Sazuna/UAT_keywords huggingface dataset:
Exploring Contact Binaries: Observational Analysis of Four W Uma Binaries Using Photometry and Spectroscopy. We present the multiband photometric and low-resolution spectroscopic analysis of four W Ursae Majoris eclipsing binaries (EWs)—J080510.1+141528 (hereinafter as J0805a), J080516.3+143138 (hereinafter as J0805b), J143358.7+053953 (hereinafter as J1433), and J143458.4+054143 (hereinafter as J1434). The multiband ground based photometric data are collected using the 1.3 m Devasthal Fast Optical Telescope, while we also make use of Transiting Exoplanet Survey Satellite (TESS) photometric observations. The spectroscopic analysis is based on the low-resolution observations by the 4 m Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). The ephemerides of these systems are updated using the photometric data from TESS and other photometric surveys. The system J0805b shows a secular change in the orbital period with a period change rate of 4.2 (±0.1) × 10‑7 days per year, while the orbital period change rate for J1433 is calculated as ‑1.1 (±0.1) × 10‑6 days per year. The mass-transfer rate for J0805b is found to be dM1/dt = ‑1.56(±0.07) × 10‑6 M⊙ yr‑1 and dM1/dt = ‑7.95(±0.87) × 10‑7 M⊙ yr‑1 for J1433. All the systems have inclination &gt; 79∘except J1433, which has an inclination of 72 .° 8. The mass ratios (less massive to more massive component) for these targets are &lt;0.5. All the systems except J0805b are A-subtype contact binaries. The absolute parameters of the systems are determined using Gaia DR3 parallax and reddening information. The LAMOST spectra are analyzed using the spectral subtraction technique. A small excess emission is detected for J1433 in Hα and Hβ region. The systems are plotted on a Hertzsprung–Russell diagram and compared with previously studied systems. The mass ratio versus radius ratio relation is also investigated for these systems.

Keywords: Observational astronomy, Multi-color photometry, Fundamental parameters of stars, Spectroscopy, Eclipsing binary stars, Contact binary stars
Multipoint Observations and Modeling of the 2021 November 4 Forbush Decrease Using Solar Orbiter, CSES-01, and Ground-based Neutron Monitor Data. During their propagation in the heliosphere, interplanetary coronal mass ejections (ICMEs) interact with galactic cosmic ray (GCR) particles, modifying their spectrum and driving anisotropies. We analyze the first large Forbush decrease (FD) of Solar Cycle 25 on 2021 November 3–5 by using multipoint in situ observations and neutron monitors to study the association between FD characteristics and ICME. We use the Grad–Shafranov reconstruction to infer the magnetic field configuration of the ICME. We model the neutron monitor response through primary spectrum and anisotropy. The primary spectrum is parameterized with the force-field approximation and the anisotropy is modeled through a spherical harmonic expansion. We optimize the model parameters during the FD by using ground-based observations provided by the worldwide neutron-monitor network. The model's results are compared with space-based measurements of the differential proton flux measured by the HEPD-01 detector on board the CSES-01 satellite and of the integral counts of both the High-Energy Particle Detector (HEPD-01) and the High Energy Telescope on board the Solar Orbiter. Anisotropy develops during the ICME passage, within the magnetic flux rope (MFR) and is found to be bidirectional. The force-field parameterization of the primary GCR fluxes based on ground-based measurements is found to be in very good agreement with spacecraft observations in the sub-GeV range. The GCR anisotropy obtained by fitting the model to ground-based observations is consistent with interplanetary magnetic field observations. The results suggest that the local magnetic field has a substantial axial component that is aligned to the MFR axis, and determines the GCR anisotropy at the typical neutron monitor energies.

