Sazuna/UAT_keywords huggingface dataset:
Data-driven MHD Simulation of Successive Solar Plasma Eruptions. Solar flares and plasma eruptions are sudden releases of magnetic energy stored in the plasma atmosphere. To understand the physical mechanisms governing their occurrences, three-dimensional magnetic fields from the photosphere up to the corona must be studied. The solar photospheric magnetic fields are observable, whereas the coronal magnetic fields cannot be measured. One method for inferring coronal magnetic fields is performing data-driven simulations, which involves time-series observational data of the photospheric magnetic fields with the bottom boundary of magnetohydrodynamic simulations. We developed a data-driven method in which temporal evolutions of the observational vector magnetic field can be reproduced at the bottom boundary in the simulation by introducing an inverted velocity field. This velocity field is obtained by inversely solving the induction equation and applying an appropriate gauge transformation. Using this method, we performed a data-driven simulation of successive small eruptions observed by the Solar Dynamics Observatory and the Solar Magnetic Activity Telescope in 2017 November. The simulation well reproduced the converging motion between opposite-polarity magnetic patches, demonstrating successive formation and eruptions of helical flux ropes.

Keywords: Computational astronomy, Solar photosphere, Solar prominences, Computational methods, Solar filaments, Solar corona, Solar filament eruptions
Constraints on Nuclear Saturation Properties from Terrestrial Experiments and Astrophysical Observations of Neutron Stars. Taking into account the terrestrial experiments and the recent astrophysical observations of neutron stars and gravitational-wave signals, we impose restrictions on the equation of state (EoS) for isospin-asymmetric nuclear matter. Using the relativistic mean-field model with SU(3) flavor symmetry, we investigate the impacts of effective nucleon mass, nuclear incompressibility, and slope parameter of nuclear symmetry energy on the nuclear and neutron star properties. It is found that the astrophysical information of massive neutron stars and tidal deformabilities, as well as the nuclear experimental data, plays an important role to restrict the EoS for neutron stars. In particular, the softness of the nuclear EoS due to the existence of hyperons in the core gives stringent constraints on those physical quantities. Furthermore, it is possible to put limits on the curvature parameter of nuclear symmetry energy by means of nuclear and astrophysical calculations.

Keywords: Neutron stars, Nuclear astrophysics, Nuclear physics
Origin of Weak Mg II and Higher-ionization Absorption Lines in Outflows from Intermediate-redshift Dwarf Galaxies. Observations at intermediate redshifts reveal the presence of numerous compact, weak Mg II absorbers with near to supersolar metallicities, often surrounded by extended regions that produce C IV and/or O VI absorption, in the circumgalactic medium at large impact parameters from luminous galaxies. Their origin and nature remain unclear. We hypothesize that undetected satellite dwarf galaxies are responsible for producing some of these weak Mg II absorbers. We test our hypothesis using gas dynamical simulations of galactic outflows from a dwarf galaxy with a halo mass of 5 × 109 M⊙, as might be falling into a larger L* halo at z = 2. We find that thin, filamentary, weak Mg II absorbers (≲100 pc) are produced in two stages: (1) when shocked core-collapse supernova (SN II)-enriched gas descending in a galactic fountain gets shock compressed by upward flows driven by subsequent SN II and cools (phase 1) and, later, (2) during an outflow driven by Type Ia supernovae that shocks and sweeps up pervasive SN II-enriched gas, which then cools (phase 2). The Mg II absorbers in our simulations are continuously generated by shocks and cooling with moderate metallicity ∼0.1-0.2 Z⊙ but low column density &lt;1012 cm-2. They are also surrounded by larger (0.5-1 kpc) C IV absorbers that seem to survive longer. Larger-scale (&gt;1 kpc) C IV and O VI clouds are also produced in both expanding and shocked SN II-enriched gas. Observable ion distributions from our models appear well converged at our standard resolution (12.8 pc). Our simulation highlights the possibility of dwarf galactic outflows producing highly enriched multiphase gas.

