Sazuna/UAT_keywords huggingface dataset:
Studying Magnetic Reconnection with Synchrotron Polarization Statistics. Magnetic reconnection is a fundamental process for releasing magnetic energy in space physics and astrophysics. At present, the usual way to investigate the reconnection process is through analytical studies or first-principle numerical simulations. This paper is the first to understand the turbulent magnetic reconnection process by exploring the nature of magnetic turbulence. From the perspective of radio synchrotron polarization statistics, we study how to recover the properties of the turbulent magnetic field by considering the line of sight along different directions of the reconnection layer. We find that polarization intensity statistics can reveal the spectral properties of reconnection turbulence. This work opens up a new way of understanding turbulent magnetic reconnection.

Keywords: Magnetohydrodynamics, Interplanetary turbulence, Computational methods, Interstellar medium, Magnetohydrodynamical simulations
The Long-period Spectroscopic Orbit and Dust Creation in the Wolf─Rayet Binary System WR 125. Several long-period binaries with a carbon-rich Wolf─Rayet star and an OB star produce dust in their wind collisions. In eccentric binaries, this is seen most strongly near periastron passage. The exact conditions leading to dust creation require the orbital properties to be determined, which is difficult owing to their long periods. Recently, the binary system WR 125 (WC7 + O9III) began a dust-creation episode seen through an infrared outburst first detected by NEOWISE-R, which was the first outburst detected since 1991. We present new near- and mid-infrared photometry, which we use to show consistency between the two outbursts and derive an orbital period of  28.12−0.05+0.10  yr. We use a long time series of optical spectra to place the first constraints on its orbital elements, on the assumption that this system will produce dust near periastron. The orbit has a mild eccentricity of 0.29 ± 0.12 and is only derived for the Wolf─Rayet component, as the O star's radial velocities have noise that is likely larger than the expected semiamplitude of the orbit. We also present SOFIA/FORCAST grism spectroscopy to examine the infrared spectral energy distribution of the dust during this outburst, comparing its properties to other WCd binaries, and deriving a dust temperature of 580 K in 2021. This collection of observations will allow us to plan future observations of this system and place the system in the context of dust-creating Wolf─Rayet binaries.

Keywords: Wolf-Rayet stars, WC stars, Binary stars, Spectroscopic binary stars
Nucleosynthesis in the Innermost Ejecta of Magnetorotational Supernova Explosions in Three Dimensions. Core-collapse supernova (CCSN) explosions powered by rotation and magnetic fields present an interesting astrophysical site for nucleosynthesis that potentially contributes to the production of r-process elements. Here we present yields of the innermost ejecta in 3D magnetorotational CCSN models simulated using the COCONUT-FMT code. Strong magnetic fields tap the rotational energy of the proto‑neutron star and lead to earlier and more energetic (∼3 × 1051 erg) explosions than typical neutrino-driven CCSNe. Compared to a reference nonmagnetic model, the ejecta in the magnetorotational models have much more neutron-rich components with Y  e  down to ∼0.25. Our post-processing calculations with the reaction network SkyNet show significant production of weak r-process elements up to mass number ∼130. We find negligible differences in the synthesis of heavy elements between two magnetorotational models with different initial field strengths of 1010 and 1012 G, in accord with their similar explosion dynamics. The magnetorotational models produce about ∼0.19 and 0.14 M ☉ of radioactive 56Ni, on the low end of inferred hypernova nickel masses. The yields are publicly available at Zenodo (doi: 10.5281/zenodo.10578981) for comparison with stellar abundance patterns, inclusion in modeling galactic chemical evolution, and comparison with other yield calculations. Our results add to the yet-restricted corpus of nucleosynthesis yields from 3D magnetorotational supernova simulations and will help quantify yield uncertainties.

