Sazuna/UAT_keywords huggingface dataset:
Solar Vortex Tubes. II. On the Origin of Magnetic Vortices. The solar atmosphere presents a wealth of dynamics due to a constant interplay between the plasma flows and magnetic fields. Twisted flux tubes are an essential magnetic structure, believed to be driven by the rotational surface's motions and linked to plasma heating, jets, and eruptive phenomena. Despite extensive investigations, twisted magnetic flux tubes lack a proper mathematical definition, precluding their automatic detection. This work addresses this issue by defining them as magnetic vortices and introduces a formal definition that is based on a recently developed magnetic vortex detection technique, the integrated averaged current deviation method. We applied this method and a kinetic vortex identification technique to realistic magnetoconvection simulations obtained from the MURaM code. The preferential site for these two types of vortices is the intergranular downflow, but while the magnetic vortices are found mostly in the small areas where plasma-β &gt; 1, the rotational flow structures (the kinetic vortices), were detected in locations where plasma-β &lt; 1. The magnetic vortices locally concentrate the magnetic field's vertical components and current, lasting, on average, around a minute. Two types of magnetic vortices are introduced based on their magnetic-to-kinetic energy ratio. For the first type, the magnetic energy prevails, and the magnetic vortices are mostly vertical. The second type of magnetic vortex presents distinct shapes and a lower magnetic-to-kinetic energy ratio. We have found that magnetic vortices may appear if two conditions are simultaneously present: (i) shear flow and (ii) plasma-β &gt; 1. The presence of rotational motion is not necessary.

Keywords: Solar atmospheric motions, Solar photosphere, Solar magnetic fields, Magnetohydrodynamics
Study of Temporal and Spectral variability for Blazar PKS 1830-211 with Multiwavelength Data. A study of the gravitationally lensed blazar PKS 1830-211 was carried out using multi-wave band data collected by Fermi-LAT, Swift-XRT, and Swift-UVOT telescopes between MJD 58400 to MJD 58800 (2018 October 9-2019 November 13). Flaring states were identified by analyzing the γ-ray light curve. Simultaneous multi-wave band spectral energy distributions (SEDs) were obtained for these flaring periods. A cross-correlation analysis of the multi-wave band data was carried out, which suggested a common origin of the γ-ray and X-ray emission. The broadband emission mechanism was studied by modeling the SED using a leptonic model. Physical parameters of the blazar were estimated from the broadband SED modeling. The blazar PKS 1830-211 is gravitationally lensed by at least two galaxies and has been extensively studied in the literature because of this property. The self-correlation of the γ-ray light curve was studied to identify the signature of lensing, but no conclusive evidence of correlation was found at the expected time delay of 26 days.

Keywords: Blazars, Active galactic nuclei
Relaxation in a Fuzzy Dark Matter Halo. II. Self-consistent Kinetic Equations. Fuzzy dark matter (FDM) is composed of ultra-light bosons having a de Broglie wavelength that is comparable to the size of the stellar component of galaxies at typical galactic velocities. FDM behaves like cold dark matter on large scales. However, on the scale of the de Broglie wavelength, an FDM halo exhibits density fluctuations that lead to relaxation, a process similar to the two-body relaxation that occurs in classical gravitational N-body systems and is described by the Fokker-Planck equation. We derive the FDM analog of that kinetic equation, which describes the evolution of the velocity distribution in a spatially homogeneous FDM halo. We show that the evolution of the velocity distribution predicted by our kinetic equation matches numerical solutions of the coupled Schrödinger-Poisson equations. We also determine the dielectric function and the dispersion relation for linear waves in an FDM halo.

