Sazuna/UAT_keywords huggingface dataset:
Spectral Implications of Atomic Uncertainties in Optically Thin Hot Plasmas. Two new high-resolution X-ray spectroscopy missions, XRISM and Athena, will observe deeper and with higher X-ray resolution than ever before possible. Interpreting these new X-ray spectra will require understanding the impact that uncertainties on fundamental atomic quantities such as collisional cross sections, transition rates, and wavelengths have on spectral models. As millions of values are required to generate even a simple model of an optically thin hot plasma, most such rates exist only as theoretical calculations. We have developed methods to estimate the uncertainty in the final spectral calculations based on published experimental data and plausible approximations to the uncertainties in the underlying atomic data. We present an extension to the pyatomdb code which implements these methods and investigate the sensitivity of selected strong diagnostic lines in the X-ray bandpass (0.3-12 keV).

Keywords: X-ray astronomy, Atomic spectroscopy, Atomic data benchmarking
Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies. While tidal disruption events (TDEs) have long been heralded as laboratories for the study of quiescent black holes, the small number of known TDEs and uncertainties in their emission mechanism have hindered progress toward this promise. Here we present 17 new TDEs that have been detected recently by the Zwicky Transient Facility along with Swift UV and X-ray follow-up observations. Our homogeneous analysis of the optical/UV light curves, including 22 previously known TDEs from the literature, reveals a clean separation of light-curve properties with spectroscopic class. The TDEs with Bowen fluorescence features in their optical spectra have smaller blackbody radii, lower optical luminosities, and higher disruption rates compared to the rest of the sample. The small subset of TDEs that show only helium emission lines in their spectra have the longest rise times, the highest luminosities, and the lowest rates. A high detection rate of Bowen lines in TDEs with small photometric radii could be explained by the high density that is required for this fluorescence mechanism. The stellar debris can provide a source for this dense material. Diffusion of photons through this debris may explain why the rise and fade timescale of the TDEs in our sample are not correlated. We also report, for the first time, the detection of soft X-ray flares from a TDE on ∼day timescales. Based on the fact that the X-ray flares peak at a luminosity similar to the optical/UV blackbody luminosity, we attribute them to brief glimpses through a reprocessing layer that otherwise obscures the inner accretion flow.

Keywords: Tidal disruption, Astrophysical black holes, Galaxy nuclei
On the Rigidity Spectrum of Cosmic-Ray Variations within Propagating Interplanetary Disturbances: Neutron Monitor and SOHO/EPHIN Observations at ∼1-10 GV. The rigidity dependence of all Forbush decreases (FDs) recorded from 1995 to 2015 has been determined using neutron monitor (NM) and Solar and Heliospheric Observatory (SOHO) (EPHIN) spacecraft data, covering the energy (rigidity) range from ∼433 MeV (1 GV) to 9.10 GeV (10 GV). We analyzed a total of 421 events and determined the spectrum in rigidity with an inverse power-law fit. As a result, the mean spectral index was identified to be ⟨γF⟩ = 0.46 ± 0.02. The majority (∼66%) of the FDs have γF within the range 0.3-0.7. The remaining one-third of the events (∼33%) have either (very) soft or hard FD spectra, with the latter being more common than the former. Significant variations of γF occur within almost every FD event. During the initial FD decay phase the spectrum becomes gradually harder, in contrast to the recovery phase, when it becomes softer. Additionally, low energies (rigidities) seem to be better suited for studying the fine structure of interplanetary disturbances (primarily interplanetary coronal mass ejections) that lead to FDs. In particular, FDs recorded by the EPHIN instrument on SOHO better capture a two-step structure than FDs observed by NMs. Finally, the ejecta of an ICME, especially when identified as a magnetic cloud, often leads to abrupt changes in the slope of γF.

