Astrophysics of Galaxies

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New submissions for Friday, 21 June 2024 (showing 19 of 19 entries )

[1] arXiv:2406.12957 [pdf, html, other]

Title: The imprint of dark matter on the Galactic acceleration field

Arpit Arora, Robyn E. Sanderson, Sukanya Chakrabarti, Andrew Wetzel, Thomas Donlon II, Danny Horta, Sarah R. Loebman, Lina Necib, Micah Oeur

Comments: 14 pages, 5 figures, and 2 tables. Submitted to APJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Measurements of the accelerations of stars enabled by time-series extreme-precision spectroscopic observations, from pulsar timing, and from eclipsing binary stars in the Solar Neighborhood offer insights into the mass distribution of the Milky Way that do not rely on traditional equilibrium modeling. Given the measured accelerations, we can determine a total mass density, and from this, by accounting for the mass in stars, gas, and dust, we can infer the amount of dark matter. Leveraging the FIRE-2 simulations of Milky Way-mass galaxies, we compare vertical acceleration profiles between cold dark matter (CDM) and self-interacting dark matter (SIDM) with constant cross-section of 1 cm$^2$ g$^{-1}$ across three halos with diverse assembly histories. Notably, significant asymmetries in vertical acceleration profiles near the midplane at fixed radii are observed in both CDM and SIDM, particularly in halos recently affected by mergers with satellites of Sagittarius/SMC-like masses or greater. These asymmetries offer a unique window into exploring the merger history of a galaxy. We show that SIDM halos consistently exhibit higher local stellar and dark matter densities and steeper vertical acceleration gradients, up to 30% steeper near the Solar Neighborhood. SIDM halos also manifest a more oblate halo shape in the Solar Neighborhood. Furthermore, enhanced precision in acceleration measurements and larger datasets promise to provide better constraints on the local dark matter density, complementing our understanding from kinematic analysis of their distribution within galaxies.

[2] arXiv:2406.12960 [pdf, html, other]

Title: Hidden Population III Descendants in Ultra-Faint Dwarf Galaxies

Martina Rossi, Stefania Salvadori, Ása Skúladóttir, Irene Vanni, Ioanna Koutsouridou

Comments: Submitted to ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

The elusive properties of the first (Pop III) stars can be indirectly unveiled by uncovering their true descendants. To this aim, we exploit our data-calibrated model for the best-studied ultra-faint dwarf (UFD) galaxy, Boötes I, which tracks the chemical evolution (from carbon to zinc) of individual stars from their formation to the present day. We explore the chemical imprint of Pop III supernovae (SNe), with different explosion energies and masses, showing that they leave distinct chemical signatures in their descendants. We find that UFDs are strongly affected by SNe-driven feedback resulting in a very low fraction of metals retained by their gravitational potential well (< 2.5 %). Furthermore, the higher the Pop III SN explosion energy, the lower the fraction of metals retained. Thus, the probability to find descendants of energetic Pair Instability SNe is extremely low in these systems. Conversely, UFDs are ideal cosmic laboratories to identify the fingerprints of less massive and energetic Pop III SNe through their [X/Fe] abundance ratios. Digging into the literature data of Boötes I, we uncover three hidden Pop III descendants: one mono-enriched and two multi-enriched. These stars show the chemical signature of Pop III SNe in the mass range $[20-60]\rm M_{\odot}$, spanning a wide range in explosion energies $[0.3-5] 10^{51}$ erg. In conclusion, Pop III descendants are hidden in ancient UFDs but those mono-enriched by a single Pop III SN are extremely rare. Thus, self-consistent models such as the one presented here are required to uncover these precious fossils and probe the properties of the first Pop III supernovae.

[3] arXiv:2406.12969 [pdf, html, other]

Title: Our Halo of Ice and Fire: Strong Kinematic Asymmetries in the Galactic Halo

Jiwon Jesse Han, Charlie Conroy, Dennis Zaritsky, Ana Bonaca, Nelson Caldwell, Vedant Chandra, Yuan-Sen Ting

Comments: submitted to ApJ; comments welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The kinematics of the stellar halo hold important clues to the assembly history and mass distribution of the Galaxy. In this study, we map the kinematics of stars across the Galactic halo with the H3 Survey. We find a complex distribution that breaks both azimuthal symmetry about the $Z$-axis and mirror symmetry about the Galactic plane. This asymmetry manifests as large variations in the radial velocity dispersion $\sigma_r$ from as ``cold'' as 70 $\text{km}\text{ s}^{-1}$ to as ``hot'' as 160 $\text{km}\text{ s}^{-1}$. We use stellar chemistry to distinguish accreted stars from in-situ stars in the halo, and find that the accreted population has higher $\sigma_r$ and radially biased orbits, while the in-situ population has lower $\sigma_r$ and isotropic orbits. As a result, the Galactic halo kinematics are highly heterogeneous and poorly approximated as being spherical or axisymmetric. We measure radial profiles of $\sigma_r$ and the anisotropy parameter $\beta$ over Galactocentric radii $10-80\text{ kpc}$, and find that discrepancies in the literature are due to the nonspherical geometry and heterogeneous nature of the halo. Investigating the effect of strongly asymmetric $\sigma_r$ and $\beta$ on equilibrium models is a path forward to accurately constraining the Galactic gravitational field, including its total mass.

[4] arXiv:2406.12977 [pdf, html, other]

Title: On the evolution of low-mass central galaxies in the vicinity of massive structures

Daniela Palma, Ivan Lacerna, M. Celeste Artale, Antonio D. Montero-Dorta, Andrés N. Ruiz, Sofía A. Cora, Facundo Rodriguez, Diego Pallero, Ana O'Mill, Nelvy Choque-Challapa

Comments: 16 pages, 13 figures, submitted to A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We investigate low-mass central galaxies with Mstar = $10^{9.5}-10^{10}$ Msun/h, located near massive groups and galaxy clusters using the TNG300 and MDPL2-SAG simulations. We set out to study their evolution, aiming to find hints about the large-scale conformity signal they produce. We also use a control sample of low-mass central galaxies located far away from massive structures. For both samples, we find a sub-population of galaxies that were accreted by another halo in the past but are now considered central galaxies; we refer to these objects as former satellites. The fraction of former satellites is higher for quenched central galaxies near massive systems: 45% in TNG300 and 17% in MDPL2-SAG. Our results in TNG300 show that former satellites were typically hosted by massive dark matter halos (M200 $\geq 10^{13}$ Msun/h) at z$\sim$0.3, followed by a drop in halo mass at lower redshifts. In addition, we find a strong drop in the total gas mass at z$\leq$1 for quenched central galaxies near galaxy groups and clusters produced by these former satellites as well. By removing former satellites, the evolution of quenched central galaxies is fairly similar to those of the quenched control galaxies, showing small differences at low-z. For MDPL2-SAG, former satellites were hosted by less massive halos, with a mean halo mass around $10^{11}$ Msun/h, and the evolution remains equal before and after removing former satellites. We also measure the two-halo conformity, i.e., the correlation in the specific SFR between low-mass central galaxies and their neighbors at Mpc scales, and how former satellites contribute to the signal at z=0, 0.3, and 1. The conformity signal decreases from z=0 to z=1 in MDPL2-SAG but it increases in TNG300. However, after removing former satellites in TNG300, the signal is strongly reduced but almost does not change at z$\leq$0.3, and it disappears at z=1 (abridged).

[5] arXiv:2406.13005 [pdf, html, other]

Title: Fast SMBH growth in the SPT2349--56 protocluster at $z=4.3$

Fabio Vito, William N. Brandt, Andrea Comastri, Roberto Gilli, Rob J. Ivison, Giorgio Lanzuisi, Bret D. Lehmer, Ivan E. Lopez, Paolo Tozzi, Cristian Vignali

Comments: Submitted to A&A, referee comments included

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Protoclusters at $z>2$ are gas-rich regions characterized by high star-formation activity. The same physical properties that enhance star formation in protoclusters are also thought to boost the growth of SMBHs. We aim to test this scenario by probing the AGN content of SPT2349-56, a massive, gas-rich, and highly star-forming protocluster core at $z=4.3$ discovered as an overdensity of DSFGs, via Chandra (200 ks) observations, and comparing the results with the field environment. We detected two protocluster members, corresponding to an AGN fraction among DSFGs of $\approx10\%$. This value is consistent with other protoclusters at $z=2-4$, but higher than the AGN incidence among DSFGs in the field environment. Both AGN are heavily obscured sources and hosted in star-forming galaxies with $\approx3\times10^{10}\,\mathrm{M_\odot}$ stellar masses. We estimate that the ISM in the host galaxies can contribute significantly to the nuclear obscuration. One of the two AGN is highly luminous ($L_X=2\times10^{45}\,\mathrm{erg\,s^{-1}}$) and Compton-thick ($N_H=2\times10^{24}\,\mathrm{cm^{-2}}$), and likely powered by a $M_{BH}>6\times10^8\,\mathrm{M_\odot}$ SMBH. Its high accretion rate suggests that it is in the phase of efficient growth required to explain the presence of extremely massive SMBHs in the centers of local galaxy clusters. Considering SPT2349-56 and DRC, a similar protocuster at $z=4$, we find that gas-rich protocluster cores at $z\approx4$ enhance the triggering of luminous (log$\frac{L_X}{\mathrm{erg\,s^{-1}}}=45-46$) AGN by 3-5 orders of magnitude with respect to the field environment. Our results indicate that gas-rich protoclusters at high redshift boost the growth of SMBHs, which will likely impact the subsequent evolution of the structures, and thus represent key science targets to obtain a complete understanding of the relation between environment and galaxy evolution.

[6] arXiv:2406.13021 [pdf, html, other]

Title: Forgotten treasures in the HST/FOC UV imaging polarimetric archives of active galactic nuclei. II. Mrk 463E

Thibault Barnouin (1), Frédéric Marin (1), Enrique Lopez-Rodriguez (2) ((1) Observatoire Astronomique de Strasbourg, Université de Strasbourg, France, (2) Kavli Institute for Particle Astrophysics and Cosmolog, Stanford University, USA)

Comments: 9 pages, 7 figures, submitted Astronomy & Astrophysics, comments are welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The Mrk 463 system is known to host two powerful sources separated by about 4 kpc, both identified as active galactic nuclei (AGN). This makes the Mrk 463 system a unique laboratory to study the geometry and dynamics of galaxy merging and its relation to AGN duty cycles. The eastern nuclei, Mrk 463E, is the brightest of the two and thus a prime target for a polarimetric study. It is classified as a Seyfert 2 galaxy, meaning that one could expect large polarization degrees from scattering off electrons and dust in the polar winds. In the continuity of our series of papers, we reduced archived and previously unpublished polarization observations obtained with the Faint Object Camera (FOC) onboard the Hubble Space Telescope (HST), to obtain a high resolution near ultraviolet (near-UV) polarization map of the Mrk 463E nuclei. We coupled this map to near infrared (NIR) and X-ray observations to get a clear picture of the geometric arrangement of matter around the core of Mrk 463E. We found that the nucleus location is further South from the optical peak flux than previously estimated. The strongly polarized conical wind has a half-opening angle of ~15° and display three main periods of mass ejection. Its polarization allowed us to estimate the AGN inclination towards the observer (~55°) Finally, our maps revealed a gas streamer connecting Mrk 463E and Mrk 463W, with a tentative detection of a large kpc-scale ordered magnetic field connecting both galaxies. This unpublished observation turned out to offer more than the original proposal asked for and allowed to derive tight geometric and dynamical constraints for Mrk 463E. High resolution radio maps and IR polarimetry are now necessary to further study the jet and the newly discovered gas streamer.

[7] arXiv:2406.13169 [pdf, html, other]

Title: A surprising excess of radio emission in extremely stable quasars: a unique clue to jet launching?

Wen-Yong Kang, Jun-Xian Wang, Zhen-Yi Cai, Hao-Chen Wang, Wen-Ke Ren, Mai Liao, Feng Yuan, Andrzej Zdziarski, Xinwu Cao

Comments: 11 pages, 16 figures, Accepted by ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

Quasars are generally divided into jetted radio-loud and non-jetted radio-quiet ones, but why only 10% quasars are radio loud has been puzzling for decades. Other than jet-induced-phenomena, black hole mass, or Eddington ratio, prominent difference between jetted and non-jetted quasars has scarcely been detected. Here we show a unique distinction between them and the mystery of jet launching could be disclosed by a prominent excess of radio emission in extremely stable quasars (ESQs, i.e., type 1 quasars with extremely weak variability in UV/optical over 10 years). Specifically, we find that $>$ 25% of the ESQs are detected by the FIRST/VLASS radio survey, while only $\sim$ 6-8% of the control sample, matched in redshift, luminosity, and Eddington ratio, are radio-detected. The excess of radio detection in ESQs has a significance of 4.4 $\sigma$ (99.9995%), and dominantly occurs at intermediate radio loudness with R $\sim$ 10 - 60. The radio detection fraction of ESQs also tends to increase in the ESQ samples selected with more stringent thresholds. Our results are in contrast to the common view that RL quasars are likely more variable in UV/optical due to jet contribution. New clues/challenge posed by our findings highlight the importance of extensive follow-up observations to probe the nature of jets in ESQs, and theoretical studies on the link between jet launching and ESQs. Moreover, our results makes ESQs, an essential population which has never been explored, unique targets in the burgeoning era of time domain astronomy, like their opposite counterparts of quasars exhibiting extreme variability or changing-look features.

