Sazuna/UAT_keywords huggingface dataset:
Wavelengths and Energy Levels of Singly Ionized Nickel (Ni II) Measured Using Fourier Transform Spectroscopy. High-resolution spectra of singly ionized nickel (Ni II) have been recorded using Fourier transform spectroscopy in the region 143-5555 nm (1800-70,000 cm-1) with continuous, nickel-helium hollow cathode discharge sources. An extensive analysis of identified Ni II lines resulted in the confirmation and revision of 283 previously reported energy levels, from the ground state up to the 3d 8( M  L)6s subconfigurations. Typical energy-level uncertainties are a few thousandths of a cm-1, representing at least an order-of-magnitude reduction in uncertainty with respect to previous measurements. Twenty-five new energy levels have now been established and are reported here for the first time. Eigenvector compositions of the energy levels have been calculated using the orthogonal operator method. In total, 159 even and 149 odd energy levels and 1424 classified line wavelengths of Ni II are reported and will enable more accurate and reliable analyses of Ni II in astrophysical spectra.

Keywords: Spectral line lists, Line positions, Spectral line identification, Laboratory astrophysics, Stellar atmospheric opacity, Atomic spectroscopy, Spectroscopy, Atomic data benchmarking, Stellar spectral lines
A Model RRNet for Spectral Information Exploitation and LAMOST Medium-resolution Spectrum Parameter Estimation. This work proposes a residual recurrent neural network (RRNet) for synthetically extracting spectral information and estimating stellar atmospheric parameters together with 15 chemical element abundances for medium-resolution spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). The RRNet consists of two fundamental modules: a residual module and a recurrent module. The residual module extracts spectral features based on the longitudinally driving power from parameters, while the recurrent module recovers spectral information and restrains the negative influences from noises based on Cross-band Belief Enhancement. RRNet is trained by the spectra from common stars between LAMOST DR7 and the APOGEE-Payne catalog. The 17 stellar parameters and their uncertainties for 2.37 million medium-resolution spectra from LAMOST DR7 are predicted. For spectra with a signal-to-noise ratio ≥ 10, the precision of estimations (T eff and log g) are 88 K and 0.13 dex, respectively, elements C, Mg, Al, Si, Ca, Fe, and Ni are 0.05-0.08 dex, and N, O, S, K, Ti, Cr, and Mn are 0.09-0.14 dex, while that of Cu is 0.19 dex. Compared with StarNet and SPCANet, RRNet shows higher accuracy and robustness. In comparison to Apache Point Observatory Galactic Evolution Experiment and Galactic Archaeology with HERMES surveys, RRNet manifests good consistency within a reasonable range of bias. Finally, this work releases a catalog of 2.37 million medium-resolution spectra from the LAMOST DR7, the source code, the trained model, and the experimental data, respectively, for astronomical science exploration and data-processing algorithm research reference.

Keywords: Stellar abundances, Stellar atmospheres, Astronomy data analysis, Spectroscopy
Molecular Gas Structures Traced by <SUP>13</SUP>CO Emission in the 18,190 <SUP>12</SUP>CO Molecular Clouds from the MWISP Survey. After morphological classification of 18,190 12CO molecular clouds, we further investigate the properties of their internal molecular gas structures traced by the 13CO (J = 1-0) line emissions. Using three different methods to extract the 13CO gas structures within each 12CO cloud, we find that ~15% of the 12CO clouds (2851) have 13CO gas structures and these 12CO clouds contribute about 93% of the total integrated flux of 12CO emission. In each of the 2851 12CO clouds with 13CO gas structures, the 13CO emission area generally does not exceed 70% of the 12CO emission area, and the 13CO integrated flux does not exceed 20% of the 12CO integrated flux. We reveal a strong correlation between the velocity-integrated intensities of 12CO lines and those of 13CO lines in both 12CO and 13CO emission regions. This indicates the H2 column densities of molecular clouds are crucial for the 13CO line emission. After linking the 13CO structure detection rates of the 18,190 12CO molecular clouds to their morphologies, i.e., nonfilaments and filaments, we find that the 13CO gas structures are primarily detected in 12CO clouds with filamentary morphologies. Moreover, these filaments tend to harbor more than one 13CO structure. That demonstrates filaments not only have larger spatial scales, but also have more molecular gas structures traced by 13CO lines, i.e., local gas density enhancements. Our results favor the turbulent compression scenario for filament formation, in which dynamical compression of turbulent flows induces local density enhancements. The nonfilaments tend to be in the low-pressure and quiescent turbulent environments of the diffuse interstellar medium.

