Sazuna/UAT_keywords huggingface dataset:
A Study of Slow-mode Shocks in the Near-Earth Magnetotail with MMS Observations and Hybrid Simulations. The structure of the magnetic reconnection boundary, particularly the presence of slow-mode shocks in the near-Earth magnetotail was studied by using magnetospheric multiscale (MMS) observations and 2.5D hybrid simulations. A total of 51 crossings of MMS from 2017 to 2021 were analyzed. We found that the detection percentage of slow-mode shocks in the near-Earth magnetotail is 41%–55%. Previous studies have only reported one slow-mode shock event in the near-Earth magnetotail and a slow-mode shock detection percentage of 10% or lower in the mid-to-distant magnetotail. It was observed that if the high-energy beam region data is removed from the slow-mode shock downstream observations then the detection of slow-mode shocks reduces, implying that the kinetic effects play an important role in the detection of slow-mode shocks. For the crossings where the interface was not identified as a slow-mode shock, it was found that the turbulence in those crossings can change the mass flux values and disrupt the detection of slow-mode shock. However, the macroscopic slow-mode shock-like structure stably exists around the magnetic reconnection interface, as most of the conditions for slow-mode shocks were satisfied. This result suggests that slow-mode shocks are a general feature of magnetic reconnection geometry. We find that the lack of detection of slow-mode shocks in previous observations and simulations can be explained by taking into account the kinetic structure of slow-mode shocks and the presence of turbulence.

Keywords: Shocks, Planetary magnetospheres, Space plasmas
Constraining the Circumstellar Medium Structure and Progenitor Mass-loss History of Interacting Supernovae Through 3D Hydrodynamic Modeling: The Case of SN 2014C. We investigate SN 2014C using three-dimensional (3D) hydrodynamic modeling, focusing on its early interaction with a dense circumstellar medium (CSM). Our objective is to uncover the pre-supernova (SN) CSM structure and constrain the progenitor star's mass-loss history prior to core collapse. Our comprehensive model traces the evolution from the progenitor star through the SN event and into the SN remnant phase. We simulate the remnant's expansion over approximately 15 yr, incorporating a CSM derived from the progenitor star's outflows through dedicated hydrodynamic simulations. Analysis reveals that the remnant interacted with a dense toroidal nebula extending from 4.3 × 1016 to 1.5 × 1017 cm in the equatorial plane, with a thickness of approximately 1.2 × 1017 cm. The nebula's density peaks at approximately 3 × 106 cm‑3 at the inner boundary, gradually decreasing as ≈r ‑2 at greater distances. This nebula formed due to intense mass loss from the progenitor star between approximately 5000 and 1000 yr before collapse. During this period, the maximum mass-loss rate reached about 8 × 10‑4 M ⊙ yr‑1, ejecting ≈2.5 M ⊙ of stellar material into the CSM. Our model accurately reproduces Chandra and NuSTAR spectra, including the iron (Fe) K line, throughout the remnant's evolution. Notably, the Fe line is self-consistently reproduced, originating from shocked ejecta, with ≈0.05 M ⊙ of pure-Fe ejecta shocked during the remnant–nebula interaction. These findings suggest that the 3D geometry and density distribution of the CSM, as well as the progenitor star's mass-loss history, align with a scenario where the star was stripped through binary interaction, specifically common-envelope evolution.

Keywords: High energy astrophysics, Core-collapse supernovae, Supernova remnants, Supernovae, Common envelope evolution, Supernova dynamics
ODIN: Identifying Protoclusters and Cosmic Filaments Traced by Lyα-emitting Galaxies. To understand the formation and evolution of massive cosmic structures, studying them at high redshift, in the epoch when they formed the majority of their mass, is essential. The One-hundred-deg2 DECam Imaging in Narrowbands (ODIN) survey is undertaking the widest-area narrowband program to date, to use Lyα-emitting galaxies (LAEs) to trace the large-scale structure (LSS) of the Universe on the scale of 10–100 cMpc at three cosmic epochs. In this work, we present results at z = 3.1 based on early ODIN data in the COSMOS field. We identify protoclusters and cosmic filaments using multiple methods and discuss their strengths and weaknesses. We then compare our observations against the IllustrisTNG suite of cosmological hydrodynamical simulations. The two are in excellent agreement, identifying a similar number and angular size of structures above a specified density threshold. We successfully recover the simulated protoclusters with log(M  z=0/M ⊙) ≳ 14.4 in ∼60% of the cases. With these objects, we show that the descendant masses of our observed protoclusters can be estimated purely based on our 2D measurements, finding a median z = 0 mass of ∼1014.5 M ⊙. The lack of information on the radial extent of each protocluster introduces a ∼0.4 dex uncertainty in its descendant mass. Finally, we show that the recovery of the cosmic web in the vicinity of protoclusters is both efficient and accurate. The similarity of our observations and the simulations implies that our structure selection is likewise robust and efficient, demonstrating that LAEs are reliable tracers of the LSS.

