Sazuna/UAT_keywords huggingface dataset:
Galaxy and Mass Assembly (GAMA): A WISE Study of the Activity of Emission-line Systems in G23. We present a detailed study of emission-line systems in the Galaxy And Mass Assembly (GAMA) G23 region, making use of Wide-field Infrared Survey Explorer (WISE) photometry that includes carefully measured resolved sources. After applying several cuts to the initial catalog of ∼41,000 galaxies, we extract a sample of 9809 galaxies. We then compare the spectral diagnostic Baldwin, Philips &amp; Terlevich (BPT) classification of 1154 emission-line galaxies (38% resolved in W1) to their location in the WISE color-color diagram, leading to the creation of a new zone for mid-infrared "warm" galaxies located 2&amp;sgr; above the star-forming sequence, below the standard WISE active galactic nucleus (AGN) region. We find that the BPT and WISE diagrams agree on the classification for 85% and 8% of the galaxies as non-AGN (star-forming = SF) and AGN, respectively, and disagree on ∼7% of the entire classified sample. Thirty-nine percent of the AGNs (all types) are broad-line systems for which the [N II] and [Hα] fluxes can barely be disentangled, giving in most cases spurious [N II]/[Hα] flux ratios. However, several optical AGNs appear to be completely consistent with SF in WISE. We argue that these could be low-power AGNs, or systems whose hosts dominate the IR emission. Alternatively, given the sometimes high [O III] luminosity in these galaxies, the emission lines may be generated by shocks coming from super-winds associated with SF rather than AGN activity. Based on our findings, we have created a new diagnostic: [W1 - W2] versus [N II]/[Hα], which has the virtue of separating SF from AGNs and high-excitation sources. It classifies 3 to ∼5 times more galaxies than the classic BPT.

Keywords: AGN host galaxies, Infrared galaxies, Galaxy evolution
Prediction of the In Situ Coronal Mass Ejection Rate for Solar Cycle 25: Implications for Parker Solar Probe In Situ Observations. The Parker Solar Probe (PSP) and Solar Orbiter missions are designed to make groundbreaking observations of the Sun and interplanetary space within this decade. We show that a particularly interesting in situ observation of an interplanetary coronal mass ejection (ICME) by PSP may arise during close solar flybys (&lt;0.1 au). During these times, the same magnetic flux rope inside an ICME could be observed in situ by PSP twice, by impacting its frontal part as well as its leg. Investigating the odds of this situation, we forecast the ICME rate in solar cycle 25 based on two models for the sunspot number (SSN): (1) the forecast of an expert panel in 2019 (maximum SSN = 115), and (2) a prediction by McIntosh et al. (2020, maximum SSN = 232). We link the SSN to the observed ICME rates in solar cycles 23 and 24 with the Richardson and Cane list and our own ICME catalog, and calculate that between one and seven ICMEs will be observed by PSP at heliocentric distances &lt;0.1 au until 2025, including 1σ uncertainties. We then model the potential flux rope signatures of such a double-crossing event with the semiempirical 3DCORE flux rope model, showing a telltale elevation of the radial magnetic field component BR, and a sign reversal in the component BN normal to the solar equator compared to field rotation in the first encounter. This holds considerable promise to determine the structure of CMEs close to their origin in the solar corona.

Keywords: Ejecta, Space weather, Solar wind, Solar system, Solar physics, Interplanetary magnetic fields, Solar coronal mass ejections, Solar magnetic fields, Solar storm
Binary Fraction Estimation of Main-sequence Stars in 12 Open Clusters: Based on the Homogeneous Data of LAMOST Survey and Gaia DR2. Based on the homogeneous low-resolution spectra data observed by Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the Gaia Data Release 2 (Gaia DR2) photometric data, we chose 12 open clusters (OCs) to study their fundamental parameters and binary fractions (BFs). For each OC, more than 20 cluster members were observed by LAMOST, and some of them were observed multiple times. We used these data to derive precise metallicities of OCs. Combining the metallicities and the Gaia DR2 photometric data, we used the isochrone fitting method to obtain fundamental parameters of these OCs. By fixing metallicity during the fitting, we avoided the effect of degeneracy between the metallicity and reddening. Based on the fundamental parameters, we utilized the synthetic color-magnitude diagram (CMD) method to derive the BFs of main-sequence (MS) stars, the mass functions (MFs) with correction of binaries, and the companion mass ratio distributions. The BFs of observed MS stars in OCs in this paper vary from 29% to 55%. Extrapolating the synthetic CMD to the hydrogen-burning limit, the BFs vary from 13% to 47%. Combining MFs published by previous literature with our results, we found that MFs with correction of binaries were steeper than those without correction by Δα = 0.6 ± 0.16 in the mass range of m ∈ [1M⊙, 2.67M⊙]. We found that the companion mass ratio distribution in OCs of our sample was flat. We also found a significant positive correlation between the BF and density.