Keywords: Interstellar molecules, Molecular clouds, Interstellar medium
The DECam Local Volume Exploration Survey Data Release 2. We present the second public data release (DR2) from the DECam Local Volume Exploration survey (DELVE). DELVE DR2 combines new DECam observations with archival DECam data from the Dark Energy Survey, the DECam Legacy Survey, and other DECam community programs. DELVE DR2 consists of ~160,000 exposures that cover &gt;21,000 deg2 of the high-Galactic-latitude (∣b∣ &gt; 10°) sky in four broadband optical/near-infrared filters (g, r, i, z). DELVE DR2 provides point-source and automatic aperture photometry for ~2.5 billion astronomical sources with a median 5σ point-source depth of g = 24.3, r = 23.9, i = 23.5, and z = 22.8 mag. A region of ~17,000 deg2 has been imaged in all four filters, providing four-band photometric measurements for ~618 million astronomical sources. DELVE DR2 covers more than 4 times the area of the previous DELVE data release and contains roughly 5 times as many astronomical objects. DELVE DR2 is publicly available via the NOIRLab Astro Data Lab science platform.

Keywords: Surveys, Local Group, Catalogs
The California Legacy Survey. III. On the Shoulders of (Some) Giants: The Relationship between Inner Small Planets and Outer Massive Planets. We use a high-precision radial velocity survey of FGKM stars to study the conditional occurrence of two classes of planets: close-in small planets (0.023-1 au, 2-30 M ⊕) and distant giant planets (0.23-10 au, 30-6000 M ⊕). We find that ${41}_{-13}^{+15} \% $ of systems with a close-in, small planet also host an outer giant, compared to ${17.6}_{-1.9}^{+2.4} \% $ for stars irrespective of small planet presence. This implies that small planet hosts may be enhanced in outer giant occurrences compared to all stars with 1.7σ significance. Conversely, we estimate that ${42}_{-13}^{+17} \% $ of cold giant hosts also host an inner small planet, compared to ${27.6}_{-4.8}^{+5.8} \% $ of stars irrespective of cold giant presence. We also find that more massive and close-in giant planets are not associated with small inner planets. Specifically, our sample indicates that small planets are less likely to have outer giant companions more massive than approximately 120 M ⊕ and within 0.3-3 au, than to have less massive or more distant giant companions, with ~2.2σ confidence. This implies that massive gas giants within 0.3-3 au may suppress inner small planet formation. Additionally, we compare the host-star metallicity distributions for systems with only small planets and those with both small planets and cold giants. In agreement with previous studies, we find that stars in our survey that only host small planets have a metallicity distribution that is consistent with the broader solar-metallicity-median sample, while stars that host both small planets and gas giants are distinctly metal rich with ~2.3σ confidence.

Keywords: Exoplanets
Survey of Near-infrared Diffuse Interstellar Bands in Y and J Bands. I. Newly Identified Bands. We searched for diffuse interstellar bands (DIBs) in the 0.91 &lt; λ &lt; 1.33 μm region by analyzing the near-infrared (NIR) high-resolution (R = 20,000 and 28,000) spectra of 31 reddened early-type stars (0.04 &lt; E(B - V) &lt; 4.58) and an unreddened reference star. The spectra were collected using the WINERED spectrograph, which was mounted on the 1.3 m Araki telescope at Koyama Astronomical Observatory, Japan, in 2012-2016, and on the 3.58 m New Technology Telescope at La Silla Observatory, Chile, in 2017-2018. We detected 54 DIBs-25 of which are newly detected by this study-and eight DIB candidates. Using this updated list, the DIB distributions over a wide wavelength range, from optical to NIR, are investigated. The FWHM values of the NIR DIBs are found to be narrower than those of the optical DIBs, on average, which suggests that the DIBs at longer wavelengths tend to be caused by larger molecules. Assuming that the larger carriers are responsible for the DIBs at longer wavelengths, and have larger oscillator strengths, we found that the total column densities of the DIB carriers tend to decrease with increasing DIB wavelength. The candidate molecules and ions for the NIR DIBs are also discussed.

