Sazuna/UAT_keywords huggingface dataset:
Radio-loud Quasars above Redshift 4: Very Long Baseline Interferometry (VLBI) Imaging of an Extended Sample. High-redshift radio sources provide plentiful opportunities for studying the formation and evolution of early galaxies and supermassive black holes. However, the number of known radio-loud active galactic nuclei (AGN) above redshift 4 is rather limited. At high redshifts, it appears that blazars, with relativistically beamed jets pointing toward the observer, are in the majority compared to the radio-loud sources with jets misaligned with respect to the line of sight. To find more of these misaligned AGN, milliarcsecond-scale imaging studies carried out with very long baseline interferometry (VLBI) are needed, as they allow us to distinguish between compact-core-jet radio sources and those with more extended emission. Previous high-resolution VLBI studies revealed that some of the radio sources among blazar candidates in fact show unbeamed radio emission on milliarcsecond scales. The most accurate optical coordinates determined with the Gaia astrometric space mission are also useful in the classification process. Here, we report on dual-frequency imaging observations of 13 high-redshift (4 &lt; z &lt; 4.5) quasars at 1.7 and 5 GHz with the European VLBI Network. This sample increases the number of z &gt; 4 radio sources for which VLBI observations are available by about a quarter. Using structural and physical properties, such as radio morphology, spectral index, variability, brightness temperature, as well as optical coordinates, we identified six blazars and six misaligned radio AGNs, with the remaining one tentatively identified as blazar.

Keywords: Very long baseline interferometry, Flat-spectrum radio quasars, Relativistic jets, Radio loud quasars, Active galactic nuclei
Large-scale Multiconfiguration Dirac-Hartree-Fock Calculations for Astrophysics: C-like Ions from O III to Mg VII. Large-scale multiconfiguration Dirac-Hartree-Fock calculations are provided for the n ≤ 5 states in C-like ions from O III to Mg VII. Electron correlation effects are accounted for by using large configuration state function expansions, built from sets of orbitals with principal quantum numbers n ≤ 10. An accurate and complete data set of excitation energies, wavelengths, radiative transition parameters, and lifetimes is offered for the 156 (196, 215, 272, 318) lowest states of the 2s 22p 2, 2s2p 3, 2p 4, 2s 22p3s, 2s 22p3p, 2s 22p3d, 2s2p 23s, 2s2p 23p, 2s2p 23d, 2p 33s, 2p 33p, 2p 33d, 2s 22p4s, 2s 22p4p, 2s 22p4d, 2s 22p4f, 2s2p 24s, 2s2p 24p, 2s2p 24d, 2s2p 24f, 2s 22p5s, 2s 22p5p, 2s 22p5d, 2s 22p5f, and 2s 22p5g configurations in O III (F IV, Ne V, Na VI, Mg VII). By comparing available experimental wavelengths with the MCDHF results, the previous line identifications for the n = 5, 4, 3 → n = 2 transitions of Na VI in the X-ray and EUV wavelength range are revised. For several previous identifications discrepancies are found, and tentative new (or revised) identifications are proposed. A consistent atomic data set including both energy and transition data with spectroscopic accuracy is provided for the lowest hundreds of states for C-like ions from O III to Mg VII.

Keywords: Laboratory astrophysics, Atomic data benchmarking
An Excited-state OH Maser Survey toward WISE Point Sources. We report a survey of excited-state hydroxyl (ex-OH) masers at the 4.7 and 6.0 GHz transitions toward a sample consisting of 3348 massive star-forming region candidates selected from the all-sky Wide-field Infrared Survey Explorer point-source catalog. The survey was conducted with the Shanghai Tianma Radio Telescope. In total, 6, 9, and 30 sources were detected with the ex-OH masers at the 4766, 6031, and 6035 MHz transitions, respectively. Among them, one 4766 MHz, one 6031 MHz, and five 6035 MHz ex-OH maser sources are newly identified. A series of statistical analyses derived that the ex-OH masers were detected efficiently toward the subsamples associated with both the 6.7 GHz CH3OH maser and radio recombination lines (RRLs), whereas compared to the CH3OH masers, the ex-OH masers are more likely to be produced toward the sources with stronger 22 μm band emission. A significant luminosity correlation is found between the ex-OH masers and RRLs. In addition, we found that the magnetic field strength of most sources with the 6.7 GHz CH3OH maser was stronger relative to that of sources without the CH3OH maser. Combined with these, it demonstrates that the ex-OH maser is associated with more evolved star-forming regions, likely associated with thicker dust envelopes. Meanwhile, the ex-OH masers might be a potential tracer for measuring the Galactic magnetic field information on the large-scale views using their Zeeman pairs.

