Sazuna/UAT_keywords huggingface dataset:
Spitzer Catalog of Herschel-selected Ultrared Dusty Star-forming Galaxies. The largest Herschel extragalactic surveys, H-ATLAS and HerMES, have selected a sample of “ultrared” dusty star-forming galaxies (DSFGs) with rising SPIRE flux densities (S 500 &gt; S 350 &gt; S 250; the so-called “500 μm risers”) as an efficient way for identifying DSFGs at higher redshift (z &gt; 4). In this paper, we present a large Spitzer follow-up program of 300 Herschel ultrared DSFGs. We have obtained high-resolution Atacama Large Millimeter/submillimeter Array, Northern Extended Millimeter Array, and SMA data for 63 of them, which allow us to securely identify the Spitzer/IRAC counterparts and classify them as gravitationally lensed or unlensed. Within the 63 ultrared sources with high-resolution data, ∼65% appear to be unlensed and ∼27% are resolved into multiple components. We focus on analyzing the unlensed sample by directly performing multiwavelength spectral energy distribution modeling to derive their physical properties and compare with the more numerous z ∼ 2 DSFG population. The ultrared sample has a median redshift of 3.3, stellar mass of 3.7 × 1011 M ☉, star formation rate (SFR) of 730 M ☉ yr-1, total dust luminosity of 9.0 × 1012 L ☉, dust mass of 2.8 × 109 M ☉, and V-band extinction of 4.0, which are all higher than those of the ALESS DSFGs. Based on the space density, SFR density, and stellar mass density estimates, we conclude that our ultrared sample cannot account for the majority of the star-forming progenitors of the massive, quiescent galaxies found in infrared surveys. Our sample contains the rarer, intrinsically most dusty, luminous, and massive galaxies in the early universe that will help us understand the physical drivers of extreme star formation.

Keywords: Starburst galaxies, High-redshift galaxies
The Carnegie-Irvine Galaxy Survey. VIII. Demographics of Bulges along the Hubble Sequence. We present multicomponent decomposition of high-quality R-band images of 320 disk galaxies from the Carnegie-Irvine Galaxy Survey. In addition to bulges and disks, we successfully model nuclei, bars, disk breaks, nuclear/inner lenses, and inner rings. Our modeling strategy treats nuclear rings and nuclear bars as part of the bulge component, while other features such as spiral arms, outer lenses, and outer rings are omitted from the fits because they are not crucial for accurate bulge measurements. The error budget of bulge parameters includes the uncertainties from sky-level measurements and model assumptions. Comparison with multicomponent decomposition from the Spitzer Survey of Stellar Structure in Galaxies reveals broad agreement for the majority of the overlapping galaxies, but for a considerable fraction of galaxies there are significant differences in bulge parameters caused by different strategies in model construction. We confirm that on average bulge prominence decreases from early- to late-type disk galaxies, although the large scatter of bulge-to-total ratios in each morphological bin limits the application of Hubble type as an accurate predictor of bulge-to-total ratio. In contrast with previous studies claiming that barred galaxies host weaker bulges, we find that barred and unbarred spiral galaxies have similar bulge prominence.

Keywords: Galaxy structure, Galaxy bulges, Galaxy photometry, Disk galaxies
A Census of Early-phase High-mass Star Formation in the Central Molecular Zone. We present new observations of the C-band continuum emission and masers to assess high-mass (&gt;8 {M}⊙ ) star formation at early evolutionary phases in the inner 200 pc of the Central Molecular Zone (CMZ) of the Galaxy. The continuum observation is complete to free-free emission from stars above 10-11 {M}⊙  in 91% of the covered area. We identify 104 compact sources in the continuum emission, among which five are confirmed ultracompact H II regions, 12 are candidates of ultracompact H II regions, and the remaining 87 sources are mostly massive stars in clusters, field stars, evolved stars, pulsars, extragalactic sources, or of unknown nature that is to be investigated. We detect class II CH3OH masers at 23 positions, among which six are new detections. We confirm six known H2CO masers in two high-mass star-forming regions and detect two new H2CO masers toward the Sgr C cloud, making it the ninth region in the Galaxy that contains masers of this type. In spite of these detections, we find that current high-mass star formation in the inner CMZ is only taking place in seven isolated clouds. The results suggest that star formation at early evolutionary phases in the CMZ is about 10 times less efficient than expected from the dense gas star formation relation, which is in line with previous studies that focus on more evolved phases of star formation. This means that if there will be any impending, next burst of star formation in the CMZ, it has not yet begun.

