Sazuna/UAT_keywords huggingface dataset:
Exploring the Fate of Stellar Core Collapse with Supernova Relic Neutrinos. Core collapse of massive stars leads to different fates for various physical factors, which gives different spectra of the emitted neutrinos. We focus on the supernova relic neutrinos (SRNs) as a probe to investigate the stellar collapse fate. We present the SRN fluxes and event rate spectra at a detector for three resultant states after stellar core collapse, the typical mass neutron star, the higher mass neutron star, or the failed supernova forming a black hole, based on different nuclear equations of state. Then possible SRN fluxes are formed as mixtures of the three components. We also show the expected sensitivities at the next-generation water-based Cherenkov detectors, SK-Gd and Hyper-Kamiokande, as constraining the mixture fractions. This study provides a practical example of extracting astrophysical constraints through SRN measurement.

Keywords: Neutron stars, Supernova neutrinos, Black holes, Core-collapse supernovae, Massive stars, Neutrino astronomy
The Origin of the Vanishing Soft X-Ray Excess in the Changing-look Active Galactic Nucleus Mrk 590. We have studied the nature and origin of the soft X-ray excess detected in the interesting changing-look active galactic nucleus (CLAGN) Mrk 590 using two decades of multiwavelength observations from XMM-Newton, Suzaku, Swift, and NuSTAR. In light of vanishing soft excess in this CLAGN, we test two models, "the warm Comptonization" and "the ionized disk reflection," using extensive UV/X-ray spectral analysis. Our main findings are as follows: (1) the soft X-ray excess emission, last observed in 2004, vanished in 2011 and never reappeared in any of the later observations; (2) we detected a significant variability (~300%) in the observed optical-UV and power-law flux between observations with the lowest state (L bol = 4.4 × 1043 erg s-1, in 2016) and those with the highest state (L bol = 1.2 × 1044 erg s-1, in 2018); (3) the UV and power-law fluxes follow the same temporal pattern; (4) the photon index showed a significant variation ( ${\rm{\Gamma }}={1.88}_{-0.08}^{+0.02}$ and ${\rm{\Gamma }}={1.58}_{-0.03}^{+0.02}$ in 2002 and 2021, respectively) between observations; (5) no Compton hump was detected in the source spectra, but a narrow Fe Kα line is present in all observations; (6) we detected a high-energy cutoff in power-law continuum ( ${92}_{-25}^{+55}\,\mathrm{keV}$ and ${60}_{-08}^{+10}\,\mathrm{keV}$ ) with the latest NuSTAR observations; (7) the warm Comptonization model needs an additional diskbb component to describe the source UV bump; and (8) there is no correlation between the Eddington rate and the soft excess as found in other CLAGNs. We conclude that, given the spectral variability in UV/X-rays, the ionized disk reflection or the warm Comptonization models may not be adequate to describe the vanishing soft excess feature observed in Mrk 590.

Keywords: Seyfert galaxies, X-ray active galactic nuclei, Active galactic nuclei
The Quasar Luminosity Function at z   5 via Deep Learning and Bayesian Information Criterion. Understanding the faint end of quasar luminosity function (LF) at a high redshift is important since the number density of faint quasars is a critical element in constraining ultraviolet (UV) photon budgets for ionizing the intergalactic medium (IGM) in the early universe. Here, we present quasar LF reaching M 1450 ~ -22.0 AB mag at z ~ 5, about 1 mag deeper than previous UV LFs. We select quasars at z ~ 5 with a deep learning technique from deep data taken by the Hyper Suprime-Cam Subaru Strategic Program, covering a 15.5 deg2 area. Beyond the traditional color selection method, we improved the quasar selection by training an artificial neural network to distinguish z ~ 5 quasars from nonquasar sources based on their colors and adopting the Bayesian information criterion that can further remove high-redshift galaxies from the quasar sample. When applied to a small sample of spectroscopically identified quasars and galaxies, our method is successful in selecting quasars at ~83% efficiency (5/6) while minimizing the contamination rate of high-redshift galaxies (1/8) by up to three times compared to the selection using color selection alone (3/8). The number of our final quasar candidates with M 1450 &lt; -22.0 mag is 35. Our quasar UV LF down to M 1450 = -22 mag or even fainter (M 1450 = -21 mag) suggests a rather low number density of faint quasars and the faint-end slope of $-{1.6}_{-0.19}^{+0.21}$ , favoring a scenario where quasars play a minor role in ionizing the IGM at high redshift.