Keywords: Surveys, Star formation, Interstellar molecules, Interstellar masers
LEGWORK: A Python Package for Computing the Evolution and Detectability of Stellar-origin Gravitational-wave Sources with Space-based Detectors. We present LEGWORK (LISA Evolution and Gravitational Wave Orbit Kit), an open-source Python package for making predictions about stellar-origin gravitational-wave sources and their detectability in LISA or other space-based gravitational-wave detectors. LEGWORK can be used to evolve the orbits of sources due to gravitational-wave emission, calculate gravitational-wave strains (using post-Newtonian approximations), compute signal-to-noise ratios, and visualize the results. It can be applied to a variety of potential sources, including binaries consisting of white dwarfs, neutron stars, and black holes. Although we focus on double compact objects, in principle LEGWORK can be used for any system with a user-specified orbital evolution, such as those affected by a third object or gas drag. We optimized the package to make it efficient for use in population studies, which can contain tens of millions of sources. This paper describes the package and presents several potential use cases. We explain in detail the derivations of the expressions behind the package as well as identify and clarify some discrepancies currently present in the literature. We hope that LEGWORK will enable and accelerate future studies triggered by the rapidly growing interest in gravitational-wave sources.

Keywords: Neutron stars, Open source software, Gravitational wave detectors, White dwarf stars, Stellar mass black holes, Orbital evolution, Gravitational waves, Compact objects
Incremental Fermi Large Area Telescope Fourth Source Catalog. We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi Large Area Telescope (LAT) catalog of γ-ray sources. Based on the first 12 years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss the degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources.

Keywords: Sky surveys, Gamma-ray sources, Blazars, Pulsars, Celestial objects catalogs, Gamma-ray astronomy
MUSUBI (MegaCam Ultra-deep Survey: u*-band Imaging) Data for the COSMOS and SXDS Fields. The Subaru Hyper Suprime-Cam (HSC) Strategic Survey is the latest-generation multiband optical imaging survey for galaxy evolution and structure formation. The "Ultra-deep" component of the HSC survey provides grizy broadband images over ~3.4 deg2 to detection limits of ~26-28 AB, along with narrowband images, in the COSMOS and SXDS fields. These images provide an unprecedented combination of depths and area coverage, for studies of galaxies up to z ~ 7. However, the lack of coverage at &lt;4000 Å implies an incomplete sampling of the rest-frame UV at z ≲ 3, which is critically needed for understanding the buildup of stellar mass in later cosmic time. We conducted a multiyear CFHT u*-band imaging campaign in the two HSC Ultra-deep fields with CFHT MegaCam. By including shallower archival data, we reached 5σ depths of u* = 28.1 and 28.4 (AB) at the centers of the COSMOS and SXDS fields, respectively, and u* = 27.7 and 27.8 in the central 1 deg2 fields. The image quality is ≳ 0.″90, fairly good for the u* band. Both the photometric and astrometric quality of our data are excellent. We show that the combination of our u*-band and HSC data can lead to high-quality photometric redshifts at z = 0-3, and robust measurements of rest-frame UV on galaxies at 0.4 &lt; z &lt; 0.6 for distinguishing green-valley galaxies from star-forming and quiescent galaxies. We publicly release our reduced u*-band images and reference catalogs, which can be used readily for scientific studies.