Keywords: Galactic center, Star formation, H II regions, Astrophysical masers
Quasar Properties from the Sloan Digital Sky Survey. II. The Quasars Obtained by the SDSS-IV in the First Two Years. This work aims to measure the properties of continuum and emission lines around C IV, Mg II, Hβ, and Hα for the quasars observed by the extended Baryon Oscillation Spectroscopic Survey (eBOSS) during the first two years. We determine the quasar redshifts based on narrow [O III] λ5007, broad Mg II λ2799, and/or C IV λ1548 emission lines. The comparisons between the visual inspection redshifts included in DR14Q and the redshifts determined by us suggest that the visual inspection redshifts would be robust. We also infer the virial black hole mass of quasars based on C IV, Mg II, Hβ, and/or Hα broad emission lines, using empirical relationships reported by previous studies. Systematic differences are remarkable among different line-based mass estimators reported by previous studies. Using the empirical relationship (Equation (1)), we improve the line-based mass estimators by recalibrating new coefficient (a, b), so that different line-based mass estimators are more consistent. We find that (a, b) = (0.96, 0.5), (0.91, 0.5), (0.82, 0.5), and (0.77, 0.5) are the best choices for the Hα-, Hβ-, Mg II-, and C IV-based mass estimators, respectively. All these above properties are publicly available. We also find that the line and continuum luminosities are tightly correlated with each other. The Balmer lines show a negative Baldwin effect, while the metal lines display a positive Baldwin effect. In addition, we find that tight correlations are indwelled in different line luminosities.

Keywords: Black hole physics, Active galaxies, Astronomy data reduction, Quasars
A Particle Module for the PLUTO Code. III. Dust. Implementation of a new particle module describing the physics of dust grains coupled to a gas via drag forces is the subject of this work. The proposed particle-gas hybrid scheme has been designed to work in Cartesian as well as in cylindrical and spherical geometries. The numerical method relies on a Godunov-type second-order scheme for the fluid and an exponential midpoint rule for dust particles, which overcomes the stiffness introduced by the linear coupling term. Besides being time-reversible and globally second-order accurate in time, the exponential integrator provides energy errors that are always bounded, and it remains stable in the limit of arbitrarily small particle stopping times, yielding the correct asymptotic solution. Such properties make this method preferable to the more widely used semi-implicit or fully implicit schemes at a very modest increase in computational cost. Coupling between particles and grid quantities is achieved through particle deposition and field-weighting techniques borrowed from particle-in-cell simulation methods. In this respect, we derive new weight factors in curvilinear coordinates that are more accurate than traditional volume or area weighting. A comprehensive suite of numerical benchmarks is presented to assess the accuracy and robustness of the algorithm in Cartesian, cylindrical, and spherical coordinates. Particular attention is devoted to the streaming instability, which is analyzed in both local and global disk models. The module is part of the PLUTO code for astrophysical gas dynamics, and it is mainly intended for the numerical modeling of protoplanetary disks in which solid and gas interact via aerodynamic drag.

Keywords: Computational methods, Astrophysical fluid dynamics, Protoplanetary disks, Hydrodynamics
A Staggered Semi-analytic Method for Simulating Dust Grains Subject to Gas Drag. Numerical simulations of dust-gas dynamics are one of the fundamental tools in astrophysical research, such as the study of star and planet formation. It is common to find tightly coupled dust and gas in astrophysical systems, which demands that any practical integration method be able to take time steps, {{Δ }}t, much longer than the stopping time, {t}{{s}}, due to drag. A number of methods have been developed to ensure stability in this stiff ({{Δ }}t\gg {t}{{s}}) regime, but there remains large room for improvement in terms of accuracy. In this paper, we describe an easy-to-implement method, the “staggered semi-analytic method” (SSA), and conduct numerical tests to compare it to other implicit and semi-analytic methods, including the second-order implicit method and the Verlet method. SSA makes use of a staggered step to better approximate the terminal velocity in the stiff regime. In applications to protoplanetary disks, this not only leads to orders of magnitude higher accuracy than the other methods, but also provides greater stability, making it possible to take time steps 100 times larger in some situations. SSA is also second-order accurate and symplectic when {{Δ }}t\ll {t}{{s}}. More generally, the robustness of SSA makes it applicable to linear dust-gas drag in virtually any context.

