Astrophysics of Galaxies
ACES VII. Compact Continuum Source Catalog of the Central Molecular Zone
Jennifer Wallace, Cara Battersby, Nazar Budaiev et al. (+58 more)
The Central Molecular Zone (CMZ) resides in the inner few hundred parsecs of our
Galaxy, and despite being the largest reservoir of dense molecular gas in the Milky Way, it has a relatively low present-day
star formation rate (SFR) of $\sim0.08~M_{\odot}~\text{yr}^{-1}$. Continuum and spectral line observations from the Atacama Large Millimeter/submillimeter Array (ALMA) CMZ Exploration Survey (ACES) provide the first full-coverage, high-resolution map of the inner 200 parsecs of the CMZ at 3 mm. In this paper we present the ACES catalog of compact continuum sources, the most complete catalog of potential sites of
star formation in the CMZ to date. Using an automated dendrogram-based source extraction procedure in combination with a by-eye morphological classification scheme, we produce a `full' catalog of 1735 detections in total. Additionally, we use spectral index measurements to generate a `filtered' catalog of 567 sources with minimal contamination from non-thermal filaments and extended free-free emission. We find that 359 ($\sim63\%$) of the filtered catalog sources are located at column densities $< 10^{23}$ cm$^{-2}$, outside of the densest molecular cloud regions, 195 of which have not been identified in previous surveys. After cross-referencing with various catalogs generated from data at different wavelengths, we consider it likely that many of these newly discovered detections are produced by pre/protostellar sources or compact HII regions.
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All authors Jennifer Wallace, Cara Battersby, Nazar Budaiev, H Perry Hatchfield, Ashley T. Barnes, Taehwa Yoo, Miriam G. Santa-Maria, Antonio Daley, Q. Daniel Wang, Anika Schmiedeke, Kaitlyn E. Sheriff, Jairo Armijos-Abendaño, Daniel Walker, Gwenllian Williams, Dani R. Lipman, Farideh Mazoochi, Natalie O. Butterfield, Francisco Nogueras-Lara, Yoshiaki Sofue, Ralf S. Klessen, Simon C. O. Glover, Katharina Immer, Savannah R. Gramze, Katarzyna M. Dutkowska, Rojita Buddhacharya, Laura Colzi, Ashley Lieber, Alyssa Bulatek, Michael Wieber, Pablo García, Denise Riquelme-Vásquez, Emad Alkhuja, Yue Hu, Dennis Perlot, Howard A. Smith, Victor M. Rivilla, Wenyu Jiao, Fengwei Xu, Jonathan D. Henshaw, Adam Ginsburg, Elisabeth A. C. Mills, Qizhou Zhang, Steven N. Longmore, Nguyen M. Khang, Galaxy Salo, Jakub Poznanski, Dylan Pare, Maya Petkova, Izaskun Jiménez-Serra, Xing Lu, Sergio Martin, Alvaro Sanchez-Monge, Bijas Najimudeen, Christoph Federrath, Tabassum S. Tanvir, Pei-Ying Hsieh, John Bally, Paul Ho, Mattia C. Sormani, Robin G. Tress, Jaime E. Pineda
Astrophysics of Galaxies · Cross-listed from astro-ph.SR
Modeling Rotation in the Old, Cold Domain: Implications on Gyrochronology and the Stellar Magnetic Wind
Amanda L. Ash, Yuxi Lu and Marc H. Pinsonneault
Gyrochronology ties stellar rotation periods to ages. It is well studied in the young, open cluster age domain, but there are few constraints on gyrochronology in the old field
star regime. In this work we use gyro-kinematic ages to explore the
spin down of
stars in this formerly inaccessible domain. Using forward modeling techniques which relax strict Rossby scaled assumptions, we find evidence for a departure from a standard
spin down models. This departure can be explained with a mass-dependent term either in the global strength of the stellar wind or in the relationship between angular velocity and wind strength. Models with this additional mass- dependence help explain prior difficulty in fitting open cluster rotation distributions across the full mass range. Additionally, we use rotation models to identify an mass-dependent age domain over which wind driven stellar
spin down can be isolated from other physical effects. For lower mass
stars, this age domain is most affected by the core-envelope coupling timescale, where as higher mass
stars are more subject to inertial effects late in their main sequence lifetimes. Using simple, analytic models of stellar
spin down in this domain is unable to determine whether the stellar wind has a mass-dependence or if the stellar wind is strictly Skumanich-like in nature. In future studies of rotational and dynamo
evolution we advocate for a forward modeling approach to gyrochronology over purely empirical approaches due to its superior ability to trace physical effects governing stellar
spin down.