Keywords: Galaxy kinematics, Dark matter
Self-consistent 3D Supernova Models From -7 Minutes to +7 s: A 1-bethe Explosion of a 19 M<SUB>⊙</SUB> Progenitor. To date, modern three-dimensional (3D) supernova (SN) simulations have not demonstrated that explosion energies of 1051 erg (=1 bethe=1 B) or more are possible for neutrino-driven SNe of non/slow-rotating M &lt; 20 M⊙ progenitors. We present the first such model, considering a nonrotating, solar-metallicity 18.88 M⊙ progenitor, whose final 7 minutes of convective oxygen-shell burning were simulated in 3D and showed a violent oxygen-neon shell merger prior to collapse. A large set of 3D SN models was computed with the PROMETHEUS-VERTEX code, whose improved convergence of the two-moment equations with Boltzmann closure allows now to fully exploit the implicit neutrino-transport treatment. Nuclear burning is treated with a 23-species network. We vary the angular grid resolution and consider different nuclear equations of state and muon formation in the proto-neutron star (PNS), which requires six-species transport with coupling of all neutrino flavors across all energy-momentum groups. Elaborate neutrino transport was applied until ~2 s after bounce. In one case, the simulation was continued to &gt;7 s with an approximate treatment of neutrino effects that allows for seamless continuation without transients. A spherically symmetric neutrino-driven wind does not develop. Instead, accretion downflows to the PNS and outflows of neutrino-heated matter establish a monotonic rise of the explosion energy until ~7 s post-bounce, when the outgoing shock reaches ~50,000 km and enters the He layer. The converged value of the explosion energy at infinity (with overburden subtracted) is ~1 B and the ejected 56Ni mass ≲0.087 M⊙, both within a few 10% of the SN 1987A values. The final NS mass and kick are ~1.65 M⊙ and &gt;450 km s-1, respectively.

Keywords: Core-collapse supernovae
Sensitivity Study of r-process Abundances to Nuclear Masses. The impact of nuclear mass uncertainties on the r-process abundances has been systematically studied with the classical r-process model by varying the mass of every individual nucleus in the range of ±0.1 to ±3.0 MeV based on six different mass models. A new quantitative relation between the uncertainties of r-process abundances and those of the nuclear masses is extracted, i.e., a mass uncertainty of ±0.5 MeV would lead to an abundance uncertainty of a factor around 2.5. It is found that this conclusion holds true for various mass models.

Keywords: Solar abundances, R-process, Nucleosynthesis
Numerical Research on the Effect of the Initial Parameters of a CME Flux-rope Model on Simulation Results. II. Different Locations of Observers. In numerical studies of the initiation and propagation of coronal mass ejections (CMEs), it has been proven that the shape, size, and plasma parameters of CMEs could significantly affect simulation results and subsequent space weather predictions. In our previous research, we proposed a new way to initiate a CME based on the graduated cylindrical shell model, and studied the effect of different initial parameters of CMEs on the simulation results when the observer is aligned with the initial propagation direction of the CME. In this paper, we investigate the influence of the different initial parameters of CMEs on simulation results at the observational points with different longitudes and latitudes. Our results indicate that as long as the initial mass of the CME remains unchanged, the initial geometric thickness will have a different influence in the latitudinal and longitudinal directions. The deflection of the CMEs always occurs in both latitudinal and longitudinal directions, when the CMEs interact with the background solar wind structures, such as the corotating interaction region, in the heliosphere.

Keywords: Space weather, Solar wind, Solar coronal mass ejections, Magnetohydrodynamical simulations
Magnetically Arrested Disks in Quiescent Black Hole Binaries: Formation Scenario, Observable Signatures, and Potential PeVatrons. We propose magnetically arrested disks (MADs) in quiescent (low-luminosity) black hole (BH) binaries as the origin of multiwavelength emission, and argue that this class of sources can dominate the cosmic-ray spectrum around the knee. X-ray luminosities of Galactic BH binaries in the quiescent state are far below the Eddington luminosity, and thus radiatively inefficient accretion flows (RIAFs) are formed in the inner region. Strong thermal and turbulent pressures in RIAFs produce outflows, which can create large-scale poloidal magnetic fields. These fields are carried to the vicinity of the BH by the rapid inflow motion, forming a MAD. Inside the MAD, nonthermal protons and electrons are naturally accelerated by magnetic reconnections or stochastic acceleration by turbulence. Both thermal and nonthermal electrons emit broadband photons via synchrotron emission, which are broadly consistent with the optical and X-ray data of the quiescent BH X-ray binaries. Moreover, protons are accelerated up to PeV energies and diffusively escape from these MADs, which can account for the cosmic-ray intensity around the knee energy.

