Sazuna/UAT_keywords huggingface dataset:
A 6 cm Formaldehyde Line Survey toward WISE Point Sources. We conducted a 6 cm formaldehyde (H2CO) line survey across the northern sky, targeting 3149 high-mass star-forming region candidates selected from the all-sky Wide-field Infrared Survey Explorer (WISE) point-source catalog using the Shanghai TianMa 65 m Radio Telescope. This survey detected H2CO absorption lines at 1156 positions and four known maser sources, achieving a detection rate of 36.7%. Among these, 14 candidates exhibited hyperfine structure splitting, all located at high Galactic latitudes (b &gt; 3°). The Galactic spatial distribution of H2CO absorption line detections yields a scale height of ∼71.8 pc. Compared to the WISE infrared colors and magnitudes of 6.7 GHz CH3OH masers and hydrogen radio-recombination lines (HRRLs), the distribution of H2CO absorption lines closely resembles that of HRRLs, albeit with higher [W4] magnitudes. The detection of these three lines in the same observational sample enables the classification of H2CO absorption lines into four groups representing distinct evolutionary stages. Variations in H2CO detection proportion, line width, and intensity across these groups probably reflect the influence of star formation feedback on the circumstellar medium during protostellar evolution. Observational updates over six years (2015─2021) of the 6 cm H2CO maser in NGC 7538 IRS1 demonstrate that the flux density diverged from the prediction of the rotating ellipsoidal model, highlighting the need for further data to elucidate the maser variability mechanism.

Keywords: Interstellar line absorption, Star forming regions, Young stellar objects, Interstellar masers, Interstellar medium
Dwarf Galaxy Integral-field Survey (DGIS): Survey Overview and the Results of a Global Mass─Metallicity Relation. Low-mass galaxies are the building blocks of massive galaxies in the framework of hierarchical structure formation. To enable detailed studies of galactic ecosystems in dwarf galaxies by spatially resolving different galactic components, we have carried out the Dwarf Galaxy Integral-field Survey (DGIS). This survey aims to acquire observations with spatial resolutions as high as 10─100 pc while maintaining reasonably high signal-to-noise ratios with the Very Large Telescope/MUSE and ANU-2.3 m/WiFeS. The whole sample will be composed of 63 dwarf galaxies with M* &lt; 109M⊙, selected from the Spitzer Local Volume Legacy survey. The overall scientific goals include studying baryonic cycles in dwarf galaxies, searching for off-nuclear (intermediate)-massive black holes, and quantifying the inner density profiles of dark matter. In this work, we describe the sample selection, data reduction, and high-level data products. By integrating the spectra over the field of view for each galaxy, we obtained the integrated gas-phase metallicity and discussed its dependence on stellar mass and star formation rate (SFR). We find that the overall relation between metallicity and stellar mass of our DGIS nearly follows the extrapolation from the higher mass end. Its dispersion does not decrease by invoking the dependence on SFR.

Keywords: Dwarf galaxies, Astronomy data reduction, Interstellar medium, Spectroscopy
The Reason for the Occurrence of W-type Contact Binaries. For more than half a century, the puzzling W-type phenomenon in contact binaries has challenged astrophysicists. In these systems, the less massive component exhibits a higher surface temperature than its more massive companion, which is a reversal of the typical A-type configuration, where the more massive star is hotter. This counterintuitive temperature inversion defies basic stellar physics and still lacks a widely accepted explanation. In this study, we assembled a sample of over 3000 extensively observed contact binaries and derived their complete set of physical parameters. Our statistical analysis revealed a strong positive correlation between the occurrence of W-type contact binaries and the intensity and frequency of magnetic activities. This result strongly supports the hypothesis that magnetic activities are the primary driver of the W-type phenomenon and offers a compelling explanation for the observed transitions between the W-type and A-type.

