Sazuna/UAT_keywords huggingface dataset:
Relation between the keV–MeV and TeV Emission of GRB 221009A and Its Implications. Gamma-ray bursts (GRBs) are believed to launch relativistic jets, which generate prompt emission by internal processes, and produce long-lasting afterglows by driving external shocks into the surrounding medium. However, how the jet powers the external shock is poorly known. The unprecedented observations of the keV–MeV emission with Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor and the TeV emission with LHAASO of the brightest-of-all-time GRB 221009A offer a great opportunity to study the prompt-to-afterglow transition and the impact of jet on the early dynamics of external shock. In this Letter, we find that the cumulative light curve of keV–MeV emission could well fit the rising stage of the TeV light curve of GRB 221009A, with a time delay,  4.45‑0.26+0.26  s, of TeV emission. Moreover, both the rapid increase in the initial stage and the excess from about T ref + 260 s to 270 s in the TeV light curve are tracking the light-curve bumps in the prompt keV–MeV emission. The close relation between the keV–MeV and TeV emission reveals the continuous energy injection into the external shock. Assuming an energy injection rate exactly following the keV–MeV flux of GRB 221009A, including the very early precursor, we build a continuous energy injection model where the jet Lorentz factor is derived from the TeV time delay, and the TeV data are well fitted, with the TeV excesses interpreted by inverse-Compton scatterings of the inner-coming prompt emission by the energetic electrons in external shock.

Keywords: Gamma-ray bursts, High energy astrophysics
Objects May Be Closer than They Appear: Significant Host Galaxy Dispersion Measures of Fast Radio Bursts in Zoom-in Simulations. We investigate the contribution of host galaxies to the overall dispersion measures (DMs) for fast radio bursts (FRBs) using the Feedback in Realistic Environments (FIRE-2) cosmological zoom-in simulation suite. We calculate DMs from every star particle in the simulated L* galaxies by ray-tracing through their multiphase interstellar medium, summing the line-of-sight free thermal electron column for all gas elements within ±20 kpc of the galactic midplane. At z = 0, we find average (median) host-galaxy DMs of 74 (43) and 210 (94) pc cm‑3 for older (≳10 Myr) and younger (≲10 Myr) stellar populations, respectively. Inclination raises the median DM measured for older populations (≳10 Myr) in the simulations by a factor of ∼2 but generally does not affect the younger stars deeply embedded in H II regions except in extreme edge-on cases (inclination ≳85°). In kinematically disturbed snapshots (z = 1 in FIRE), the average (median) host-galaxy DMs are higher: 80 (107) and 266 (795) pc cm‑3 for older (≳10 Myr) and younger (≲10 Myr) stellar populations, respectively. FIRE galaxies tend to have higher DM values than cosmological simulations such as IllustrisTNG, with larger tails in their distributions to high DMs. As a result, FRB host galaxies may be closer (lower redshift) than previously inferred. Furthermore, constraining host-galaxy DM distributions may help significantly constrain FRB progenitor models.

Keywords: Galaxy structure, Galaxy evolution, Interstellar medium, Radio transient sources
Protostellar Disk Formation Regimes: Angular Momentum Conservation versus Magnetic Braking. Protostellar disks around young protostars exhibit diverse properties, with their radii ranging from less than ten to several hundred astronomical units. To investigate the mechanisms shaping this disk radius distribution, we compiled a sample of 27 Class 0 and I single protostars with resolved disks and dynamically determined protostellar masses from the literature. Additionally, we derived the radial profile of the rotational-to-gravitational-energy ratio in dense cores from the observed specific angular momentum profiles in the literature. Using these observed protostellar masses and rotational energy profile, we computed theoretical disk radii from the hydrodynamic and nonideal magnetohydrodynamic (MHD) models in Y.-N. Lee et al. ﻿and generated synthetic samples to compare with the observations. In our theoretical model, the disk radii are determined by hydrodynamics when the central protostar+disk mass is low. After the protostars and disks grow and exceed certain masses, the disk radii become regulated by magnetic braking and nonideal MHD effects. The synthetic disk radius distribution from this model matches well with the observations. This result suggests that hydrodynamics and nonideal MHD can be dominant in different mass regimes (or evolutionary stages), depending on the rotational energy and protostar+disk mass. This model naturally explains the rarity of large (&gt;100 au) disks and the presence of very small (&lt;10 au) disks. It also predicts that the majority of protostellar disks have radii of a few tens of astronomical units, as observed.