Keywords: Large-scale structure of the universe, Lyman-alpha galaxies, High-redshift galaxy clusters
JWST Validates HST Distance Measurements: Selection of Supernova Subsample Explains Differences in JWST Estimates of Local H <SUB>0</SUB>. We cross-check the Hubble Space Telescope (HST) Cepheid/Type Ia supernova (SN Ia) distance ladder, which yields the most precise local H 0, against early James Webb Space Telescope (JWST) subsamples (∼1/4 of the HST sample) from SH0ES and CCHP, calibrated only with NGC 4258. We find HST Cepheid distances agree well (∼1σ) with all combinations of methods, samples, and telescopes. The comparisons explicitly include the measurement uncertainty of each method in NGC 4258, an oft-neglected but dominant term. Mean differences are ∼0.03 mag, far smaller than the 0.18 mag "Hubble tension." Combining all measures produces the strongest constraint yet on the linearity of HST Cepheid distances, 0.994 ±0.010, ruling out distance-dependent bias or offset as the source of the tension at ∼7σ. However, current JWST subsamples produce large sampling differences in H0 whose size and direction we can directly estimate from the full HST set. We show that ΔH 0 ∼ 2.5 km s‑1 Mpc‑1 between the CCHP JWST program and the full HST sample is entirely consistent with differences in sample selection. We combine all JWST samples into a new distance-limited set of 16 SNe Ia at D ≤ 25 Mpc. Using JWST Cepheids, JAGB, and tip of the red giant branch, we find 73.4 ± 2.1, 72.2 ± 2.2, and 72.1 ± 2.2 km s‑1 Mpc‑1, respectively. Explicitly accounting for common supernovae, the three-method JWST result is H 0 = 72.6 ± 2.0, similar to H 0 = 72.8 expected from HST Cepheids in the same galaxies. The small JWST sample trivially lowers the Hubble tension significance due to small-sample statistics and is not yet competitive with the HST set (42 SNe Ia and 4 anchors), which yields 73.2 ± 0.9. Still, the joint JWST sample provides important cross-checks that the HST data pass.

Keywords: Cosmological parameters, Distance indicators, Hubble constant, James Webb Space Telescope, Cepheid distance
Exploring Magnetic Fields in a Merging Galaxy: Comparing Polarization and Velocity Gradient in the Centaurus Galaxy. In this study, we apply the velocity gradient technique to the merging Centaurus galaxy. We compare gradient maps derived from the PHANGS-Atacama Large Millimeter/submillimeter Array survey using CO emission lines with magnetic field tracings from dust polarization data obtained via the HAWC+ instrument. Our analysis reveals a strong correspondence between the directions indicated by these two tracers across most of the galactic image. Specifically, we identify jet regions as areas of antialignment, consistent with previous reports that gradients tend to rotate 90° in outflow regions. Statistically, we find that the alignment of magnetic fields, as revealed by polarization, is most accurate in regions with the highest signal-to-noise ratios. Our findings underscore the utility of velocity gradients as a valuable complementary tool for probing magnetic fields and dynamical processes in merging galaxies. This proves the general utility of velocity gradients for mapping magnetic fields in astrophysical objects with complex dynamics.