Keywords: Luminosity function, Neural networks, Quasars, Surveys, Astrostatistics, Bayesian information criterion, Reionization
An Insight-HXMT View of the mHz Quasi-regular Modulation Phenomenon in the Black Hole X-Ray Binary 4U 1630-47. Here we report the spectral-timing results of the black hole X-ray binary 4U 1630-47 during its 2021 outburst using observations from the Hard X-ray Modulation Telescope (Insight-HXMT). Type C quasi-periodic oscillations (QPOs) in ~1.6-4.2 Hz and quasi-regular modulation (QRM) near 60 mHz are detected during the outburst. The mHz QRM has a fractional rms of ~10%-16% in the 8-35 keV energy band with a Q factor (frequency/width) of ~2-4. Benefiting from the broad energy band of Insight-HXMT, we study the energy dependence of the ~60 mHz QRM in 1-100 keV for the first time. We find that the fractional rms of the mHz QRM increases with photon energy, while the time lags of the mHz QRM are soft and decrease with photon energy. Fast recurrence of the mHz QRM, in a timescale of less than 1 hr, has been observed during the outburst. During this period, the corresponding energy spectra moderately change when the source transitions from the QRM state to the non-QRM state. The QRM phenomenon also shows a dependence with the accretion rate. We suggest that the QRM could be caused by an unknown accretion instability aroused from the corona.

Keywords: Accretion, Low-mass x-ray binary stars, Stellar mass black holes, Astrophysical black holes
The Longest Delay: A 14.5 yr Campaign to Determine the Third Time Delay in the Lensing Cluster SDSS J1004+4112. We present new light curves for the four bright images of the five image cluster-lensed quasar gravitational lens system SDSS J1004+4112. The light curves span 14.5 yr and allow the measurement of the time delay between the trailing bright quasar image D and the leading image C. When we fit all four light curves simultaneously and combine the models using the Bayesian information criterion, we find a time delay of Δt DC = 2458.47 ± 1.02 days (6.73 yr), the longest ever measured for a gravitational lens. For the other two independent time delays we obtain Δt BC = 782.20 ± 0.43 days (2.14 yr) and Δt AC = 825.23 ± 0.46 days (2.26 yr), in agreement with previous results. The information criterion is needed to weight the results for light curve models with different polynomial orders for the intrinsic variability and the effects of differential microlensing. The results using the Akaike information criterion are slightly different, but, in practice, the absolute delay errors are all dominated by the ~4% cosmic variance in the delays rather than the statistical or systematic measurement uncertainties. Despite the lens being a cluster, the quasar images show slow differential variability due to microlensing at the level of a few tenths of a magnitude.

Keywords: Galaxy clusters, Quasars, Strong gravitational lensing, Light curves, Gravitational lensing, Photometry
A Mass Model for the Lensing Cluster SDSS J1004+4112: Constraints from the Third Time Delay. We have built a new model for the lens system SDSS J1004+4112 including the recently measured time delay of the fourth quasar image. This time delay has a strong influence on the inner mass distribution of the lensing cluster (ρ ∝ r -α ) allowing us to determine $\alpha ={1.18}_{-0.03(-0.18)}^{+0.02(+0.11)}$ at the 68% (95%) confidence level in agreement with hydrodynamical simulations of massive galaxy clusters. We find an offset between the brightest cluster galaxy and the dark matter halo of ${3.8}_{-0.7(-1.3)}^{+0.6(+1.4)}$ kpc at 68% (95%) confidence which is compatible with other galaxy cluster measurements. As an observational challenge, the estimated time delay between the leading image C and the faint (I = 24.7) fifth image E is roughly 8 yr.