Keywords: W Ursae Majoris variable stars, Contact binary stars
The Green Bank Ammonia Survey: Data Release 2. We present an overview of the final data release (DR2) from the Green Bank Ammonia Survey (GAS). GAS is a large program at the Green Bank Telescope to map all Gould Belt star-forming regions with AV ≳ 7 mag visible from the Northern Hemisphere in emission from NH3 and other key molecular tracers. This final release includes the data for all the regions observed: Heiles Cloud 2 and B18 in Taurus; Barnard 1, Barnard 1-E, IC 348, NGC 1333, L1448, L1451, and Per7/34 in Perseus; L1688 and L1689 in Ophiuchus; Orion A (North and South) and Orion B in Orion; Cepheus; B59 in Pipe; Corona Australis East and West; IC 5146; and Serpens Aquila and MWC297 in Serpens. Similar to what was presented in GAS DR1, we find that the NH3 emission and dust continuum emission from Herschel correspond closely. We find that the NH3 emission is generally extended beyond the typical 0.1 pc length scales of dense cores, and we find that the transition between coherent core and turbulent cloud is a common result. This shows that the regions of coherence are common throughout different star-forming regions, with a substantial fraction of the high column density regions displaying subsonic nonthermal velocity dispersions. We produce maps of the gas kinematics, temperature, and NH3 column densities through forward modeling of the hyperfine structure of the NH3 (1,1) and (2,2) lines. We show that the NH3 velocity dispersion, σv, and gas kinetic temperature, TK, vary systematically between the regions included in this release, with an increase in both the mean value and spread of σv and TK with increasing star formation activity. The data presented in this paper are publicly available via doi:10.11570/24.0091.

Keywords: Interstellar molecules, Star formation, Astrochemistry
The ALPINE-CRISTAL-JWST Survey: JWST/IFU Optical Observations for 18 Main-sequence Galaxies at z = 4─6. To fully characterize the formation and evolution of galaxies, we need to observe their stars, gas, and dust on resolved spatial scales. We present the ALPINE-CRISTAL-JWST survey, which combines kiloparsec-resolved imaging and spectroscopy from the Hubble Space Telescope, JWST, and Atacama Large Millimeter/submillimeter Array for 18 representative main-sequence galaxies at z = 4─6 and  log(M*/M⊙)&gt;9.5  to study their star formation, chemical properties, and extended gas reservoirs. The cospatial measurements resolving the ionized gas, molecular gas, stars, and dust on 1─2 kpc scales make this a unique benchmark sample for the study of galaxy formation and evolution at z ∼ 5, connecting the Epoch of Reionization with the cosmic noon. In this paper, we outline the survey goals and sample selection, and present a summary of the available data for the 18 galaxies. In addition, we measure spatially integrated quantities (such as global gas metallicity), test different star formation rate indicators, and quantify the presence of Hα halos. Our targeted galaxies are relatively metal rich (10%─70% solar), complementary to JWST samples at lower stellar mass, and there is broad agreement between different star formation indicators. One galaxy has the signature of an active galactic nuclei (AGN) based on its emission-line ratios. Six show broad Hα emission suggesting type 1 AGN candidates. We conclude with an outlook on the exciting science that will be pursued with this unique sample in forthcoming papers.

Keywords: Galaxy formation, Surveys, Galaxy structure, Galaxy evolution, Interstellar medium, High-redshift galaxies
J-HERTz: J-PLUS Heritage Exploration of Radio Targets at z &lt; 5. We introduce J-HERTZ (J-PLUS Heritage Exploration of Radio Targets at z &lt; 5), a new multiwavelength catalog that combines optical narrowband photometry from J-PLUS, infrared observations from the Wide-field Infrared Survey Explorer, and deep low-frequency radio data from LoTSS for nearly 0.5 million sources across 2100 deg2 of the northern sky. Key innovations of J-HERTZ include Bayesian neural network classifications for 390,000 galaxies, 31,000 quasars, and 20,000 stars, along with significantly improved photometric redshifts for 235,000 galaxies compared to previous J-PLUS DR3 and LoTSS DR2 estimates. We identify 831 candidate Galactic radio stars, which, if confirmed, would constitute a significant addition to the number of radio-emitting stars identified to date. Among radio-loud galaxies with spectroscopic observations, ≳20% lack Seyfert or LINER signatures, indicating a substantial population of optically quiescent radio galaxies, in agreement with previous works. Spectral energy distribution fitting of their host galaxies using J-PLUS photospectra reveals systematically low specific star formation rates, consistent with quenched stellar populations. J-HERTZ thus provides a powerful data set to exploit radio-optical synergies, enabling studies that span from the origin of stellar radio emission to the active galactic nucleus life cycle and the role of jet activity in shaping host galaxy evolution.