Keywords: Galaxy nuclei, Interstellar medium, Extragalactic magnetic fields
Challenges for Fast Radio Bursts as Multimessenger Sources from Binary Neutron Star Mergers. Fast radio bursts (FRBs) are millisecond-duration transients from extragalactic sources, with their origins remaining a topic of active debate. Among the proposed progenitors, binary neutron star (BNS) mergers are compelling candidates for some nonrepeating FRBs. However, associating FRBs with BNS mergers cannot be based solely on low chance coincidence probability. This study delineates necessary criteria for associating FRBs with BNS mergers, focusing on the postmerger ejecta environment. To underscore the significance of these criteria, we scrutinise the proposed association between GW190425 and FRB 20190425A, considering the requirement for the FRB signal to traverse the dense merger ejecta without significant attenuation to remain detectable at 400 MHz. Our investigation reveals that if the FRB is linked to the gravitational-wave (GW) event, the GW data support a highly off-axis configuration, with a probability of the BNS merger viewing angle p(θ  v  &gt; 30°) being ≈99.99%. This strongly excludes an on-axis system, which is required for this FRB to be detectable. We also find faraway FRB emission models inadequate to explain the FRB 20190425A–GW190425 connection. Thus, we conclude that GW190425 is not related to FRB 20190425A. We discuss the implications for future multimessenger observations, suggesting that BNS merger remnants are unlikely to account for more than 1% of FRB sources. This finding implies that short gamma-ray bursts, which are expected to occur in only a fraction of all BNS mergers, cannot account for the overall characteristics of the FRB host population.

Keywords: Radio pulsars, Radio transient sources
Reverse Shock Emission from Misaligned Structured Jets in Gamma-Ray Bursts. The afterglow of gamma-ray bursts (GRBs) has been extensively discussed in the context of shocks generated during an interaction of relativistic outflows with their ambient medium. This process leads to the formation of both a forward and a reverse shock. While the emission from the forward shock, observed off-axis, has been well-studied as a potential electromagnetic counterpart to a gravitational-wave-detected merger, the contribution of the reverse shock is commonly overlooked. In this paper, we investigate the contribution of the reverse shock to the GRB afterglows observed off-axis. In our analysis, we consider jets with different angular profiles, including two-component jets, power-law structured jets, Gaussian jets, and "mixed jets" featuring a Poynting-flux-dominated core surrounded by a baryonic wing. We apply our model to GRB 170817A/GW170817 and employ the Markov Chain Monte Carlo method to obtain model parameters. Our findings suggest that the reverse shock emission can significantly contribute to the early afterglow. In addition, our calculations indicate that the light curves observable in future off-axis GRBs may exhibit either double peaks or a single peak with a prominent feature, depending on the jet structure, viewing angle, and microphysics shock parameters.

Keywords: Non-thermal radiation sources, Gamma-ray bursts, Relativistic jets
Detailed Calculations of the Efficiency of Planetesimal Accretion in the Core-accretion Model. III. The Contribution of Planetesimals beyond Saturn. Continuing our initiative on advancing the calculations of planetesimal accretion in the core-accretion model, we present here the results of our recent study of the contributions of planetesimals around and beyond the orbit of Saturn. In our first two papers, where our focus was on the effects of the Sun and Saturn, the initial distribution of planetesimals was limited to the regions around the accretion zone of a growing Jupiter. In this paper, we expanded that distribution to regions beyond the accretion zone of Saturn. We integrated the orbits of a large ensemble of planetesimals and studied the rate of their capture by the growing proto-Jupiter. In order to be consistent with our previous studies, we did not consider the effect of the nebular gas. Results demonstrated that the exterior planetesimals, especially those beyond 8 au, have only slight contributions to the growth and metallicity of the growing Jupiter. The final mass and composition of this planet is mainly due to the planetesimals inside and around its accretion zone. Our study shows that although the rate of capture varies slightly by the size and composition of planetesimals, in general, the final results are independent of the size and material of these bodies. Results also pointed to a new finding: the rate of accretion follows the same trend as that of the evolution of Jupiter's envelope, with the largest accretion occurring during the envelope's collapse. We present details of our analysis and discuss the implications of its results.