Keywords: Galactic winds, Starburst galaxies, Metal line absorbers, Dwarf galaxies, Circumgalactic medium
The Large-scale Magnetic Field Advected in the Corona of a Thin Accretion Disk. Large-scale magnetic field is believed to play a key role in launching and collimating jets/outflows. It was found that advection of the external field by a geometrically thin disk is rather inefficient, while the external weak field may be dragged inwards by fast radially moving tenuous and/or hot gas above the thin disk. We investigate the field advection in a thin (cold) accretion disk covered with hot corona, in which turbulence is responsible for the angular momentum transfer of the gas in the disk and corona. The radial velocity of the gas in the corona is significantly higher than that in the thin disk. Our calculations show that the external magnetic flux is efficiently transported inwards by the corona, and the field line is strongly inclined toward the disk surface, which helps to launch outflows. The field configurations are consistent with those observed in the numerical simulations. The strength of the field is substantially enhanced in the inner region of the disk (usually several orders of magnitude higher than the external field strength), which is able to drive a fraction of gas in the corona into outflows. This mechanism may be useful in explaining the observational features in X-ray binaries and active galactic nuclei. Our results may help in understanding the physics of the magnetohydrodynamic simulations.

Keywords: Accretion, Galaxy accretion disks, Magnetic fields, Galaxy jets
Spectroscopic Monitoring of the Candidate Tidal Disruption Event in F01004-2237. We present results of spectroscopic monitoring observations of the ultraluminous infrared galaxy F01004-2237. This galaxy was observed to undergo changes in its optical spectrum, detected by comparing a spectrum from 2015 with one from 2000. These changes were coincident with photometric brightening. The main changes detected in the optical spectrum are enhanced He II λ4686 emission and the appearance of He I λ3898,λ5876 emission lines. The favored interpretation of these changes was that of a tidal disruption event (TDE) happening in 2010. However, subsequent work suggested that these changes are caused by another hitherto unknown effect related to variations in the accretion rate in the active galactic nucleus (AGN). Our optical spectroscopic monitoring observations show that the evolution of the He lines is in line with the evolution seen in TDEs and opposite of what is observed from reverberation-mapping studies of AGNs, renewing the discussion of the interpretation of the flare as a TDE.

Keywords: High energy astrophysics, Tidal disruption, Transient sources, Active galactic nuclei, Ultraluminous infrared galaxies
Energetic Proton Propagation and Acceleration Simulated for the Bastille Day Event of 2000 July 14. This work presents results from simulations of the 2000 July 14 ("Bastille Day") solar proton event. We used the Energetic Particle Radiation Environment Model (EPREM) and the CORona-HELiosphere (CORHEL) software suite within the SPE Threat Assessment Tool (STAT) framework to model proton acceleration to GeV energies due to the passage of a CME through the low solar corona, and we compared the model results to GOES-08 observations. The coupled simulation models particle acceleration from 1 to 20 R☉, after which it models only particle transport. The simulation roughly reproduces the peak event fluxes and the timing and spatial location of the energetic particle event. While peak fluxes and overall variation within the first few hours of the simulation agree well with observations, the modeled CME moves beyond the inner simulation boundary after several hours. The model therefore accurately describes the acceleration processes in the low corona and resolves the sites of most rapid acceleration close to the Sun. Plots of integral flux envelopes from multiple simulated observers near Earth further improve the comparison to observations and increase potential for predicting solar particle events. Broken power-law fits to fluence spectra agree with diffusive acceleration theory over the low energy range. Over the high energy range, they demonstrate the variability in acceleration rate and mirror the interevent variability observed in solar cycle 23 ground-level enhancements. We discuss ways to improve STAT predictions, including using corrected GOES energy bins and computing fits to the seed spectrum. This paper demonstrates a predictive tool for simulating low-coronal solar energetic particle acceleration.

Keywords: Solar energetic particles, Solar storm, Solar activity, Solar coronal mass ejections
Asymmetrical Mass Ejection from Proto-white Dwarfs and the Formation of Eccentric Millisecond Pulsar Binaries. Binary millisecond pulsars (MSPs) are believed to have descended from low-mass X-ray binaries (LMXBs), which have experienced substantial mass transfer and tidal circularization. Therefore, they should have very circular orbits. However, the discovery of several eccentric binary MSPs (with eccentricity e ∼ 0.01-0.1) challenges this standard picture. Three models have been proposed thus far based on accretion-induced collapse of massive white dwarfs (WDs), neutron star-strange star transition, and formation of circumbinary disks. All of them are subject to various uncertainties and are not entirely consistent with observations. Here, we propose an alternative model that takes into account the influence of thermonuclear flashes on proto-WDs. We assume that the flashes lead to asymmetrical mass ejection, which imparts a mild kick to the proto-WDs. By simulating orbital changes of binary MSPs with multiple shell flashes, we show that it is possible to reproduce the observed eccentricities, provided that the kick velocities are around a few km s-1.