Keywords: Galactic cosmic rays, Forbush effect, Solar coronal mass ejections
Spatially Resolved Star Formation Rate and Dust Attenuation of Nearby Galaxies from CALIFA, GALEX, and WISE Data. We study star formation rate (SFR) indicators and dust attenuation of 74 nearby star-forming galaxies on kiloparsec scales, based on GALEX far-ultraviolet (FUV) and WISE mid-infrared (MIR) images with CALIFA optical integral field spectroscopic data. We obtain hybrid SFR indicators by combining the observed FUV and MIR luminosities and calibrate them using the dust-corrected Hα luminosity as a reference SFR. The simple linear combination appears to follow well the reference SFR, but the calibration residual shows a significant dependence on the specific SFR (sSFR), which can be removed by employing the combination coefficient or conversion offset that varies with the sSFR. In the plane of gas versus stellar attenuation, the median trend line's slope (≈stellar-to-gas attenuation ratio) changes from 0.44 to 1.0 with increasing attenuation. The differential attenuation, defined as the deviation of stellar attenuation from the median trend line, is strongly correlated with the SFR surface density and sSFR, compatible with the two-component dust model. The differential attenuation seems to be affected by both local and global factors.

Keywords: Interstellar line emission, Stellar gas distribution, Interstellar dust extinction, Dust continuum emission, Star formation
Asteroseismology of Metal-poor Red Giants Observed by TESS. Galactic archeology has long been limited by a lack of precise masses and ages for metal-poor stars in the Milky Way's thick disk. However, with TESS providing a growing number of photometric observations, it is possible to calculate masses and ages for more solar-like oscillators than ever using asteroseismology. We have used the pySYD pipeline to determine global asteroseismic parameters, and calculated the masses and ages of 506 metal-poor ([M/H] &lt; ‑0.5) red giants observed by TESS. Our findings appear to show metallicity-dependent mass loss on the upper red giant branch and identify a set of "young" high-α stars that have been detected in other studies. We also find that 32.6% of the metal-poor stars appear to be binary interaction products, and four stars with stellar ages that could be from the Gaia-Enceladus/Sausage system. In combination with existing ages from Kepler/K2, these data can be compared to galactic evolution models to better determine the formation history of the Galaxy.

Keywords: Stellar populations, Galactic archaeology, Stellar astronomy, Stellar oscillations, Asteroseismology
DIISC-V: Variations in Hα-to-FUV Star Formation Rate Ratios Across Star-forming Regions in Nearby Galaxies. We present the variations in far-ultraviolet (FUV) and Hα star formation rates (SFR), SFRUV and SFRHα, respectively, at subkiloparsec scales in 11 galaxies as part of the Deciphering the Interplay between the Interstellar Medium, Stars, and the Circumgalactic medium survey. Using archival GALEX FUV imagery and Hα+[N II] narrowband images obtained with the Vatican Advanced Technology Telescope, we detect a total of 1335 (FUV-selected) and 1474 (Hα-selected) regions of recent high-mass star formation, respectively. We find the Hα-to-FUV SFR ratios tend to be lower primarily for FUV-selected regions, where SFRHα generally underestimates the SFR by an average factor of 2─3, for SFR &lt; 10−4 M⊙ yr−1. In contrast, the SFRs are generally observed to be consistent for Hα-selected regions. This discrepancy arises from morphological differences between the two indicators. Extended FUV morphologies and larger areas covered by FUV-only regions, along with decreasing overlap between FUV clumps and compact H II regions with R/R25 suggest that stochastic sampling of the initial mass function may be more pronounced in the outer regions of galaxies. Our observed Hα-to-FUV SFR ratios are also consistent with stochastic star formation model predictions. However, using larger apertures that include diffuse FUV emission results in an offset of 1 dex between SFRHα and SFRUV, suggesting that the observed low Hα-to-FUV SFR ratios in galaxies are likely caused by diffuse FUV emission, which can contribute ∼60%─90% to the total FUV flux.

