Sazuna/UAT_keywords huggingface dataset:
On the Relation between Kappa Distribution Functions and the Plasma Beta Parameter in the Earth's Magnetosphere: THEMIS Observations. The Earth's magnetosphere represents a natural plasma laboratory that allows us to study the behavior of particle distribution functions in the absence of Coulomb collisions, typically described by the kappa distributions. We have investigated the properties of these functions for ions and electrons in different magnetospheric regions, thereby making it possible to reveal the κ-parameters for a wide range of plasma beta (β) values (from 10-3 to 102). This was done using simultaneous ion and electron measurements from the five Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft spanning the years 2008-2018. It was found that for a fixed plasma β, the κ-index and core energy (Ec) of the distribution can be modeled by the power law $\kappa ={{AE}}_{c}^{\gamma }$ &lt;!-- --&gt; for both species, and the relation between β, κ, and Ec is much more complex than earlier reported: both A and γ exhibit systematic dependencies with β. Our results indicate that β ∼ 0.1-0.3 is a range where the plasma is more dynamic, since it is influenced by both the magnetic field and temperature fluctuations, which suggests that the transition between magnetically and kinetically dominated plasmas occurs at these values of β. For β &gt; 1, both A and γ take nearly constant values, a feature that is especially notable for the electrons and might be related to their demagnetization. The relation between β, κ, and Ec that we present is an important result that can be used by theoretical models in the future.

Keywords: Interplanetary medium, Space plasmas, Magnetohydrodynamics, Plasma physics, Plasma astrophysics, Planetary magnetospheres
Superflares, Chromospheric Activities, and Photometric Variabilities of Solar-type Stars from the Second-year Observation of TESS and Spectra of LAMOST. In this work, 1272 superflares on 311 stars are collected from 22,539 solar-type stars from the second-year observation of the Transiting Exoplanet Survey Satellite (TESS), which almost covered the northern hemisphere of the sky. Three superflare stars contain hot Jupiter candidates or ultrashort-period planet candidates. We obtain γ = -1.76 ± 0.11 of the correlation between flare frequency and flare energy ( ${dN}/{dE}\propto {E}^{-\gamma }$ &lt;!-- --&gt; ) for all superflares and get β = 0.42 ± 0.01 of the correlation between superflare duration and energy (Tduration ∝ Eβ), which supports that a similar mechanism is shared by stellar superflares and solar flares. Stellar photometric variability (Rvar) is estimated for all solar-type stars, and the relation of $E\propto {R}_{\mathrm{var}}^{3/2}$ &lt;!-- --&gt; is included. An indicator of chromospheric activity (S-index) is obtained by using data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) for 7454 solar-type stars. Distributions of these two properties indicate that the Sun is generally less active than superflare stars. We find that saturation-like feature of Rvar ∼ 0.1 may be the reason for superflare energy saturating around 1036 erg. Object TIC 93277807 was captured by the TESS first-year mission and generated the most energetic superflare. This superflare is valuable and unique in that it can be treated as an extreme event, which may be generated by different mechanisms than other superflares.

Keywords: Stellar flares, G stars
Mini-EUSO Mission to Study Earth UV Emissions on board the ISS. Mini-EUSO is a telescope observing the Earth in the ultraviolet band from the International Space Station. It is a part of the JEM-EUSO program, paving the way to future larger missions, such as K-EUSO and POEMMA, devoted primarily to the observation of ultrahigh-energy cosmic rays from space. Mini-EUSO is capable of observing extensive air showers generated by ultrahigh-energy cosmic rays with an energy above 1021 eV and to detect artificial showers generated with lasers from the ground. Other main scientific objectives of the mission are the search for nuclearites and strange quark matter, the study of atmospheric phenomena such as transient luminous events, meteors, and meteoroids, the observation of sea bioluminescence and of artificial satellites and man-made space debris. Mini-EUSO will map the nighttime Earth in the UV range (290-430 nm), with a spatial resolution of about 6.3 km and a temporal resolution of 2.5 μs, through a nadir-facing UV-transparent window in the Russian Zvezda module. The instrument, launched on 2019 August 22, from the Baikonur Cosmodrome, is based on an optical system employing two Fresnel lenses and a focal surface composed of 36 multianode photomultiplier tubes, 64 channels each, for a total of 2304 channels with single-photon counting sensitivity and an overall field of view of 44°. Mini-EUSO also contains two ancillary cameras to complement measurements in the near-infrared and visible ranges. In this paper, we describe the detector and present the various phenomena observed in the first months of operations.

