Sazuna/UAT_keywords huggingface dataset:
Probing Evolution of Long Gamma-Ray Burst Properties through Their Cosmic Formation History. The astrophysics of long gamma-ray burst (LGRB) progenitors as well as possible cosmological evolution in their properties still poses many open questions. Previous studies suggest that the LGRB rate density (LGRB-RD) follows the cosmic star formation rate density (SFRD) only at high-z and attribute this to the metallicity evolution of progenitor stars. For low z, opinions differ on whether the uptick in the LGRB-RD is due to a distinct class of low-luminosity GRBs or perhaps even a different progenitor subclass. To investigate these questions, we utilize data from the Neil Gehrels Swift Observatory and ground-based observatories (redshift). To test the hypothesis that the observations can be mapped (with/without evolution) to the well-established cosmic SFRD, we consider three cases: no evolution, beaming angle evolution, and a simple power-law evolution. The comparison shows that the "no evolution" case can be ruled out. Our study highlights that the beaming angle evolution or the simple power-law evolution is also not sufficient to obtain a good match between the LGRB-RD and SFRD. Rather, the inclusion of multiple evolving properties of LGRBs in combination appears to be required to match the two rate densities in their entirety.

Keywords: Cosmology, Gamma-ray bursts, Star formation
Cluster Lensing Mass Inversion (CLUMI+): Combining Dynamics and Weak Lensing around Galaxy Clusters. We present CLUMI+, a self-consistent, multiprobe methodology for reconstructing the mass distribution in and around galaxy clusters by combining gravitational lensing and dynamical observations. Building on the joint likelihood framework of K. Umetsu, CLUMI+ integrates weak-lensing shear and magnification data with projected escape velocity measurements in the cluster infall region, yielding tighter constraints on the gravitational potential without relying on equilibrium assumptions. The mass distribution is modeled using a flexible, piecewise-defined convergence profile that characterizes the azimuthally averaged surface mass density within the lensing field, transitioning to a projected power-law form at larger radii where phase-space constraints complement lensing. Additional strong-lensing constraints are incorporated via central aperture-mass measurements, enabling full-scale mass reconstruction from the cluster core to the outskirts. We validate CLUMI+ using synthetic weak-lensing and phase-space data for a massive cluster from the IllustrisTNG simulations, demonstrating unbiased recovery of projected and three-dimensional mass profiles and achieving 10%─30% improvement in precision at large radii. As a case study, we apply CLUMI+ to A2261, combining Subaru and Hubble Space Telescope weak+strong-lensing data with spectroscopic measurements from the Hectospec Cluster Survey. This analysis demonstrates the power of multiprobe, equilibrium-free modeling for robust cluster mass reconstruction.

Keywords: Galaxy clusters, Weak gravitational lensing, Dark matter distribution, Large-scale structure of the universe, Gravitational fields, Strong gravitational lensing, Redshift surveys
The Structure of the Giant Radio Fossil in the Ophiuchus Galaxy Cluster. We present high-sensitivity follow-up observations of the giant fossil radio lobe in the Ophiuchus galaxy cluster with the upgraded Giant Metrewave Radio Telescope in the 125─250 and 300─500 MHz frequency bands. The new data have sufficient angular resolution to exclude compact sources and enable us to trace the faint extended emission from the relic lobe to a remarkable distance of 820 kpc from the cluster center. The new images reveal intricate spatial structure within the fossil lobe, including narrow (5─10 kpc), long (70─100 kpc) radio filaments embedded within the diffuse emission at the bottom of the lobe. The filaments exhibit a very steep spectrum (Sν ∝ ν−α with α ∼ 3), significantly steeper than the ambient synchrotron emission from the lobe (α ∼ 1.5─2); they mostly disappear in recently published MeerKAT images at 1.28 GHz. Their origin is unclear; similar features observed in some other radio lobes typically have a spectrum flatter than that of their ambient medium. These radio filaments may trace regions where the magnetic field has been stretched and amplified by gas circulation within the rising bubble. The spectrum of the brightest region of the radio lobe exhibits a spectral break, which corresponds to a radiative cooling age of the fossil lobe of approximately 174 Myr, giving a date for this most powerful active galactic nucleus explosion.