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Astrophysics of Galaxies
Early Supermassive Black Holes and Little Red Dots Require Free-Fall Growth
Junehyoung Jeon, Volker Bromm, Michael Boylan-Kolchin et al. (+1 more)
Supermassive black holes/active galactic
nuclei (SMBHs/AGN), forming only a few hundred million years after the Big Bang as observed with the James Webb Space
Telescope (JWST), challenge theoretical understanding. How could they grow so massive $(M_{\rm BH} > 10^6 {\rm \,M}_\odot)$ so quickly after initial seeding? Is this rapid growth related to the numerous and enigmatic Little Red Dots (LRDs), compact sources with AGN-like characteristics, discovered by JWST? To address these mysteries, we consider the first-order constraint on SMBH growth: enough baryonic material has to reach the vicinity of the SMBH seed, located near the bottom of the gravitational potential well of the host dark matter
halo. We specifically examine cold-mode
accretion, where gas from the
cosmic environment flows into the virialized
halo in cold streams without being shock-heated, efficiently reaching the center on a free-fall timescale. We find that cold mode
accretion is necessary to supply material for the SMBHs to reach the observed masses, whereas for shock-heated gas inflow the required amount could only be supplied by implausibly rare
halos. Moreover, cold-mode inflow in rare $(\sim1$ Gpc$^{-3}$)
halos matches the mass and number of the massive
quasars, and
halos able to support super-Eddington
accretion for massive SMBHs ($\sim10^7$ M$_\odot$) match LRD number densities. The decreasing LRD abundance at lower
redshifts may then reflect the termination of cold-mode
accretion in the growing host
halos. The populations of massive SMBHs and LRDs at early times may thus arise naturally from cosmological structure formation, based on the abundance of
halos capable of supplying sufficient material through cold
accretion.
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All authors Junehyoung Jeon, Volker Bromm, Michael Boylan-Kolchin, Julian B. Muñoz
Astrophysics of Galaxies
Reconciling Galactic rotation curve constraints with stellar stream modeling
Mingyu Chang, Francois Hammer and Yanbin Yang
Recent Gaia-based measurements of the Milky Way rotation curve and stellar-stream modeling give significantly different estimates of the Galactic dynamical mass beyond Galactocentric radii of 15 kpc. The stream-based model predicts an outer
halo five times more massive than that predicted by the Gaia rotation curve. We aim to test the impact of analytic assumptions used in stream modeling and to assess whether the currently available stream constraints can distinguish between low- and high-mass Galactic potentials. We first compared globular-cluster disruption in analytic and N-body Milky Way potentials. We then modeled Palomar~5 and ATLAS–Aliqa Uma, which are unique in probing the outer region beyond $R_{GC}$=15 kpc and are the most relevant to understanding the mass discrepancy. Both streams have usable constraints on sky position, proper motion, line-of-sight velocity, and RR~Lyrae distance. They were modeled for both a rotation-curve-based and a stream-based Galactic potential. In the N-body simulations, tidal shocks have a stronger effect on the closer orbit than on the more distant orbit, and therefore do not naturally explain the outer-
Galaxy mass discrepancy. For the streams Palomar 5 and ATLAS–Aliqa Uma, simulations performed for both low- and high-mass Galactic potentials provide comparably good fits of their morphologies and kinematics. Neither potential provides a uniformly better match to all observables, and their differences are comparable to the present observational and modeling uncertainties. Current stream data do not discriminate between the low- and high-mass Milky Way models over the radial range probed by Palomar~5 and ATLAS–Aliqa Uma. This resolves the apparent tension between the rotation-curve- and stream-based constraints over this radial range.
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Astrophysics of Galaxies
Weighing Little Red Dots with Transient Events
Vinh Tran, Xuejian Shen, Oliver Zier et al. (+3 more)
Recent JWST observations have revealed a large population of compact red sources at $z \gtrsim 4$, known as Little Red Dots (LRDs), many of which show signatures of accreting massive black holes (BHs). The physical nature of these sources and their connection to host
galaxies are under debate. We propose an independent avenue for constraining their nature through transient phenomena, such as tidal disruption events (TDEs) and quasi-periodic eruptions (QPEs), arising from interactions between a
star and the gas envelope surrounding the BH. These event rates depend sensitively on BH mass and provide a way to "weigh" LRDs. We calculate the expected TDE and QPE rates in LRDs under three distinct scenarios: (1) LRDs are truly overmassive BHs, (2) LRDs have BH masses following the classical local scaling relations (and the reported BH masses in observations are overestimated), and (3) the currently observed LRDs are only the tip of the iceberg of a larger population of low-mass BHs. We find that the predicted TDE and QPE rates differ dramatically across scenarios, especially in the presence of steep stellar cusps. The expected TDE rates per degree-square, assuming a Hernquist stellar distribution with a Bahcall-Wolf cusp embedded, are $2.78 \times 10^{-3}$, $1.96 \times 10^{-3}$, and $3.37 \times 10^{-2} \, {\rm yr}^{-1} \, {\rm deg}^{-2}$ for the three scenarios, respectively, while the QPE rates are $1.64 \times 10^{-2}$, $4.72 \times 10^{-2}$, and $4.96 \times 10^{-1} \, {\rm yr}^{-1} \, {\rm deg}^{-2}$. Upcoming wide-field surveys with Euclid, Roman, and LSST may be capable of detecting these high-
redshift transient events and obtaining light curves, which encode additional information about the BH mass and the gas structure of LRDs. Stellar transient events will provide valuable insight into the early assembly of massive BHs.
