.org/abs/2305.03561


Although neutron star-black hole binaries have been identified through mergers detected in gravitational waves, a pulsar-black hole binary has yet to be detected. While short-period binaries are detectable due to a clear signal in the pulsar’s timing residuals, effects from a long-period binary could be masked by other timing effects, allowing them to go undetected. In particular, a long-period binary measured over a small subset of its orbital period could manifest via time derivatives of the spin-frequency incompatible with isolated pulsar properties. We assess the possibility of pulsars having unknown companions in long-period binaries and put constraints on the range of binary properties that may remain undetected in current data, but that may be detectable with further observations. We find that for 35% of canonical pulsars with published higher order derivatives, the precision of measurements is not enough to confidently reject binarity (period greater than ~2 kyr), and that a black-hole binary companion could not be ruled out for a sample of pulsars without published constraints if the period is greater than 1 kyr. While we find no convincing cases in the literature, we put more stringent limits on orbital period and longitude of periastron for the few pulsars with published higher-order frequency derivatives (n greater than 3). We discuss the detectability of candidates and find that a sample pulsar in a 100 yr orbit could be detectable within 5-10 yr.

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M. Jones, D. Kaplan, M. McLaughlin, et. al.
Mon, 8 May 23
31/63

Comments: 9 pages, 5 figures. Accepted to ApJ

Extreme evaporation of planets in hot thermally unstable protoplanetary discs: the case of FU Ori [EPA]

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http://arxiv.org/abs/2305.03392


Disc accretion rate onto low mass protostar FU Ori suddenly increased hundreds of times 85 years ago and remains elevated to this day. We show that the sum of historic and recent observations challenges existing FU Ori models. We build a theory of a new process, Extreme Evaporation (EE) of young gas giant planets in discs with midplane temperatures exceeding 30, 000 K. Such temperatures are reached in the inner 0.1 AU during thermal instability bursts. In our 1D time-dependent code the disc and an embedded planet interact through gravity, heat, and mass exchange. We use disc viscosity constrained by simulations and observations of dwarf novae instabilities, and we constrain planet properties with a stellar evolution code. We show that dusty gas giants born in the outer self-gravitating disc reach the innermost disc in a $\sim$ 10,000 years with radius of $\sim 10 R_J$. We show that their EE rates are $\sim 10^{-5}$ Msun/yr; if this exceeds the background disc accretion activity then the system enters a planet-sourced mode. Like a stellar secondary in mass-transferring binaries, the planet becomes the dominant source of matter for the star, albeit for $\sim$ O(100) years. We find that a $\sim$ 6 Jupiter mass planet evaporating in a disc fed at a time-averaged rate of $\sim 10^{-6}$ Msun/yr appears to explain all that we currently know about FU Ori accretion outburst. More massive planets and/or planets in older less massive discs do not experience EE process. Future FUOR modelling may constrain planet internal structure and evolution of the earliest discs.

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S. Nayakshin, J. Owen and V. Elbakyan
Mon, 8 May 23
32/63

Comments: Accepted to MNRAS

Site-testing at the Muztagh-ata Site.V. Nighttime Cloud Amount during the Last Five Years [IMA]

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http://arxiv.org/abs/2305.03067


The clarity of nights is the major factor that should be carefully considered for optical/infrared astronomical observatories in site-testing campaigns. Cloud coverage is directly related to the amount of time available for scientific observations at observatories. In this article, we report on the results of detailed night-time cloud statistics and continuous observing me derived from ground-based all-sky cameras at the Muztagh-ata site from 2017 to 2021. Results obtained from acquisition data show that the proportion of the annual observing me at the Muztagh-ata site is 65%, and the best period with the least cloud coverage and longer continuous observing time is from September to February. We made a comparison of the monthly mean observing nights obtained from our all-sky cameras and CLARA dataset, results show that the discrepancy between them may depend on the cloud top heights. On average, this site can provide 175 clear nights and 169 nights with at least 4 hours of continuous observing time per year.

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J. Xu, G. Feng, G. Pu, et. al.
Mon, 8 May 23
33/63

Comments: 11 pages, 9 figures

Misalignment and mode mismatch error signals for higher-order Hermite-Gauss modes from two sensing schemes [IMA]

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http://arxiv.org/abs/2305.03658


The locking of lasers to optical cavities is ubiquitously required in the field of precision interferometry such as Advanced LIGO to yield optimal sensitivity. Using higher-order Hermite-Gauss (HG) modes for the main interferometer beam has been a topic of recent study, due to their potential for reducing thermal noise of the test masses. It has been shown however that higher-order HG modes are more susceptible to coupling losses into optical cavities: the misalignment and mode mismatch induced power losses scale as $2n+1$ and $n^{2}+n+1$ respectively with $n$ being the mode index. In this paper we calculate analytically for the first time the alignment and mode mismatch sensing signals for arbitrary higher-order HG modes with both the traditional sensing schemes (using Gouy phase telescopes and quadrant photodetectors) and the more recently proposed radio-frequency jitter-based sensing schemes (using only single element photodiodes). We show that the sensing signals and also the signal-to-shot noise ratios for higher-order HG modes are larger than for the fundamental mode. In particular, the alignment and mode mismatch sensing signals in the traditional sensing schemes scale approximately as $\sqrt{n}$ and $n$ respectively, whereas in the jitter-based sensing schemes they scale exactly as $2n+1$ and $n^{2}+n+1$, respectively, which exactly matches the decrease in their respective tolerances. This potentially mitigates the downside of higher-order HG modes for their suffering from excessive misalignment and mode-mismatch induced power losses.

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L. Tao, A. Green and P. Fulda
Mon, 8 May 23
34/63

Comments: 11 pages 6 figures

The maximum mass and deformation of rotating strange quark stars with strong magnetic fields [HEAP]

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http://arxiv.org/abs/2305.03055


We study the structure and total energy of a strange quark star (SQS) endowed with a strong magnetic field with different rotational frequencies. The MIT bag model is used, with the density-dependent bag constant for the equation of state (EOS). The EOS is computed considering the Landau quantization effect regarding the strong magnetic fields (up to $5\times10^{17}$ G) in the interior of the strange quark star. Using the LORENE library, we calculate the structural parameters of SQS for different setups of magnetic field strengths and rotational frequencies. In each setup, we perform calculations for $51$ stellar configurations, with specified central enthalpy values. We investigate the configurations with the maximum gravitational mass of SQS in each setup. Our models of SQSs are compared in the maximum gravitational mass, binding energy, compactness, and deformation of the star. We show that the gravitational mass might exceed $2.3 M_\odot$ in some models, which is comparable with the mass of the recently detected “black widow” pulsar \emph{PSR J0952-0607} and the mass of \emph{GW190814} detected by the LIGO/Virgo collaboration. The deformation and maximum gravitational mass of SQS can be characterized by simple functions that have been fitted to account for variations in both magnetic field strength and frequency. Rapidly rotating strange stars have a minimum gravitational mass given by the equatorial mass-shedding limit.

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F. Kayanikhoo, M. Kapusta and M. Čemeljić
Mon, 8 May 23
35/63

Comments: 18 pages, 10 Figures, 2 tables, submitted to PhysRevD

The impact of HII regions on Giant Molecular Cloud properties in nearby galaxies sampled by PHANGS ALMA and MUSE [GA]

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http://arxiv.org/abs/2305.03650


We identify giant molecular clouds (GMCs) associated with HII regions for a sample of 19 nearby galaxies using catalogs of GMCs and H regions released by the PHANGS-ALMA and PHANGS-MUSE surveys, using the overlap of the CO and H{\alpha} emission as the key criterion for physical association. We compare the distributions of GMC and HII region properties for paired and non-paired objects. We investigate correlations between GMC and HII region properties among galaxies and across different galactic environments to determine whether GMCs that are associated with HII regions have significantly distinct physical properties to the parent GMC population. We identify trends between the H{\alpha} luminosity of an HII region and the CO peak brightness and the molecular mass of GMCs that we tentatively attribute to a direct physical connection between the matched objects, and which arise independently of underlying environmental variations of GMC and HII region properties within galaxies. The study of the full sample nevertheless hides a large variability galaxy by galaxy. Our results suggests that at the ~100 pc scales accessed by the PHANGS-ALMA and PHANGS-MUSE data, pre-supernova feedback mechanisms in HII regions have a subtle but measurable impact on the properties of the surrounding molecular gas, as inferred from CO observations.

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A. Zakardjian, J. Pety, C. Herrera, et. al.
Mon, 8 May 23
36/63

Comments: N/A

The Early Light Curve of SN 2023bee: Constraining Type Ia Supernova Progenitors the Apian Way [HEAP]

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http://arxiv.org/abs/2305.03071


We present very early photometric and spectroscopic observations of the Type Ia supernova (SN) 2023bee, starting about 8 hours after the explosion, which reveal a strong excess in the optical and nearest UV (U and UVW1) bands during the first several days of explosion. This data set allows us to probe the nature of the binary companion of the exploding white dwarf and the conditions leading to its ignition. We find a good match to the Kasen model in which a main-sequence companion star stings the ejecta with a shock as they buzz past. Models of double detonations, shells of radioactive nickel near the surface, interaction with circumstellar material, and pulsational-delayed detonations do not provide good matches to our light curves. We also observe signatures of unburned material, in the form of carbon absorption, in our earliest spectra. Our radio non-detections place a limit on the mass-loss rate from the putative companion that rules out a red giant but allows a main-sequence star. We discuss our results in the context of other similar Type Ia SNe in the literature.

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G. Hosseinzadeh, D. Sand, S. Sarbadhicary, et. al.
Mon, 8 May 23
37/63

Comments: submitted to ApJL

Complete replacement of magnetic flux in a flux rope during a coronal mass ejection [SSA]

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http://arxiv.org/abs/2305.03217


Solar coronal mass ejections are the most energetic events in the Solar System. In their standard formation model, a magnetic flux rope builds up into a coronal mass ejection through magnetic reconnection that continually converts overlying, untwisted magnetic flux into twisted flux enveloping the pre-existing rope. However, only a minority of coronal mass ejections carry a coherent magnetic flux rope as their core structure, which casts doubt on the universality of this orderly wrapping process. Here we provide observational evidence of a different formation and eruption mechanism of a magnetic flux rope from an S-shaped thread, where its magnetic flux is fully replaced via flare reconnections. One of the footpoints of the sigmoidal feature slipped and expanded during the formation, and then moved to a completely new place, associated with the highly dynamical evolution of flare ribbons and a twofold increase in magnetic flux through the footpoint, during the eruption. Such a configuration is not predicted by standard formation models or numerical simulations and highlights the three-dimensional nature of magnetic reconnections between the flux rope and the surrounding magnetic field.

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T. Gou, R. Liu, A. Veronig, et. al.
Mon, 8 May 23
38/63

Comments: N/A

Weighing Andromeda: Mass estimates of the M~31 galaxy [GA]

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http://arxiv.org/abs/2305.03293


Andromeda (M 31) is the nearest giant spiral galaxy to our Milky Way, and over the past few decades, has been dubbed the most massive member of the Local Group. I explore the evolution of the measured mass of M 31 over the past ~80 years, reviewing the different observational and modelling techniques that have developed over time to measure its mass. I discuss the best present-day constraints of the mass of M 31 and the consistency of different techniques.

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S. Bhattacharya
Mon, 8 May 23
39/63

Comments: 9 pages, 1 figure, 1 table, Proceedings of the IAUS 379: Dynamical Masses of Local Group Galaxies, Potsdam, March 20-24, 2023

Black Holes as the source of the dark energy: a stringent test with the high-redshift JWST AGNs [CEA]

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http://arxiv.org/abs/2305.03408


It has been suggested that there is evidence for cosmological coupling of black holes (BHs) with an index of $k\approx 3$ and hence the BHs serve as the astrophysical source of the dark energy. The data sample however is limited for the redshifts $\leq 2.5$. Recently, the James Webb Space Telescope (JWST) has detected more than 180 high-redshift Active Galactic Nuclei (AGNs) and quasars. Among the JWST NIRSpec/NIRCam resolved AGNs, three are identified in early-type host galaxies with a redshift $z\sim 4.5-7$. Their $M_{\star}$ and $M_{\rm BH}$, however, are in tension with the prediction of the cosmological coupling of black holes with $k=3$ at a confidence level of $\sim 3\sigma$, which is not in support of the hypothesis that BHs serve as the origin of dark energy. The future observations of high-redshift AGNs by JWST will further test such a hypothesis by identifying more early-type host galaxies in the higher mass range.

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L. Lei, L. Zu, G. Yuan, et. al.
Mon, 8 May 23
40/63

Comments: 9 pages, 3 figures, 1 table; Submitted to ApJL. Comments are welcome!

A Census of the TW Hya Association with Gaia [GA]

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http://arxiv.org/abs/2305.03557


I have used high-precision photometry and astrometry from the third data release of Gaia to perform a survey for members of the TW Hya association (TWA). I have identified candidate members that appear to share similar kinematics and ages with bona fide members compiled by Gagne et al. (2017) and I have assessed their membership using radial velocities and spectroscopic diagnostics of age from various sources. My new catalog of adopted members contains 67 Gaia sources in 55 systems. The histogram of spectral types for TWA peaks near M5 (~0.15 Msun), resembling the distributions measured for other nearby young associations. The UVW velocities of its members indicate that the association is expanding. The rate of expansion corresponds to an age of 9.6+0.9/-0.8 Myr. In a Gaia color-magnitude diagram, the members of TWA exhibit well-defined sequences of single stars and unresolved binary stars. The combined sequence of low-mass stars in TWA is indicative of an age of 11.4+1.3/-1.2 Myr when compared to the sequence for Upper Centaurus-Lupus/Lower Centaurus-Crux, for which an age of 20 Myr is assumed. Based on these expansion and isochronal ages, I have adopted an age of 10+/-2 Myr for TWA. Finally, I have used mid-infrared photometry from the Wide-field Infrared Survey Explorer to check for excess emission from circumstellar disks among the TWA members. Fourteen members have detected disks, all of which have been reported in previous studies. The fraction of members at <=M6 (>=0.1 Msun) that have full, transitional, or evolved disks is 10/52=0.19+0.08/-0.06. That value is similar to the fraction previously measured for the Upper Sco association, which is roughly coeval with TWA.

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K. Luhman
Mon, 8 May 23
41/63

Comments: The Astronomical Journal, in press

Challenging interferometric imaging: Machine learning-based source localization from uv-plane observations [IMA]

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http://arxiv.org/abs/2305.03533


In our work, we examine, for the first time, the possibility of fast and efficient source localization directly from the uvobservations, omitting the recovering of the dirty or clean images. We propose a deep neural network-based framework that takes as its input a low-dimensional vector of sampled uvdata and outputs source positions on the sky. We investigated a representation of the complex-valued input uv-data via the real and imaginary and the magnitude and phase components. We provided a comparison of the efficiency of the proposed framework with the traditional source localization pipeline based on the state-of-the-art Python Blob Detection and Source Finder (PyBDSF) method. The investigation was performed on a data set of 9164 sky models simulated using the Common Astronomy Software Applications (CASA) tool for the Atacama Large Millimeter Array (ALMA) Cycle 5.3 antenna configuration. We investigated two scenarios: (i) noise-free as an ideal case and (ii) sky simulations including noise representative of typical extra-galactic millimeter observations. In the noise-free case, the proposed localization framework demonstrates the same high performance as the state-of-the-art PyBDSF method. For noisy data, however, our new method demonstrates significantly better performance, achieving a completeness level that is three times higher for sources with uniform signal-to-noise (S/N) ratios between 1 and 10, and a high increase in completeness in the low S/N regime. Furthermore, the execution time of the proposed framework is significantly reduced (by factors about 30) as compared to traditional methods that include image reconstructions from the uv-plane and subsequent source detections.

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O. Taran, O. Bait, M. Dessauges-Zavadsky, et. al.
Mon, 8 May 23
42/63

Comments: N/A

Forbidden planetesimals [EPA]

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http://arxiv.org/abs/2305.03562


Planetesimals are born fragile and are subject to destruction by wind erosion as they move through the gas of a protoplanetary disk. In microgravity experiments, we determined the shear stress necessary for erosion of a surface consisting of 1 mm dust pebbles down to 1 Pa ambient pressure. This is directly applicable to protoplanetary disks. Even pebble pile planetesimals with low eccentricities of 0.1 cannot survive inside of 1 au in a minimum-mass solar nebula, and safe zones for planetesimals with higher eccentricities are located even farther out.