Keywords: Observational astronomy, Open star clusters, Binary stars, Stellar dynamics
ALMA Observations of Giant Molecular Clouds in M33. II. Triggered High-mass Star Formation by Multiple Gas Colliding Events at the NGC 604 Complex. We present the results of ALMA observations in 12CO(J = 2 - 1), 13CO(J = 2 - 1), and C18O(J = 2 - 1) lines and 1.3 mm continuum emission toward a massive (∼106 M⊙) giant molecular cloud associated with the giant H II region NGC 604 in one of the nearest spiral galaxies, M33, at an angular resolution of 0"44 × 0"27 (1.8 pc × 1.1 pc). The 12CO and 13CO images show highly complicated molecular structures composed of a lot of filaments and shells whose lengths are 5-20 pc. We found three 1.3 mm continuum sources to be dense clumps at the edges of two shells and also at the intersection of several filaments. We examined the velocity structures of the 12CO(J = 2 - 1) emission in the shells and filaments containing dense clumps, and concluded that expansion of the H II regions cannot explain the formation of such dense cores. Alternatively, we suggest that cloud-cloud collisions induced by an external H I gas flow and the galaxy's rotation compressed the molecular material into dense filaments/shells which are ongoing high-mass star formation sites. We propose that multiple gas converging/colliding events with a velocity of a few tens of kilometers per second are necessary to build up NGC 604, the most significant cluster-forming complex in the Local Group of galaxies.

Keywords: Local Group, Giant molecular clouds, Triangulum Galaxy, Star formation, Interstellar medium, H II regions
Effects of Magnetic Perturbation on Reconnection and Heating in the Solar Corona. The solar corona exhibits unusually high temperatures (∼106 K) compared to the photosphere (∼5800 K). This coronal heating is one of the fundamental problems in solar physics that has yet to be resolved. Magnetic reconnection is thought to play a critical role in driving this enigmatic heating process. We address the interplay between reconnection in the solar corona and the photospheric footpoint motion. The effect of the latter is modeled to generate an external magnetic perturbation that is added to the main coronal field. Resistive magnetohydrodynamics is used where sources and sinks terms due to the perturbation are explicitly obtained in the equations. We set the perturbation to be sinusoidal in space while remaining time independent. The equations are solved using openFOAM. Our results show that magnetic reconnection with perturbation, even with a very small amplitude, leads to (1) more complex formation and evolution of X-points and plasmoids, (2) a transition from slow to fast reconnection rate, (3) a stronger increase of the temperature, and (4) a quicker formation of high-speed jets driving the hot plasma outside the simulation domain with a Mach number that is six times greater compared to the case without perturbation. Moreover, we also find that a magnetic perturbation with shorter wavelength promotes even a faster temporal evolution of the reconnection process than for the longer wavelength. Therefore, the heating and the dynamics of plasma particles in the solar corona are significantly enhanced when the reconnection process is externally disturbed by even a very small perturbation.