[8] arXiv:2406.13254 [pdf, other]

Title: The multi-component fitting to the star formation histories in the TNG simulation

Yang Wang, Chengxing Dong, Hengxin Ruan, Qiufan Lin, Yucheng Zhang, Shupei Chen

Journal-ref: ApJ 968 115 (2024)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The star formation history (SFH) is a key issue in the evolution of galaxies. In this work, we developed a model based on a Gaussian and gamma function mixture to fit SFHs with varying numbers of components. Our primary objective was to use this model to reveal the shape of SFHs and the corresponding physical driving factors. Specifically, we applied this model to fit SFHs from the TNG100-1 simulation. Our study led to the following findings: 1) Our model fits with TNG star formation histories well, especially for high-mass and red galaxies; 2) A clear relationship exists between the number and shape of fitted components and the mass and color of galaxies, with notable differences observed between central/isolated and satellite galaxies. 3) Our model allowed us to extract different episodes of star formation within star formation histories with ease and analyze the duration and timing of each star formation episode. Our findings indicated a strong relationship between the timing of each star formation episode and galaxy mass and color.

[9] arXiv:2406.13346 [pdf, html, other]

Title: Comparing extragalactic megahertz-peaked spectrum and gigahertz-peaked spectrum sources

F.J. Ballieux, J.R. Callingham, H.J.A. Röttgering, M.M. Slob

Comments: Accepted for publication in Astronomy & Astrophysics. 16 pages, 9 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Recent sensitive wide-field radio surveys, such as the LOFAR Two Meter Sky Survey (LoTSS), the LOFAR LBA Sky Survey (LoLSS), and the Very Large Array Sky Survey (VLASS), enable the selection of statistically large samples of peaked-spectrum (PS) sources. PS sources are radio sources that have a peak in their radio continuum spectrum and are observed to be compact. They are often considered to be the precursors to large radio galaxies. We present a sample of 8,032 gigahertz-peaked spectrum (GPS) sources with spectral turnovers near 1400 MHz, and a sample of 506 megahertz-peaked spectrum (MPS) sources with turnovers near 144 MHz. Our GPS sample is over five times larger than any previously known sample of PS sources. These large sample sizes allow us to make a robust comparison between GPS sources and MPS sources, such that we can investigate the differences between these types of sources, and study their lifetimes. The shape of the source counts of both samples match that of the general radio-loud active galactic nuclei (AGN) samples, scaled down by a factor 44 $\pm$ 2 for the MPS sample, and a factor 28 $\pm$ 1 for the GPS sample. Assuming no cosmological evolution, these offsets imply that both MPS and GPS sources have shorter duration than general radio-loud AGN, with MPS sources having an $\approx$1.6 times shorter lifespan than GPS sources. The shorter duration of MPS sources relative to GPS sources can be explained by the transition between GPS and MPS sources coinciding with the jet breakout phase of PS sources, such that GPS sources traverse through the surrounding medium at a lower speed than MPS sources. Such evolution has been observed in simulations of PS source evolution.

[10] arXiv:2406.13496 [pdf, html, other]

Title: Tidal features and disc thicknesses of edge-on galaxies in the SDSS Stripe 82

Maria N. Skryabina, Kyle R. Adams, Aleksandr V. Mosenkov

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We examine deep optical images of edge-on galaxies selected from the Sloan Digital Sky Survey (SDSS) Stripe\,82. The entire sample consists of over 800 genuine edge-on galaxies with spectroscopic redshifts out to $z\sim0.2$. To discern the faintest details around the galaxies, we use three different data sources with a photometric depth of down to 30 mag\,arcsec$^{-2}$ in the $r$ band: SDSS Stripe\,82, Hyper Suprime-Cam Strategic Program, and DESI Legacy Imaging Surveys. Our analysis of the deep images reveals a variety of low surface brightness features. 49 galaxies exhibit prominent tidal structures, including tidal tails, stellar streams, bridges, and diffuse shells. Additionally, 56 galaxies demonstrate peculiar structural features such as lopsided discs, faint warps, and dim polar rings. Overall, we detect low surface brightness structures in 94 galaxies out of 838, accounting for 11\% of the sample. Notably, the fraction of tidal structures is only 5.8\%, which is significantly lower than that obtained in modern cosmological simulations and observations. Previous studies have shown that strongly interacting galaxies have stellar discs about 1.5--2 times thicker than those without apparent interactions. In an analysis where tidal features are carefully masked for precise disc axis ratio measurements, we show that discs of galaxies with tidal features are 1.33 times thicker, on average, than control galaxies that do not have visible tidal features. Furthermore, we find that edge-on galaxies with tidal structures tend to have a higher fraction of oval and boxy discs than galaxies without tidal features.

[11] arXiv:2406.13554 [pdf, html, other]

Title: The emergence of the Star Formation Main Sequence with redshift unfolded by JWST

P. Rinaldi, R. Navarro-Carrera, K. I. Caputi, E. Iani, G. Ostlin, L. Colina, S. Alberts, J. Alvarez-Marquez, M. Annunziatella, L. Boogaard, L. Costantin, J. Hjorth, D. Langeroodi, J. Melinder, T. Moutard, F. Walter

Comments: 15 pages, 4 figures. Submitted to ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We investigate the correlation between stellar mass (M*) and star formation rate (SFR) across the stellar mass range log10(M*/Msun)~6-11. We consider almost 50,000 star-forming galaxies at z~3-7, leveraging data from COSMOS/SMUVS, JADES/GOODS-SOUTH, and MIDIS/XDF. This is the first study spanning such a wide stellar mass range without relying on gravitational lensing effects. We locate our galaxies on the SFR-M* plane to assess how the location of galaxies in the star-formation main sequence (MS) and starburst (SB) region evolves with stellar mass and redshift. We find that the two star-forming modes tend to converge at log10(M*/Msun) < 7, with all galaxies found in the SB mode. By dissecting our galaxy sample in stellar mass and redshift, we show that the emergence of the star-formation MS is stellar-mass dependent: while in galaxies with log10(M*/Msun) > 9 the MS is already well in place at z = 5-7, for galaxies with log10(M*/Msun)~7-8 it only becomes significant at z<4. Overall, our results are in line with previous findings that the SB mode dominates amongst low stellar-mass galaxies. The earlier emergence of the MS for massive galaxies is consistent with galaxy downsizing.

[12] arXiv:2406.13589 [pdf, html, other]

Title: Hydrodynamic simulation of Cygnus OB2: the absence of a cluster wind termination shock

Thibault Vieu, Cormac J. K. Larkin, Lucia Härer, Brian Reville, Andreas A. C. Sander, Varsha Ramachandran

Comments: 15 pages, 12 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

We perform a large-scale hydrodynamic simulation of a massive star cluster whose stellar population mimics that of the Cygnus OB2 association. The main-sequence stars are first simulated during 1.6 Myr, until a quasi-stationary state is reached. At this time the three Wolf-Rayet stars observed in Cygnus OB2 are added to the simulation, which continues to 2 Myr. Using a high-resolution grid in the centre of the domain, we can resolve the most massive stars individually, which allows us to probe the kinetic structures at small (parsec) scales. We find that, although the cluster excavates a spherical "superbubble" cavity, the stellar population is too loosely distributed to blow a large-scale cluster wind termination shock, and that collective effects from wind-wind interactions are much less efficient than usually assumed. This challenges our understanding of the ultra-high energy emission observed from the region.

[13] arXiv:2406.13613 [pdf, html, other]

Title: Einasto gravitational potentials have difficulty to hold spherically symmetric stellar systems with cores

Jorge Sanchez Almeida (1 and 2) ((1) Instituto de Astrofisica de Canarias, Tenerife, Spain, (2) Departamento de Astrofisica, Universidad de La Laguna, Tenerife, Spain)

Comments: RNAAS complementing our previous paper Sanchez Almeida et al. (2023, ApJ, 954, 153; doi: https://doi.org/10.3847/1538-4357/ace534)

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

It was known that an ideal spherically symmetric stellar system with isotropic velocities and an inner core cannot reside in a Navarro, Frenk, and White (NFW) gravitational potential. The incompatibility can be pinned down to the radial gradient of the NFW potential in the very center of the system, which differs from zero. The gradient is identically zero in an Einasto potential, also an alternative representation of the dark matter (DM) halos created by the kind of cold DM (CDM) defining the current cosmological model. Here we show that, despite the inner gradient being zero, stellar cores are also inconsistent with Einasto potentials. This result may have implications to constrain the nature of DM through interpreting the stellar cores often observed in dwarf galaxies.

[14] arXiv:2406.13732 [pdf, html, other]

Title: On the dark matter content of ultra-diffuse galaxies

Andrey Kravtsov

Comments: 9 pages, 6 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

I compare the dark matter content within stellar half-mass radius expected in a $\Lambda$CDM-based galaxy formation model with existing observational estimates for the observed dwarf satellites of the Milky Way and ultra-diffuse galaxies (UDGs). The model reproduces the main properties and scaling relations of dwarf galaxies, in particular their stellar mass-size relation. I show that the model also reproduces the relation between the dark matter mass within the half-mass radius, $M_{\rm dm}(<r_{1/2})$, and stellar mass exhibited by the observed dwarf galaxies. The scatter in the $M_{\rm dm}(<r_{1/2})-M_\star$ relation is driven primarily by the broad range of sizes of galaxies of a given stellar mass. I also show the $M_{\rm dm}(<r_{1/2})$ of UDGs are within the range expected in the model for their stellar mass, but they tend to lie above the median relation due to their large sizes. The upper limits on $M_{\rm dm}(<r_{1/2})$ for the dark matter deficient UDGs are also consistent with the range of dark matter masses expected in the model. The most dark matter-deficient galaxies of a given size correspond to halos with the smallest concentrations and the largest ratios of $M_\star/M_{\rm 200c}$. Conversely, the most dark matter-dominated galaxies are hosted by the highest concentration halos with the smallest $M_\star/M_{\rm 200c}$ ratios. The model indicates that the scatter between $M_{\rm dm}(<r_{1/2})$ and $M_{\rm 200c}$ is large, which renders inference of the virial mass from $M_{\rm dm}(<r_{1/2})$ uncertain and dependent on specific assumptions about the halo mass profile. Results presented in this paper indicate that dark matter-deficient UDGs may represent a tail of the expected dark matter profiles, especially if the effect of feedback on these profiles is taken into account.

[15] arXiv:2406.13745 [pdf, html, other]

Title: Formation of super-thin galaxies in Illustris-TNG

Jianhong Hu, Dandan Xu, Cheng Li

Comments: 16 pages, 15 figures, accepted for publication in Research in Astronomy and Astrophysics

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Superthin galaxies are observed to have stellar disks with extremely small minor-to-major axis ratios. In this work, we investigate the formation of superthin galaxies in the TNG100 simulation. We trace the merger history and investigate the evolution of galaxy properties of a selected sample of superthin galaxies and a control sample of galaxies that share the same joint probability distribution in the stellar-mass and color diagram. Through making comparisons between the two galaxy samples, we find that present-day superthin galaxies had similar morphologies as the control sample counterparts at higher redshifts, but have developed extended flat `superthin' morphologies since $z \sim 1$. During this latter evolution stage, superthin galaxies undergo overwhelmingly higher frequency of prograde mergers (with orbit-spin angle $\theta_{\rm orb} \leqslant 40^\circ$). Accordingly the spins of their dark matter halos have grown significantly and become noticeably higher than that of their normal disk counterparts. This further results in the buildup of their stellar disks at larger distances much beyond the regimes of normal disk galaxies. We also discuss the formation scenario of those superthin galaxies that live in larger dark matter halos as satellite galaxies therein.