Keywords: Galaxy clusters, Dark matter distribution, Quasars, Strong gravitational lensing, Gravitational lensing
Chemical Diversity in Protoplanetary Disks and Its Impact on the Formation History of Giant Planets. Giant planets can interact with multiple and chemically diverse environments in protoplanetary disks while they form and migrate to their final orbits. The way this interaction affects the accretion of gas and solids shapes the chemical composition of the planets and of their atmospheres. Here we investigate the effects of different chemical structures of the host protoplanetary disk on the planetary composition. We consider both scenarios of molecular (inheritance from the prestellar cloud) and atomic (complete chemical reset) initial abundances in the disk. We focus on four elemental tracers of different volatility: C, O, N, and S. We explore the entire extension of possible formation regions suggested by observations by coupling the disk chemical scenarios with N-body simulations of forming and migrating giant planets. The planet formation process produces giant planets with chemical compositions significantly deviating from that of the host disk. We find that the C/N, N/O, and S/N ratios follow monotonic trends with the extent of migration. The C/O ratio shows a more complex behavior, dependent on the planet accretion history and on the chemical structure of the formation environment. The comparison between S/N* and C/N* (where * indicates normalization to the stellar value), constrains the relative contribution of gas and solids to the total metallicity. Giant planets whose metallicity is dominated by the contribution of the gas are characterized by N/O* &gt; C/O* &gt; C/N* and allow to constrain the disk chemical scenario. When the planetary metallicity is instead dominated by the contribution of the solids we find that C/N* &gt; C/O* &gt; N/O*.

Keywords: Exoplanet atmospheric composition , Abundance ratios, Planetary atmospheres, Chemical abundances, Astrochemistry, Protoplanetary disks, Metallicity, Extrasolar gaseous giant planets, Planet formation
Tidal Wave Breaking in the Eccentric Lead-in to Mass Transfer and Common Envelope Phases. The evolution of many close binary and multiple star systems is defined by phases of mass exchange and interaction. As these systems evolve into contact, tidal dissipation is not always sufficient to bring them into circular, synchronous orbits. In these cases, encounters of increasing strength occur while the orbit remains eccentric. This paper focuses on the outcomes of close tidal passages in eccentric orbits. Close eccentric passages excite dynamical oscillations about the stars' equilibrium configurations. These tidal oscillations arise from the transfer of orbital energy into oscillation mode energy. When these oscillations reach sufficient amplitude, they break near the stellar surface. The surface wave-breaking layer forms a shock-heated atmosphere that surrounds the object. The continuing oscillations in the star's interior launch shocks that dissipate into the atmosphere, damping the tidal oscillations. We show that the rapid, nonlinear dissipation associated with the wave breaking of fundamental oscillation modes therefore comes with coupled mass loss to the wave-breaking atmosphere. The mass ratio is an important characteristic that defines the relative importance of mass loss and energy dissipation and therefore determines the fate of systems evolving under the influence of nonlinear dissipation. The outcome can be rapid tidal circularization (q ≪ 1) or runaway mass exchange (q ≫ 1).

Keywords: Close binary stars, Hydrodynamical simulations, Tidal interaction, Common envelope evolution
Reorientation Rates of Structural and Kinematic Axes in Simulated Massive Galaxies and the Origins of Prolate Rotation. In this work, we analyze a sample of ~4000 massive (M * ≥ 1011 M ⊙ at z = 0) galaxies in TNG300, the (300Mpc)3 box of the IllustrisTNG simulation suite. We characterize the shape and kinematics of these galaxies with a focus on the kinematic misalignment (Ψint) between the angular momentum (AM) and morphological major axis. We find that the traditional purely shape- or kinematics-based classifications are insufficient to characterize the diversity of our sample and define a new set of classes based on the rates of change of the galaxies' morphological and kinematic axes. We show that these classes are mostly stable over time and correspond to six distinct populations of galaxies: the rapid AM reorienters (58% of our sample), unsettled galaxies (10%), spinning disks (10%), twirling cigars (16%), misaligned slow reorienters (3%), and regular prolate rotators (galaxies that display major axis rotation; 2%). We demonstrate that the most-recent significant (mass-ratio μ &gt; 1/10) mergers of these galaxies are the primary cause for their present-day properties and find that these mergers are best characterized at the point of the satellite's final infall-that is, much closer to the final coalescence than has been previously thought. We show that regular prolate rotators evolve from spinning disk progenitors that experience a radial merger along their internal AM direction. Finally, we argue that these regular prolate rotators are distinct from the similarly sized population of rapid AM reorienters with large Ψint, implying that a large Ψint is not a sufficient condition for major axis rotation.