Keywords: Spiral galaxies, Star forming regions, H alpha photometry, Star formation, Ultraviolet photometry, H II regions, Stellar associations
Size–Frequency Distribution of Terrestrial Leftover Planetesimals and S-complex Implanted Asteroids. The isotopic composition of meteorites linked to S-complex asteroids has been used to suggest that these asteroids originated in the terrestrial planet's region, i.e., within 1.5 au, and later got implanted into the main asteroid belt (MAB). Dynamical models of planet formation support this view. Yet it remains to be demonstrated whether the currently observed size–frequency distribution (SFD) of S-complex bodies in the MAB can be reproduced via this implantation process. Here we studied the evolution of the SFD of planetesimals during the accretion of terrestrial planets with the code LIPAD self-consistently accounting for growth and fragmentation of planetesimals. In our simulations we vary the initial surface density of planetesimals, the gaseous disk lifetime, and the power slope of the initial planetesimals' SFD. We compared the final SFDs of leftover planetesimals in the terrestrial planet region with the SFD of observed S-complex MAB objects (D &gt; 100 km). We found that the SFDs of our planetesimal populations and that of S-complex MAB objects show very similar cumulative power index (i.e., q ≈ 3.15 in N(&gt;D) ∝ D‑q) for slopes in the diameter range 100 km &lt; D &lt; 400 km by the end of our simulations. Our results support the hypothesis of S-complex MAB implantation from the terrestrial planet forming region, assuming implantation is size independent, and imply that implantation efficiency is smaller than  O (10–2–10–4) to avoid overimplantation of (4) Vesta-sized objects or larger.

Keywords: Asteroid belt, Solar system formation, Solar system terrestrial planets, Asteroid dynamics
EDEN: Exploring Disks Embedded in N-body Simulations of Milky Way–mass Halos from Symphony. We investigate the impact of galactic disks on the tidal stripping of cold dark matter subhalos within Milky Way (MW)-mass halos (Mvir ∼ 1012M⊙) using a new simulation suite, EDEN. By re-simulating 45 MW-mass zoomed-in halos from the N-body Symphony compilation with embedded disk potentials, which evolve according to star formation histories predicted by the UNIVERSEMACHINE model, we self-consistently tie disk growth to halo accretion rate and significantly expand the range of disk masses and formation histories studied. We use the particle-tracking-based subhalo finder SYMFIND to enhance the robustness of subhalo tracking. We find that disks near the median disk-to-halo mass ratio of our sample (M*,Disk/Mvir,host = 2%) reduce subhalo peak mass functions within 100 kpc by about 10% for peak masses above 108M⊙. Heavier, MW/M31-like disks (M*,Disk/Mvir,host ≳ 5%) lead to a reduction of more than 40%. Subhalo abundance suppression is more pronounced near halo centers, with particularly enhanced stripping for subhalos accreted over 8 Gyr ago on orbits with pericenters &lt;100 kpc. Suppression is further amplified when disk mass is increased within fixed halo and disk assembly histories. In all cases, the suppression we measure should be interpreted as stripping below the mass resolution limit rather than complete subhalo disruption. This study reshapes our understanding of the MW's impact on its satellites, suggesting it strips subhalos more efficiently than typical MW-mass galaxies due to its larger disk-to-halo mass ratio and earlier disk formation.

Keywords: Galaxy dark matter halos, Galaxy formation, N-body simulations
Chemical Abundances of Early Quiescent Galaxies: New Observations and Modeling Impacts. Recent stellar chemical abundance measurements of a handful of z ∼ 2 quiescent galaxies have suggested these galaxies exhibit a remarkably strong α-enhancement compared to their local and intermediate-redshift counterparts. This apparent chemical evolution following quenching suggests that even the innermost regions of massive early-type galaxies may have experienced substantial mixing of stars in mergers, challenging a purely inside-out growth model. However, larger samples are needed to determine whether a high α-enhancement ([Mg/Fe] ≍0.5) is common in z ∼ 2 quiescent galaxies, and a comparative analysis is needed to determine whether it is consistently inferred using different stellar population synthesis models. We report age and stellar chemical abundance measurements for a sample of four gravitationally lensed quiescent galaxies at z ∼ 2.1─2.65 based on Magellan/FIRE spectroscopy. For three of these galaxies we constrain the α-enhancement, and in two cases we measure high values comparable to earlier results when the spectra are analyzed consistently. We also find that the choice of modeling approach can exert a significant effect on the measured abundances. This model dependence can be partly, but not entirely, explained by the complex abundance patterns of α-elements in galaxies, which has been observed at lower redshifts and in one z ∼ 2 quiescent galaxy. Our investigation highlights the importance of independently varying abundance of α-elements when fitting the spectra of such galaxies. Observations with JWST will soon deliver precise and spatially resolved abundances of these and other quiescent galaxies at cosmic noon, opening a new window into their evolution.