[16] arXiv:2406.13801 [pdf, html, other]

Title: A Census of the Deep Radio Sky with the VLA I: 10GHz Survey of the GOODS-N field

Eric F. Jiménez-Andrade, Eric J. Murphy, Emmanuel Momjian, James J. Condon, Ranga-Ram Chary, Russ Taylor, Mark Dickinson

Comments: Accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present the first high-resolution, high-frequency radio continuum survey that fully maps an extragalactic deep field: the 10GHz survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field. This is a Large Program of the Karl G. Jansky Very Large Array that allocated 380 hours of observations using the X-band ($8-12$GHz) receivers, leading to a 10GHz mosaic of the GOODS-field with an average rms noise $\sigma_{\rm n}=671\,\rm nJy\,beam^{-1}$ and angular resolution $\theta_{1/2}=0.22$arcsec across 297$\rm arcmin^2$. To maximize the brightness sensitivity we also produce a low-resolution mosaic with $\theta_{1/2}=1.0$arcsec and $\sigma_{\rm n}=968\,\rm nJy\,beam^{-1}$, from which we derive our master catalog containing 256 radio sources detected with peak signal-to-noise ratio $\geq 5$. Radio source size and flux density estimates from the high-resolution mosaic are provided in the master catalog as well. The total fraction of spurious sources in the catalog is 0.75%. Monte Carlo simulations are performed to derive completeness corrections of the catalog. We find that the 10GHz radio source counts in the GOODS-N field agree, in general, with predictions from numerical simulations/models and expectations from 1.4 and 3GHz radio counts.

[17] arXiv:2406.13924 [pdf, html, other]

Title: Impact of Internal Dust Correction on the Stellar Populations of Galaxies Estimated Using the Full Spectrum Fitting

Joon Hyeop Lee, Hyunjin Jeong, Jiwon Chung, Mina Pak, Sree Oh

Comments: 10 pages, 8 figures, accepted for publication in Journal of the Korean Astronomical Society

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Full spectrum fitting is a powerful tool for estimating the stellar populations of galaxies, but the fitting results are often significantly influenced by internal dust attenuation. For understanding how the choice of the internal dust correction method affects the detailed stellar populations estimated from the full spectrum fitting, we analyze the Sydney-Australian Astronomical Observatory Multi-object Integral field spectrograph (SAMI) galaxy survey data using the Penalized PiXel-Fitting (PPXF) package. Three choices are compared: (Choice-1) using the PPXF reddening option, (Choice-2) using the multiplicative Legendre polynomial, and (Choice-3) using none of them (no dust correction). In any case, the total mean stellar populations show reasonable mass-age and mass-metallicity relations (MTR and MZR), although the correlations appear to be strongest for Choice-1 (MTR) and Choice-2 (MZR). When we compare the age-divided mean stellar populations, the MZR of young (< 10^9.5 yr ~ 3.2 Gyr) stellar components in Choice-2 is consistent with the gas-phase MZR, whereas those in the other two choices hardly are. On the other hand, the MTR of old (>= 10^9.5 yr) stellar components in Choice-1 seems to be more reasonable than that in Choice-2, because the old stellar components in low-mass galaxies tend to be relatively younger than those in massive galaxies. Based on the results, we provide empirical guidelines for choosing the optimal options for dust correction.

[18] arXiv:2406.13926 [pdf, other]

Title: Effects of Radiative Transfer on the Observed Anisotropy in MHD Turbulent Molecular Simulations

D. Hernández-Padilla, A. Esquivel, A. Lazarian, P. F. Velázquez, J. Cho

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We study the anisotropy of centroid and integrated intensity maps with synthetic observations. We perform post-process radiative transfer including the optically thick regime that was not covered in Hernández-Padilla et al. (2020). We consider the emission in various CO molecular lines, that range from optically thin to optically thick ($\mathrm{^{12}CO}$, $\mathrm{^{13}CO}$, $\mathrm{C^{18}O}$, and $\mathrm{C^{17}O}$). The results for the velocity centroids are similar to those in the optically thin case. For instance, the anisotropy observed can be attributed to the Alfvén mode, which dominates over the slow and fast modes when the line of sight is at a high inclination with respect to the mean magnetic field. A few differences arise in the models with higher opacity, where some dependence on the sonic Mach number becomes evident. In contrast to the optically thin case, maps of integrated intensity become more anisotropic in optically thick lines. In this situation the scales probed are restricted, due to absorption, to smaller scales which are known to be more anisotropic. We discuss how the sonic Mach number can affect the latter results, with highly supersonic cases exhibiting a lower degree of anisotropy.

[19] arXiv:2406.14134 [pdf, html, other]

Title: Hypervelocity star observations constrain the Galactic Centre

Sill Verberne, Elena Maria Rossi, Sergey E. Koposov, Tommaso Marchetti, Konrad Kuijken, Zephyr Penoyre, Fraser A. Evans, Dimitris Souropanis, Clár-Bríd Tohill

Comments: 17 pages, 16 figures, submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

Hypervelocity stars (HVSs) are stars which have been ejected from the Galactic Centre (GC) at velocities of up to a few thousand km/s. They are tracers of the Galactic potential and can be used to infer properties of the GC, such as the initial-mass function and assembly history. HVSs are rare, however, with only about a dozen promising candidates discovered so far. In this work we use a novel, highly efficient method to identify new HVS candidates in Gaia. This method uses the nearly radial trajectories of HVSs to infer their distances and velocities based on their position and Gaia proper motion alone. Through comparison of inferred distances with Gaia parallaxes and photometry we identified 600 HVS candidates with G<20 including the previously discovered S5-HVS1, out of which we obtained ground-based follow-up observations for 196 stars. As we found no new HVSs based on their radial velocity, we used detailed HVS ejection simulations to significantly improve previous HVS ejection rate constraints. In particular, the ejection rate of HVSs more massive than 1 M$_\odot$ cannot be higher than $10^{-5}$ yr$^{-1}$ at $2\sigma$ significance. Additionally, we predict that there are 5-45 unbound HVSs in the complete Gaia catalogue ($1\sigma$ interval), most of which will be main-sequence stars of a few M$_\odot$ at heliocentric distances of tens to hundreds of kpc. By comparing our results to literature HVS candidates, we find an indication of either a time-dependent ejection rate of HVSs or a non-GC origin of many previously identified HVS candidates.

Cross submissions for Friday, 21 June 2024 (showing 12 of 12 entries )

[20] arXiv:2406.12917 (cross-list from astro-ph.IM) [pdf, html, other]

Title: The Black Hole Explorer: Motivation and Vision

Michael D. Johnson, Kazunori Akiyama, Rebecca Baturin, Bryan Bilyeu, Lindy Blackburn, Don Boroson, Alejandro Cardenas-Avendano, Andrew Chael, Chi-kwan Chan, Dominic Chang, Peter Cheimets, Cathy Chou, Sheperd S. Doeleman, Joseph Farah, Peter Galison, Ronald Gamble, Charles F. Gammie, Zachary Gelles, Jose L. Gomez, Samuel E. Gralla, Paul Grimes, Leonid I. Gurvits, Shahar Hadar, Kari Haworth, Kazuhiro Hada, Michael H. Hecht, Mareki Honma, Janice Houston, Ben Hudson, Sara Issaoun, He Jia, Svetlana Jorstad, Jens Kauffmann, Yuri Y. Kovalev, Peter Kurczynski, Robert Lafon, Alexandru Lupsasca, Robert Lehmensiek, Chung-Pei Ma, Daniel P. Marrone, Alan P. Marscher, Gary J. Melnick, Ramesh Narayan, Kotaro Niinuma, Scott C. Noble, Eric J. Palmer, Daniel C. M. Palumbo, Lenny Paritsky, Eliad Peretz, Dominic Pesce, Alexander Plavin, Eliot Quataert, Hannah Rana, Angelo Ricarte, Freek Roelofs, Katia Shtyrkova, Laura C. Sinclair, Jeffrey Small, Sridharan Tirupati Kumara, Ranjani Srinivasan, Andrew Strominger, Paul Tiede, Edward Tong, Jade Wang, Jonathan Weintroub, Maciek Wielgus, George Wong, Xinyue Alice Zhang

Comments: Proceedings for SPIE Astronomical Telescopes and Instrumentation

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

We present the Black Hole Explorer (BHEX), a mission that will produce the sharpest images in the history of astronomy by extending submillimeter Very-Long-Baseline Interferometry (VLBI) to space. BHEX will discover and measure the bright and narrow "photon ring" that is predicted to exist in images of black holes, produced from light that has orbited the black hole before escaping. This discovery will expose universal features of a black hole's spacetime that are distinct from the complex astrophysics of the emitting plasma, allowing the first direct measurements of a supermassive black hole's spin. In addition to studying the properties of the nearby supermassive black holes M87* and Sgr A*, BHEX will measure the properties of dozens of additional supermassive black holes, providing crucial insights into the processes that drive their creation and growth. BHEX will also connect these supermassive black holes to their relativistic jets, elucidating the power source for the brightest and most efficient engines in the universe. BHEX will address fundamental open questions in the physics and astrophysics of black holes that cannot be answered without submillimeter space VLBI. The mission is enabled by recent technological breakthroughs, including the development of ultra-high-speed downlink using laser communications, and it leverages billions of dollars of existing ground infrastructure. We present the motivation for BHEX, its science goals and associated requirements, and the pathway to launch within the next decade.

[21] arXiv:2406.12984 (cross-list from astro-ph.SR) [pdf, html, other]

Title: Constraining the Stellar Masses and Origin of the Protostellar VLA 1623 System

Sarah I Sadavoy, Patrick Sheehan, John J. Tobin, Nadia M. Murillo, Richard Teague, Ian Stephens, Thomas Henning, Philip C. Myers, Edwin A. Bergin

Comments: Accepted to A&A; 16 pages, 12 figures

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

We present ALMA Band 7 molecular line observations of the protostars within the VLA 1623 system. We map C$^{17}$O (3 - 2) in the circumbinary disk around VLA 1623A and the outflow cavity walls of the collimated outflow. We further detect red-shifted and blue-shifted velocity gradients in the circumstellar disks around VLA 1623B and VLA 1623W that are consistent with Keplerian rotation. We use the radiative transfer modeling code, pdspy, and simple flared disk models to measure stellar masses of $0.27 \pm 0.03$ M$_\odot$, $1.9^{+0.3}_{-0.2}$ M$_\odot$, and $0.64 \pm 0.06$ M$_\odot$ for the VLA 1623A binary, VLA 1623B, and VLA 1623W, respectively. These results represent the strongest constraints on stellar mass for both VLA 1623B and VLA 1623W, and the first measurement of mass for all stellar components using the same tracer and methodology. We use these masses to discuss the relationship between the young stellar objects (YSOs) in the VLA 1623 system. We find that VLA 1623W is unlikely to be an ejected YSO, as has been previously proposed. While we cannot rule out that VLA 1623W is a unrelated YSO, we propose that it is a true companion star to the VLA 1623A/B system and that the these stars formed in situ through turbulent fragmentation and have had only some dynamical interactions since their inception.

[22] arXiv:2406.13079 (cross-list from astro-ph.CO) [pdf, html, other]

Title: Predicting the 21 cm field with a Hybrid Effective Field Theory approach

Danial Baradaran, Boryana Hadzhiyska, Martin J. White, Noah Sailer

Comments: 14 pages, 11 figures, submitted to PRD

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

A detection of the 21 cm signal can provide a unique window of opportunity for uncovering complex astrophysical phenomena at the epoch of reionization and placing constraints on cosmology at high redshifts, which are usually elusive to large-scale structure surveys. In this work, we provide a theoretical model based on a quadratic bias expansion capable of recovering the 21 cm power spectrum with high accuracy sufficient for upcoming ground-based radio interferometer experiments. In particular, we develop a hybrid effective field theory (HEFT) model in redshift space that leverages the accuracy of $N$-body simulations with the predictive power of analytical bias expansion models, and test it against the Thesan suite of radiative transfer hydrodynamical simulations. We make predictions of the 21 cm brightness temperature field at several distinct redshifts, ranging between $z = 6.5$ and 11, thus probing a large fraction of the reionization history of the Universe ($x_{\rm HI} = 0.3 \sim 0.9$), and compare our model to the `true' 21 cm brightness in terms of the correlation coefficient, power spectrum and modeling error. We find percent-level agreement at large and intermediate scales, $k \lesssim 0.5 h/{\rm Mpc}$, and favorable behavior down to small scales, $k \sim 1 h/{\rm Mpc}$, outperforming pure perturbation-theory-based models. To put our findings into context, we show that even in the absence of any foreground contamination the thermal noise of a futuristic HERA-like experiment is comparable with the theoretical uncertainty in our model in the allowed `wedge' of observations, providing further evidence in support of using HEFT-based models to approximate a range of cosmological observables.