Read this paper on arXiv…

L. Schönau, J. Teiser, T. Demirci, et. al.
Mon, 8 May 23
43/63

Comments: N/A

Spectrogram correlated stacking: A novel time-frequency domain analysis of the Stochastic Gravitational Wave Background [CL]

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http://arxiv.org/abs/2305.03090


The astrophysical stochastic gravitational wave background (SGWB) originates from numerous faint sub-threshold gravitational wave (GW) signals arising from the coalescing binary compact objects. This background is expected to be discovered from the current (or next-generation) network of GW detectors by cross-correlating the signal between multiple pairs of GW detectors. However, detecting this signal is challenging and the correlation is only detectable at low frequencies due to the arrival time delay between different detectors. In this work, we propose a novel technique, \texttt{Spectrogram Correlated Stacking} (or \texttt{SpeCs}), which goes beyond the usual cross-correlation (and to higher frequencies) by exploiting the higher-order statistics in the time-frequency domain which accounts for the \textit{chirping} nature of the individual events that comprise SGWB. We show that \texttt{SpeCs} improves the signal-to-noise for the detection of SGWB by a factor close to $8$, compared to standard optimal cross-correlation methods which are tuned to measure only the power spectrum of the SGWB signal.\texttt{SpeCs} can probe beyond the power spectrum and its application to the GW data available from the current and next-generation GW detectors would speed up the SGWB discovery.

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R. Dey, L. Micchi, S. Mukherjee, et. al.
Mon, 8 May 23
44/63

Comments: N/A

Beam displacement tolerances on a segmented mirror for higher-order Hermite-Gauss modes [IMA]

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http://arxiv.org/abs/2305.03681


Odd-indexed higher-order Hermite-Gauss (HG) modes are compatible with 4-quadrant segmented mirrors due to their intensity nulls along the principal axes, which guarantees minimum beam intensity illuminating the bond lines between the segments thus leading to low power loss. However, a misplaced HG beam can cause extra power loss due to the bright intensity spots probing the bond lines. This paper analytically and numerically studies the beam displacement tolerances on a segmented mirror for the $\mathrm{HG_{3,3}}$ mode. We conclude that for “effective” bond lines with 6 $\mu$m width, and the $\mathrm{HG_{3,3}}$ beam size chosen to guarantee 1 ppm clipping loss when centered, the beam can be rotated by roughly 1 degree or laterally displaced by 4% of its beam size while keeping the total power on the bond lines under 1 ppm. We also demonstrate that the constrained beam displacement parameter region that guarantees a given power loss limit, or the beam displacement tolerance, is inversely proportional to the bond line thickness.

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L. Tao, N. Brown and P. Fulda
Mon, 8 May 23
45/63

Comments: 4 pages, 6 pages

A Chandra X-ray Study of Supernova Remnant N63A in the Large Magellanic Cloud [HEAP]

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http://arxiv.org/abs/2305.03084


We perform extensive spectroscopy of the supernova remnant N63A in the Large Magellanic Cloud, using $\sim 43$ ks {\it Chandra} archival data. By analysing the spectra of the entire remnant, we determine the abundance distributions for O, Ne, Mg, Si, and Fe. We detect evidence of enhanced O and possibly Ne and Mg in some of the central regions which might indicate an asymmetric distribution of the ejecta. The average O/Ne, O/Mg, and Ne/Mg abundance ratios of the ejecta are in plausible agreement with the nucleosynthesis products from the explosion of a $\sim40$ $M_{\odot}$ progenitor. We estimate an upper limit on the Sedov age of $\sim 5,400\pm200$ yr and explosion energy of $\sim 8.9\pm 1.6\times 10^{51}$ erg for N63A. We discuss the implications of our results for the morphological structure of the remnant, its circumstellar medium and the nature of the progenitor star.

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E. Karagoz, N. Alan, S. Bilir, et. al.
Mon, 8 May 23
46/63

Comments: 22 pages, including 9 figures and 4 tables, accepted for publication in Monthly Notices of the Royal Astronomical Society. arXiv admin note: substantial text overlap with arXiv:2201.09891

Gravitational freeze-in dark matter from Higgs Preheating [CL]

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http://arxiv.org/abs/2305.02568


Gravitational freeze-in is a mechanism to explain the observed dark matter relic density if dark matter neither couples to inflation nor to standard model sector. In this work, we study gravitational freeze-in dark matter production during Higgs preheating based on non-perturbative resonance. Using reliable lattice method to handle this non-perturbative process, we show that tachyonic resonance is prohibited by strong back reaction due to Higgs self interaction needed to keep the positivity of potential during preheating, and parameter resonance is viable by tuning the Higgs self-interaction coupling to be small enough in ultraviolet energy scale. We then derive the dark matter relic density under the context of Higgs preheating, and uncover a new dark matter parameter space with dark matter mass larger than inflaton mass, which arises from out-of-equilium Higgs annihilation. Finally, we briefly remark the open question of testing gravitational dark matter.

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R. Zhang, Z. Xu and S. Zheng
Mon, 8 May 23
47/63

Comments: 18 pages, 5 figures

Influence of the Lower Atmosphere on Wave Heating and Evaporation in Solar Coronal Loops [SSA]

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http://arxiv.org/abs/2305.03621


We model a coronal loop as a three-dimensional magnetic cylinder in a realistic solar atmosphere that extends from the chromosphere to the corona. Kink oscillations, believed ubiquitous in the solar corona, are launched in the loop. Heating is expected due to the dissipation of wave energy at small structures that develop from the Kelvin-Helmholtz instability induced by kink oscillations. Increases in temperature and internal energy can be observed in the coronal counterpart of the driven loop. With the presence of thermal conduction, chromospheric evaporation can also be seen. Although the volume averaged temperature and density changes seem slight ($\sim4\%$ relative to a non-driven loop), the enthalpy flow from the lower atmosphere redistributes the density and temperature in the vertical direction, thus enhancing the dissipation of wave energy in the corona. The efficient heating in the coronal counterpart of the loop can complement the thermal conductive losses shown in the current model and thus maintain the internal energy in the corona.

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M. Guo, T. Duckenfield, T. Doorsselaere, et. al.
Mon, 8 May 23
48/63

Comments: Accepted for publication in ApJL

Present and future constraints on flavor-dependent long-range interactions of high-energy astrophysical neutrinos [CL]

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http://arxiv.org/abs/2305.03675


The discovery of new, flavor-dependent neutrino interactions would provide compelling evidence of physics beyond the Standard Model. We focus on interactions generated by the anomaly-free, gauged, abelian lepton-number symmetries, specifically $L_e-L_\mu$, $L_e-L_\tau$, and $L_\mu-L_\tau$, that introduce a new matter potential sourced by electrons and neutrons, potentially impacting neutrino flavor oscillations. We revisit, revamp, and improve the constraints on these interactions that can be placed via the flavor composition of the diffuse flux of high-energy astrophysical neutrinos, with TeV-PeV energies, i.e., the proportion of $\nu_e$, $\nu_\mu$, and $\nu_\tau$ in the flux. Because we consider mediators of these new interactions to be ultra-light, lighter than $10^{-10}$ eV, the interaction range is ultra-long, from km to Gpc, allowing vast numbers of electrons and neutrons in celestial bodies and the cosmological matter distribution to contribute to this new potential. We leverage the present-day and future sensitivity of high-energy neutrino telescopes and of oscillation experiments to estimate the constraints that could be placed on the coupling strength of these interactions. We find that, already today, the IceCube neutrino telescope demonstrates potential to constrain flavor-dependent long-range interactions significantly better than existing constraints, motivating further analysis. We also estimate the improvement in the sensitivity due to the next-generation neutrino telescopes such as IceCube-Gen2, Baikal-GVD, KM3NeT, P-ONE, and TAMBO.

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S. Agarwalla, M. Bustamante, S. Das, et. al.
Mon, 8 May 23
49/63

Comments: 46 pages, 17 figures, 2 tables, 6 appendices. Comments are welcome

Peering into the central region of a nano-quasar: XMM-Newton and Chandra views of the CH Cyg Symbiotic System [HEAP]

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http://arxiv.org/abs/2305.03679


We present the analysis of archival XMM-Newton and Chandra observations of CH Cyg, one of the most studied symbiotic stars (SySts). The combination of the high-resolution XMM-Newton RGS and Chandra HETG X-ray spectra allowed us to obtain reliable estimates of the chemical abundances and to corroborate the presence of multi-temperature X-ray-emitting gas. Spectral fitting of the medium-resolution XMM-Newton MOS (MOS1+MOS2) spectrum required the use of an additional component not seen in previous studies in order to fit the 2.0-4.0 keV energy range. Detailed spectral modelling of the XMM-Newton MOS data suggests the presence of a reflection component, very similar to that found in active galactic nuclei. The reflection component is very likely produced by an ionised disk (the accretion disk around the white dwarf) and naturally explains the presence of the fluorescent Fe emission line at 6.4 keV while also contributing to the soft and medium energy ranges. The variability of the global X-ray properties of CH Cyg are discussed as well as the variation of the three Fe lines around the 6-7 keV energy range. We conclude that reflection components are needed to model the hard X-ray emission and may be present in most $\beta/\delta$-type SySt.

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J. Toalá, O. González-Martín, M. Karovska, et. al.
Mon, 8 May 23
50/63

Comments: 12 pages, 7 figures, 5 tables; To appear in MNRAS

ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H$_2$O and OH lines [SSA]

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http://arxiv.org/abs/2305.03171


Water and the hydroxyl radical are major constituents of the envelope of O-rich late-type stars. Transitions involving energy levels that are highly excited have been observed in both H$2$O and OH. These and more recently discovered transitions can now be observed at a high sensitivity and angular resolution with the ALMA Array. Spectra and maps of H$_2$O and OH observed with an angular resolution of 20 to $\sim$200 mas were obtained at two epochs with the ALMA array. Observations with the Compact Array were also used to check for time variability of water transitions. Radiative transfer models of water were revisited to characterize masing conditions and up-to-date chemical models were used for comparison with our observations. Ten rotational transitions of H$_2$O with energies up to 9000 K were observed in various vibrational states. All but one are new detections in space, and from these we have derived accurate rest frequencies. Hyperfine split $\Lambda$-doubling transitions in v = 0, J = 27/2 and 29/2 levels of the $^2\Pi{3/2}$ state and, $J = 33/2$ and 35/2 of the $^2\Pi_{1/2}$ state of OH with excitation energies up to 8900 K were also observed. Four of these transitions are new detections in space. Combining our measurements with earlier observations of OH, the v = 0 and v = 1 $\Lambda$-doubling frequencies have been improved. Our H$_2$O maps show compact emission and extensions up to twelve stellar radii or more. The 268.149 GHz emission line of water in the v$_2$ = 2 state is time variable, tends to be masing with dominant radiative pumping, and is widely excited. The widespread but weaker 262.898 GHz water line in v$_2$ = 1 also shows signs of maser emission. Emission and absorption of both H$_2$O and OH reveal an infall of matter and complex kinematics influenced by binarity. From our observed column densities, we derived OH/H$_2$O abundance ratios in a few stars.

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A. Baudry, K. Wong, S. Etoka, et. al.
Mon, 8 May 23
51/63

Comments: 41 pages with references and 25 figures in main text. 4 Tables in Appendix A. 10 figures in Appendix B. 2 figures in Appendix C. 14 figures in Appendix D. 5 figures in Appendix E. 2 figures in Appendix F

Detecting ALP wiggles at TeV energies [CL]

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http://arxiv.org/abs/2305.03604


Axions and axion-like-particles (ALPs) are characterised by their two-photon coupling, which entails so-called photon-ALP oscillations as photons propagate through a magnetic field. These oscillations lead to distinctive signatures in the energy spectrum of high-energy photons from astrophysical sources, allowing one to probe the existence of ALPs. In particular, photon-ALP oscillations will induce energy dependent oscillatory features, or “ALP wiggles”, in the photon spectra. We propose to use the discrete power spectrum to search for ALP wiggles and present a model-independent statistical test. By using PKS 2155-304 as an example, we show that the method has the potential to significantly improve the experimental sensitivities for ALP wiggles. Moreover, we discuss how these sensitivities depend on the modelling of the magnetic field. We find that the use of realistic magnetic field models, due to their larger cosmic variance, substantially enhances detection prospects compared to the use of simplified models.

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M. Kachelriess and J. Tjemsland
Mon, 8 May 23
52/63

Comments: 21 pages, 9 figures

X-ray Studies of Blazar 1ES 1959+650 Using SWIFT & XMM-NEWTON Satellite [HEAP]

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http://arxiv.org/abs/2305.03246


High synchrotron energy peaked blazar 1ES 1959+650 is studied with Swift and XMM-Newton satellite in total 127 observations during the period June 2018-December 2020. We extensively studied its flux and spectral variability on intra-day and long-term timescales. Discrete correlation function analysis between soft and hard X-ray bands indicates soft as well as hard lags. The results are used to constrain the magnetic field of the emitting region which is found to be 0.64 (0.05) Gauss. On long-term timescales, distribution of fluxes shows lognormality behaviour which could be attributed to minijets-in-a-jet model or might be due to the propagation of relativistic shocks down the jet. The spectral energy distribution around the synchrotron peak is well described by the log parabola model. Spectral parameters like peak energy E${p}$, curvature $\beta$ and the peak luminosity L${p}$ are derived from spectral analysis. Their correlations are studied to constrain the acceleration processes of the emitting particles. E${p}$ shows strong correlation with L${p}$ during the high state of the source which indicates spectral changes might be caused by the variations of the average electron energy. Low values of curvature parameter $\beta$ and a weak correlation between E$_{p}$ and ${\beta}$ indicates co-existence of stochastic/statistical acceleration of electrons in the emitting region. Implications of other results are also discussed.

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K. Wani, H. Gaur and M. Patil
Mon, 8 May 23
53/63

Comments: 14 pages, 6 figures, Accepted for publication in ApJ

Nonparametric model for the equations of state of neutron star from deep neural network [CL]

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http://arxiv.org/abs/2305.03323


It is of great interest to understand the equation of state (EOS) of the neutron star (NS), whose core includes highly dense matter. However, there are large uncertainties in the theoretical predictions for the EOS of NS. It is useful to develop a new framework, which is flexible enough to consider the systematic error in theoretical predictions and to use them as a best guess at the same time. We employ a deep neural network to perform a non-parametric fit of the EOS of NS using currently available data. In this framework, the Gaussian process is applied to represent the EOSs and the training set data required to close physical solutions. Our model is constructed under the assumption that the true EOS of NS is a perturbation of the relativistic mean-field model prediction. We fit the EOSs of NS using two different example datasets, which can satisfy the latest constraints from the massive neutron stars, NICER, and the gravitational wave of the binary neutron stars. Given our assumptions, we find that a maximum neutron star mass is $2.38^{+0.15}{-0.13} M\odot$ or $2.41^{+0.15}{-0.14}$ at $95\%$ confidence level from two different example datasets. It implies that the $1.4 M\odot$ radius is $12.31^{+0.29}{-0.31}$ km or $12.30^{+0.35}{-0.37}$ km. These results are consistent with results from previous studies using similar priors. It has demonstrated the recovery of the EOS of NS using a nonparametric model.

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W. Zhou, J. Hu, Y. Zhang, et. al.
Mon, 8 May 23
54/63

Comments: 12 pages, 9 figures, 2 tables, accepted by Astrophysical Journal

Large-Scale Ejecta of Z CMa — Proper Motion Study and New Features Discovered [SSA]

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http://arxiv.org/abs/2305.03080


Z Canis Majoris is a fascinating early-type binary with a Herbig Be primary and a FU Orionis-type secondary. Both of the stars exhibit sub-arcsecond jet-like ejecta. In addition, the primary is associated with the extended jet as well as with the large-scale outflow. In this study, we investigate further the nature of the large-scale outflow, which has not been studied since its discovery almost three and a half decades ago. We present proper motion measurements of individual features of the large-scale outflow and determine their kinematical ages. Furthermore, with our newly acquired deep images, we have discovered additional faint arc-shaped features that can be associated with the central binary.

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T. Liimets, M. Kraus, L. Cidale, et. al.
Mon, 8 May 23
55/63

Comments: 15 pages, 4 figures, published in Galaxies

Large-Scale Ejecta of Z CMa — Proper Motion Study and New Features Discovered [SSA]

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http://arxiv.org/abs/2305.03080


Z Canis Majoris is a fascinating early-type binary with a Herbig Be primary and a FU Orionis-type secondary. Both of the stars exhibit sub-arcsecond jet-like ejecta. In addition, the primary is associated with the extended jet as well as with the large-scale outflow. In this study, we investigate further the nature of the large-scale outflow, which has not been studied since its discovery almost three and a half decades ago. We present proper motion measurements of individual features of the large-scale outflow and determine their kinematical ages. Furthermore, with our newly acquired deep images, we have discovered additional faint arc-shaped features that can be associated with the central binary.

