Sazuna/UAT_keywords huggingface dataset:
Physics-informed Priors Improve Gravitational-wave Constraints on Neutron-star Matter. Gravitational-wave astronomy shows great promise in determining nuclear physics in a regime not accessible to terrestrial experiments. We introduce physics-informed priors constrained by nuclear theory and perturbative quantum chromodynamics calculations, as well as astrophysical measurements of neutron-star masses and radii. When these priors are used in gravitational-wave astrophysical inference, we show a significant improvement on nuclear-matter constraints. Applying these to the first observed gravitational-wave binary neutron-star merger GW170817, the constraints on the radius of a 1.4 M⊙ neutron star improve from  R1.4=12.54−1.54+1.05  to  R1.4=12.11−1.11+0.91km  and those on the tidal deformability from  Λ∼1.186&lt;720  to  Λ∼1.186=384−158+306  (90% confidence intervals and 95% upper limit) at the source-frame chirp mass  M=1.186M⊙  when compared to the LIGO─Virgo─KAGRA analysis with uniform priors. We also show that these priors can be used to perform model selection between binary neutron star and neutron star─black hole mergers; in the case of GW190425, the results provide only marginal evidence with a Bayes factor  BF=1.33  in favor of the binary neutron star merger hypothesis. Given their ability to improve the astrophysical inference of binary mergers involving neutron stars, we advocate for these physics-informed priors to be used as standard in the literature and provide open-source code for reproducibility and adaptation of the method.

Keywords: Neutron stars, Gravitational wave astronomy, Nuclear physics
Is Earendel a Star Cluster?: Metal-poor Globular Cluster Progenitors at z ∼ 6. The strongly lensed z ∼ 6 Sunrise galaxy offers an incredible opportunity to investigate star formation in the early Universe on parsec or smaller scales. The highly magnified object Earendel within the Sunrise was previously identified as a candidate star or binary owing to size constraints placed by the lensing magnification; however, recent works have suggested that this constraint may be relaxed to even the size of star clusters. Here we explore the hypothesis that Earendel may actually be a star cluster, and we simultaneously evaluate other star clusters within the host galaxy. Leveraging deep, archival James Webb Space Telescope NIRSpec PRISM spectroscopy, we determine a spectroscopic redshift for the Sunrise galaxy z = 5.926 ± 0.013, and we fit simple stellar population (SSP) models from three premier libraries to evaluate the physical parameters of Earendel and another distinct star cluster in the Sunrise dubbed "1b." We find the rest-UV through optical continuum of Earendel to be well described by an SSP, nearly equivalently to 1b, which is confidently a star cluster. We infer that they have intermediate ages tage ∼ 30–150 Myr, are metal-poor (Z⋆ ≲ 0.1 Z⊙), and are consistent with the formation age–metallicity trend seen in local globular clusters. Such intermediate-age clusters are seldom probed spectroscopically in the high-redshift Universe, and we explore the extent to which these clusters can be characterized via the spectroscopic continuum.

Keywords: Globular star clusters, Strong gravitational lensing, Young star clusters
A Torus Remnant Revealed by the Infrared Echo of Tidal Disruption Event AT 2019qiz: Implications for the Missing Energy and Quasiperiodic Eruption Formation. AT 2019qiz is the first standard optical tidal disruption event (TDE) with detection of X-ray quasiperiodic eruptions (QPEs), providing strong evidence for TDE–QPE association. Moreover, it belongs to the rare subset of optical TDEs with prominent infrared (IR) echoes revealed by the multiepoch photometry from the Wide-field Infrared Survey Explorer (WISE). The IR light curve shows an early bump, followed by a steady rise until the second-to-last epoch, after which it appears to enter a plateau phase. The dust temperature decreased until the fourth epoch and remains approximately constant for the subsequent five epochs. We have fitted the last five epochs using a convex dust ring model, resulting in an inner radius &gt;1.2 pc. Such a large radius greatly exceeds the inner radius of the active galactic nucleus (AGN) torus for a 106 M⊙ black hole and thus could be a torus remnant with the inner part having vanished, further supporting the unified scenario of recently faded AGNs, TDEs, and QPEs. Consequently, a connection between QPEs and IR-bright TDEs is naturally expected. Moreover, the echo requires at least a peak bolometric luminosity of (6.6, 9.5, 1.0) × 1044 erg s‑1 assuming silicate, silicon carbide, and graphite dust grains, respectively, all of which are significantly higher than the peak optical blackbody luminosity. It adds to the accumulating evidence that the missing energy of TDEs may lie in the unobservable extreme UV. This work highlights the unique value of IR echoes in the study of TDEs and QPEs and a promising prospect in the era of the Near-Earth Object Surveyor, the successor to WISE.

