arXiv subjects

Tyrone E. Woods

Publications and source records attributed to Tyrone E. Woods.

At least 19 recordsLinked to original sources

arXiv2026

The Next Generation Virgo Cluster Survey (NGVS). II. A Catalog of Galaxies in the Virgo Cluster

The Next Generation Virgo Cluster Survey (NGVS) is a deep, high resolution imaging campaign that used the 1 deg$^2$ MegaCam instrument on the Canada-France-Hawaii Telescope to carry out a comprehensive optical survey of the Virgo cluster, from its core to its virial radius. The NGVS covers a contiguous area of 104 deg$^2$ (8.63 Mpc$^2$ at the 16.5 Mpc distance of Virgo) in the $u^*$-,$g$-,$i$-, and $z$-band, with additional limited coverage in $r$. In this paper, we present the final catalog of Virgo galaxies across the entire NGVS area. The catalog includes 3680 galaxies considered to be $bona~fide$ members of the cluster, spanning a factor of 2.5 million in luminosity, from $g = 8.42$ mag to $g = 24.41$ mag ($M_g = -22.67$ mag to $M_g = -6.68$ mag). With 2100 previously uncataloged galaxies, the NGVS catalog augments the number of known Virgo members by a factor 2.3. The catalog is complete down to $g = 18.6$ mag ($M_g=-12.5$ mag, corresponding to a stellar mass $M_* \sim 1.6\times10^7~M_{\odot}$ for an old stellar population) and 50% complete at $g = 22.0$ mag ($M_g=-9.1$ mag, $M_* \sim 6.2\times10^5~M_{\odot}$), three magnitudes deeper than the venerable Virgo Cluster Catalog (VCC), which for over 40 years has served as the reference standard for Virgo. Photometric and structural parameters are derived for all NGVS galaxies and presented in a series of tables, alongside nuclear and morphological classification, as well as stellar masses and, when available, radial velocities.

astro-ph.GA↗

arXiv2026

A new model for the continuum spectra of AM CVn binaries and multi-messenger inference with normalizing flows

Future electromagnetic telescopes, such as $\textit{NewAthena}$, $\textit{CASTOR}$, and an $\textit{AXIS}$-like mission, along with milli-Hz gravitational-wave (GW) detectors such as $\textit{LISA}$, are expected to unearth the population of Galactic ultra-compact binaries (UCBs). Joint multi-messenger detections will probe the uncertain formation, evolution, and observables of mass-transferring UCBs such as AM CVns, but theoretical tools need to be advanced to anticipate future data challenges. Motivated by this, we present a new forward model for the continuum emission of AM CVn binaries that connects source binary parameters to X-ray, optical, and ultraviolet observables. The model assumes GW-driven mass transfer with physically motivated prescriptions for accretion energetics, emission geometry, absorption, and instrumental response. Combining this with $\textit{LISA}$ observations and the output of binary population synthesis enables exploration of the multi-messenger properties of AM CVns. Although uncertain, our model predicts that approximately one per $7000$ AM CVn binaries will permit a joint multi-messenger detection with $\textit{LISA}$, $\textit{CASTOR}$, and $\textit{AXIS}$. We also develop a framework for inferring binary parameters from the inverse model with a convolutional neural net and normalizing flows. Testing the trained flow with our synthetic AM CVn population, we find mean absolute fractional error on the inferred accretor mass of $0.05$, donor mass of $0.26$, orbital period of $0.1$, and distance of $0.2$, while Spearman's rank shows strongly correlated true and predicted distributions except for the donor mass. These efforts lay a foundation for follow-up studies that will explore detailed binary astrophysics and observational requirements for effective multi-messenger scientific discovery in the coming decade.

astro-ph.HE↗

arXiv2026

JWST Observations of the Double Nucleus in NGC 4486B: Possible Evidence for a Recent Binary SMBH Merger and Recoil