Keywords: Galaxy clusters, Extragalactic radio sources, Radio galaxies, Intracluster medium, Radio astronomy
FEAST: Probing the Stellar Population of the Starburst Dwarf Galaxy NGC 4449 with JWST/NIRCam. We present new JWST/NIRCam observations of the starburst irregular galaxy NGC 4449, obtained in Cycle 1 as part of the Feedback in Emerging extrAgalactic Star clusTers program, which we use to investigate its resolved stellar populations and their spatial distributions. NGC 4449 near-IR color–magnitude diagrams reveal a broad range of stellar populations, spanning different evolutionary phases, from young main sequence stars, to old red giant branch stars and asymptotic giant branch (AGB) stars. The analysis of their spatial distributions shows that younger (≤10 Myr) populations form an S-shaped distribution aligned with the galaxy's north–south axis, while stars aged 10–60 Myr show shifting concentrations from the north to the south, consistent with the possibility that external interactions or tidal effects may have triggered star formation in spatially distinct bursts. Clusters of comparable ages generally follow these distributions, suggesting that cluster and field stars form at the same pace in each galaxy region. Thanks to the unprecedented high-spatial resolution and sensitivity of the JWST data, we recover a clear gap between oxygen-rich and the carbon star branch of the AGB population, as well as the presence of a massive AGB star "finger." The analysis of these stars can provide constraints on AGB evolution models and dust production in this galaxy. These results confirm NGC 4449's status as a compelling example of a local dwarf starburst galaxy undergoing complex and possibly externally driven star formation and underscore the power of JWST in probing the full lifecycle of stars in nearby starburst systems.

Keywords: Starburst galaxies, Magellanic irregular galaxies
Parker Solar Probe Observations of Turbulence and Waves between a Current Sheet and an Interplanetary Coronal Mass Ejection–Driven Shock. We report on unusual magnetic wave activity seen in a region between the crossing of a current sheet and an interplanetary shock by the Parker Solar Probe (PSP). The PSP observed a shock driven by an interplanetary coronal mass ejection on 2021 June 30 at 14:58:19 at 0.76 au. Prior to the arrival of the shock, PSP encountered a current sheet on 2021 June 30 at 14:54:54. Through an analysis of the magnetic field and plasma measurements, we determine that the shock is a fast forward quasi-parallel shock. The magnetic field in the region between the current sheet and the shock was characterized by enhanced magnetic wave activity. To investigate the plasma waves in the region, a wavelet technique is applied to obtain the magnetic field fluctuation power spectral density, normalized reduced helicity, and magnetic field fluctuation hodogram. The results of the analysis reveal that the waves present in this region demonstrate right-hand polarization and have a relatively broad range of frequencies in the spacecraft frame. Our analyses reveal the simultaneous presence of low-frequency magnetohydrodynamic waves and whistler waves within this region and note that these waves become active precisely at the time of the current sheet crossing. The coexistence of different types of waves within this region presents a unique opportunity for further investigation and deepening our understanding of the underlying physical mechanisms governing these phenomena.

Keywords: Interplanetary turbulence, Solar wind, Interplanetary shocks
Dynamical Instability of Multiplanet Systems and Free-floating Planets. The ejection of planets by the instability of planetary systems is a potential source of free-floating planets. We numerically simulate multiplanet systems to study the evolution process, the properties of the surviving systems, and the statistics of the ejected planets. For systems with only super-Earth planets, we find that the time (in units of the orbital period P1 of the innermost planet) for the system to lose the first planet by collision or ejection increases with the semimajor axis of the innermost planet. In contrast, the time (in units of P1) for the first close encounter between two planets is identical. These two timescales also depend differently on the orbital spacing between the planets. Most systems with only super-Earths do not have planets ejected. In systems with super-Earths and a cold Jupiter, we discover that a cold Jupiter significantly increases the probability of ejection of the super-Earths by close encounters. For 38% of the ejected super-Earths, most velocities relative to their parent stars are smaller than 6 km s‑1. We conservatively estimate that more than 86% of the surviving two-planet systems in the super-Earths-plus-cold-Jupiter sample are long-term stable by using empirical criteria. Most super-Earths in the remaining two-planet systems are on highly elliptical but stable orbits and have migrated inward compared with their initial states.