Keywords: Quasars, Radio galaxies, Active galactic nuclei, Stellar types, Galaxy quenching, Catalogs
Milliarcsecond-resolution Radio-imaging Survey of Blazar Candidates at 4 &lt; z &lt; 5.4. We present a milliarcsecond-resolution radio survey of 17 high-redshift (4 ≤ z ≤ 5.4) blazar candidates observed with the European Very Long Baseline Interferometry (VLBI) Network at 5 GHz. The primary objective of this study was to investigate the nature of these distant active galactic nuclei (AGNs) and to confirm their blazar nature. Utilizing the technique of VLBI, we obtained high-resolution radio images of compact core and core─jet structures. To confirm the classification of these sources, we collected multiband archival data, including total radio flux densities from single-dish and low-resolution interferometric surveys, optical astrometric positions from Gaia, and X-ray data. These diagnostics collectively help distinguish between blazars and misaligned jetted AGNs. We were able to measure the core brightness temperatures and found that 11 objects show the Doppler-boosted emission expected from blazars. For five additional sources, we do not see evidence of Doppler boosting even if X-ray data suggest that the source is a blazar. These could be either borderline objects or variability may have affected the classifications, considering that the VLBI and X-ray data are not simultaneous. Finally, for the two remaining objects the data suggest a nonblazar classification. Our findings confirm that a significant fraction of these high-redshift radio-loud quasars are blazars and mainly characterized by compact core structures. Overall, the VLBI classifications are consistent with the X-ray classes. This study further increases the sample of VLBI-imaged radio quasars at z ≥ 4 by ∼10%, offering valuable on the population of AGNs in the early Universe.

Keywords: Quasars, Extragalactic radio sources, Blazars, Radio active galactic nuclei, High-redshift galaxies, Interferometry
A Comprehensive Hadronic Code Comparison for Active Galactic Nuclei. We perform the first dedicated comparison of five hadronic codes (AM3, ATHEνA, B13, LeHa-Paris, and LeHaMoC) that have been extensively used in modeling the spectral energy distribution (SED) of jetted active galactic nuclei. The purpose of this comparison is to identify the sources of systematic errors (e.g., implementation method of proton─photon interactions) and to quantify the expected dispersion in numerical SED models computed with the five codes. The outputs from the codes are first tested in synchrotron self-Compton scenarios that are the simplest blazar emission models used in the literature. We then compare the injection rates and spectra of secondary particles produced in pure hadronic cases with monoenergetic and power-law protons interacting on blackbody and power-law photon fields. We finally compare the photon SEDs and the neutrino spectra for realistic proton-synchrotron and leptohadronic blazar models. We find that the codes are in excellent agreement with respect to the spectral shape of the photons and neutrinos. There is a remaining spread in the overall normalization that we quantify, at its maximum, at the level of ±40%. This value should be used as an additional, conservative, systematic uncertainty term when comparing numerical simulations and observations.

Keywords: Radiative transfer simulations, Computational astronomy, Active galactic nuclei
Searching for Dark Structures: A Comparison of Weak-lensing Convergence Maps and Lensing-weighted Galaxy Density Maps. We present the result of a comparison between the dark matter distribution inferred from weak gravitational lensing and the observed galaxy distribution to identify dark structures with a high dark-matter-to-galaxy density ratio. To do this, we use weak-lensing convergence maps from Dark Energy Survey Year 3 data, and construct corresponding galaxy convergence maps at z ≲ 1.0, representing projected galaxy number density fluctuations weighted by lensing efficiency. The two maps show overall agreement. However, we could identify 22 regions where the dark matter density exhibits an excess compared to the galaxy density. After carefully examining the survey depths and proximity to survey boundaries, we select the seven most probable candidates for dark structures. This sample provides valuable test beds for further investigations into dark matter mapping. Moreover, our method will be very useful for future studies of dark structures as large-scale weak-lensing surveys become available, such as the Euclid mission, the Vera C. Rubin Observatory's Legacy Survey of Space and Time, and the Nancy Grace Roman Space Telescope.