Keywords: Protostars, Magnetohydrodynamics, Star formation, Circumstellar disks
A Spatial Uniformity Check of Gaia DR3 Photometry and BP/RP Spectra. Gaia DR3 photometry and Blue Photometer (BP) and Red Photometer (RP) spectra have been widely used as reference in photometric calibrations. In this work, we check the spatial uniformity of Gaia DR3 photometry and BP/RP spectra by comparing the BP, RP, and G-band photometry with the synthetic ones from the BP/RP spectra. The discrepancies have a small dispersion of 1.07, 0.55, and 1.02 mmag for the BP, RP, and G bands, respectively. However, the discrepancies exhibit obvious spatial patterns, which are clearly associated with Gaia's scanning law. The patterns observed in the BP and G bands are similar, with discrepancies between photometry and spectra being more pronounced in these bands compared to the RP band. A further independent test with the Dark Energy Survey DR2 photometry reveals that the spatial patterns are more likely attributed to the Gaia DR3 BP/RP spectra, particularly in the BP band. On one hand, our results confirm the high spatial uniformity of Gaia data at the mmag level. On the other hand, our results suggest that the spatial uniformity of Gaia DR3 BP/RP spectra is not as good as that of Gaia DR3 photometry, and could be further improved in the future.

Keywords: Calibration, Photometry, Spectroscopy
Rotation of Polarization Angle in Gamma-Ray Burst Prompt Phase. II. The Influence of the Parameters. In addition to the light curve and energy spectrum, polarization is also important for inferring the physical properties of the gamma-ray burst (GRB). Rotation of the polarization angle (PA) with time will cause depolarization of the time-integrated polarization degree. However, it has rarely been studied before. Here, we use a magnetic reconnection model with a large-scale ordered aligned magnetic field in the emitting region to study the influence of the parameters on the PA rotations in the GRB prompt phase. We find that the half-opening angle of the jet θ  j , the observational angle θ  V , and the bulk Lorentz factor Γ all have significant impacts on the PA rotations. The PA rotations are affected by the product value of θ  j Γ0 (Γ0 is the normalization factor of Γ with  Γ(r)=Γ0(r/r0)s ), but are roughly independent of the concrete values of both θ  j  and Γ0. For the typical parameters, the changes of the PA within T 90 (△PA) would be within (12°, 66°) for slight off-axis observations, where T 90 is the duration of the burst with the accumulated flux density ranging from 5% to 95%. The q range for △PA &gt; 10° becomes smaller with the increase of the product value of θ  j Γ0. The most significant PA rotation with △PA ∼ 90° will happen when θ  j Γ0 &gt; 50 and 1.0 &lt; q ≤ 1.2.

Keywords: Gamma-ray bursts, Magnetic fields
The Carousel Lens: A Well-modeled Strong Lens with Multiple Sources Spectroscopically Confirmed by VLT/MUSE. Over the past few years alone, the lensing community has discovered thousands of strong lens candidates, and spectroscopically confirmed hundreds of them. In this time of abundance, it becomes pragmatic to focus our time and resources on the few extraordinary systems, in order to most efficiently study the Universe. In this paper, we present such a system: DESI-090.9854-35.9683, a cluster-scale lens at z l = 0.49, with seven observed lensed sources around the core, and additional lensed sources further out in the cluster. From the number and the textbook configuration of the lensed images, a tight constraint on the mass potential of the lens is possible. This would allow for detailed analysis on the dark and luminous matter content within galaxy clusters, as well as a probe into dark energy and high-redshift galaxies. We present our spatially resolved kinematic measurements of this system from the Very Large Telescope Multi Unit Spectroscopic Explorer, which confirm five of these source galaxies (in ascending order, at z s = 0.962, 0.962, 1.166, 1.432, and 1.432). With previous Hubble Space Telescope imaging in the F140W and F200LP bands, we also present a simple flux-based lens model consisting of two power-law profiles that, for a cluster lens, well models the five lensed arc families with redshifts. We determine the mass to be M(&lt; θ E) = 4.78 × 1013 M ⊙ for the primary mass potential. From the model, we extrapolate the redshift of one of the two source galaxies not yet spectroscopically confirmed to be at  zs=4.52−0.71+1.03 .