Keywords: Galaxy formation, Astronomy databases, Observational cosmology, Ultraviolet surveys, Green valley galaxies, Galaxy evolution, High-redshift galaxies
Supplement: "An Isolated Mass-gap Black Hole or Neutron Star Detected with Astrometric Microlensing" (2022, ApJL, 933, L23). This supplement provides supporting material for Lam et al. We briefly summarize past gravitational microlensing searches for black holes (BHs) and present details of the observations, analysis, and modeling of five BH candidates observed with both ground-based photometric microlensing surveys and Hubble Space Telescope astrometry and photometry. We present detailed results for four of the five candidates that show no or low probability for the lens to be a BH. In these cases, the lens masses are &lt;2 M ⊙, and two of the four are likely white dwarfs or neutron stars. We also present detailed methods for comparing the full sample of five candidates to theoretical expectations of the number of BHs in the Milky Way (~108).

Keywords: Stellar populations, Astrometry, Astrophysical black holes, Astrometric microlensing effect
Experimental and Theoretical Radiative Parameters of Highly Excited Odd-parity Levels in Ir II. Using the time-resolved laser-induced fluorescence technique, the radiative lifetimes for 15 odd-parity levels from 47,003 to 61,475 cm-1 in Ir II were measured. To the best of our knowledge, 11 lifetime results among these levels are reported for the first time, and hence they should be a good complement to the measured lifetime data of 10 levels previously published in the literature. The pseudorelativistic Hartree-Fock including core-polarization corrections method was used to calculate the lifetimes and branching fractions (BFs) of the investigated energy levels. Combining the experimental lifetime with the theoretical BFs, the transition probabilities and oscillator strengths for 124 transitions were determined.

Keywords: Atomic spectroscopy, Transition probabilities, Radiative processes, Atomic physics
BASS. XXI. The Data Release 2 Overview. The BAT AGN Spectroscopic Survey (BASS) is designed to provide a highly complete census of the key physical parameters of the supermassive black holes (SMBHs) that power local active galactic nuclei (AGNs) (z ≲ 0.3), including their bolometric luminosity (L bol), black hole (BH) mass (M BH), accretion rates (L bol/L Edd), line-of-sight gas obscuration (N H), and the distinctive properties of their host galaxies (e.g., star formation rates, masses, and gas fractions). We present an overview of the second data release of BASS (DR2), an unprecedented spectroscopic AGN survey in spectral range, resolution, and sensitivity, including 1449 optical (∼3200 Å─1 μm) and 233 near-IR (1─2.5 μm) spectra for the brightest 858 ultrahard X-ray (14─195 keV) selected AGNs across the entire sky and essentially all levels of obscuration. This release provides a highly complete set of key measurements (emission-line measurements and central velocity dispersions), with 99.9% measured redshifts and 98% BH masses estimated (for unbeamed AGNs outside the Galactic plane). The BASS DR2 AGN sample represents a unique census of nearby powerful AGNs, spanning over 5 orders of magnitude in AGN bolometric luminosity (L bol ∼ 1040─1047 erg s−1), BH mass (M BH ∼ 105─1010 M ☉), Eddington ratio (L bol/L Edd ≳ 10−5), and obscuration (N H ∼ 1020─1025 cm−2). The public BASS DR2 sample and measurements can thus be used to answer fundamental questions about SMBH growth and its links to host galaxy evolution and feedback in the local universe, as well as open questions concerning SMBH physics. Here we provide a brief overview of the survey strategy, the key BASS DR2 measurements, data sets and catalogs, and scientific highlights from a series of DR2-based works pursued by the BASS team.

Keywords: AGN host galaxies, Supermassive black holes, Sky surveys, X-ray active galactic nuclei, Active galactic nuclei, X-ray surveys
BASS. XXII. The BASS DR2 AGN Catalog and Data. We present the active galactic nucleus (AGN) catalog and optical spectroscopy for the second data release of the Swift BAT AGN Spectroscopic Survey (BASS DR2). With this DR2 release we provide 1449 optical spectra, of which 1182 are released for the first time, for the 858 hard-X-ray-selected AGNs in the Swift BAT 70-month sample. The majority of the spectra (801/1449, 55%) are newly obtained from Very Large Telescope (VLT)/X-shooter or Palomar/Doublespec. Many of the spectra have both higher resolution (R &gt; 2500, N ∼ 450) and/or very wide wavelength coverage (3200─10000 Å, N ∼ 600) that are important for a variety of AGN and host galaxy studies. We include newly revised AGN counterparts for the full sample and review important issues for population studies, with 47 AGN redshifts determined for the first time and 790 black hole mass and accretion rate estimates. This release is spectroscopically complete for all AGNs (100%, 858/858), with 99.8% having redshift measurements (857/858) and 96% completion in black hole mass estimates of unbeamed AGNs (722/752). This AGN sample represents a unique census of the brightest hard-X-ray-selected AGNs in the sky, spanning many orders of magnitude in Eddington ratio (L/L Edd = 10−5─100), black hole mass (M BH = 105─1010 M ☉), and AGN bolometric luminosity (L bol = 1040─1047 erg s−1 ).