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All authors Vinh Tran, Xuejian Shen, Oliver Zier, Anna de Graaff, Rohan P. Naidu, Mark Vogelsberger
Astrophysics of Galaxies
Skyfire: A Spectroscopic Census of Little Red Dots and Broad-Line AGN in the CEERS Field
Dale D. Kocevski, Anthony J. Taylor, Masafusa Onoue et al. (+24 more)
We present the Skyfire program, a 21-hour Cycle 3 JWST/NIRSpec survey with the G395M medium-resolution grating covering five pointings in the Extended Groth Strip. The survey is designed to carry out a systematic census of faint, broad-line AGN candidates with a range of rest-optical colors identified at z > 3 by the
Cosmic Evolution Early Release Science (CEERS) Survey. Our primary targets include photometrically-selected Little Red Dots (LRDs), blue extreme emission line
galaxies (EELGs), and X-ray-detected AGN. We present spectroscopic
redshifts for 178 sources observed by Skyfire, as well as a catalog of 34 sources with broad emission lines in the
redshift range 2.7 < z < 6.5. Our broad-line sample includes 18 LRDs, which brings the spectroscopic completeness of LRDs with $\beta_{\rm opt}>-0.02$ in the CEERS field to 73%. We explore the prevalence of broad emission lines in photometrically-selected LRDs as a function of their rest-frame continuum slope and observed color distributions. We find the broad-line detection fraction in LRDs remains high at relatively blue rest-optical colors and extends smoothly into the bluer regime occupied by Little Blue Dots (LBDs). We discuss the implications of this finding for LRD-LBD unification scenarios. We also find that only 18% (3/17) of EELGs selected primarily for their high-equivalent-width emission lines and compact morphologies exhibit broad emission lines, suggesting these criteria alone are poor predictors of broad-line activity. We present a revised set of LRD selection criteria that captures bluer sources by extending down to $\beta_{\rm opt}=-0.52$. Using this new threshold, we find that $80.9^{+4.6}_{-7.5}\%$ of photometrically-selected LRDs brighter than 26.5 in F444W show broad emission lines and that LRDs make up 54% of the overall broad-line population identified in the CEERS field.
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All authors Dale D. Kocevski, Anthony J. Taylor, Masafusa Onoue, Kohei Inayoshi, Steven L. Finkelstein, Guillermo Barro, Jingsong Guo, Pablo Arrabal Haro, Jonathan R. Trump, Rebecca L. Larson, Mark Dickinson, Casey Papovich, Fabio Pacucci, Pablo G. Perez-Gonzalez, Michaela Hirschmann, Elizabeth J. McGrath, Brenda L. Jones, Nikko J. Cleri, Kelcey Davis, Mauro Giavalisco, Norman A. Grogin, Taylor A. Hutchison, Jeyhan S. Kartaltepe, Allison Kirkpatrick, Gene C. K. Leung, Rachel S. Somerville, Stephen M. Wilkins
Astrophysics of Galaxies
The impact of hot mode accretion and angular momentum conservation on metallicity gradients of galactic discs
Jennifer K.S. Friske, Filippo Fraternali and Gabriele Pezzulli
The hot circumgalactic medium (CGM) of a
galaxy inevitably rotates more slowly than the cold gas in the disc it surrounds, due to a higher pressure support against
gravity. If it accretes vertically onto the disc, angular momentum conservation leads to radial flows, advection of metals inwards and the steepening of a
metallicity gradient. The observed gradient hence carries information on the kinematics of the accreting gas. Previous models built on this premise parametrised the angular momentum mismatch as a simple function of radius, constant in time, rather than derived from the properties of the CGM itself. Here, we present a semi-analytic chemical
evolution model of a
galaxy with a cosmologically motivated
evolution, a self-consistent and time-evolving potential and an isothermal rotating CGM. The model includes inside-out formation and the radial flows induced both by the deepening of the potential well (acting on gas and
stars) and by
accretion, following their combined effect on the gas-phase
metallicity gradient over
cosmic time. We use a
Bayesian framework to fit simultaneously the structural properties and
metallicity gradient of a
galaxy, inferring both the required inside-out growth and the CGM temperature needed to drive the required radial flows and abundance gradient. Fitting our model to the Milky Way, we find a mild preference for a subvirial corona ($T_\mathrm{CGM}/T_{200}=0.82^{+0.44}_{-0.38}$), in mild tension with observations, and we discuss possible resolutions. The predicted CGM rotation velocity lies between ~100-160 km/s at the present time and is substantially lower at earlier epochs. We further recover an
evolution of the gradient over the past ~8Gyr consistent with observations. Our approach is not restricted to the Milky Way and can be directly applied to external
galaxies, offering a new handle to constrain hot mode
accretion onto galactic discs.
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Astrophysics of Galaxies
ALMA CO(2-1) Gas Dynamics in NGC 315: A Multi-Method Benchmark for Supermassive Black Hole Mass Measurement
Dieu D. Nguyen, Benjamin D. Boizelle, Hai N. Ngo et al. (+11 more)
We present ALMA Cycle~7 \cotwo\ observations of the circumnuclear disk in NGC~315 at an angular resolution of $0\farcs230\times0\farcs175$, improving on past measurements and resolving the sphere of influence (SOI) of the supermassive black hole (SMBH), whose mass has previously been estimated of $M_{\rm BH}= \left(2.08^{+0.33}_{-0.15}\right) \times 10^9$~M$_\odot$ The high spatial resolution and sensitivity enable robust full-cube forward modeling of the molecular gas kinematics and a direct comparison of multiple independent gas-based dynamical modeling techniques. We apply standard
Bayesian codes using both MCMC and nested sampling approaches, as well as a frequentist code to the same
dataset, exploring systematic uncertainties associated with the stellar mass distribution, gas surface-brightness parameterization, and disk geometry. All methods yield consistent black hole masses, indicating that the inferred $M_{\rm BH}$ is not strongly method-dependent. Combining the ensemble of independent molecular-gas-based models, we derive an ensemble median black hole mass of $M_{\rm BH}/10^9\,\mathrm{M_\odot} = 2.02^{+0.04}_{-0.05}$(stat)$^{+0.05}_{-0.04}$(sys), where the comparable contributions to the full error budget arise from modeling systematics rather than formal fitting uncertainties. Our $M_{\rm BH}$ is consistent with the empirical $M_{\rm BH}$–$\sigma_\star$ and $M_{\rm BH}$–$L_{\rm bulge}$ scaling relations, and lies 32% below an independent stellar-dynamical measurement, a discrepancy we discuss in the context of systematic differences between gas- and stellar-based methods. NGC~315 serves as a
benchmark for quantifying molecular gas-dynamical $M_{\rm BH}$ systematic uncertainties and for future cross-comparisons of gaseous and stellar dynamical approaches.