Keywords: Interstellar dust, Computational astronomy, Very small grains, Exoplanet formation, Astrophysical dust processes, Circumstellar matter, Computational methods, Protoplanetary disks, Interstellar dust processes, Circumstellar dust, Debris disks
Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. III. Survey Overview. We present 0.″25 resolution (35 au) ALMA 1.3 mm dust polarization observations for 37 young stellar objects (YSOs) in the Ophiuchus molecular cloud. These data encompass all the embedded protostars in the cloud and several flat-spectrum and Class II objects to produce the largest, homogeneous study of dust polarization on disk scales to date. The goal of this study is to study dust polarization morphologies down to disk scales. We find that 14/37 (38%) of the observed YSOs are detected in polarization at our sensitivity. Nine of these sources have uniform polarization angles, and four sources have azimuthal polarization structure. We find that the sources with uniform polarization tend to have steeper inclinations (&gt;60°) than those with azimuthal polarization (&lt;60°). Overall, the majority (9/14) of the detected sources have polarization morphologies and disk properties consistent with dust self-scattering processes in optically thick disks. The remaining sources may be instead tracing magnetic fields. Their inferred field directions from rotating the polarization vectors by 90° are mainly poloidal or hourglass shaped. We find no evidence of a strong toroidal field component toward any of our disks. For the 23 YSOs that are undetected in polarization, roughly half of them have 3σ upper limits of &lt;2%. These sources also tend to have inclinations &lt;60°, and they are generally compact. Since lower-inclination sources tend to have azimuthal polarization, these YSOs may be undetected in polarization owing to unresolved polarization structure within our beam. We propose that disks with inclinations &gt;60° are the best candidates for future polarization studies of dust self-scattering, as these systems will generally show uniform polarization vectors that do not require very high resolution to resolve. We release the continuum and polarization images for all the sources with this publication. Data from the entire survey can be obtained from Dataverse.

Keywords: Astrospheres, Magnetic fields, Star formation, Protoplanetary disks, Circumstellar dust, Polarimetry
A Search for Intrinsic H I 21 cm and OH 18 cm Absorption toward Compact Radio Sources. We present the results of a large search for intrinsic H I 21 cm and OH 18 cm absorption in 145 compact radio sources in the redshift range 0.02 &lt; z &lt; 3.8 with the Green Bank Telescope. We redetect H I 21 cm absorption toward six known absorption systems, but detect no new H I or OH absorption in 102 interference-free sources. Seventy-nine sources have not previously been observed for H I 21 cm absorption. We recover a mean optical depth limit of τ 3σ  &lt; 0.023 for all the nondetections in the survey. Our results do not support the high intrinsic absorption rates found by previous studies in compact radio sources at low redshift. Our results do, however, support the hypothesis proposed by Curran et al. that high ultraviolet (UV) luminosity active galactic nuclei do not show intrinsic H I 21 cm absorption, confirming a threshold of L UV = 1023 W Hz-1, above which our intrinsic absorption fraction is zero (54 sources). The exact nature of the UV luminosity effect on H I absorption systems remains ambiguous. We additionally find no statistical correlation between the 1.4 GHz radio luminosity or the source size and the 21 cm absorption detection rate. We attribute the lack of intrinsic absorption in our survey to the UV luminosity effect caused by an optical selection bias and a decreased column density sensitivity with increasing redshift due to lower radio continuum flux densities, high radio frequency interference, and higher telescope system temperatures at low frequencies.