Keywords: Magnetohydrodynamics, Solar coronal heating, Solar magnetic reconnection
The μ Tau Association: A 60 Myr Old Coeval Group at 150 pc from the Sun. We present an analysis of the newly identified μ Tau Association (MUTA) of young stars at ≃150 pc from the Sun that is part of the large Cas-Tau structure, coeval and comoving with the α Persei cluster. This association is also located in the vicinity of the Taurus-Auriga star-forming region and the Pleiades association, although it is unrelated to them. We identify more than 500 candidate members of MUTA using Gaia DR2 data and the BANYAN Σ tool, and we determine an age of 62 ± 7 Myr for its population based on an empirical comparison of its color-magnitude diagram sequence with those of other nearby young associations. The MUTA association is related to the Theia 160 group of Kounkel &amp; Covey and corresponds to the e Tau group of Liu et al. It is also part of the Cas-Tau group of Blaauw. As part of this analysis, we introduce an iterative method based on spectral templates to perform an accurate correction of interstellar extinction of Gaia DR2 photometry, needed because of its wide photometric bandpasses. We show that the members of MUTA display an expected increased rate of stellar activity and faster rotation rates compared with older stars, and that literature measurements of the lithium equivalent width of nine G0- to K3-type members are consistent with our age determination. We show that the present-day mass function of MUTA is consistent with other known nearby young associations. We identify WD 0340+103 as a hot, massive white dwarf remnant of a B2 member that left its planetary nebula phase only 270,000 yr ago, posing an independent age constraint of ${60}_{-6}^{+8}$ Myr for MUTA, consistent with our isochrone age. This relatively large collection of comoving young stars near the Sun indicates that more work is required to unveil the full kinematic structure of the complex of young stars surrounding α Persei and Cas-Tau.

Keywords: Brown dwarfs, Stellar kinematics, Astrometry, Proper motions, Low mass stars, Stellar associations
Defining the (Black Hole)-Spheroid Connection with the Discovery of Morphology-dependent Substructure in the M<SUB>BH</SUB>-n<SUB>sph</SUB> and M<SUB>BH</SUB>-R<SUB>e,sph</SUB> Diagrams: New Tests for Advanced Theories and Realistic Simulations. For 123 local galaxies with directly measured black hole masses (MBH), we provide the host spheroid's Sérsic index (nsph), effective half-light radius (Re,sph), and effective surface brightness ( ${\mu }_{{\rm{e}}}$ ), obtained from careful multicomponent decompositions, and we use these to derive the morphology-dependent MBH-nsph and MBH-Re,sph relations. We additionally present the morphology-dependent M*,sph-nsph and M*,sph-Re,sph relations. We explored differences due to early-type galaxies (ETGs) versus late-type galaxies (LTGs), Sérsic versus core-Sérsic galaxies, barred versus non-barred galaxies, and galaxies with and without a stellar disk. We detect two different MBH-nsph relations due to ETGs and LTGs with power-law slopes 3.95 ± 0.34 and 2.85 ± 0.31. We additionally quantified the correlation between MBH and the spheroid's central concentration index, which varies monotonically with the Sérsic index. Furthermore, we observe a single, near-linear M*,sph- ${R}_{{\rm{e}},\mathrm{sph}}^{1.08\pm 0.04}$ relation for ETGs and LTGs, which encompasses both classical and alleged pseudobulges. In contrast, ETGs and LTGs define two distinct MBH-Re,sph relations with ${{\rm{\Delta }}}_{\mathrm{rms}| \mathrm{BH}}\sim 0.60\,\mathrm{dex}$ (cf. ∼0.51 dex for the MBH-σ relation and ∼0.58 dex for the MBH-M*,sph relation), and the ETGs alone define two steeper MBH-Re,sph relations, offset by ∼1 dex in the $\mathrm{log}{M}_{\mathrm{BH}}$ direction, depending on whether they have a disk or not and explaining their similar offset in the MBH-M*,sph diagram. This trend holds using 10%, 50%, or 90% radii. These relations offer pivotal checks for simulations trying to reproduce realistic galaxies, and for theoretical studies investigating the dependence of black hole mass on basic spheroid properties.

Keywords: Supermassive black holes, Black hole physics, Late-type galaxies, Spiral galaxies, Galaxy bulges, Galaxy structure, Galaxy spheroids, Scaling relations, Galaxy evolution, Early-type galaxies
Delivery of Pebbles from the Protoplanetary Disk into Circumplanetary Disks. Small bodies likely existed in the late stage of planet formation either as remnants of the planetesimal formation stage or as fragments of larger planetesimals. Recent studies suggest that they may have played an important role in the formation of regular satellites of giant planets, but their delivery process into the circumplanetary disk has been poorly understood. Using orbital integration that incorporates the gas flow around the planet obtained by hydrodynamic simulation, we examine delivery of small bodies in the protoplanetary disk into circumplanetary disks. We find that large bodies can be captured when they experience strong gas drag near the midplane of the circumplanetary disk, while particles with Stokes number near unity tend to settle toward the midplane of the protoplanetary disk and can be captured near the outer edge of the circumplanetary disk. On the other hand, small particles coupled to the gas can be delivered into the circumplanetary disk with the vertically accreting gas and are captured near the surface of the circumplanetary disk over a wide radial region, if they are sufficiently stirred off the midplane of the protoplanetary disk. However, if the turbulence in the protoplanetary disk is not sufficiently strong, delivery of small particles by such a mechanism would not be efficient. Also, gas depletion in the vicinity of the planet's orbit reduces the efficiency of the delivery. In these cases, larger bodies directly captured by gas drag from the circumplanetary disk would be the major building blocks of regular satellites.