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T. Liimets, M. Kraus, L. Cidale, et. al.
Mon, 8 May 23
55/63

Comments: 15 pages, 4 figures, published in Galaxies

Posted in Uncategorized

Advances on the classification of radio image cubes [IMA]

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http://arxiv.org/abs/2305.03435


Modern radio telescopes will daily generate data sets on the scale of exabytes for systems like the Square Kilometre Array (SKA). Massive data sets are a source of unknown and rare astrophysical phenomena that lead to discoveries. Nonetheless, this is only plausible with the exploitation of intensive machine intelligence to complement human-aided and traditional statistical techniques. Recently, there has been a surge in scientific publications focusing on the use of artificial intelligence in radio astronomy, addressing challenges such as source extraction, morphological classification, and anomaly detection. This study presents a succinct, but comprehensive review of the application of machine intelligence techniques on radio images with emphasis on the morphological classification of radio galaxies. It aims to present a detailed synthesis of the relevant papers summarizing the literature based on data complexity, data pre-processing, and methodological novelty in radio astronomy. The rapid advancement and application of computer intelligence in radio astronomy has resulted in a revolution and a new paradigm shift in the automation of daunting data processes. However, the optimal exploitation of artificial intelligence in radio astronomy, calls for continued collaborative efforts in the creation of annotated data sets. Additionally, in order to quickly locate radio galaxies with similar or dissimilar physical characteristics, it is necessary to index the identified radio sources. Nonetheless, this issue has not been adequately addressed in the literature, making it an open area for further study.

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S. Ndung’u, T. Grobler, S. Wijnholds, et. al.
Mon, 8 May 23
56/63

Comments: 21 page review paper submitted to New astronomy reviews journal for review

A giant thin stellar stream in the Coma Galaxy Cluster [GA]

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http://arxiv.org/abs/2305.03073


The study of dynamically cold stellar streams reveals information about the gravitational potential where they reside and provides important constraints on dark matter properties. However, their intrinsic faintness makes detection beyond Local environments highly challenging. Here we report the detection of an extremely faint stellar stream (mu_g,max = 29.5 mag arcsec-2) with an extraordinarily coherent and thin morphology in the Coma Galaxy Cluster. This Giant Coma Stream spans 510 kpc in length and appears as a free-floating structure located at a projected distance of 0.8 Mpc from the center of Coma. We do not identify any potential galaxy remnant or core, and the stream structure appears featureless in our data. We interpret the Giant Coma Stream as being a recently accreted, tidally disrupting dwarf of M* ~ 10^8 Msun, and report a case with similar characteristics within the Illustris-TNG50 simulation. Our work shows the presence of free-floating, extremely faint and thin stellar streams in galaxy clusters, widening the environmental context for their promising future applications in the study of dark matter properties.

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J. Román, R. Rich, N. Ahvazi, et. al.
Mon, 8 May 23
57/63

Comments: Submitted to A&A. Comments welcome

The surprising evolution of the shadow on the TW Hya disk [SSA]

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http://arxiv.org/abs/2305.03611


We report new total intensity visible light high contrast imaging of the TW Hya disk taken with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST). This represents the first published images of the disk with STIS since 2016, when a moving shadow on the disk surface was reported. We continue to see the shadow moving in a counter-clockwise fashion, but in these new images the shadow has evolved into two separate shadows, implying a change in behavior for the occulting structure. Based on radiative transfer models of optically thick disk structures casting shadows, we infer that a plausible explanation for the change is that there are now two misaligned components of the inner disk. The first of these disks is located between 5-6au with an inclination of 5.5\arcdeg and PA of 170\arcdeg, the second between 6-7au with and inclination of 7\arcdeg and PA of 50\arcdeg. Finally, we speculate on the implications of the new shadow structure and determine that additional observations are needed to disentangle the nature of TW Hya’s inner disk architecture.

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J. Debes, R. Nealon, R. Alexander, et. al.
Mon, 8 May 23
58/63

Comments: 20 pages, 9 figures, published in ApJ

Unsigned magnetic flux proxy from solar optical intensity spectra [EPA]

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http://arxiv.org/abs/2305.03522


The photospheric unsigned magnetic flux has been shown to be highly correlated with radial velocity (RV) variations caused by solar surface activity. This activity indicator is therefore a prime candidate to unlock the potential of RV surveys to discover Earth twins orbiting Sun-like stars. We show for the first time how a precise proxy of the unsigned magnetic flux ($\Delta\alpha B^2$) can be obtained from Sun-as-a-star intensity spectra by harnessing the magnetic information contained in over 4000 absorption lines in the wavelength range from 380 to 690 nm. This novel activity proxy can thus be obtained from the same spectra from which RVs are routinely extracted. We derived $\Delta\alpha B^2$ from 500 randomly selected spectra from the HARPS-N public solar data set, which spans from 2015 to 2018. We compared our estimates with the unsigned magnetic flux values from the Solar Dynamics Observatory (SDO) finding excellent agreement (median absolute deviation: 4.9 per cent). The extracted indicator $\Delta\alpha B^2$ correlates with SDO’s unsigned magnetic flux estimates on the solar rotational timescale (Pearson correlation coefficient 0.67) and on the three-year timescale of our data set (correlation coefficient 0.91). We find correlations of $\Delta\alpha B^2$ with the HARPS-N solar RV variations of 0.49 on the rotational timescale and 0.78 on the three-year timescale. The Pearson correlation of $\Delta\alpha B^2$ with the RVs is found to be greater than the correlation of the classical activity indicators with the RVs. For solar-type stars, $\Delta\alpha B^2$ therefore represents the best simultaneous activity proxy known to date.

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F. Lienhard, A. Mortier, H. Cegla, et. al.
Mon, 8 May 23
59/63

Comments: 17 pages, 10 figures, accepted for publication in MNRAS

Constraining $f_{NL}$ using the Large-Scale Modulation of Small-Scale Statistics [CEA]

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http://arxiv.org/abs/2305.03070


We implement a novel formalism to constrain primordial non-Gaussianity of the local type from the large-scale modulation of the small-scale power spectrum. Our approach combines information about primordial non-Gaussianity contained in the squeezed bispectrum and the collapsed trispectrum of large-scale structure together in a computationally amenable and consistent way, while avoiding the need to model complicated covariances of higher $N$-point functions. This work generalizes our recent work, which used a neural network estimate of local power, to the more conventional local power spectrum statistics, and explores using both matter field and halo catalogues from the Quijote simulations. We find that higher $N$-point functions of the matter field can provide strong constraints on $f_{NL}$, but higher $N$-point functions of the halo field, at the halo density of Quijote, only marginally improve constraints from the two-point function.

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U. Giri, M. Münchmeyer and K. Smith
Mon, 8 May 23
60/63

Comments: 14 pages, 7 figures

Spectro-polarimetry at the Pic du Midi Turret Dome and new observations of the solar CaII K line [IMA]

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http://arxiv.org/abs/2305.03345


We summarize in this paper the spectro-polarimetric methods used at the Pic du Midi Turret Dome in spectroscopic or imagery mode. The polarimeters and spectrograph allow the cartography of solar magnetic fields at high spatial resolution through the Zeeman effect or measurements of the unresolved turbulent magnetic fields in the quiet Sun through the Hanle effect. We describe in this paper the optical capabilities of the successive versions of the polarimeters operating since 2003, and we present new results of magnetic field analysis with the CaII K 3933.7 {\AA} spectral line.

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J. Malherbe and T. Roudier
Mon, 8 May 23
61/63

Comments: N/A

The likelihood of the 21-cm power spectrum [CEA]

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http://arxiv.org/abs/2305.03074


Observations of the cosmic 21-cm power spectrum (PS) are starting to enable precision Bayesian inference of galaxy properties and physical cosmology, during the first billion years of our Universe. Here we investigate the impact of common approximations about the likelihood used in such inferences, including: (i) assuming a Gaussian functional form; (ii) estimating the mean from a single realization; and (iii) estimating the (co)variance at a single point in parameter space. We compare “classical” inference that uses an explicit likelihood with simulation based inference (SBI) that estimates the likelihood from a training set. Our forward-models include: (i) realizations of the cosmic 21-cm signal computed with 21cmFAST by varying UV and X-ray galaxy parameters together with the initial conditions; (ii) realizations of the telescope noise corresponding to a 1000 h integration with SKA1-Low; (iii) the excision of Fourier modes corresponding to a foreground-dominated, horizon “wedge”. We find that the 1D PS likelihood is well described by a Gaussian accounting for covariances between wavemodes and redshift bins (higher order correlations are small). However, common approaches of estimating the forward-modeled mean and (co)variance from a random realization or at a single point in parameter space result in biased and over-constrained posteriors. Our best results come from using SBI to fit a non-Gaussian likelihood with a Gaussian mixture neural density estimator. Such SBI can be performed with up to an order of magnitude fewer simulations than classical, explicit likelihood inference. Thus SBI provides accurate posteriors at a comparably low computational cost.

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D. Prelogović and A. Mesinger
Mon, 8 May 23
62/63

Comments: 16 pages, 12 figures, submitted to MNRAS

Tidally Heated Exomoons around $ε$ Eridani b: Observability and prospects for characterization [EPA]

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http://arxiv.org/abs/2305.03410


Exomoons are expected to orbit gas giant exoplanets just as moons orbit solar system planets. Tidal heating is present in solar system satellites and it can heat up their interior depending on their orbital and interior properties. We aim to identify a Tidally Heated Exomoon’s (THEM) orbital parameter space that would make it observable in infrared wavelengths with MIRI/JWST around $\epsilon$ Eridani b. We study the possible constraints on orbital eccentricity and interior properties that a successful THEM detection in infrared wavelengths can bring. We also investigate what exomoon properties need to be independently known in order to place these constraints. We use a coupled thermal-tidal model to find stable equilibrium points between the tidally produced heat and heat transported within a moon. For the latter, we consider a spherical and radially symmetric satellite with heat being transported via magma advection in a sub-layer of melt (asthenosphere) and convection in the lower mantle. We incorporate uncertainties in the interior and tidal model parameters to assess the fraction of simulated moons that would be observable with MIRI. We find that a $2 R_{Io}$ THEM orbiting $\epsilon$ Eridani b with an eccentricity of 0.02, would need to have a semi-major axis of 4 planetary Roche-radii for 100% of the simulations to produce an observable moon. These values are comparable with the orbital properties of gas giant solar system satellites. We place similar constraints for eccentricities up to 0.1. We conclude that if the semi-major axis and radius of the moon are known (eg. with exomoon transits), tidal dissipation can constrain the orbital eccentricity and interior properties of the satellite, such as the presence of melt and the thickness of the melt containing sub-layer.

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E. Kleisioti, D. Dirkx, M. Rovira-Navarro, et. al.
Mon, 8 May 23
63/63

Comments: N/A

Delensing of Cosmic Microwave Background Polarization with machine learning [CEA]

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http://arxiv.org/abs/2305.02490


Primordial B-mode detection is one of the main goals of next-generation cosmic microwave background (CMB) experiments. Primordial B-modes are a unique signature of primordial gravitational waves (PGWs). However, the gravitational interaction of CMB photons with large-scale structures will distort the primordial E modes, adding a lensing B-mode component to the primordial B-mode signal. Removing the lensing effect (`delensing’) from observed CMB polarization maps will be necessary to improve the constraint of PGWs and obtain a primordial E-mode signal. Here, we introduce a deep convolutional neural network model named multi-input multi-output U-net (MIMO-UNet) to perform CMB delensing. The networks are trained on simulated CMB maps with size $20^{\circ} \times 20^{\circ}$. We first use MIMO-UNet to reconstruct the unlensing CMB polarization ($Q$ and $U$) maps from observed CMB maps. The recovered E-mode power spectrum exhibits excellent agreement with the primordial EE power spectrum. The recovery of the primordial B-mode power spectrum for noise levels of 0, 1, and 2 $\mu$K-arcmin is greater than 98\% at the angular scale of $\ell<150$. We additionally reconstruct the lensing B map from observed CMB maps. The recovery of the lensing B-mode power spectrum is greater than roughly 99\% at the scales of $\ell>200$. We delens observed B-mode power spectrum by subtracting reconstructed lensing B-mode spectrum. The recovery of tensor B-mode power spectrum for noise levels of 0, 1, 2 $\mu$K-arcmin is greater than 98 \% at the angular scales of $\ell<120$. Even at $\ell=160$, the recovery of tensor B-mode power spectrum is still around 71 \%.

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Y. Yan, G. Wang, S. Li, et. al.
Fri, 5 May 23
1/67

Comments: 18 pages, 14 figures, 1 table, accepted by ApJS

Star Formation History of the Small Magellanic Cloud: the shell substructure [GA]

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http://arxiv.org/abs/2305.02755


We present the spatially resolved star formation history (SFH) of a shell-like structure located in the northeastern Small Magellanic Cloud (SMC). We quantitatively obtain the SFH using unprecedented deep photometric data (g~24 magnitude) from the SMASH survey and colour-magnitude diagram (CMD) fitting techniques. We consider, for the first time, the SMC’s line-of-sight depth and its optical effects on the CMDs. The SFH presents higher accuracy when a line-of-sight depth of ~3 Kpc is simulated. We find young star formation enhancements at ~150 Myr, ~200 Myr, ~450 Myr, ~650 Myr, and ~1 Gyr. Comparing the shell’s SFH with the Large Magellanic Cloud’s (LMC) northern arm SFH we show strong evidence of synchronicity from at least the past ~2.8 Gyr and, possibly, the past ~3.5 Gyr. Our results place constraints on the orbital history of the Magellanic Clouds which, potentially, have implications on their dynamical mass estimates.

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J. Sakowska, N. Noël, T. Ruiz-Lara, et. al.
Fri, 5 May 23
2/67

Comments: 4 pages, 3 figures. Submitted to the Proceedings of IAU Symposium 379: Dynamical Masses of Local Group Galaxies

Watersheds of the Universe: Laniakea and five newcomers in the neighborhood [CEA]

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http://arxiv.org/abs/2305.02339


This article delivers the dynamical cosmography of the Local Universe within z=0.1 (1 giga light-years). We exploit the gravitational velocity field computed using the CosmicFlows-4 catalog of galaxy distances to delineate superclusters as watersheds, publishing for the first time their size, shape, main streams of matter and the location of their central attractor. Laniakea, our home supercluster’s size is confirmed to be 2 $\times 10^6$ (Mpc $h^{-1}$)$^3$. Five more superclusters are now dynamically revealed in the same way: Apus, Hercules, Lepus, Perseus-Pisces and Shapley. Also, the central repellers of the Bootes and Sculptor voids are found and the Dipole and Cold Spot repellers now appear as a single gigantic entity. Interestingly the observed superclusters are an order of magnitude larger than the theoretical ones predicted by cosmological $\Lambda$CDM simulations.

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A. Dupuy and H. Courtois
Fri, 5 May 23
3/67

Comments: 8 pages, 4 figures, 1 table, submitted to A&A (AA/2023/46802)

On the growth of supermassive black holes formed from the gravitational collapse of fermionic dark matter cores [CEA]

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http://arxiv.org/abs/2305.02430


Observations support the idea that supermassive black holes (SMBHs) power the emission at the center of active galaxies. However, contrary to stellar-mass BHs, there is a poor understanding of their origin and physical formation channel. In this article, we propose a new process of SMBH formation in the early Universe that is not associated with baryonic matter (massive stars) or primordial cosmology. In this novel approach, SMBH seeds originate from the gravitational collapse of fermionic dense dark matter (DM) cores that arise at the center of DM halos as they form. We show that such a DM formation channel can occur before star formation, leading to heavier BH seeds than standard baryonic channels. The SMBH seeds subsequently grow by accretion. We compute the evolution of the mass and angular momentum of the BH using a geodesic general relativistic disk accretion model. We show that these SMBH seeds grow to $\sim 10^9$-$10^{10} M_\odot$ in the first Gyr of the lifetime of the Universe without invoking unrealistic (or fine-tuned) accretion rates.