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All authors Dieu D. Nguyen, Benjamin D. Boizelle, Hai N. Ngo, Elena Gallo, Tuan N. Le, Sabine Thater, Tien H. T. Ho, Tinh Q. T. Le, Que T. Le, Sam Norcross, Xueyi Li, Huy G. Tong, Nghi K. N. Le, Huy M. B. Tran
Astrophysics of Galaxies · Cross-listed from astro-ph.SR
From spectroscopic abundances to evolutionary [$\alpha$/Fe] in stellar models
Pedro Diaz Reeve and Aldo Serenelli
Large-scale, high-resolution spectroscopic surveys map detailed chemical abundance patterns for millions of
stars. However, libraries of stellar
evolution models and isochrones still rely on a simplified description of chemical abundances, generally assuming either solar-scaled compositions or a constant enrichment for all $\alpha$-elements. Moreover, the definition of $\alpha$-enrichment is survey-dependent and is not necessarily the most relevant quantity for stellar structure and
evolution. In the era of precision stellar astrophysics, stellar models need to better account for the wealth of chemical information provided by spectroscopic surveys. We develop a perturbative method to compute stellar
evolution tracks for
stars with arbitrary patterns of $\alpha$-elements. We quantify the response of stellar evolutionary tracks to variations of individual $\alpha$-elements through
polynomial expansions, which can be linearly combined to produce synthetic tracks for a given abundance pattern. We also introduce the evolutionary $\alpha$-enhancement, [$\alpha$/Fe]$_{\rm ev}$, a constant enhancement for all $\alpha$-elements that reproduces the impact of an observed abundance pattern on stellar models. We validate both methods using
stars with detailed APOGEE abundances and quantify the differences between spectroscopic [$\alpha$/Fe] and [$\alpha$/Fe]$_{\rm ev}$ for different surveys. We identify a minimal set of chemical elements required for accurate stellar models and present ALCHEMY, a simple and fast tool to compute [$\alpha$/Fe]$_{\rm ev}$ for general $\alpha$-element abundance patterns.
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Astrophysics of Galaxies
Stellar streams around dwarf galaxies are observationally rare in the local Universe
Joanna D. Sakowska, David Martí{\i}nez-Delgado, Sarah Pearson et al. (+6 more)
The frequency and properties of stellar streams around dwarf
galaxies remain observationally under-explored. Building a statistically significant sample is challenging because dwarf
galaxies are smaller, fainter, and far more numerous than massive
galaxies. We present the first results from a systematic survey for stellar streams around dwarf
galaxies. We first introduce a classification metric for satellite
accretion features (streams, shells, and asymmetric stellar
haloes) using DECam imaging from the DES and DECaLS surveys. Applying this metric to the DES footprint, we find a low observed frequency of
accretion features (5.1$\%$) and no bona fide stellar streams (with only one identified in DECaLS). We consider whether the apparent excess of shells relative to streams can be explained by observational biases. Our results indicate that stellar streams are observationally rare in the local Universe, motivating further theoretical work to determine whether this reflects genuine differences in merger rates across
galaxy mass regimes.
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All authors Joanna D. Sakowska, David Martí{\i}nez-Delgado, Sarah Pearson, Francisco J. Riquel-Castilla, Tjitske K. Starkenburg, Giuseppe Donatiello, Alis Deason, Denis Erkal, Ethan D. Taylor
Astrophysics of Galaxies
Magnetohydrodynamics of charged interstellar dust. Multifluid models and study of the linear modes
Gabriel Verrier, Patrick Hennebelle, Ugo Lebreuilly et al. (+1 more)
Interstellar grains play key roles in
star and
planet formation, including the coupling of the gas to the
magnetic field during the protostellar collapse. These roles depend on the local grain size distribution, which requires a multifluid treatment of charged dust. We aim to understand the fundamental physics of the dynamics of a dust distribution in interaction with the gas and the
magnetic field. In particular, the purpose is to characterize the (de)coupling conditions of these different components. We provide a multifluid model of charged dust which accounts for the inertia of the grains. A chemical network is used to simulate the charge
equilibrium in collapsing protostellar cores. We compute the Alfven modes and the magnetosonic modes to understand the coupling regimes between the gas, the dust fluids, and the
magnetic field. We also analyze and compare to the predictions of existing models, that are the neutral dust multifluid and the standard non-ideal magnetohydrodynamics. The charged multifluid model agrees with non-ideal magnetohydrodynamics on the larger scales of a collapsing dense core and the forming disk, while we successfully extend to new regimes where the inertia of dust grains matters. We found that high charge-to-mass dust grains carry the propagation of magnetohydrodynamical waves in protostellar envelopes. We provide analytical expressions of the speed of these waves depending on the dust distribution. The magnetocompressive perturbations lead to local dust-to-gas ratio variations at au scales. A theoretical understanding of the dynamics of a charged dust distribution is provided in the linear regime. The closed set of magnetohydrodynamics equations can be implemented in numerical codes to explore nonlinear effects during the protostellar collapse such as
turbulence, angular momentum transport and
magnetic dust clumping.