Keywords: Natural satellite formation, Protoplanetary disks, Exoplanet formation, Galilean satellites, Extrasolar gaseous giant planets, Jovian satellites
Stellar Spins in the Open Cluster NGC 2516. Measuring the distribution of stellar spin axis orientations in a coeval group of stars probes the physical processes underlying the stars' formation. In this paper, we use spectrophotometric observations of the open cluster NGC 2516 to determine the degree of spin alignment among its stars. We combine TESS light curves, ground-based spectroscopy from the Gaia-ESO and GALAH surveys, broadband stellar magnitudes from several surveys, and Gaia astrometry to measure 33 stellar inclinations and quantify overall cluster rotation. Our measurements suggest that stellar spins in this cluster are isotropically oriented, while allowing for the possibility that they are moderately aligned. An isotropic distribution of NGC 2516 spins would imply a star-forming environment in which turbulence dominated ordered motion, while a moderately aligned distribution would suggest a more substantial contribution from rotation. We also perform a three-dimensional analysis of the cluster's internal kinematics, finding no significant signatures of overall rotation. Stemming from this analysis, we identify evidence of cluster contraction, suggesting possible ongoing mass segregation in NGC 2516.

Keywords: Open star clusters, Stellar rotation, Star formation, Inclination
Blue Large-amplitude Pulsators: The Possible Surviving Companions of Type Ia Supernovae. The single degenerate (SD) model, one of the leading models for the progenitors of Type Ia supernovae (SNe Ia), predicts that there should be binary companions that survive the supernova explosion, which, in principle, should be detectable in the Galaxy. The discovery of such surviving companions could therefore provide conclusive support for the SD model. Several years ago, a new type of mysterious variable was discovered, the so-called blue large-amplitude pulsators (BLAPs). Here we show that all the properties of BLAPs can be reasonably well reproduced if they are indeed such surviving companions, in contrast to other proposed channels. This suggests that BLAPs could potentially be the long-sought surviving companions of SNe Ia. Our model also predicts a new channel for forming single hot subdwarf stars, consistent with a small group in the present sample of hot subdwarf stars.

Keywords: Supernova remnants, White dwarf stars, Type Ia supernovae, Variable stars
Galactopause Formation and Gas Precipitation during Strong Galactic Outflows. Using X-ray constrained β-models for the radial distribution of gas in the outskirts of galaxies, we analyze the termination of galactic winds and the formation and evolution of halo clouds by thermal instability. At low mass-loss rates ( ${\dot{M}}_{w}$ ) galactic winds are trapped within the halo, but they burst into the intergalactic medium during intermittent strong outflows with ${\dot{M}}_{w}\gt 10\,{M}_{\odot }\,{{\rm{yr}}}^{-1}$ . We develop analytic models of halo clouds as they cool radiatively over condensation timescales ${t}_{{\rm{c}}}\approx {(390\mathrm{Myr})({T}_{6}/{n}_{-4})(Z/{Z}_{\odot })}^{-1}$ for hydrogen number densities ${n}_{{\rm{H}}}\approx ({10}^{-4}\,{\mathrm{cm}}^{-3}){n}_{-4}$ , gas temperatures T ≈ (106 K)T6, and metallicities (Z/Z⊙). Halo gas can form kiloparsec-scale clouds out to galactocentric distances r ≈ 30-65 kpc, where efficient radiative cooling from 106 K down to T ≈ 104-5 K occurs at Z ≥ 0.3 Z⊙ on timescales less than 1 Gyr. After condensing to column densities NH ≥ 4 × 1016 cm-2, these clouds lose hydrostatic pressure support and fall inward on dynamical timescales of ∼200 Myr. Our baseline analysis will be followed by numerical calculations to understand the governing principles of halo cloud formation and transport of gas to the galactic disk.