Keywords: Sky surveys, Surveys, Seyfert galaxies, X-ray quasars, Active galactic nuclei, X-ray active galactic nuclei, X-ray surveys, Galaxy spectroscopy
BASS. XXIII. A New Mid-infrared Diagnostic for Absorption in Active Galactic Nuclei. In this study, we use the Swift/BAT AGN sample, which has received extensive multiwavelength follow-up analysis as a result of the BAT AGN Spectroscopic Survey, to develop a diagnostic for nuclear obscuration by examining the relationship between the line-of-sight column densities (N H), the 2–10 keV to 12 μm luminosity ratio, and WISE mid-infrared colors. We demonstrate that heavily obscured AGNs tend to exhibit both preferentially "redder" mid-infrared colors and lower values of L X,Obs./L 12 μm than less obscured AGNs, and we derive expressions relating N H to the L X,Obs./L 12 μm and L 22 μm/L 4.6 μm luminosity ratios, as well as develop diagnostic criteria using these ratios. Our diagnostic regions yield samples that are ≳80% complete and ≳60% pure for AGNs with log(N H/cm‑2) ≥ 24, as well as ≳85% pure for AGNs with . We find that these diagnostics cannot be used to differentiate between optically star-forming galaxies and active galaxies. Further, mid-IR contributions from host galaxies that dominate the observed 12 μm emission can lead to larger apparent X-ray deficits and redder mid-IR colors than the AGNs would intrinsically exhibit, though this effect helps to better separate less and more obscured AGNs. Finally, we test our diagnostics on two catalogs of AGNs and infrared galaxies, including the XMM-Newton XXL-N field, and we identify several known Compton-thick AGNs, as well as a handful of candidate heavily obscured AGNs based upon our proposed obscuration diagnostics.

Keywords: AGN host galaxies, Black hole physics, Supermassive black holes, X-ray active galactic nuclei, Active galactic nuclei
BASS. XXIV. The BASS DR2 Spectroscopic Line Measurements and AGN Demographics. We present the second catalog and data release of optical spectral line measurements and active galactic nucleus (AGN) demographics of the BAT AGN Spectroscopic Survey, which focuses on the Swift-BAT hard X-ray detected AGNs. We use spectra from dedicated campaigns and publicly available archives to investigate spectral properties of most of the AGNs listed in the 70 month Swift-BAT all-sky catalog; specifically, 743 of the 746 unbeamed and unlensed AGNs (99.6%). We find a good correspondence between the optical emission line widths and the hydrogen column density distributions using the X-ray spectra, with a clear dichotomy of AGN types for N H = 1022 cm−2. Based on optical emission-line diagnostics, we show that 48%─75% of BAT AGNs are classified as Seyfert, depending on the choice of emission lines used in the diagnostics. The fraction of objects with upper limits on line emission varies from 6% to 20%. Roughly 4% of the BAT AGNs have lines too weak to be placed on the most commonly used diagnostic diagram, [O III]λ5007/Hβ versus [N II]λ6584/Hα, despite the high signal-to-noise ratio of their spectra. This value increases to 35% in the [O III]λ5007/[O II]λ3727 diagram, owing to difficulties in line detection. Compared to optically selected narrow-line AGNs in the Sloan Digital Sky Survey, the BAT narrow-line AGNs have a higher rate of reddening/extinction, with Hα/Hβ &gt; 5 (∼36%), indicating that hard X-ray selection more effectively detects obscured AGNs from the underlying AGN population. Finally, we present a subpopulation of AGNs that feature complex broad lines (34%, 250/743) or double-peaked narrow emission lines (2%, 17/743).