Keywords: White dwarf stars, Binary pulsars, Millisecond pulsars
Consequences for the Scalar Field Dark Matter Model from the McGaugh Observed-baryon Acceleration Correlation. Although the standard cosmological model, the so-called Λ cold dark matter (ΛCDM), appears to fit well observations at the cosmological level, it is well known that it possesses several inconsistencies at the galactic scales. In order to address the problems of the ΛCDM on a small scale, some alternative models have been proposed. Among the most popular candidates, the proposal that dark matter in the universe is made of ultralight bosons is a strong candidate today. For this work, we study through an analytical approach the consequences arising from comparing the Spitzer Photometry and Accurate Rotation Curves catalog observed-baryon acceleration correlation with the scalar field dark matter model. We carry out such analysis either considering the features of galactic halos extracted from structure-formation simulations or considering the existence of other non-dark-matter elements in the whole system (such as baryons or a supermassive black hole). Specifically, we address a recent claim that the model is not capable of reproducing a constant surface density in the core, in contrast to what observations suggest for a host of galaxies with different sizes and morphologies. In this direction, we show that this discrepancy can be alleviated once the contributions of non-dark-matter constituents in the whole galactic system are taken into account. Additionally, we find that a mass of m ≃ 1.41 × 10-22 eV/c2 is capable of reproducing all of our findings and correctly adjusting the rotation curves coming from the Milky Way galaxy.

Keywords: Milky Way dark matter halo
On the Origin of Hard X-Ray Emissions from the Behind-the-limb Flare on 2014 September 1. The origin of hard X-rays and γ-rays emitted from the solar atmosphere during occulted solar flares is still debated. The hard X-ray emissions could come from flaring loop tops rising above the limb or coronal mass ejection shock waves, two by-products of energetic solar storms. For the shock scenario to work, accelerated particles must be released on magnetic field lines rooted on the visible disk and precipitate. We present a new Monte Carlo code that computes particle acceleration at shocks propagating along large coronal magnetic loops. A first implementation of the model is carried out for the 2014 September 1 event, and the modeled electron spectra are compared with those inferred from Fermi Gamma-ray Burst Monitor (GBM) measurements. When particle diffusion processes are invoked, our model can reproduce the hard electron spectra measured by GBM nearly 10 minutes after the estimated on-disk hard X-rays appear to have ceased from the flare site.

Keywords: Solar coronal mass ejection shocks, Solar particle emission, Solar x-ray emission, Solar electromagnetic emission
Supervirial Temperature or Neon Overabundance? Suzaku Observations of the Milky Way Circumgalactic Medium. We analyzed Suzaku and Chandra observations of the soft diffuse X-ray background toward four sight lines with the goal of characterizing the X-ray emission from the Milky Way circumgalactic medium (CGM). We identified two thermal components of the CGM, one at a uniform temperature of kT = 0.176 ± 0.008 keV and the other at temperatures in the range kT = 0.65-0.90 keV. The uniform lower-temperature component is consistent with the Galaxy's virial temperature (∼106 K). The temperatures of the hotter components are similar to that recently discovered (∼107 K) in the sight line to blazar 1ES 1553+113, passing close to the Fermi bubble. Alternatively, the spectra can be described by just one lower-temperature component with supersolar neon abundance, once again similar to that found in the 1ES 1553+113 sight line. The additional hot component or the overabundance of Ne is required at a significance of &gt;4σ, but we cannot distinguish between the two possibilities. These results show that the supervirial temperature gas or an enhanced Ne abundance in the warm-hot gas in the CGM is widespread, and these are not necessarily related to the Fermi bubble.