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C. Argüelles, K. Boshkayev, A. Krut, et. al.
Fri, 5 May 23
4/67

Comments: 11 pages, 9 figures, 2 appendices. Accepted for publication in MNRAS

Snapshot Averaged Matrix Pencil Method (SAM) For Direction of Arrival Estimation [IMA]

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http://arxiv.org/abs/2305.02617


The estimation of the direction of electromagnetic (EM) waves from a radio source using electrically short antennas is one of the challenging problems in the field of radio astronomy. In this paper we have developed an algorithm which performs better in direction and polarization estimations than the existing algorithms. Our proposed algorithm Snapshot Averaged Matrix Pencil Method (SAM) is a modification to the existing Matrix Pencil Method (MPM) based Direction of Arrival (DoA) algorithm. In general, MPM estimates DoA of the incoherent EM waves in the spectra using unitary transformations and least square method (LSM). Our proposed SAM modification is made in context to the proposed Space Electric and Magnetic Sensor (SEAMS) mission to study the radio universe below 16 MHz. SAM introduces a snapshot averaging method to improve the incoherent frequency estimation improving the accuracy of estimation. It can also detect polarization to differentiate between Right Hand Circular Polarlization (RHCP), Right Hand Elliptical Polarlization (RHEP), Left Hand Circular Polarlization (LHCP), Left Hand Elliptical Polarlization (LHEP) and Linear Polarlization (LP). This paper discusses the formalism of SAM and shows the initial results of a scaled version of a DoA experiment at a resonant frequency of ~72 MHz.

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H. Tanti, A. Datta and S. Ananthakrishnan
Fri, 5 May 23
5/67

Comments: N/A

Untying the growth index to relief the $σ_8$ discomfort [CEA]

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http://arxiv.org/abs/2305.02863


The fluctuation of matter parameter $\sigma_8$ is by model construction degenerate with the growth index $\gamma$. Here we try to study the effect on the cosmological parameters constraints from treating each independently by considering $\sigma_8$ as a free and not derived parameter along with $\gamma$, to then try to constrain all by three probes, namely the CMB spectrum, the growth measurements from redshift space distortions $f\sigma_8$ and the galaxy cluster counts. We also want to asses the impact of this relaxation on the $\sigma_8$ tension. We also propose a more sophisticated correction, along with the classical one that takes into account the impact of cosmology on the growth measurements, which is to adjust the growth to keep the observed power spectrum invariant with the background evolution. We found that untying the two parameters does not shift the maximum likelihood on either $\sigma_8$ or $\gamma$ but rather allow for larger bounds with respect to when $\sigma_8$ is a derived parameter. More precisely, we obtain $\sigma_8 = 0.809\pm 0.043 $ and $\gamma = 0.613\pm 0.046$ in agreement with Planck constraints for the former and compatible with $\Lambda$CDM for the latter but with bounds enough wide to accomodate both values subject of tensions for $\sigma_8$. On the other hand, considering a tier correction yields $\sigma_8 = 0.734\pm 0.013$ close to the local values albeit with a growth index $\gamma = 0.636\pm 0.022$ while allowing a massive neutrinos yielded $\sigma_8 = 0.756\pm 0.024$, still preferring low values but with looser constraints, with $\gamma = 0.549\pm 0.048$ and a slight preference for $\Sigma m_\nu \sim 0.19$ value. We conclude that untying $\sigma_8$ and $\gamma$ helps in relieving the discomfort on the former between CMB and local probes and that careful analyse should be followed when using data obtained in a model dependent way.(abridged)

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Z. Sakr
Fri, 5 May 23
6/67

Comments: Prepared for a contribution to the special issue on Modified Gravity Approaches to the Tensions of {\Lambda}CDM

High-Energy Radiation and Ion Acceleration in Three-dimensional Relativistic Magnetic Reconnection with Strong Synchrotron Cooling [HEAP]

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http://arxiv.org/abs/2305.02348


We present the results of 3D particle-in-cell (PIC) simulations that explore relativistic magnetic reconnection in pair plasma with strong synchrotron cooling and a small mass fraction of non-radiating ions. Our results demonstrate that the structure of the current sheet is highly sensitive to the dynamic efficiency of radiative cooling. Specifically, stronger cooling leads to more significant compression of the plasma and magnetic field within the plasmoids. We demonstrate that ions can be efficiently accelerated to energies exceeding the plasma magnetization parameter, $\gg\sigma$, and form a hard power-law energy distribution, $f_i\propto \gamma^{-1}$. This conclusion implies a highly efficient proton acceleration in the magnetospheres of young pulsars. Conversely, the energies of pairs are limited to either $\sigma$ in the strong cooling regime or the radiation burnoff limit, $\gamma_{\rm syn}$, when cooling is weak. We find that the high-energy radiation from pairs above the synchrotron burnoff limit, $\varepsilon_c \approx 16$ MeV, is only efficiently produced in the strong cooling regime, $\gamma_{\rm syn} < \sigma$. In this regime, we find that the spectral cutoff scales as $\varepsilon_{\rm cut}\approx \varepsilon_c (\sigma/\gamma_{\rm syn})$, and the highest energy photons are beamed along the direction of the upstream magnetic field, consistent with the phenomenological models of gamma-ray emission from young pulsars. Furthermore, our results place constraints on the reconnection-driven models of gamma-ray flares in the Crab Nebula.

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A. Chernoglazov, H. Hakobyan and A. Philippov
Fri, 5 May 23
7/67

Comments: 24 pages, 18 figures, 1 table; Submitted to ApJ

Dissipative Genesis of the Inflationary Universe [CL]

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http://arxiv.org/abs/2305.02366


We study an inflation model with a flat scalar potential supported by observations and find that slow-roll inflation can emerge after a quasi-cyclic phase of the Universe, where it undergoes repeated expansions and contractions for a finite time period. The initial conditions and the positive spatial curvature required for such nontrivial dynamics align with the quantum creation of the Universe. The key ingredients that trigger inflation are dissipative interactions of the inflaton, which are necessary to reheat the Universe after inflation and thus give us an observational handle on pre-inflationary physics. Our discovery implies that inflation occurs more robustly after the creation.

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H. Matsui, A. Papageorgiou, F. Takahashi, et. al.
Fri, 5 May 23
8/67

Comments: 5 pages, 1 figure

Three-dimensional orbit of AC Her determined: Binary-induced truncation cannot explain the large cavity in this post-AGB transition disk [EPA]

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http://arxiv.org/abs/2305.02408


Some evolved binaries, namely post-asymptotic giant branch binaries, are surrounded by stable and massive circumbinary disks similar to protoplanetary disks found around young stars. Around 10% of these disks are transition disks: they have a large inner cavity in the dust. Previous interferometric measurements and modeling have ruled out the cavity being formed by dust sublimation and suggested that the cavity is due to a massive circumbinary planet that traps the dust in the disk and produces the observed depletion of refractory elements on the surface of the post-AGB star. In this study, we test alternative scenario in which the large cavity could be due to dynamical truncation from the inner binary. We performed near-infrared interferometric observations with the CHARA Array on the archetype of such a transition disk around a post-AGB binary: AC Her. We detect the companion at ten epochs over 4 years and determine the 3-dimensional orbit using these astrometric measurements in combination with the radial velocity time series. This is the first astrometric orbit constructed for a post-AGB binary system. We derive the best-fit orbit with a semi-major axis $2.01 \pm 0.01$ mas ($2.83\pm0.08$ au), inclination $(142.9 \pm 1.1)^\circ$ and longitude of the ascending node $(155.1 \pm 1.8)^\circ$. We find that the theoretical dynamical truncation and dust sublimation radius are at least $\sim3\times$ smaller than the observed inner disk radius ($\sim21.5$ mas or 30 au). This strengthens the hypothesis that the origin of such a cavity is due to the presence of a circumbinary planet.

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N. Anugu, J. Kluska, T. Gardner, et. al.
Fri, 5 May 23
9/67

Comments: Accepted to be published in The Astrophysical Journal

The edge-on protoplanetary disk HH 48 NE I. Modeling the geometry and stellar parameters [EPA]

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http://arxiv.org/abs/2305.02338


Context. Observations of edge-on disks are an important tool for constraining general protoplanetary disk properties that cannot be determined in any other way. However, most radiative transfer models cannot simultaneously reproduce the spectral energy distributions (SEDs) and resolved scattered light and submillimeter observations of these systems, due to the differences in geometry and dust properties at different wavelengths. Aims. We simultaneously constrain the geometry of the edge-on protoplanetary disk HH 48 NE and the characteristics of the host star. HH 48 NE is part of the JWST early release science program Ice Age. This work serves as a stepping stone towards a better understanding of the disk physical structure and icy chemistry in this particular source. This kind of modeling lays the groundwork for studying other edge-on sources to be observed with the JWST. Methods. We fit a parameterized dust model to HH 48 NE by coupling the radiative transfer code RADMC-3D and an MCMC framework. The dust structure was fitted independently to a compiled SED, a scattered light image at 0.8 ${\mu}$m and an ALMA dust continuum observation at 890 ${\mu}$m. Results. We find that 90% of the dust mass in HH 48 NE is settled to the disk midplane, less than in average disks, and that the atmospheric layers of the disk contain exclusively large grains (0.3-10 ${\mu}$m). The exclusion of small grains in the upper atmosphere likely has important consequences for the chemistry due to the deep penetration of high-energy photons. The addition of a relatively large cavity (ca. 50 au in radius) is necessary to explain the strong mid-infrared emission, and to fit the scattered light and continuum observations simultaneously.

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J. Sturm, M. McClure, C. Law, et. al.
Fri, 5 May 23
10/67

Comments: 16 pages, 8 figures, accepted for publication in Astronomy & Astrophysics

Small-scale dynamos: From idealized models to solar and stellar applications [SSA]

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http://arxiv.org/abs/2305.02787


In this article we review small-scale dynamo processes that are responsible for magnetic field generation on scales comparable to and smaller than the energy carrying scales of turbulence. We provide a review of critical observation of quiet Sun magnetism, which have provided strong support for the operation of a small-scale dynamo in the solar photosphere and convection zone. After a review of basic concepts we focus on numerical studies of kinematic growth and non-linear saturation in idealized setups, with special emphasis on the role of the magnetic Prandtl number for dynamo onset and saturation. Moving towards astrophysical applications we review convective dynamo setups that focus on the deep convection zone and the photospheres of solar-like stars. We review the critical ingredients for stellar convection setups and discuss their application to the Sun and solar-like stars including comparison against available observations.

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M. Rempel, T. Bhatia, L. Rubio, et. al.
Fri, 5 May 23
11/67

Comments: 54 pages, 10 figures, submitted to Space Science Reviews

Over-massive Central Black Holes in the Cosmological Simulations ASTRID and Illustris TNG50 [GA]

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http://arxiv.org/abs/2305.02335


Recent dynamical measurements indicate the presence of a central SMBH with mass $\sim 3\times 10^6 \, \rm M_\odot$ in the dwarf galaxy Leo I, placing the system $\sim50$ times above the standard, local $M_{BH} – M_\star$ relation. While a few over-massive central SMBHs are reported in nearby isolated galaxies, this is the first detected in a Milky Way satellite. We used the ASTRID and Illustris TNG50 LCDM cosmological simulations to investigate the assembly history of galaxies hosting over-massive SMBHs. We estimate that, at the stellar mass of Leo I, $\sim15\%$ of galaxies above the $M_{BH} – M_\star$ relation lie $>10$ times above it. Leo I-like systems are rare but exist in LCDM simulations: they occur in $\sim0.005\%$ of all over-massive systems. Examining the properties of simulated galaxies harboring over-massive central SMBHs, we find that: (i) stars assemble more slowly in galaxies above the $M_{BH} – M_\star$ relation; (ii) the gas fraction in these galaxies experiences a significantly steeper decline over time; and (iii) $>95\%$ of satellite host galaxies in over-dense regions are located above the $M_{BH} – M_\star$ relation. This suggests that massive satellite infall and consequent tidal stripping in a group/dense environment can drive systems away from the $M_{BH} – M_\star$ relation, causing them to become over-massive. As the merging histories of over-massive and under-massive systems do not differ, we conclude that additional environmental effects, such as being in overdense regions, must play a crucial role. In the high-$z$ Universe, central over-massive SMBHs are a signature of heavy black hole seeds; we demonstrate, in contrast, that low-$z$ over-massive systems result from complex environmental interactions.

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E. Weller, F. Pacucci, P. Natarajan, et. al.
Fri, 5 May 23
12/67

Comments: Accepted for publication in MNRAS. 9 pages, 8 figures

Gravitational Lensing of Gravitational Waves: Probing Intermediate Mass Black Holes in Galaxy Lenses with Global Minima [CEA]

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http://arxiv.org/abs/2305.02880


In this work, we study microlensing effects in strongly lensed gravitational wave (GW) signals corresponding to global minima in galaxy-scale lenses. We find that stellar microlenses alone are unable to introduce noticeable wave effects in the global minima GW signals at strong lensing magnification $(\mu)<50$ with match value between unlensed and lensed GW signals being above ${\sim}99.5\%$ in ${\sim}90\%$ of systems. Since the stellar microlenses introduce negligible wave effects in global minima, they can be used to probe the intermediate-mass black hole (IMBH) lenses in the galaxy lens. We show that the presence of an IMBH lens with mass in the range $[50,10^3]~{\rm M_\odot}$ such that the global minima lies within five Einstein radius of it, the microlensing effects at $f<10^2$ Hz are mainly determined by the IMBH lens for $\mu<50$. Assuming that a typical strong lensing magnification of 3.8 and high enough signal-to-noise ratio (in the range $\sim[10, 30]$) to detect the microlensing effect in GW signals corresponding to global minima, with non-detection of microlensing effects in ${\sim}15 ({\sim}150)$ lensed GW signals, we can rule out dark matter fraction $>10\% (>1\%)$ made of IMBH population inside galaxy lenses in mass range $[50, 10^3] {\rm M_\odot}$ with ${\sim}$90\% confidence.

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A. Meena
Fri, 5 May 23
13/67

Comments: 8 pages, 5 figures. Comments welcome

VERITAS discovery of very high energy gamma-ray emission from S3 1227+25 and multiwavelength observations [HEAP]

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http://arxiv.org/abs/2305.02860


We report the detection of very high energy gamma-ray emission from the blazar S3 1227+25 (VER J1230+253) with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). VERITAS observations of the source were triggered by the detection of a hard-spectrum GeV flare on May 15, 2015 with the Fermi-Large Area Telescope (LAT). A combined five-hour VERITAS exposure on May 16th and May 18th resulted in a strong 13$\sigma$ detection with a differential photon spectral index, $\Gamma$ = 3.8 $\pm$ 0.4, and a flux level at 9% of the Crab Nebula above 120 GeV. This also triggered target of opportunity observations with Swift, optical photometry, polarimetry and radio measurements, also presented in this work, in addition to the VERITAS and Fermi-LAT data. A temporal analysis of the gamma-ray flux during this period finds evidence of a shortest variability timescale of $\tau_{obs}$ = 6.2 $\pm$ 0.9 hours, indicating emission from compact regions within the jet, and the combined gamma-ray spectrum shows no strong evidence of a spectral cut-off. An investigation into correlations between the multiwavelength observations found evidence of optical and gamma-ray correlations, suggesting a single-zone model of emission. Finally, the multiwavelength spectral energy distribution is well described by a simple one-zone leptonic synchrotron self-Compton radiation model.

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A. Acharyya, C. Adams, A. Archer, et. al.
Fri, 5 May 23
14/67

Comments: 18 pages, 6 figures. Accepted for publication in the Astrophysical Journal (ApJ)

Evidence of First Stars-enriched Gas in High-redshift Absorbers [GA]

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http://arxiv.org/abs/2305.02346


The first stars were born from chemically pristine gas. They were likely massive, and thus they rapidly exploded as supernovae, enriching the surrounding gas with the first heavy elements. In the Local Group, the chemical signatures of the first stellar population were identified among low-mass, long-lived, very metal-poor ([Fe/H]<-2) stars, characterized by high abundances of carbon over iron ([C/Fe]>+0.7): the so-called carbon-enhanced metal-poor stars. Conversely, a similar carbon excess caused by first-star pollution was not found in dense neutral gas traced by absorption systems at different cosmic time. Here we present the detection of 14 very metal-poor, optically thick absorbers at redshift z~3-4. Among these, 3 are carbon-enhanced and reveal an overabundance with respect to Fe of all the analyzed chemical elements (O, Mg, Al, and Si). Their relative abundances show a distribution with respect to [Fe/H] that is in very good agreement with those observed in nearby very metal-poor stars. All the tests we performed support the idea that these C-rich absorbers preserve the chemical yields of the first stars. Our new findings suggest that the first-star signatures can survive in optically thick but relatively diffuse absorbers, which are not sufficiently dense to sustain star formation and hence are not dominated by the chemical products of normal stars.

