Sazuna/UAT_keywords huggingface dataset:
Evidence for a Sharp CO Snow Line Transition in a Protoplanetary Disk and Implications for Millimeter-wave Observations of CO Isotopologues. Observations of CO isotopologue emission from protoplanetary disks at millimeter wavelengths are a powerful tool for probing the CO snow line, an important marker for disk chemistry, and also for estimating total disk gas mass, a key quantity for planet formation. We use simple models to demonstrate that the vertical thickness of an isothermal layer around the disk midplane has important effects on the CO column density radial profile, with a thick layer producing a sharp CO snow line transition. We simulate next-generation Very Large Array (ngVLA) and Atacama Large Millimeter/submillimeter Array (ALMA) images to show that this sharp change in the CO column density can be detected in the derivative of the radial profile of emission from optically thin CO isotopologue lines. We apply this method to archival ALMA observations of the disk around the Herbig Ae star HD 163296 in the C17O and C18O J = 1–0 and J = 2–1 lines to identify a sharp CO snow line transition near ∼80 au (0.″8 at 101 pc), and show the CO column density decreases by more than a factor of 20. This finding is consistent with previous inferences from the steep rise of N2H+ emission, which marks the location where CO depletes. We also demonstrate that the disk's thermal structure introduces significant systematic uncertainty to estimates of total disk gas mass derived from these lines. The substantial improvement in sensitivity envisioned for the ngVLA over ALMA for observations of ground-state lines of CO isotopologues has the potential to extend this approach to a much larger population of disks.

Keywords: Millimeter astronomy, Protoplanetary disks, Planet formation
Planet Mass Function around M Stars at 1–10 au: A Plethora of Sub-Earth Mass Objects. Small planets (≲1 M ⊕) at intermediate orbital distances (∼1 au) represent an uncharted territory in exoplanetary science. The upcoming microlensing survey by the Nancy Grace Roman Space Telescope will be sensitive to objects as light as Ganymede and unveil the small planet population at 1–10 au. Instrumental sensitivity to such planets is low, and the number of objects we will discover is strongly dependent on the underlying planet mass function. In this work, we provide a physically motivated planet mass function by combining the efficiency of planet formation by pebble accretion with the observed disk mass function. Because the disk mass function for M dwarfs (0.4–0.6 M ⊙) is bottom heavy, the initial planet mass function is also expected to be bottom heavy, skewing toward Ganymede and Mars mass objects, more so for heavier initial planetary seeds. We follow the subsequent dynamical evolution of planetary systems over ∼100 Myr varying the initial eccentricity and orbital spacing. For initial planet separations of ≥3 local disk scale heights, we find that Ganymede and Mars mass planets do not grow significantly by mergers. However, Earth-like planets undergo vigorous merging and turn into super-Earths, potentially creating a gap in the planet mass function at ∼1 M ⊕. Our results demonstrate that the slope of the mass function and the location of the potential gap in the mass function can probe the initial architecture of multiplanet systems. We close by discussing implications on the expected difference between bound and free-floating planet mass functions.

Keywords: Exoplanet astronomy, Gravitational microlensing exoplanet detection, Exoplanet dynamics, Exoplanet formation
Misaligned Gas Acquisition as a Formation Pathway of S0 Galaxies. We analyze a sample of 753 S0 galaxies from the MPL-10 of Mapping Nearby Galaxies at Apache Point Observatory survey and investigate the gas–star kinematic misalignment and merger remnant fraction in galaxies with different morphological types. The misalignment fraction in S0s is the highest among all the morphological types for both young (global D n 4000 &lt; 1.6, ∼15%) and old (global D n 4000 &gt; 1.6, ∼10%) galaxies. We compare the properties of misaligned S0s with other types of galaxies, finding the following: (i) misaligned S0s and misaligned spirals have higher bulge luminosity, higher bulge-to-total light ratio, and larger Sérsic index compared to spirals; (ii) the misaligned S0s have lower bulge luminosity M  r  and smaller bulge size than merger remnant S0s, while aligned S0s have the widest coverage for these parameter distributions, which are overlapped with both misaligned S0s and merger remnant S0s; (iii) misaligned S0s have lower stellar mass M * and more isolated environment than aligned S0s and merger remnant S0s; and (iv) the young misaligned S0s have positive D n 4000 radial gradient, while the aligned S0s and merger remnant S0s show negative D n 4000 radial gradient. Combining all these observational results, we suggest misaligned gas acquisition as another efficient formation pathway for S0 galaxies. The redistribution of gas angular momentum during gas–gas collision between accreted and preexisting gas leads to gas inflow and the growth of the bulge component, while the lack of cold gas at the outskirts leads to fading of spiral arms.