Keywords: Magnetohydrodynamics, Nucleosynthesis, Core-collapse supernovae, R-process
Formation Channels of Diffuse Lights in Groups and Clusters over Time. We explore the formation of the intragroup light and intracluster light, representing diffuse lights within groups and clusters, from the point that z = 1.5. For this, we perform multiresolution cosmological N-body simulations using the "galaxy replacement technique" and identify the progenitors in which the diffuse light stars existed when they fell into the groups or clusters. Our findings reveal that typical progenitors contributing to diffuse lights enter the host halo with massive galaxies containing a stellar mass of  10&lt;logMgal[M⊙]&lt;11 , regardless of the mass or dynamical state of the host halos at z = 0. In cases where the host halos are dynamically unrelaxed or more massive, diffuse lights from massive progenitors with  logMgal[M⊙]&gt;11  are more prominent, with over half of them already preprocessed before entering the host halo. Additionally, we find that the main formation mechanism of diffuse lights is the stripping process of satellites, and a substantial fraction (40%–45%) of diffuse light stars are linked to the merger tree of the brightest cluster galaxy. Remarkably, all trends persist for groups and clusters at higher redshifts. The fraction of diffuse lights in the host halos with a similar mass decreases as the redshift increases, but they are already substantial at z = 1.5 (∼10%). However, it is crucial to acknowledge that detection limits related to the observable radius and faint-end surface brightness may obscure numerous diffuse light stars and even alter the main formation channel of diffuse lights.

Keywords: Galaxy clusters, Galaxy formation, Galaxy evolution, Computational methods
A Radial Decrease in Kinetic Temperature Measured with H<SUB>2</SUB>CO in 30 Doradus. Feedback from star formation is a critical component of the evolution of galaxies and their interstellar medium. At parsec scales internal to molecular clouds, however, the observed signatures of that feedback on the physical properties of CO-emitting gas have often been weak or inconclusive. We present subparsec observations of H2CO in the 30 Doradus region, which contains the massive star cluster R136 that is clearly exerting feedback on its neighboring gas. H2CO provides a direct measure of gas kinetic temperature, and we find a trend of decreasing temperature with projected distance from R136 that may be indicative of gas heating by the stars. While it has been suggested that mechanical heating affects H2CO-measured temperature, we do not observe any correlation between T  K  and line width. The lack of an enhancement in mechanical feedback close to R136 is consistent with the absence of a radial trend in gravitational boundedness seen the Atacama Large Millimeter/submillimeter Array CO observations. Estimates of cosmic-ray flux in the region are quite uncertain, but can plausibly explain the observed temperatures if R136 itself is the dominant local source of energetic protons. The observations presented here are also consistent with the H2CO-emitting gas near R136 being dominated by direct radiation from R136 and photoelectric heating in the photodissociation regions.

Keywords: Interstellar molecules, Stellar feedback, Molecular clouds, Star formation, H II regions
GAINN: The Galaxy Assembly and Interaction Neural Networks for High-redshift JWST Observations. We present the Galaxy Assembly and Interaction Neural Networks (GAINN), a series of artificial neural networks for predicting the redshift, stellar mass, halo mass, and mass-weighted age of simulated galaxies based on James Webb Space Telescope (JWST) photometry. Our goal is to determine the best neural network for predicting these variables at 11 &lt; z &lt; 15. The parameters of the optimal neural network can then be used to estimate these variables for real, observed galaxies. The inputs of the neural networks are JWST filter magnitudes of a subset of five broadband filters (F150W, F200W, F277W, F356W, and F444W) and two medium-band filters (F162M and F182M). We compare the performance of the neural networks using different combinations of these filters, as well as different activation functions and numbers of layers. The best neural network predicted redshift with a normalized rms error of  0.010‑0.001+0.003 , stellar mass with rms =  0.089‑0.022+0.044 , halo mass with a mean-squared error of  0.022‑0.008+0.014 , and mass-weighted age with rms =  12.466‑2.408+5.065 . We also test the performance of GAINN on real data from MACS0647JD, an object observed by JWST. Predictions from GAINN for the first projection of the object (JD1) have normalized bias 〈Δz〉 &lt; 0.00228, which is significantly smaller than found with template-fitting methods. We find that the optimal filter combination is F277W, F356W, F162M, and F200W when considering both theoretical accuracy and observational resources from JWST.