Keywords: Galaxy clusters, Strong gravitational lensing, Galaxy spectroscopy, High-redshift galaxies
Testing the ΛCDM Cosmological Model with Forthcoming Measurements of the Cosmic Microwave Background with SPT-3G. We forecast constraints on cosmological parameters enabled by three surveys conducted with SPT-3G, the third-generation camera on the South Pole Telescope. The surveys cover separate regions of 1500, 2650, and 6000 deg2 to different depths, in total observing 25% of the sky. These regions will be measured to white noise levels of roughly 2.5, 9, and  12μK -armin, respectively, in cosmic microwave background (CMB) temperature units at 150 GHz by the end of 2024. The survey also includes measurements at 95 and 220 GHz, which have noise levels a factor of ∼1.2 and 3.5 times higher than 150 GHz, respectively, with each band having a polarization noise level  ∼2  times higher than the temperature noise. We use a novel approach to obtain the covariance matrices for jointly and optimally estimated gravitational lensing potential band powers and unlensed CMB temperature and polarization band powers. We demonstrate the ability to test the ΛCDM model via the consistency of cosmological parameters constrained independently from SPT-3G and Planck data, and consider the improvement in constraints on ΛCDM extension parameters from a joint analysis of SPT-3G and Planck data. The ΛCDM cosmological parameters are typically constrained with uncertainties up to ∼2 times smaller with SPT-3G data, compared to Planck, with the two data sets measuring significantly different angular scales and polarization levels, providing additional tests of the standard cosmological model.

Keywords: Cosmic microwave background radiation, Cosmological parameters
Influence of Black Hole Kick Velocity on Microlensing Distributions. The natal kick velocity distribution for black holes (BHs) is unknown regardless of its importance for understanding the BH formation process. Gravitational microlensing is a unique tool for studying the distribution of BHs in our Galaxy, and the first isolated stellar-mass BH event, OGLE-2011-BLG-0462/MOA-2011-BLG-191 (OB110462), was recently identified by astrometric microlensing. This study investigates how the natal kick velocity for Galactic BHs affects the microlensing event rate distribution. We consider a Maxwell distribution with various average kick velocities, as well as the consequent variation of the spatial distribution of BHs. We find that the event rate for the BH lenses toward the Galactic bulge decreases as v avg increases, mainly due to the scale height inflation. We focus on the unique microlensing parameters measured for OB110462, with microlens parallax π E larger than 0.06 for its long timescale of t E &gt; 200 days. We calculate the expected number of BH events occurring with parameters similar to OB110462 during the OGLE-IV survey by Mróz et al. and compare it with the actual number that occurred, at least one. Our fiducial model predicts 0.52, 0.38, 0.18, 0.042, and 4.0 × 10‑3 events occurring for v avg = 25, 50, 100, 200, and 400 km s‑1, respectively, which suggests that the average kick velocity is likely to be v avg ≲ 100 km s‑1. The expected number smaller than unity even at maximum might indicate our luck in finding OB110462, which can be tested with future surveys by, e.g., the Roman Space Telescope.

Keywords: Gravitational microlensing, Stellar mass black holes
Kappa-tail Technique: Modeling and Application to Solar Energetic Particles Observed by Parker Solar Probe. We develop the kappa-tail fitting technique, which analyzes observations of power-law tails of distributions and energy flux spectra, and connects them to theoretical modeling of kappa distributions, to determine the thermodynamics of the examined space plasma. In particular, we (i) construct the associated mathematical formulation; (ii) prove its decisive lead for determining whether the observed power-law is associated with kappa distributions; and (iii) provide a validation of the technique using pseudo-observations of typical input plasma parameters. Then, we apply this technique to a case study by determining the thermodynamics of solar energetic particle (SEP) protons, for an SEP event observed on 2021 April 17, by the Parker Solar Probe (PSP)/Integrated Science Investigation of the Sun instrument suite on board PSP. The results show SEP temperatures and densities of the order of ∼1 MeV and ∼5 × 10−7 cm−3, respectively.