Keywords: Interstellar molecules, Diffuse interstellar bands, Interstellar dust extinction, Interstellar medium
EMPRESS. V. Metallicity Diagnostics of Galaxies over 12 + log(O/H) ≃ 6.9-8.9 Established by a Local Galaxy Census: Preparing for JWST Spectroscopy. We present optical-line gas metallicity diagnostics established by the combination of local SDSS galaxies and the largest compilation of extremely metal-poor galaxies (EMPGs) including new EMPGs identified by the Subaru EMPRESS survey. A total of 103 EMPGs are included, covering a large parameter space of magnitude (M  i  = -19 to -7) and Hβ equivalent width (10-600 Å), i.e., wide ranges of stellar mass and star formation rate. Using reliable metallicity measurements from the direct method for these galaxies, we derive the relationships between strong optical-line ratios and gas-phase metallicity over the range of $12+\mathrm{log}({\rm{O}}/{\rm{H}})$ ≃ 6.9-8.9, corresponding to 0.02-2 solar metallicity Z ⊙. We confirm that the R23 index, ([O III]+[O II])/Hβ, is the most accurate metallicity indicator with a metallicity uncertainty of 0.14 dex over the range among various popular metallicity indicators. The other metallicity indicators show large scatters in the metal-poor range (≲0.1 Z ⊙). It is explained by our CLOUDY photoionization modeling that, unlike the R23 index, the other metallicity indicators do not use a sum of singly and doubly ionized lines and cannot trace both low- and high-ionization gas. We find that the accuracy of the metallicity indicators is significantly improved if one uses Hβ equivalent width measurements that tightly correlate with ionization states. In this work, we also present the relation of physical properties with the UV-continuum slope β and ionization production rate ξ ion derived with GALEX data for the EMPGs and provide local anchors of galaxy properties together with the optical-line metallicity indicators that are available in the form of a machine-readable table and useful for forthcoming JWST spectroscopic studies.

Keywords: Galaxy chemical evolution, Dwarf galaxies, Chemical abundances, Ultraviolet astronomy, Galaxy evolution
X-Ray Intraday Variability of the TeV Blazar Markarian 421 with XMM-Newton. Highly variable Markarian 421 is a bright high-synchrotron energy peaked blazar showing a wide featureless nonthermal spectrum, making it a good candidate for our study of intraday flux and spectral variations over time. We analyze its X-ray observations over 17 yr, taken with the EPIC-pn instrument, to probe into the intraday variability properties, focusing on the photon energy band of 0.3-10.0 keV, and its soft (0.3-2.0 keV) and hard (2.0-10.0 keV) subbands. To examine the flux variability, fractional variability amplitudes and minimum variability timescales have been calculated. We also probed into the spectral variability by studying the hardness ratio for each observation, the correlation between the two energy bands, using the discrete correlation function, and inspecting the normalized light curves. The parameters obtained from these methods were studied for any correlations or nonrandom trends. From this work, we speculate on the constraints on the possible particle acceleration and emission processes in the jet, for a better understanding of the processes involving turbulent behavior, except for shocks. A positive discrete correlation function between the two subbands indicates the role of the same electron population in the emission of photons in the two bands. A correlation between the parameter of flux variability and the parameters of spectral variation and lags in the subenergy bands provides the constraints to be considered for any modeling of emission processes.

Keywords: X-ray astronomy, Hardness ratio, Blazars, Active galaxies, Active galactic nuclei
A CO Survey of the Entire Northern Sky. We present a very large extension of the Galactic plane CO survey of Dame et al. to the entire northern sky (δ &gt; -17°). The extension was carried out with the same telescope as was used for the plane survey, the CfA 1.2 m, and perfectly meshes with its irregular boundaries in latitude. A total of 382,202 CO(1-0) spectra uniformly sample the high-latitude sky with a true-angle spacing of 0.°25 or better. The final reduced and folded spectra have a uniform sensitivity of 0.18 K in 0.65 km s-1 channels and provide a velocity coverage of ±47.1 km s-1. We describe the observational techniques and the data reduction and provide various summary maps of the spatial and velocity distributions of CO emission over the northern sky, and a catalog of the molecular clouds we found there. We also describe the CO spectral line data cubes that we have made available online.