Keywords: Earth atmosphere, Earth ionosphere, Ultraviolet telescopes, Meteors, Ultra-high-energy cosmic radiation, Lightning
X-Ray-to-radio Offset Inference from Low-count X-Ray Jets. Observations of positional offsets between the location of X-ray and radio features in many resolved, extragalactic jets indicates that the emitting regions are not cospatial, an important piece of evidence in the debate over the origin of the X-ray emission on kiloparsec scales. The existing literature is nearly exclusively focused on jets with sufficiently deep Chandra observations to yield accurate positions for X-ray features, but most of the known X-ray jets are detected with tens of counts or fewer, making detailed morphological comparisons difficult. Here we report the detection of X-ray-to-radio positional offsets in 15 extragalactic jets from an analysis of 22 sources with low-count Chandra observations, where we utilized the Low-count Image Reconstruction Algorithm. This algorithm has allowed us to account for effects such as Poisson background fluctuations and nearby point sources which have previously made the detection of offsets difficult in shallow observations. Using this method, we find that in 55% of knots with detectable offsets, the X-rays peak upstream of the radio, questioning the applicability of one-zone models, including the IC/CMB model for explaining the X-ray emission. We also report the nondetection of two previously claimed X-ray jets. Many, but not all, of our sources follow a loose trend of increasing offset between the X-ray and radio emission, as well as a decreasing X-ray-to-radio flux ratio along the jet.

Keywords: X-ray astronomy, High energy astrophysics, Relativistic jets, Astronomy data analysis, Active galactic nuclei, Astronomical methods
Revisiting the Fundamental Parameters of 49 New Star Clusters in Gaia DR2. Reliable fundamental parameters of star clusters such as distance modulus, metallicity, age, extinction, and binary fraction are of key importance for astrophysical studies. Although a lot of new star clusters were identified from the data of, e.g., Gaia Data Release 2 (Gaia DR2), the fundamental parameters of many clusters were not determined reliably. This work makes use of the photometry data of Gaia DR2 and a good color-magnitude diagram (CMD) analysis tool, Powerful CMD, to determine the fundamental parameters of 49 new star clusters in detail. All CMDs are fitted carefully by both statistics and by eye, to make sure the CMDs are reproduced as well as possible. As a result, the fundamental parameters of 22 clusters are determined reliably, and those of the others are also determined as well as we can. Because the width of the main sequence in the color direction is used, combined with other widely used CMD features to constrain the fundamental parameters, the results of this work are more reliable than those reported by single-star isochrone fits. As a feature of this work, the primordial binary fractions and rotating star fractions of star clusters have been reported, which are useful for many works, in particular for some simulation research.

Keywords: Open star clusters, Star clusters
The Hα Dots Survey. IV. A Fourth List of Faint Emission-line Objects. We present the fourth catalog of serendipitously discovered compact extragalactic emission-line sources—Hα Dots. A total of 454 newly discovered objects are included in the current survey list. These objects have been detected in searches of moderately deep narrowband images acquired for the ALFALFA Hα project. The catalog of Hα Dots presented in the current paper was derived from searches carried out using ALFALFA Hα images obtained with the KPNO 2.1 m telescope. This results in a substantially deeper sample of Dots compared to our previous lists, which were all discovered in images taken with the WIYN 0.9 m telescope. The median R-band magnitude of the current catalog is 21.59, more than 1.6 mag fainter than the median for the 0.9 m sample (a factor of 4.4× fainter). Likewise, the median emission-line flux of the detected sources is a factor of 4.3× fainter. The line flux completeness limit of the current sample is ~3 × 10-16 erg s-1 cm-2. We present accurate coordinates, apparent magnitudes, and narrowband line fluxes for each object in the sample. Unlike our previous lists of Hα Dots, the current sample does not include follow-up spectroscopy.