Keywords: Weak gravitational lensing, Dark matter distribution, Sky surveys, Large-scale structure of the universe
Radial Gradients and Intrinsic Scatter in MaNGA Galaxies. We derive stellar population parameters and radial gradients within 0.65 Re for spatially resolved spectra of 2968 early-type galaxies from MaNGA, spanning stellar velocity dispersions (σ) of 50─340 km s−1. Light-weighted mean age, C, N, Na, Mg, and Fe abundances are obtained by inverting metallicity-composite stellar population models with isochrones that respond in Teff to individual element abundance changes. Globally, log age increases (∼0.53 dex per decade), [Fe/H] declines slightly (∼─0.06 dex per decade), and [X/Fe] for light elements rises (0.19─0.37 dex per decade for log σ &lt; 2.0 but steepens to nearly double slope for log σ &gt; 2.0) with log σ. [Fe/H] peaks at log σ ≍ 2.0 and falls on either side. Light element [X/Fe] anticorrelates with [Fe/H] (∼─0.1 dex per decade). Astrophysical scatter is largest in low-σ galaxies, especially for Fe and N. Internally, age gradients are nearly flat in low-σ galaxies and slightly negative in high-σ systems (∼─0.04 dex per decade). [Fe/H] radial gradients steepen from −0.06 dex per decade to ─0.15 dex per decade across σ, while light elements (except Na) show ∼─0.03 dex per decade gradients. Scatter in gradients peaks in high-σ galaxies, most strongly for Fe (∼0.23 dex), suggesting comparable numbers of inside-out and outside-in formation. A near-zero (∼─0.03) age and light-element gradient plus mild [Fe/H] gradients supports hierarchical merging for ETG evolution. Simulations match the observed age structure, slope change at log σ ≍ 2.0, and flat gradients, though they overpredict absolute abundances.

Keywords: Galaxy chemical evolution, Galaxy stellar content, Galaxy ages, Galaxy abundances, Galaxy evolution
Can AI Dream of Unseen Galaxies? Conditional Diffusion Model for Galaxy Morphology Augmentation. Observational astronomy relies on visual feature identification to detect critical astrophysical phenomena. While machine learning (ML) increasingly automates this process, models often struggle with generalization in large-scale surveys due to the limited representativeness of labeled datasets—whether from simulations or human annotation—a challenge pronounced for rare yet scientifically valuable objects. To address this, we propose a conditional diffusion model to synthesize realistic galaxy images for augmenting ML training data (hereafter GalaxySD). Leveraging the Galaxy Zoo 2 (GZ2) dataset, which contains visual feature─galaxy image pairs from volunteer annotation, we demonstrate that GalaxySD generates diverse, high-fidelity galaxy images that closely adhere to the specified morphological feature conditions. Moreover, this model enables generative extrapolation to project well-annotated data into unseen domains and advance rare object detection. Integrating synthesized images into ML pipelines improves performance in standard morphology classification, boosting completeness and purity by up to 30% across key metrics. For rare object detection, using early-type galaxies with prominent dust lane features (∼0.1% in the GZ2 dataset) as a test case, our approach doubled the number of detected instances—from 352 to 872—compared to previous studies based on visual inspection. This study highlights the power of generative models to bridge gaps between scarce labeled data and the vast, uncharted parameter space of observational astronomy and sheds insight for future astrophysical foundation model developments. Our project homepage is available at https://galaxysd-webpage.streamlit.app/.

