@article{21725, abstract = {The initial–final mass relation (IFMR) links a star’s birth mass to the mass of its white dwarf (WD) remnant, providing key constraints on stellar evolution. Open clusters offer the most straightforward way to empirically determine the IFMR, as their well-defined ages allow for direct progenitor lifetime estimates. We construct the most comprehensive open cluster WD IFMR to date by combining new spectroscopy of 22 WDs with an extensive literature review of WDs with strong cluster associations. To minimize systematics, we restrict our analysis to spectroscopically confirmed hydrogen-atmosphere (DA) WDs consistent with single-stellar origins. We separately analyze a subset with reliable Gaia-based astrometric membership assessments, as well as a full sample that adds WDs with strong cluster associations whose membership cannot be reliably assessed with Gaia. The Gaia-based sample includes 69 spectroscopically confirmed DA WDs, more than doubling the sample size of previous Gaia-based open cluster IFMRs. The full sample, which includes 53 additional literature WDs, increases the total number of cluster WDs by over 50% relative to earlier works. We provide functional forms for both the Gaia-based and full-sample IFMRs. The Gaia-based result useful for Mi � 2.67 M⊙ is Mf = [0.179 0.100H (Mi 3.84 M )] × (Mi 3.84 M ) + 0.628 M , where H(x) is the Heaviside step function. Comparing our IFMR to recent literature, we identify significant deviations from best-fit IFMRs derived from both Gaia-based volume-limited samples of field WDs and double WD binaries, with the largest discrepancy occurring for initial masses of about 5 M⊙.}, author = {Miller, David R. and Caiazzo, Ilaria and Heyl, Jeremy and Richer, Harvey B. and Hollands, Mark A. and Tremblay, Pier Emmanuel and El-Badry, Kareem and Rodriguez, Antonio C. and Vanderbosch, Zachary P.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, keywords = {White dwarf stars, Open star clusters, Compact objects, Stellar evolution}, number = {1}, publisher = {IOP Publishing}, title = {{The White Dwarf initial–final mass relation from open clusters in Gaia DR3}}, doi = {10.3847/1538-4357/ae18c8}, volume = {996}, year = {2026}, } @article{20217, abstract = {We present Virgil, a Mid-Infrared Instrument (MIRI) extremely red object detected with the F1000W filter as part of the MIRI Deep Imaging Survey observations of the Hubble Ultra Deep Field. Virgil is an Lyα emitter (LAE) at zspec = 6.6312 ± 0.0019 (from the Very Large Telescope/MUSE) with a rest-frame UV-to-optical spectral energy distribution (SED) typical of LAEs at similar redshifts. However, MIRI observations reveal an unexpected extremely red color at rest-frame near-infrared (NIR) wavelengths, F444W − F1000W = 2.33 ± 0.06. Such a steep rise in the NIR, completely missed without MIRI imaging, is poorly reproduced by models including only stellar populations and hints toward the presence of an active galactic nucleus, although alternative explanations such as extreme dust obscuration and strong nebular continuum and emission lines contribution due to young stellar ages cannot be completely ruled out. According to the shape of its overall SED, Virgil belongs to the recently discovered population of little red dots but displays an extended rest-frame UV-optical wavelength morphology following a 2DSérsic profile with an average index of n = 0.93+0.85_0.31 and re = 0.49+0.05_0.11 pkpc. Only at MIRI wavelengths, Virgil is unresolved due to the coarser point-spread function. This discovery demonstrates the crucial importance of deep MIRI surveys to reveal the true nature and properties of high-z galaxies that otherwise would be misinterpreted and raises the question of how common Virgil-like objects could be in the early Universe.}, author = {Iani, Edoardo and Rinaldi, Pierluigi and Caputi, Karina I. and Annunziatella, Marianna and Langeroodi, Danial and Melinder, Jens and Pérez-González, Pablo G. and Álvarez-Márquez, Javier and Boogaard, Leindert A. and Bosman, Sarah E.I. and Costantin, Luca and Moutard, Thibaud and Colina, Luis and Östlin, Göran and Greve, Thomas R. and Wright, Gillian and Alonso-Herrero, Almudena and Bik, Arjan and Gillman, Steven and Crespo Gómez, Alejandro and Hjorth, Jens and Kendrew, Sarah and Labiano, Alvaro and Pye, John P. and Tikkanen, Tuomo V. and Walter, Fabian and Güdel, Manuel and Henning, Thomas and Van Der Werf, Paul P.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{MIDIS: MIRI uncovers Virgil, the first Little Red Dot with clear detection of its host galaxy at z ≃ 6.6}}, doi = {10.3847/1538-4357/ade5a6}, volume = {989}, year = {2025}, } @article{20586, abstract = {We present the discovery of deep, irregular, periodic transits toward the white dwarf ZTF J1944+4557 using follow-up time-series photometry and spectroscopy from Palomar, Keck, McDonald, Perkins, and Lowell observatories. We find a predominant period of 4.9704 hr, consistent with an orbit near the Roche limit of the white dwarf, with individual dips over 30% deep and lasting between 15 and 40 minutes. Similar to the first known white dwarf with transiting debris, WD 1145+017, the transit events are well-defined with prominent out-of-transit phases where the white dwarf appears unobscured. Spectroscopy concurrent with transit photometry reveals that the average Ca K equivalent width remains constant in and out of transit. The broadening observed in several absorption features cannot be reproduced by synthetic photospheric models, suggesting the presence of circumstellar gas. Simultaneous g + r- and g + i-band light curves from the CHIMERA instrument reveal no color dependence to the transit depths, requiring transiting dust grains to have sizes s ≳ 0.2 μm. The transit morphologies appear to be constantly changing at a rate faster than the orbital period. Overall transit activity varies in the system, with transit features completely disappearing during the seven months between our 2023 and 2024 observing seasons and then reappearing in 2025 March, still repeating at 4.9704 hr. Our observations of the complete cessation and resumption of transit activity provide a novel laboratory for constraining the evolution of disrupted debris and processes like disk exhaustion and replenishment timescales at white dwarfs.