Keywords: Starburst galaxies, Blue compact dwarf galaxies, Quasars, Dwarf galaxies, Emission line galaxies, Seyfert galaxies, Star formation
The Synchrotron-based Far-infrared Spectrum of Glycolaldehyde. Glycolaldehyde (GA) has been observed toward several different sources, with a broad range of rotational temperatures (8-300 K). At the high end, the temperature is comparable to the energy of the lowest vibrational states of GA, making the vibrational contribution to the partition function significant. Here, we report an analysis of the high-resolution far-infrared spectrum of GA, which features a plethora of well-resolved lines from 170-430 cm-1 (13-5 THz). We focus on the three fundamental vibrational bands in this range, i.e., the symmetric ν12 bend at 282 cm-1, and the asymmetric ν17 and ν18 torsions at 360 and 208 cm-1, respectively. We assigned 23,266 transitions to 13,999 lines within these bands, which, when combined with the previously reported microwave and millimeter-wave spectra, allowed for refinement of the vibrationally excited rotational constants, and accurate determination of their band origins. Additionally, the assignment of a number of lines in several hot bands that are significantly populated at 300 K allowed for determination of their band origins. The rotational constants reported here should be useful in searches of vibrationally excited GA toward warm sources, and the accurately determined band origins allow for refinement of the vibrational partition function, and therefore column density, for a given excitation temperature.

Keywords: Molecular physics, Molecular spectroscopy, Interstellar medium
Presolar Silicate and Oxide Grains Found in Lithic Clasts from Isheyevo and the Fine-grained Matrix of Northwest Africa 801. We report on the discovery of 33 oxygen-anomalous grains from the CH3/CBb3 chondrite Isheyevo and the CR2 chondrite Northwest Africa (NWA) 801. Oxygen isotopic compositions indicate the origin of the majority grains in stellar outflows of low-mass (∼1.2 to ∼2.2 M⊙), solar-metallicity red giant or asymptotic giant branch stars, while highly 17O-enriched grains probably have nova origins. Isotopic compositions of the eight 18O-rich grains, including an extremely 18O-rich grain (∼16 times solar 18O/16O ratio), are reproduced by zone mixing of SNe II ejecta. Close-to-normal silicon, magnesium, and calcium isotopic compositions of grains are consistent with the isotope exchange in the interstellar medium or the meteorite parent body, while two grains with Si isotopic anomalies and one grain with Mg isotopic anomalies reflect the Galactic chemical evolution. An Isheyevo clast showed several hot spots with moderate to high 15N enrichments, including a hot spot with an extreme 15N excess of (7225 ± 316)‰. However, no correlation between 15N enrichment and presolar oxygen-rich grain abundance is found. Grains with elliptical shapes probably indicate primary condensation feature. Two complex grains possibly display decoupling of the isotopic and elemental compositions in the grain formation environments. The low silicate-to-oxide abundance ratio for the fine-grained chondrule rims in NWA 801 likely reflects the preferential destruction of silicates due to terrestrial weathering. In NWA 801, the presolar O-rich grain abundance in fine-grained chondrule rims is higher than in the interchondrule matrix, similar to the trend observed for some aqueously altered chondrites of petrologic type 2.

Keywords: Silicate grains, Type II supernovae, Carbonaceous chondrites, Novae, Asymptotic giant branch stars, Meteorites, Circumstellar dust
The Araucaria Project: Deep Near-infrared Photometric Maps of Local and Sculptor Group Galaxies. I. Carina, Fornax, and Sculptor. Deep near-infrared (NIR) J- and K-band photometry of three Local Group dwarf spheroidal galaxies—Fornax, Carina, and Sculptor—is made available for the community. Until now, these data have only been used by the Araucaria Project to determine distances using the tip of the red giant branch and RR Lyrae stars. Now, we present the entire data collection in the form of a database, consisting of accurate J- and K-band magnitudes, sky coordinates, ellipticity measurements, and timestamps of observations, complemented by stars' loci in their reference images. The depth of our photometry reaches about 22 mag at the 5σ level, and is comparable to NIR surveys, such as the UKIRT Infrared Deep Sky Survey (UKIDSS) or the VISTA Hemisphere Survey (VHS). Small overlap with VHS and no overlap with UKIDSS makes our database a unique source of quality photometry.