Keywords: Interstellar dust, Neural networks, Astrostatistics techniques, Galaxy physics, Astronomy data analysis, Galaxy classification systems, Outlier detection, Early-type galaxies
Spectroscopic Identification and Population Properties of Cataclysmic Variables from DESI DR1. We present a systematic search for cataclysmic variables (CVs) using spectroscopic data from Data Release 1 of the Dark Energy Spectroscopic Instrument. Applying the Bagging-TopPush algorithm, we identified 433 CV candidates and related objects, of which 412 are confirmed CVs including 76 new systems. Subtypes were assigned through a combination of DESI spectra, Gaia data, and light curves from time-domain surveys, revealing populations of dwarf novae, novalike variables, magnetic CVs, and AM CVn binaries. Orbital periods were constrained from eclipsing light curves and DESI radial velocity curves for 14 systems. For 31 WZ Sge─type dwarf novae, we estimated white dwarf masses and radii by combining Galaxy Evolution Explorer ultraviolet photometry with DESI optical spectra, obtaining average values of 0.82 M⊙ for mass and 13,452 K for effective temperature. We also calculated the strength of the magnetic field for three polars based on the cyclotron features. Furthermore, we derived subtype-dependent space densities and found values consistent, within uncertainties, with those inferred from Sloan Digital Sky Survey, Gaia, and other survey data, though remaining lower than theoretical predictions by 1─2 orders of magnitude. Besides, we highlight several notable objects, including newly identified AM CVn systems, eclipsing systems in the period gap, donor-dominated binaries, and other unusual systems of particular interest for follow-up observations.

Keywords: White dwarf stars, Dwarf novae, Photometry, Spectroscopy, Cataclysmic variable stars, AM Herculis stars
Fast Protoplanetary Disk Modeling with DUSTRAD: A Dust Evolution and Radiative Transfer Module for FARGO3D. We present DUSTRAD, a dust evolution and radiative transfer module for the FARGO3D hydrodynamic code, designed to efficiently simulate key aspects of long-term protoplanetary disk evolution. The dust evolution employs a two-population scheme to track fine and coarse grains, while the radiative transfer uses a fast moment method to compute midplane heating from stellar irradiation across the disk's surface. These components are coupled with 2D vertically averaged hydrodynamics in the r─ϕ plane and an analytic vertical (z) density profile to evaluate the radiative effects. Our tests demonstrate that the dust evolution performs comparably to previous two-population implementations in 2D hydrodynamics. We compare the radiative transfer to RADMC3D, and the temperature results agree within 15% around various substructures and shadows. With reasonable choices for the resolution of the radiative transfer, DUSTRAD achieves run times within a factor of 10 of standard 2D hydrodynamic runs with dust using the MULTIFLUID package for FARGO3D. Applications of the module to intermediate-mass planets in low-viscosity disks show inward migration can be significantly slowed with the inclusion of radiative transfer, even reversing direction for some gap-opening planets.

Keywords: Computational methods, Radiative transfer, Protoplanetary disks, Hydrodynamics
Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. V. Dramatic Variability in High-ionization Broad Emission Lines. We present a systematic search for changing-look (CL) quasars at high redshift z &gt; 0.9 by crossmatching the spectroscopic data sets from the Dark Energy Spectroscopic Instrument Data Release 1 and Sloan Digital Sky Survey Data Release 18. We identify 97 CL quasars showing significant variability in high-ionization broad emission lines, including 45 turn-on and 52 turn-off events, corresponding to a detection rate of ∼0.042%. The low rate relative to low-ionization CL quasar searches is likely due to selection and physical effects in high-ionization lines. Based on the CL quasar sample, we find that CL quasars generally exhibit lower accretion rates compared to typical quasars, with average Eddington ratios of  logλEdd  ∼ −1.14 in the bright state and ∼−1.39 in the dim state, compared to ∼−0.65 for typical quasars. Furthermore, while high-ionization lines in CL quasars follow the Baldwin effect on a population level, some sources can display inverse Baldwin trends. In addition, we find a positive correlation between the variability in high-ionization lines (e.g., Mg II, C III]) and the change in bolometric luminosity. We also estimate a characteristic rest-frame timescale of ∼3 yr for CL transitions, with no significant difference between turn-on and turn-off cases. Taken as a whole, these findings support an accretion-driven origin of the CL phenomenon, and provide new insights into the variability of high-ionization emission lines.

Keywords: Accretion, Supermassive black holes