}, author = {Guidry, Joseph A. and Vanderbosch, Zachary P. and Hermes, J. J. and Veras, Dimitri and Hollands, Mark A. and Bhattacharjee, Soumyadeep and Caiazzo, Ilaria and El-Badry, Kareem and Kao, Malia L. and Ould Rouis, Lou Baya and Rodriguez, Antonio C. and Van Roestel, Jan}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{Transiting planetary debris near the Roche limit of a white dwarf on a 4.97 hr orbit—and its vanishing}}, doi = {10.3847/1538-4357/adfecb}, volume = {992}, year = {2025}, } @article{19365, abstract = {We present a comprehensive analysis of H i absorption around 96 Lyα emitters (LAEs) at z ≈ 3.3 (median Lyα luminosity ≈1042 erg s−1). These LAEs were identified within eight MUSE fields, each (math. formular) on the sky and centered on a bright background quasar, as part of the MUSEQuBES survey. Using Voigt profile fitting for all H i absorbers detected within ±​​​​​​500 km s−1 of these LAEs, we compiled a catalog of 800 H i absorption components. Our analysis shows that H i absorption is enhanced near the LAEs compared to the intergalactic medium. However, no trend is found between the column densities of H i absorbers and their impact parameters from the LAEs (spanning ​​​​​​≈54–260 pkpc). Additionally, all galaxies associated with Lyman-limit systems have impact parameters >50 pkpc from the quasar sightlines, suggesting that true absorber hosts may be too faint to detect. The LAEs show an overall H i covering fraction (fc(H i)) of ≈88% for a threshold (math. formular) (H i) = 15. Notably, at the same threshold, the LAEs in pairs/groups exhibit a 100% H i covering fraction out to ≈250 pkpc. In contrast, isolated LAEs consistently show a lower fc(H i) of ≈80%. This environmental influence on fc(H i) is also evident up to ≈300 km s−1 in differential bins of line-of-sight velocity. We find an anticorrelation between fc(H i) and the equivalent width of rest-frame Lyα emission (EW0). Based on the Lyα shell model, this could imply that gas-rich galaxies tend to reside in gas-rich environments or that the LAEs with higher EW0 are more efficient at ionizing their surrounding medium.}, author = {Banerjee, Eshita and Muzahid, Sowgat and Schaye, Joop and Blaizot, Jérémy and Bouché, Nicolas and Cantalupo, Sebastiano and Johnson, Sean D. and Matthee, Jorryt J and Verhamme, Anne}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{MUSEQuBES: Connecting H i Absorption with Lyα emitters at z ≈ 3.3}}, doi = {10.3847/1538-4357/ada7e9}, volume = {980}, year = {2025}, } @article{19596, abstract = {We report the spectroscopic discovery of a massive quiescent galaxy at zspec = 7.29 ± 0.01, just ∼700 Myr after the big bang. RUBIES-UDS-QG-z7 was selected from public JWST/NIRCam and MIRI imaging from the PRIMER survey and observed with JWST/NIRSpec as part of RUBIES. The NIRSpec/PRISM spectrum reveals one of the strongest Balmer breaks observed thus far at z > 6, with no emission lines but tentative Balmer and Ca absorption features, as well as a Lyman break. Simultaneous modeling of the NIRSpec/PRISM spectrum and NIRCam and MIRI photometry (spanning 0.9–18 μm) shows that the galaxy formed a stellar mass of (math. formular) before z ∼ 8 and ceased forming stars 50–100 Myr prior to the time of observation, resulting in log (sSFR/Gyr- 1) < -1 . We measure a small physical size of (math formular) , which implies a high stellarmass surface density within the effective radius of (math formular) comparable to the highest densities measured in quiescent galaxies at z ∼ 2–5. The 3D stellar-mass density profile of RUBIES-UDS-QG-z7 is remarkably similar to the central densities of local massive ellipticals, suggesting that at least some of their cores may have already been in place at z > 7. The discovery of RUBIES-UDS-QG-z7 has strong implications for galaxy formation models: the estimated number density of quiescent galaxies at z ∼ 7 is >100 × larger than predicted from any model to date, indicating that quiescent galaxies have formed earlier than previously expected. }, author = {Weibel, Andrea and De Graaff, Anna and Setton, David J. and Miller, Tim B. and Oesch, Pascal A. and Brammer, Gabriel and Lagos, Claudia D.P. and Whitaker, Katherine E. and Williams, Christina C. and Baggen, Josephine F.W. and Bezanson, Rachel and Boogaard, Leindert A. and Cleri, Nikko J. and Greene, Jenny E. and Hirschmann, Michaela and Hviding, Raphael E. and Kuruvanthodi, Adarsh and Labbé, Ivo and Leja, Joel and Maseda, Michael V. and Matthee, Jorryt J and Mcconachie, Ian and Naidu, Rohan P. and Roberts-Borsani, Guido and Schaerer, Daniel and Suess, Katherine A. and Valentino, Francesco and Van Dokkum, Pieter and Wang, Bingjie}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{RUBIES reveals a massive quiescent galaxy at z = 7.3}}, doi = {10.3847/1538-4357/adab7a}, volume = {983}, year = {2025}, } @article{19699, abstract = {We demonstrate that gas disks around binary systems might deliver gas to the binary components only when the circumbinary disk is relatively warm. We present new grid-based hydrodynamics simulations, performed with the binary on the grid and a locally isothermal