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All authors Gabriel Verrier, Patrick Hennebelle, Ugo Lebreuilly, Valentin Vallucci-Goy
Astrophysics of Galaxies
Constraining Baryonic Feedback at $z\sim 1$ with the H$\alpha$ Luminosity Function
Ivan Rapoport, Vincent Desjacques, Ehud Behar et al. (+1 more)
Baryonic feedback remains one of the primary uncertainties in
galaxy formation models because of its impact on the interstellar medium (ISM) and
star formation. We investigate its effect on the H$\alpha$ luminosity function (LF) using the Illustris and IllustrisTNG simulations, incorporating direction-dependent dust attenuation and a physically motivated treatment of the propagation of Lyman-series
photons. We model three sources of H$\alpha$ emission:
star-forming H II regions, collisional excitation and recombination in the diffuse ISM, and AGN-induced photo-excitation of diffuse gas. The models are calibrated against observed H$\alpha$ LFs at $z\sim 1-1.5$ using a single free parameter relating the
star formation rate to the H II-region H$\alpha$ luminosity. We find that emission from diffuse gas contributes $\sim 1\%-10\%$ of the total H$\alpha$ luminosity in both simulation sets. AGN photo-excitation produces only a modest enhancement of the bright end of the LF, although it dominates the H$\alpha$ emission of Illustris
galaxies with $L_{\text{H}\alpha}\gtrsim 3\times10^{42}\ \rm{erg \ s^{-1}}$. The low-feedback IllustrisTNG simulations provide good agreement with the observed LFs for all emission models considered, whereas the high-feedback Illustris simulation fails to simultaneously reproduce the faint and bright ends of the LF at $z\sim 1$. This tension between H$\alpha$ LFs and stacked kSZ measurements highlights the combined power of these probes for constraining the interplay between baryonic feedback, gas properties, and the physics governing emission-line
galaxies.
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All authors Ivan Rapoport, Vincent Desjacques, Ehud Behar, Shmuel Bialy
Astrophysics of Galaxies · Cross-listed from astro-ph.HE
TeV Gamma Rays and Neutrinos from Winds Driven by Radiatively Inefficient Accretion Flows of Low-Luminosity Active Galactic Nuclei
Nobuyuki Sakai, John F. Beacom and Kohta Murase
Recently, the Large High Altitude Air Shower Observatory (LHAASO) reported the first TeV gamma-ray detection from a low-luminosity active galactic
nucleus (LLAGN) lacking a strong jet. This source, NGC 4278, is one of the nearest LLAGNs that can be studied in detail as a template for more distant objects. Most previous studies have focused on the month-scale-variable gamma-ray activities, seeking to explain them with weak jets. We focus instead on NGC 4278's quiet-period emission, proposing a different mechanism based on a wind launched from a radiatively inefficient
accretion flow (RIAF). In particular, we model particle acceleration at a wind-driven shock and calculate the resulting multimessenger emission. To match the TeV gamma-ray fluxes reported by LHAASO in the quiet period, our model requires a wind power of $\lesssim2\times10^{43}~\mathrm{erg~s^{-1}}$ with a spectral index of injected
cosmic rays of 2.0. We show that this is achievable through Bondi
accretion of the ionized gas observed on the 100-pc scale, for a shallow
accretion profile. We discuss the testability of our wind-driven shock scenario with multimessenger observations. As another important application, we extend our model to Sgr A*, the nearest LLAGN, and show that its TeV gamma-ray emission is reproduced with reasonable parameters. Our results suggest that RIAF-driven winds may be a generic emission mechanism in LLAGNs, making this class a potentially important population of both gamma-ray emitters and
cosmic-ray accelerators.