Keywords: Forbush effect, Corotating streams, Solar coronal mass ejections
A Consistent Modeling of Neutrino-driven Wind with Accretion Flow onto a Protoneutron Star and Its Implications for <SUP>56</SUP>Ni Production. Details of the explosion mechanism of core-collapse supernovae (CCSNe) are not yet fully understood. There is now an increasing number of successful examples of reproducing explosions in the first-principles simulations, which have shown a slow increase of explosion energy. However, it was recently pointed out that the growth rates of the explosion energy of these simulations are insufficient to produce enough 56Ni mass to account for observations. We refer to this issue as the "nickel mass problem" (Ni problem, hereafter) in this paper. The neutrino-driven wind is suggested as one of the most promising candidates for the solution to the Ni problem in previous literature, but a multidimensional simulation for this is computationally too expensive to allow long-term investigations. In this paper, we first built a consistent model of the neutrino-driven wind with an accretion flow onto a protoneutron star, by connecting a steady-state solution of the neutrino-driven wind and a phenomenological mass accretion model. Comparing the results of our model with the results of first-principles simulations, we find that the total ejectable amount of the neutrino-driven wind is roughly determined within ∼1 s from the onset of the explosion and the supplementable amount at a late phase (te ≳ 1 s) remains Mej ≲ 0.01 M⊙ at most. Our conclusion is that it is difficult to solve the Ni problem by continuous injection of 56Ni by the neutrino-driven wind. We suggest that the total amount of synthesized 56Ni can be estimated robustly if simulations are followed up to ∼2 s.

Keywords: Neutron stars, Supernova neutrinos, Core-collapse supernovae, Supernovae, Supernova dynamics
WOCS 5379: Detailed Analysis of the Evolution of a Post-mass-transfer Blue Straggler. The blue straggler binary WOCS 5379 is a member of the old (6-7 Gyr) open cluster NGC 188. WOCS 5379 comprises a blue straggler star with a white dwarf companion in a 120 day eccentric orbit. Combined with the orbital period, this helium white dwarf is evidence of previous mass transfer by a red giant. Detailed models of the system evolution from a progenitor main-sequence binary, including mass transfer, are made using the Modules for Experiments in Stellar Astrophysics. Both of the progenitor stars are evolved in the simulation. WOCS 5379 is well reproduced with a primary star of initial mass 1.19 M⊙, whose core becomes the white dwarf. The secondary star initially is 1.01 M⊙. The secondary finished receiving mass from the donor 300 Myr ago, having moved beyond the NGC 188 turnoff as a 1.20 M⊙ blue straggler. The successful model has a mass-transfer efficiency of 22%. This nonconservative mass transfer is key to expanding the orbit fast enough to permit stable mass transfer. Even so, the mass transfer begins with a short unstable phase, during which half of the accreted mass is transferred. With increasing mass, the secondary evolves from a radiative core to a convective core. The final blue straggler interior is remarkably similar to a 2.1 Gyr old 1.21 M⊙ main-sequence star at the same location in the H-R diagram. The white dwarf effective temperature is also reproduced, but the modeled white dwarf mass of 0.33 M⊙ is smaller than the measured mass of 0.42 M⊙.

Keywords: Binary stars, Close binary stars, White dwarf stars, Open star clusters, Blue straggler stars, Stellar evolution
The TW Hya Rosetta Stone Project. III. Resolving the Gaseous Thermal Profile of the Disk. The thermal structure of protoplanetary disks is a fundamental characteristic of the system that has wide-reaching effects on disk evolution and planet formation. In this study, we constrain the 2D thermal structure of the protoplanetary disk TW Hya structure utilizing images of seven CO lines. This includes new ALMA observations of 12CO J = 2-1 and C18O J = 2-1 as well as archival ALMA observations of 12CO J = 3-2, 13CO J = 3-2 and 6-5, and C18O J = 3-2 and 6-5. Additionally, we reproduce a Herschel observation of the HD J = 1-0 line flux and the spectral energy distribution and utilize a recent quantification of CO radial depletion in TW Hya. These observations were modeled using the thermochemical code RAC2D, and our best-fit model reproduces all spatially resolved CO surface brightness profiles. The resulting thermal profile finds a disk mass of 0.025 M⊙ and a thin upper layer of gas depleted of small dust with a thickness of ∼1.2% of the corresponding radius. Using our final thermal structure, we find that CO alone is not a viable mass tracer, as its abundance is degenerate with the total H2 surface density. Different mass models can readily match the spatially resolved CO line profiles with disparate abundance assumptions. Mass determination requires additional knowledge, and, in this work, HD provides the additional constraint to derive the gas mass and support the inference of CO depletion in the TW Hya disk. Our final thermal structure confirms the use of HD as a powerful probe of protoplanetary disk mass. Additionally, the method laid out in this paper is an employable strategy for extraction of disk temperatures and masses in the future.