Keywords: Galactic winds, High-velocity clouds, Interstellar medium
Transport, Destruction, and Growth of Pebbles in the Gas Envelope of a Protoplanet. We analyze the size evolution of pebbles accreted into the gaseous envelope of a protoplanet growing in a protoplanetary disk, taking into account collisions driven by the relative sedimentation speed as well as the convective gas motion. Using a simple estimate of the convective gas speed based on the pebble accretion luminosity, we find that the speed of the convective gas is higher than the sedimentation speed for all particles smaller than 1 mm. This implies that both pebbles and pebble fragments are strongly affected by the convective gas motion and will be transported by large-scale convection cells both toward and away from the protoplanet's surface. We present a simple scheme for evolving the characteristic size of the pebbles, taking into account the effects of erosion, mass transfer, and fragmentation. Including the downwards motion of convective cells for the transport of pebbles with an initial radius of 1 mm, we find pebble sizes between 100 μm and 1 mm near the surface of the protoplanet. These sizes are generally amenable to accretion at the base of the convection flow. Small protoplanets far from the star (&gt;30 au) nevertheless erode their pebbles to sizes below 10 μm; future hydrodynamical simulations will be needed to determine whether such small fragments can detach from the convection flow and become accreted by the protoplanet.

Keywords: Planetary system formation, Exoplanet formation
Ram Pressure Stripping of HI-rich Galaxies Infalling into Massive Clusters. We estimate the strength of ram pressure stripping (RPS) for HI-rich galaxies in X-ray detected clusters. We find that galaxies under stronger RPS tend to show more significantly reduced total HI mass and enhanced central SFR when compared to control galaxies in the field that have similar stellar mass, stellar surface density and integral star formation rate. Galaxies under strong or weak RPS account for ∼40% of the HI-rich population at R200, and even beyond R200 in the most massive clusters. Our results imply the important role of RPS as a channel of environmental processing far before the galaxies reach the core region of clusters.

Keywords: Galaxy clusters, Interstellar atomic gas, Galaxy environments, Star formation, Galaxy evolution
Full-sky Cosmic Microwave Background Foreground Cleaning Using Machine Learning. In order to extract cosmological information from observations of the millimeter and submillimeter sky, foreground components must first be removed to produce an estimate of the cosmic microwave background (CMB). We developed a machine-learning approach for doing so for full-sky temperature maps of the millimeter and submillimeter sky. We constructed a Bayesian spherical convolutional neural network architecture to produce a model that captures both spectral and morphological aspects of the foregrounds. Additionally, the model outputs a per-pixel error estimate that incorporates both statistical and model uncertainties. The model was then trained using simulations that incorporated knowledge of these foreground components that was available at the time of the launch of the Planck satellite. On simulated maps, the CMB is recovered with a mean absolute difference of &lt;4 μK over the full sky after masking map pixels with a predicted standard error of &gt;50 μK; the angular power spectrum is also accurately recovered. Once validated with the simulations, this model was applied to Planck temperature observations from its 70 GHz through 857 GHz channels to produce a foreground-cleaned CMB map at a HEALPIX map resolution of NSIDE = 512. Furthermore, we demonstrate the utility of the technique for evaluating how well different simulations match observations, particularly in regard to the modeling of thermal dust.

Keywords: Observational cosmology, Cosmic microwave background radiation, Convolutional neural networks
Non-Markovian Pitch-angle Scattering as the Origin of Particle Superdiffusion Parallel to the Magnetic Field. We develop a theoretical model for particle superdiffusive transport parallel to the average magnetic field, due to the pitch-angle scattering times having a non-Markovian, power-law probability distribution. We show that a non-Markovian Fokker-Planck equation can be derived, where the traditional time derivative is changed for a fractional time derivative. By solving the fractional Fokker-Planck equation, with the time-dependent part having solutions that are expressed by the Mittag-Leffler functions, it is found that an initial pitch-angle distribution slowly decays toward isotropy. This leads to a parallel velocity autocorrelation function that also has a slow power-law decay in time, thus implying superdiffusive transport in the direction parallel to the background magnetic field. In this framework, we derive for the first time the anomalous diffusion coefficient as a function of physical parameters like the background magnetic field, the resonant turbulence level, and the particle speed.

Keywords: Interplanetary turbulence, Solar energetic particles, Astrophysical processes, Particle astrophysics, Cosmic rays