[23] arXiv:2406.13623 (cross-list from astro-ph.HE) [pdf, html, other]

Title: Revealing the burning and soft heart of the bright bare AGN ESO 141-G55: X-ray broadband and SED analysis

Delphine Porquet, James N. Reeves, Scott Hagen, Andrew Lobban, Valentina Braito, Nicolas Grosso, Frédéric Marin

Comments: 16 pages, 14 figures, 3 appendices; accepted for publication in Astronomy & Astrophysics

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

[Abridged] ESO 141-G55 is a nearby X-ray bright BLS1, which has been classified as a bare AGN due to the lack of warm absorption along its line-of-sight, providing an unhampered view into its disc-corona system. We aim to probe its disc-corona system thanks to the first simultaneous XMM-Newton and NuSTAR observation obtained on October 1-2, 2022. We carry out the X-ray broadband spectral analysis to determine the dominant process(es) at work, as well as the SED analysis to determine the disc-corona properties. The simultaneous broadband X-ray spectrum of ESO 141-G55 is characterised by the presence of a prominent smooth soft X-ray excess, a broad Fe K emission line and a significant Compton hump. The RGS spectra confirmed the lack of intrinsic warm-absorbing gas along our line of sight in the AGN rest frame, confirming that it is still in a bare state. However, soft X-ray emission lines are observed indicating substantial warm gas out of our line of sight. The intermediate inclination of the disc-corona system, ~43°, may offer us a favourable configuration to observe UFOs from the disc, but none is found in this 2022 observation, contrary to a previous 2007 XMM-Newton one. Relativistic reflection alone on a standard disc is ruled out from the X-ray broadband analysis, while a combination of soft and hard Comptonisation by a warm and hot corona (relagn), plus relativistic reflection (reflkerrd) reproduces its SED quite well. The hot corona temperature is very hot, ~140 keV, much higher than about 80% of the AGNs, whereas the warm corona temperature, ~0.3 keV, is similar to the values found in other sub-Eddington AGNs. ESO 141-G55 is accreting at a moderate Eddington accretion rate (~10--20%). Our analysis points to a significant contribution of an optically-thick warm corona to both the soft X-ray and UV emission in ESO 141-G55.

[24] arXiv:2406.13736 (cross-list from astro-ph.CO) [pdf, html, other]

Title: Constraining cosmological parameters using void statistics from the SDSS survey

Elena Fernández-García, Juan E. Betancort-Rijo, Francisco Prada, Tomoaki Ishiyama, Anatoly Klypin

Comments: 22 pages, 18 figures. All data sets are made publicly available in this https URL

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

We identify voids as maximal non-overlapping spheres within the haloes of the Uchuu simulation and three smaller halo simulation boxes with smaller volume and different $\sigma_{8}$ values, and galaxies with redshift in the range $0.02<z<0.132$ and absolute magnitude in the $r-$band $M_{r}<-20.5$ of 32 Uchuu-SDSS simulated lightcones the seventh release of \textit{The Sloan Digital Sky Survey} (SDSS DR7) survey. We compute the Void Probability Function and the abundance of voids larger than $r$ predicted by the theoretical framework used in this work and we check that it predicts successfully both void functions for the halo simulation boxes. Next, we asses the potential of this theoretical framework to constrain cosmological parameters using Uchuu-SDSS void statistics, and we calculate the confidence levels using Monte Carlo Markov Chain techniques to infer the values of $\sigma_{8}$, $\Omega_{\rm m}$ and H$_{0}$ from the SDSS sample used. The constraints we obtain from the SDSS survey sample used. The results are: $\sigma_{8}=1.028^{+0.273}_{-0.305}$, $\Omega_{\rm m}=0.296^{+0.110}_{-0.102}$, H$_{0}=83.43\pm^{+29.27}_{-27.70}$, $\Gamma=0.1947^{+0.0578}_{-0.0516}$ and S$_{8}$=1.017$^{+0.363}_{-0.359}$. If we combine these constraints with KiDS-1000+DESY3, we get $\sigma_{8}=0.858^{+0.040}_{-0.040}$, $\Omega_{\rm m}=0.257\pm^{+0.023}_{-0.020}$, H$_{0}=74.17^{+4.66}_{-4.66}$ and S$_{8}$=0.794$^{+0.016}_{-0.016}$. The combined uncertainties are approximately a factor 2-3 smaller than only-Weak-Lensing uncertainties. This is a consequence of the orientation of the confidence level contours of SDSS voids and Weak Lensing in the plane $\sigma_{8}-\Omega_{\rm m}$, which are almost orthogonal (abridged).

[25] arXiv:2406.13757 (cross-list from astro-ph.SR) [pdf, html, other]

Title: Magnetic Fields of M Dwarfs from the Pleiades Open Cluster

Fabio Wanderley, Katia Cunha, Oleg Kochukhov, Verne V. Smith, Diogo Souto, Lyra Cao, Kevin Covey, Steven R. Majewski, Cintia Martinez, Philip S. Muirhead, Marc Pinsonneault, C. Allende Prieto, Keivan G. Stassun

Comments: Accepted for publication by The Astrophysical Journal (ApJ); doi:https://doi.org/10.3847/1538-4357/ad571f

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

Average magnetic field measurements are presented for 62 M-dwarf members of the Pleiades open cluster, derived from Zeeman-enhanced Fe I lines in the H-band. An MCMC methodology was employed to model magnetic filling factors using SDSS-IV APOGEE high-resolution spectra, along with the radiative transfer code SYNMAST, MARCS stellar atmosphere models, and the APOGEE DR17 spectral line list. There is a positive correlation between mean magnetic fields and stellar rotation, with slow-rotator stars (Rossby number, Ro$>$0.13) exhibiting a steeper slope than rapid-rotators (Ro$<$0.13). However, the latter sample still shows a positive trend between Ro and magnetic fields, which is given by $<$B$>$ = 1604 $\times$ Ro$^{-0.20}$. The derived stellar radii, when compared with physical isochrones, show that on average, our sample shows radius inflation, with median enhanced radii ranging from +3.0$\%$ to +7.0$\%$, depending on the model. There is a positive correlation between magnetic field strength and radius inflation, as well as with stellar spot coverage, correlations that together indicate that stellar spot-filling factors generated by strong magnetic fields might be the mechanism that drives radius inflation in these stars. We also compare our derived magnetic fields with chromospheric emission lines (H$\alpha$, H$\beta$ and Ca II K), as well as with X-ray and H$\alpha$ to bolometric luminosity ratios, and find that stars with higher chromospheric and coronal activity tend to be more magnetic.

[26] arXiv:2406.13786 (cross-list from astro-ph.HE) [pdf, html, other]

Title: Galaxy-group-associated distances to Very High Energy gamma-ray emitting BL Lacs KUV 00311-1938 and S2 0109+22

Karri I. I. Koljonen, Elina Lindfors, Kari Nilsson, Pekka Heinämäki, Jari Kotilainen

Comments: 11 pages, 8 figures, 3 tables. This article has been accepted for publication in MNRAS published by Oxford University Press on behalf of the Royal Astronomical Society

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)

Blazars constitute the most numerous source class in the known extragalactic population of very high energy (VHE) gamma-ray sources. However, determining their redshifts is often challenging due to weak or non-existent emission lines in their spectra. This study focuses on two BL Lacs, KUV 00311-1938 and S2 0109+22, where previous attempts at redshift determination have faced difficulties. By combining spectroscopic observations with photometric redshift estimates, we tentatively assign a redshift of z = 0.634 to KUV 00311-1938 and a likely redshift of z = 0.49 to S2 0109+22. Establishing redshift estimates for high-redshift blazars is crucial for understanding extragalactic VHE gamma-ray sources and their interactions with the surrounding universe.

[27] arXiv:2406.13914 (cross-list from astro-ph.IM) [pdf, html, other]

Title: The Blue Multi Unit Spectroscopic Explorer (BlueMUSE) on the VLT: science drivers and overview of instrument design

Johan Richard, Rémi Giroud, Florence Laurent, Davor Krajnović, Alexandre Jeanneau, Roland Bacon, Manuel Abreu, Angela Adamo, Ricardo Araujo, Nicolas Bouché, Jarle Brinchmann, Zhemin Cai, Norberto Castro, Ariadna Calcines, Diane Chapuis, Adélaïde Claeyssens, Luca Cortese, Emanuele Daddi, Christopher Davison, Michael Goodwin, Robert Harris, Matthew Hayes, Mathilde Jauzac, Andreas Kelz, Jean-Paul Kneib, Audrey A. Lanotte, Jon Lawrence, Vianney Le Bouteiller, Rémy Le Breton, Matthew Lehnert, Angel Lopez Sanchez, Helen McGregor, Anna F. McLeod, Manuel Monteiro, Simon Morris, Cyrielle Opitom, Arlette Pécontal, David Robertson, Jesse van de Sande, Russell Smith, Matthias Steinmetz, Mark Swinbank, Tanya Urrutia, Anne Verhamme, Peter M. Weilbacher, Martin Wendt, François Wildi, Jessica Zheng, The BlueMUSE consortium

Comments: 20 pages, 10 figures, proceedings of the SPIE astronomical telescopes and instrumentation conference, Yokohama, 16-21 June

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)

BlueMUSE is a blue-optimised, medium spectral resolution, panoramic integral field spectrograph under development for the Very Large Telescope (VLT). With an optimised transmission down to 350 nm, spectral resolution of R$\sim$3500 on average across the wavelength range, and a large FoV (1 arcmin$^2$), BlueMUSE will open up a new range of galactic and extragalactic science cases facilitated by its specific capabilities. The BlueMUSE consortium includes 9 institutes located in 7 countries and is led by the Centre de Recherche Astrophysique de Lyon (CRAL). The BlueMUSE project development is currently in Phase A, with an expected first light at the VLT in 2031. We introduce here the Top Level Requirements (TLRs) derived from the main science cases, and then present an overview of the BlueMUSE system and its subsystems fulfilling these TLRs. We specifically emphasize the tradeoffs that are made and the key distinctions compared to the MUSE instrument, upon which the system architecture is built.

[28] arXiv:2406.13986 (cross-list from astro-ph.SR) [pdf, html, other]

Title: Novae: An Important Source of Lithium in the Galaxy

Jun Gao, Chunhua Zhu, Guoliang Lü, Jinlong Yu, Lin Li, Helei Liu, Sufen Guo

Comments: 12 pages, 4 figures. Accepted for publication in Astrophysical Journal

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

The source of the Galactic Lithium (Li) has long been a puzzle. With the discovery of Li in novae, extensive research has been conducted. However, there still exists a significant disparity between the observed abundance of lithium in novae and the existing theoretical predictions. Using the Modules for Experiments in Stellar Astrophysics (MESA), we simulate the evolution of nova with element diffusion and appropriately increased the amount of 3^He in the mixtures. Element diffusion enhances the transport efficiency between the nuclear reaction zone and the convective region on the surface of the white dwarf during nova eruptions, which results in more 7^Be to be transmitted to the white dwarf surface and ultimately ejected. Compared to the previous predictions, the abundance of 7^Be in novae simulated in our model significantly increases. And the result is able to explain almost all observed novae. Using the method of population synthesis, we calculate Li yield in the Galaxy. We find that the Galactic occurrence rate of nova is about 130 yr^{-1}, and about 110M Li produced by nova eruption is ejected into the interstellar medium (ISM). About 73\% of Li in the Galactic ISM originates from novae, and approximately 15\%-20\% of the entire Galaxy. It means that novae are the important source of Li in the Galactic.

[29] arXiv:2406.14157 (cross-list from gr-qc) [pdf, html, other]

Title: Exact solutions for differentially rotating galaxies in general relativity

Marco Galoppo, David L. Wiltshire

Comments: 5 pages, 2 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

A class of stationary axisymmetric solutions of Einstein's equations for isolated differentially rotating dust sources is presented. The low-energy asymptotic regime is extracted, requiring a self-consistent coupling of quasilocal energy and angular momentum. The Raychaudhuri equation reduces to a balance equation, with two important limits. These limits can be interpreted empirically for rotationally supported configurations such as galaxies. The net energy including quasilocal kinetic contributions vanishes on the inner vortex surface, and the outer rotosurface. These new geometrical objects potentially shed light on virialization. Whether or not abundant collisionless dark matter exists, the new solutions suggest that the phenomenology of galactic rotation curves be fundamentally reconsidered, for consistency with general relativity.