Keywords: Quasar absorption line spectroscopy, Active galaxies, Galaxy nuclei, Interstellar medium, Radio sources, Galaxies
The Third Data Release of the Beijing-Arizona Sky Survey. The Beijing-Arizona Sky Survey (BASS) is a wide and deep imaging survey that covers a 5400 deg2 area in the northern Galactic cap with the 2.3 m Bok telescope using two filters (g and r bands). The Mosaic z-band Legacy Survey (MzLS) covers the same area in the z band with the 4 m Mayall telescope. These two surveys will be used for spectroscopic targeting by the Dark Energy Spectroscopic Instrument (DESI) in the northernmost portion of the DESI footprint. This paper describes the third data release (DR3) of BASS, which contains the photometric data from all BASS and MzLS observations from 2015 January until the completion of BASS in 2019 March. The median astrometric precision relative to Gaia positions is about 17 mas and the median photometric offset relative to the Pan-STARRS1 photometry is within 5 mmag. The median 5σ AB magnitude depths for point sources are 24.2, 23.6, and 23.0 mag for the g, r, and z bands, respectively. The photometric depth within the survey area is highly homogeneous, and the difference between the 20% and 80% depth is less than 0.3 mag. The DR3 data, including raw data, calibrated single-epoch images, single-epoch photometric catalogs, stacked images, and co-added photometric catalogs, are publicly accessible at http://batc.bao.ac.cn/BASS/doku.php?id=datarelease:home.

Keywords: Observational astronomy, Catalogs, Sky surveys, Astronomy data reduction
Globular Cluster Intrinsic Iron Abundance Spreads. I. Catalog. We present an up-to-date catalog of intrinsic iron abundance spreads in the 55 Milky Way globular clusters (GCs) for which sufficiently precise spectroscopic measurements are available. Our method combines multiple data sets when possible to improve the statistics, taking into account the fact that different methods and instruments can lead to systematically offset metallicities. Only high spectral resolution (R &gt; 14,000) studies that measure the equivalent widths of individual iron lines are found to have uncertainties on the metallicities of the individual stars that can be calibrated sufficiently well for the intrinsic dispersion to be separated cleanly from a random measurement error. The median intrinsic iron spread is found to be 0.045 dex, which is small but unambiguously measured to be nonzero in most cases. There is large variation between clusters, but more luminous GCs, above 105 L ⊙, have increasingly large iron spreads on average; no trend between the iron spread and metallicity is found.

Keywords: Globular star clusters, Stellar abundances, Catalogs, Astrostatistics strategies
The 2MASS Redshift Survey in the Zone of Avoidance. The Two Micron All-Sky Survey (2MASS) Redshift Survey was started two decades ago with the goal of mapping the three-dimensional distribution of an all-sky flux-limited (K  s  &lt; 11.75 mag) sample of ∼45,000 galaxies. Our first data release presented an unprecedented uniform coverage for most of the celestial sphere, with redshifts for ∼98% of our sample. However, we were missing redshifts for ∼18% of the catalog entries that were located within the “Zone of Avoidance” (| b| &lt; 10^\circ )—an important region of the sky for studies of the large-scale structure and cosmic flows. In this second and final data release, we present redshifts for all 1041 2MRS galaxies that previously lacked this information, as well as updated measurements for 27 others.

Keywords: Redshift surveys, Catalogs, Large-scale structure of the universe
Relativistic MR-MP Energy Levels for L-shell Ions of Iron. A comprehensive set of level energies is provided for the valence and K-vacancy states of the ions Fe XVII, Fe XVIII, Fe XIX, Fe XX, Fe XXI, Fe XXII, Fe XXIII, and Fe XXIV. Level energies were calculated with the relativistic Multi-Reference Møller-Plesset Perturbation Theory method (MR-MP). The data set includes level energies coming from the configurations 1{s}22{(s,p)}q, 1{s}22{(s,p)}q-1{nl}, 1{s}12{(s,p)}q+1, 1{s}12{(s,p)}q{nl}, 2{(s,p)}q+2, and 2{(s,p)}q+1{nl}, where 1 ≤ q ≤ 8, n ≤ 5, and l ≤ 3. The results have been compared with data from the National Institute of Standards and Technology (NIST) online database and with previous calculations. In general, the deviation from the NIST-recommended values is below 0.6 and 1.0 eV for valence and K-vacancy level energies, respectively. However, we identify numerous outliers among the NIST-recommended values. The extensive data set presented here greatly augments the amount of available reference level energies in the NIST database for L-shell ions of Fe, and we expect our data set to ease line identification and confirm level designations.