equation of state, in which the binary is seen to functionally "stop accreting" if the orbital Mach number in the disk exceeds a threshold value of about 40. Above this threshold, the disk continues to extract angular momentum from the binary orbit, but it delivers very little mass to the black holes and instead piles up mass in a ring surrounding the binary. This ring will eventually become viscously relaxed and deliver mass to the binary at the large-scale inflow rate. However, we show that the timescale for such relaxation can far exceed the implied binary lifetime. We demonstrate that the ability of a binary–disk system to equilibrate is dependent on the efficiency at which accretion streams deposit mass onto the binary, which, in turn is highly sensitive to the thermodynamic conditions of the inner disk. If disks around massive black hole binaries do operate in such nonaccreting regimes, it suggests these systems may be dimmer than their single black hole counterparts but could exhibit dramatic rebrightening after the black holes inspiral and merge. This dimming begins in the UV/optical and could completely choke high-energy emission, such that these systems would likely be intrinsically X-ray weak with reddened continua, potentially resembling the spectra of "little red dots" recently identified in JWST observations.}, author = {Tiede, Christopher and Zrake, Jonathan and Macfadyen, Andrew and Haiman, Zoltán}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{Suppressed accretion onto massive black hole binaries surrounded by thin disks}}, doi = {10.3847/1538-4357/adc727}, volume = {984}, year = {2025}, } @article{19700, abstract = {The JWST discovery of "little red dots" (LRDs) is reshaping our picture of the early Universe, yet the physical mechanisms driving their compact size and UV-optical colors remain elusive. Here, we report an unusually bright LRD (zspec = 3.1) observed as part of the RUBIES program. This LRD exhibits broad emission lines (FWHM ∼ 4000 km s−1), a blue UV continuum, a clear Balmer break, and a red continuum sampled out to rest-frame 4 μm with MIRI. We develop a new joint galaxy and active galactic nucleus (AGN) model within the Prospector Bayesian inference framework and perform spectrophotometric modeling using NIRCam, MIRI, and NIRSpec/Prism observations. Our fiducial model reveals a M* ∼ 109 M⊙ galaxy alongside a dust-reddened AGN driving the optical emission. Explaining the rest-frame optical color as a reddened AGN requires AV ≳ 3, suggesting that a great majority of the accretion disk energy is reradiated as dust emission. Yet, despite clear AGN signatures, we find a surprising lack of hot torus emission, which implies that either the dust emission in this object must be cold, or the red continuum must instead be driven by a massive, evolved stellar population of the host galaxy—seemingly inconsistent with the high-EW broad lines (Hα rest-frame EW ∼ 800 Å). The widths and luminosities of Pa-β, Pa-δ, Pa-γ, and Hα imply a modest black hole mass of MBH ∼ 108 M⊙. Additionally, we identify a narrow blueshifted He i λ 1.083 μm absorption feature in NIRSpec/G395M spectra, signaling an ionized outflow with kinetic energy up to ∼1% the luminosity of the AGN. The low redshift of RUBIES-BLAGN-1, combined with the depth and richness of the JWST imaging and spectroscopic observations, provides a unique opportunity to build a physical model for these so-far mysterious LRDs, which may prove to be a crucial phase in the early formation of massive galaxies and their supermassive black holes.}, author = {Wang, Bingjie and De Graaff, Anna and Davies, Rebecca L. and Greene, Jenny E. and Leja, Joel and Brammer, Gabriel B. and Goulding, Andy D. and Miller, Tim B. and Suess, Katherine A. and Weibel, Andrea and Williams, Christina C. and Bezanson, Rachel and Boogaard, Leindert A. and Cleri, Nikko J. and Hirschmann, Michaela and Katz, Harley and Labbé, Ivo and Maseda, Michael V. and Matthee, Jorryt J and Mcconachie, Ian and Naidu, Rohan P. and Oesch, Pascal A. and Rix, Hans Walter and Setton, David J. and Whitaker, Katherine E.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{RUBIES: JWST/NIRSpec confirmation of an infrared-luminous, broad-line Little Red Dot with an ionized outflow}}, doi = {10.3847/1538-4357/adc1ca}, volume = {984}, year = {2025}, } @article{21057, abstract = {Among the most puzzling early discoveries of JWST are “little red dots” (LRDs), compact red sources that host broad Balmer emission lines, and in many cases exhibit a “V-shaped” change in slope in the rest-optical. The physical properties of LRDs currently have order-of-magnitude uncertainties, because models to explain the continuum of these sources differ immensely. Here, we leverage the complete selection of red sources in the RUBIES program, supplemented with public PRISM spectra, to study the origin of this V shape. By fitting a broken power law with a flexible inflection point, we find that a large fraction of red Hα emitters at 2 < z < 6 exhibit a strong change in slope, and that all strong inflections appear associated with the Balmer limit (0.3645 μm). Using a simple model of a reddened active galactic nucleus (AGN) with an unobscured scattered-light component, we demonstrate that the observed V shape in LRDs is unlikely to occur at any specific wavelength if the entire continuum is dominated by light from a power-law AGN continuum. In contrast, models with an intrinsic feature at the Balmer limit, such as those that are dominated by an evolved stellar population, can produce the observed spectral shapes, provided that a reddened component picks up sufficiently redward of the break. While no model can comfortably explain the full LRD spectral energy distribution, the common inflection location suggests that a single component consistently dominates the rest-frame UV optical in LRDs, and that this component is associated with T ∼ 10^4 K hydrogen.