Keywords: Protoplanetary disks, Astrochemistry
A Backscattering-dominated Prompt Emission Model for the Prompt Phase of Gamma-Ray Bursts. As a gamma-ray burst (GRB) jet drills its way through the collapsing star, it traps a baryonic "cork" ahead of it. Here we explore a prompt emission model for GRBs in which the jet does not cross the cork, but rather photons that are emitted deep in the flow largely by pair annihilation are scattered inside the expanding cork and escape largely from the back end of it as they push it from behind. Due to the relativistic motion of the cork, these photons are easily seen by an observer close to the jet axis peaking at ϵpeak ∼ few ×100 keV. We show that this model naturally explains several key observational features: (1) a high-energy power-law index β1 - 2 to - 5 with an intermediate thermal spectral region; (2) decay of the prompt emission light curve as ∼ t-2; (3) delay of soft photons; (4) a peak energy-isotropic energy (the so-called "Amati") correlation, ${\varepsilon }_{\mathrm{peak}}\sim {\varepsilon }_{\mathrm{iso}}^{m}$ , with m ∼ 0.45, resulting from different viewing angles (at low luminosities, our model predicts an observable turnoff in the Amati relation); (4) an anticorrelation between the spectral FWHM and time as t-1; (6) temporal evolution ϵpeak ∼ t-1, accompanied by an increase of the high-energy spectral slope with time; and (7) distribution of peak energies ϵpeak in the observed GRB population. The model is applicable for single-pulse GRB light curves and their respective spectra. We discuss the consequences of our model in view of current and future prompt emission observations.

Keywords: Gamma-ray bursts, Theoretical models, High energy astrophysics, Relativistic jets, Radiative processes
Observations of Magnetic Fields Surrounding LkHα 101 Taken by the BISTRO Survey with JCMT-POL-2. We report the first high spatial resolution measurement of magnetic fields surrounding LkHα 101, part of the Auriga-California molecular cloud. The observations were taken with the POL-2 polarimeter on the James Clerk Maxwell Telescope within the framework of the B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization of thermal dust emission at 850 μm is found to be mostly associated with the redshifted gas component of the cloud. The magnetic field displays a relatively complex morphology. Two variants of the Davis-Chandrasekhar-Fermi method, unsharp masking and structure function, are used to calculate the strength of magnetic fields in the plane of the sky, yielding a similar result of BPOS ∼ 115 μG. The mass-to-magnetic-flux ratio in critical value units, λ ∼ 0.3, is the smallest among the values obtained for other regions surveyed by POL-2. This implies that the LkHα 101 region is subcritical, and the magnetic field is strong enough to prevent gravitational collapse. The inferred δB/B0 ∼ 0.3 implies that the large-scale component of the magnetic field dominates the turbulent one. The variation of the polarization fraction with total emission intensity can be fitted by a power law with an index of α = 0.82 ± 0.03, which lies in the range previously reported for molecular clouds. We find that the polarization fraction decreases rapidly with proximity to the only early B star (LkHα 101) in the region. Magnetic field tangling and the joint effect of grain alignment and rotational disruption by radiative torques can potentially explain such a decreasing trend.

Keywords: Interstellar magnetic fields, Star formation, Molecular clouds
The Horizon Run 5 Cosmological Hydrodynamical Simulation: Probing Galaxy Formation from Kilo- to Gigaparsec Scales. Horizon Run 5 (HR5) is a cosmological hydrodynamical simulation that captures the properties of the universe on a Gpc scale while achieving a resolution of 1 kpc. Inside the simulation box, we zoom in on a high-resolution cuboid region with a volume of 1049 × 119 × 127 cMpc3. The subgrid physics chosen to model galaxy formation includes radiative heating/cooling, UV background, star formation, supernova feedback, chemical evolution tracking the enrichment of oxygen and iron, the growth of supermassive black holes, and feedback from active galactic nuclei in the form of a dual jet-heating mode. For this simulation, we implemented a hybrid MPI-OpenMP version of RAMSES, specifically targeted for modern many-core many-thread parallel architectures. In addition to the traditional simulation snapshots, lightcone data were generated on the fly. For the post-processing, we extended the friends-of-friend algorithm and developed a new galaxy finder PGalF to analyze the outputs of HR5. The simulation successfully reproduces observations, such as the cosmic star formation history and connectivity of galaxy distribution, We identify cosmological structures at a wide range of scales, from filaments with a length of several cMpc, to voids with a radius of ∼ 100 cMpc. The simulation also indicates that hydrodynamical effects on small scales impact galaxy clustering up to very large scales near and beyond the baryonic acoustic oscillation scale. Hence, caution should be taken when using that scale as a cosmic standard ruler: one needs to carefully understand the corresponding biases. The simulation is expected to be an invaluable asset for the interpretation of upcoming deep surveys of the universe.