A recent study of the compact elliptical galaxy NGC 4486B using JWST-NIRSpec IFU kinematics confirmed a supermassive black hole (SMBH) of mass $M_{BH}=3.6\pm0.7\times10^8$ (~8% of the stellar mass). In addition to its double nucleus, the nuclear kinematics show pronounced asymmetries: a velocity-dispersion peak displaced by 6 pc from the galaxy center and a ~16 km/s offset in the mean stellar line-of-sight velocity near the SMBH. We examine the origin of the 12 pc double nucleus and these asymmetries and show that the observations favor an SMBH surrounded by an eccentric nuclear disk (END). END formation models require the SMBH to experience a gravitational wave (GW) recoil following a binary SMBH merger. Our orbit-superposition models contain ~50% retrograde stars at the edge of the nuclear region, in striking agreement with END-formation simulations. We infer a pre-merger mass ratio q>0.15 and a recoil kick of ~340 km/s. Our N-body simulations show that with such a kick, the SMBH returns to the center within ~30 Myr. Its flat central core is also consistent with earlier binary black hole scouring. We test two alternative mechanisms-buoyancy-driven oscillations and a pre-merger SMBH binary-but neither reproduces the observed offsets, favoring the GW-kick scenario. Our direct N-body simulations further show that a prograde SMBH binary in a rotating host can stall in a corotation resonance, delaying coalescence. Thus, although NGC 4486B is an old, relaxed galaxy near the Virgo cluster center, its SMBH appears to have merged only recently, making its nucleus a rare nearby laboratory for studying post-merger SMBH dynamics.

astro-ph.GA↗

arXiv2025

The Next Generation Virgo Cluster Survey (NGVS). XL. The Morphological Classification of Virgo Cluster Galaxies

We present a study of morphologies, based on deep $u^{*}g^{\prime}i^{\prime}z^{\prime}$ imaging of the Virgo Cluster from the Next Generation Virgo Cluster Survey (NGVS), for 3689 Virgo cluster members spanning a mass range of $\sim$$10^{11}M_{\odot}$ to $\sim$$10^5~M_{\odot}$. Our analysis introduces a new, two-component visual classification scheme developed to capture the morphological diversity of galaxies over more than six orders of magnitude in stellar mass. Our morphological classifications use two parameters to describe the global structure and star formation activity of each galaxy. Structural sub-codes denote features such as spiral arms, bars, disks, shells, streams, while star formation sub-codes indicate the form and location of the current star formation activity (e.g., in cores, clumps, filaments, etc). These visual classifications rely on deep $g^\prime$-band images, supplemented by $u^{*}g^{\prime}i^{\prime}$ color images, as well as unsharp-masked images for a subset of objects. We compare our classifications to previous results for bright member galaxies that used more established schemes, finding good agreement. We also measure quantitative classification statistics (e.g., CASGM$_{20}$) for a subset of the brighter galaxies, and present catalogs for some galaxy types of special interest, including structurally compact galaxies, ultra-diffuse galaxies, candidate ultra-compact dwarf transition objects, as well as candidate post-merger systems. These morphological classifications may be useful as a training set in the application of machine learning tools to the next generation of wide-field imaging surveys.

astro-ph.GA↗

arXiv2025

A Supermassive Black Hole in a Diminutive Ultra-compact Dwarf Galaxy Discovered with JWST/NIRSpec+IFU

The integral-field unit mode of the Near-Infrared Spectrograph (NIRSpec+IFU) mounted on the James Webb Space Telescope has now enabled kinematic studies of smaller and less massive compact stellar systems in which to search for central massive black holes (BHs) than ever before. We present here the first such detection using NIRSpec+IFU in its highest resolution (R~2700) mode. We report a $3σ$ detection of a central black hole with mass ${\cal M}_{BH}=2.2\pm1.1\times10^6\,M_\odot$ in UCD736 orbiting within the Virgo galaxy cluster based on Schwarzschild's modeling of the 1D kinematic profile. The presence of such a massive BH strongly argues against a globular cluster origin of this UCD, and rather suggests a tidally stripped formation route from a former $\gtrsim10^9\,M_\odot$ dwarf galaxy host. Two other methods produce results consistent with Schwarzschild's modelling, but can only provide upper-limits on ${\cal M}_{BH}$. This represents the detection of a BH in the most compact ($r_h\approx15\,{\rm pc}$) stellar system to date, with a ${\cal M}_{BH}$ corresponding to ~9 percent of the system's stellar mass, roughly in line with previously reported UCD BH detections and comparable to the BH detected in the compact elliptical galaxy NGC4486B.