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Astrophysics of Galaxies · Cross-listed from astro-ph.SR
Interferometric Survey of Stellar Parameters: Towards homogeneous FGK stars parameters and surface-brightness color relation in the context of PLATO space mission
Romina V. Ibañez Bustos, Denis Mourard, Nicolas Nardetto et al. (+20 more)
The estimation of stellar angular diameters can be performed from the surface brightness - color relation (SBCR) and photometry. The SBCR have been considered by the PLATO space mission as an independent empirical alternative for estimating stellar radii of FGK
stars. In this context, we have implemented an homogeneous approach not only for calibrating the SBCR for FGK-IV/V
stars but, also for determining their fundamental parameters in order to place the
stars reliably on the HR diagram and to study their impact on the SBCR. We have performed interferometric observations of 18 quiescent FGK-IV/V
stars in the Gaia color range of $3.088 \leq G \leq 5.498$. For the first time, we used 3 different interferometers operating in the $R$, $H$ , and $K$ bands to measure polychromatic limb-darkened angular diameters (LDAD). In parallel, by using public domain spectra we have estimated the stellar parameters ($T_{eff}$, $log g$ and Z) by using the open python tool iSpec. We achieved an average accuracy of 2.3% for the LDAD based on polychromatic observations. However, we have observed that our SBCR does not follow the calibration of the relation between surface brightness and color in Gaia found in the literature. Furthermore, we found that $log g$ and $Z$ have no impact on the SBC relation; given the characteristics of our sample of quiescent
stars, it constitutes an ideal set of targets for conducting a new SBCR calibration within the framework of the PLATO space mission. In this context, we reported a SBCR calibration with $\sigma_{RMS} = $ 0.012, 0.009, 0.009 in the $G, G_{BP}$ and $G_{RP}$ Gaia bands, respectively. This article is part of a series of papers reporting the first results obtained using a polychromatic approach to measure LDAD, employing a fully homogeneous methodology for both determining the fundamental parameters of
stars and measuring the LDAD, $\theta_{LD}$.
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All authors Romina V. Ibañez Bustos, Denis Mourard, Nicolas Nardetto, Jeremy Jones, Nayeem Ebrahimkutty, Juraj Jonák, Hugo Nowacki, Mathieu Vrard, Philippe Berio, Julien Dejonghe, Roxanne Ligi, Frédéric Morand, David Salabert, Orlagh Creevey, Armando Domiciano de Souza, Manon Bailleul, Karine Perraut, Markus Wittkowski, John D. Monnier, Stefan Kraus, Narsireddy Anugu, Mayra Gutierrez, Noura Ibrahim
Astrophysics of Galaxies
Photometric redshifts for active galactic nuclei with LePHARE for the Vera C. Rubin Observatory
R. Shirley, M. Salvato, J. Cohen-Tanugi et al. (+31 more)
Active Galactic
Nuclei (AGN) play a crucial role in
galaxy evolution, but they are a minority of extragalactic sources with diverse Spectral Energy Distributions (SEDs), which depend on their means of selection. Upcoming large-scale surveys such as LSST will identify many AGN, but analysis tools are not optimized for them. The limited number of photometric bands in these surveys impacts the calculation of photometric
redshifts for AGN, which are essential for scientific advancement. We use LePHARE to demonstrate the impact that a limited number of bands and erroneous assumptions have on the determination of the photometric
redshifts of AGN. We conduct tests on six AGN samples selected using X-ray,
radio, infrared, variability, color, and spectroscopic criteria in the COSMOS field, using photometry from HSC-CLAUDS, which is closest in depth and wavelength coverage to LSST. We present the LSST pipeline for LePHARE within the
Redshift Assessment Infrastructure Layers (RAIL), facilitating comparison between SED fitting and machine learning
algorithms. AGN that appear as point-like sources in optical data will be assigned highly unreliable photometric
redshifts if they are processed using
galaxy templates. Additionally, shallow all-sky surveys (like eROSITA, WISE, and ZTF) miss many AGN. As a result, these "hidden" AGN are often misidentified as
galaxies in public survey data, leading to incorrect photometric
redshift. We provide the configurations that are suggested for each type of AGN alongside measures of expected performance as a function of
redshift, magnitude, and selection. To facilitate studies with a panchromatic view of AGN, we also release photometric
redshifts and posterior distributions for all AGN sources identified in the COSMOS field using the six criteria, based on 28-band photometry.
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All authors R. Shirley, M. Salvato, J. Cohen-Tanugi, O. Ilbert, S. Arnouts, R. Ansari, R. Assef, M. Banerji, A. Bongiorno, W. N. Brandt, J. Buchner, J. Comparat, D. Ilić, A. Kovačević, J. Kubica, B. Laloux, O. Lynn, A. Malz, L. Marchetti, C. Mazzucchelli, T. Mkrtchyan, K. Nandra, D. Oldag, C. Ricci, W. Roster, E. Saremi, S. Satheesh-Sheeba, T. Tasnim. Ananna, M. J. Temple, M. Vaccari, A. Viitanen, C. Wolf, Z. Yu, T. Zhang
Astrophysics of Galaxies · Cross-listed from astro-ph.HE
ALMA Observations of DEM L241/LMC P3 in the Large Magellanic Cloud: Evidence for the Formation of Cool Molecular Jets Driven by a Microquasar
Yasuo Fukui, Bhuvana G. R., Hidetoshi Sano et al. (+17 more)
We present ALMA observations of DEML 241/LMC P3, the most luminous $\gamma$-ray binary consisting of a compact object and an O
star, in CO emission. We have found an one-sided jet-like CO feature of 8 pc length and 1 pc width, which accompanies another weaker CO jet candidate with slightly different orientation. The one-sided CO jet exhibits striking
alignment with LMC P3, suggesting that the jet was driven by LMC P3. We have determined kinetic temperature of the CO jet to be significantly high at 33$-$60 K as compared with $\sim$15 K in the nearby non-jet CO cloud whereas no radiative heat source is found. We interpret that the high temperatures are due to shock heating of a microquasar jet driven by the $\gamma$-ray binary, where the compact object has an
accretion disk fed by the O
star winds. The CO jet matches existing predictions from magneto-hydrodynamical simulations, which show that CO jet can form from the interaction of the microquasar jet and an ambient ISM cloud. These results provide strong evidence that CO jets are a signature sculptured by microquasar jets, lending support for mass
accretion in LMC P3 as the $\gamma$-ray origin. The results suggest a second case of CO jets potentially driven by a microquasar along with the CO jets in the microquasar candidate HESS J1023-575 recently identified in the Milky Way. Further, our results suggest the use of sub-mm observations for identifying microquasars, opening a new possible window for their discovery and study.