Keywords: Hydrodynamical simulations, Galaxy properties, Neural networks, James Webb Space Telescope, High-redshift galaxies
Updating the First CHIME/FRB Catalog of Fast Radio Bursts with Baseband Data. In 2021, a catalog of 536 fast radio bursts (FRBs) detected with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope was released by the CHIME/FRB Collaboration. This large collection of bursts, observed with a single instrument and uniform selection effects, has advanced our understanding of the FRB population. Here we update the results for 140 of these FRBs for which channelized raw voltage ("baseband") data are available. With the voltages measured by the telescope's antennas, it is possible to maximize the telescope sensitivity in any direction within the primary beam, an operation called "beamforming." This allows us to increase the signal-to-noise ratios of the bursts and to localize them to subarcminute precision. The improved localizations are also used to correct the beam response of the instrument and to measure fluxes and fluences with an ∼10% uncertainty. Additionally, the time resolution is increased by 3 orders of magnitude relative to that in the first CHIME/FRB catalog, and, applying coherent dedispersion, burst morphologies can be studied in detail. Polarization information is also available for the full sample of 140 FRBs, providing an unprecedented data set to study the polarization properties of the population. We release the baseband data beamformed to the most probable position of each FRB. These data are analyzed in detail in a series of accompanying papers.

Keywords: Radio source catalogs, Extragalactic radio sources, Radio bursts, Radio telescopes, Radio astronomy, Radio sources, Radio transient sources
A Possibly Short GRB 180418A and Phenomenology of Reverse-Shock Emission in the Optical Afterglows of Gamma-Ray Bursts. We present early-time ground-based optical follow-up observations of GRB 180418A, which was discovered by both Swift/BAT and Fermi/GBM. Its broadband afterglow was well monitored by Swift/XRT and ground-based optical telescopes. The optical light curve of GRB 180418A can be modeled by forward shock (FS) plus reverse shock (RS). We fit the light curves with standard external shock models and derive the physical properties of the outflow. It is found that the ratio R  B  ≡ ɛ  B,r /ɛ  B,f  is 11.22, indicating a moderate degree of magnetization in the RS region. The reported duration of GRB 180418A, T 90, lies in the intermediate region between short and long gamma-ray bursts (GRBs). We further discuss the classification of GRB 180418A, and calculate ɛ = E  γ,iso,52/E  p,z,2 values of 0.026 and 0.018 (assuming the redshift z is 1.0 and 1.5, respectively), which is closer to short GRBs (SGRBs) in the ɛ-T 90,z  plane. If GRB 180418A is an SGRB, it is the only reported SGRB thus far with RS emission in optical light curves. In order to compare the properties of GRB 180418A, we collected three SGRBs that may have RS emission (GRBs 060313, 090426, and 210207B) and also 22 long GRBs (LGRBs) with RS emission. We find that the parameters of LGRBs are in a wider range than those of SGRBs. Also, SGRBs appear to have very small R  B  values, but the results are generally similar to those of LGRBs. The fitting parameters of GRB 180418A are generally consistent with those of the other three SGRBs, implying that GRB 180418A may belong to the category of SGRBs.

Keywords: Gamma-ray bursts
Exploring the Effects of Stellar Magnetism on the Potential Habitability of Exoplanets. Considerable interest has centered on Earth-like planets orbiting in the circumstellar habitable zone (CHZ) of its star. However, the potential habitability of an exoplanet depends upon a number of additional factors, including the presence and strength of any planetary magnetic field and the interaction of this field with that of the host star. Not only must the exoplanet have a strong enough magnetic field to shield against stellar activity, but it must also orbit far enough from the star to avoid direct magnetic connectivity. We characterize stellar activity by the star's Rossby number, Ro, the ratio of stellar rotation rate to convective turnover time. We employ a scaled model of the solar magnetic field to determine the star's Alfvén radius, the distance at which the stellar wind becomes super-Alfvénic. Planets residing within the Alfvén surface may have a direct magnetic connection to the star and therefore not be the most viable candidates for habitability. Here, we determine the Rossby number of a sample of 1053 exoplanet-hosting stars for which the rotation rates have been observed and for which a convective turnover time can be calculated. We find that 84 exoplanets in our sample have orbits which lie inside the CHZ and that also lie outside the star's Alfvén surface: 34 of these have been classified as terran (11) or superterran (23) planets. Applying the Alfvén surface habitability criterion yields a subset of the confirmed exoplanets that may be optimal targets for future observations in the search for signatures of life.