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A. Saccardi, S. Salvadori, V. D’Odorico, et. al.
Fri, 5 May 23
15/67

Comments: N/A

Dynamical hotness, star formation quenching and growth of supermassive black holes [GA]

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http://arxiv.org/abs/2305.02910


A stellar system is dynamically hot when its kinetic energy is dominated by random motion represented by the velocity dispersion $\sigma_{\rm hot} (M_*)$. We use MaNGA data to obtain inner and outer dispersion of a galaxy, $\sigma_{\rm in}$ and $\sigma_{\rm out}$, to characterize its dynamical status and study its connection with star formation quenching and the growth of supermassive black hole (SMBH). We divide galaxies into fully quenched (FQGs), partially quenched (PQGs) and fully star-forming (FSGs) populations, and identify quenched central cores (QCCs) in PQGs. The galaxy distribution in $\sigma_{\rm in}/\sigma_{\rm hot}$-$\sigma_{\rm out}/\sigma_{\rm hot}$ diagram is L-shaped, consisting of a horizontal sequence ($\sigma_{\rm out}/\sigma_{\rm hot}\sim0$) and a vertical sequence ($\sigma_{\rm in}/\sigma_{\rm hot}\sim1$). FQGs and QCCs are located at the top of vertical sequence, $\sigma_{\rm out}/\sigma_{\rm hot}\sim1$, therefore they are dynamically hot over their entire bodies. PQGs reside along vertical sequence, so they have hot center but cold outskirt. FSGs are diverse and can be found in both sequences. Galaxy structural properties, star formation and AGN activities make a transition along horizontal sequence at $\log(\sigma_{\rm in}/\sigma_{\rm hot})\sim-0.3$, and along vertical sequence at $\log(\sigma_{\rm out}/\sigma_{\rm hot})\sim-0.3$. The fractions of optical AGNs and barred galaxies increase rapidly in the first transition and decline rapidly in the second; radio galaxies are located at the top of vertical sequence. Our results demonstrate that star formation quenching and SMBH growth are effective only in dynamically hot systems. A simple model along this line can reproduce the observed SMBH scaling relations. We discuss how secular processes and strong interactions can make a system dynamically hot, and lead to the SMBH growth and star formation quenching.

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H. Hong, H. Wang, H. Mo, et. al.
Fri, 5 May 23
16/67

Comments: 24 pages, 19 figures, submitted to ApJ

Extensions to $Λ$CDM at Intermediate Redshifts to Solve the Tensions ? [CEA]

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http://arxiv.org/abs/2305.02913


Models of dark energy or modified gravity that tries to alleviate the tensions on the Hubble constant ($H_0$) and the matter fluctuation parameter ($\sigma_8$) are usually parameterized as function of either late or early time cosmic evolution. In this work we rather focus on one that could privilege extensions to $\Lambda$CDM on intermediate redshifts by mean of a Gaussian-like window function with a free moving centre $a_{Gwin}$ combined with a modified gravity parameter $\mu_{Gwin}$ and an extension of the equation of state parameter $\omega_{Gwin}$. Using different combinations of the latest available current datasets subject of the discrepancies, such as the cosmic microwave (CMB) background power spectrum, the baryonic acoustic scale (BAO) in galaxy distribution, Weak lensing (WL) shear and galaxy clustering cross correlations and local hubble constant measurements, we investigate whether such model could alleviate each or both $H_0$ and $\sigma_8$ tensions. We found when combining all probes that the $\sigma_8$ tension is alleviated while the $H_0$ is reduced with a small preference for a positive $\omega_{Gwin}$ without a particular preference for a redshift or a $\mu_{Gwin}$ different from its equivalent $\Lambda$CDM value. However, if we follow another approach and compare the two sets of the probes subject of discrepancy i.e. CMB+BAO vs WL+local $H_0$, we found that the model is able of solving the $\sigma_8$ discrepancy at the expense of a enlargement of the constraints, while the Hubble constant discrepancy is not that affected due to the fact that the two likelihood contours are stretched in parallel directions. We conclude that modifying $\Lambda$CDM cosmology at intermediate redshifts within our model, and the constraints from the datasets used in this study, are not likely a viable solution to solve both tensions.

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Z. Sakr
Fri, 5 May 23
17/67

Comments: Prepared for proceedings of Corfu Summer Institute 2022 “School and Workshops on Elementary Particle Physics and Gravity”

Predicting Stellar Rotation Periods Using XGBoost [SSA]

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http://arxiv.org/abs/2305.02407


This work aims to develop a computationally inexpensive approach, based on machine learning techniques, to accurately predict thousands of stellar rotation periods. The innovation in our approach is the use of the XGBoost algorithm to predict the rotation periods of Kepler targets by means of regression analysis. Therefore, we focused on building a robust supervised machine learning model to predict surface stellar rotation periods from structured data sets built from the Kepler catalogue of K and M stars. We analysed the set of independent variables extracted from Kepler light curves and investigated the relationships between them and the ground truth. Using the extreme gradient boosting method, we obtained a minimal set of variables that can be used to build machine learning models for predicting stellar rotation periods. Our models are validated by predicting the rotation periods of about 2900 stars. The results are compatible with those obtained by classical techniques and comparable to those obtained by other recent machine learning approaches, with the advantage of using much fewer predictors. Restricting the analysis to stars with rotation periods of less than 45 days, our models are on average 95 to 98 % correct. We have developed an innovative approach, based on a machine learning method, to accurately fit the rotation periods of stars. Based on the results of this study, we conclude that the best models generated by the proposed methodology are competitive with the state-of-the-art approaches, with the advantage of being computationally cheaper, easy to train, and relying on small sets of predictors.

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N. Gomes, F. Sordo and L. Torgo
Fri, 5 May 23
18/67

Comments: Paper submitted to A&A. Comments are welcome!

Effect of Earth-Moon's gravity on TianQin's range acceleration noise. III. An analytical model [IMA]

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http://arxiv.org/abs/2305.02539


TianQin is a proposed space-based gravitational wave detector designed to operate in circular high Earth orbits. As a sequel to [Zhang et al. Phys. Rev. D 103, 062001 (2021)], this work provides an analytical model to account for the perturbing effect of the Earth’s gravity field on the range acceleration noise between two TianQin satellites. For such an “orbital noise,” the Earth’s contribution dominates above $5\times 10^{-5}$ Hz in the frequency spectrum, and the noise calibration and mitigation, if needed, can benefit from in-depth noise modeling. Our model derivation is based on Kaula’s theory of satellite gravimetry with Fourier-style decomposition, and uses circular reference orbits as an approximation. To validate the model, we compare the analytical and numerical results in two main scenarios. First, in the case of the Earth’s static gravity field, both noise spectra are shown to agree well with each other at various orbital inclinations and radii, confirming our previous numerical work while providing more insight. Second, the model is extended to incorporate the Earth’s time-variable gravity. Particularly relevant to TianQin, we augment the formulas to capture the disturbance from the Earth’s free oscillations triggered by earthquakes, of which the mode frequencies enter TianQin’s measurement band above 0.1 mHz. The analytical model may find applications in gravity environment monitoring and noise-reduction pipelines for TianQin.

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L. Jiao and X. Zhang
Fri, 5 May 23
19/67

Comments: 16 pages, 9 figures, accepted by Phys. Rev. D

On the propagation of gravity waves in the lower solar atmosphere in different magnetic configurations [SSA]

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http://arxiv.org/abs/2305.02740


Gravity waves are generated by turbulent subsurface convection overshooting or penetrating locally into a stably stratified medium. While propagating energy upwards, their characteristic negative phase shift over height is a well-recognized observational signature. Since their first detailed observational detection and estimates of energy content, a number of studies have explored their propagation characteristics and interaction with magnetic fields and other wave modes in the solar atmosphere. Here, we present a study of the atmospheric gravity wave dispersion diagrams utilizing intensity observations that cover photospheric to chromospheric heights over different magnetic configurations of quiet-Sun (magnetic network regions), a plage, and a sunspot as well as velocity observations within the photospheric layer over a quiet and a sunspot region. In order to investigate the propagation characteristics, we construct two-height intensity – intensity and velocity-velocity cross-spectra and study phase and coherence signals in the wavenumber-frequency dispersion diagrams and their association with background magnetic fields. We find signatures of association between magnetic fields and much reduced coherence and phase shifts over height from intensity-intensity and velocity-velocity phase and coherence diagrams, both indicating suppression/scattering of gravity waves by the magnetic fields. Our results are consistent with the earlier numerical simulations, which indicate that gravity waves are suppressed or scattered and reflected back into the lower solar atmosphere in the presence of magnetic fields.

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H. Kumar, B. Kumar and S. Rajaguru
Fri, 5 May 23
20/67

Comments: 19 pages, 19 Figures, Accepted for publication in Advances in Space Research journal

Disk-wind-driven Expanding Radio-emitting Shell in Tidal Disruption Events [HEAP]

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http://arxiv.org/abs/2305.02619


We study the evolution of a non-relativistically expanding thin shell in radio-emitting tidal disruption events (TDEs) based on a one-dimensional spherically symmetric model considering the effect of both a time-dependent mass loss rate of the disk wind and the ambient mass distribution. The analytical solutions are derived in two extreme limits: one is the approximate solution near the origin in the form of the Taylor series, and the other is the asymptotic solution in which the ambient matter is dominant far away from the origin. Our numerical solutions are confirmed to agree with the respective analytical solutions. We find that no simple power-law of time solution exists in early to middle times because the mass loss rate varies over time, affecting the shell dynamics. We also discuss the application of our model to the observed radio-emitting TDE, AT2019dsg.

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K. Hayasaki and R. Yamazaki
Fri, 5 May 23
21/67

Comments: 26 pages, 6 figures

Multi-Image X-ray Interferometer Module: I. design concept and proof-of-concept experiments with fine-pitch slits [IMA]

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http://arxiv.org/abs/2305.03050


We propose a novel x-ray imaging system, Multi-Image X-ray Interferometer Module (MIXIM), with which a very high angular resolution can be achieved even with a small system size. MIXIM is composed of equally-spaced multiple slits and an x-ray detector, and its angular resolution is inversely proportional to the distance between them. Here we report our evaluation experiments of MIXIM with a newly adopted CMOS sensor with a high spatial resolution of 2.5 {\mu}m. Our previous experiments with a prototype MIXIM were limited to one-dimensional imaging, and more importantly, the achieved angular resolution was only {\sim}1″, severely constrained due to the spatial resolution of the adopted sensor with a pixel size of 4.25 {\mu}m. By contrast, one-dimensional images obtained in this experiment had a higher angular resolution of 0.5″ when a configured system size was only {\sim}1 m, which demonstrates that MIXIM can simultaneously realize a high angular resolution and compact size. We also successfully obtained a two-dimensional profile of an x-ray beam for the first time for MIXIM by introducing a periodic pinhole mask. The highest angular resolution achieved in our experiments is smaller than 0.1″ with a mask-sensor distance of 866.5 cm, which shows the high scalability of MIXIM.

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K. Asakura, K. Hayashida, T. Kawabata, et. al.
Fri, 5 May 23
22/67

Comments: 33 pages, 14 figures, 2 tables, accepted for publication in JATIS

Galactic cosmic ray transport in the absence of resonant scattering [HEAP]

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http://arxiv.org/abs/2305.02890


Galactic cosmic ray transport relies on the existence of turbulence on scales comparable with the gyration radius of the particles and with wavenumber vector oriented along the local magnetic field. In the standard picture, in which turbulence is injected at large scales and cascades down to smaller scales, it is all but guaranteed that turbulence on the relevant scales may be present, either because of anisotropic cascading or because of the onset of damping processes. This raises questions on the nature of cosmic-ray scattering, especially at energies $\gtrsim 1$ TeV, where self-generation is hardly relevant. Here, by means of numerical simulations of charged test-particles in a prescribed magnetic field, we investigate particle diffusion in a situation in which turbulence is mainly present at large scales, with the possible presence of a smaller power on small scales, and discuss possible implications of this setup for cosmic-ray transport phenomenology.

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O. Pezzi and P. Blasi
Fri, 5 May 23
23/67

Comments: 5 pages, submitted to MNRAS Letters

Multiplicity Boost Of Transit Signal Classifiers: Validation of 69 New Exoplanets Using The Multiplicity Boost of ExoMiner [EPA]

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http://arxiv.org/abs/2305.02470


Most existing exoplanets are discovered using validation techniques rather than being confirmed by complementary observations. These techniques generate a score that is typically the probability of the transit signal being an exoplanet (y(x)=exoplanet) given some information related to that signal (represented by x). Except for the validation technique in Rowe et al. (2014) that uses multiplicity information to generate these probability scores, the existing validation techniques ignore the multiplicity boost information. In this work, we introduce a framework with the following premise: given an existing transit signal vetter (classifier), improve its performance using multiplicity information. We apply this framework to several existing classifiers, which include vespa (Morton et al. 2016), Robovetter (Coughlin et al. 2017), AstroNet (Shallue & Vanderburg 2018), ExoNet (Ansdel et al. 2018), GPC and RFC (Armstrong et al. 2020), and ExoMiner (Valizadegan et al. 2022), to support our claim that this framework is able to improve the performance of a given classifier. We then use the proposed multiplicity boost framework for ExoMiner V1.2, which addresses some of the shortcomings of the original ExoMiner classifier (Valizadegan et al. 2022), and validate 69 new exoplanets for systems with multiple KOIs from the Kepler catalog.

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H. Valizadegan, M. Martinho, J. Jenkins, et. al.
Fri, 5 May 23
24/67

Comments: N/A

The edge-on protoplanetary disk HH 48 NE II. Modeling ices and silicates [EPA]

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http://arxiv.org/abs/2305.02355


The abundance and distribution of ice in protoplanetary disks (PPD) is critical to understand the linkage between the composition of circumstellar matter and the composition of exoplanets. Edge-on PPDs are a useful tool to constrain such ice composition and its location in the disk, as ice spectral signatures can be observed in absorption against the continuum emission arising from the warmer central disk regions. The aim of this work is to model ice absorption features in PPDs and determine how well the abundance of the main ice species across the disk can be determined within the uncertainty of the physical parameter space. The edge-on PPD around HH 48 NE, a target of the JWST ERS program IceAge, is used as a reference system. We use RADMC-3D to raytrace the mid-infrared continuum. Using a constant parameterized ice abundance, ice opacities are added to the dust opacity in regions wherever the disk is cold enough for the main carbon, oxygen and nitrogen carriers to freeze out. The global abundance of the main ice carriers in HH 48 NE can be determined within a factor of 3, when taking the uncertainty of the physical parameters into account. Ice features in PPDs can be saturated at an optical depth <1, due to local saturation. Spatially observed ice optical depths cannot be directly related to column densities due to radiative transfer effects. Vertical snowlines will not be a clear transition due to the radially increasing height of the snowsurface, but their location may be constrained from observations using radiative transfer modeling. Radial snowlines are not really accesible. Not only the ice abundance, but also inclination, settling, grain size distribution and disk mass have strong impact on the observed ice absorption features in disks. Relative changes in ice abundance can be inferred from observations only if the source structure is well constrained

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J. Sturm, M. McClure, J. Bergner, et. al.
Fri, 5 May 23
25/67

Comments: 18 pages, 12 figures, accepted for publication in Astronomy & Astrophysics

Cool Cores in Clusters of Galaxies in the Dark Energy Survey [CEA]

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http://arxiv.org/abs/2305.02365


We search for the presence of cool cores in optically-selected galaxy clusters from the Dark Energy Survey (DES) and investigate their prevalence as a function of redshift and cluster richness. Clusters were selected from the redMaPPer analysis of three years of DES observations that have archival Chandra X-ray observations, giving a sample of 99 clusters with a redshift range of $0.11 < z < 0.87$ and a richness range of $25 < \lambda < 207$. Using the X-ray data, the core temperature was compared to the outer temperature to identify clusters where the core temperature is a factor of 0.7 or less than the outer temperature. We found a cool core fraction of approximately 20% with no significant trend in the cool core fraction with either redshift or richness.