astro-ph.GA↗

arXiv2025

Rotating Supermassive Pop III Stars On The Main Sequence

The detection of billion-solar-mass supermassive black holes (SMBHs) within the first billion years of cosmic history challenges conventional theories of black hole formation and growth. Simultaneously, recent JWST observations revealing exceptionally high nitrogen-to-oxygen abundance ratios in galaxies at high redshifts raise critical questions about rapid chemical enrichment mechanisms operating in the early universe. Supermassive stars (SMSs) with masses of 1000 to 10000 M$_{\odot}$ are promising candidates to explain these phenomena, but existing models have so far neglected the pivotal role of stellar rotation. Here, we present the first comprehensive evolutionary models of rotating Pop III SMSs computed using the GENEC stellar evolution code, including detailed treatments of rotation-induced chemical mixing, angular momentum transport, and mass loss driven by the $ΩΓ$ limit. We demonstrate that rotation significantly enlarges the convective core and extends stellar lifetimes by up to 20%, with moderate enhancement of mass-loss rates as stars approach critical rotation thresholds. Our results further indicate that the cores of SMSs rotate relatively slowly (below $\sim 200$ km s$^{-1}$), resulting in dimensionless spin parameters $a* < 0.1$ for intermediate-mass black hole (IMBH) remnants that are notably lower than theoretical maximum spins. These findings highlight rotation as a key factor in determining the structural evolution, chemical yields, and black hole spin properties of SMSs, providing critical insights to interpret observational signatures from the high-redshift universe.

astro-ph.SR↗

arXiv2025

A JWST View of the Overmassive Black Hole in NGC 4486B

We present a new stellar dynamical measurement of the supermassive black hole (SMBH) in the compact elliptical galaxy NGC 4486B, based on integral field spectroscopy with JWST/NIRSpec. The two-dimensional kinematic maps reveal a resolved double nucleus and a velocity dispersion peak offset from the photometric center. Utilizing two independent methods-Schwarzschild orbit-superposition and Jeans Anisotropic Modeling-we tightly constrain the black hole mass by fitting the full line-of-sight velocity distribution. Our axisymmetric Schwarzschild models yield a best-fit black hole mass of $M_{BH} = 3.6^{+0.7}_{-0.7} \times 10^8 \, M_{\odot}$, slightly lower but significantly more precise than previous estimates. However, since our models do not account for the non-equilibrium nature of the double nucleus, this value may represent a lower limit. Across all tested dynamical models, the inferred $M_{BH}/M_*$ ratio ranges from ~ 4-13%, providing robust evidence for an overmassive SMBH in NGC 4486B. Combined with the galaxy's location deep within the Virgo Cluster, our results support the interpretation that NGC 4486B is the tidally stripped remnant core of a formerly massive galaxy. As the JWST/NIRSpec field of view is insufficient to constrain the dark matter halo, we incorporate archival ground-based long-slit kinematics extending to 5 arcsec. While this provides some leverage on the dark matter content, the constraints remain relatively weak. We place only an upper limit on the dark matter fraction, with $M_{DM}/M_{*} < 0.5$ within 1 kpc-well beyond the effective radius. The inferred black hole mass remains unchanged with or without a dark matter halo.

astro-ph.GA↗

arXiv2025

FORECASTOR -- II. Simulating Galaxy Surveys with the Cosmological Advanced Survey Telescope for Optical and UV Research

The Cosmological Advanced Survey Telescope for Optical and UV Research (CASTOR) is a planned flagship space telescope, covering the blue-optical and UV part of the spectrum. Here we introduce the CASTOR image simulator, a Python GalSim package-based script capable of generating mock CASTOR images from an input catalogue. We generate example images from the CASTOR Wide, Deep, and Ultra-Deep surveys using simulated light-cones from the Santa Cruz Semi-Analytic Model. We make predictions for the performance of these surveys by comparing galaxies that are extracted from each image using Source Extractor to the input catalogue. We find that the Wide, Deep, and Ultra-Deep surveys will be 75% complete for point sources down to ~27, 29 and 30 mag, respectively, in the UV, u, and g filters, with the UV-split and u-split filters reaching a shallower depth. With a large area of ~2200 deg$^2$, the Wide survey will detect hundreds of millions of galaxies out to z~4, mostly with $M_\ast \gtrsim 10^9 M_\odot$. The Ultra-Deep survey will probe to z~5, detecting galaxies with $M_\ast \gtrsim 10^7 M_\odot$. These galaxy samples will enable precision measurements of the distribution of star formation in the cosmic web, connecting the growth of stellar mass to the assembly of dark matter halos over two thirds of the history of the Universe, and other core goals of CASTOR's legacy surveys. These image simulations and the tools developed to generate them will be a vital planning tool to estimate CASTOR's performance and iterate the telescope and survey designs prior to launch.