Keywords: Accretion, Stellar mass black holes, Non-thermal radiation sources, Cosmic ray sources, Low-mass x-ray binary stars
Spectroscopic Confirmation of Two Extremely Massive Protoclusters, BOSS1244 and BOSS1542, at z = 2.24. We present spectroscopic confirmation of two new massive galaxy protoclusters at z = 2.24 ± 0.02, BOSS1244 and BOSS1542, traced by groups of Coherently Strong Lyα Absorption (CoSLA) systems imprinted in the absorption spectra of a number of quasars from the Sloan Digital Sky Survey III (SDSS III) and identified as overdensities of narrowband-selected Hα emitters (HAEs). Using Multiple Mirror Telescope/Magellan Infrared Spectrograph and Large Binocular Telescope/LUCI near-infrared (NIR) spectroscopy, we confirm 46 and 36 HAEs in the BOSS1244 (~55 arcmin2) and BOSS1542 (~61 arcmin2) fields, respectively. BOSS1244 displays a southwest (SW) component at z = 2.230 ± 0.002 and another northeast (NE) component at z = 2.246 ± 0.001 with the line-of-sight velocity dispersions of 405 ± 202 km s-1 and 377 ± 99 km s-1, respectively. Interestingly, we find that the SW region of BOSS1244 contains two substructures in redshift space, likely merging to form a larger system. In contrast, BOSS1542 exhibits an extended filamentary structure with a low-velocity dispersion of 247 ± 32 km s-1 at z = 2.241 ± 0.001, providing a direct confirmation of a large-scale cosmic web in the early universe. The galaxy overdensities δg on the scale of 15 cMpc are 22.9 ± 4.9, 10.9 ± 2.5, and 20.5 ± 3.9 for the BOSS1244 SW, BOSS1244 NE, and BOSS1542 filament, respectively. They are the most overdense galaxy protoclusters (δg &gt; 20) discovered to date at z &gt; 2. These systems are expected to become virialized at z ~ 0 with a total mass of MSW = (1.59 ± 0.20) × 1015M⊙, MNE = (0.83 ± 0.11) × 1015 M⊙ and Mfilament = (1.42 ± 0.18) × 1015 M⊙, respectively. Our results suggest that the dense substructures of BOSS1244 and BOSS1542 will eventually evolve into the Coma-type galaxy clusters or even larger. Together with BOSS1441 described in Cai et al., these extremely massive overdensities at z = 2-3 exhibit different morphologies, indicating that they are in different assembly stages in the formation of early galaxy clusters. Furthermore, there are two quasar pairs in BOSS1441 and one quasar pair in BOSS1244 and BOSS1542; CoSLAs detected in these quasar pairs can be used to trace the extremely massive large-scale structures of the universe.

Keywords: Galaxy formation, Large-scale structure of the universe, Protoclusters, Galaxy evolution, High-redshift galaxies
Probing Cosmic Reionization and Molecular Gas Growth with TIME. Line intensity mapping (LIM) provides a unique and powerful means to probe cosmic structures by measuring the aggregate line emission from all galaxies across redshift. The method is complementary to conventional galaxy redshift surveys that are object based and demand exquisite point-source sensitivity. The Tomographic Ionized-carbon Mapping Experiment (TIME) will measure the star formation rate during cosmic reionization by observing the redshifted [C II] 158 μm line (6 ≲ z ≲ 9) in the LIM regime. TIME will simultaneously study the abundance of molecular gas during the era of peak star formation by observing the rotational CO lines emitted by galaxies at 0.5 ≲ z ≲ 2. We present the modeling framework that predicts the constraining power of TIME on a number of observables, including the line luminosity function and the auto- and cross-correlation power spectra, including synergies with external galaxy tracers. Based on an optimized survey strategy and fiducial model parameters informed by existing observations, we forecast constraints on physical quantities relevant to reionization and galaxy evolution, such as the escape fraction of ionizing photons during reionization, the faint-end slope of the galaxy luminosity function at high redshift, and the cosmic molecular gas density at cosmic noon. We discuss how these constraints can advance our understanding of cosmological galaxy evolution at the two distinct cosmic epochs for TIME, starting in 2021, and how they could be improved in future phases of the experiment.