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K. Graham, J. O’Donnell, M. Silverstein, et. al.
Fri, 5 May 23
26/67

Comments: shortened version accepted to RNAAS

Variability of Young Stellar Objects in the Perseus Molecular Cloud [SSA]

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http://arxiv.org/abs/2305.02514


We present an analysis of 288 young stellar objects (YSOs) in the Perseus Molecular Cloud that have well defined $g$ and $r$-band lightcurves from the Zwicky Transient Facility. Of the 288 YSOs, 238 sources (83% of our working sample) are identified as variables based on the normalized peak-to-peak variability metric, with variability fraction of 92% for stars with disks and 77% for the diskless populations. These variables are classified into different categories using the quasiperiodicity ($Q$) and flux asymmetry ($M$) metrics. Fifty-three variables are classified as strictly periodic objects that are well phased and can be attributed to spot modulated stellar rotation. We also identify 22 bursters and 25 dippers, which can be attributed to accretion burst and variable extinction, respectively. YSOs with disks tend to have asymmetric and non-repeatable lightcurves, while the YSOs without disks tend to have (quasi)periodic lightcurves. The periodic variables have the steepest change in $g$ versus $g-r$, while bursters have much flatter changes than dippers in $g$ versus $g-r$. Periodic and quasiperiodic variables display the lowest variability amplitude. Simple models suggest that the variability amplitudes of periodic variables correspond to changes of the spot coverage of 30% to 40%, burster variables are attributed to accretion luminosity changes in the range of $L_{\rm acc}/L_{\star}=0.1-0.3$, and dippers are due to variable extinction with $A_{V}$ changes in the range of $0.5-1.3\;$mag.

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X. Wang, M. Fang, G. Herczeg, et. al.
Fri, 5 May 23
27/67

Comments: 26 pages, 16 figures, 3 tables, accepted for publication in RAA

HYPerluminous quasars at the Epoch of ReionizatION (HYPERION). A new regime for the X-ray nuclear properties of the first quasars [GA]

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http://arxiv.org/abs/2305.02347


The existence of luminous quasars (QSO) at the Epoch of Reionization (EoR; i.e. z>6) powered by supermassive black holes (SMBH) with masses $\gtrsim10^9~M_\odot$ challenges models of early SMBH formation. To shed light on the nature of these sources we started a multiwavelength programme based on a sample of 18 HYPerluminous quasars at the Epoch of ReionizatION (HYPERION). These are the luminous QSOs whose SMBH must have had the most rapid mass growth during the Universe first Gyr. In this paper we present the HYPERION sample and report on the first of the 3 years planned observations of the 2.4 Ms XMM-Newton Multi-Year Heritage programme on which HYPERION is based. The goal of this programme is to accurately characterise the X-ray nuclear properties of QSOs at the EoR. Through a joint X-ray spectral analysis of 10 sources, covering the rest-frame $\sim2-50$ keV range, we report a steep average photon index ($\Gamma\sim2.4\pm0.1$) which is inconsistent at $\geq4\sigma$ level with the value measured in QSO at z<6. This spectral slope is also significantly steeper than that reported in lower-z QSOs with similar luminosity or accretion rate, thus suggesting a genuine redshift evolution. Alternatively, we can interpret this result as the presence of an unusually low-energy cutoff $E_{cut}\sim20$ keV on a standard $\Gamma=1.9$ power-law. We also report on mild indications that HYPERION QSOs show higher soft X-ray emission at 2 keV compared to the UV one at 2500A than expected by lower-z luminous AGN. We speculate that a redshift-dependent coupling between the X-ray corona and accretion disc or intrinsically different coronal properties may account for the steep spectral slopes, especially in the presence of powerful winds. The reported slopes, if confirmed at lower luminosities, may have an important impact on the design of future X-ray facilities and surveys aimed at the early Universe.

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L. Zappacosta, E. Piconcelli, F. Fiore, et. al.
Fri, 5 May 23
28/67

Comments: 21 pages (including appendix), 12 figures, 4 tables. Submitted to A&A

The impact of effective matter mixing based on three-dimensional hydrodynamical models on the molecule formation in the ejecta of SN 1987A [HEAP]

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http://arxiv.org/abs/2305.02550


To investigate the impact of matter mixing on the formation of molecules in the ejecta of SN 1987A, time-dependent rate equations for chemical reactions are solved for one-zone and one-dimensional ejecta models of SN 1987A. The latter models are based on the one-dimensional profiles obtained by angle-averaging of the three-dimensional hydrodynamical models, which effectively reflect the 3D matter mixing; the impact is demonstrated, for the first time, based on three-dimensional hydrodynamical models. The distributions of initial seed atoms and radioactive $^{56}$Ni influenced by the mixing could affect the formation of molecules. By comparing the calculations for spherical cases and for several specified directions in the bipolar-like explosions in the three-dimensional hydrodynamical models, the impact is discussed. The decay of $^{56}$Ni, practically $^{56}$Co at later phases, could heat the gas and delay the molecule formation. Additionally, Compton electrons produced by the decay could ionize atoms and molecules and could destruct molecules. Several chemical reactions involved with ions such as H$^+$ and He$^+$ could also destruct molecules. The mixing of $^{56}$Ni plays a non-negligible role in both the formation and destruction of molecules through the processes above. The destructive processes of carbon monoxide and silicon monoxide due to the decay of $^{56}$Ni generally reduce the amounts. However, if the molecule formation is sufficiently delayed under a certain condition, the decay of $^{56}$Ni could increase the amounts through a sequence of passes instead compared with the case with lower efficiencies for the destructive processes above.

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M. Ono, T. Nozawa, S. Nagataki, et. al.
Fri, 5 May 23
29/67

Comments: 74 pages, 29 figures, 11 tables; submitted to ApJS

Rotating neutron stars in the first order post-Newtonian approximation [HEAP]

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http://arxiv.org/abs/2305.02413


We study models of uniformly and differentially rotating neutron stars in the framework of post-Newtonian approximation in general relativity as established by Chandrasechar. In particular, we adopt the polytropic equation of state in order to derive the appropriate hydrodynamic equations and a rotation law based on the generalized Clement’s model. To compute equilibrium configurations at the mass-shedding limit, i.e. at critical angular velocity (equivalently, Keplerian angular velocity), we develop an iterative numerical method, belonging to the category of the well-known self-consistent field methods'', with two perturbation parameters: therotation parameter” $\bar{\upsilon}$ and the “gravitation or relativity parameter” $\bar{\sigma}$. These two parameters represent the effects of rotation and gravity on the configuration. We investigate the validity and the limits of our method by comparing our results with respective results of other computational methods and public domain codes. As it turns out, our method can derive satisfactory results for general-relativistic polytropic configurations at critical rotation.

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A. Fotopoulos, V. Karageorgopoulos and V. Geroyannis
Fri, 5 May 23
30/67

Comments: 28 pages, 6 Figures, 5 Tables, Submitted April 2023 Astronomy and Computing

Little Rip, Pseudo Rip and bounce cosmology from generalized equation of state in the Universe with spatial curvature [CL]

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http://arxiv.org/abs/2305.02796


We consider the Little Rip (LR), Pseudo Rip (PR) and bounce cosmological models in the Friedmann-Robertson-Walker (FRW) metric with nonzero spatial curvature. We describe the evolution of the universe using a generalized equation of state in the presence of a viscous fluid. The conditions of the occurrence of the LR, PR and bounce were obtained from the point of view of the parameters of the generalized equation of state for the cosmic dark fluid, taking into account the spatial curvature. The analytical expressions for the spatial curvature were obtained. Asymptotic cases of the early and late universe are considered. A method of Darboux transformation was proposed in the case of models of an accelerating universe with viscosity.

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A. A.V.Timoshkin and A. Yurov
Fri, 5 May 23
31/67

Comments: to appear in International Journal of Geometric Methods in Modern Physics

Bimodal black-hole mass distribution and chirp masses of binary black-hole mergers [HEAP]

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http://arxiv.org/abs/2305.02380


In binary black-hole mergers from isolated binary-star evolution, both black holes are from progenitor stars that have lost their hydrogen-rich envelopes by binary mass transfer. Envelope stripping is known to affect the pre-supernova core structures of such binary-stripped stars and thereby their final fates and compact remnant masses. In this paper, we show that binary-stripped stars give rise to a bimodal black-hole mass spectrum with characteristic black-hole masses of about $9\,\mathrm{M}\odot$ and $16\,\mathrm{M}\odot$ across a large range of metallicities. The bimodality is linked to carbon and neon burning becoming neutrino-dominated, which results in interior structures that are difficult to explode and likely lead to black hole formation. The characteristic black-hole masses from binary-stripped stars have corresponding features in the chirp-mass distribution of binary black-hole mergers: peaks at about $8$ and $14\,\mathrm{M}\odot$, and a dearth in between these masses. Current gravitational-wave observations of binary black-hole mergers show evidence for a gap at $10\text{–}12\,\mathrm{M}\odot$ and peaks at $8$ and $14\,\mathrm{M}_\odot$ in the chirp-mass distribution. These features are in agreement with our models of binary-stripped stars. In the future, they may be used to constrain the physics of late stellar evolution and supernova explosions, and may even help measure the cosmological expansion of the Universe.

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F. Schneider, P. Podsiadlowski and E. Laplace
Fri, 5 May 23
32/67

Comments: 20 pages (including appendix with tabulated data; main text: 8 pages), 6 figures; submitted to AAS journals

One matter density discrepancy to alleviate them all or further trouble for $Λ$CDM model [CEA]

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http://arxiv.org/abs/2305.02846


We investigate whether the two cosmological discrepancies on the Hubble constant ($H_0$) and the matter fluctuation parameter ($\sigma_8$) could be traded by only one on the present value of the matter density ($\Omega_{\rm{M}}$). We combined different probes in an agnostic approach by, either relaxing the calibration parameters in each probe in order to be set by the data, or by only including priors with the condition that they are obtained independently from the discrepant parameters. We also compiled and used a dataset from previous direct measurements of $\Omega_{\rm{M}}$. We found when combining, as our baseline, galaxy clusters counts + cluster baryon fraction probe + cosmic chronometers + direct $\Omega_{\rm{M}}$ + priors from BBN and CMB, that both parameters, $H_0$ and $\sigma_8$, are consistent with those inferred with local probes, with $\sigma_8 = 0.745 \pm 0.05$ while $H_0 = 73.8 \pm 3.01$, and that for a value of $\Omega_{\rm{M}} = 0.22 \pm 0.01$ at more than 3$\sigma$ from that usually determined by CMB. We also found similar preferences when replacing cosmic chronometers (CC) by the Supernovae (SN) data while allowing its calibration parameter to vary. However discrepancies appeared when we combined SN in addition to CC suggesting either inconsistencies between the SN sample and the other probes used or a serious challenge to our hypothesis. We conclude that, either reconciling both tensions requires local inferred values of matter density at odd with those obtained by CMB, reviving by then an overlooked discrepancy, or simply that further evidences are indicating that $\Lambda$CDM model is facing more difficulties to accommodate simultaneously all the current available observations.(abridged)

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Z. Sakr
Fri, 5 May 23
33/67

Comments: Comments and missing citation requests are welcomed. Abstract abridged for arxiv submission

Instabilities in dusty non-isothermal proto-planetary discs [EPA]

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http://arxiv.org/abs/2305.02362


Protoplanetary discs (PPDs) can host a number of instabilities that may partake directly or indirectly in the process of planetesimal formation. These include the Vertical Shear Instability (VSI), Convective Overstability (COS), Streaming Instability (SI), and Dust Settling Instability (DSI), to name a few. Notably, the VSI and COS have mostly been studied in purely gaseous discs, while the SI and DSI have only been analyzed in isothermal discs. How these instabilities operate under more general conditions is therefore unclear. To this end, we devise a local model of a PPD describing a non-isothermal gas interacting with a single species of dust via drag forces. Using this, we find that dust drag sets minimum length scales below which the VSI and COS are suppressed. Similarly, we find that the SI can be suppressed on sufficiently small scales by the gas’ radial buoyancy if it cools on roughly a dynamical timescale. We show that the DSI can be effectively stabilized by vertical buoyancy, except at special radial and vertical length scales. We also find novel instabilities unique to a dusty, non-isothermal gas. These result in a dusty analog of the COS that operates in slowly cooled discs, and a dusty version of the VSI that is strongly enhanced by dust settling. We briefly discuss the possible implications of our results on planetesimal formation.

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M. Lehmann and M. Lin
Fri, 5 May 23
34/67

Comments: 40 pages, 26 figures

Computed microwave spectra of C$_{70}^+$ [GA]

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http://arxiv.org/abs/2305.02331


The apolar fullerenes C60 and C70 are not accessible for radio astronomy. Upon ionization static Jahn-Teller effects occur in C70+ that distort the D5h neutral symmetry to Cs. This point group is polar thus ionization induces a permanent electric dipole moment in C70. The goal of the present calculations is to compute the equilibrium geometry and dipole moment of the C70+ cation by various DFT methods and to simulate microwave spectra. Using quantum chemistry rotational constants, Cartesian dipole moment components and the resultant dipole, as well as Jahn-Teller stabilization energies and HOMO-LUMO gaps were obtained. Microwave rotational spectrum simulations for the slightly asymmetric top ion were carried out for gas phase temperatures 2.73 K and 10 K. These spectra may serve as starting point for laboratory microwave measurements and as screening guide in radio astronomical searches. In addition it was found that the static Jahn-Teller effect in C70+ is the consequence of the mixing of the two highest ground state occupied orbitals, thus it is a pseudo Jahn-Teller effect.

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L. Nemes
Fri, 5 May 23
35/67

Comments: 15 pages, 8 figures, to be published in Monthly Notices of the Royal Astronomical Society, Oxford, UK

Is the Universe anisotropic right now? Comparing the real Universe with the Kasner's space-time [CL]

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http://arxiv.org/abs/2305.02726


We investigate possible astronomical manifestations of space-time anisotropy. The homogeneous vacuum Kasner solution was chosen as a reference anisotropic cosmological model because there are no effects caused by inhomogeneity in this simple model with a constant degree of anisotropy. This anisotropy cannot become weak. The study of its geodesic structure made it possible to clarify the properties of this space-time. It showed that the degree of manifestation of anisotropy varies significantly depending on the travel time of the light from the observed object. For nearby objects, for which it does not exceed half the age of the universe, the manifestations of anisotropy are very small. Distant objects show more pronounced manifestations, for example, in the distribution of objects over the sky and over photometric distances. These effects for each of the individual objects decrease with time, but in general, the manifestations of anisotropy in the Kasner space-time remain constant due to the fact that new sources emerging from beyond the cosmological horizon.We analyse observable signatures of the Kasner-type anisotropy and compare it to observations. These effects were not found in astronomical observations, including the study of the CMB. We can assume that the Universe has always been isotropic or almost isotropic since the recombination era. This does not exclude the possibility of its significant anisotropy at the moment of the Big Bang followed by rapid isotropization during the inflationary epoch.

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S. Parnovsky
Fri, 5 May 23
36/67

Comments: 18 pages, 2 figures

Comparison of Burst Properties between FRB 20190520B and FRB 20121102A [HEAP]

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http://arxiv.org/abs/2305.02595


A comparative analysis of the individual bursts between FRB 20190520B and FRB 20121102A is presented by compiling a sample of bursts in multiple wavelengths. It is found that the peak frequency ($\nu_p$) distribution of the bursts of FRB 20190520B illustrates four discrete peaks in $\sim1-6$ GHz and their spectral width distribution can be fitted with a log-normal function peaking at 0.35 GHz. The discrete $\nu_p$ distribution and the narrow-banded spectral feature are analogous to FRB 20121102A. The burst duration of FRB 20190520B in the rest frame averages 10.72 ms, longer than that of FRB 20121102A by a factor 3. The specific energy ($E_{\rm \mu_{\rm c}}$) at 1.25 GHz of FRB 20190520B observed with the FAST telescope narrowly ranges in $[0.4, 1]\times 10^{38}$ erg, different from the bimodal $E_{\rm \mu_{\rm c}}$ distribution of FRB 20121102A. Assuming a Gaussian spectral profile of the bursts, our Monte Carlo simulation analysis suggests that a power-law (PL) or a cutoff power-law (CPL) energy function can comparably reproduce the $E_{\rm \mu_{\rm c}}$ distribution of FRB 20190520B. The derived energy function index of the PL model is $4.46\pm 0.17$, much steeper than that of FRB 20121102A ($1.82^{+0.10}_{-0.30}$). For the CPL model, we obtain an index of $0.47$ and a cutoff energy of $7.4\times 10^{37}$ erg. Regarding the predicted $\nu_p$ distribution in 1-2 GHz, the CPL model is more preferred than the PL model. These results indicate that FRB 20190520B and FRB 20121102A shares similar spectral properties, but their energy functions are intrinsically different.