Keywords: Exoplanets, Space weather, Solar wind, Solar-planetary interactions, Stellar magnetic fields, Stellar activity, Stellar winds, Interplanetary magnetic fields, Solar magnetic fields, Solar activity, Star-planet interactions, Habitable planets
A Comprehensive Metallicity Analysis of J0332−3557: Establishing a z ∼ 4 Anchor for Direct Gas Metallicity and C/O Abundance Investigations. We provide one of the most comprehensive metallicity studies at z ∼ 4 by analyzing the UV/optical Hubble Space Telescope photometry and rest-frame Very Large Telescope (VLT)/FORS2 UV and VLT/XSHOOTER optical spectra of J0332−3557, a gravitationally lensed galaxy magnified by a factor of 20. With a 5σ detection of the auroral O III] λ1666 line, we are able to derive a direct gas metallicity estimate for our target. We find Z gas  =12+log(O/H)=8.26±0.06 , which is compatible with an increase of both the gas fraction and the outflow metal loading factor from z ∼ 0 to z ∼ 4. J0332−3557 is the most metal-rich individual galaxy at z ∼ 4 for which the C/O ratio has been measured. We derive a low log(C/O) = −1.02 ± 0.2, which suggests that J0332−3557 is in the early stages of interstellar medium carbon enrichment driven mostly by massive stars. The low C/O abundance also indicates that J0332−3557 is characterized by a low star formation efficiency, higher yields of oxygen, and longer burst duration. We find that EWC III]1906,9 is as low as ∼3 Å, and the main drivers of the low EWC III]1906,9 are the higher gas metallicity and the low C/O abundance. J0332−3557 is characterized by one diffuse and two more compact regions ∼1 kpc in size. We find that the carbon emission mostly originates in the compact knots. Our study on J0332−3557 serves as an anchor for studies investigating the evolution of metallicity and C/O abundance across different redshifts.

Keywords: Strong gravitational lensing, High-redshift galaxies, Galaxy evolution
Photons from Neutrinos: The Gamma-Ray Echo of a Supernova Neutrino Burst. When a star undergoes core collapse, a vast amount of energy is released in a ∼10 s long burst of neutrinos of all species. Inverse beta decay in the star's hydrogen envelope causes an electromagnetic cascade that ultimately results in a flare of gamma rays—an "echo" of the neutrino burst—at the characteristic energy of 0.511 MeV. We study the phenomenology and detectability of this flare. Its luminosity curve is characterized by a fast, seconds-long rise and an equally fast decline, with a minute- or hour-long plateau in between. For a near-Earth star (distance D ≲ 1 kpc) the echo will be observable at near future gamma-ray telescopes with an effective area of 103 cm2 or larger. Its observation will inform us on the envelope size and composition. In conjunction with the direct detection of the neutrino burst, it will also give information on the neutrino emission away from the line of sight and will enable tests of neutrino propagation effects between the stellar surface and Earth.

Keywords: Supernova neutrinos, Gamma-rays, Core-collapse supernovae
SOFIA/HAWC+ Far-infrared Polarimetric Large-area CMZ Exploration Survey. III. Full Survey Data Set. We present the second data release (DR2) of the Far-InfraREd Polarimetric Large-Area CMZ Exploration (FIREPLACE) survey. This survey utilized the Stratospheric Observatory for Infrared Astronomy High-resolution Airborne Wideband Camera plus instrument at 214 μm (E band) at a resolution of 19.″6 to observe thermal polarized dust emission throughout the Central Molecular Zone (CMZ). DR2 consists of observations obtained in 2022 covering the region of the CMZ extending from the Brick to the Sgr C molecular clouds (corresponding to a 1° × 0.°75 region of the sky). We combine DR2 with the first FIREPLACE data release (DR1) to obtain full coverage of the CMZ (a 1.°5 × 0.°75 region of the sky). After applying total and polarized intensity significance cuts on the full FIREPLACE data set, we obtain ∼64,000 Nyquist-sampled polarization pseudovectors. The distribution of polarization pseudovectors confirms a bimodal distribution in the CMZ magnetic field orientations, recovering field components that are oriented predominantly parallel or perpendicular to the Galactic plane. This distribution of orientations is similar to what was observed in DR1 and other studies. We also inspect the magnetic fields toward a set of prominent CMZ molecular clouds (the Brick, Three Little Pigs, 50 and 20 km s‑1 clouds, circumnuclear disk, CO 0.02-0.02, and Sgr C), revealing spatially varying magnetic fields having orientations that generally trace the total intensity morphologies of the clouds. We find evidence that compression from stellar winds and shear from tidal forces are prominent mechanisms influencing the structure of the magnetic fields.