Keywords: Exoplanet dynamics, Planetary system evolution, Celestial mechanics, Free floating planets, Planetary dynamics
Cosmic-Ray Feedback from Supernovae in a Parker-unstable Medium. Supernova energy drives interstellar medium (ISM) turbulence and can help launch galactic winds. What difference does it make if 10% of the energy is initially deposited into cosmic rays? To help answer this question and study cosmic-ray feedback, we perform galactic patch simulations of a stratified ISM in a low star formation rate, high magnetic field regime. We compare two magnetohydrodynamic and cosmic-ray simulations, which are identical except for how each supernova's energy is injected. In one, 10% of the energy is injected as cosmic-ray energy. In the other case, energy injection is strictly thermal and kinetic. We find that cosmic-ray injections drive a faster, hotter, and more massive outflow long after the injections occur. Both simulations show the formation of cold clouds (with a total mass fraction &gt; 50%) through the Parker instability and thermal instability. The Parker instability simultaneously produces high mass loading factors η &gt; 103 as it does not directly require star formation and supernovae. We also show how the Parker instability naturally leads to a decorrelation of cosmic-ray pressure and gas density. This decorrelation leads to a significant decrease in the calorimetric fraction for injected cosmic rays, but it depends on having a highly resolved magnetic field.

Keywords: Cosmic rays, Stellar feedback, Interstellar medium, Magnetohydrodynamical simulations
Characterizing 3D Magnetic Fields and Turbulence in H I Clouds. 3D Galactic magnetic fields are critical for understanding the interstellar medium, Galactic foreground polarization, and the propagation of ultra-high-energy cosmic rays. Leveraging recent theoretical insights into anisotropic magnetohydrodynamic (MHD) turbulence, we introduce a deep learning framework to predict the full 3D magnetic field structure, including the plane-of-sky (POS) position angle, line-of-sight (LOS) inclination, magnetic field strength, sonic Mach number (Ms), and Alfvén Mach number (MA), from spectroscopic H I observations. The deep learning model is trained on synthetic H I emission data generated from multiphase 3D MHD simulations. We then apply the trained model to observational data from the Commensal Radio Astronomy FAST Survey, presenting maps of 3D magnetic field orientation, magnetic field strength, Ms, and MA for two H I clouds—a low-velocity cloud and an intermediate-velocity cloud, which overlap in the POS yet reside at different LOS distances. The deep-learning-predicted POS magnetic field position angles align closely with those determined using the velocity gradient technique, whose integrated results are consistent with independent measurements from Planck 353 GHz polarization data. This study demonstrates the potential of deep learning approaches as powerful tools for modeling the 3D distributions of 3D Galactic magnetic fields and turbulence properties throughout the Galaxy.

Keywords: Interstellar magnetic fields, Neutral hydrogen clouds, Interstellar medium, Magnetohydrodynamical simulations
High-resolution Observation of Minifilament Eruptions near a Coronal Hole Boundary and Their Response in the Solar Corona. We investigated minifilament (MF) eruptions (MFEs) near coronal hole (CH) boundaries to explore their role in coronal dynamics and their potential contributions to the solar wind. Using high-resolution Hα images from the 1.6 m Goode Solar Telescope at Big Bear Solar Observatory and Atmospheric Imaging Assembly 193 Å extreme ultraviolet (EUV) data from Solar Dynamics Observatory, we analyzed 28 MFE events over 7.5 hr of observation spanning 5 days. The three largest MF eruptions triggered distinct coronal responses: two consecutive MFEs produced a small-scale eruptive coronal ejection, while the other generated a jetlike brightening. Furthermore, the 25 smaller-scale MFEs were associated with localized brightenings in coronal bright points. These findings suggest that MFs play a significant role in transferring mass and magnetic flux to the corona, particularly within CH regions. We found a certain trend that the size of MFEs is correlated with the EUV emissions. In addition, we observed magnetic flux cancellation associated with MFEs. However, except for a few of the largest MFEs, quantitative analysis of magnetic field evolution is beyond the capability of the data. These results underscore the importance of MFEs in the dynamic coupling between the chromosphere and corona, highlighting their potential role in shaping heliospheric structures.