Keywords: Hydrodynamical simulations, Galaxy formation, Large-scale structure of the universe
Alignment and Rotational Disruption of Dust. We reveal a deep connection between alignment of dust grains by radiative torques (RATs) and mechanical torques (METs) and the rotational disruption of grains introduced by Hoang et al. The disruption of grains happens if they have attractor points corresponding to high angular momentum (high J). We introduce fast disruption for grains that are directly driven to the high-J attractor on a timescale of spin-up, and slow disruption for grains that are first moved to the low-J attractor and gradually transported to the high-J attractor by gas collisions. The enhancement of grain magnetic susceptibility by iron inclusions expands the parameter space for high-J attractors and increases the percentage of grains experiencing the disruption. The increase in the magnitude of RATs or METs can increase the efficiency of fast disruption but, counterintuitively, decreases the effect of slow disruption by forcing grains toward low-J attractors, whereas the increase in gas density accelerates disruption by transporting grains faster to the high-J attractor. We also show that the disruption induced by RATs and METs depends on the angle between the magnetic field and the anisotropic flow. We find that pinwheel torques can increase the efficiency of fast disruption but may decrease the efficiency of slow disruption by delaying the transport of grains from the low-J to high-J attractors via gas collisions. The selective nature of the rotational disruption opens a possibility of observational testing of grain composition and physical processes of grain alignment.

Keywords: Interstellar dust, Astrosphere interstellar medium interactions, Interstellar dust extinction, Astrochemistry, Starlight polarization, Interstellar medium, Interstellar dust processes
Baryonic Feedback Measurement From KV450 Cosmic Shear Analysis. While baryonic feedback is one of the most important astrophysical systematics that we need to address in order to achieve precision cosmology, few weak lensing studies have directly measured its impact on the matter power spectrum. We report measurement of the baryonic feedback parameter with the constraints on its lower and upper limits from cosmic shear. We use the public data from the Kilo-Degree Survey and the VISTA Kilo-Degree Infrared Galaxy Survey spanning 450 deg2. Estimating both cosmological and feedback parameters simultaneously, we obtain ${A}_{{\rm{b}}}={1.01}_{-0.85}^{+0.80}$ , which shows a consistency with the dark matter-only (DMO) case at the ∼1.2σ level and a tendency toward positive feedback; the Ab = 0 (0.81) value corresponds to the DMO (OWLS AGN) case. Despite this full constraint of the feedback parameter, our ${S}_{8}\,(\equiv {\sigma }_{8}\sqrt{{{\rm{\Omega }}}_{m}/0.3})$ measurement ( ${0.739}_{-0.035}^{+0.036}$ ) shifts by only ∼6% of the statistical error, compared to the previous measurement. When we assume the flat ΛCDM cosmology favored by the Nine-Year Wilkinson Microwave Anisotropy Probe (Planck) result, the feedback parameter is constrained to be ${A}_{{\rm{b}}}={1.21}_{-0.54}^{+0.61}$ ( ${1.60}_{-0.52}^{+0.53}$ ), which excludes the DMO case at the ∼2.2σ (∼3.1σ) level.