Keywords: Circumgalactic medium
The Evolution of the IR Luminosity Function and Dust-obscured Star Formation over the Past 13 Billion Years. We present the first results from the Mapping Obscuration to Reionization with ALMA (MORA) survey, the largest Atacama Large Millimeter/submillimeter Array (ALMA) blank-field contiguous survey to date (184 arcmin2) and the only at 2 mm to search for dusty star-forming galaxies (DSFGs). We use the 13 sources detected above 5σ to estimate the first ALMA galaxy number counts at this wavelength. These number counts are then combined with the state-of-the-art galaxy number counts at 1.2 and 3 mm and with a backward evolution model to place constraints on the evolution of the IR luminosity function and dust-obscured star formation in the past 13 billion years. Our results suggest a steep redshift evolution on the space density of DSFGs and confirm the flattening of the IR luminosity function at faint luminosities, with a slope of ${\alpha }_{\mathrm{LF}}=-{0.42}_{-0.04}^{+0.02}$ &lt;!-- --&gt; . We conclude that the dust-obscured component, which peaks at z ≈ 2-2.5, has dominated the cosmic history of star formation for the past ∼12 billion years, back to z ∼ 4. At z = 5, the dust-obscured star formation is estimated to be ∼35% of the total star formation rate density and decreases to 25%-20% at z = 6-7, implying a minor contribution of dust-enshrouded star formation in the first billion years of the universe. With the dust-obscured star formation history constrained up to the end of the epoch of reionization, our results provide a benchmark to test galaxy formation models, to study the galaxy mass assembly history, and to understand the dust and metal enrichment of the universe at early times.

Keywords: Luminosity function, Millimeter astronomy, Surveys, Dust continuum emission, Galaxy evolution, Star formation, Galaxy counts, Submillimeter astronomy, High-redshift galaxies, Galaxies
Sunspot Observations at the Eimmart Observatory and in Its Neighborhood during the Late Maunder Minimum (1681-1718). The Maunder Minimum (1645-1715; hereafter MM) is generally considered as the only grand minimum in the chronological coverage of telescopic sunspot observations. Characterized by scarce sunspot occurrences and their asymmetric concentrations in the southern solar hemisphere, the MM has frequently been associated with a special state of solar dynamo activity. As such, it is important to analyze contemporary observational records and improve our understanding of this peculiar interval, whereas the original records are frequently preserved in historical archives and can be difficult to access. In this study, we consult historical archives in the National Library of Russia, St. Petersburg, and analyze a series of sunspot observations conducted at the Eimmart Observatory from 1681 to 1709, which is the second-richest sunspot data set produced during the MM, following La Hire's series, among existing data sets. We have further extended our analyses to neighboring observations to extend our investigations up to 1718. We first analyze source documents and descriptions of observational instruments. Our analyses have significantly revised the existing data set, removed contaminations, and updated and labeled them as Eimmart Observatory (78 days), Altdorf Observatory (4 days), Hoffmann (22 days), and Wideburg (25 days). The revisions have updated the temporal coverage of the contemporary sunspot observations from 73.4% to 66.9% from 1677 to 1709. We have also derived the positions of the observed sunspot groups in comparison with contemporary observations. Our results indicate hemispheric asymmetry in the MM and recovery of sunspot groups in both hemispheres after 1716, supporting the common paradigm of the MM.

Keywords: Sunspot groups, Sunspot number, Solar activity, Maunder minimum, Solar-terrestrial interactions, Sunspot cycle
Multiple Stellar Populations of Globular Clusters from Homogeneous Ca-CN-CH-NH Photometry. VI. M3 (NGC 5272) Is Not a Prototypical Normal Globular Cluster. We present Ca-CN-CH-NH photometry for the well-known globular cluster (GC) M3 (NGC 5272). We show new evidence for two M3 populations with distinctly different carbon and nitrogen abundances, seen in a sharp division between CN-weak and CN-strong red-giant branches (RGBs) in M3. The CN-strong population shows a C-N anticorrelation that is a natural consequence of the CN cycle, while the CN-weak population shows at most a very weak C-N anticorrelation. Additionally, the CN-weak population exhibits an elongated spatial distribution that is likely linked to its fast rotation. Our derived metallicities reveal bimodal distributions in both populations, with ⟨[Fe/H]⟩ ≈ -1.60 and -1.45, which appear to be responsible for the discrete double RGB bumps in the CN-weak population and the large ${W}_{{\rm{F}}275{\rm{W}}-{\rm{F}}814{\rm{W}}}^{1G}$ &lt;!-- --&gt; range. From this discovery, we propose that M3 consists of two GCs, namely C1 (23%, ⟨[Fe/H]⟩ ≈ -1.60) and C2 (77%, ⟨[Fe/H]⟩ ≈ -1.45), each of which has its own C-N anticorrelation and structural and kinematical properties, which are strong indications of independent systems in M3. The fractions of the CN-weak population for both C1 and C2 are high compared to Galactic GCs but they are in good agreement with GCs in the Magellanic Clouds. We suggest that M3 is a merger remnant of two GCs, most likely in a dwarf galaxy environment, and accreted to our Galaxy later in time. This is consistent with recent proposals of an ex situ origin for M3. * Based on observations made with the Kitt Peak National Observatory (KPNO) 0.9 m telescope, which is operated by WIYN Inc. on behalf of a consortium of partner universities and organizations. † This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.