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F. Lyu and E. Liang
Fri, 5 May 23
37/67

Comments: 2023,MNRAS in press, 12 pages, 7 figures

Carbon Stars as Standard Candles: An Empirical Test for the Reddening, Metallicity, and Age Sensitivity of the J-region Asymptotic Giant Branch (JAGB) Method [GA]

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http://arxiv.org/abs/2305.02453


The J-region Asymptotic Giant Branch (JAGB) method is a standard candle based on the intrinsic luminosities of carbon stars in the near infrared. For the first time, we directly constrain the impact of metallicity, age, and reddening on the JAGB method. We assess how the mode, skew, and scatter of the JAGB star luminosity function change throughout diverse stellar environments in M31’s NE disk from 13<d<18 kpc using data from the Panchromatic Hubble Andromeda Treasury (PHAT). As expected, the mode is found to be fainter in higher-reddening regions. To cross-check this result, we also measure a fiducial J-band ground-based JAGB distance using data from the UKIRT/WFCam in M31’s outermost disk (18<d<40 kpc) where internal reddening is minimal. We find that this J-band distance modulus agrees well with the F110W distance moduli measured in the lowest reddening regions of the PHAT data, demonstrating the JAGB method is most accurate if measured in the low-reddening outer disks of galaxies. On the other hand, the mode of the JAGB star luminosity function appears empirically to show no dependence on metallicity and age, disputing theoretical predictions that the average luminosity of metal-rich carbon stars is brighter than for metal-poor carbon stars. In conclusion, the JAGB method proves to be a robust standard candle capable of calibrating the luminosities of type Ia supernovae and therefore providing a high-accuracy, high-precision measurement of the Hubble constant.

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A. Lee
Fri, 5 May 23
38/67

Comments: 15 pages, 9 figures 1 tables, submitted to AAS Journals

A complete catalogue of broad-line AGNs and double-peaked emission lines from MaNGA integral-field spectroscopy of 10K galaxies: stellar population of AGNs, supermassive black holes, and dual AGNs [GA]

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http://arxiv.org/abs/2305.02676


We analyse the integral-field spectroscopy data for the $\approx10,000$ galaxies in final data release of the MaNGA survey. We identify 188 galaxies for which the emission lines cannot be described by single Gaussian components. These galaxies can be classified into (1) 38 galaxies with broad $H\alpha$ and [OIII] $\lambda$5007 lines, (2) 101 galaxies with broad $H\alpha$ lines but no broad [OIII] $\lambda$5007 lines, and (3) 49 galaxies with double-peaked narrow emission lines. Most of the broad line galaxies are classified as Active Galactic Nuclei (AGN) from their line ratios. The catalogue helps us further understand the AGN-galaxy coevolution through the stellar population of broad-line region host galaxies and the relation between broad lines’ properties and the host galaxies’ dynamical properties. The stellar population properties (including mass, age and metallicity) of broad-line host galaxies suggest there is no significant difference between narrow-line Seyfert-2 galaxies and Type-1 AGN with broad $H\alpha$ lines. We use the broad-$H\alpha$ line width and luminosity to estimate masses of black hole in these galaxies, and test the $M_{BH}-\sigma_{e}$ relation in Type-1 AGN host galaxies. Furthermore we find three dual AGN candidates supported by radio images from the VLA FIRST survey. This sample may be useful for further studies on AGN activities and feedback processes.

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Y. Fu, M. Cappellari, S. Mao, et. al.
Fri, 5 May 23
39/67

Comments: 20 pages, 17 figures, LaTeX. Submitted to MNRAS

Confining Burst Energy Function and Spectral Fringe Pattern of FRB 20121102A with Multifrequency Observations [HEAP]

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http://arxiv.org/abs/2305.02598


The observed spectral shapes variation and tentative bimodal burst energy distribution (E-distribution) of fast radio burst (FRB) 20121102A with the FAST telescope are great puzzles. Adopting the published multifrequency data observed with the FAST and Arecibo telescopes at $L$ band and the GBT telescope at $C$ band, we investigate these puzzles through Monte Carlo simulations. The intrinsic energy function (E-function) is modeled as $dp/dE\propto E^{-\alpha_{\rm E}}$, and the spectral profile is described as a Gaussian function. A fringe pattern of its spectral peak frequency ($\nu_{\rm p}$) in 0.5-8 GHz is inferred from the $\nu_{\rm p}$ distribution of the GBT sample. We estimate the likelihood of $\alpha_{\rm E}$ and the standard deviation of the spectral profile ($\sigma_{\rm s}$) by utilizing the Kolmogorov–Smirnov (K-S) test probability for the observed and simulated specific E-distributions. Our simulations yields $\alpha_{\rm E}=1.82^{+0.10}{-0.30}$ and $\sigma{\rm s}=0.18^{+0.28}{-0.06}$ ($3\sigma$ confidence level) with the FAST sample. These results suggest that a single power-law function is adequate to model the E-function of FRB 20121102A. The variations of its observed spectral indices and E-distributions with telescopes in different frequency ranges are due to both physical and observational reasons, i.e. narrow spectral width for a single burst and discrete $\nu{p}$ fringe pattern in a broad frequency range among bursts, and the selection effects of the telescope bandpass and sensitivity. The putative $\nu_{p}$ fringe pattern cannot be explained with the current radiation physics models of FRBs. Some caveats of possible artificial effects that may introduce such a feature are discussed.

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F. Lyu, J. Cheng, E. Liang, et. al.
Fri, 5 May 23
40/67

Comments: Published in ApJ,13 pages, 5 figures

The Long and the Short of It: The Benefits and Leverage of Ultraviolet-Radio Galaxy Fitting [GA]

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http://arxiv.org/abs/2305.02443


Traditionally, the far ultraviolet (FUV) to far-infrared (FIR) and radio spectral energy distributions (SEDs) of galaxies have been considered separately despite the common physical process shaping them. In this work, we explore the utility of simultaneously fitting FUV-radio SEDs using an extended version of the ProSpect SED fitting code considering contributions from both free-free and synchrotron emission. We use a small sample of galaxies from the Deep Extragalactic VIsible Legacy Survey (DEVILS) and the Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel (KINGFISH) where high-quality and robust FUV-radio data are available to provide an ideal sample for testing a radio extension of ProSpect. As the parameterisation of the radio extension links the radio continuum to the FIR emission, we explore the benefit of using radio continuum measurements as a constraint on the energy balance between dust attenuation and emission. We find that for situations where MIR-FIR photometry is unavailable, including a 1.4 GHz continuum measurement allows for improved accuracy in recovered star formation rates and dust luminosities of galaxies reducing the median uncertainty by 0.1 and 0.2 dex respectively. We also demonstrate that incorporating 3 and 10 GHz measurements allows for further constraint on the energy balance and therefore the star formation rate and dust luminosity. This demonstrates the advantage of extending FUV-FIR SED fitting techniques to radio frequencies, especially as we move into an era where FIR surveys will remain limited and radio data become abundant (i.e. with the SKA and precursors).

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J. Thorne, A. Robotham, S. Bellstedt, et. al.
Fri, 5 May 23
41/67

Comments: Accepted for publication in MNRAS

JWST NIRSpec spectroscopy of the triply-lensed $z = 10.17$ galaxy MACS0647$-$JD [GA]

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http://arxiv.org/abs/2305.03042


We present JWST/NIRSpec prism spectroscopy of MACS0647-JD, the triply-lensed $z \sim 11$ candidate discovered in HST imaging and spatially resolved by JWST imaging into two components A and B. Spectroscopy of component A yields a spectroscopic redshift $z=10.17$ based on 7 detected emission lines: CIII] $\lambda\lambda$1907,1909, [OII] $\lambda$3727, [NeIII] $\lambda$3869, [NeIII] $\lambda$3968, H$\delta$ $\lambda$4101, H$\gamma$ $\lambda$4340, and [OIII] $\lambda$4363. These are the second-most distant detections of these emission lines to date, in a galaxy observed just 460 million years after the Big Bang. Based on observed and extrapolated line flux ratios we derive a gas-phase metallicity $Z =$ log(O/H) = $7.5 – 8.0$, or $(0.06 – 0.2)$ $Z_\odot$, ionization parameter log($U$) $\sim -1.9\pm0.2$, and an ionizing photon production efficiency ${\rm log}(\xi_{\rm ion})=25.2\pm0.2\,$erg$^{-1}$ Hz. The spectrum has a softened Lyman-$\alpha$ break, evidence for a strong Ly$\alpha$ damping wing, suggesting that MACS0647-JD was unable to ionize its surroundings beyond its immediate vicinity ($R_{\text{HII}} \ll 1$ pMpc). The Ly$\alpha$ damping wing also suppresses the F150W photometry, explaining the slightly overestimated photometric redshift $z = 10.6 \pm 0.3$. MACS0647-JD has a stellar mass log($M/M_\odot$) = $8.1 \pm 0.3$, including $\sim$ 6$\times 10^7 M_\odot$ in component A, most of which formed recently (within $\sim$ 20 Myr) with a star formation rate $2\pm1 M_\odot$ / yr, all within an effective radius $70\pm24\,$pc. The smaller component B ($r \sim 20$) pc is likely older ($\sim$100 Myr) with more dust ($A_V \sim 0.1$ mag), as found previously. Spectroscopy of a fainter companion galaxy C separated by a distance of \about\ 3$\,$kpc reveals a Lyman break consistent with $z = 10.17$. MACS0647-JD is likely the most distant galaxy merger known.

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T. Hsiao, A. Abdurro’uf, D. Coe, et. al.
Fri, 5 May 23
42/67

Comments: 21 pages, 6 figures, submitted to ApJ

Cosmological phase transitions: from perturbative particle physics to gravitational waves [CL]

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http://arxiv.org/abs/2305.02357


Gravitational waves (GWs) were recently detected for the first time. This revolutionary discovery opens a new way of learning about particle physics through GWs from first-order phase transitions (FOPTs) in the early Universe. FOPTs could occur when new fundamental symmetries are spontaneously broken down to the Standard Model and are a vital ingredient in solutions of the matter anti-matter asymmetry problem. The path from a particle physics model to GWs, however, contains many specialized parts and so here we provide a timely review of all the required steps, including: (i) building a finite-temperature effective potential in a particle physics model and checking for FOPTs; (ii) computing transition rates; (iii) analyzing the dynamics of bubbles of true vacuum expanding in a thermal plasma; (iv) characterizing a transition using thermal parameters; and, finally, (v) making predictions for GW spectra using the latest simulations and theoretical results and considering the detectability of predicted spectra at future GW detectors. For each step we emphasize the subtleties, advantages and drawbacks of different methods, discuss open questions and review the state-of-art approaches available in the literature. This provides everything a particle physicist needs to begin exploring GW phenomenology.

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P. Athron, C. Balázs, A. Fowlie, et. al.
Fri, 5 May 23
43/67

Comments: 155 pages, 20 figures, review submitted to Progress in Particle and Nuclear Physics

Synchrotron intensity plots from a relativistic stratified jet [HEAP]

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http://arxiv.org/abs/2305.02929


We examine the effect of a jet transversal structure from magnetohydrodynamic semi-analytical modelling on the total intensity profiles of relativistic jets from active galactic nuclei. In order to determine the conditions for forming double- and triple-peaked transverse intensity profiles, we calculate the radiative transfer for synchrotron emission with self-absorption from the jets described by the models with a constant angular velocity and with a total electric current closed inside a jet. We show that double-peaked profiles appear either in the models with high maximal Lorentz factors or in optically thick conditions. We show that triple-peaked profiles in radio galaxies constrain the fraction of the emitting particles in a jet. We introduce the possible conditions for triple-peaked profiles under the assumptions that nonthermal electrons are preferably located at the jet edges or are distributed according to Ohmic heating.

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V. Frolova, E. Nokhrina and I. Pashchenko
Fri, 5 May 23
44/67

Comments: 22 pages, 11 figures, accepted by MNRAS

Evidence for Large Scale, Rapid Gas Inflows in z~2 Star Forming Disks [GA]

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http://arxiv.org/abs/2305.02959


We report high quality H${\alpha}$/CO, imaging spectroscopy of nine massive, disk galaxies on the star forming, Main Sequence (henceforth ‘SFGs’), near the peak of cosmic galaxy evolution (z~1.1-2.5), taken with the ESO-VLT, IRAM-NOEMA and ALMA. We fit the major axis position-velocity cuts with beam-convolved, forward models with a bulge, a turbulent rotating disk, and a dark matter (DM) halo. We include priors for stellar and molecular gas masses, optical light effective radii and inclinations, and DM masses from our previous rotation curve analyses of these galaxies. We then subtract the inferred 2D model-galaxy velocity and velocity dispersion maps from those of the observed galaxies. We investigate whether the residual velocity and velocity dispersion maps show indications for radial flows. We also carry out kinemetry, a model-independent tool for detecting radial flows. We find that all nine galaxies exhibit significant non-tangential flows. In six SFG, the inflow velocities ($v_r$~30-90 km s$^{-1}$, 10-30% of the rotational component) are along the minor axis of these galaxies. In two cases the inflow appears to be off the minor axis. The magnitudes of the radial motions are in broad agreement with the expectations from analytic models of gravitationally unstable, gas rich disks. Gravitational torques due to clump and bar formation, or spiral arms, drive gas rapidly inward and result in the formation of central disks and large bulges. If this interpretation is correct, our observations imply that gas is transported into the central regions on ~10 dynamical time scales.

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R. Genzel, J. Jolly, D. Liu, et. al.
Fri, 5 May 23
45/67

Comments: 31 pages, 25 figures. Submitted to The Astrophysical Journal

Non-detection of Helium in the Hot Jupiter WASP-48b [EPA]

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http://arxiv.org/abs/2305.02465


Hot Jupiters orbiting extremely close to their host star may experience atmospheric escape due to the large amounts of high-energy radiation they receive. Understanding the conditions under which this occurs is critical, as atmospheric escape is believed to be a driving factor in sculpting planetary populations. In recent years, the near-infrared 10833 \r{A} helium feature has been found to be a promising spectral signature of atmospheric escape. We use transmission spectroscopy to search for excess helium absorption in the extended atmosphere of WASP-48b, a hot Jupiter orbiting a slightly evolved, rapidly-rotating F star. The data were collected using the Habitable Zone Planet Finder spectrograph on the Hobby-Eberly Telescope. Observations were taken over the course of seven nights, from which we obtain three transits. No detectable helium absorption is seen, as absorption depth is measured to $-0.0025\pm0.0021$, or $1.2 \sigma$ from a null detection. This non-detection follows our current understanding of decreasing stellar activity (and thus high-energy radiation) with age. We use a 1D isothermal Parker wind model to compare with our observations and find our non-detection can best be explained with a low planetary mass-loss rate and high thermosphere temperature. We explore our results within the context of the full sample of helium detections and non-detections to date. Surprisingly, comparing helium absorption with the stellar activity index $\rm log\;R’_{HK}$ reveals a large spread in the correlation between these two factors, suggesting that there are additional parameters influencing the helium absorption strength.

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K. Bennett, S. Redfield, A. Oklopčić, et. al.
Fri, 5 May 23
46/67

Comments: 19 pages, 8 figures, 5 tables. Accepted for publication in AJ

The angular power spectrum of gravitational-wave transient sources as a probe of the large-scale structure [CEA]

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http://arxiv.org/abs/2305.02652


We present a new, simulation-based inference method to compute the angular power spectrum of the distribution of foreground gravitational-wave transient events. As a first application of this method, we use the binary black hole mergers observed during the LIGO, Virgo, and KAGRA third observation run to test the spatial distribution of these sources. We find no evidence for anisotropy in their angular distribution. We discuss further applications of this method to investigate other gravitational-wave source populations and their correlations to the cosmological large-scale structure.

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Y. Zheng, N. Kouvatsos, J. Golomb, et. al.
Fri, 5 May 23
47/67

Comments: 6 pages, 5 figures

The FLUKA cross sections for cosmic-ray leptons and uncertainties on current positron predictions [HEAP]

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http://arxiv.org/abs/2305.02958


Cosmic-ray (CR) antiparticles have the potential to reveal signatures of unexpected astrophysical processes and even new physics beyond the Standard Model. Recent CR detectors have provided accurate measurements of the positron flux, revealing the so-called positron excess at high energies. However, the uncertainties related to the modelling of the local positron flux are still very high, significantly affecting our models of positron emission from pulsars and current dark matter searches.
In this work, we report a new set of cross sections for positron and electron production derived from the {\tt FLUKA} code. We compare them with the most extended cross-section data-sets and show the impact of neglecting the positron production from heavy CRs. Then, we review the most significant sources of uncertainties in our current estimations of the secondary positron flux at Earth and examine for the first time the impact of considering the spiral arm structure of the Galaxy in these estimations. Finally, we provide state-of-the-art predictions of the local positron flux and discuss the limitations of our dark matter searches with positrons and difficulties to determine the contribution from pulsars to the positron flux at low energies.