Keywords: Lenticular galaxies, Galaxy formation, Galaxy kinematics
Simulations of the Collision between a Debris Stream and an Outer Dusty Torus: A Possible Channel for Forming a Fast-rise and Long-delay Radio Outburst in Tidal Disruption Events. A geometrically thick dusty torus structure is believed to exist in the nuclear regions of galaxies (especially in active galactic nuclei). The debris stream from a tidal disruption event (TDE) will possibly collide with the dusty torus and produce a transient flare. We perform three-dimensional hydrodynamic simulations to model the dynamical evolution of the interaction between unbound debris and a dusty torus. During the continuous interaction, shocked material will be spilled out from the interaction region and form an outflow. We calculate the temporal evolution of synchrotron emission by assuming that the shock accelerates a fraction of electrons in the outflow into a nonthermal distribution. We find that radio emission from the debris–torus collision generates a steep-rise and slow-decline radio light curve due to the sharp edge and dense gas of the dusty torus, where the radio outburst is delayed relative to the main optical/X-ray outburst by several years or even several tens of years. We apply our model to a TDE that happened in a narrow-line Seyfert I galaxy (PS16dtm), where both the radio spectrum and the light curve can be roughly reproduced. Future high-sensitivity, wide-field-of-view radio surveys have the opportunity to detect more such radio flares.

Keywords: Tidal disruption, Active galactic nuclei
Detection Rate of Galaxy Cluster-lensed Stellar Binary Black Hole Mergers by the Third-generation Gravitational-wave Detectors. Gravitational waves (GWs) from stellar binary black hole (sBBH) mergers can be strongly gravitational lensed by intervening galaxies/galaxy clusters. Only a few works have investigated cluster-lensed sBBH mergers by adopting oversimplified models, while galaxy-lensed ones have been intensively studied. In this paper, we estimate the detection rate of cluster-lensed sBBH mergers with third-generation GW detectors and its dependence on the lens models. We adopt detailed modeling of galaxy cluster lenses by using the mock clusters in the Synthetic Sky Catalog for Dark Energy Science with LSST (cosmoDC2) and/or approximations of the pseudo-Jaffe profile or an eccentric Navarro–Frenk–White dark matter halo plus a bright central galaxy with singular isothermal sphere profile. Considering that the formation of sBBH mergers is dominated by the evolution of the massive binary star (EMBS) channel, we find that the detection rate of cluster-lensed sBBHs is ∼5–84 yr‑1, depending on the adopted lens model and uncertainty in the merger rate density, which is about   yr‑1 if adopting relatively more realistic galaxy clusters with central main and member galaxies in the cosmoDC2 catalog, close to the estimated detection rate of sBBH mergers lensed by galaxies. In addition, we also consider the case in which the production of sBBH mergers is dominated by the dynamical interactions in dense stellar systems. We find that the detection rate of cluster-lensed sBBHs from the dynamical channel is about 1.5 times larger than that from the EMBS channel, and the redshift distribution of the former peaks at a higher redshift (∼3) compared with that from the latter (∼2).

Keywords: Gravitational wave astronomy, Gravitational lensing, Gravitational wave sources
COBIPULSE: A Systematic Search for Compact Binary Millisecond Pulsars. We report here the results obtained from a systematic optical photometric survey aimed at finding new compact binary millisecond pulsars (also known as "spiders"): the COmpact BInary PULsar SEarch. We acquired multiband optical images over 1 yr around 33 unidentified Fermi Large Area Telescope sources, selected as pulsar candidates based on their curved GeV spectra and steady γ-ray emission. We present the discovery of four optical variables coinciding with the Fermi sources 3FGL J0737.2‑3233, 3FGL J2117.6+3725 (two systems in this field), and 3FGL J2221.6+6507, which we propose as new candidate spider systems. Indeed, they all show optical flux modulation consistent with orbital periods of 0.3548(5), 0.25328(6), 0.441961(2), and 0.165(4) days, respectively, with amplitudes ≳0.3 mag and colors compatible with companion star temperatures of 5000–6000 K. These properties are consistent with the "redback" subclass of spider pulsars. If confirmed as a millisecond pulsar, 3FGL J0737.2‑3233 will be the closest known spider to Earth ( , from Gaia-DR3 parallax). We searched and did not find any X-ray sources matching our four candidates, placing 3σ upper limits of ∼1031–1032 erg s‑1 (0.3–10 keV) on their soft X-ray luminosities. We also present and discuss other multiwavelength information on our spider candidates, from infrared to X-rays.