Keywords: Globular star clusters, Hertzsprung Russell diagram, Stellar abundances, Stellar evolution
A Jet-bases Emission Model of the EHT2017 Image of M87*. We carry out general relativistic ray-tracing radiative-transfer calculations to study whether a localized emission from plasma rings created at the stagnation surface in the jet funnel, to which we refer as stagnation rings, can explain the ring image of M87* observed by the Event Horizon Telescope (EHT) 2017. The resultant images consist of the direct image of the stagnation rings and the ring images formed via the strong deflection by the black hole (BH) gravity, to which we refer as quasi photon-ring. For the model with the BH spin a* = 0.99, the direct image of the counter-jet and quasi photon-ring are almost coincident to the photon ring with diameter ∼ 40 μas, while the approaching jet shows the small ring image inside them. The synthetic observation image assumes that the EHT2017 array is consistent with that observed in M87*, because the array is a bit sparse to detect the inner ring image. This indicates that the ring image in M87* may contain the important feature of the jet bases in addition to the photon ring. We find that forthcoming EHT observations can resolve the stagnation ring image and may enable us to explore the plasma-injection mechanism in the jet funnel.

Keywords: Black hole physics, Relativistic jets, Photon sphere, Very long baseline interferometers, Rotating black holes, Radiative transfer, Event horizons, Radiative processes, Supernovae, Astrophysical black holes
Stellar Collapse Diversity and the Diffuse Supernova Neutrino Background. The diffuse cosmic supernova neutrino background (DSNB) is an observational target of the gadolinium-loaded Super-Kamiokande (SK) detector and the forthcoming JUNO and Hyper-Kamiokande detectors. Current predictions are hampered by our still incomplete understanding of the supernova (SN) explosion mechanism and of the neutron star (NS) equation of state and maximum mass. In our comprehensive study we revisit this problem on grounds of the landscapes of successful and failed SN explosions obtained by Sukhbold et al. and Ertl et al. with parameterized one-dimensional neutrino engines for large sets of single-star and helium-star progenitors, with the latter serving as a proxy for binary evolution effects. Besides considering engines of different strengths, leading to different fractions of failed SNe with black hole (BH) formation, we also vary the NS mass limit and the spectral shape of the neutrino emission and include contributions from poorly understood alternative NS formation channels, such as accretion-induced and merger-induced collapse events. Since the neutrino signals of our large model sets are approximate, we calibrate the associated degrees of freedom by using state-of-the-art simulations of proto-NS cooling. Our predictions are higher than other recent ones because of a large fraction of failed SNe with long delay to BH formation. Our best-guess model predicts a DSNB ${\bar{\nu }}_{{\rm{e}}}$ &lt;!-- --&gt; -flux of ${28.8}_{-10.9}^{+24.6}$ &lt;!-- --&gt; cm-2 s-1 with ${6.0}_{-2.1}^{+5.1}$ &lt;!-- --&gt; cm-2 s-1 in the favorable measurement interval of [10, 30] MeV and ${1.3}_{-0.4}^{+1.1}$ &lt;!-- --&gt; cm-2 s-1 with ${\bar{\nu }}_{{\rm{e}}}$ &lt;!-- --&gt; energies &gt; 17.3 MeV, which is roughly a factor of two below the current SK limit. The uncertainty range is dominated by the still insufficiently constrained cosmic rate of stellar core-collapse events.

Keywords: Supernova neutrinos, Black holes, Core-collapse supernovae, Asymptotic giant branch, Diffuse radiation, Massive stars