Keywords: Solar energetic particles, Space plasmas, Solar wind, Heliosphere
UVIT Survey of the Host Galaxies of Active Galactic Nuclei. I. Star Formation Scenarios. Circumnuclear star formation (SF) is generally seen in galaxies hosting active galactic nuclei (AGN); however, the connection between the AGN activity and SF in them is less well understood. To explore this connection on scales of a few tens of parsecs to a few tens of kiloparsecs and larger, we carried out an investigation of SF in seven Seyfert-type AGN and one low-ionization nuclear emission-line region galaxy, using observations with the Ultraviolet Imaging Telescope on board AstroSat in the near-ultraviolet (2000–3000 Å) and far-ultraviolet (1300‑1800 Å) bands. A total of 1742 star-forming regions were identified, having size scales of 0.010–63.642 kpc2. Considering all the galaxies, we found a positive correlation between their total surface density of SF (ΣSFR) and extinction. For five galaxies, namely NGC 1365, NGC 4051, NGC 4321, NGC 5033, and NGC 6814, we found a gradual decrease of both extinction and ΣSFR from the centre to the outer regions. Four sources are found to lie in the main sequence of star-forming galaxies, and the other four lie away from it. We found the ratio of the star formation rate (SFR) in the nuclear region to the total SFR to be positively correlated with the Eddington ratio. This points to the influence of AGN in enhancing the SF characteristics of the hosts. However, the impact is dominant only in the central nuclear region and has no significant effect on the larger scales probed in this work.

Keywords: AGN host galaxies, Ultraviolet astronomy, Seyfert galaxies, Star formation, Galaxy photometry
JWST NIRSpec Spectroscopy of the Triply Lensed z = 10.17 Galaxy MACS0647–JD. We present JWST/NIRSpec prism spectroscopy of MACS0647‑JD, a triply lensed z ∼ 11 candidate discovered in Hubble Space Telescope imaging and spatially resolved by JWST imaging into two components, A and B. Spectroscopy of component A yields a spectroscopic redshift z = 10.17 based on seven detected emission lines: C III] λ λ1907, 1909, [O II] λ3727, [Ne III] λ3869, [Ne III] λ3968, Hδ λ4101, Hγ λ4340, and [O III] λ4363. These are the second-most distant detections of these emission lines to date, in a galaxy observed just 460 million years after the Big Bang. Based on observed and extrapolated line flux ratios we derive a gas-phase metallicity 12 + log(O/H) ∼ 7.5–8.0, or Z ∼ (0.06–0.2) Z ⊙, ionization parameter  log(U)  = ‑1.9 ± 0.2, and an ionizing photon production efficiency  log(ξion)=25.2±0.2  erg‑1 Hz. The spectrum has a softened Lyα break, evidence for a strong Lyα damping wing. The Lyα damping wing also suppresses the F150W photometry, explaining the slightly overestimated photometric redshift z = 10.6 ± 0.3. MACS0647‑JD has a stellar mass log(M/M ⊙) = 8.1 ± 0.3, including ∼6 × 107 M ⊙ in component A, most of which formed recently (within ∼20 Myr) with a star formation rate ∼ 2 ± 1 M ⊙ yr‑1, all within an effective radius 70 ± 24 pc. Spectroscopy of a fainter companion galaxy C separated by a distance of ∼ 3 kpc reveals a Lyman break consistent with z ∼ 10.17. MACS0647‑JD is likely the most distant galaxy merger known.

Keywords: Early universe, Strong gravitational lensing, Reionization, Galaxy spectroscopy, High-redshift galaxies, Galaxies
Multiwavelength Observations for a Double-decker Filament Channel in AR 13102. We present the observational evidence of the existence of a double-decker filament channel (FC) by using observations in extreme ultraviolet and Hα wavelengths. For both FCs, the east foot-point roots in the active region (AR), while the west one roots in the remote quiet region. The bottom FC (FC1) appears as intermittent filaments. Within the AR, the FC1 appears as an S-shaped filament (F1), which consisted of two J-shaped filaments (F1S/F1N for the south/north one). For the upper one (FC2), only the east part is filled with dark plasma and visible as a small filament (F2). Its east foot-point roots around the junction of F1S and F1N. Initially, due to the recurrent reconnections, F1N and F1S link to each other and form a new filament (F3) thread by thread. Meanwhile, the heated plasma, which appears as brightening features, flows from the east foot-point of F2 to the west, and becomes invisible about 1.1 × 105 km away. The failed eruption of F1S is triggered by the reconnection, which appears as the brightening threads changing their configuration from crossed to quasiparallel in between the F1S and F3, and is confined by the upper magnetic field. Associated with the eruption, the distant invisible plasma becomes visible as a brightening feature. It continuously flows to the remote foot-point, and becomes invisible before reaching it. The brightening plasma flow outlines the skeleton of FC2 gradually. The observations show the existence of a double-decker FC, as a magnetic structure, before they appear as a brightening/dark feature when fully filled with hot/cool plasma.