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P. Luque, M. Mazziotta and F. Loparco
Fri, 5 May 23
48/67

Comments: 30 pages, 15 figures and no tables

Dissipative Emergence of Inflation from Quasi-Cyclic Universe [CL]

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http://arxiv.org/abs/2305.02367


Inflationary models, especially those with plateau-type potentials, are consistent with the cosmological data, but inflation itself does not resolve the initial singularity. This singularity is resolved, for example, by the idea of the quantum creation of the Universe from nothing such as the tunneling and no-boundary proposals. The simplest one predicts a closed Universe. Motivated by these facts, we investigate the classical dynamics of a closed Universe with a plateau-type potential. Depending on the initial inflaton field value, the Universe can undergo a variety of events: an immediate Big Crunch, a bounce or cyclic phase, and inflation. Although the non-inflationary solutions may appear irrelevant to our Universe, they can be turned into a single or multiple bounces followed by inflation, taking into account the interactions necessary for the reheating of the Universe after inflation. Thus, the dissipative mechanism in our setup explains both the graceful entry to and exit from inflation and gives us an indirect observational handle on the Universe just after creation. We also comment on the implications of these solutions on the probabilistic interpretations of the wave function of the Universe.

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H. Matsui, A. Papageorgiou, F. Takahashi, et. al.
Fri, 5 May 23
49/67

Comments: 53 pages, 11 figures

Time variability of ultra-fast BAL outflows using SALT: C IV equivalent width analysis [GA]

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http://arxiv.org/abs/2305.02352


We study the time variability (over $\le$7.3 yrs) of ultra-fast outflows (UFOs) detected in a sample of 64 C IV broad absorption line (BAL) quasars (with 80 distinct BAL components) monitored using the Southern African Large Telescope. By comparing the properties of the quasar in our sample with those of a control sample of non-BAL quasars we show that the distributions of black hole mass are different and the bolometric luminosities and optical photometric variations of UFO BAL quasars are slightly smaller compared to that of non-BAL quasars. The detection fraction of C IV equivalent width (W) variability ($\sim$95%), the fractional variability amplitude ($\frac{\Delta W}{W}$) and the fraction of highly variable" BAL (i.e., |$\frac{\Delta W}{W}$| $&gt;$0.67) components ($\sim$ 33%) are higher in our sample compared to the general BAL population. The scatter in $\frac{\Delta W}{W}$ and the fraction ofhighly variable” BALs increase with the time-scale probed. The $\frac{\Delta W}{W}$ distribution is asymmetric at large time scales. We attribute this to the BAL strengthening time scales being shorter than the weakening time scales. The BAL variability amplitude correlates strongly with the BAL properties compared to the quasar properties. BALs with low W, high-velocity, shallow profiles, and low-velocity width tend to show more variability. When multiple BAL components are present a correlated variability is seen between low- and high-velocity components with the latter showing larger amplitude variations. We find an anti-correlation between the fractional variations in the continuum flux and W. While this suggests photoionization-induced variability, the scatter in continuum flux is much smaller than that of W.

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P. Aromal, R. Srianand and P. Petitjean
Fri, 5 May 23
50/67

Comments: 22 pages, accepted for publication in MNRAS

On the problems of detecting Fast Radio Bursts with the LPA LPI [HEAP]

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http://arxiv.org/abs/2305.02778


The paper presents the verification of previously published fast radio bursts (FRB) from the work of V.A. Fedorova and A.E. Rodin, detected in the monitoring data of the Large Phased Array (LPA) radio telescope using a search algorithm based on the convolution of data with a scattered pulse pattern. The same 6-channel data (channel width 415 kHz) were used for verification, in which FRBs were detected with dispersion measures of 247, 570 and 1767 pc/cm3. Additional verification of the published FRB was also carried out in 32-channel data (channel width 78 kHz). We have not been able to confirm any published FRB on the signal-to-noise ratios stated in the original paper. The main errors are caused by incorrect identification of the baseline and incorrect estimation of the standard deviations of noise.

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E. Brylyakova and S. Tyul’bashev
Fri, 5 May 23
51/67

Comments: published in Astronomy Reports, translated by Yandex translator with correction of scientific lexis, 7 pages, 3 figures, 1 table

Witnessing the intracluster medium assembly at the cosmic noon in JKCS041 [CEA]

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http://arxiv.org/abs/2305.02353


In this work we study the intracluster medium of a galaxy cluster at the cosmic noon: JKCS041 at z=1.803. A 28h long Sunyaev-Zel’dovich (SZ) observation using MUSTANG-2 allows us to detect JKCS041, even if intrinsically extremely faint compared to other SZ-detected clusters. We found that the SZ peak is offset from the X-ray center by about 220 kpc in the direction of the brightest cluster galaxy, which we interpret as due to the cluster being observed just after first passage of a major merger. JKCS041 has a low central pressure and a low Compton Y compared to local clusters selected by their intracluster medium (ICM), likely because the cluster is still in the process of assembly but also in part because of a hard-to-quantify bias in current local ICM-selected samples. JKCS041 has a 0.5 dex fainter Y signal than another less massive z~1.8 cluster, exemplifying how much different weak-lensing mass and SZ mass can be at high redshift. The observations we present provide us with the measurement of the most distant resolved pressure profile of a galaxy cluster. Comparison with a library of plausibly descendants shows that JKCS041 pressure profile will likely increase by about 0.7 dex in the next 10 Gyr at all radii.

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S. Andreon, C. Romero, H. Aussel, et. al.
Fri, 5 May 23
52/67

Comments: MNRAS, in press

The Andromeda Galaxy's Last Major Merger: Constraints from the survey of Planetary Nebulae [GA]

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http://arxiv.org/abs/2305.02761


The Andromeda galaxy (M 31) has experienced a tumultuous merger history as evidenced by the many substructures present in its inner halo. We use planetary nebulae (PNe) as chemodynamic tracers to shed light on the recent merger history of M 31. We identify the older dynamically hotter thicker disc in M 31 and a distinct younger dynamically colder thin disc. The two discs are also chemically distinct with the PN chemodynamics implying their formation in a `wet’ major merger (mass ratio ~1:5) ~2.5-4.5 Gyr ago. From comparison of PN line-of-sight velocities in the inner halo substructures with predictions of a major-merger model in M 31, we find that the same merger event that formed the M 31 thick and thin disc is also responsible for forming these substructures. We thereby obtain constraints on the recent formation history of M 31 and the properties of its cannibalized satellite.

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S. Bhattacharya, M. Arnaboldi, O. Gerhard, et. al.
Fri, 5 May 23
53/67

Comments: 5 pages, 1 figure, Proceedings of the IAUS 377: Early Disk-Galaxy Formation from JWST to the Milky Way. Kuala-Lumpur, February 6-10, 2023

No Evidence for Additional Planets at GJ 3470 from TESS and Archival Radial Velocities [EPA]

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http://arxiv.org/abs/2305.02551


The nearby M2 dwarf GJ 3470 has been the target of considerable interest after the discovery of a transiting short-period Neptune-sized planet. Recently, claims regarding the existence of additional transiting planets has gotten some attention, suggesting both the presence of a gas giant in the habitable zone, and that the system hosts a remarkable co-orbital gas giant configuration. We show that the existence of these three additional planets are readily amenable to testing with available data from both ground-based radial velocity data and space-based TESS photometry. A periodogram search of the available radial velocities show no compelling signals at the claimed periods, and the TESS photometry effectively rules out these planets assuming a transiting configuration. While it is doubtlessly possible that additional planets orbit GJ 3470, there is no evidence to date for their existence, and the available data conclusively rule out any planets similar to those considered in this text.

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T. Tarrants and A. Li
Fri, 5 May 23
54/67

Comments: N/A

Tracing Pop III supernovae with extreme energies through the Sculptor dwarf spheroidal galaxy [GA]

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http://arxiv.org/abs/2305.02829


The Sculptor dwarf spheroidal galaxy is old and metal-poor, making it ideal to study the earliest chemical enrichment in the Local Group. We followed up the most metal-poor star known in this (or any external) galaxy, AS0039, with high-resolution ESO VLT/UVES spectra. Our new analysis confirmed its low metallicity, [Fe/H]=-3.90, and that it is extremely C-poor, with A(C)=+3.60, which corresponds to [C/Fe]=-0.33 (accounting for internal mixing). This adds to the evidence of Sculptor being intrinsically C-poor at low [Fe/H]. However, here we also report a new discovery of a carbon-enhanced metal-poor star in Sculptor, DR20080, with no enhancement of Ba (CEMP-no), indicative of enrichment by zero-metallicity low-energy supernovae. This is the first evidence of a dual population of CEMP-no and C-normal stars in Sculptor at $\rm[Fe/H]\leq{-3}$. The fraction of CEMP-no stars is still low, $9^{+11}{-8}\%$ at $\rm -4\leq[Fe/H]\leq-3$, compared to the significantly higher fraction in the Milky Way halo, $\approx40\%$. In addition, we re-derive chemical abundances of light, $\alpha$-, iron peak, and neutron-capture elements in all Sculptor stars at $\rm [Fe/H]\leq-2.8$, with available high-resolution spectra. Our results show that at these low [Fe/H], Sculptor is deficient in light elements (e.g. C, Na, Al, Mg) relative to both the Milky Way halo, and ultra-faint dwarf galaxies, pointing towards significant contribution of high-energy supernovae. Furthermore, the abundance pattern of the star AS0039 is best fitted with a zero-metallicity hypernova progenitor, with a mass of $M=20$M$\odot$. Our results in Sculptor, at $\rm[Fe/H]\leq-3$, therefore suggest significant enrichment by both very low-energy supernovae and hypernovae, solidifying this galaxy as one of the benchmarks for understanding the energy distribution of the first supernova in the Universe.

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&. Skúladóttir, I. Vanni, S. Salvadori, et. al.
Fri, 5 May 23
55/67

Comments: Accepted in A&A

Are all metal-poor stars of second-generation? [GA]

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http://arxiv.org/abs/2305.02358


Hydrodynamical cosmological simulations predict that the metal-free Population III (Pop III) stars were likely very massive and, therefore, short-lived. However, they left their chemical imprint on their descendants, which can also have masses $ < 0.8 \mathrm {M_{\odot}}$ and still be alive today. The Milky Way stellar halo is one of the oldest and most metal-poor component of the Local Group and a peculiar class of stars, the so-called Carbon-Enhanced Metal-Poor (CEMP-no) stars, seem to be directly related to Pop III stars. We aim at revealing if all metal-poor halo stars are true second-generation stars or if they have also been enriched by the subsequent generations of normal (Pop II) stars. For this purpose, we compare the measured carbon and iron abundances of the metal-poor halo stars with the ones predicted by our simple parametric model, varying the pollution level from Pop III and normal stars. We find that only the most C-enhanced and Fe-poor stars enclose in their photospheres the pure imprint of Pop III stars, while, as the [C/Fe] decreases, the probability of being also polluted by normal Pop II stars increases.

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I. Vanni, S. Salvadori and &. Skúladóttir
Fri, 5 May 23
56/67

Comments: 7 pages, 2 figures, accepted for publication in MemSAIt

Carbon dredge-up required to explain the Gaia white dwarf colour-magnitude bifurcation [SSA]

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http://arxiv.org/abs/2305.02827


The Gaia colour-magnitude diagram reveals a striking separation between hydrogen-atmosphere white dwarfs and their helium-atmosphere counterparts throughout a significant portion of the white dwarf cooling track. However, pure-helium atmospheres have Gaia magnitudes that are too close to the pure-hydrogen case to explain this bifurcation. To reproduce the observed split in the cooling sequence, it has been shown that trace amounts of hydrogen and/or metals must be present in the helium-dominated atmospheres of hydrogen-deficient white dwarfs. Yet, a complete explanation of the Gaia bifurcation that takes into account known constraints on the spectral evolution of white dwarfs has thus far not been proposed. In this work, we attempt to provide such a holistic explanation by performing population synthesis simulations coupled with state-of-the-art model atmospheres and evolutionary calculations that account for element transport in the envelopes of white dwarfs. By relying on empirically grounded assumptions, these simulations successfully reproduce the bifurcation. We show that the convective dredge-up of optically invisible traces of carbon from the deep interior is crucial to account for the observations. Neither the convective dilution/mixing of residual hydrogen nor the accretion of hydrogen or metals can be the dominant drivers of the bifurcation. Finally, we emphasize the importance of improving the equation of state of partially ionized carbon in warm dense helium, a key input for our predictions of the amount of dredged-up carbon.

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S. Blouin, A. Bédard and P. Tremblay
Fri, 5 May 23
57/67

Comments: Under review at MNRAS, submitted on 2023-03-15

Seen and unseen: bursty star formation and its implications for observations of high-redshift galaxies with JWST [GA]

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http://arxiv.org/abs/2305.02713


Both observations and simulations have shown strong evidence for highly time-variable star formation in low-mass and/or high-redshift galaxies, which has important observational implications because high-redshift galaxy samples are rest-UV selected and therefore particularly sensitive to the recent star formation. Using a suite of cosmological “zoom-in” simulations at $z>5$ from the Feedback in Realistic Environments (FIRE) project, we examine the implications of bursty star formation histories for observations of high-redshift galaxies with JWST. We characterize how the galaxy observability depends on the star formation history. We also investigate selection effects due to bursty star formation on the physical properties measured, such as the gas fraction, specific star formation rate, and metallicity. We find the observability to be highly time-dependent for galaxies near the survey’s limiting flux due to the SFR variability: as the star formation rate fluctuates, the same galaxy oscillates in and out of the observable sample. The observable fraction $f_\mathrm{obs} \sim 50\%$ at $M_{*} \sim 10^{8.5}$ to $10^{9}\,M_{\odot}$ for a JWST/NIRCam survey reaching a limiting magnitude of $m^\mathrm{lim}_\mathrm{AB} \approx 29$$-$30, representative of surveys such as JADES-Medium and CEERS. JWST-detectable galaxies near the survey limit tend to have properties characteristic of galaxies in the bursty phase: they show 10$-$30% higher cold, dense gas fractions and 80$-$100% higher specific star formation rates at a given stellar mass than galaxies below the rest-UV detection threshold. Our study represents a first step in quantifying selection effects and associated biases due to bursty star formation in studying high-redshift galaxy properties.

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G. Sun, C. Faucher-Giguère, C. Hayward, et. al.
Fri, 5 May 23
58/67

Comments: 7 pages, 4 figures, submitted to MNRAS; comments welcome

Disk-corona modeling for spectral index and luminosity correlation of tidal disruption events [HEAP]

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http://arxiv.org/abs/2305.02639


We present a relativistic disk-corona model for a steady state advective accretion disk to explain the UV to X-ray spectral index $\alpha_{\text{OX}}$ evolution of \textbf{four} tidal disruption event (TDE) sources XMMSL2J1446, XMMSL1J1404, XMMSL1J0740, \textbf{and AT2018fyk}. The viscous stress in our model depends on gas ($P_g$) and total ($P_t$) pressures as $\tau_{r\phi} \propto P_g^{\mu} P_t^{1-\mu}$, where $\mu$ is a constant. We compare various steady and time-dependent sub-Eddington TDE accretion models along with our disk-corona model to the observed $\alpha_{\text{OX}}$ of TDE sources and find that the disk-corona model agrees with the observations better than the other models. We find that $\mu$ is much smaller than unity for TDE sources XMMSL2J1446, XMMSL1J1404, and XMMSL1J0740. We also compare the relativistic model with a non-relativistic disk-corona model. The relativistic accretion dynamics reduce the spectral index relative to the non-relativistic accretion by increasing the energy transport to the corona. We estimate the mass accretion rate for all the sources and find that the observed luminosity follows a nearly linear relation with the mass accretion rate. The ratio of X-ray luminosity from the disk to the corona increases with the mass accretion rate. The observed $\alpha_{\text{OX}}$ shows positive and negative correlations with luminosity. The disk-corona model explains the negative correlation seen in the TDE sources XMMSL1J0740, XMMSL2J1446, and XMMSL1J1404. However, TDE AT2018fyk shows a positive correlation at higher luminosity and shows a better fit when a simple spherical adiabatic outflow model is added to the relativistic disk-corona model. Even though the disk luminosity dominates at a higher mass accretion rate, we show that the accretion models without a corona are unable to explain the observations, and the presence of a corona is essential.

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T. Mageshwaran and S. Bhattacharyya
Fri, 5 May 23
59/67

Comments: 23 pages, 18 figures, 4 tables, accepted for publication in Physical Review D