}, author = {Setton, David J. and Greene, Jenny E. and de Graaff, Anna and Ma, Yilun 逸伦 and Leja, Joel and Matthee, Jorryt J and Bezanson, Rachel and Boogaard, Leindert A. and Cleri, Nikko J. and Katz, Harley and Labbe, Ivo and Maseda, Michael V. and McConachie, Ian and Miller, Tim B. and Price, Sedona H. and Suess, Katherine A. and van Dokkum, Pieter and Wang 王, Bingjie 冰洁 and Weibel, Andrea and Whitaker, Katherine E. and Williams, Christina C.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{Little Red Dots at an inflection point: Ubiquitous v-shaped turnover consistently occurs at the Balmer limit}}, doi = {10.3847/1538-4357/ae1500}, volume = {995}, year = {2025}, } @article{21061, abstract = {Detecting the first generation of stars, Population III (Pop III), has been a long-standing goal in astrophysics, yet they remain elusive even in the JWST era. Here we present a novel NIRCam-based selection method for Pop III galaxies, and carefully validate it through completeness and contamination simulations. We systematically search ≃ 500 arcmin2 across JWST legacy fields for Pop III candidates, including GLIMPSE, which, assisted by gravitational lensing, has produced JWST’s deepest NIRCam imaging thus far. We discover one promising Pop III galaxy candidate (GLIMPSE-16043) at z=6.50 -0.24 +0.03, a moderately lensed galaxy (µ = + 2.9 -0.2 +0.1) with an intrinsic UV magnitude of MUV= -15.89 -0.14 +0.12. It exhibits key Pop III features: strong Hα emission (rest-frame EW 2810 ± 550 Å); a Balmer jump; no dust (UV slope β = −2.34 ± 0.36); and undetectable metal lines (e.g., [O III]; [O III]/Hβ < 0.44), implying a gas-phase metallicity of Zgas/Z⊙ < 0.5%. These properties indicate the presence of a nascent, metal-deficient young stellar population (<5 Myr) with a stellar mass of ≃105 M⊙. Intriguingly, this source deviates significantly from the extrapolated UV–metallicity relation derived from recent JWST observations at z = 4–10, consistent with UV enhancement by a top-heavy Pop III initial mass function or the presence of an extremely metal-poor active galactic nucleus. We also derive the first observational constraints on the Pop III UV luminosity function at z ≃ 6–7. The volume density of GLIMPSE-16043 (≈10^−4 cMpc−3) is in excellent agreement with theoretical predictions, independently reinforcing its plausibility. This study demonstrates the power of our novel NIRCam method to finally reveal distant galaxies even more pristine than the Milky Way’s most metal-poor satellites, thereby promising to bring us closer to the first generation of stars than we have ever been before.}, author = {Fujimoto, Seiji and Naidu, Rohan P. and Chisholm, John and Atek, Hakim and Endsley, Ryan and Kokorev, Vasily and Furtak, Lukas J. and Pan, Richard and Liu, Boyuan and Bromm, Volker and Venditti, Alessandra and Visbal, Eli and Sarmento, Richard and Weibel, Andrea and Oesch, Pascal A. and Brammer, Gabriel and Schaerer, Daniel and Adamo, Angela and Berg, Danielle A. and Bezanson, Rachel and Bouwens, Rychard and Chemerynska, Iryna and Claeyssens, Adélaïde and Dessauges-Zavadsky, Miroslava and Frebel, Anna and Korber, Damien and Labbe, Ivo and Marques-Chaves, Rui and Matthee, Jorryt J and McQuinn, Kristen B. W. and Muñoz, Julian B. and Natarajan, Priyamvada and Saldana-Lopez, Alberto and Suess, Katherine A. and Volonteri, Marta and Zitrin, Adi}, issn = {1538-4357}, journal = {The Astrophysical Journal}, publisher = {IOP Publishing}, title = {{GLIMPSE: An ultrafaint ≃10^5 M⊙ Pop III galaxy candidate and first constraints on the Pop III UV luminosity function at z ≃ 6–7}}, doi = {10.3847/1538-4357/ade9a1}, volume = {989}, year = {2025}, } @article{21062, abstract = {JWST observations have unveiled faint active galactic nuclei (AGNs) at high redshift that provide insights into the formation of supermassive black holes (SMBHs). However, disentangling their stellar from AGN light is challenging. Here, we use an empirical approach to infer the average stellar mass of five faint broad-line (BL) Hα emitters at z = 4–5 with BH masses ≈6 × 10^6 M⊙, with a method independent of their spectral energy distribution (SED). We use the deep JWST/NIRcam grism survey “All the Little Things” to measure the overdensities around BL-Hα emitters and around a spectroscopic reference sample of ∼300 galaxies. In our reference sample, we find that megaparsec-scale overdensity correlates with stellar mass. Their large-scale environments suggest that BL-Hα emitters are hosted by galaxies with stellar masses ≈5 × 10^7 M⊙, ≈40 times lower than those inferred from galaxy-only SED fits. Adding measurements around more luminous z ≈ 6 AGNs, we find tentative correlations between line width, BH mass, and the overdensity, suggestive of a steep BH to halo mass relation. The main implications are (1) when BH masses are taken at face value, we confirm extremely high BH to stellar mass ratios of ≈10%, (2) the galaxies of low stellar mass that host growing SMBHs are in tension with typical hydrodynamical simulations, except those without feedback, (3) a 1% duty cycle implied by the host mass hints at super-Eddington accretion, (4) the masses are at odds with an interpretation of the line broadening in terms of high stellar density, (5) our results imply a luminosity-dependent diversity of galaxy masses, environments, and SEDs among AGN samples.