Keywords: Solar activity
Optical Variability Properties of Southern TESS Blazars. We present a study of high-cadence, high-precision optical light curves from the TESS satellite of 67 blazars in the southern sky. We provide descriptive flux statistics, power spectral density (PSD) model parameters, and characteristic variability timescales. We find that only 15 BL Lacertae objects (BLLs) and 18 flat spectrum radio quasars (FSRQs) from the initial 26 and 41, respectively, exhibit statistically significant variability. We employ an adapted power spectral response method to test the goodness of fit for the PSD function to three power-law variant models. From our best-fitting description of the PSD, we extract the high-frequency power-spectral slopes, and if present, determine the significant bend or break in the model to identify characteristic timescales. We find no significant difference in the excess variance or rms scatter between blazar subpopulations. We identify a linear rms–flux relation in ∼69% of our sample, in which ∼20% show a strong correlation. We find that both subpopulations of blazars show power spectral slopes of α ∼ 2 in which a broken power-law best fits five BLLs and six FSRQs and a bending power-law best fits one BLL and five FSRQs. The shortest timescales of variability in each light-curve range widely from minutes to weeks. Additionally, these objects' characteristic timescales range from ∼0.8 to 8 days, consistent with optical variability originating in the jet.

Keywords: BL Lacertae objects, Blazars, Flat-spectrum radio quasars, Active galactic nuclei, Time domain astronomy
Characterizing Solar Center-to-limb Radial-velocity Variability with SDO. Stellar photospheric inhomogeneities are a significant source of noise, which currently precludes the discovery of Earth-mass planets orbiting Sun-like stars with the radial-velocity (RV) method. To complement several previous studies that have used ground- and spaced-based facilities to characterize the RV of the Sun, here we characterize the center-to-limb variability (CLV) of solar RVs arising from various solar-surface inhomogeneities observed by the Solar Dynamics Observatory (SDO)/Helioseismic Magnetic Imager and SDO/Atmospheric Imaging Assembly. By using various SDO observables to classify pixels and calculate line-of-sight velocities as a function of pixel classification and limb angle, we show that each identified feature type, including the umbrae and penumbrae of sunspots, quiet-Sun magnetoconvective cells, magnetic network, and plage, exhibit distinct and complex CLV signatures, including a notable limb-angle dependence in the observed suppression of convective blueshift for magnetically active regions. We discuss the observed distributions of velocities by identified region type and limb angle, offer interpretations of the physical phenomena that shape these distributions, and emphasize the need to understand the RV signatures of these regions as astrophysical signals, rather than simple (un)correlated noise processes.

Keywords: Solar activity, Radial velocity, Sunspots, Stellar activity
A Detailed Analysis of a Magnetic Island Observed by WISPR on Parker Solar Probe. We present the identification and physical analysis of a possible magnetic island feature seen in white-light images observed by the Wide-field Imager for Solar Probe (WISPR) on board the Parker Solar Probe. The island is imaged by WISPR during Parker's second solar encounter on 2019 April 6, when Parker was ∼38 R ⊙ from the Sun's center. We report that the average velocity and acceleration of the feature are approximately 334 km s‑1 and ‑0.64 m s‑2. The kinematics of the island feature, coupled with its direction of propagation, indicate that the island is likely entrained in the slow solar wind. The island is elliptical in shape with a density deficit in its center, suggesting the presence of a magnetic guide field. We argue that this feature is consistent with the formation of this island via reconnection in the current sheet of the streamer. The feature's aspect ratio (calculated as the ratio of its minor to major axis) evolves from an elliptical to a more circular shape that approximately doubles during its propagation through WISPR's field of view. The island is not distinct in other white-light observations from the Solar and Heliospheric Observatory and the Solar Terrestrial Relations Observatory coronagraphs, suggesting that this is a comparatively faint heliospheric feature and that viewing perspective and WISPR's enhanced sensitivity are key to observing the magnetic island.

Keywords: Slow solar wind, Solar corona, Solar magnetic reconnection