Sazuna/UAT_keywords huggingface dataset:
Modeling Gamma-Ray Burst Afterglow Observations with an Off-axis Jet Emission. Gamma-ray bursts (GRBs) are fascinating extragalactic objects. They represent a fantastic opportunity to investigate unique properties not exhibited in other sources. Multiwavelength afterglow observations from some short- and long-duration GRBs reveal an atypical long-lasting emission that evolves differently from the canonical afterglow light curves favoring the off-axis emission. We present an analytical synchrotron afterglow scenario and the hydrodynamical evolution of an off-axis top-hat jet decelerated in a stratified surrounding environment. The analytical synchrotron afterglow model is shown during the coasting, deceleration (off- and on-axis emission), and post-jet break decay phases, and the hydrodynamical evolution is computed by numerical simulations showing the time evolution of the Doppler factor, the half-opening angle, the bulk Lorentz factor, and the deceleration radius. We show that numerical simulations are in good agreement with those derived with our analytical approach. We apply the current synchrotron model and successfully describe the delayed nonthermal emission observed in a sample of long and short GRBs with evidence of off-axis emission. Furthermore, we provide constraints on the possible afterglow emission by requiring the multiwavelength upper limits derived for the closest Swift-detected GRBs and promising gravitational-wave events.

Keywords: Gamma-ray bursts, Non-thermal radiation sources, Interstellar medium
JWST Imaging of Earendel, the Extremely Magnified Star at Redshift z = 6.2. The gravitationally lensed star WHL 0137-LS, nicknamed Earendel, was identified with a photometric redshift z phot = 6.2 ± 0.1 based on images taken with the Hubble Space Telescope. Here we present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8-5.0 μm. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to μ &gt; 4000 and restricting the source plane radius further to r &lt; 0.02 pc, or ~4000 au. These new observations strengthen the conclusion that Earendel is best explained by an individual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of T eff ≃ 13,000-16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from $\mathrm{log}(L)=5.8$ to 6.6 L ⊙, which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.

Keywords: Massive stars, Strong gravitational lensing, Gravitational lensing
Direct Determination of the Activation Energy for Diffusion of OH Radicals on Water Ice. Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods, the behaviors of OH radicals on the surface of an interstellar ice analog were monitored at temperatures between 54 and 80 K. The OH number density on the surface of ultraviolet-irradiated compact amorphous solid water gradually decreased at temperatures above 60 K. Analyzing the temperature dependence of OH intensities with the Arrhenius equation, the decrease can be explained by the recombination of two OH radicals, which is rate-limited by thermal diffusion of OH. The activation energy for surface diffusion was experimentally determined for the first time to be 0.14 ± 0.01 eV, which is larger than or equivalent to those assumed in theoretical models. This value implies that the diffusive reaction of OH radicals starts to be activated at approximately 36 K on interstellar ice.

Keywords: Interstellar dust processes, Astrochemistry
The Dark Matter Tidal Stripping History of the Sagittarius Core with N-body Simulations. The infall of the Sagittarius (Sgr) dwarf spheroidal galaxy in the Milky Way halo is an unique opportunity to understand how the different components of a dwarf galaxy could be tidally removed. In this work, we reconstruct the Sgr core morphology and kinematics on the basis of a model that has already successfully reproduced the Sgr stream. Here we use a very high resolution model that almost resolves individual stars in the Sgr core. It reproduces most of the observed morphology and kinematic properties, without specific fine tuning. We also show that the dark matter may have been almost entirely stripped by Milky Way tides after two passages at the pericenter. Finally the model predicts that the Sgr core will be fully disrupted within the next 2 Gyr.

Keywords: Milky Way disk, Sagittarius dwarf spheroidal galaxy
GOALS-JWST: Unveiling Dusty Compact Sources in the Merging Galaxy IIZw096. We have used the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) to obtain the first spatially resolved, mid-infrared images of IIZw096, a merging luminous infrared galaxy (LIRG) at z = 0.036. Previous observations with the Spitzer Space Telescope suggested that the vast majority of the total IR luminosity (L IR) of the system originated from a small region outside of the two merging nuclei. New observations with JWST/MIRI now allow an accurate measurement of the location and luminosity density of the source that is responsible for the bulk of the IR emission. We estimate that 40%-70% of the IR bolometric luminosity, or 3-5 × 1011 L ⊙, arises from a source no larger than 175 pc in radius, suggesting a luminosity density of at least 3-5 × 1012 L ⊙ kpc-2. In addition, we detect 11 other star-forming sources, five of which were previously unknown. The MIRI F1500W/F560W colors of most of these sources, including the source responsible for the bulk of the far-IR emission, are much redder than the nuclei of local LIRGs. These observations reveal the power of JWST to disentangle the complex regions at the hearts of merging, dusty galaxies.