astro-ph.GA↗

arXiv2024

FORECASTOR -- I. Finding Optics Requirements and Exposure times for the Cosmological Advanced Survey Telescope for Optical and UV Research mission

The Cosmological Advanced Survey Telescope for Optical and ultraviolet Research (CASTOR) is a proposed Canadian-led 1m-class space telescope that will carry out ultraviolet and blue-optical wide-field imaging, spectroscopy, and photometry. CASTOR will provide an essential bridge in the post-Hubble era, preventing a protracted UV-optical gap in space astronomy and enabling an enormous range of discovery opportunities from the solar system to the nature of the Cosmos, in conjunction with the other great wide-field observatories of the next decade (e.g., Euclid, Roman, Vera Rubin). FORECASTOR (Finding Optics Requirements and Exposure times for CASTOR) will supply a coordinated suite of mission-planning tools that will serve as the one-stop shop for proposal preparation, data reduction, and analysis for the CASTOR mission. We present the first of these tools: a pixel-based, user-friendly, extensible, multi-mission exposure time calculator (ETC) built in Python, including a modern browser-based graphical user interface that updates in real time. We then provide several illustrative examples of FORECASTOR's use that advance the design of planned legacy surveys for the CASTOR mission: a search for the most massive white dwarfs in the Magellanic Clouds; a study of the frequency of flaring activity in M stars, their distribution and impacts on habitability of exoplanets; mapping the proper motions of faint stars in the Milky Way; wide and deep galaxy surveys; and time-domain studies of active galactic nuclei.

astro-ph.IM↗

arXiv2024

Explaining the high nitrogen abundances observed in high-z galaxies via population III stars of a few thousand solar masses

The chemical enrichment of the early Universe is a crucial element in the formation and evolution of galaxies, and Population III (PopIII) stars must play a vital role in this process. In this study, we examine metal enrichment from massive stars in the early Universe's embryonic galaxies. Using radiation hydrodynamic simulations and stellar evolution modelling, we calculated the expected metal yield from these stars. Specifically, we applied accretion rates from a previous radiation-hydrodynamic simulation to inform our stellar evolution modelling, executed with the Geneva code, across 11 selected datasets, with final stellar masses between 500 and 9000 Msol. Our results demonstrate that the first generation of Pop III stars within a mass range of 2000 to 9000 Msol result in N/O, C/O and O/H ratios compatible with the values observed in very high-z galaxies GN-z11 and CEERS 1019. The ejecta of these Pop III stars are predominantly composed of He, H, and N. Our Pop III chemical enrichment model of the halo can accurately reproduce the observed N/O and C/O ratios, and, by incorporating a hundred times more zero-metallicity interstellar material with the stellar ejecta, it accurately attains the observed O/H ratio. Thus, a sub-population of extremely massive PopIII stars, with masses surpassing approximately 2000 Msol, effectively reproduces the CNO elemental abundances observed in high-z JWST galaxies to date.

astro-ph.GA↗

arXiv2024

Probing the Diversity of Type Ia Supernova Light Curves in the Open Supernova Catalog

The ever-growing sample of observed supernovae enhances our capacity for comprehensive supernova population studies, providing a richer dataset for understanding the diverse characteristics of Type Ia supernovae and possibly that of their progenitors. Here, we present a data-driven analysis of observed Type Ia supernova photometric light curves collected in the Open Supernova Catalog. Where available, we add the environmental information from the host galaxy. We focus on identifying sub-classes of Type Ia supernovae without imposing the pre-defined sub-classes found in the literature to date. To do so, we employ an implicit-rank minimizing autoencoder neural network for developing low-dimensional data representations, providing a compact representation of the supernova light curve diversity. When we analyze light curves alone, we find that one of our resulting latent variables is strongly correlated with redshift, allowing us to approximately ``de-redshift'' the other latent variables describing each event. After doing so, we find that three of our latent variables account for $\sim$95\% of the variance in our sample, and provide a natural separation between 91T and 91bg thermonuclear supernovae. Of note, the 02cx subclass is not unambiguously delineated from the 91bg sample in our results, nor do either the over-luminous 91T or the under-luminous 91bg/02cx samples form a clearly distinct population from the broader sample of ``other'' SN Ia events. We identify the physical characteristics of supernova light curves which best distinguish SNe 91T from SNe 91bg \& 02cx, and discuss prospects for future refinements and applications to other classes of supernovae as well as other transients.