Keywords: Interstellar molecules, Interstellar line emission, Molecular clouds, Solar neighborhood, Diffuse molecular clouds
The Velocity Map Asymmetry of Ionized Gas in MaNGA. I. The Catalog and General Properties. The SDSS-IV MaNGA survey has measured two-dimensional maps of emission-line velocities for a statistically powerful sample of nearby galaxies. The asymmetric features of these kinematics maps reflect the nonrotational component of a galaxy's internal motion of ionized gas. In this study, we present a catalog of kinematic asymmetry measurements of the Hα velocity map of a sample of 5353 MaNGA galaxies. Based on this catalog, we find that "special" galaxies (e.g., merging galaxies, barred galaxies, and active galactic nucleus host galaxies) contain more galaxies with highly asymmetric velocity maps. However, we notice that more than half of galaxies with high kinematic asymmetry in our sample are quite "regular." For those "regular" galaxies, kinematic asymmetry shows a significant anticorrelation with stellar mass at $\mathrm{log}{M}_{\star }\lt 9.7$ , while such a trend becomes very weak at $\mathrm{log}{M}_{\star }\gt 9.7$ . Moreover, at a given stellar mass, the kinematic asymmetry shows weak correlations with photometric morphology, star formation rate, and environment, while it is independent of H I gas content. We also have quantified the observational effects in the kinematic asymmetry measurement. We find that both the signal-to-noise ratio of Hα flux and disk inclination angle contribute to the measures of kinematic asymmetry, while the physical spatial resolution is an irrelevant factor inside the MaNGA redshift coverage.

Keywords: Galaxy formation, Galaxy structure, Galaxy kinematics, Galaxies
A Blind All-sky Search for Star Clusters in Gaia EDR3: 886 Clusters within 1.2 kpc of the Sun. Although previous searches for star clusters have been very successful, many clusters are likely still omitted, especially at high-Galactic-latitude regions. In this work, based on the astrometry of Gaia EDR3, we searched nearby (ϖ &gt; 0.8 mas) all-sky regions, obtaining 886 star clusters, of which 270 candidates have not been cataloged before. At the same time, we have presented the physical parameters of the clusters by fitting theoretical isochrones to their optical magnitudes. More halo members and expanding structures in many star clusters were also found. Most of the new objects are young clusters that are less than 100 million years old. Our work greatly increased the sample size and physical parameters of star clusters in the solar neighborhood, in particular, 46 clusters are newly found with ∣b∣ &gt; 20°, which represents a nearly threefold increase in the number of clusters at high-Galactic-latitude regions. The figure sets of all clusters are also available at China-VO via https://doi.org/10.12149/101133.

Keywords: Open star clusters, Star clusters
Mining S-PLUS for Metal-poor Stars in the Milky Way. This work presents the medium-resolution (R ~ 1500) spectroscopic follow-up of 522 low-metallicity star candidates from the Southern Photometric Local Universe Survey (S-PLUS). The objects were selected from narrowband photometry, taking advantage of the metallicity-sensitive S-PLUS colors. The follow-up observations were conducted with the Blanco and Gemini South telescopes, using the COSMOS and GMOS spectrographs, respectively. The stellar atmospheric parameters (T eff, $\mathrm{log}\,g$ , and [Fe/H]), as well as carbon and α-element abundances, were calculated for the program stars in order to assess the efficacy of the color selection. Results show that ${92}_{-3}^{+2} \% $ of the observed stars have [Fe/H] ≤ -1.0, ${83}_{-3}^{+3} \% $ have [Fe/H] ≤ -2.0, and ${15}_{-3}^{+3} \% $ have [Fe/H] ≤ -3.0, including two ultra metal-poor stars ([Fe/H] ≤ -4.0). The 80th percentile for the metallicity cumulative distribution function of the observed sample is [Fe/H] = -2.04. The sample also includes 68 carbon-enhanced metal-poor stars. Based on the calculated metallicities, further S-PLUS color cuts are proposed, which can increase the fractions of stars with [Fe/H] ≤ -1.0 and ≤ -2.0 to 98% and 88%, respectively. Such high success rates enable targeted high-resolution spectroscopic follow-up efforts, as well as provide selection criteria for fiber-fed multiplex spectroscopic surveys.