Keywords: Galaxy mergers, Galaxy structure, Galaxy kinematics, Galaxy evolution
Signatures of Impact-driven Atmospheric Loss in Large Ensembles of Exoplanets. The results of large-scale exoplanet transit surveys indicate that the distribution of small planet radii is likely sculpted by atmospheric loss. Several possible physical mechanisms exist for this loss of primordial atmospheres, each of which produces a different set of observational signatures. In this study, we investigate the impact-driven mode of atmosphere loss via N-body simulations. We compare the results from giant impacts, at a demographic level, to results from another commonly invoked method of atmosphere loss, photoevaporation. Applying two different loss prescriptions to the same sets of planets, we then examine the resulting distributions of planets with retained primordial atmospheres. As a result of this comparison, we identify two new pathways toward discerning the dominant atmospheric-loss mechanism at work. Both of these pathways involve using transit multiplicity as a diagnostic, in examining the results of follow-up atmospheric and radial velocity surveys.

Keywords: Exoplanet evolution, Exoplanet atmospheres, Exoplanets
Ultraviolet Spectroscopy and TARDIS Models of the Broad-lined Type Ic Supernova 2014ad. Few published ultraviolet (UV) spectra exist for stripped-envelope supernovae and none to date for broad-lined Type Ic supernovae (SNe Ic-bl). These objects have extremely high ejecta velocities and are the only supernova type directly linked to gamma-ray bursts (GRBs). Here we present two epochs of HST/STIS spectra of the SN Ic-bl 2014ad, the first UV spectra for this class. We supplement this with 26 new epochs of ground-based optical spectra, augmenting a rich spectral time series. The UV spectra do not show strong features and are consistent with broadened versions of other SN Ic spectra observed in the UV. We measure Fe II 5169 Å velocities and show that SN 2014ad has even higher ejecta velocities than most SNe Ic both with and without observed GRBs. We construct models of the SN 2014ad UV+optical spectra using TARDIS, a 1D Monte Carlo radiative-transfer spectral synthesis code. The models fit the data well at multiple epochs in the optical but underestimate the flux in the UV, likely due to simplifying assumptions. We find that high densities at high velocities are needed to reproduce the spectra, with ~3 M ☉ of material at v &gt; 22,000 km s-1, assuming spherical symmetry. Our nebular line fits suggest a steep density profile at low velocities. Together, these results imply a higher total ejecta mass than estimated from previous light-curve analysis and expected from theory. This may be reconciled by a flattening of the density profile at low velocity and extra emission near the center of the ejecta.

Keywords: Type Ic supernovae, Supernovae
Spatial Scales and Time Variation of Solar Subsurface Convection. Spectral analysis of the spatial structure of solar subphotospheric convection is carried out for subsurface flow maps constructed using the time-distance helioseismological technique. The source data are obtained from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory from 2010 May to 2020 September. A spherical harmonic transform is applied to the horizontal velocity divergence field at depths from 0 to 19 Mm. The range of flow scales is fairly broad in the shallow layers and narrows as the depth increases. The horizontal flow scales increase rapidly with depth, from supergranulation to giant-cell values, and indicate the existence of large-scale convective motions in the near-surface shear layer. The results can naturally be interpreted in terms of a superposition of differently scaled flows localized at different depth intervals. There is some tendency toward the emergence of meridionally elongated (banana-shaped) convection structures in the deep layers. The total power of the convective flows is anticorrelated with the sunspot number variation over the solar activity cycle in shallow subsurface layers, and positively correlated at larger depths, which is suggestive of the depth redistribution of the convective flow energy due to the action of magnetic fields.