Keywords: Infrared astronomy, Tidal disruption, Time domain astronomy, High energy astrophysics
A New Brown Dwarf Orbiting an M Star and an Investigation of the Eccentricity Distribution of Transiting Long-period Brown Dwarfs. The orbital eccentricities of brown dwarfs encode valuable information on their formation and evolution history, providing insights into whether they resemble giant planets or stellar binaries. Here, we report the discovery of TOI-5575 b, a long-period, massive brown dwarf orbiting a low-mass M5V star (0.21 ± 0.02 M⊙) delivered by the TESS mission. The companion has a mass and radius of 72.4 ± 4.1 MJ and 0.84 ± 0.07 RJ on a 32 day moderately eccentric orbit (e = 0.187 ± 0.002), making it the third-highest mass ratio transiting brown dwarf system known to date. Building on this discovery, we investigate the eccentricity distributions of a sample of transiting long-period (10 days ≤ P ≲ 1000 days, ∼0.1─1.5 au) giant planets, brown dwarfs, and low-mass stars. We find that brown dwarfs exhibit an eccentricity behavior nearly identical to that of giant planets: a preference for circular orbits with a long tail toward high eccentricities. Such a trend contrasts sharply with direct imaging findings, where cold (5─100 au) brown dwarfs and giant planets display distinct eccentricity distributions. Our results suggest that transiting long-period brown dwarfs and giant planets probably (1) form in different routes at exterior orbits but undergo analogous dynamical evolution processes and migrate inward or (2) both contain two subgroups, one with widely spread eccentricities while the other has circular orbits, that jointly sculpt the eccentricity distributions. The low-mass star systems appear to be a distinctive population, showing a peak eccentricity at about 0.3, akin to more massive stellar binaries.

Keywords: Brown dwarfs, Binary stars, Astrostatistics, Low mass stars, Radial velocity, Transit photometry, Extrasolar gaseous giant planets, Eccentricity
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). I. Program Overview and Summary of First Results. We present the Atacama Large Millimeter/submillimeter Array Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO), a large program of the ALMA. AGE-PRO aims to systematically trace the evolution of gas disk mass and size throughout the lifetime of protoplanetary disks. It uses a carefully selected sample of 30 disks around M3-K6 stars in three nearby star-forming regions: Ophiuchus (0.5─1 Myr), Lupus (1─3 Myr), and Upper Sco (2─6 Myr). Assuming the three regions had similar initial conditions and evolutionary paths, we find the median gas disk mass appears to decrease with age. Ophiuchus disks have the highest median gas mass (6 MJup), while the Lupus and Upper Sco disks have significantly lower median masses (0.68 and 0.44 MJup, respectively). Notably, the gas and dust disk masses appear to evolve on different timescales. This is evidenced by the median gas-to-dust mass ratio, which decreases from 122 in the youngest disks (&lt;1 Myr) to 46 in Lupus disks, and then increases to 120 in the Upper Sco disks. The median gas disk sizes range between 74 and 110 au, suggesting that typical gas disks are much smaller than those of well-studied, massive disks. Population synthesis models suggest that magnetohydrodynamic wind-driven accretion can reproduce median disk properties across all three regions, when assuming compact disks with a declining magnetic field over time. In contrast, turbulent-driven models overestimate gas masses of &gt;1 Myr disks by an order of magnitude. Here, we discuss the program's motivation, survey design, sample selection, observation and data calibration processes, and highlight the initial results.