[30] arXiv:2406.14195 (cross-list from astro-ph.HE) [pdf, html, other]

Title: Investigating the Role of Pre-supernova Massive Stars in the Acceleration of Galactic Cosmic Rays

Michael De Becker, Santiago del Palacio, Paula Benaglia, Anandmayee Tej, Benito Marcote, Gustavo Esteban Romero, Valenti Bosch-Ramon, C. H. Ishwara-Chandra

Comments: 8 pages, 1 figure, Published in the Proceedings of the 3rd BINA Workshop on the Scientific Potential of the Indo-Belgian Cooperation

Journal-ref: Bulletin de la Soci\'et\'e Royale des Sciences de Li\`ege, 2024, Volume 93, No 2, 536-543

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

Galactic cosmic rays (GCRs) constitute a significant part of the energy budget of our Galaxy, and the study of their accelerators is of high importance in modern astrophysics. Their main sources are likely supernova remnants (SNRs). These objects are capable to convert a part of their mechanical energy into accelerated charged particles. However, even though the mechanical energy reservoir of SNRs is promising, a conversion rate into particle energy of 10 to 20% is necessary to feed the population of GCRs. Such an efficiency is however not guaranteed. Complementary sources deserve thus to be investigated. This communication aims to address the question of the contribution to the acceleration of GCRs by pre-supernova massive stars in binary or higher multiplicity systems

[31] arXiv:2406.14531 (cross-list from astro-ph.EP) [pdf, html, other]

Title: Roman FFP Revolution: Two, Three, Many Plutos

Andrew Gould (OSU, MPIA), Jennifer C. Yee (CfA), Subo Dong (PKU, Kavli)

Comments: 46 pages, 4 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Roman microlensing stands at a crossroads between its originally charted path of cataloging a population of cool planets that has subsequently become well-measured down to super-Earths, and the path of free-floating planets (FFPs), which did not exist when Roman was chosen in 2010, but by now promises revolutionary insights into planet formation and evolution via their possible connection to a spectrum of objects spanning 18 decades in mass. Until now, it was not even realized that the 2 paths are in conflict: Roman strategy was optimized for bound-planet detections, and FFPs were considered only in the context of what could be learned about them given this strategy. We derive a simple equation that mathematically expresses this conflict and explains why the current approach severely depresses detection of 2 of the 5 decades of potential FFP masses, i.e., exactly the two decades, $M_{\rm Pluto}< M <2\,M_{\rm Mars}$, that would tie terrestrial planets to the proto-planetary material out of which they formed. FFPs can be either truly free floating or can be bound in "Wide", "Kuiper", and "Oort" orbits, whose separate identification will allow further insight into planet formation. In the (low-mass) limit that the source radius is much bigger than the Einstein radius, $\theta_*\gg\theta_{\rm E}$, the number of significantly magnified points on the FFP light curve is $N=2\Gamma\theta_*\sqrt{1-z^2}/\mu$ --> 3.0, when normalized to the adopted Roman cadence $\Gamma=4/$hr, and to source radius $\theta_*=0.3\,\mu$as, lens-source proper motion $\mu=6\,$mas/yr, and source impact parameter $z=0.5$, which are all typical values. By contrast $N=6$ are needed for an FFP detection. Thus, unless $\Gamma$ is doubled, FFP detection will be driven into the (large-$\theta_*$, small-$\mu$) corner of parameter space, reducing the detections by a net factor of 2 and cutting off the lowest-mass FFPs.

Replacement submissions for Friday, 21 June 2024 (showing 26 of 26 entries )

[32] arXiv:2208.08443 (replaced) [pdf, html, other]

Title: A stream come true: Connecting tidal tails, shells, streams, and planes with galaxy kinematics and formation history

Lucas M. Valenzuela, Rhea-Silvia Remus

Comments: 12 pages, 7 figures, published in A&A

Journal-ref: A&A 686, A182 (2024)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The rapidly improving quality and resolution of both low surface brightness observations and cosmological simulations of galaxies enables one to address the important question how the formation history is imprinted in the outer, unrelaxed regions of galaxies, and to inspect the correlations of such imprints with the internal kinematics. Using the hydrodynamical cosmological simulation Magneticum Pathfinder, we identify tidal tails, shells, streams, and satellite planes, and connect their existence to the amount of rotational support and the formation histories of the host galaxies. This presents the first combined statistical census considering all those four types of features in hydrodynamical cosmological simulations. Tidal features are visually classified from a 3D rendering of the simulated galaxies by several scientists. The results are compared to observations, especially from the MATLAS survey. Prominent features are more common around elliptical than around disk galaxies. Shells are preferentially found around kinematically slowly rotating galaxies in both simulations and observations, while streams only have a slight preference to be present around slowly rotating galaxies. Tails and satellite planes appear independently of the internal kinematics of the central galaxy, indicating that they are formed through processes that have not (yet) affected the internal kinematics. As shells are formed through radial merger events while streams are remnants of circular merger infall, this suggests that the orbital angular momentum of the merger event plays a more crucial role in transforming the host galaxy than previously anticipated. The existence of shells around slow rotators is further a sign of a radial merger formation for the particular slow rotators, as a third of the galaxies with a shell were transformed into slow rotators by the merger event that also caused the shells.

[33] arXiv:2309.11545 (replaced) [pdf, html, other]

Title: Galaxy archaeology for wet mergers: Globular cluster age distributions in the Milky Way and nearby galaxies

Lucas M. Valenzuela, Rhea-Silvia Remus, Madeleine McKenzie, Duncan A. Forbes

Comments: 18 pages, 14 figures, accepted for publication in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Identifying past wet merger activity in galaxies has been a longstanding issue in extragalactic formation history studies. Gaia's 6D kinematic measurements in our Milky Way (MW) have vastly extended the possibilities for Galactic archaeology, leading to the discovery of early mergers in the MW's past. As recent work has established a link between young globular clusters (GCs) and wet galaxy merger events, the MW provides an ideal laboratory for testing how GCs can be used to trace galaxy formation histories. To test the hypothesis that GCs trace wet mergers, we relate the measured GC age distributions of the MW and three nearby galaxies to their merger histories and interpret the connection with wet mergers through an empirical model for GC formation. For the MW, we cross-match the GCs with their associated progenitor host galaxies to disentangle the connection to the GC age distribution. We find that the MW GC age distribution is bimodal, mainly caused by younger GCs associated with Gaia-Sausage/Enceladus (GSE) and in part by unassociated high-energy GCs. The GSE GC age distribution also appears to be bimodal. We propose that the older GSE GCs were accreted together with GSE, while the younger ones formed through the merger. For the nearby galaxies, we find that peaks in the GC age distributions coincide with early gas-rich mergers. Even small signatures in the GC age distributions agree well with the formation histories of the galaxies inferred through other observed tracers. From the models, we predict that the involved cold gas mass can be estimated from the number of GCs found in the formation burst. Multimodal GC age distributions can trace massive wet mergers as a result of GCs being formed through them. From the laboratory of our own MW and nearby galaxies we conclude that the ages of younger GC populations of galaxies can be used to infer the wet merger history of a galaxy.

[34] arXiv:2310.18817 (replaced) [pdf, html, other]

Title: Low-redshift Lyman Continuum Survey: Radio continuum properties of low-$z$ Lyman continuum emitters

Omkar Bait, Sanchayeeta Borthakur, Daniel Schaerer, Emmanuel Momjian, Biny Sebastian, Alberto Saldana-Lopez, Sophia R. Flury, John Chisholm, Rui Marques-Chaves, Anne E. Jaskot, Harry C. Ferguson, Gabor Worseck, Zhiyuan Ji, Lena Komarova, Maxime Trebitsch, Matthew J. Hayes, Laura Pentericci, Goran Ostlin, Trinh Thuan, Ricardo O. Amorín, Bingjie Wang, Xinfeng Xu, Mark T. Sargent

Comments: 20 pages, 17 figures, 4 tables, 8 appendix pages, Astronomy & Astrophysics in press

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Sources that leak Lyman-continuum (LyC) photons and lead to the reionisation of the universe are intensely studied using multiple observing facilities. Recently, the Low-redshift LyC Survey (LzLCS) has found the first large sample of LyC emitting galaxies at low redshift ($z\sim 0.3$) with the Hubble Space Telescope/Cosmic Origins Spectrograph. The LzLCS sample contains a robust estimate of the LyC escape fraction ($f_\mathrm{esc}^\mathrm{LyC}$) for 66 galaxies spanning a wide range of $f_\mathrm{esc}^\mathrm{LyC}$. Here we, for the first time, aim to study the radio continuum (RC) properties of LzLCS sources and their dependence on $f_\mathrm{esc}^\mathrm{LyC}$. We present Karl G. Jansky Very Large Array RC observations at C (4-8 GHz), S (2-4 GHz) and L (1-2 GHz) bands for a sub-sample of the LzLCS sources. The radio spectral index ($\alpha^{\mathrm{3GHz}}_\mathrm{6GHz}$) spans a wide range from being flat ( $\geq -0.1$) to very steep ($\leq -1.0$). The strongest leakers in our sample show flat $\alpha^{\mathrm{3GHz}}_\mathrm{6GHz}$, weak leakers have $\alpha^{\mathrm{3GHz}}_\mathrm{6GHz}$ close to normal star-forming galaxies, and non-leakers are characterized by steep $\alpha^{\mathrm{3GHz}}_\mathrm{6GHz}$. We argue that a combination of young ages, free-free absorption, and a flat cosmic-ray energy spectrum can altogether lead to a flat $\alpha^{\mathrm{3GHz}}_\mathrm{6GHz}$ for strong leakers. Non-leakers are characterized by steep spectra which can arise due to break/cutoff at high frequencies. Such a cutoff in the spectrum can arise in a single injection model of CRs characteristic of galaxies which have recently stopped star formation. Such a relation between $\alpha^{\mathrm{3GHz}}_\mathrm{6GHz}$ and $f_\mathrm{esc}^\mathrm{LyC}$ hints at the interesting role of supernovae, CRs, and magnetic fields in facilitating the escape ( and/or the lack) of LyC photons. (Abridged)

[35] arXiv:2311.02051 (replaced) [pdf, html, other]

Title: Nebular dominated galaxies: insights into the stellar initial mass function at high redshift

Alex J. Cameron, Harley Katz, Callum Witten, Aayush Saxena, Nicolas Laporte, Andrew J. Bunker

Comments: 22 pages, 17 Figures, accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We identify a low-metallicity ($12+\log({\rm O}/{\rm H})=7.59$) Ly$\alpha$-emitting galaxy at $z=5.943$ with evidence of a strong Balmer jump, arising from nebular continuum. While Balmer jumps are sometimes observed in low-redshift star-forming galaxies, this galaxy also exhibits a steep turnover in the UV continuum. Such turnovers are typically attributed to absorption by a damped Ly$\alpha$ system (DLA); however, the shape of the turnover and the high observed Ly$\alpha$ escape fraction ($f_{\rm esc,Ly\alpha}~\sim27\%$) is also consistent with strong nebular two-photon continuum emission. Modelling the UV turnover with a DLA requires extreme column densities ($N_{\rm HI}>10^{23}$ cm$^{-2}$), and simultaneously explaining the high $f_{\rm esc,Ly\alpha}$ requires a fine-tuned geometry. In contrast, modelling the spectrum as primarily nebular provides a good fit to both the continuum and emission lines, motivating scenarios in which (a) we are observing only nebular emission or (b) the ionizing source is powering extreme nebular emission that outshines the stellar emission. The nebular-only scenario could arise if the ionising source has `turned off' more recently than the recombination timescale ($\sim$1,000 yr), hence we may be catching the object at a very specific time. Alternatively, hot stars with $T_{\rm eff}\gtrsim10^5$ K (e.g. Wolf-Rayet or low-metallicity massive stars) produce enough ionizing photons such that the two-photon emission becomes visible. While several stellar SEDs from the literature fit the observed spectrum well, the hot-star scenario requires that the number of $\gtrsim50~{\rm M}_\odot$ stars relative to $\sim5-50~{\rm M}_\odot$ stars is significantly higher than predicted by typical stellar initial mass functions (IMFs). The identification of more galaxies with similar spectra may provide evidence for a top-heavy IMF at high redshift.