Keywords: Narrow band photometry, Metallicity, Chemical abundances, Stellar atmospheres
Osaka Feedback Model. II. Modeling Supernova Feedback Based on High-resolution Simulations. Feedback from supernovae (SNe) is an essential mechanism that self-regulates the growth of galaxies, and a better model of SN feedback is still needed in galaxy-formation simulations. In the first part of this paper, using an Eulerian hydrodynamic code ATHENA++, we find the universal scaling relations for the time evolution of momentum and radius for a superbubble, when the momentum and time are scaled by those at the shell-formation time. In the second part of this paper, we develop a SN feedback model based on the ATHENA++ simulation results utilizing Voronoi tessellation around each star particle, and implement it into the GADGET3-OSAKA smoothed particle hydrodynamic code. Our feedback model was demonstrated to be isotropic and conservative in terms of energy and momentum. We examined the mass/energy/metal loading factors and find that our stochastic thermal feedback model produced galactic outflow that carries metals high above the galactic plane but with weak suppression of star formation. Additional mechanical feedback further suppressed star formation and brought the simulation results into better agreement with the observations of the Kennicutt-Schmidt relation, with all the results being within the uncertainties of observed data. We argue that both thermal and mechanical feedback are necessary for the SN feedback model of galaxy evolution when an individual SN bubble is unresolved.

Keywords: Hydrodynamical simulations, Galaxy formation, Galactic winds, Stellar feedback, Star formation, Interstellar medium, Supernovae, Galaxies, Superbubbles
Characteristics of Kepler Eclipsing Binaries Displaying a Significant O'Connell Effect. The O'Connell effect-the presence of unequal maxima in eclipsing binaries-remains an unsolved riddle in the study of close binary systems. The Kepler space telescope produced high-precision photometry of nearly 3000 eclipsing binary systems, providing a unique opportunity to study the O'Connell effect in a large sample and in greater detail than in previous studies. We have characterized the observational properties-including temperature, luminosity, and eclipse depth-of a set of 212 systems (7.3% of Kepler eclipsing binaries) that display a maxima flux difference of at least 1%, representing the largest sample of O'Connell effect systems yet studied. We explored how these characteristics correlate with each other to help understand the O'Connell effect's underlying causes. We also describe some system classes with peculiar light-curve features aside from the O'Connell effect (~24% of our sample), including temporal variation and asymmetric minima. We found that the O'Connell effect size's correlations with period and temperature are inconsistent with Kouzuma's starspot study. Up to 20% of systems display the parabolic eclipse timing variation signal expected for binaries undergoing mass transfer. Most systems displaying the O'Connell effect have the brighter maximum following the primary eclipse, suggesting a fundamental link between which maximum is brighter and the O'Connell effect's physical causes. Most importantly, we find that the O'Connell effect occurs exclusively in systems where the components are close enough to significantly affect each other, suggesting that the interaction between the components is ultimately responsible for causing the O'Connell effect.

Keywords: Eclipsing binary stars, Interacting binary stars, Close binary stars
A Multifluid Dust Module in Athena++: Algorithms and Numerical Tests. We describe the algorithm, implementation, and numerical tests of a multifluid dust module in the Athena++ magnetohydrodynamic code. The module can accommodate an arbitrary number of dust species interacting with the gas via aerodynamic drag (characterized by the stopping time), with a number of numerical solvers. In particular, we describe two second-order accurate, two-stage, fully implicit solvers that are stable in stiff regimes, including short stopping times and high dust mass loading, and they are paired with the second-order explicit van Leer and Runge-Kutta gas dynamics solvers in Athena++, respectively. Moreover, we formulate a consistent treatment of dust concentration diffusion with dust back-reaction, which incorporates momentum diffusion and ensures Galilean invariance. The new formulation and stiff drag solvers are implemented to be compatible with most of the existing features of Athena++, including different coordinate systems, mesh refinement, and shearing box and orbital advection. We present a large suite of test problems, including the streaming instability in linear and nonlinear regimes, as well as local and global settings, which demonstrate that the code achieves the desired performance. This module will be particularly useful for studies of dust dynamics and planet formation in protoplanetary disks.

Keywords: Computational methods, Protoplanetary disks, Hydrodynamics