Keywords: Protoplanetary disks, Planet formation
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). II. Dust and Gas Disk Properties in the Ophiuchus Star-forming Region. The ALMA survey of Gas Evolution in PROtoplanetary disks (AGE-PRO) Large Program aims to trace the evolution of gas disk mass and size throughout the lifetime of protoplanetary disks by using the Atacama Large Millimeter/submillimeter Array (ALMA). This paper presents Band-6 ALMA observations of 10 embedded (Class I and Flat Spectrum) sources in the Ophiuchus molecular cloud, with spectral types ranging from M3 to K6 stars, which serve as the evolutionary starting point in the AGE-PRO sample. While we find four nearly edge-on disks (≥70°), and three highly inclined disks (≥60°) in our sample, we show that, as a population, embedded disks in Ophiuchus are not significantly contaminated by more-evolved, but highly inclined sources. We derived dust disk masses from the Band-6 continuum and estimated gas disk masses from the C18O J = 2−1 and C17O J = 2−1 lines. The mass estimates from the C17O line are slightly higher, suggesting C18O emission might be partially optically thick. While the 12CO and 13CO lines are severely contaminated by extended emission and self-absorption, the C18O and C17O lines are allowed to trace the radial extent of the gaseous disks. From these measurements, we found that the C18O J = 2−1 and C17O J = 2−1 fluxes correlate well with each other and with the continuum fluxes. Furthermore, the C18O and C17O lines present a larger radial extension than disk dust sizes by factors ranging from ∼1.5 to ∼2.5, as is found for Class II disks using the radial extension of the 12CO. In addition, we have detected outflows in three disks from 12CO observations.

Keywords: Submillimeter astronomy, Protoplanetary disks, Planet formation, Circumstellar disks
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). III. Dust and Gas Disk Properties in the Lupus Star-forming Region. We present Band 6 and Band 7 observations of 10 Lupus disks around M3-K6 stars from the Atacama Large Millimeter/submillimeter Array survey of Gas Evolution in PROtoplanetary disks (AGE-PRO) Large Program. In addition to continuum emission in both bands, our Band 6 setup covers the 12CO, 13CO, and C18O J = 2─1 lines, while our Band 7 setup covers the N2H+ J = 3─2 line. All of our sources are detected in 12CO and 13CO; seven out of ten are detected in C18O; and three are detected in N2H+. We find strong correlations between the CO isotopologue line fluxes and the continuum flux densities. With the exception of one disk, we also identify a strong correlation between the C18O J = 2─1 and N2H+ J = 3─2 fluxes, indicating similar CO abundances across this sample. For the two sources with well-resolved continuum and 12CO J = 2─1 images, we find that their gas-to-dust size ratio is consistent with the median value of ∼2 inferred from a larger sample of Lupus disks. We derive dust disk masses from continuum flux densities. We estimate gas disk masses by comparing C18O J = 2─1 line fluxes with those predicted by the limited grid of self-consistent disk models of M. Ruaud et al. A comparison of these mass estimates with those derived by L. Trapman et al., using a combination of CO isotopologue and N2H+ line emission, shows that the masses are consistent with each other. Some discrepancies appear for small and faint disks, but they are still within the uncertainties. Both methods find gas disk masses increase with dust disk masses, and gas-to-dust mass ratios are between 10 and 100 in the AGE-PRO Lupus sample.

Keywords: Millimeter astronomy, Astrochemistry, Protoplanetary disks, Submillimeter astronomy, Planet formation
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). IV. Dust and Gas Disk Properties in the Upper Scorpius Star-forming Region. The Atacama Large Millimeter/submillimeter Array (ALMA) large program AGE-PRO explores protoplanetary disk evolution by studying gas and dust across various ages. This work focuses on 10 evolved disks in Upper Scorpius, observed in dust continuum emission, CO and its isotopologues, and N2H+ with ALMA Bands 6 and 7. Disk radii, from the radial location enclosing 68% of the flux, are comparable to those in the younger Lupus region for both gas and dust tracers. However, solid masses are about an order of magnitude below those in Lupus and Ophiuchus, while the dust spectral index suggests some level of dust evolution. These empirical findings align with a combination of radial drift, dust trapping, and grain growth into larger bodies. A moderate correlation between CO and continuum fluxes suggests a link between gas and dust content, through the increased scatter compared to younger regions, possibly due to age variations, gas-to-dust ratio differences, or CO depletion. Additionally, the correlation between C18O and N2H+ fluxes observed in Lupus persists in Upper Scorpius, indicating a relatively stable CO gas abundance over the Class II stage of disk evolution. In conclusion, the AGE-PRO survey of Upper Scorpius disks reveals intriguing trends in disk evolution. The findings point toward potential gas evolution and the presence of dust traps in these older disks. Future high-resolution observations are needed to confirm these possibilities and further refine our understanding of disk evolution and planet formation in older environments.