Keywords: Cosmology, Weak gravitational lensing, Large-scale structure of the universe, Observational cosmology, Cosmological parameters from large-scale structure, Astrophysical processes, Gravitational lensing shear
Origin of Galactic Spurs: New Insight from Radio/X-Ray All-sky Maps. In this study, we analyze giant Galactic spurs seen in both radio and X-ray all-sky maps to reveal their origins. We discuss two types of giant spurs: one is the brightest diffuse emission near the map's center, which is likely to be related to Fermi bubbles (NPSs/SPSs, north/south polar spurs, respectively), and the other is weaker spurs that coincide positionally with local spiral arms in our Galaxy (LAS, Local Arm spur). Our analysis finds that the X-ray emissions, not only from the NPS but also from the SPS, are closer to the Galactic center by ∼5° compared with the corresponding radio emission. Furthermore, larger offsets of 10°-20° are observed in the LASs; however, they are attributed to different physical origins. Moreover, the temperature of the X-ray emission is kT ≃ 0.2 keV for the LAS, which is systematically lower than those of the NPS and SPS (kT ≃ 0.3 keV) but consistent with the typical temperature of Galactic halo gas. We argue that the radio/X-ray offset and the slightly higher temperature of the NPS/SPS X-ray gas are due to the shock compression/heating of halo gas during a significant Galactic explosion in the past, whereas the enhanced X-ray emission from the LAS may be due to the weak condensation of halo gas in the arm potential or star formation activity without shock heating.

Keywords: X-ray astronomy, Spiral arms, Interstellar medium, Radio astronomy, Superbubbles
Dust, Gas, and Metal Content in Star-forming Galaxies at z ∼ 3.3 Revealed with ALMA and Near-IR Spectroscopy. We conducted submillimeter observations with the Atacama Large Millimeter/submillimeter Array (ALMA) of star-forming galaxies at z ∼ 3.3, whose gas-phase metallicities have been measured previously. We investigated the dust and gas contents of the galaxies at z ∼ 3.3 and studied the interaction of galaxies with their circumgalactic or intergalactic medium at this epoch by probing their gas mass fractions and gas-phase metallicities. Single-band dust continuum emission tracing dust mass and the relation between the gas-phase metallicity and gas-to-dust mass ratio were used to estimate the gas masses. The estimated gas mass fractions and depletion timescales are fgas= 0.20-0.75 and tdep= 0.09-1.55 Gyr. Although the galaxies appear to be tightly distributed around the star-forming main sequence at z ∼ 3.3, both quantities show a wider spread at a fixed stellar mass than expected from the scaling relation, suggesting a large diversity of fundamental gas properties in star-forming galaxies that apparently lie on the main sequence. When we compared gas mass fraction and gas-phase metallicity in star-forming galaxies at z ∼ 3.3 and at lower redshifts, star-forming galaxies at z ∼ 3.3 appear to be more metal poor than local galaxies with similar gas mass fractions. Using the gas regulator model to interpret this offset, we find that this can be explained by a higher mass-loading factor, suggesting that the mass-loading factor in outflows increases at earlier cosmic times.

Keywords: Galaxy formation, High-redshift galaxies, Galaxy evolution, Interstellar medium
Synthetic Light Curves of Accretion Variability in T Tauri Stars. Photometric observations of accreting, low-mass, pre-main-sequence stars (i.e., Classical T Tauri stars; CTTS) have revealed different categories of variability. Several of these classifications have been linked to changes in $\dot{M}$ . To test how accretion variability conditions lead to different light-curve morphologies, we used 1D hydrodynamic simulations of accretion along a magnetic field line coupled with radiative transfer models and a simple treatment of rotation to generate synthetic light curves. We adopted previously developed metrics in order to classify observations to facilitate comparisons between observations and our models. We found that stellar mass, magnetic field geometry, corotation radius, inclination, and turbulence all play roles in producing the observed light curves and that no single parameter is entirely dominant in controlling the observed variability. While the periodic behavior of the light curve is most strongly affected by the inclination, it is also a function of the magnetic field geometry and inner disk turbulence. Objects with either pure dipole fields, strong aligned octupole components, or high turbulence in the inner disk all tend to display accretion bursts. Objects with anti-aligned octupole components or aligned, weaker octupole components tend to show light curves with slightly fewer bursts. We did not find clear monotonic trends between the stellar mass and empirical classification. This work establishes the groundwork for more detailed characterization of well-studied targets as more light curves of CTTS become available through missions such as the Transiting Exoplanet Survey Satellite (TESS).

Keywords: Hydrodynamical simulations, Light curve classification , Stellar accretion, Classical T Tauri stars