Keywords: Molecular gas, Large-scale structure of the universe, Observational cosmology, Interstellar medium, Reionization, High-redshift galaxies
The Carnegie Chicago Hubble Program X: Tip of the Red Giant Branch Distances to NGC 5643 and NGC 1404. The primary goal of the Carnegie Chicago Hubble Program (CCHP) is to calibrate the zero-point of the Type Ia supernova (SN Ia) Hubble Diagram through the use of Population II standard candles. So far, the CCHP has measured direct distances to 11 SNe Ia, and here we increase that number to 15 with two new Tip of the Red Giant Branch (TRGB) distances measured to NGC 5643 and NGC 1404. We present resolved, point-source photometry from new Hubble Space Telescope imaging of these two galaxies in the F814W and F606W bandpasses. From each galaxy's stellar halo, we construct an F814W-band luminosity function in which we detect an unambiguous edge feature identified as the TRGB. For NGC 5643, we find μ0 = 30.48 ± 0.03(stat) ± 0.07(sys) mag, and for NGC 1404 we find μ0 = 31.36 ± 0.04(stat) ± 0.05(sys) mag. From a preliminary consideration of the SNe Ia in these galaxies, we find increased confidence in the results presented in Paper VIII. The high precision of our TRGB distances enables a significant measurement of the 3D displacement between the Fornax cluster galaxies NGC 1404 and NGC 1316 (Fornax A) equal to ${1.50}_{-0.39}^{+0.25}$ Mpc, which we show is in agreement with independent constraints found in the literature.

Keywords: Galaxy distances, Standard candles, Galaxy stellar content, HST photometry, Hubble constant, Galaxy stellar halos, Giant elliptical galaxies, Seyfert galaxies, Population II stars
SDSS-IV MaNGA: Refining Strong Line Diagnostic Classifications Using Spatially Resolved Gas Dynamics. We use the statistical power of the MaNGA integral-field spectroscopic galaxy survey to improve the definition of strong line diagnostic boundaries used to classify gas ionization properties in galaxies. We detect line emission from 3.6 million spaxels distributed across 7400 individual galaxies spanning a wide range of stellar masses, star formation rates, and morphological types, and find that the gas-phase velocity dispersion σHα correlates strongly with traditional optical emission-line ratios such as [S II]/Hα, [N II]/Hα, [O I]/Hα, and [O III]/Hβ. Spaxels whose line ratios are most consistent with ionization by galactic H II regions exhibit a narrow range of dynamically cold line-of-sight velocity distributions (LOSVDs) peaked around 25 km s-1 corresponding to a galactic thin disk, while those consistent with ionization by active galactic nuclei (AGNs) and low-ionization emission-line regions (LI(N)ERs) have significantly broader LOSVDs extending to 200 km s-1. Star-forming, AGN, and LI(N)ER regions are additionally well separated from each other in terms of their stellar velocity dispersion, stellar population age, Hα equivalent width, and typical radius within a given galaxy. We use our observations to revise the traditional emission-line diagnostic classifications so that they reliably identify distinct dynamical samples both in two-dimensional representations of the diagnostic line ratio space and in a multidimensional space that accounts for the complex folding of the star-forming model surface. By comparing the MaNGA observations to the SDSS single-fiber galaxy sample, we note that the latter is systematically biased against young, low-metallicity star-forming regions that lie outside of the 3″ fiber footprint.