Keywords: Helioseismology, Solar granulation, Solar activity
The Roles of Flux Tube Entropy and Effective Gravity in the Inward Plasma Transport at Saturn. The inward plasma transport at the Saturnian magnetosphere is examined using the flux tube interchange stability formalism developed by Southwood &amp; Kivelson. Seven events are selected. Three cases are considered: (1) the injected flux tube and ambient plasmas are nonisotropic, (2) the injected flux tube and ambient plasmas are isotropic, and (3) the injected flux tube plasma is isotropic, but the ambient plasma is nonisotropic. Case 1 may be relevant for fresh injections, while case 3 may be relevant for old injections. For cases 1 and 2, all but one event have negative stability conditions, suggesting that the flux tube should be moving inward. For case 3, the injections located at L &gt; 11 have negative stability conditions, while four out of five of the injections at L &lt; 9 have positive stability conditions. The positive stability condition for small L suggests that the injection may be near its equilibrium position and possibly oscillating thereabouts-hence the outward transport if the flux tube overshot the equilibrium position. The flux tube entropy plays an important role in braking the plasma inward transport. When the stability condition is positive, it is because the entropy term, which is positive, counters and dominates the effective gravity term, which is negative for all the events. The ambient plasma and drift-out from adjacent injections can affect the stability and the inward motion of the injected flux tube. The results have implications for inward plasma transport in the Jovian magnetosphere, as well as other fast-rotating planetary magnetospheres.

Keywords: Planetary magnetospheres, Saturn, Space plasmas
Relationship between Successive Flares in the Same Active Region and SHARP Parameters. A solar active region (AR) may produce multiple notable flares during its passage across the solar disk. We investigate successive flares from flare-eruptive ARs, and explore their relationship with solar magnetic parameters. We examine six ARs in this study, each with at least one major flare above X1.0. The Space-weather HMI Active Region Patch (SHARP) is employed in this study to parameterize the ARs. We aim to identify the most flare-related SHARP parameters and lay foundation for future practical flare forecasts. We first evaluate the correlation coefficients between the SHARP parameters and the successive flare production. Then we adopt a Natural Gradient Boost (NGBoost) method to analyze the relationship between the SHARP parameters and the successive flare bursts. Based on the correlation analysis and the importance distribution returned from NGBoost, we select the eight most flare-related SHARP parameters. Finally, we discuss the physical meanings of the eight selected parameters and their relationship with flare production.

Keywords: Solar active regions, Solar flares, Solar magnetic fields
Multispacecraft Remote Sensing and In Situ Observations of the 2020 November 29 Coronal Mass Ejection and Associated Shock: From Solar Source to Heliospheric Impacts. We investigate the source eruption, propagation and expansion characteristics, and heliospheric impacts of the 2020 November 29 coronal mass ejection (CME) and associated shock, using remote sensing and in situ observations from multiple spacecraft. A potential-field source-surface model is employed to examine the coronal magnetic fields surrounding the source region. The CME and associated shock are tracked from the early stage to the outer corona using extreme ultraviolet and white light observations. Forward models are applied to determine the structures and kinematics of the CME and the shock near the Sun. The shock shows an ellipsoidal structure, expands in all directions, and encloses the whole Sun as viewed from both SOHO and STEREO A, which results from the large expansion of the CME flux rope and its fast acceleration. The structure and potential impacts of the shock are mainly determined by its radial and lateral expansions. The CME and shock arrive at Parker Solar Probe and STEREO A. Only based on the remote sensing observations, it is difficult to predict whether and when the CME/shock would arrive at the Earth. Combining Wind in situ measurements and Wang-Sheeley-Arge-ENLIL simulation results, we confirm that the far flank of the CME (or the CME leg) arrives at the Earth with no shock signature. These results highlight the importance of multipoint remote sensing and in situ observations for determining the heliospheric impacts of CMEs.

Keywords: Solar wind, Interplanetary shocks, Solar coronal mass ejections