Keywords: Infrared astronomy, Galaxy mergers, Infrared sources, Luminous infrared galaxies
First Results from the JWST Early Release Science Program Q3D: Turbulent Times in the Life of a z   3 Extremely Red Quasar Revealed by NIRSpec IFU. Extremely red quasars, with bolometric luminosities exceeding 1047 erg s-1, are a fascinating high-redshift population that is absent in the local universe. They are the best candidates for supermassive black holes accreting at rates at or above the Eddington limit, and they are associated with the most rapid and powerful outflows of ionized gas known to date. They are also hosted by massive galaxies. Here we present the first integral field unit observations of a high-redshift quasar obtained by the Near Infrared Spectrograph on board the James Webb Space Telescope (JWST), which targeted SDSS J165202.64+172852.3, an extremely red quasar at z = 2.94. The JWST observations reveal extended ionized gas-as traced by [O III] λ5007 Å-in the host galaxy of the quasar, its outflow, and the circumgalactic medium. The complex morphology and kinematics imply that the quasar resides in a very dense environment with several interacting companion galaxies within projected distances of 10-15 kpc. The high density of the environment and the large velocities of the companion galaxies suggest that this system may represent the core of a forming cluster of galaxies. The system is a good candidate for a merger of two or more dark matter halos, each with a mass of a few 1013 M ⊙, and potentially traces one of the densest knots at z ~ 3.

Keywords: Quasars, Protoclusters, Active galaxies, Emission line galaxies, James Webb Space Telescope, Galaxy spectroscopy
GOALS-JWST: Hidden Star Formation and Extended PAH Emission in the Luminous Infrared Galaxy VV 114. James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) images of the luminous infrared (IR) galaxy VV 114 are presented. This redshift ~0.020 merger has a western component (VV 114W) rich in optical star clusters and an eastern component (VV 114E) hosting a luminous mid-IR nucleus hidden at UV and optical wavelengths by dust lanes. With MIRI, the VV 114E nucleus resolves primarily into bright NE and SW cores separated by 630 pc. This nucleus comprises 45% of the 15 μm light of VV 114, with the NE and SW cores having IR luminosities, L IR(8 - 1000 μm) ~ 8 ± 0.8 × 1010 L ⊙ and ~ 5 ± 0.5 × 1010 L ⊙, respectively, and IR densities, ΣIR ≳ 2 ± 0.2 × 1013 L ⊙ kpc-2 and ≳ 7 ± 0.7 × 1012 L ⊙ kpc-2, respectively-in the range of ΣIR for the Orion star-forming core and the nuclei of Arp 220. The NE core, previously speculated to have an active galactic nucleus (AGN), has starburst-like mid-IR colors. In contrast, the VV 114E SW core has AGN-like colors. Approximately 40 star-forming knots with L IR ~ 0.02-5 × 1010 L ⊙ are identified, 28% of which have no optical counterpart. Finally, diffuse emission accounts for 40%-60% of the mid-IR emission. Mostly notably, filamentary polycyclic aromatic hydrocarbon (PAH) emission stochastically excited by UV and optical photons accounts for half of the 7.7 μm light of VV 114. This study illustrates the ability of JWST to detect obscured compact activity and distributed PAH emission in the most extreme starburst galaxies in the local universe.