Keywords: AGN host galaxies, Supermassive black holes, Quasars, X-ray active galactic nuclei, Active galactic nuclei
BASS. XXV. DR2 Broad-line-based Black Hole Mass Estimates and Biases from Obscuration. We present measurements of broad emission lines and virial estimates of supermassive black hole masses (M BH) for a large sample of ultrahard X-ray-selected active galactic nuclei (AGNs) as part of the second data release of the BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes M BH estimates for a total of 689 AGNs, determined from the Hα, Hβ, Mg II λ2798, and/or C IV λ1549 broad emission lines. The core sample includes a total of 512 AGNs drawn from the 70 month Swift/BAT all-sky catalog. We also provide measurements for 177 additional AGNs that are drawn from deeper Swift/BAT survey data. We study the links between M BH estimates and line-of-sight obscuration measured from X-ray spectral analysis. We find that broad Hα emission lines in obscured AGNs ( ) are on average a factor of weaker relative to ultrahard X-ray emission and about % narrower than those in unobscured sources (i.e., ). This indicates that the innermost part of the broad-line region is preferentially absorbed. Consequently, current single-epoch M BH prescriptions result in severely underestimated (&gt;1 dex) masses for Type 1.9 sources (AGNs with broad Hα but no broad Hβ) and/or sources with . We provide simple multiplicative corrections for the observed luminosity and width of the broad Hα component (L[bHα] and FWHM[bHα]) in such sources to account for this effect and to (partially) remedy M BH estimates for Type 1.9 objects. As a key ingredient of BASS/DR2, our work provides the community with the data needed to further study powerful AGNs in the low-redshift universe.

Keywords: Supermassive black holes, Surveys, M-sigma relation, Seyfert galaxies, Active galactic nuclei, X-ray surveys, Catalogs
BASS. XXVI. DR2 Host Galaxy Stellar Velocity Dispersions. We present new central stellar velocity dispersions for 484 Sy 1.9 and Sy 2 from the second data release of the Swift/BAT AGN Spectroscopic Survey (BASS DR2). This constitutes the largest study of velocity dispersion measurements in X-ray-selected obscured active galactic nuclei (AGN) with 956 independent measurements of the Ca II H and K λ3969, 3934 and Mg I λ5175 region (3880─5550 Å) and the calcium triplet region (8350─8730 Å) from 642 spectra mainly from VLT/X-Shooter or Palomar/DoubleSpec. Our sample spans velocity dispersions of 40─360 km s1, corresponding to 4─5 orders of magnitude in black hole mass (M BH = 105.5−9.6 M ☉), bolometric luminosity (L bol ∼ 1042─46 erg s−1), and Eddington ratio (L/L Edd ∼ 10−5 to 2). For 281 AGN, our data and analysis provide the first published central velocity dispersions, including six AGN with low-mass black holes (M BH = 105.5−6.5 M ☉), discovered thanks to high spectral resolution observations (σ inst ∼ 25 km s−1). The survey represents a significant advance with a nearly complete census of velocity dispersions of hard X-ray─selected obscured AGN with measurements for 99% of nearby AGN (z &lt; 0.1) outside the Galactic plane (∣b∣ &gt; 10°). The BASS AGN have much higher velocity dispersions than the more numerous optically selected narrow-line AGN (i.e., ∼150 versus ∼100 km s−1) but are not biased toward the highest velocity dispersions of massive ellipticals (i.e., &gt;250 km s−1). Despite sufficient spectral resolution to resolve the velocity dispersions associated with the bulges of small black holes (∼104─5 M ☉), we do not find a significant population of super-Eddington AGN. Using estimates of the black hole sphere of influence from velocity dispersion, direct stellar and gas black hole mass measurements could be obtained with existing facilities for more than ∼100 BASS AGN.

Keywords: AGN host galaxies, Supermassive black holes, Sky surveys, X-ray active galactic nuclei, X-ray surveys