Keywords: Line positions, Atomic physics, Atomic spectroscopy, Spectroscopy, Atomic data benchmarking
Could HCN Be Responsible for the Formamide Synthesis in Earth’s Primitive Atmosphere?. The forward and reverse H2O + HCN ↔ HCONH2 global reactions were studied along temperatures from 200 to 4000 K. Equilibrium geometries and vibrational frequencies were obtained from calculations at the Coupled Cluster theory with single and double excitations (CCSD)/cc-pVDZ level; whereas enthalpies, Gibbs energies, and thermal rate constants were achieved by means of the CCSD(T)/CBS//CCSD/cc-pVDZ combined treatment. The estimates performed considering physical and chemical conditions proposed for the primitive atmosphere of Earth indicate that the formamide concentration might be 3.0-4.4 times larger than the one for HCN at 700 K, suggesting that this forward gas phase reaction could provide an efficient production route for formamide during an age just before the formation of early oceans. This route is also considerably fast once the chemical equilibrium is attained in some decades at this temperature. In short, our research reinforces that more complex organic compounds, such as formamide, could be synthetized in the Earth’s primordial atmosphere, even considering a neutral atmosphere scenario composed mainly by H2O, CO2, and some N2.

Keywords: Reaction rates, Chemical abundances, Astrochemistry
The Relationship between 6.7 GHz Methanol Masers and Radio Recombination Lines in High-mass Star-forming Regions. We report a systematic survey of a 6.7 GHz Class II methanol maser toward a sample of 448 sources selected from the Red Midcourse Space Experiment Source catalog. These sample sources are composed of high-mass star-forming region (HMSFR) candidates and have been studied as tracers of HMSFRs, such as water masers or radio continuum emission of ultracompact H II region. The survey was conducted using the Shanghai Tianma Radio Telescope. Through the observations, we simultaneously studied the 4.7 and 6.0 GHz excited-state interstellar hydroxyl (OH) maser lines and 10 hydrogen radio recombination lines (RRLs) in the C band. In total, we detected 6.7 GHz methanol masers and RRLs from 102 and 116 sources, respectively. In addition, 4, 3, and 10 sources exhibit OH masers at 4765.56, 6030.75, and 6035.09 MHz transitions, respectively. Through the survey, we identified four new 6.7 GHz methanol maser sources and three new excited-state OH maser sources (one at 4750 MHz and two at 6035 MHz). The statistical analysis demonstrated that there is a positive correlation of luminosity between 6.7 GHz methanol masers and RRLs. A good correlation of integrated luminosity between radio continuum emission and the 6.7 GHz methanol masers is presented with respect to the RRL emission sources. The average of the integrated luminosities of the RRLs in the sources with 6.7 GHz masers is greater than those without the 6.7 GHz masers; similarly, the average of integrated luminosities of the 6.7 GHz methanol masers in the sources with RRLs is greater than those without the RRLs. Moreover, we found that the averages of the emission measure and electron temperature of H II regions associated with 6.7 GHz methanol masers are larger than those without the 6.7 GHz methanol masers. This suggests that the masers are most likely produced in high gas density and luminous regions with brighter RRLs and higher radio continuum emission.

Keywords: Interstellar molecules, Surveys, Star formation, Astrophysical masers, Interstellar medium, H II regions
Cluster Difference Imaging Photometric Survey. I. Light Curves of Stars in Open Clusters from TESS Sectors 6 and 7. The Transiting Exoplanet Survey Satellite (TESS) is providing precise time-series photometry for most star clusters in the solar neighborhood. Using the TESS images, we have begun a Cluster Difference Imaging Photometric Survey, in which we are focusing both on stars that are candidate cluster members and on stars that show indications of youth. Our aims are to discover giant transiting planets with known ages, and to provide light curves suitable for studies in stellar astrophysics. For this work, we made 159,343 light curves of candidate young stars, across 596 distinct clusters. Each light curve represents between 20 and 25 days of observations of a star brighter than G  Rp  = 16, with 30-minute sampling. We describe the image-subtraction and time-series analysis techniques we used to create the light curves, which have noise properties that agree with theoretical expectations. We also comment on the possible utility of the light-curve sample for studies of stellar rotation evolution and binary eccentricity damping. The light curves, which cover about one-sixth of the galactic plane, are available at archive.stsci.edu/hlsp/cdips.

Keywords: Astronomy data reduction, Stellar ages, Time series analysis, Exoplanet evolution, Eclipsing binary stars, Variable stars, Stellar rotation, Open star clusters, Transit photometry, Stellar associations