astro-ph.IM↗

arXiv2023

Critical accretion rates for rapidly growing massive Population III stars

Efforts to understand the origin and growth of massive black holes observed in the early Universe have spurred a strong interest in the evolution and fate of rapidly-accreting primordial (metal-free) stars. Here, we investigate the evolution of such Population III stars under variable accretion rates, focusing on the thermal response and stellar structure, the impact of the luminosity wave encountered early in the pre-main sequence phase, and the influence of accretion on their subsequent evolution. We employ the Geneva stellar evolution code and simulate ten models with varying accretion histories, covering a final mass range from 491 M$_{\odot}$ to 6127 M$_{\odot}$. Our findings indicate that the critical accretion rate delineating the red and blue supergiant regimes during the pre-main sequence evolution is approximately $2.5\times10^{-2} $M$_{\odot}$/yr. Once core hydrogen burning commences, the value of this critical accretion rate drops to $7.0\times10^{-3}$M$_{\odot}$/yr. Moreover, we also confirm that the Kelvin-Helmholtz timescale in the outer surface layers is the more relevant timescale for determining the transition between red and blue phases. Regarding the luminosity wave, we find that it affects only the early pre-main sequence phase of evolution and does not directly influence the transition between red and blue phases, which primarily depends on the accretion rate. Finally, we demonstrate that variable accretion rates significantly impact the lifetimes, surface enrichment, final mass and time spent in the red phase. Our study provides a comprehensive understanding of the intricate evolutionary patterns of Population III stars subjected to variable accretion rates.

astro-ph.SR↗

arXiv2023

The Evolution of Population III and Extremely Metal-Poor Binary Stars

Numerical simulations have now shown that Population III (Pop III) stars can form in binaries and small clusters and that these stars can be in close proximity to each other. If so, they could be subject to binary interactions such as mass exchange that could profoundly alter their evolution, ionizing UV and Lyman-Werner (LW) photon emission and explosion yields, with important consequences for early cosmological reionization and chemical enrichment. Here we investigate the evolution of Pop III and extremely metal-poor binary stars with the MESA code. We find that interactions ranging from stable mass transfer to common envelope evolution can occur in these binaries for a wide range of mass ratios and initial separations. Mass transfer can nearly double UV photon yields in some of these binaries with respect to their individual stars by extending the life of the companion star, which in turn can enhance early cosmological reionization but also suppress the formation of later generations of primordial stars. Binary interactions can also have large effects on the nucleosynthetic yields of the stars by promoting or removing them into or out of mass ranges for specific SN types. We provide fits to total photon yields for the binaries in our study for use in cosmological simulations.

astro-ph.SR↗

arXiv2023

3D hydrodynamics simulations of core convection in supermassive main-sequence stars

Supermassive stars are Population III stars with masses exceeding $10^4\,M_{\odot}$ that could be the progenitors of the first supermassive black holes. Their interiors are in a regime where radiation pressure dominates the equation of state. In this work, we use the explicit gas dynamics code PPMstar to simulate the hydrogen-burning core of a $10^4\,M_{\odot}$ supermassive main-sequence star. These are the first 3D hydrodynamics simulations of core convection in supermassive stars. We perform a series of ten simulations at different heating rates and on Cartesian grids with resolutions of $768^3$, $1152^3$ and $1728^3$. We examine different properties of the convective flow, including its large-scale morphology, its velocity spectrum and its mixing properties. We conclude that the radiation pressure-dominated nature of the interior does not noticeably affect the behaviour of convection compared to the case of core convection in a massive main-sequence star where gas pressure dominates. Our simulations also offer support for the use of mixing-length theory in 1D models of supermassive stars.