Keywords: Close binary stars, Variable stars, High energy astrophysics, Millisecond pulsars
On the Stellar Disk Vertical Scale Height of Edge-on Galaxies from S<SUP>4</SUP>G. Disk galaxies viewed as thin planar structures resulting from the conservation of angular momentum of an initially rotating pregalactic cloud allow merely a first-order model of galaxy formation, but the presence of vertically extended structures has allowed us to gather a deeper understanding of the richness in astrophysical processes (e.g., minor mergers, secular evolution) that ultimately results in the observed diversity in disk galaxies and their vertical extensions. We measure the stellar disk scale height of 46 edge-on spiral galaxies from the Spitzer Survey of Stellar Structure in Galaxies (S4G) project. This paper aims to investigate the radial variation of the stellar disk vertical scale height and the existence of the so-called thick disk component in our sample. The measurements were made using one-, two-, and three-dimensional profile fitting techniques using simple models. We found that two-thirds of our sample show the presence of a thick disk, suggesting that these galaxies have been accreting gaseous material from their surroundings. We found an average thick-to-thin disk scale height ratio of 2.65, which is in good agreement with previous studies. Our findings also support the disk flaring model, which suggests that the vertical scale height increases with radius. We further found good correlations between the scale height h  z  and the scale length and between h  z  and the optical de Vaucouleurs radius R 25.

Keywords: Galaxy photometry, Spiral galaxies
Exploring Field-evolution and Dynamical-capture Coalescing Binary Black Holes in GWTC-3. We investigate formation channels for merging binary black holes (BBHs) in GWTC-3, with a dedicated semiparametric population model. The model first describes or excludes a high-spin (with magnitudes of ∼0.7) and high-mass (ranging in ∼20–80M ⊙) subpopulation, which was identified by previous works and can be interpreted as hierarchical mergers. We find that the rest of BBH population can be categorized into two subpopulations with different mass and mass-ratio distributions, as indicated by a Bayes factor of  . One subpopulation, characterized by nearly aligned spins and consistent with isolated field formation, likely dominates the 10-solar-mass peak in the primary-mass function. The other subpopulation, with isotropic spins and consistent with the dynamical channels, shows a stronger preference for symmetric pairing, and mainly contributes to the 35-solar-mass peak in the primary-mass function. Note that the Bayes factor is not high enough with the currently available data, so that the case of a single population is still acceptable. Additionally, we compare the mass distributions between merging BBHs and black holes (BHs) in high-mass X-ray binaries (HMXBs). We find that the primary mass of the aligned subpopulation is slightly lighter than those of the HMXB BHs, while the isotropic subpopulation is consistent with the HMXB BHs, if the power-law index of its mass function is shifted by 2, as indicated by the dynamical formation channels. However, the spin magnitudes of both subpopulations are significantly smaller than those of the HMXB BHs.

Keywords: Late stellar evolution, Compact binary stars, Astrophysical black holes
The Second Case of a Major Merger Triggering a Starburst in a Green Pea Galaxy. We have used the Karl G. Jansky Very Large Array (VLA) to map H I 21 cm emission from the Green Pea galaxy GP J1148+2546 at z ≈ 0.0451, only the second measurement of the H I spatial distribution of a Green Pea. The VLA H I 21 cm image, the DECaLS optical image, and Sloan Digital Sky Survey spectroscopy show that GP J1148+2546 has two neighbors, the nearer of which is only ≈17.5 kpc away, and that the H I 21 cm emission extends in an inverted "C" shape around the Green Pea and its companions, with the highest H I column density between the two neighboring galaxies. The starburst in GP J1148+2546 is likely to have been triggered by the ongoing merger with its neighbors, although the velocity field and velocity dispersion images do not show clear merger signatures at the Green Pea location. The H I mass of the Green Pea and its immediate surroundings is (3.58 ± 0.37) × 109 M ⊙, a factor of ≈7.4 lower than the total H I mass of the system of three interacting galaxies, while the H I depletion timescale of GP J1148+2546 is ≈0.69 Gyr, much shorter than that of typical galaxies at z ≈ 0. We detect damped Lyα absorption and Lyα emission from the Green Pea in a Hubble Space Telescope Cosmic Origins Spectrograph spectrum, obtaining a high H I column density, ≈2.0 × 1021 cm‑2, and a low Lyα escape fraction, ≈0.8%, consistent with the relatively low value (≈5.4) of the ratio O32 ≡ [O III]λ5007 + λ4959/[O II]λ3727,3729.