Keywords: Observational astronomy, Dwarf galaxies, Astronomy databases, Infrared photometry
Testing the High-latitude Curvature Effect of Gamma-Ray Bursts with Fermi Data: Evidence of Bulk Acceleration in Prompt Emission. When a gamma-ray burst (GRB) emitter stops emission abruptly, the observer receives rapidly fading emission from high latitudes with respect to the line of sight, known as the "curvature effect." Identifying such emission from GRB prompt-emission lightcurves would constrain the radius of prompt emission from the central engine and the composition of GRB jets. We perform a dedicated search of high-latitude emission (HLE) through spectral and temporal analyses of a sample of single-pulse bursts detected by the Gamma-ray Burst Monitor on board the Fermi satellite. We identify HLE from a subsample of bursts and constrain the emission radius to be RGRB ∼ (1015-1016) cm from the central engine. Some bursts have the HLE decay faster than predicted by a constant Lorentz factor jet, suggesting that the emission region is undergoing acceleration during prompt emission. This supports the Poynting-flux-dominated jet composition for these bursts. The conclusion is consistent with previous results drawn from spectral-lag modeling of prompt emission and HLE analysis of X-ray flares.

Keywords: Gamma-ray bursts, Relativistic jets, Astronomy data analysis
SiO, <SUP>29</SUP>SiO, and <SUP>30</SUP>SiO Emission from 67 Oxygen-rich Stars: A Survey of 61 Maser Lines from 7 to 1 mm. Circumstellar environments of oxygen-rich stars are among the strongest SiO maser emitters. Physical processes such as collisions, infrared pumping, and overlaps favor the inversion of level population and produce maser emission at different vibrational states. Despite numerous observational and theoretical efforts, we still do not have a unified picture including all of the physical processes involved in SiO maser emission. The aim of this work is to provide homogeneous data in a large sample of oxygen-rich stars. We present a survey of 67 oxygen-rich stars from 7 to 1 mm, in their rotational transitions from J = 1 → 0 to J = 5 → 4, for vibrational numbers v from 0 to 6 in the three main SiO isotopologs. We have used one of the 34 m NASA antennas at Robledo and the IRAM 30 m radio telescope. The first tentative detection of a v = 6 line is reported, as well as the detection of new maser lines. The highest vibrational levels seem confined to small volumes, presumably close to the stars. The J = 1 → 0, v = 2 line flux is greater than the corresponding v = 1 in almost half of the sample, which may confirm a predicted dependence on the pulsation cycle. This database is potentially useful in models which should consider most of the physical agents, time dependency, and mass-loss rates. As a by-product, we report detections of 27 thermal rotational lines from other molecules, including isotopologs of SiS, H2S, SO, SO2, and NaCl.

Keywords: Interstellar molecules, Circumstellar envelopes, Asymptotic giant branch, Surveys, Silicon monoxide masers, Interstellar medium, Radio astronomy, Stellar evolution
Stellar Parameterization of LAMOST M Dwarf Stars. The M dwarf stars are the most common stars in the Galaxy, dominating the population of the Galaxy at faint magnitudes. Precise and accurate stellar parameters for M dwarfs are of crucial importance for many studies. However, the atmospheric parameters of M dwarf stars are difficult to determine. In this paper, we present a catalog of the spectroscopic stellar parameters (Teff and [M/H]) of ∼300,000 M dwarf stars observed by both LAMOST and Gaia using the Stellar LAbel Machine (SLAM). We train a SLAM model using LAMOST spectra with APOGEE Data Release 16 labels with 2800 K &lt; Teff &lt; 4500K and -2 dex &lt; [M/H] &lt; 0.5 dex. The SLAM Teff is in agreement to within ∼50 K compared to the previous study determined by APOGEE observations, and the SLAM [M/H] agrees within 0.12 dex compared to the APOGEE observation. We also set up a SLAM model trained by the BT-Settl atmospheric model with random uncertainties (in cross validation) to 60 K and agreeing within ∼90 K compared to previous studies.