[36] arXiv:2311.02297 (replaced) [pdf, html, other]

Title: Candidate Members of the VMP/EMP Disk System of the Galaxy from the SkyMapper and SAGES Surveys

Jihye Hong, Timothy C. Beers, Young Sun Lee, Yang Huang, Yutaka Hirai, Jonathan Cabrera Garcia, Derek Shank, Shuai Xu, Haibo Yuan, Mohammad K. Mardini, Thomas Catapano, Gang Zhao, Zhou Fan, Jie Zheng, Wei Wang, Kefeng Tan, Jingkun Zhao, Chun Li

Comments: It is now accepted to the ApJS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target-selection biases often associated with such studies. Photometric-metallicity estimates that include narrow/medium-band filters can achieve comparable accuracy and precision to existing low-resolution spectroscopic surveys such as SDSS/SEGUE and LAMOST. Here we report on an effort to identify likely members of the Galactic disk system among the very metal-poor (VMP; [Fe/H] $\leq$ --2) and extremely metal-poor (EMP; [Fe/H] $\leq$ --3) stars. Our analysis is based on an initial sample of $\sim11.5$ million stars with full space motions selected from the SkyMapper Southern Survey (SMSS) and Stellar Abundance and Galactic Evolution Survey (SAGES). After applying a number of quality cuts to obtain the best available metallicity and dynamical estimates, we analyze a total of $\sim$5.86 million stars in the combined SMSS/SAGES sample. We employ two techniques that, depending on the method, identify between 876 and 1,476 VMP stars (6.9%-11.7% of all VMP stars) and between 40 and 59 EMP stars (12.4%-18.3% of all EMP stars) that appear to be members of the Galactic disk system on highly prograde orbits (v$_{\phi} > 150$ km/s). The total number of candidate VMP/EMP disk-like stars is 1,496, the majority of which have low orbital eccentricities, ecc $\le 0.4$; many have ecc $\le 0.2$. The large fractions of VMP/EMP stars associated with the Milky Way disk system strongly suggest the presence of an early forming ``primordial" disk.

[37] arXiv:2402.05720 (replaced) [pdf, html, other]

Title: Measurements of the Low-Acceleration Gravitational Anomaly from the Normalized Velocity Profile of Gaia Wide Binary Stars and Statistical Testing of Newtonian and Milgromian Theories

Kyu-Hyun Chae

Comments: 36 pages, 27 figures, 4 tables, ApJ, revised (Sections 2.1 & 3.4 expanded, Appendix B added)

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

Low-acceleration gravitational anomaly is investigated with a new method of exploiting the normalized velocity profile $\tilde{v}\equiv v_p/v_c$ of wide binary stars as a function of the normalized sky-projected radius $s/r_{\rm{M}}$ where $v_p$ is the sky-projected relative velocity between the pair, $v_c$ is the Newtonian circular velocity at the sky-projected separation $s$, and $r_{\rm{M}}$ is the MOND radius. With a Monte Carlo method Gaia observed binaries and their virtual Newtonian counterparts are probabilistically distributed on the $s/r_{\rm{M}}$ versus $\tilde{v}$ plane and a logarithmic velocity ratio parameter $\Gamma$ is measured in the bins of $s/r_{\rm{M}}$. With three samples of binaries covering a broad range in size, data quality, and implied fraction of hierarchical systems including a new sample of 6389 binaries selected with accurate distances and radial velocities, I find a unanimous systematic variation from the Newtonian flat line. With $\Gamma=0$ at $s/r_{\rm{M}}\lesssim 0.15$ or $s\lesssim 1$~kilo astronomical units (kau), I get $\Gamma=0.068\pm 0.015$ (stat) $_{-0.015}^{+0.024}$ (syst) for $s/r_{\rm{M}} \gtrsim 0.7$ or $s\gtrsim 5$~kau. The gravitational anomaly (i.e.\ acceleration boost) factor given by $\gamma_g = 10^{2\Gamma}$ is measured to be $\gamma_g = 1.37_{-0.09}^{+0.10}$ (stat) $_{-0.09}^{+0.16}$ (syst). With a reduced $\chi^2$ test of Newtonian and Milgromian nonrelativistic theories, I find that Newtonian gravity is ruled out at $5.8\sigma$ ($\chi^2_\nu=9.4$) by the new sample (and $9.2\sigma$ by the largest sample used). The Milgromian AQUAL theory is acceptable with $0.5\lesssim \chi^2_\nu\lesssim 3.1$. These results agree well with earlier results with the "acceleration-plane analysis" for a variety of samples and the "stacked velocity profile analysis" for a pure binary sample.

[38] arXiv:2402.13316 (replaced) [pdf, html, other]

Title: Dead or Alive? How Bursty Star Formation and Patchy Dust Can Cause Temporary Quiescence in High Redshift Galaxies

A. L. Faisst, T. Morishita

Comments: 8 pages, 5 figures. Accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The recent discovery of a galaxy at z=7.3 with undetected optical emission lines and a blue UV to optical continuum ratio in JWST spectroscopy is surprising and needs to be explained physically. Here, we explore two possibilities that could cause such a seemingly quiescent ~5e8 $\rm M_\odot$ galaxy in the early Universe: (i) stochastic variations in the star formation history (SFH) and (ii) the effect of spatially varying dust attenuation on the measured line and continuum emission properties. Both scenarios can play at the same time to amplify the effect. A stochastic star formation model (similar to realistic SFHs from hydrodynamical simulations of similar-mass galaxies) can create such observed properties if star formation is fast-varying with a correlation time of <150 Myrs given a reasonable burst amplitude of ~0.6 dex. The total time spent in this state is less than 20 Myrs and the likelihood of such a state to occur over 500 Myrs at z=7 is ~50% (consistent with current observations). On the other hand, we show that a spectrum with blue UV continuum and lack of emission lines can be reproduced by a blue+red composite spectrum. The UV continuum is emitted from dust-free density bounded HII regions (blue component), while the red component is a dust-obscured starburst with weakened emission lines due to strong differential dust attenuation between stellar and nebular emission. Future resolving far-infrared observations with ALMA will shed light on the latter scenario.

[39] arXiv:2402.16649 (replaced) [pdf, html, other]

Title: A Strongly Lensed Dusty Starburst of an Intrinsic Disk Morphology at Photometric Redshift of 7.7

Chenxiaoji Ling, Bangzheng Sun, Cheng Cheng, Nan Li, Zhiyuan Ma, Haojing Yan

Comments: 27 pages, 12 figures. ApJL accepted

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present COSBO-7, a strong millimeter (mm) source known for more than sixteen years but was just revealed its near-to-mid-IR counterpart by the James Webb Space Telescope (JWST). The precise pin-pointing by the Atacama Large Millimeter Array (ALMA) on the exquisite NIRCam and MIRI images show that it is a background source gravitationally lensed by a single foreground galaxy, and the analysis of its spectral energy distribution by different tools consistently derives its photometric redshift at $\sim$7.7. Strikingly, our lens modeling based on the JWST data shows that it has a regular, disk morphology in the source plane. The dusty region giving rise to the far-IR-to-mm emission seems to be confined to a limited region to one side of the disk and has a high dust temperature of $>90$~K. The galaxy is experiencing starburst both within and outside of this dusty region. After taking the lensing magnification of $\mu\approx 2.5\mbox{-}3.6$ into account, the intrinsic star formation rate is several hundred $M_\odot$ yr$^{-1}$ both within the dusty region and across the more extended stellar disk, and the latter already has $>10^{10}M_\odot$ of stars in place. If all this is true, COSBO-7 presents an extraordinary case that is against the common wisdom about galaxy formation in the early universe; simply put, its existence poses a critical question to be answered: how could a massive disk galaxy come into being so early in the universe and sustain its regular morphology in the middle of an enormous starburst?

[40] arXiv:2402.17829 (replaced) [pdf, html, other]

Title: The evolution of the SFR and Sigma-SFR of galaxies in cosmic morning (4 < z < 10)

A. Calabrò, L. Pentericci, P. Santini, A. Ferrara, M. Llerena, S. Mascia, L. Napolitano, L.Y.A. Yung, L. Bisigello, M.Castellano, N.J. Cleri, A. Dekel, M. Dickinson, M. Franco, M. Giavalisco, M. Hirschmann, B.W. Holwerda, A.M. Koekemoer, R.A. Lucas, F. Pacucci, N. Pirzkal, G. Roberts-Borsani, L.M. Seillé, S. Tacchella, S. Wilkins, R. Amorín, P. Arrabal Haro, M.B. Bagley, S.L. Finkelstein, J.S. Kartaltepe, C. Papovich

Comments: Accepted for publication in A&A ; 19 pages, 9 figures, 1 table. Compared to the previous version, we have corrected a typo in Fig. 5 (the x and y axis labels were inverted)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The galaxy integrated star-formation rate (SFR) surface density ($\Sigma_{\rm SFR}$) has been proposed as a valuable diagnostic of the mass accumulation in galaxies as being more tightly related to the physics of star-formation (SF) and stellar feedback than other SF indicators. In this paper, we assemble a statistical sample of 230 galaxies observed with JWST in the GLASS and CEERS spectroscopic surveys to estimate Balmer line based dust attenuations and SFRs, and UV rest-frame effective radii. We study the evolution of galaxy SFR and $\Sigma_{\rm SFR}$ in the first 1.5 Billion years of our Universe, finding that $\Sigma_{\rm SFR}$ is mildly increasing with redshift with a linear slope of $0.16 \pm 0.06$. We also explore the dependence of SFR and $\Sigma_{\rm SFR}$ on stellar mass, showing that a SF 'Main-Sequence' and a $\Sigma_{\rm SFR}$ `Main-Sequence' are in place out to z=10, with a similar slope compared to the same relations at lower redshifts. We find that the specific SFR (sSFR) and $\Sigma_{\rm SFR}$ are correlated with the [OIII]5007/[OII]3727 ratio and with indirect estimates of the escape fraction of Lyman continuum photons, hence they likely play an important role in the evolution of ionization conditions and in the escape of ionizing radiation. We also search for spectral outflow signatures in a subset of galaxies observed at high resolution, finding an outflow incidence of $2/11$ ($=20\%^{32\%}_{9\%}$) at $z<6$, but no evidence at $z>6$ ($<26\%$). Finally, we find a positive correlation between A$_V$ and $\Sigma_{\rm SFR}$, and a flat trend as a function of sSFR, indicating that there is no evidence of a drop of A$_V$ in extremely star-forming galaxies between z=4 and 10. This might be at odds with a dust-clearing outflow scenario, which might instead take place at redshifts $z\geq 10$, as suggested by some theoretical models.

[41] arXiv:2403.04274 (replaced) [pdf, html, other]

Title: Relative alignment between gas structures and magnetic field in Orion A at different scales using different molecular gas tracers

Wenyu Jiao, Ke Wang, Fengwei Xu, Chao Wang, Henrik Beuther

Comments: 12 pages, 8 figures, published in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

Context: Magnetic fields can play crucial roles in high-mass star formation. Nonetheless, the significance of magnetic fields at various scales and their relationship with gas structures is largely overlooked. Aims: Our goal is to examine the relationship between the magnetic field and molecular gas structures within the Orion A giant molecular cloud at different scales and density regimes. Methods: We assess the gas intensity structures and column densities in Orion A by utilizing $^{12}$CO, $^{13}$CO, and C$^{18}$O from Nobeyama observations. Through comparing Nobeyama observations with {\it{Planck}} polarization observations on large scales ($\sim0.6$ pc) and JCMT polarization observations on small scales ($\sim0.04$ pc), we investigate how the role of magnetic fields change with scale and density. Results: We find a similar trend from parallel to perpendicular alignment with increasing column densities in Orion A at both large and small spatial scales. Besides, when changing from low-density to high-density tracers, the relative orientation preference changes from random to perpendicular. The self-similar results at different scales indicate that magnetic fields are dynamically important in both cloud formation and filament formation. However, magnetic fields properties at small scales are relative complicated, and the interplay between magnetic field and star-forming activities needs to be discussed case-by-case.

[42] arXiv:2404.06569 (replaced) [pdf, html, other]

Title: Ly$\alpha$ Emission Line Profiles of Extreme [OIII] Emitting Galaxies at $z\gtrsim2$: Implications for Ly$\alpha$ Visibility in the Reionization Era

Mengtao Tang, Daniel P. Stark, Richard S. Ellis, Michael W. Topping, Charlotte Mason, Zhihui Li, Adèle Plat

Comments: 28 pages, 11 figures, accepted by ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

JWST observations have recently begun delivering the first samples of Ly$\alpha$ velocity profile measurements at $z>6$, opening a new window on the reionization process. Interpretation of $z\gtrsim6$ line profiles is currently stunted by limitations in our knowledge of the intrinsic Ly$\alpha$ profile (before encountering the IGM) of the galaxies that are common at $z\gtrsim6$. To overcome this shortcoming, we have obtained resolved ($R\sim3900$) Ly$\alpha$ spectroscopy of $42$ galaxies at $z=2.1-3.4$ with similar properties as are seen at $z>6$. We quantify a variety of Ly$\alpha$ profile statistics as a function of [OIII]+H$\beta$ EW. Our spectra reveal a new population of $z\simeq 2-3$ galaxies with large [OIII]+H$\beta$ EWs ($>1200\ Å$) and a large fraction of Ly$\alpha$ flux emerging near the systemic redshift (peak velocity $\simeq0$ km s$^{-1}$). These spectra indicate that low density neutral hydrogen channels are able to form in a subset of low mass galaxies ($\lesssim1\times10^8\ M_{\odot}$) that experience a burst of star formation (sSFR $>100$ Gyr$^{-1}$). Other extreme [OIII] emitters show weaker Ly$\alpha$ that is shifted to higher velocities ($\simeq240$ km s$^{-1}$) with little emission near line center. We investigate the impact the IGM is likely to have on these intrinsic line profiles in the reionization era, finding that the centrally peaked Ly$\alpha$ emitters should be strongly attenuated at $z\gtrsim5$. We show that these line profiles are particularly sensitive to the impact of resonant scattering from infalling IGM and can be strongly attenuated even when the IGM is highly ionized at $z\simeq 5$. We compare these expectations against a new database of $z\gtrsim6.5$ galaxies with robust velocity profiles measured with JWST/NIRSpec.