Keywords: Abundance ratios, Galaxy chemical evolution, Chemical abundances, Galaxy quenching, Metallicity, Early-type galaxies
X-Ray and Infrared Analysis on a Faint Polar RX J1745.5-2905. RX J1745.5-2905 is a faint and distant polar below the period gap. It was observed intensively in X-ray by Chandra, and its X-ray data reveal frequent brightness transitions between low and high states like we found in the prototype star AM Her. The X-ray radiation is consistent with a typical depiction of magnetic accretion. Although it was detected in X-rays, its counterpart in other bands has not been observed so far. We retrieved all public data and found that Hubble Space Telescope (HST) cached RX J1745.5-2905 in the infrared band (F139M). The infrared photometry confirms its normal behaviors in the low-energy band. Our analysis indicates that the combination of Chandra and HST can help us reach far-distant polars and that the long-term behavior of X-ray sources can help us identify the nature of these sources in the Galactic center.

Keywords: Cataclysmic variable stars, AM Herculis stars, X-ray sources
Origin of the Shell Structure in the Primary Outflow from IRAS 15398‑3359. IRAS 15398‑3359, a Class 0 protostar in the Lupus I star-forming region, is associated with three generations of outflows. The primary outflow, i.e., the most recent one, shows an internal structure named the "shell structure" in the near-infrared emission map. The shell structure is also seen in the emission lines of CO, H2CO, and other species. We find a similar structure in an underexpanded jet produced in aerodynamics and other engineering applications. A high-pressure gas ejected through a nozzle expands to form a supersonic flow. When the pressure of the ejected gas becomes lower than that of the ambient gas, the jet is compressed to form a shock wave. The shock-heated gas expands again to form substructures along the jet. We examine the similarity between the primary outflow of IRAS 15398‑3359 and the industrial underexpanded jet and the possibility that the shell structure of the former is due to repeated expansion and compression in the direction perpendicular to the jet propagation.

Keywords: Protostars, Stellar jets, Star formation
Gravitational Waves from Primordial Black Hole Dark Matter Spikes. The origin of the binary black hole mergers observed by LIGO–Virgo–KAGRA remains an open question. We calculate the merger rate from primordial black holes (PBHs) within the density spike around supermassive black holes (SMBHs) at the centers of galaxies. We show that the merger rate within the spike is comparable to that within the wider dark matter halo. We also calculate the extreme mass ratio inspiral (EMRI) signal from PBHs hosted within the density spike spiralling into their host SMBHs due to gravitational-wave emission. We predict that LISA may detect ∼104 of these EMRIs with a signal-to-noise ratio threshold of 20 within a 4 yr observation run, if all dark matter is made up of ∼30 M⊙ PBHs. Uncertainties in our rates come from the uncertain mass fraction of PBHs within the dark matter spike, relative to the host central SMBHs, which defines the parameter space LISA can constrain.

Keywords: Supermassive black holes, Dark matter, Gravitational waves, Primordial black holes
A New Shock in the Premerging Cluster Pair 1E2215-2216. The galaxy cluster pair 1E2216.0-0401 and 1E2215.7-0404 represents a major cluster merger in its early stages, a phase that has been scarcely explored in previous studies. Within this system, both axial and equatorial merger shocks have been identified. Recent XMM-Newton observations of the southern region of the cluster pair have increased the total exposure time to approximately 300 ks, enhancing the sensitivity to detect faint shock features in the cluster outskirts. Through a combined analysis of XMM-Newton and Chandra data, including both imaging and spectral techniques, a new shock front has been identified at approximately 2 .' 3 south of the X-ray brightness peak of 1E2215. This shock front exhibits a surface brightness ratio of 1.33 ± 0.07 and a temperature ratio of  1.22‑0.14+0.13  in XMM-Newton, consistent with Chandra results. The Mach number, independently calculated from both the temperature and surface brightness discontinuities, yields consistent values of  M≈1.2 . The age, velocity, and spatial distribution of this shock suggest that it shares a common physical origin with the previously identified equatorial shock.