Keywords: Solar coronal holes, Quiet sun, Solar chromosphere, Solar filament eruptions
Cosmogenic Neutrino Point Source and KM3-230213A. Cosmogenic neutrinos (CNs) are produced by ultra-high-energy cosmic rays (UHECRs) interacting with cosmic background radiation. We investigated the properties of CN point/extended sources, i.e., the neutrino spectrum and angular profile as functions of time, by assuming that UHECR sources are transient events, such as gamma-ray bursts. The properties depend much on the intergalactic magnetic field (IGMF), but the angular extent is in general subdegree, within which the CN flux can overshoot the diffuse CN flux in early time. The nearby CN point sources could be detected for the low IGMF case by future neutrino telescopes. The recent KM3-230213A event is possible to account for by a nearby transient CN source, rather than diffuse CN emission. Observations of CN point sources will provide a chance to search for UHECR sources.

Keywords: Gamma-ray bursts, High energy astrophysics, Ultra-high-energy cosmic radiation, Neutrino astronomy, Cosmic ray sources, Particle astrophysics
Intra-night Optical Variability and Radio Characteristics of Extremely Radio-loud Narrow-line Seyfert 1 Galaxies. Narrow-line Seyfert 1 galaxies (NLS1s) are generally known to be radio-quiet active galactic nuclei, but a tiny subset of them are found to be extremely radio-loud with radio loudness parameter (R1.4 GHz) &gt; 100. Given their rarity, we investigated intra-night optical variability (INOV) and radio characteristics of a sample of 16 extremely radio-loud NLS1s. For all but four sample sources we report intra-night photometric monitoring for the first time with at least one monitoring session per source lasting for a minimum of 3.0 hr duration. In our sample, we detect INOV with a high duty cycle (up to 25%) and large average amplitude ( ψ¯ ∼ 0.16) similar to that found in blazars. Using 3.0 GHz Very Large Array Sky Survey and auxiliary multifrequency radio data we find that our RL-NLS1s are luminous (L3.0 GHz ≥ 1024 W Hz‑1), compact (less than a few kpc), variable, flat spectrum (αradio&gt; ‑0.5) radio sources. The INOV, radio characteristics, and radio luminosity (L1.4 GHz) versus supermassive black hole mass (MSMBH) plot infer that extremely radio-loud NLS1s are low-z and low-luminosity analogs of flat spectrum radio quasars wherein the former are powered by, on average, one order-of-magnitude less massive SMBHs.

Keywords: Supermassive black holes, Optical observation, Blazars, Flat-spectrum radio quasars, Seyfert galaxies, Active galactic nuclei
Key Physical Parameters Influencing Fragmentation and Multiplicity in Dense Cores of Orion A. When dense cores in molecular clouds or filamentary structures collapse and form protostars, they may undergo fragmentation and form binary or multiple systems. In this paper, we investigate the key mechanisms influencing fragmentation, by comparing the physical conditions of fragmented and unfragmented dense cores (∼0.1 pc) in Orion A. Utilizing archival submillimeter continuum data from the James Clerk Maxwell Telescope (JCMT) and the Atacama Large Millimeter/submillimeter Array survey of Class 0 and I protostars at 0 .″ 1 resolution, we identified 38 dense cores hosting single protostars and 15 cores hosting binary or multiple systems. We measured the dense core properties using Herschel dust temperature, Nobeyama 45 m N2H+ J = 1−0, and JCMT polarization data. Our results reveal that the dense cores hosting binary/multiple systems exhibit significantly higher densities and Mach numbers compared to those hosting single protostars, while there are no correlations between the occurrence of fragmentation and the energy ratios of turbulence and magnetic field to gravity. Our results suggest that the higher density and supersonic turbulence of dense cores can lead to local collapse and fragmentation, to form binary/multiple systems, while the magnetic field has limited influence on fragmentation in the dense cores in Orion A.