Keywords: Submillimeter astronomy, Protoplanetary disks, Astrochemistry
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). V. Protoplanetary Gas Disk Masses. The evolution of the gas mass of planet-forming disks around young stars is crucial for our understanding of planet formation, yet it has proven hard to constrain observationally, due both to the difficulties of measuring gas masses and the lack of a homogeneous sample. Here we present a large grid of thermochemical models that we use to measure protoplanetary gas disk masses of AGE-PRO, the Atacama Large Millimeter/submillimeter Array survey of Gas Evolution in PROtoplanetary disks. AGE-PRO covers a sample of 30 disks around similar spectral type (M3-K6) stars with ages between 0.1 and 10 Myr. Our approach is to simultaneously fit observations of CO isotopologues and N2H+, a complementary molecule produced when CO freezes out. We find that the median gas mass of the three regions decreases over time, from  7.0‑2.6+4.4×10‑3M⊙  in Ophiuchus (≲1 Myr) to  9.4‑3.4+5.4×10‑4M⊙  for Lupus (∼1–3 Myr) and  6.8‑2.8+5.1×10‑4M⊙  for Upper Sco (∼2–6 Myr), with ∼1 dex scatter in gas mass in each region. We note that the gas mass distributions for Lupus and Upper Sco look very similar, which could be due to survivorship bias for the latter. The median bulk CO abundance in the CO emitting layer is found to be a factor ∼10 lower than the interstellar medium value but does not significantly change between Lupus and Upper Sco. From Lupus to Upper Sco, the median gas-to-dust mass ratio increases by a factor ∼3 from ∼40 to ∼120, suggesting efficient inward pebble drift and/or the formation of planetesimals.

Keywords: Protoplanetary disks, Radiative transfer, Astrochemistry
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). VI. Comparison of Dust Evolution Models to AGE-PRO Observations. The potential for planet formation of a circumstellar disk depends on the dust and gas reservoirs, which evolve as a function of the disk age. The Atacama Large Millimeter/submillimeter Array AGE-PRO Large Program has measured several disk properties across three star-forming regions of different ages, and in this study, we compare the observational results to dust evolution simulations. Using DustPy for the dust evolution, and RADMC-3D for the radiative transfer, we ran a large grid of models spanning stellar masses of 0.25, 0.50, 0.75, and 1.0 M⊙, with different initial conditions, including: disk sizes, disk gas masses, and dust-to-gas ratio, and viscosity. Our models are performed assuming smooth, weakly, or strongly substructured disks, aiming to investigate if any observational trend can favor or exclude the presence of dust traps. The observed gas masses in the disks of the AGE-PRO sample are not reproducible with our models, which only consider viscous evolution with constant α, suggesting that additional physical mechanisms play a role in the evolution of the gas mass of disks. When comparing the dust continuum emission fluxes and sizes at 1.3 mm, we find that most of the disks in the AGE-PRO sample are consistent with simulations that have either weak or strong dust traps. The evolution of spectral index in the AGE-PRO sample is also suggestive of an unresolved population of dust traps. Future observations at high angular resolution are still needed to test several hypotheses that result from comparing the observations to our simulations, including that more massive disks in gas mass have the potential to form dust traps at larger disk radii.