[43] arXiv:2404.18733 (replaced) [pdf, html, other]

Title: Dynamical friction in the quasi-linear formulation of MOND

Pierfrancesco Di Cintio, Federico Re, Caterina Chiari

Comments: 12 pages, 3 Figures. Version accepted for publication in A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)

Aims. We explore the dynamical friction on a test mass in gravitational systems in the Quasi linear formulation of Modified Newtonian Dynamics (QuMOND). Methods. Exploiting the quasi linearity of QuMOND we derive a simple expression for the dynamical friction in akin to its Newtonian counterpart in the standard Chandrasekhar derivation. Moreover, adopting a mean field approach based on the Liouville equation we obtain a more rigorous (though in integral form) dynamical friction formula that can be evaluated numerically for a given choice of the QuMOND interpolation function. Results. Consistently with previous work, we observe that dynamical friction is stronger in MOND with respect to a baryon only Newtonian system with the same mass distribution. This amounts to a correction of the Coulomb logarithmic factor via extra terms proportional to the MOND radius of the system. Moreover, with the aid of simple numerical experiments we confirm our theoretical predictions and those of previous work on MOND.

[44] arXiv:2405.06017 (replaced) [pdf, html, other]

Title: Effect of the Large Magellanic Cloud on the kinematics of Milky Way satellites and virial mass estimate

Andrey Kravtsov, Sophia Winney

Comments: 9 pages, 11 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present a study illustrating the effects of the passage of a Large Magellanic Cloud (LMC) mass satellite on the distance and velocity distributions of satellites in $\Lambda+$Cold Dark Matter simulations of Milky Way (MW) sized halos. In agreement with previous studies, we find that during such a passage the velocity distribution develops a high-velocity tail, which can bias velocity-based virial halo mass estimates. When the velocity distribution of MW satellites is corrected for effects of the LMC passage, it is consistent with the distributions in halos of masses as low as $M_{\rm 200c}=8\times 10^{11}\, M_\odot$ and as high as $1.5\times 10^{12}\,M_\odot$. We present a new halo mass estimator $M_{\rm 200c}=c\sigma^2_{\rm 3D}r_{\rm med}$, where $c$ is the coefficient calibrated using satellite systems in the simulated MW-sized halos, $\sigma^2_{\rm 3D}$ is the variance of 3D velocities taken with the sign of the radial velocity of each satellite, and $r_{\rm med}$ is the median halocentric distance of the satellites. We show that the estimator has only $s=8\%$ scatter around the median relation of the estimated and true halo masses and deviates by $<2s$ from the median during the pericentric passage of an LMC-like subhalo. This is because $\sigma^2_{\rm 3D}$ and $r_{\rm med}$ deviate in the opposite directions during such passages. We apply the estimator to the MW satellite system and estimate the virial mass of the Milky Way of $M_{\rm 200c}=9.96\pm 1.45\times 10^{11}\, M_\odot$, in good agreement with several recent estimates using other methods.

[45] arXiv:2405.09609 (replaced) [pdf, html, other]

Title: Open star clusters and their asymmetrical tidal tails

Pavel Kroupa (Bonn, Prague), Jan Pflamm-Altenburg (Bonn), Sergij Mazurenko (Bonn), Wenjie Wu (Bonn), Ingo Thies (Bonn), Vikrant Jadhav (Bonn), Tereza Jerabkova (Garching)

Comments: 22 pages, 14 figures, 1 table, LaTeX, ApJ, in press; replaced version contains minor corrections for consistency with published version

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Stars that evaporate from their star cluster by the energy equipartition process end up either in a leading or a trailing tidal tail. In Newtonian gravitation and for open star clusters in the Solar vicinity, the tidal threshold, or prah, for escape is symmetrical, such that the leading and trailing tails are equally populated. The data by six independent teams that applied the convergent point method to map out the tidal tails of four open clusters (the Hyades, the Praesepe, Coma Berenices and COIN-Gaia13) using Gaia DR2 and DR3 are here applied to test for the expected symmetry. All tidal tails contain more stars in the leading tail. The combined confidence amounts to an 8 sigma falsification of the prah symmetry. The same test using Milgromian dynamics leads to consistency with the data. More effort needs to be exerted on this matter, but the data indicate with high confidence that the tidal prah of an open star cluster is asymmetrical with the corresponding confidence that Newtonian gravitation is falsified. Open star clusters depopulate more rapidly in Milgromian than in Newtonian dynamics and the COIN-Gaia13 cluster is here found to be nearly completely dissolved. In view of these results, the wide-binary star test and the Keplerian Galactic rotation curve finding are briefly discussed.

[46] arXiv:2405.18336 (replaced) [pdf, html, other]

Title: WISE2MBH: A scaling-based algorithm for probing supermassive black hole masses through WISE catalogues

J. Hernández-Yévenes, N. Nagar, V. Arratia, T. H. Jarrett

Comments: 21 pages, 13 main + 4 appendix figures, Figure 11 and its discussion updated, reference updated, published in MNRAS

Journal-ref: Monthly Notices of the Royal Astronomical Society, Volume 531, Issue 4, July 2024, Pages 4503-4523

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Supermassive Black Holes (SMBHs) are commonly found at the centers of massive galaxies. Estimating their masses ($M_\text{BH}$) is crucial for understanding galaxy-SMBH co-evolution. We present WISE2MBH, an efficient algorithm that uses cataloged Wide-field Infrared Survey Explorer (WISE) magnitudes to estimate total stellar mass ($M_*$) and scale this to bulge mass ($M_\text{Bulge}$), and $M_\text{BH}$, estimating the morphological type ($T_\text{Type}$) and bulge fraction ($B/T$) in the process. WISE2MBH uses scaling relations from the literature or developed in this work, providing a streamlined approach to derive these parameters. It also distinguishes QSOs from galaxies and estimates the galaxy $T_\text{Type}$ using WISE colors with a relation trained with galaxies from the 2MASS Redshift Survey. WISE2MBH performs well up to $z\sim0.5$ thanks to K-corrections in magnitudes and colors. WISE2MBH $M_\text{BH}$ estimates agree very well with those of a selected sample of local galaxies with $M_\text{BH}$ measurements or reliable estimates: a Spearman score of $\sim$0.8 and a RMSE of $\sim$0.63 were obtained. When applied to the ETHER sample at $z\leq0.5$, WISE2MBH provides $\sim$1.9 million $M_\text{BH}$ estimates (78.5\% new) and $\sim$100 thousand upper limits. The derived local black hole mass function (BHMF) is in good agreement with existing literature BHMFs. Galaxy demographic projects, including target selection for the Event Horizon Telescope, can benefit from WISE2MBH for up-to-date galaxy parameters and $M_\text{BH}$ estimates. The WISE2MBH algorithm is publicly available on GitHub.

[47] arXiv:2406.08561 (replaced) [pdf, html, other]

Title: Theory and Observation of Winds from Star-Forming Galaxies

Todd A. Thompson, Timothy M. Heckman

Comments: 68 pages, 11 figures, 2 tables. Authors' version. To appear in Annual Reviews of Astronomy and Astrophysics 2024, Vol 62. Comments welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Galactic winds shape the stellar, gas, and metal content of galaxies. To quantify their impact, we must understand their physics. We review potential wind-driving mechanisms and observed wind properties, with a focus on the warm ionized and hot X-ray-emitting gas. Energy and momentum injection by supernovae (SNe), cosmic rays, radiation pressure, and magnetic fields are considered in the light of observations: (1) Emission and absorption line measurements of cool/warm gas provide our best physical diagnostics of galactic outflows. (2) The critical unsolved problem is how to accelerate cool gas to the high velocities observed. Although conclusive evidence for no one mechanism exists, the momentum, energy, and mass-loading budgets observed compare well with theory. (3) A model where star formation provides a force $\sim L/c$, where $L$ is the bolometric luminosity, and cool gas is pushed out of the galaxy's gravitational potential, compares well with available data. The wind power is $\sim0.1$ that provided by SNe. (4) The very hot X-ray emitting phase, may be a (or the) prime mover. Momentum and energy exchange between the hot and cooler phases is critical to the gas dynamics. (5) Gaps in our observational knowledge include the hot gas kinematics and the size and structure of the outflows probed with UV absorption lines. Simulations are needed to more fully understand mixing, cloud-radiation, cloud-cosmic ray, and cloud-hot wind interactions, the collective effects of star clusters, and both distributed and clustered SNe. Observational works should seek secondary correlations in the wind data that provide evidence for specific mechanisms and compare spectroscopy with the column density-velocity results from theory.

[48] arXiv:2406.09453 (replaced) [pdf, html, other]

Title: Bar formation and evolution in the cosmological context: Inputs from the Auriga simulations

Francesca Fragkoudi, Robert Grand, Rüdiger Pakmor, Facundo Gómez, Federico Marinacci, Volker Springel

Comments: 21 pages including Appendices, 17 figures, submitted to MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Galactic bars drive the internal evolution of spiral galaxies, while their formation is tightly coupled to the properties of their host galaxy and dark matter halo. To explore what drives bar formation in the cosmological context and how these structures evolve throughout cosmic history, we use the Auriga suite of magneto-hydrodynamical cosmological zoom-in simulations. We find that bars are robust and long-lived structures, and we recover a decreasing bar fraction with increasing redshift which plateaus around $\sim20\%$ at $z\sim3$. We find that bars which form at low and intermediate redshifts grow longer with time, while bars that form at high redshifts are born `saturated' in length, likely due to their merger-induced formation pathway. This leads to a larger bar-to-disc size ratio at high redshifts as compared to the local Universe. We subsequently examine the multi-dimensional parameter space thought to drive bar formation. We find that barred galaxies tend to have lower Toomre $Q$ values at the time of their formation, while we do not find a difference in the gas fraction of barred and unbarred populations when controlling for stellar mass. Barred galaxies tend to be more baryon-dominated at all redshifts, assembling their stellar mass earlier, while galaxies that are baryon-dominated but that do not host a bar, have a higher ex-situ bulge fraction. We explore the implications of the baryon-dominance of barred galaxies on the Tully-Fisher relation, finding an offset from the unbarred relation; confirming this in observations would serve as additional evidence for dark matter, as this behaviour is not readily explained in modified gravity scenarios.

[49] arXiv:2406.10877 (replaced) [pdf, html, other]

Title: WALLABY Pilot Survey: the Tully-Fisher relation in the NGC 4808, Vela and NGC 5044 fields

Jeremy Mould, T. H. Jarrett, Hélène Courtois, Albert Bosma, Nathan Deg, Alexandra Dupuy, Lister Staveley-Smith, E.N. Taylor, Jayanne English, S. H. A. Rajohnson, Renée Kraan-Korteweg, Duncan Forbes, Helga Dénes, Karen Lee-Waddell, Austin Shen, O. I. Wong, Benne Holwerda, Bärbel Koribalski, Denis Leahy, Pavel Mancera Piña, Niankun Yu

Comments: to appear in MNRAS. One figure removed

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The Tully-Fisher Relation (TFR) is a well-known empirical relationship between the luminosity of a spiral galaxy and its circular velocity, allowing us to estimate redshift independent distances. Here we use high signal-to-noise HI 21-cm integrated spectra from the second pilot data release (PDR2, 180 deg2) of the Widefield ASKAP L-band Legacy All-sky Blind surveY (WALLABY). In order to prepare for the full WALLABY survey, we have investigated the TFR in phase 2 of the pilot survey with a further three fields. The data were obtained with wide-field Phased Array Feeds on the Australian Square Kilometre Array Pathfinder (ASKAP) and have an angular resolution of 30 arcsec and a velocity resolution of ~4 km/s. Galaxy luminosities have been measured from the Wide-field Infrared Survey Explorer (WISE), and optical galaxy inclinations from the Dark Energy Camera Legacy Survey. We present TFRs for wavelengths from 0.8-3.4{\mu}m. We examine sources of galaxy inclination data and investigate magnitudes from the DECam Local Volume Exploration Survey (DELVE) and DENIS catalogues and the 4HS target catalogue based on the VISTA Hemisphere Survey (VHS). We consider the baryonic TFR. These are all of interest for TFR using the full WALLABY survey of 200,000 galaxies. We demonstrate that WALLABY TFR distances can take their place among state of the art studies of the local velocity field.