Keywords: Starburst galaxies, Emission line galaxies, Galaxies, H I line emission
Accurately Estimating Redshifts from CSST Slitless Spectroscopic Survey Using Deep Learning. Chinese Space Station Telescope (CSST) has the capability to conduct a slitless spectroscopic survey simultaneously with a photometric survey. The spectroscopic survey will measure slitless spectra, potentially providing more accurate estimations of galaxy properties, particularly redshifts, compared to using broadband photometry. CSST relies on these accurate redshifts to use baryon acoustic oscillations (BAOs) and other probes to constrain the cosmological parameters. However, due to the low resolution and signal-to-noise ratio of slitless spectra, measurement of redshifts is significantly challenging. In this study, we employ a Bayesian neural network (BNN) to assess the accuracy of redshift estimations from slitless spectra anticipated to be observed by CSST. The simulation of slitless spectra is based on real observational data from the early data release of the Dark Energy Spectroscopic Instrument (DESI-EDR) and the 16th data release of the Baryon Oscillation Spectroscopic Survey (BOSS-DR16), combined with the 9th data release of the DESI Legacy Survey (DESI LS DR9). The BNN is constructed employing a transfer learning technique, by appending two Bayesian layers after a convolutional neural network, leveraging the features learned from the slitless spectra and corresponding redshifts. Our network can provide redshift estimates along with corresponding uncertainties, achieving an accuracy of σ NMAD = 0.00063, outlier percentage η = 0.92%, and weighted mean uncertainty  . These results successfully fulfill the requirement of σ NMAD &lt; 0.005 for BAO and other studies employing CSST slitless spectroscopic surveys.

Keywords: Cosmology, Galaxies
Strong Chemical Tagging in FIRE: Intra- and Intercluster Chemical Homogeneity in Open Clusters in Milky Way–like Galaxy Simulations. Open-star clusters are the essential building blocks of the Galactic disk; "strong chemical tagging"—the premise that all star clusters can be reconstructed given chemistry information alone—is a driving force behind many current and upcoming large Galactic spectroscopic surveys. In this work, we characterize the abundance patterns for nine elements (C, N, O, Ne, Mg, Si, S, Ca, and Fe) in open clusters (OCs) in three galaxies (m12i, m12f, and m12m) from the Latte suite of FIRE-2 simulations, to investigate the feasibility of strong chemical tagging in these simulations. We select young massive (≥104.6 M ⊙) OCs formed in the last ∼100 Myr and calculate the intra- and intercluster abundance scatter for these clusters. We compare these results with analogous calculations drawn from observations of OCs in the Milky Way. We find the intracluster scatter of the observations and simulations to be comparable. While the abundance scatter within each cluster is minimal (≲0.020 dex), the mean abundance patterns of different clusters are not unique. We also calculate the chemical difference in intra- and intercluster star pairs and find it, in general, to be so small that it is difficult to distinguish between stars drawn from the same OC or from different OCs. Despite tracing three distinct nucleosynthetic families (core-collapse supernovae, white dwarf supernovae, and stellar winds), we conclude that these elemental abundances do not provide enough discriminating information to use strong chemical tagging for reliable OC membership.