Keywords: Jupiter, Solar system gas giant planets, Planet formation, Planetesimals
Mergers, Radio Jets, and Quenching Star Formation in Massive Galaxies: Quantifying Their Synchronized Cosmic Evolution and Assessing the Energetics. The existence of a population of massive quiescent galaxies with little to no star formation poses a challenge to our understanding of galaxy evolution. The physical process that quenched the star formation in these galaxies is debated, but the most popular possibility is that feedback from supermassive black holes lifts or heats the gas that would otherwise be used to form stars. In this paper, we evaluate this idea in two ways. First, we compare the cumulative growth in the cosmic inventory of the total stellar mass in quiescent galaxies to the corresponding growth in the amount of kinetic energy carried by radio jets. We find that these two inventories are remarkably well-synchronized, with about 50% of the total amounts being created in the epoch from z ≈ 1 to 2. We also show that these agree extremely well with the corresponding growth in the cumulative number of major mergers that result in massive (&gt;1011 M ʘ) galaxies. We therefore argue that major mergers trigger the radio jets and also transform the galaxies from disks to spheroids. Second, we evaluate the total amount of kinetic energy delivered by jets and compare it to the baryonic binding energy of the galaxies. We find the jet kinetic energy is more than sufficient to quench star formation, and the quenching process should be more effective in more massive galaxies. We show that these results are quantitatively consistent with recent measurements of the Sunyaev–Zel'dovich effect seen in massive galaxies at z ≈ 1.

Keywords: Radio jets, Galaxy evolution
Multiple Components of the Outflow in the Protostellar System HH 212: Outer Outflow Shell, Rotating Wind, Shocked Wind, and Jet. We present the Atacama Large Millimeter/submillimeter Array Band 7 observations of the CO (J = 3−2) line emission of the protostellar system HH 212 at ∼24 au spatial resolution and compare them to those of the SiO (J = 8−7) and SO (J = 8−7) line emission reported in the literature. We find that the CO line traces four distinct regions: (1) an outer outflow shell, (2) a rotating wind region between the SiO and CO shells, (3) the shocked and wide-angle inner X-wind inside a SiO shell, and (4) the jet. The origin of the CO outer outflow shell could be associated with the entrained material of the envelope, or an extended disk wind. The rotating wind, which is shocked, is launched from a radius of 9─15 au, slightly exterior to that of the previously detected SO shell, which marks the boundary where the wide-angle X-wind is interacting with and shocking the disk wind. Additionally, the SO is found to be mixed with the CO emission within the thick and extended rotating wind region. The large-scale CO-shocked wind coexists with the SO emission near the upper portion of the inner shocked region converged on top of the inner SiO knots. The CO jet is traced by a chain of knots with roughly equal intervals, exhibiting quasiperiodicity, as reported in other jets in the literature.

Keywords: Accretion, Herbig-Haro objects, Stellar jets, Stellar winds, Young stellar objects, Star formation
Dynamic 3D Simulation of Surface Charging on Rotating Asteroids. The surface-charging phenomenon of asteroids, mainly resulting from solar wind plasma and solar radiation, has been extensively studied. However, the influence of the asteroid's rotation on surface charging is not yet fully understood. In this study, a neural network is established to replace numerical integration, improving the efficiency of dynamic 3D simulations. We simulate rotating asteroids and their surrounding plasma environments under various conditions, including the quiet solar wind and solar storms. Different minerals on the asteroid surface are also considered. Additionally, the effects of orbital motion and obliquity are studied for asteroids with rotation periods comparable to their orbital periods. The results show that under the typical solar wind, the maximum and minimum potentials of asteroids gradually decrease with increasing rotation periods, especially when the solar wind is obliquely incident. For asteroids with rotation periods longer than one week, this decreasing trend becomes extremely slow. During a solar storm, the solar wind plasma changes sharply, and the susceptibility of an asteroid's surface potential to rotation is greatly pronounced. Surface minerals also play a role; plagioclase is the most sensitive mineral among those explored, while ilmenite appears indifferent to changes in rotation periods. Understanding the surface charging of asteroids under various rotation periods and angles is crucial for further research on solar wind plasma and asteroids' surface dust motion, providing a reference for the safe landing and exploration of asteroids.