}, author = {Matthee, Jorryt J and Naidu, Rohan P. and Kotiwale, Gauri and Furtak, Lukas J. and Kramarenko, Ivan and Mackenzie, Ruari and Greene, Jenny and Adamo, Angela and Bouwens, Rychard J. and Di Cesare, Claudia and Eilers, Anna-Christina and de Graaff, Anna and Heintz, Kasper E. and Kashino, Daichi and Maseda, Michael V. and Tacchella, Sandro and Torralba Torregrosa, Alberto}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{Environmental evidence for overly massive Black Holes in low-mass galaxies and a Black Hole–Halo mass relation at z ∼ 5}}, doi = {10.3847/1538-4357/ade886}, volume = {988}, year = {2025}, } @article{21123, abstract = {We present a study of the late-time interaction between supermassive black hole binaries and retrograde circumbinary disks during the period of gravitational wave-driven inspiral. While mergers in prograde disks have received extensive study, retrograde disks offer distinct dynamics that could promote mergers and produce unique observational signatures. Through 2D numerical hydrodynamical simulations, we explore the process of binary-disk decoupling, where the binary’s orbital decay rate is faster than the disk’s viscous response rate. We find the point of decoupling to be comparable in prograde and retrograde disks, suggesting that any associated electromagnetic (EM) signatures will be produced at comparable times preceding the merger. However, we find smaller central cavities for retrograde disks, likely leading to higher-frequency EM emissions and shorter postmerger rebrightening timescales compared to their prograde counterparts. Retrograde disks form intrabinary bridges, which are prone to instabilities when the viscosity is low. These instabilities manifest as quasiperiodic flares in the accretion rate, which may produce distinctive EM signatures for retrograde disks.}, author = {O’Neill, David and Tiede, Christopher and D’Orazio, Daniel J. and Haiman, Zoltán and MacFadyen, Andrew}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{Gravitational wave decoupling in retrograde circumbinary disks}}, doi = {10.3847/1538-4357/ae0ca8}, volume = {993}, year = {2025}, } @article{21124, abstract = {The advent of the James Webb Space Telescope (JWST) has opened new horizons in the study of quasar host galaxies during the reionization epoch (z > 6). Building upon our previous initial measurements of stellar light from two quasar host galaxies at these redshifts, we now report the detection of the stellar light from the full Cycle 1 sample of 12 distant moderate-luminosity quasar (M1450 > −24 mag) host galaxies at z > 6 from the Hyper Suprime-Cam Subaru Strategic Program. Using JWST/NIRCam observations at 1.5 and 3.6 μm combined with 2D image decomposition analysis, we successfully detect the host galaxies in 11 of the 12 targets, underscoring the high detection rates achievable with moderate-luminosity quasars. Based on two-band photometry and spectral energy distribution fitting, we find that our host galaxies are massive, with log M*/M⊙ = 9.5–11.0. The effective radii range from 0.6 to 3.2 kpc, comparable to the sizes of inactive galaxies with similar masses at z ∼ 6 as measured with imaging from COSMOS-Web. Intriguingly, the two quasar hosts with post-starburst features, which reside at the high-mass end of our sample and exhibit relatively compact morphologies, have similar size and stellar mass surface densities to quiescent galaxies at z ∼ 4–5. These findings suggest that the so-called galaxy compaction scenario is already in place at the reionization epoch, in which gas inflows during starburst phases drive centrally concentrated star formation followed by rapid quenching, bridging the structural transition of massive galaxies from relatively extended star-forming disks to compact quiescent systems.}, author = {Ding, Xuheng and Onoue, Masafusa and Silverman, John D. and Matsuoka, Yoshiki and Izumi, Takuma and Strauss, Michael A. and Yang, Lilan and Jahnke, Knud and Phillips, Camryn L. and Treu, Tommaso and Andika, Irham T. and Aoki, Kentaro and Arita, Junya and Baba, Shunsuke and Bosman, Sarah E. I. and Eilers, Anna-Christina and Fujimoto, Seiji and Haiman, Zoltán and Imanishi, Masatoshi and Inayoshi, Kohei and Iwasawa, Kazushi and Kartaltepe, Jeyhan and Kashikawa, Nobunari and Kawaguchi, Toshihiro and Li, Junyao and Lee, Chien-Hsiu and Lupi, Alessandro and Schindler, Jan-Torge and Schramm, Malte and Shimasaku, Kazuhiro and Shuntov, Marko and Tanaka, Takumi S. and Toba, Yoshiki and Trakhtenbrot, Benny and Umehata, Hideki and Vestergaard, Marianne and Wang, Feige and Yang, Jinyi}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{SHELLQs-JWST unveils the host galaxies of 12 quasars at z > 6}}, doi = {10.3847/1538-4357/ae045b}, volume = {993}, year = {2025}, } @article{21129, abstract = {Recent hydrodynamical simulations have shown that circumbinary gas disks drive the orbits of massive binary black holes (BHs) to become eccentric, even when general relativistic (GR) corrections to the orbit are significant. Here, we study the GR apsidal precession of eccentric equal-mass massive binary BHs in circumbinary disks via two-dimensional hydrodynamical simulations. We perform a suite of simulations comparing precessing and nonprecessing binaries across a range of eccentricities, semimajor axes, and precession rates. We find that the GR precession of the binary’s semimajor axis can introduce a dominant modulation in the binary’s accretion rate and the corresponding high-energy electromagnetic light curves. We discuss the conditions under which this occurs and its detailed characteristics and mechanism. Finally, we discuss the potential to observe these precession signatures in electromagnetic- and gravitational-wave observations, as well as the precession signal’s unique importance as a potential tool to constrain the mass, eccentricity, and semimajor axis of binary merger events.