Keywords: Galactic center, Molecular clouds, Interstellar medium
A Strong Falsification of the Universal Radial Acceleration Relation in Galaxies. In the past few decades, many studies revealed that there exist some apparent universal relations that can describe the dynamical properties in galaxies. In particular, the radial acceleration relation (RAR) is one of the most popular relations discovered recently that can be regarded as a universal law to connect the dynamical radial acceleration with the baryonic acceleration in galaxies. This has revealed an unexpected close connection between dark matter and baryonic matter in galaxies. In this article, by following the recent robust Galactic rotation curve analyzes, we derive the Galactic RAR (GRAR) and show for the first time that the alleged best-fit universal RAR deviates from the GRAR data at more than 5σ. This provides a strong evidence to falsify the universal nature of RAR in galaxies claimed in past studies.

Keywords: Galaxy dark matter halos, Galaxy dynamics
An Atypical Low-frequency Quasiperiodic Oscillation Detected in the Hard State of MAXI J1348–630 with Insight-HXMT. Based on the Insight-HXMT archival data, we have detected a new atypical low-frequency quasiperiodic oscillation (LFQPO) in the black hole X-ray binary MAXI J1348‑630. The new LFQPO is detected in all three instruments of Insight-HXMT with a combined significance of 3σ–5σ, covering a wide energy range of 1–100 keV. The fractional rms seems to decrease with energy. It exclusively appears in the hard state during both the main and mini outburst, spanning an X-ray intensity range by a factor of 10, and a very narrow hardness range. The frequency of this new type of LFQPO is moderately stable, in the range of 0.08–0.15 Hz. We discussed different models for the LFQPO, and found none can explain the observed properties of this new type of LFQPO.

Keywords: Stellar accretion disks, X-ray binary stars
Periodically Modulated Magnetic Reconnection. We present the first evidence for periodically modulated reconnection at the electron scale in space, using unparalleled, high-cadence data from Magnetospheric Multiscale spacecraft. The periodic modulation is attributed to finite magnetic trapping imposed by the X-line, which generates discrete, dispersive electron stripes. The dispersive stripes, well reproduced by a trapping-loss transition model, periodically break the frozen-in condition and drive energy dissipation. Such an electron transition effect eliminates free electrons, enhances electron mixing, and causes highly structured, three-dimensional distributions that generate intense radio emissions. These illuminating results, suggesting that reconnection hosts inherent periodicity determined by three-dimensional electron physics, provide crucial insights into understanding reconnection-driven energy transport in space and astrophysical plasmas.

Keywords: Space plasmas
The Effects of Including Farside Observations on In Situ Predictions of Heliospheric Models. A significant challenge facing heliospheric models is the lack of full Sun observational coverage. The lack of information about the farside photospheric magnetic field necessitates the use of various techniques to approximate the structure and appearance of this field. However, a recently developed technique that uses He II 304 Å emission observed by the Solar Terrestrial Relations Observatory (STEREO) enables developing a magnetic flux proxy by imaging of active regions on the far side of the Sun. Incorporating information about these active regions on the far side of the Sun may have the potential to drastically improve heliospheric models. In this work, we run multiple heliospheric models with and without farside information obtained from STEREO observations of He II 304 Å emission and compare the predicted in situ measurements from the models with real in situ data from STEREO and Earth. We find that although there are noticeable quantitative differences between the in situ predictions from the two models, they are dwarfed by the overall disagreement between the heliospheric model and the actual in situ data. Nevertheless, our results indicate that active regions that significantly change the ratio of open-to-closed and open-to-total flux create the biggest change in the predicted in situ measurements.

Keywords: Solar wind, Heliosphere