Keywords: Stellar accretion disks, Hydrodynamical simulations, Protoplanetary disks
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). VII. Testing Accretion Mechanisms from Disk Population Synthesis. The architecture of planetary systems depends on the evolution of the disks in which they form. In this work, we develop a population synthesis approach to interpret the Atacama Large Millimeter/submillimeter Array survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO) measurements of disk gas mass and size considering two scenarios: turbulence-driven evolution with photoevaporative winds and MHD wind-driven evolution. A systematic method is proposed to constrain the distribution of disk parameters from the disk fractions, accretion rates, disk gas masses, and CO gas sizes. We find that turbulence-driven accretion with initially compact disks (R0 ≃ 5–20 au), low mass-loss rates, and relatively long viscous timescales (tν,0 ≃ 0.4–3 Myr or αSS ≃ 2–4 × 10‑4) can reproduce the disk fractions and gas sizes. However, the distribution of apparent disk lifetimes defined as the  MD/Ṁ*  ratio is severely overestimated by turbulence-driven models. On the other hand, MHD wind-driven accretion can reproduce the bulk properties of disk populations from Ophiuchus to Upper Scorpius assuming compact disks with an initial magnetization of about β ≃ 105 (αDW ≃ 0.5–1 × 10‑3) and a magnetic field that declines with time. More studies are needed to confirm the low masses found by AGE-PRO, notably for compact disks that question turbulence-driven accretion. The constrained synthetic disk populations can now be used for realistic planet population models to interpret the properties of planetary systems on a statistical basis.

Keywords: Exoplanet formation, Protoplanetary disks
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). VIII. The Impact of External Photoevaporation on Disk Masses and Radii in Upper Scorpius. Protoplanetary disk evolution can be deeply influenced by the UV radiation emitted by neighboring massive stars (mainly of spectral types O and B). We show that the process of external photoevaporation, which causes an outside-in depletion of disk material due to environmental UV radiation, can lead to a significant decrease in disk size, disk mass, and lifetime even at moderate irradiation levels (1–10 G0). In this work, we investigate the role of external photoevaporation in shaping the masses and sizes of the 10 AGE-PRO disks in the Upper Scorpius (Upper Sco) region, which we estimate to be subject to far-ultraviolet (FUV) fluxes ranging between ∼2 and ∼12 G0, on average. We compare the disk masses and sizes resulting from 1D numerical viscous evolution simulations, in which the effect of external photoevaporation is included, to the values retrieved from the AGE-PRO observations. While the pure viscous framework fails in adequately explaining the observed disk properties in Upper Sco, with the inclusion of external photoevaporation, we can successfully reproduce gas disk sizes for seven out of 10 sources within a factor &lt;2, when the initial disk mass is 1%–10% of the stellar mass. We emphasize the importance of accounting for the environmental irradiation when comparing star-forming regions of different ages, even when moderate FUV irradiation fields are experienced, as in the case of Upper Sco.

Keywords: Circumstellar gas, Protoplanetary disks, Circumstellar disks
The ALMA Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO). X. Dust Substructures, Disk Geometries, and Dust-disk Radii. We perform visibility fitting to the dust continuum Band 6 1.3 mm data of the 30 protoplanetary disks in the Atacama Large Millimeter/submillimeter Array Survey of Gas Evolution of PROtoplanetary Disks (AGE-PRO) Large Program. We obtain disk geometries, dust-disk radii, and azimuthally symmetric radial profiles of the intensity of the dust continuum emission. We examine the presence of continuum substructures in the AGE-PRO sample by using these radial profiles and their residuals. We detect substructures in 15 out of 30 disks. We report five disks with large (&gt;15 au) inner dust cavities. The Ophiuchus Class I disks show dust-disk substructures in ∼80% of the resolved sources. This evidences the early formation of substructures in protoplanetary disks. A spiral is identified in IRS 63, hinting to gravitational instability in this massive disk. We compare our dust-disk brightness radial profiles with gas-disk brightness radial profiles and discuss colocal substructures in both tracers. In addition, we discuss the evolution of dust-disk radii and substructures across Ophiuchus, Lupus, and Upper Scorpius. We find that disks in Lupus and Upper Scorpius with large inner dust cavities have typical gas-disk masses, suggesting an abundance of dust cavities in these regions. The prevalence of pressure dust traps at later ages is supported by a potential trend with time with more disks with large inner dust cavities (or transition disks) in Upper Scorpius and the absence of evolution of dust-disk sizes with time in the AGE-PRO sample. We propose this is caused by an evolutionary sequence with a high fraction of protoplanetary disks with inner protoplanets carving dust cavities.

Keywords: Gas-to-dust ratio, Planetary-disk interactions, Exoplanets, Star forming regions, Star formation, Protoplanetary disks, Dust continuum emission, Circumstellar disks, Stellar accretion disks, Circumstellar dust, Radio interferometry, Planet formation