Keywords: Multiple stars, Star forming regions, Interstellar magnetic fields, Star formation, Low mass stars, Protostars
The Physical Origin and Time Lag of Multifrequency Flares from Sgr A*. Sagittarius A*, the supermassive black hole at the center of our galaxy, exhibits flares across various wavelengths, yet its origin remains elusive. We performed 3D two-temperature general relativistic magnetohydrodynamic simulations of magnetized accretion flows initialized from multiloop magnetic field configuration onto a rotating black hole and conducted general relativistic radiative transfer (GRRT) calculations considering contributions from both thermal and nonthermal synchrotron emission processes. Our results indicate that the polarity inversion events from the multiloop magnetic field configurations can generate 138 THz flares consistent with observations with the help of nonthermal emission. By tracing the intensity evolution of light rays in GRRT calculations, we identify the precise location of the flaring region and confirm that it originates from a large-scale polarity inversion event. We observe time delays between different frequencies, with lower-frequency radio flares lagging behind higher frequencies due to plasma self-absorption in the disk. The time delay between near-infrared and 43 GHz flares can reach up to ∼50 minutes, during which the flaring region gradually shifts outward, becoming visible at lower frequencies. Our study confirms that large-scale polarity inversion in a standard and normal evolution accretion flow with a multiloop initial magnetic configuration can be a potential mechanism driving flares from Sgr A*.

Keywords: Accretion, Supermassive black holes, Magnetohydrodynamics, Low-luminosity active galactic nuclei, Radiative transfer, Radiative processes, Astrophysical black holes, Magnetohydrodynamical simulations
Unraveling the Variation Mechanism of CTA 102: A Combined Spectral and Polarization Investigation. The variation mechanism of blazars has been a longstanding question. As a target exhibiting extreme variability, CTA 102 offers a unique window into this puzzle. In this study, we collect multiwavelength flux data, optical spectra, and polarization data of CTA 102 spanning approximately 10 yr. We apply the localized cross-correlation function to analyze the correlation between the multiwavelength light curves. Based on the lag analysis, we find that the γ-ray, optical, and X-ray emitting regions are cospatial, all located at  4.6‑1.1+1.1  pc upstream of the radio emitting region. On long timescales, the optical spectral behavior exhibits a transition from the redder-when-brighter trend to the bluer-when-brighter trend. Similarly, the γ-ray spectral behavior turns from the softer-when-brighter trend to the harder-when-brighter trend. The trend transitions could be explained by the two-component model, via the modulation of either the Doppler factor δ or the intrinsic peak frequency  νp' . For the long-term behavior of the polarization degree (PD), we find that the two-component model can also quantitatively explain the correlation between the PD and the optical flux. On short timescales, the clockwise rotation on the q–u plane could be explained by the helical jet model, while the oscillation on the q–u plane may result from variations of the compression coefficient within the shock-in-jet model.

Keywords: Blazars, Flat-spectrum radio quasars, Active galactic nuclei
CANUCS/Technicolor: JWST Medium-band Photometry Finds Half of the Star Formation at z &gt; 7.5 Is Obscured. We present a sample of 110 high-redshift (z &gt; 7.5) galaxies from the CANUCS and Technicolor surveys, showcasing photometry in every wide- and medium-band NIRCam filter in addition to ancillary Hubble Space Telescope data sampling 0.4–5 μm (22 JWST bands out of 29 bands total). Additionally, 47 (43%) galaxies in our sample meet criteria to be classified as extreme emission line galaxies, 17 (15%) of which are completely missed by typical dropout selections due to faint ultraviolet (UV) emission. By fitting the spectral energy distributions covering the rest-frame UV to optical at z &gt; 7.5, we investigate the dust obscuration properties, giving an unbiased view of dust buildup in high-redshift galaxies free from spectroscopic follow-up selection effects. Dust attenuation correlates with stellar mass, but more strongly with star formation rate. We find typical galaxies at z &gt; 7.5 have ∼25% of their star formation obscured. However, since galaxies with higher star formation rates suffer more attenuation, ∼50% of the total star formation rate density at 7.5 &lt; z &lt; 9 is obscured. The obscured fraction drops to ∼25% in our 9 &lt; z &lt; 12 bin, possibly due to substantial dust grain growth in the interstellar medium not having time to occur. Extrapolating the decline in dust obscuration of galaxies to higher redshifts, we infer that dust obscuration should approach zero at z &gt; 15, implying that epoch as when dust first forms in bright galaxies.

Keywords: Interstellar dust, James Webb Space Telescope, High-redshift galaxies, Photometry