}, author = {DeLaurentiis, Stanislav and Haiman, Zoltán and Westernacher-Schneider, John Ryan and Krauth, Luke Major and Davelaar, Jordy and Zrake, Jonathan and MacFadyen, Andrew}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{Relativistic binary precession: Impact on eccentric massive binary black hole accretion and hydrodynamics}}, doi = {10.3847/1538-4357/ada612}, volume = {980}, year = {2025}, } @article{21246, abstract = {Stellar astrophysics relies on diverse observational modalities—primarily photometric light curves and spectroscopic data—from which fundamental stellar properties are inferred. While machine learning (ML) has advanced analysis within individual modalities, the complementary information encoded across modalities remains largely underexploited. We present the dual embedding for stellar astronomy (DESA) model, a novel multimodal foundation model that integrates light curves and spectra to learn a unified, physically meaningful latent space for stars. DESA first trains separate modality-specific encoders using a hybrid supervised/self-supervised scheme, and then aligns them through DualFormer, a transformer-based cross-modal integration module tailored for astrophysical data. DualFormer combines cross- and self-attention, a novel dual-projection alignment loss, and a projection-space eigendecomposition that yields physically structured embeddings. We demonstrate that DESA significantly outperforms leading unimodal and self-supervised baselines across a range of tasks. In zero- and few-shot settings, DESA’s learned representations recover stellar color–magnitude and Hertzsprung–Russell diagrams with high fidelity (R2 = 0.92 for photometric regressions). In full fine-tuning, DESA achieves state-of-the-art accuracy for binary star detection (AUC = 0.99, AP = 1.00) and stellar age prediction (RMSE = 0.94 Gyr). As a compelling case, DESA naturally separates synchronized binaries from young stars—two populations with nearly identical light curves—purely from their embedded positions in UMAP space, without requiring external kinematic or luminosity information. DESA thus offers a powerful new framework for multimodal, data-driven stellar population analysis, enabling both accurate prediction and novel discovery.}, author = {Kamai, Ilay and Bronstein, Alexander and Perets, Hagai B.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, publisher = {IOP Publishing}, title = {{Machine Learning inference of stellar properties using integrated photometric and spectroscopic data}}, doi = {10.3847/1538-4357/ae0cbc}, volume = {994}, year = {2025}, } @article{21727, abstract = {We present a comprehensive analysis of the MIRI Extremely Red Object Virgil, a Lyα emitter at zspec = 6.6379 ± 0.0035 with the photometric properties of a Little Red Dot. Leveraging new JWST/MIRI imaging from the MIDIS and PAHSPECS programs, we confirm Virgil’s extraordinary nature among galaxies in JADES/GOODS-South, exhibiting a strikingly red NIRCam-to-MIRI color (F444W–F1500W = 2.84 ± 0.04 mag). Deep NIRSpec/PRISM spectroscopy from the OASIS program offers key insights into the host galaxy, revealing properties of an average star-forming galaxy during Cosmic Reionization, such as a subsolar metallicity, low-to-moderate dust content, and a relatively high ionization parameter and electron temperature. By estimating the star formation rate of Virgil from UV and Hα, we find evidence that the galaxy is either entering or fading out of a bursty episode. Although line-ratio diagnostics employed at high z would classify Virgil as an active galactic nucleus (AGN), this classification becomes ambiguous once redshift evolution is considered. Nonetheless, Virgil occupies the same parameter space as recently confirmed AGNs at similar redshifts. The new deep MIRI data at 15 μm reinforce the AGN nature of Virgil, as inferred from multiple spectral energy distribution (SED) fitting codes. Virgil’s rising infrared SED and UV excess resemble those of Dust-Obscured Galaxies (DOGs) studied with Spitzer at Cosmic Noon, particularly blue-excess HotDOGs. Our results highlight the need for a multiwavelength approach incorporating MIRI to uncover such extreme sources at z ≳ 6 and to shed light on the interplay between galaxy evolution and early black hole growth during Cosmic Reionization.}, author = {Rinaldi, Pierluigi and Pérez-González, Pablo G. and Rieke, George H. and Lyu, Jianwei and D’Eugenio, Francesco and Wu, Zihao and Carniani, Stefano and Looser, Tobias J. and Shivaei, Irene and Boogaard, Leindert A. and Diaz-Santos, Tanio and Colina, Luis and Östlin, Göran and Alberts, Stacey and Álvarez-Márquez, Javier and Annuziatella, Marianna and Aravena, Manuel and Bhatawdekar, Rachana and Bunker, Andrew J. and Caputi, Karina I. and Charlot, Stéphane and Crespo Gómez, Alejandro and Curti, Mirko and Eckart, Andreas and Gillman, Steven and Hainline, Kevin and Kumari, Nimisha and Hjorth, Jens and Iani, Edoardo and Inami, Hanae and Ji, Zhiyuan and Johnson, Benjamin D. and Jones, Gareth C. and Labiano, Álvaro and Maiolino, Roberto and Melinder, Jens and Moutard, Thibaud and Peissker, Florian and Rieke, Marcia and Robertson, Brant and Scholtz, Jan and Tacchella, Sandro and Van Der Werf, Paul P. and Walter, Fabian and Williams, Christina C. and Willott, Chris and Witstok, Joris and Übler, Hannah and Zhu, Yongda}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{Deciphering the nature of Virgil: An obscured active galactic nucleus lurking within an apparently normal Lyα emitter during cosmic reionization}}, doi = {10.3847/1538-4357/ae089c}, volume = {994}, year = {2025}, } @article{21724, abstract = {The next generation of weak-gravitational-lensing