Keywords: Stellar abundances, OB associations, Galaxy disks, Open star clusters, Galactic abundances, Magnetohydrodynamical simulations
Comparison of the Chemical Compositions between the Bright and Faint Red Clumps for the Metal-poor and Metal-rich Populations in the Milky Way Bulge. We examined the double red clump (RC) observed in the Galactic bulge, interpreted as a difference in distance ("X-shaped bulge scenario") or in chemical composition ("multiple population scenario"). To verify chemical differences between the RC groups, we performed low-resolution spectroscopy for RC and red giant branch (RGB) stars using Gemini-South/GMOS in three fields of the bulge and collected diverse data from the literature. We divided our sample stars not only into bright RC (bRC) and faint RC (fRC) groups, but also into bluer ([Fe/H] &lt; −0.1) and redder ([Fe/H] &gt; −0.1) groups following recent u-band photometric studies. For the metal-poor stars, no statistically significant difference in the CN index was detected between the bright and faint RC groups for all observed fields. However, we found, from crossmatching with high-resolution spectroscopic data, a sign of Na enhancement in the "metal-poor and bright" RC group compared to the "metal-poor and faint" group at (l, b) = (−1°, −8.°5). When the contributions of the RGB stars on the RC regimes are taken into account, the Na abundance difference between genuine RCs would correspond to ∆[Na/Fe] ≃ 0.23 dex, similar to a globular cluster (GC) with multiple populations. In contrast, the metal-rich stars do not show chemical differences between the bright and faint RC groups. This implies that the double RC observed in the metal-poor component of the bulge might be linked to the multiple populations originating from GC-like subsystems, whereas that of the metal-rich component would have been produced by the X-shaped structure. Our results support previous studies suggesting the composite nature of the Milky Way bulge.

Keywords: Globular star clusters, Milky Way formation, Red giant clump, Stellar populations, Galactic bulge, Spectroscopy
Observational Signatures of AGN Feedback in the Morphology and the Ionization States of Milky Way-like Galaxies. We make an in-depth analysis of different active galactic nuclei (AGN) jet models' signatures, inducing quiescence in galaxies with a halo mass of 1012 M ⊙. Three jet models, including cosmic-ray-dominant, hot thermal, and precessing kinetic jets, are studied at two energy flux levels each, compared to a jet-free, stellar feedback-only simulation. Each of our simulations is idealized isolated galaxy simulations with AGN jet powers that are constant in time and generated using GIZMO and with FIRE stellar feedback. We examine the distribution of Mg II, O VI, and O VIII ions, alongside gas temperature and density profiles. Low-energy ions, like Mg II, concentrate in the interstellar medium (ISM), while higher energy ions, e.g., O VIII, prevail at the AGN jet cocoon's edge. High-energy flux jets display an isotropic ion distribution with lower overall density. High-energy thermal or cosmic-ray jets pressurize at smaller radii, significantly suppressing core density. The cosmic-ray jet provides extra pressure support, extending cool and warm gas distribution. A break in the ion-to-mass ratio slope in O VI and O VIII is demonstrated in the ISM-to-circumgalactic medium (CGM) transition (between 10 and 30 kpc), growing smoothly toward the CGM at greater distances.

Keywords: Galaxy quenching, Active galactic nuclei, Milky Way Galaxy, Ionization
JWST/NIRCam Narrowband Survey of Paβ Emitters in the Spiderweb Protocluster at z = 2.16. We report the initial result of our Paβ narrowband imaging on a protocluster with the JWST Near Infrared Camera (NIRCam). As NIRCam enables deep narrowband imaging of rest-frame near-infrared lines at z &gt; 1, we target one of the most studied protoclusters, the Spiderweb protocluster at z = 2.16, in which previous studies have confirmed more than a hundred member galaxies. The NIRCam F405N narrowband filter covers in the Paβ line the protocluster redshift given by known protocluster members, allowing for the search for new member candidates. The weight-corrected color–magnitude diagram obtained 57 sources showing narrowband excesses, 41 of which satisfy further color selection criteria for limiting the sample to Paβ emitter candidates at z ∼ 2.16, and 24 of them do not have Hα emitter counterparts. The Paβ emitter candidates appear to follow the spatial distribution of known protocluster members; however, follow-up spectroscopic confirmation is required. Only 17 out of 58 known Hα-emitting cluster members are selected as Paβ emitters in the current data, albeit the rest fall out of the narrowband selection owing to their small Paβ equivalent widths. We derive the Paβ luminosity function in the Spiderweb protocluster, showing a normalization density of   at a characteristic Paβ luminosity of  . Furthermore, we examine the possibility of detecting faint line emitters visible only in the narrowband image but find no promising candidates.

Keywords: Galaxy formation, High-redshift galaxy clusters, Protoclusters, Emission line galaxies, Galaxy evolution, Near infrared astronomy