astro-ph.SR↗

arXiv2023

Modeling Supermassive Primordial Stars with MESA

Supermassive stars forming at $z \sim$ 15 - 20 are one of the leading contenders for the origin of the first quasars, over 200 of which have now been discovered at $z >$ 6. These stars likely form in pristine, atomically cooled haloes immersed in strong Lyman-Werner UV backgrounds or in highly supersonic baryon streaming flows. Atomic cooling triggers catastrophic baryon collapse capable of building up stars at rates of up to $\sim$1 M$_{\odot}$ yr$^{-1}$. Here we examine the evolution of supermassive stars with a much larger and finer grid of accretion rates than in previous studies with the \texttt{MESA} stellar evolution code. We find that their final masses range from 3.5 $\times$ 10$^3$ M$_{\odot}$ - 3.7 $\times$ 10$^5$ M$_{\odot}$ at accretion rates of 0.001 M$_{\odot}$ yr$^{-1}$ - 1 M$_{\odot}$ yr$^{-1}$, respectively. We also find that supermassive star evolution diverges at accretion rates of 0.01 M$_{\odot}$ yr$^{-1}$ - 0.02 M$_{\odot}$ yr$^{-1}$, above which they evolve as cool red hypergiants along the Hayashi track and collapse via the general relativistic instability during central hydrogen burning, and below which they evolve as hot blue supergiants and collapse at the end of their nuclear burning lifetimes after exiting the main sequence.

astro-ph.SR↗

arXiv2022

Turbulent Cold Flows Gave Birth to the First Quasars

How quasars powered by supermassive black holes (SMBHs) formed less than a billion years after the Big Bang is still one of the outstanding problems in astrophysics 20 years after their discovery$^{1-4}$. Cosmological simulations suggest that rare cold flows converging on primordial haloes in low-shear environments could have created these quasars if they were 10$^4$ - 10$^5$ M$_{\odot}$ at birth but could not resolve their formation$^{5-8}$. Semianalytical studies of the progenitor halo of a primordial quasar found that it favours the formation of such seeds but could not verify if one actually appeared$^9$. Here we show that a halo at the rare convergence of strong, cold accretion flows creates massive BH seeds without the need for UV backgrounds, supersonic streaming motions, or even atomic cooling. Cold flows drive violent, supersonic turbulence in the halo that prevents star formation until it reaches a mass that triggers sudden, catastrophic baryon collapse that forms 31,000 and 40,000 M$_{\odot}$ stars. This simple, robust process ensures that haloes capable of forming quasars by z $>$ 6 produce massive seeds. The first quasars were thus a natural consequence of structure formation in cold dark matter cosmologies, not exotic, finely-tuned environments as previously thought$^{10-14}$.

astro-ph.GA↗

arXiv2021

On the Formation and Interaction of Multiple Supermassive Stars in Cosmological Flows

Supermassive primordial stars with masses exceeding $\sim10^5\,M_{\odot}$ that form in atomically cooled halos are the leading candidates for the origin of high-redshift quasars with $z>6$. Recent numerical simulations, however, find that multiple accretion disks can form within a halo, each of which can host a supermassive star. Tidal interactions between the disks can gravitationally torque gas onto their respective stars and alter their evolution. Later, when two satellite disks collide, the two stars can come into close proximity. This may induce additional mass exchange between them. We investigate the co-evolution of supermassive stars in atomically-cooled halos driven by gravitational interactions between their disks. We find a remarkable diversity of evolutionary outcomes. The results depend on these interactions and how the formation and collapse times of the stars in the two disks are correlated. They range from co-evolution as main sequence stars to main sequence -- black hole pairs and black hole -- black hole mergers. We examine the evolution of these secondary supermassive stars in detail and discuss the prospects for binary interactions on much smaller scales after the disks merge within their host halos.

astro-ph.GA↗

arXiv2021

Some First Stars Were Red: Detecting Signatures of Massive Population III Formation Through Long-Term Stochastic Color Variations

Identifying stars formed in pristine environments (Pop III) within the first billion years is vital to uncovering the earliest growth and chemical evolution of galaxies. Pop III galaxies, however, are typically expected to be too faint and too few in number to be detectable by forthcoming instruments without extremely long integration times and/or extreme lensing. In an environment, however, where star formation is suppressed until a halo crosses the atomic cooling limit (e.g., by a modest Lyman-Werner flux, high baryonic streaming velocities, and/or dynamical heating effects),primordial halos can form substantially more numerous and more massive stars. Some of these stars will in-turn be accreting more rapidly than they can thermally relax at any given time. Using high resolution cosmological zoom-in simulations of massive star formation in high-z halos, we find that such rapidly accreting stars produce prominent spectral features which would be detectable by {\it JWST}. The rapid accretion episodes within the halo lead to stochastic reprocessing of 0--20\% of the total stellar emission into the rest-frame optical over long timescales, a unique signature which may allow deep observations to identify such objects out to $z \sim 10-13$ using mid- and wide-band NIRCam colors alone.

astro-ph.GA↗