surveys has the potential to place stringent constraints on cosmological parameters. However, their analysis is limited by systematics such as the intrinsic alignments of galaxies, which alter weak-lensing convergence and can lead to biases in cosmological parameter estimations. For the first time, in this work, we investigate the impact of intrinsic alignments on non-Gaussian statistics of the weak-lensing field using galaxy shapes derived from the IllustrisTNG hydrodynamical simulation. We create two catalogs of ray-traced convergence maps: one that includes the measured intrinsic shape of each galaxy and another where all galaxies are randomly rotated to eliminate intrinsic alignments. We compare a range of weak-lensing statistics between the two catalogs, including the shear–shear correlation function, the map-level angular power spectrum, one-point, peak count, and minimum distribution functions, and Minkowski functionals. For each statistic, we assess the level of statistical distinguishability between catalogs for a set of future survey angular areas. Our results reveal strong small-scale correlation in the alignment of galaxies and statistically significant boosts in weak-lensing convergence in both positive and negative directions for high-significance peaks and minima, respectively. We note that our analysis is at a fixed number density of ˜ 5 arcmin^-2, drawn from a single realization of initial conditions, and does not include observational uncertainties or supersample covariance contributions. Weak-lensing analyses utilizing non-Gaussian statistics must account for intrinsic alignments to avoid significantly compromised cosmological inferences.}, author = {Lee, Max E. and Haiman, Zoltán and Pandey, Shivam and Genel, Shy}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{The effect of intrinsic alignments on weak-lensing statistics in hydrodynamical simulations}}, doi = {10.3847/1538-4357/ae1ca7}, volume = {996}, year = {2025}, } @article{18069, abstract = {We present results from the JWST First Reionization Epoch Spectroscopically Complete Observations survey on the star-forming sequence (SFS) of galaxies at 1.0 < z < 1.7, around the peak of the cosmic star formation history. Star formation rates (SFRs) are measured from the redshifted, relatively dust-insensitive Paschen-α emission line, and stellar mass measurements include the F444W (4.4 μm; rest-frame H) band. We find SFRs of galaxies with log(M*/M⊙) > 9.5 that are lower than found in many earlier studies by up to 0.6 dex, but in good agreement with recent results obtained with the Prospector fitting framework. The difference (log(SFR(Paα)-SFR(Prospector)) is −0.09 ± 0.04 dex at 1010−11M⊙. We also measure the empirical relation between Paschen-α luminosity and rest-frame H-band magnitude and find that the scatter is only 0.04 dex lower than that of the SFR–M* relation and is much lower than the systematic differences among relations in the literature due to various methods of converting observed measurements to physical properties. We additionally identify examples of sources—that, with standard cutoffs via the UVJ diagram, would be deemed quiescent—with significant (log(sSFR)> −11 yr−1), typically extended, Paschen-α emission. Our results may be indicative of the potential unification of methods used to derive the SFS with careful selection of star-forming galaxies and independent SFR and stellar mass indicators.}, author = {Neufeld, Chloe and Van Dokkum, Pieter and Asali, Yasmeen and Covelo-Paz, Alba and Leja, Joel and Lin, Jamie and Matthee, Jorryt J and Oesch, Pascal A. and Reddy, Naveen A. and Shivaei, Irene and Whitaker, Katherine E. and Wuyts, Stijn and Brammer, Gabriel and Marchesini, Danilo and Maseda, Michael V. and Naidu, Rohan P. and Nelson, Erica J. and Velichko, Anna and Weibel, Andrea and Xiao, Mengyuan}, issn = {1538-4357}, journal = {Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{FRESCO: The Paschen-α star-forming sequence at cosmic noon}}, doi = {10.3847/1538-4357/ad6158}, volume = {972}, year = {2024}, } @article{18494, abstract = {We expect luminous (M 1450 ≲ −26.5) high-redshift quasars to trace the highest-density peaks in the early Universe. Here, we present observations of four z ≳ 6 quasar fields using JWST/NIRCam in the imaging and wide-field slitless spectroscopy mode and report a wide range in the number of detected [O iii]-emitting galaxies in the quasars’ environments, ranging between a density enhancement of δ ≈ 65 within a 2 cMpc radius—one of the largest protoclusters during the Epoch of Reionization discovered to date—to a density contrast consistent with zero, indicating the presence of a UV-luminous quasar in a region comparable to the average density of the Universe. By measuring the two-point cross-correlation function of quasars and their surrounding galaxies, as well as the galaxy autocorrelation function, we infer a correlation length of quasars at 〈z〉 = 6.25 of r 0 QQ = 22.0 − 2.9 + 3.0 cMpc h − 1 , while we obtain a correlation length of the [O iii]-emitting galaxies of r 0 GG = 4.1 ± 0.3 cMpc h − 1 . By comparing the correlation functions to dark-matter-only simulations we estimate the minimum mass of the quasars’ host dark matter halos to be log 10 ( M halo , min / M ⊙ ) = 12.43 − 0.15 + 0.13 (and log 10 ( M halo , min [ OIII ] / M ⊙ ) = 10.56 − 0.03 + 0.05 for the [O iii] emitters), indicating that (a) luminous quasars do not necessarily reside within the most overdense regions in the early Universe, and that (b) the UV-luminous duty cycle of quasar activity at these redshifts is f duty ≪ 1. Such short quasar activity timescales challenge our understanding of early supermassive black hole growth and provide evidence for highly dust-obscured growth phases or episodic, radiatively inefficient accretion rates.