Keywords: X-ray astronomy, Shocks, Galaxy clusters
The Effect of the Fast-flavor Instability on Core-collapse Supernova Models. Merging our supernova code FORNAX with the Box3D fast-flavor neutrino oscillation formalism, we explore the effects of fast-flavor conversion (FFC) in state-of-the-art one-dimensional (1D) and two-dimensional (2D) core-collapse supernova simulations. We find that after a few tens of milliseconds after bounce the FFC emerges just interior and exterior to the stalled shock wave. It does not obtain in the protoneutron star core nor near the average neutrinosphere radii. Interior to the shock, this results in a temporary change in the net neutrino heating rate of ∼10%, due mostly to a hardening of the νe and  ν¯e  neutrino spectra, despite the decrease in their corresponding neutrino number fluxes. In 1D, the hydrodynamic effects are not large, with increases in the stalled shock radius by of order 10 to 20 km that abate within a few hundred milliseconds. In 2D, the hydrodynamic effect of the FFC is a bit more noticeable, resulting in slightly earlier explosions for models for lower-mass progenitors but also potentially inhibiting explosions for some higher-mass progenitors. FFC continues to operate at larger radii at later times. The net result is a shift upward in the νμ energy and number luminosities and a shift downward in the same quantities for both the νe and  ν¯e  neutrinos. There seems to be a trend at very large radii and later times toward partial species and spectral equipartition. If this is true, it could be an interesting feature of supernova neutrino detection at later times in underground and under-ice facilities.

Keywords: Neutrino oscillations, Supernova neutrinos, Core-collapse supernovae
Magnetic Flux Transport Signatures of Electron-only and Ion-coupled Magnetic Reconnection in Plasma Turbulence. Electron-only magnetic reconnection was first detected by the Magnetospheric Multiscale (MMS) mission in Earth's turbulent magnetosheath. Its prevalence in kinetic-scale turbulence has attracted great interest in heliophysics, but also revealed a great challenge in identifying it in turbulence, where electron flows are often complex. The magnetic flux transport (MFT) method is an innovative method to identify active reconnection in numerical simulations and in situ observations of turbulent plasmas. Here we extend this method to distinguish between electron-only and ion-coupled reconnection. The coupling of magnetic field motion with plasma flows in the diffusion regions sets distinct scales in the MFT velocity. While both forms of reconnection satisfy the MFT signature for active reconnection as MFT inflows and outflows at an X-line, the specific electron-only MFT signature is only an electron-scale MFT outflow along the current sheet normal direction, whereas the specific ion-coupled signature is a two-scale, outer-ion-and-inner-electron-scale MFT outflow in the electron diffusion region, which evolves into a single ion-scale in the ion diffusion region. These signatures are verified in a simulation of gyrokinetic turbulence. The dependence of the MFT outflow on the distance downstream from the X-lines also agrees well with the framework of magnetic field–plasma flow coupling. The new MFT signatures provide a clear and reliable tool for investigating electron-only reconnection in turbulence, independent of the development of electron outflows. They are directly applicable to kinetic and fluid simulations, and have potential application to observations of diffusion region crossings by spacecraft missions such as MMS.

Keywords: Interplanetary turbulence, Solar magnetic reconnection
Detection of Intermediate-mass Ratio Inspirals in Globular Clusters: Revealing the Brownian Motion with Gravitational Waves. Intermediate-mass ratio inspirals (IMRIs) formed by stellar-mass compact objects orbiting intermediate-mass black holes will be detected by future gravitational wave (GW) observatories like TianQin, LISA, and AION. We study a set of 100 IMRI systems in globular clusters obtained from MOCCA simulations to estimate their detectability. Furthermore, we model the Brownian motion of the IMRIs induced by weak interactions with the surrounding field of stars and include its effect on the GW's phase through Doppler and aberrational phase shift. We find that a small fraction of IMRIs (&lt;10%) will have signal-to-noise ratios (SNRs) high enough to be detected by TianQin, LISA, and AION. However, for all sources detected, the SNR is high enough to discern the Brownian motion of the IMRI. More precisely, we find that the match between the signal containing the effect of the Brownian motion and a waveform model without this effect is mostly low (&lt;0.8). These results highlight the importance of including the interaction of IMRIs with the surrounding field of stars to obtain proper detection, but also show the possibility of studying the environment of the source using GWs.

Keywords: Intermediate-mass black holes, Gravitational wave sources, Gravitational interaction, Gravitational wave astronomy, Star clusters