Keywords: Galaxy kinematics
Identifying Acoustic Wave Sources on the Sun. I. Two-dimensional Waves in a Simulated Photosphere. The solar acoustic oscillations are likely stochastically excited by convective dynamics in the solar photosphere, though few direct observations of individual source events have been made and their detailed characteristics are still unknown. Wave source identification requires measurements that can reliably discriminate the local wave signal from the background convective motions and resonant modal power. This is quite challenging as these noise contributions have amplitudes several orders of magnitude greater than the sources and the propagating wave fields they induce. In this paper, we employ a high-temporal-frequency filter to identify sites of acoustic emission in a radiative magnetohydrodynamic simulation. The properties of the filter were determined from a convolutional neural network trained to identify the two-dimensional acoustic Green's function response of the atmosphere, but once defined, it can be directly applied to an image time series to extract the signal of local wave excitation, bypassing the need for the original neural network. Using the filter developed, we have uncovered previously unknown properties of the acoustic emission process. In the simulation, acoustic events are found to be clustered at mesogranular scales, with peak emission quite deep, about 500 km below the photosphere, and sites of very strong emission can result from the interaction of two supersonic downflows that merge at that depth. We suggest that the method developed, when applied to high-resolution high-cadence observations, such as those forthcoming with the Daniel K. Inouye Solar Telescope, will have important applications in chromospheric wave studies and may lead to new investigations in high-resolution local helioseismology.

Keywords: Solar photosphere, Helioseismology, The Sun, Solar physics, Solar granulation, Solar oscillations
New Observational Constraints on the Winds of M dwarf Stars. High-resolution UV spectra of stellar H I Lyα lines from the Hubble Space Telescope (HST) provide observational constraints on the winds of coronal main-sequence stars, thanks to an astrospheric absorption signature created by the interaction between the stellar winds and the interstellar medium. We report the results of a new HST survey of M dwarf stars, yielding six new detections of astrospheric absorption. We estimate mass-loss rates for these detections and upper limits for nondetections. These new constraints allow us to characterize the nature of M dwarf winds and their dependence on coronal activity for the first time. For a clear majority of the M dwarfs, we find winds that are weaker than or comparable in strength to that of the Sun, i.e., $\dot{M}\leqslant 1\,{\dot{M}}_{\odot }$ . However, two of the M dwarfs have much stronger winds: YZ CMi (M4 Ve; $\dot{M}=30\,{\dot{M}}_{\odot }$ ) and GJ 15AB (M2 V+M3.5 V; $\dot{M}=10\,{\dot{M}}_{\odot }$ ). Even these winds are much weaker than expectations if the solar relation between flare energy and coronal mass ejection (CME) mass extended to M dwarfs. Thus, the solar flare/CME relation does not appear to apply to M dwarfs, with important ramifications for the habitability of exoplanets around M dwarfs. There is evidence for some increase in $\dot{M}$ with coronal activity as quantified by X-ray flux, but with much scatter. One or more other factors must be involved in determining wind strength besides spectral type and coronal activity, with magnetic topology being one clear possibility. * Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-15326.

Keywords: Astrospheres, Stellar phenomena, Ultraviolet astronomy, Stellar winds, Stellar coronae
Flare-forecasting Algorithms Based on High-gradient Polarity Inversion Lines in Active Regions. Solar flares emanate from solar active regions hosting complex and strong bipolar magnetic fluxes. Estimating the probability of an active region to flare and defining reliable precursors of intense flares are extremely challenging tasks in the space weather field. In this work, we focus on two metrics as flare precursors, the unsigned flux R, tested on Michelson Doppler Imager/Solar and Heliospheric Observatory data, one of the most used parameters for flare-forecasting applications, and a novel topological parameter D, representing the complexity of a solar active region. In greater detail, we propose an algorithm for the computation of the R value, which exploits the higher spatial resolution of Helioseismic Magnetic Imager maps. This algorithm leads to a differently computed R value, whose functionality is tested on a set of solar cycle 24 flares. Furthermore, we introduce a topological parameter based on the automatic recognition of magnetic polarity inversion lines in identified active regions and are able to evaluate its magnetic topological complexity. We use both a heuristic approach and a supervised machine-learning method to validate the effectiveness of these two descriptors to predict the occurrence of X- or M-class flares in a given solar active region during the following 24 hr period. Our feature ranking analysis shows that both parameters play a significant role in prediction performances. Moreover, the analysis demonstrates that the new topological parameter D is the only one, among 173 overall predictors, that is always present for all test subsets and is systematically ranked within the top 10 positions in all tests concerning the computation of the weights with which each predictor impacts the flare forecasting.

Keywords: Solar active region magnetic fields, Solar flares, Solar physics, Solar active regions, Solar activity