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All authors Yasuo Fukui, Bhuvana G. R., Hidetoshi Sano, Kisetsu Tsuge, Rami Z. E. Alsaberi, Rin Yamada, Yuya Asano, Aya Bamba, Miroslav Filipovic, Charles Law, Norikazu Mizuno, Toshikazu Onishi, Paul Plucinsky, Gavin Rowell, Manami Sasaki, Piyush Sharda, Hiromasa Suzuki, Kengo Tachihara, Kazuki Tokuda, Yumiko Yamane
Astrophysics of Galaxies · Cross-listed from astro-ph.SR
Phosphorus abundances and multi-element co-enrichment in nearby FGK stars
Dario Esposito, Giovanni Covone, Donato Giovannelli et al. (+9 more)
The distribution of bio-essential elements is key to assessing the chemical fertility of galactic environments. We analyse phosphorus abundances for 233 nearby FGK
stars from the Hypatia Catalog, separating thin- and thick-disk populations. We study [P/Fe] as a function of [Fe/H] and other elemental abundances using non-parametric tests and bootstrap resampling, and we examine residual correlations at fixed [Fe/H] together with molar ratios involving P. We find a [P/Fe]-[Fe/H] trend broadly similar to that of alpha elements, supporting a dominant origin in core-collapse
supernovae, while deviations point to additional nucleosynthetic channels. Phosphorus shows strong positive correlations with several CHNOPS, alpha, and Fe-peak elements, especially in the thin disk. These co-enrichment patterns remain significant at fixed [Fe/H], indicating that they are not a trivial consequence of global
metallicity. Thin-disk
stars are also more enriched than thick-disk
stars in many elements. The solar P/Mg and P/Si ratios are representative of the local stellar population, whereas solar P/O is relatively elevated. Overall, phosphorus emerges as a tracer of genuine multi-element co-enrichment and of the chemical fertility of the solar neighbourhood.
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All authors Dario Esposito, Giovanni Covone, Donato Giovannelli, Paola Manini, Christian Magliano, Laura Inno, Luca Cacciapuoti, Víctor M. Rivilla, Vito Saggese, Leonardo Testi, Emanuele Cristiano, Luca Tonietti
Astrophysics of Galaxies
Broad-band host measurements of little red dots and similar compact nuclei require source-conditioned polychromatic PSFs
Sergio Bonaque-González
Characterizing compact sources in the early Universe is difficult because light from physically distinct components can overlap within the same diffraction-limited image. A common method uses field
stars to model how a single point of light appears and from this estimates the intrinsic structure and contributions of the physical components of the distant object under study. Many important properties inferred for high-
redshift objects depend on the accuracy of this method. Using the little red dots (LRDs) analysed by Zhang et al. as a test case, this work shows that applying the method through broad filters to objects whose spectra differ from those of the field
stars can systematically misassign light, overestimating an existing extended component or creating an apparent one where none exists. At the measured level, this error is large enough to alter the inferred sizes, luminosities and masses, and therefore the physical interpretation of these systems. The physical and mathematical origin of the error is established and a correction applicable to other compact distant sources is demonstrated.
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Astrophysics of Galaxies · Cross-listed from astro-ph.EP
Planar Three-Body Problem: theoretical predictions and simulation results
Yogesh Dandekar, Ethan Springer, Shoval Zard et al. (+3 more)
We investigate the statistical properties of the non-hierarchical planar three-body problem, relevant to astrophysical systems with nearly planar dynamics, including protoplanetary disks and AGN disks. Using the Flux-based statistical theory of the three-body problem, previously studied in three dimensions, we derive theoretical predictions for several statistical observables in the planar case. Focusing on ergodic disintegration outcomes, we compare these predictions directly with numerical simulations and contrast the results with the corresponding unconstrained three-dimensional case. Our analysis is based on one million simulations for each of eight distinct mass sets. We examine escape probabilities, properties of marginal escape events, eccentricity distributions, lifetime distributions, and relative prevalence of prograde and retrograde escapes. While several of the theoretical predictions are in good agreement with the simulations, others exhibit unexpected discrepancies. We discuss possible explanations for these deviations.
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All authors Yogesh Dandekar, Ethan Springer, Shoval Zard, Alessandro Alberto Trani, Barak Kol, Ofek Birnholtz
Astrophysics of Galaxies · Cross-listed from astro-ph.HE
Hunting the nature of the Seyfert 1 galaxy GRS 1734-292: can it be a gamma-ray emitter?
Luigi Foschini
It has been proposed that the
radio-weak Seyfert
galaxy GRS 1734-292 is the counterpart of 3EG J1736-2908 and of the nearby Fermi/LAT source. I examine this identification, considering that the
radio weakness could result from free-free absorption of a relativistic jet. An association with the EGRET detections is plausible, whereas the latest Fermi/LAT localization no longer favors GRS 1734-292. New observations, especially at
radio frequencies of tens of GHz, would help to settle the issue.