}, author = {Eilers, Anna Christina and Mackenzie, Ruari and Pizzati, Elia and Matthee, Jorryt J and Hennawi, Joseph F. and Zhang, Haowen and Bordoloi, Rongmon and Kashino, Daichi and Lilly, Simon J. and Naidu, Rohan P. and Simcoe, Robert A. and Yue, Minghao and Frenk, Carlos S. and Helly, John C. and Schaller, Matthieu and Schaye, Joop}, issn = {1538-4357}, journal = {Astrophysical Journal}, number = {2}, publisher = {IOP Publishing}, title = {{EIGER. VI. The correlation function, host halo mass, and duty cycle of luminous quasars at z ≳ 6}}, doi = {10.3847/1538-4357/ad778b}, volume = {974}, year = {2024}, } @article{18524, abstract = {Recent works have constrained the binary fraction of evolved populations of massive stars in local galaxies such as red supergiants and Wolf–Rayet stars, but the binary fraction of yellow supergiants (YSGs) in the Hertzsprung gap remains unconstrained. Binary evolution theory predicts that the Hertzsprung gap is home to multiple populations of binary systems with varied evolutionary histories. In this paper, we develop a method to distinguish single YSGs from YSG plus O- or B-type main-sequence binaries using optical and ultraviolet photometry, and then apply this method to identify candidate YSG binaries in the Magellanic Clouds. After constructing a set of combined stellar atmosphere models, we find that optical photometry is, given typical measurement and reddening uncertainties, sufficient to discern single YSGs from YSG+OB binaries if the OB-star is at least ∼5M⊙ for Teff,YSG ∼ 4000 K, but requires a ∼20M⊙ OB star for YSGs up to Teff,YSG ∼ 9000 K. For these hotter YSG temperatures, ultraviolet photometry allows binaries with OB companions as small as ∼7M⊙ to be identified. We use color–color spaces developed from these models to search for evidence of excess blue or ultraviolet light in a set of ∼1000 YSG candidates in the Magellanic Clouds. We identify hundreds of candidate YSG binary systems and report a preliminary fraction of YSGs that show a blue/UV color excess of 20%–60%. Spectroscopic follow-up is now required to confirm the true nature of this population.}, author = {O’Grady, Anna J.G. and Drout, Maria R. and Neugent, Kathryn F. and Ludwig, Bethany and Götberg, Ylva Louise Linsdotter and Gaensler, B. M.}, issn = {1538-4357}, journal = {Astrophysical Journal}, publisher = {IOP Publishing}, title = {{Binary yellow supergiants in the Magellanic Clouds. I. Photometric candidate identification}}, doi = {10.3847/1538-4357/ad778a}, volume = {975}, year = {2024}, } @article{18584, abstract = {In this paper, we describe the "Medium Bands, Mega Science" JWST Cycle 2 survey (JWST-GO-4111) and demonstrate the power of these data to reveal both the spatially integrated and spatially resolved properties of galaxies from the local Universe to the era of cosmic dawn. Executed in 2023 November, MegaScience obtained ∼30 arcmin2 of deep multiband NIRCam imaging centered on the z ∼ 0.3 A2744 cluster, including 11 medium-band filters and the two shortest-wavelength broadband filters, F070W and F090W. Together, MegaScience and the UNCOVER Cycle 1 treasury program provide a complete set of deep (∼28–30 magAB) images in all NIRCam medium- and broadband filters. This unique data set allows us to precisely constrain photometric redshifts, map stellar populations and dust attenuation for large samples of distant galaxies, and examine the connection between galaxy structures and formation histories. MegaScience also includes ∼17 arcmin2 of NIRISS parallel imaging in two broadband and four medium-band filters from 0.9 to 4.8 μm, expanding the footprint where robust spectral energy distribution (SED) fitting is possible. We provide example SEDs and multiband cutouts at a variety of redshifts, and use a catalog of JWST spectroscopic redshifts to show that MegaScience improves both the scatter and catastrophic outlier rate of photometric redshifts by factors of 2–3. Additionally, we demonstrate the spatially resolved science enabled by MegaScience by presenting maps of the [O iii] line emission and continuum emission in three spectroscopically confirmed z > 6 galaxies. We show that line emission in reionization-era galaxies can be clumpy, extended, and spatially offset from continuum emission, implying that galaxy assembly histories are complex even at these early epochs. We publicly release fully reduced mosaics and photometric catalogs for both the NIRCam primary and NIRISS parallel fields (jwst-uncover.github.io/megascience).}, author = {Suess, Katherine A. and Weaver, John R. and Price, Sedona H. and Pan, Richard and Wang, Bingjie and Bezanson, Rachel and Brammer, Gabriel and Cutler, Sam E. and Labbé, Ivo and Leja, Joel and Williams, Christina C. and Whitaker, Katherine E. and Atek, Hakim and Dayal, Pratika and De Graaff, Anna and Feldmann, Robert and Franx, Marijn and Fudamoto, Yoshinobu and Fujimoto, Seiji and Furtak, Lukas J. and Goulding, Andy D. and Greene, Jenny E. and Khullar, Gourav and Kokorev, Vasily and Kriek, Mariska and Lorenz, Brian and Marchesini, Danilo and Maseda, Michael V. and Matthee, Jorryt J and Miller, Tim B. and Mitsuhashi, Ikki and Mowla, Lamiya A. and Muzzin, Adam and Naidu, Rohan P. and Nanayakkara, Themiya and Nelson, Erica J. and Oesch, Pascal A. and Setton, David J. and Shipley, Heath and Smit, Renske and Spilker, Justin S. and Van Dokkum, Pieter and Zitrin, Adi}, issn = {1538-4357}, journal = {Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{Medium bands, mega science: A JWST/NIRCam medium-band imaging survey of A2744}}, doi = {10.3847/1538-4357/ad75fe}, volume = {976}, year = {2024}, }