Keywords: M dwarf stars, Low mass stars, Astronomy data analysis, Catalogs
The Central Engines of Fermi Blazars. We present a catalog of central engine properties, i.e., black hole mass (MBH) and accretion luminosity (Ldisk), for a sample of 1077 blazars detected with the Fermi Large Area Telescope. This includes broad emission-line systems and blazars whose optical spectra lack emission lines but are dominated by the absorption features arising from the host galaxy. The average MBH for the sample is $\langle \mathrm{log}\,{M}_{\mathrm{BH},\mathrm{all}{M}_{\odot }}\rangle =8.60$ &lt;!-- --&gt; , and there is evidence suggesting the association of more massive black holes with absorption-line systems. Our results indicate a bimodality of Ldisk in Eddington units (Ldisk/LEdd) with broad-line objects tend to have a higher accretion rate (Ldisk/LEdd &gt; 0.01). We have found that Ldisk/LEdd and Compton dominance (CD; the ratio of the inverse Compton to synchrotron peak luminosities) are positively correlated at the &gt;5σ confidence level, suggesting that the latter can be used to reveal the state of accretion in blazars. Based on this result, we propose a CD-based classification scheme. Sources with CD &gt; 1 can be classified as high-Compton-dominated or HCD blazars, whereas those with CD ≲ 1 are low-Compton-dominated (LCD) objects. This scheme is analogous to that based on the mass accretion rate proposed in the literature; however, it overcomes the limitation imposed by the difficulty in measuring Ldisk and MBH for objects with quasi-featureless spectra. We conclude that the overall physical properties of Fermi blazars are likely to be controlled by the accretion rate in Eddington units. The catalog is made public at http://www.ucm.es/blazars/engines and Zenodo.

Keywords: Supermassive black holes, BL Lacertae objects, Black holes, Blazars, Spectral line identification, Radio loud quasars
Inferring Solar Differential Rotation through Normal-mode Coupling Using Bayesian Statistics. Normal-mode helioseismic data analysis uses observed solar oscillation spectra to infer perturbations in the solar interior due to global and local-scale flows and structural asphericity. Differential rotation, the dominant global-scale axisymmetric perturbation, has been tightly constrained primarily using measurements of frequency splittings via "a-coefficients." However, the frequency-splitting formalism invokes the approximation that multiplets are isolated. This assumption is inaccurate for modes at high angular degrees. Analyzing eigenfunction corrections, which respect cross-coupling of modes across multiplets, is a more accurate approach. However, applying standard inversion techniques using these cross-spectral measurements yields a-coefficients with a significantly wider spread than the well-constrained results from frequency splittings. In this study, we apply Bayesian statistics to infer a-coefficients due to differential rotation from cross-spectra for both f-modes and p-modes. We demonstrate that this technique works reasonably well for modes with angular degrees ℓ = 50-291. The inferred a3-coefficients are found to be within 1 nHz of the frequency-splitting values for ℓ &gt; 200. We also show that the technique fails at ℓ &lt; 50 owing to the insensitivity of the measurement to the perturbation. These results serve to further establish mode-coupling as an important helioseismic technique with which to infer internal structure and dynamics, both axisymmetric (e.g., meridional circulation) and non-axisymmetric perturbations.

Keywords: Helioseismology, Solar differential rotation, Solar oscillations, Markov chain Monte Carlo
Revisiting Rotation Measures from the Canadian Galactic Plane Survey: the Magnetic Field in the Disk of the Outer Galaxy. Faraday rotation provides a valuable tracer of magnetic fields in the interstellar medium; catalogs of Faraday rotation measures provide key observations for studies of the Galactic magnetic field. We present a new catalog of rotation measures derived from the Canadian Galactic Plane Survey, covering a large region of the Galactic plane spanning 52° &lt; l &lt; 192°, -3° &lt; b &lt; 5°, along with northern and southern latitude extensions around l ≈ 105°. We have derived rotation measures for 2234 sources (4 of which are known pulsars), 75% of which have no previous measurements, over an area of approximately 1300 deg2. These new rotation measures increase the measurement density for this region of the Galactic plane by a factor of 2.

Keywords: Polarimetry, Catalogs, Milky Way magnetic fields