[50] arXiv:2406.11987 (replaced) [pdf, html, other]

Title: The Nearly Universal Disk Galaxy Rotation Curve

Raj Patel (Queen's), Nikhil Arora (Queen's), Stéphane Courteau (Queen's), Connor Stone (UdeM), Matthew Frosst (ICRAR/UWA), Lawrence Widrow (Queen's)

Comments: 36 full pages, 13 figures, 2 appendices. Accepted for publication in the Astrophysical Journal

Subjects: Astrophysics of Galaxies (astro-ph.GA)

The Universal Rotation Curve (URC) of disk galaxies was originally proposed to predict the shape and amplitude of any rotation curve (RC) based solely on photometric data. Here, the URC is investigated with an extensive set of spatially-resolved rotation curves drawn from the PROBES-I, PROBES-II, and MaNGA data bases with matching multi-band surface brightness profiles from the DESI-LIS and WISE surveys for 3,846 disk galaxies. Common URC formulations fail to achieve an adequate level of accuracy to qualify as truly universal over fully sampled RCs. We develop neural network (NN) equivalents for the proposed URCs which predict RCs with higher accuracy, showing that URC inaccuracies are not due to insufficient data but rather non-optimal formulations or sampling effects. This conclusion remains even if the total RC sample is pruned for symmetry. The latest URC prescriptions and their NN equivalents trained on our sub-sample of 579 disk galaxies with symmetric RCs perform similarly to the URC/NN trained on the complete data sample. We conclude that a URC with an acceptable level of accuracy ($\Delta V_{\rm circ} \lesssim15$ per cent) at all radii would require a detailed modelling of a galaxy's central regions and outskirts (e.g., for baryonic effects leading to contraction or expansion of any dark-matter-only halo).

[51] arXiv:2307.11409 (replaced) [pdf, html, other]

Title: Direct signatures of the formation time of galaxies

Yaniv Donath, Matthew Lewandowski, Leonardo Senatore

Comments: PRD version, extended discussion, 5+3 pages, 1 figure, ancillary file included

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

We show that it is possible to directly measure the formation time of galaxies using large-scale structure. In particular, we show that the large-scale distribution of galaxies is sensitive to whether galaxies form over a narrow period of time before their observed times, or are formed over a time scale on the order of the age of the Universe. Along the way, we derive simple recursion relations for the perturbative terms of the most general bias expansion for the galaxy density, thus fully extending the famous dark-matter recursion relations to generic tracers.

[52] arXiv:2310.06120 (replaced) [pdf, html, other]

Title: XLSSC 122 caught in the act of growing up: Spatially resolved SZ observations of a z=1.98 galaxy cluster

J. van Marrewijk, L. Di Mascolo, A. S. Gill, N. Battaglia, E. S. Battistelli, J. R. Bond, M. J. Devlin, P. Doze, J. Dunkley, K. Knowles, A. Hincks, J. P. Hughes, M. Hilton, K. Moodley, T. Mroczkowski, S. Naess, B. Partridge, G. Popping, C. Sifón, S. T. Staggs, E. J. Wollack

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

How protoclusters evolved from sparse galaxy overdensities to mature galaxy clusters is still not well understood. In this context, detecting and characterizing the hot ICM at high redshifts (z~2) is key to understanding how the continuous accretion from and mergers along the filamentary large-scale structure impact the first phases of cluster formation. We study the dynamical state and morphology of the z=1.98 galaxy cluster XLSSC 122 with high-resolution observations (~5") of the ICM through the SZ effect. Via Bayesian forward modeling, we map the ICM on scales from the virial radius down to the core of the cluster. To constrain such a broad range of spatial scales, we employ a new technique that jointly forward-models parametric descriptions of the pressure distribution to interferometric ACA and ALMA observations and multi-band imaging data from the 6-m, single-dish Atacama Cosmology Telescope. We detect the SZ effect with $11\sigma$ in the ALMA+ACA observations and find a flattened inner pressure profile that is consistent with a non-cool core classification with a significance of $>3\sigma$. In contrast to the previous works, we find better agreement between the SZ effect signal and the X-ray emission as well as the cluster member distribution. Further, XLSSC 122 exhibits an excess of SZ flux in the south of the cluster where no X-ray emission is detected. By reconstructing the interferometric observations and modeling in the uv-plane, we obtain a tentative detection of an infalling group or filamentary-like structure that is believed to boost and heat up the ICM while the density of the gas is low. In addition, we provide an improved SZ mass of $M_{500,\mathrm{c}} = 1.66^{+0.23}_{-0.20} \times 10^{14} \rm M_\odot$. Altogether, the observations indicate that we see XLSSC 122 in a dynamic phase of cluster formation while a large reservoir of gas is already thermalized.

[53] arXiv:2402.16635 (replaced) [pdf, html, other]

Title: Cosmic Type Ia SN rate and constraints on SN Ia progenitors

P.A. Palicio, F. Matteucci, M. Della Valle, E. Spitoni

Comments: Accepted for publication in A&A

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

Type Ia supernovae play a key role in the evolution of galaxies by polluting the interstellar medium with a fraction of iron peak elements larger than that released in the core collapse supernova events. Their light-curve, moreover, is widely used in cosmological studies as it constitutes a reliable distance indicator at extra-galactic scales. Among the mechanisms proposed to explain the Type Ia SNe, the single and double degenerate channels are thought to be the dominant ones, which imply a different distribution of time delays between the progenitor formation and the explosion. In this paper, we aim at determining the dominant mechanism by comparing a compilation of Type Ia SN rates with those computed from various cosmic star formation histories coupled with different delay time distribution functions, and evaluating the relative contributions of both channels. By using a least-squares fitting procedure, we model the observations of Type Ia SN rates assuming different combinations of three recent cosmic star formation rates and seven delay time distributions. The goodness of these fits are statistically quantified by the chi-squared test. For two of the three cosmic star formation rates, the single degenerate scenario provides the most accurate explanation for the observations, while a combination of 34% single degenerate and 66% double degenerate delay time distributions is more plausible for the remaining tested cosmic star formation rates. The wide double degenerate scenario mechanism slightly under-predicts the observations at redshift z>1, unless the cosmic SFR flattens in that regime. On the contrary, although the purely close double degenerate scenario can be ruled out, we cannot rule out a mixed scenario with single and double degenerate progenitors.

[54] arXiv:2404.05786 (replaced) [pdf, html, other]

Title: Repeating partial disruptions and two-body relaxation

Luca Broggi, Nicholas C. Stone, Taeho Ryu, Elisa Bortolas, Massimo Dotti, Matteo Bonetti, Alberto Sesana

Comments: Open Journal of Astrophysics, accepted for publication

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

Two-body relaxation may drive stars onto near-radial orbits around a massive black hole, resulting in a tidal disruption event (TDE). In some circumstances, stars are unlikely to undergo a single terminal disruption, but rather to have a sequence of many grazing encounters with the black hole. It has long been unclear what is the physical outcome of this sequence: each of these encounters can only liberate a small amount of stellar mass, but may significantly alter the orbit of the star. We study the phenomenon of repeating partial tidal disruptions (pTDEs) by building a semi-analytical model that accounts for mass loss and tidal excitation. In the empty loss cone regime, where two-body relaxation is weak, we estimate the number of consecutive partial disruptions that a star can undergo, on average, before being significantly affected by two-body encounters. We find that in this empty loss cone regime, a star will be destroyed in a sequence of weak pTDEs, possibly explaining the tension between the low observed TDE rate and its higher theoretical estimates.

[55] arXiv:2405.01950 (replaced) [pdf, other]

Title: Probabilistic Lagrangian bias estimators and the cumulant bias expansion

Jens Stücker, Marcos Pellejero-Ibáñez, Raul E. Angulo, Francisco Maion, Rodrigo Voivodic

Comments: 26 pages, 16 figures, submitted to A&A

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

The spatial distribution of galaxies is a highly complex phenomenon currently impossible to predict deterministically. However, by using a statistical $\textit{bias}$ relation, it becomes possible to robustly model the average abundance of galaxies as a function of the underlying matter density field. Understanding the properties and parametric description of the bias relation is key to extract cosmological information from future galaxy surveys. Here, we contribute to this topic primarily in two ways: (1) We develop a new set of probabilistic estimators for bias parameters using the moments of the Lagrangian galaxy environment distribution. These estimators include spatial corrections at different orders to measure bias parameters independently of the damping scale. We report robust measurements of a variety of bias parameters for haloes, including the tidal bias and its dependence with spin at a fixed mass. (2) We propose an alternative formulation of the bias expansion in terms of "cumulant bias parameters" that describe the response of the logarithmic galaxy density to large-scale perturbations. We find that cumulant biases of haloes are consistent with zero at orders $n > 2$. This suggests that: (i) previously reported bias relations at order $n > 2$ are an artefact of the entangled basis of the canonical bias expansion; (ii) the convergence of the bias expansion may be improved by phrasing it in terms of cumulants; (iii) the bias function is very well approximated by a Gaussian -- an avenue which we explore in a companion paper.

[56] arXiv:2405.01951 (replaced) [pdf, other]

Title: Gaussian Lagrangian Galaxy Bias

Jens Stücker, Marcos Pellejero-Ibáñez, Rodrigo Voivodic, Raul E. Angulo

Comments: 21 pages, 12 figures, submitted to A&A

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

Understanding $\textit{galaxy bias}$ -- that is the statistical relation between matter and galaxies -- is of key importance for extracting cosmological information from galaxy surveys. While the bias function $f$ -- that is the probability of forming galaxy in a region with a given density field -- is usually approximated through a parametric expansion, we show here, that it can also be measured directly from simulations in a non-parameteric way. Our measurements show that the Lagrangian bias function is very close to a Gaussian for halo selections of any mass. Therefore, we newly introduce a Gaussian bias model with several intriguing properties: (1) It predicts only strictly positive probabilities $f > 0$ (unlike expansion models), (2) It has a simple analytic renormalized form and (3) It behaves gracefully in many scenarios where the classical expansion converges poorly. We show that the Gaussian bias model describes the galaxy environment distribution $p(\delta | \mathrm{g})$, the scale dependent bias function $f$ and the renormalized bias function $F$ of haloes and galaxies generally equally well or significantly better than a second order expansion with the same number of parameters. We suggest that a Gaussian bias approach may enhance the range of validity of bias schemes where the canonical expansion converges poorly and further, that it may make new applications possible, since it guarantees the positivity of predicted galaxy densities.

[57] arXiv:2405.17772 (replaced) [pdf, html, other]

Title: A Contact Binary Mis-Classified as an Ellipsoidal Variable: Complications for Detached Black Hole Searches

Tyrone N. O'Doherty, Arash Bahramian, Adelle J. Goodwin, James C. A. Miller-Jones, Jerome A. Orosz, Jay Strader

Comments: Accepted for publication in AJ. 16 pages, 8 figures, 2 tables. Updated description of ASAS-SN ellipsoidal search in Section 4.4 and author affiliations

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

Identifying sources exhibiting ellipsoidal variability in large photometric surveys is becoming a promising method to search for candidate detached black holes in binaries. This technique aims to exploit the orbital-phase dependent modulation in optical photometry caused by the black hole distorting the shape of the luminous star to constrain the mass ratio of the binary. Without understanding if, or how much, contamination is present in the candidate black hole samples produced by this new technique it is hard to leverage them for black hole discovery. Here, we follow up one of the best candidates identified from Gaia Data Release 3, Gaia DR3 4042390512917208960, with a radial velocity campaign. Combined photometric and radial velocity modelling, along with spectral disentangling, suggests that the true mass ratio (mass of the unseen object divided by the mass of the luminous star) is an order of magnitude smaller than that inferred assuming the modulations arise from ellipsoidal variability. We therefore infer that this system is likely a contact binary, or on the boundary of both stars nearly filling their Roche lobes, however, further observations are required to confidently detect the secondary. We find that the well-known problem of discriminating between ellipsoidal and contact binary light curves results in a larger contamination from contact binaries than previously suggested. Until ellipsoidal variables can be reliably distinguished from contact binaries, samples of black hole candidates selected based on ellipsoidal variability are likely to be highly contaminated by contact binaries or similar systems.