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Astrophysics of Galaxies
Testing SALT Approximations with Numerical Radiative Transfer Code. II. Thermal and Microturbulent Line Broadening
Cody Carr, Renyue Cen, Leo Michel-Dansac et al. (+2 more)
Forward models that connect galactic winds to their predicted spectral-line profiles have proved effective for inferring wind properties in controlled settings, but important limitations remain. In particular, many models rely on the Sobolev approximation to solve the radiative transfer equation and neglect line broadening caused by thermal and turbulent motions within the wind. In the first paper of this series, we demonstrated that neglecting this broadening in Semi-Analytical Line Transfer (SALT) models can bias the recovery of fundamental wind properties from mock observations. Here, we extend the SALT framework to incorporate this motion by solving the radiative transfer equation in the single-scattering limit. We treat re-emission using an escape-probability approach similar to that adopted under the Sobolev approximation, while allowing
photons to escape from resonance regions of finite thickness. We validate the model and investigate parameter degeneracies by fitting mock spectra generated with Monte Carlo radiative transfer simulations assuming identical outflow configurations. We identify a degeneracy between the Doppler-broadening parameter and the radial density and velocity profiles: shallower density and velocity gradients can mimic the effects of greater velocity dispersion. Nevertheless, integrated quantities are well recovered. Over the range $13 \leq \log(N_{\mathrm{Si}^+}/\mathrm{cm}^{-2}) \leq 18$, the recovered ionic column densities have a scatter of 0.26 dex and are systematically overestimated by 0.22 dex. Mass-outflow rates evaluated at the terminal wind radius have a scatter of 0.88 dex and are systematically overestimated by 0.51 dex. These results represent substantial improvements over previous versions of the model.
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All authors Cody Carr, Renyue Cen, Leo Michel-Dansac, Claudia Scarlata, Alaina Henry
Astrophysics of Galaxies · Cross-listed from astro-ph.SR
OB stars identified in LAMOST Data Release 10
Guang Yang, Zhicun Liu, Xiao-Long Wang et al. (+2 more)
A large sample of OB
stars plays an important role in studying the stellar parameters of massive
stars, as well as the formation and
evolution of the Milky Way. With the help of the Large Sky Area Multi-Object Fiber Spectroscopic
Telescope (LAMOST) Data Release 10 (DR10), we are able to construct a large sample of OB
stars with spectroscopic data. In this study, we identify 48,463 spectra of 34,550 OB
stars from LAMOST DR10, based on the Hertzsprung-Russell (H-R) diagram constructed with Gaia DR3 data and spectral line indices measured from LAMOST DR10 low-resolution spectra. Among these, 6907 OB
stars are newly identified. We use the MKCLASS tool to derive the spectral subtypes of the OB sample. The spatial distribution of 25,287 OB
stars and the Toomre diagram of 20,397 OB
stars indicate that the majority of these
stars are located in the Galactic disk. Based on their peculiar velocities, we identify 1960 runaway
star candidates.
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All authors Guang Yang, Zhicun Liu, Xiao-Long Wang, Yanjun Guo, Wenyuan Cui
Astrophysics of Galaxies · Cross-listed from astro-ph.EP
Empirical Constraints on the CO Snowline Transition in HD 163296: The Local CO Column and $^{13}$C$^{18}$O Optical Depth
Chunhua Qi, Takahiro Ueda, David J. Wilner et al. (+1 more)
CO isotopologue emission is widely used to infer gas masses and volatile carbon abundances in protoplanetary disks, but converting line emission into a CO column depends on optical depth, temperature structure, linewidth, and isotope ratios. Inferring CO/H$_2$ additionally requires an independent constraint on the local hydrogen column. We use high-resolution $^{13}$C$^{18}$O $2$-$1$ observations of HD 163296 to derive a spatially localized empirical constraint on the CO column at the resolved CO snowline edge. We focus on the 70-75 au annulus, on the inner, high-column side of the observed profile steepening near 75 au. Using RADEX slab calculations conditioned on a two-dimensional temperature structure, we infer an effective beam-averaged CO column from the absolute integrated intensity. Across representative temperatures, isotope-ratio pairs, and effective local linewidths of 0.30 and 0.50 km s$^{-1}$, we find $N_{\rm CO}^{\rm beam}=(1.6-2.4)\times10^{20}$ cm$^{-2}$ and $^{13}$C$^{18}$O line-center optical depths $\tau=0.39-0.97$. Thus, even this rare isotopologue is not safely optically thin at the snowline edge. Adopting $N_{\rm H2}=2.5\times10^{24}$ cm$^{-2}$ from a published parametric gas surface-density profile gives the conditional abundance ${\rm CO/H_2}=(6.4-9.5)\times10^{-5}$. A beam-forward radial-profile analysis gives consistent columns, and a physical disk model with a near-canonical warm-layer CO abundance supplies a comparable CO column. The measurement is consistent with the higher C$^{17}$O-based MAPS estimate. For the adopted hydrogen column, the inferred CO/H$_2$ ratio is consistent with a near-canonical abundance on the warm side of the snowline.
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All authors Chunhua Qi, Takahiro Ueda, David J. Wilner, Catherine C. Espaillat