Keywords: Neural networks, Solar wind, Asteroid rotation, Asteroid surfaces
Intergalactic Medium Rotation Measure of Primordial Magnetic Fields. The Faraday rotation effect, quantified by the rotation measure (RM), is a powerful probe of the large-scale magnetization of the Universe—tracing magnetic fields not only on galaxy and galaxy cluster scales but also in the intergalactic medium (IGM; referred to as RMIGM). The redshift dependence of the latter has extensively been explored with observations. It has also been shown that this relation can help to distinguish between different large-scale magnetization scenarios. We study the evolution of this RMIGM for different primordial magnetogenesis scenarios to search for the imprints of primordial magnetic fields (PMFs; magnetic fields originating in the early Universe) on the redshift-dependence of RMIGM. We use cosmological magnetohydrodynamic simulations for evolving PMFs during large-scale structure formation, coupled with the light-cone analysis to produce a realistic statistical sample of mock RMIGM images. We study the predicted behavior for the cosmic evolution of RMIGM for different correlation lengths of PMFs, and provide fitting functions for their dependence on redshifts. We compare these mock RM trends with the recent analysis of the the LOw-Frequency ARray RM Grid and find that large-scale-correlated PMFs should have (comoving) strengths ≲0.75 nG, if they originated during inflation with the scale-invariant spectrum and (comoving) correlation length of ∼19 h ‑1 cMpc or ≲30 nG if they originated during phase-transition epochs with the comoving correlation length of ∼1 h ‑1 cMpc. Our findings agree with previous observations and confirm the results of semi-analytical studies, showing that upper limits on the PMF strength decrease as their coherence scales increase.

Keywords: Extragalactic magnetic fields, Primordial magnetic fields, Large-scale structure of the universe, Intergalactic medium, Magnetohydrodynamical simulations
A Thorough Search for Short-timescale Periodicity in Four Active Repeating Fast Radio Bursts. Fast radio bursts (FRBs) are bright radio transients with millisecond durations, which typically occur at extragalactic distances. The association of FRB 20200428 with the Galactic magnetar SGR J1935+2154 strongly indicates that they could originate from neutron stars, which naturally leads to the expectation that periodicity connected with the spinning of magnetars should exist in the activities of repeating FRBs. However, previous studies have failed to find any signatures supporting such a conjecture. Here we perform a thorough search for short-timescale periodicity in the four most active repeating sources, i.e., FRBs 20121102A, 20200120E, 20201124A, and 20220912A. Three different methods are employed, including a phase folding algorithm, the H-test, and Lomb–Scargle periodograms. For the three most active repeaters from which more than 1000 bursts have been detected, i.e., FRBs 20121102A, 20201124A, and 20220912A, more in-depth period searches are conducted by considering various burst properties such as the pulse width, peak flux, fluence, and the brightness temperature. No clear periodicity is found in a period range of 0.001–1000 s in all efforts. Implications of such a null result on the theoretical models of FRBs are discussed.

Keywords: Neutron stars, Period search , Radio bursts, Magnetars, Time series analysis, Radio transient sources
Infrared Band Strengths and Other Properties of Three Interstellar Compounds—Amorphous Isocyanic Acid, Formaldehyde, and Formic Acid. Infrared (IR) spectral features of interstellar and solar system ices have been attributed to solid organic and inorganic compounds for over 50 yr, but in many cases the laboratory IR data needed to fully quantify such work have never been published, forcing researchers to rely on assumptions about gas- or liquid-phase measurements to interpret data for ices. Here, we report the first mid-IR intensity measurements for isocyanic acid (HNCO) ices that are free of such assumptions, providing new results for use by both observational and laboratory astrochemists. We also report similar new IR data for both formaldehyde (H2CO) and formic acid (HCOOH), which have been discussed in the astrochemical literature for decades, but again without adequate laboratory data to help quantify observational results. Densities and refractive indices of HNCO, H2CO, and HCOOH as amorphous ices also are reported. Two applications of the new H2CO work are presented, the first vapor-pressure measurements of solid H2CO, along with an enthalpy of sublimation, at 100 to 109 K and a set of IR intensities of H2CO in H2O + H2CO ices. Band strengths, absorption coefficients, and optical constants are calculated for all three compounds. Extensive comparisons are made to older results, which are not recommended for future use.

Keywords: Interstellar molecules, Ice spectroscopy, Laboratory astrophysics, Chemical abundances, Astrochemistry