Keywords: Star forming regions, Active galaxies, Luminous infrared galaxies, Galaxy nuclei
Monochromatic Globular Clusters as a Critical Test of Formation Models for the Dark Matter-deficient Galaxies NGC 1052-DF2 and NGC 1052-DF4. It was recently proposed that the dark matter-deficient ultradiffuse galaxies DF2 and DF4 in the NGC 1052 group could be the products of a "bullet dwarf" collision between two gas-rich progenitor galaxies. In this model, DF2 and DF4 formed at the same time in the immediate aftermath of the collision, and a strong prediction is that their globular clusters should have nearly identical stellar populations. Here we test this prediction by measuring accurate V 606 - I 814 colors from deep HST/ACS imaging. We find that the clusters are extremely homogeneous. The mean color difference between the globular clusters in DF2 and DF4 is ΔDF2-DF4 = -0.003 ± 0.005 mag, and the observed scatter for the combined sample of 18 clusters with M 606 &lt; -8.6 in both galaxies is σ obs = 0.015 ± 0.002 mag. After accounting for observational uncertainties and stochastic cluster-to-cluster variation in the number of red giants, the remaining scatter is ${\sigma }_{\mathrm{intr}}={0.008}_{-0.006}^{+0.005}$ mag. Both the color difference and the scatter are an order of magnitude smaller than in other dwarf galaxies, and we infer that the bullet scenario passes an important test that could have falsified it. No other formation models have predicted this extreme uniformity of the globular clusters in the two galaxies. We find that the galaxies themselves are slightly redder than the clusters, consistent with a previously measured metallicity difference. Numerical simulations have shown that such differences are expected in the bullet scenario, as the galaxies continued to self-enrich after the formation of the globular clusters.

Keywords: Globular star clusters, Dwarf galaxies, Dark matter
The HI Mass Function of Star-forming Galaxies at z 0.35. The neutral atomic hydrogen (HI) mass function (HIMF) describes the distribution of the HI content of galaxies at any epoch; its evolution provides an important probe of models of galaxy formation and evolution. Here, we report Giant Metrewave Radio Telescope HI 21 cm spectroscopy of blue star-forming galaxies at z ≈ 0.20-0.42 in the Extended Groth Strip, which has allowed us to determine the scaling relation between the average HI mass (M HI ) and the absolute B-band magnitude (M  B ) of such galaxies at z ≈ 0.35, by stacking the HI 21 cm emission signals of galaxy subsamples in different M  B  ranges. We combine this M HI  - M  B  scaling relation (with a scatter assumed to be equal to that in the local universe) with the known B-band luminosity function of star-forming galaxies at these redshifts to determine the HIMF at z ≈ 0.35. We show that the use of the correct scatter in the M HI  - M  B  scaling relation is critical for an accurate estimate of the HIMF. We find that the HIMF has evolved significantly from z ≈ 0.35 to z ≈ 0, i.e., over the last 4 Gyr, especially at the high-mass end. High-mass galaxies, with M HI  ≳ 1010 M ⊙, are a factor of ≈3.4 less prevalent at z ≈ 0.35 than at z ≈ 0. Conversely, there are more low-mass galaxies, with M HI  ≈ 109 M ⊙, at z ≈ 0.35 than in the local universe. While our results may be affected by cosmic variance, we find that massive star-forming galaxies have acquired a significant amount of HI through merger events or accretion from the circumgalactic medium over the past 4 Gyr.

Keywords: Radio spectroscopy, High-redshift galaxies, Galaxy evolution, H I line emission
Laboratory and Astronomical Detection of the SiP Radical (X<SUP>2</SUP>Π<SUB> i </SUB>): More Circumstellar Phosphorus. The millimeter-wave spectrum of the SiP radical (X2Πi) has been measured in the laboratory for the first time using direct-absorption methods. SiP was created by the reaction of phosphorus vapor and SiH4 in argon in an AC discharge. Fifteen rotational transitions (J + 1 ← J) were measured for SiP in the Ω = 3/2 ladder in the frequency range 151-533 GHz, and rotational, lambda doubling, and phosphorus hyperfine constants determined. Based on the laboratory measurements, SiP was detected in the circumstellar shell of IRC+10216, using the Submillimeter Telescope and the 12 m antenna of the Arizona Radio Observatory at 1 mm and 2 mm, respectively. Eight transitions of SiP were searched: four were completely obscured by stronger features, two were uncontaminated (J = 13.5 → 12.5 and 16.5 → 15.5), and two were partially blended with other lines (J = 8.5 → 7.5 and 17.5 → 16.5). The SiP line profiles were broader than expected for IRC+10216, consistent with the hyperfine splitting. From non-LTE radiative transfer modeling, SiP was found to have a shell distribution with a radius ~300 R *, and an abundance, relative to H2, of f ~ 2 × 10-9. From additional modeling, abundances of 7 × 10-9 and 9 × 10-10 were determined for CP and PN, respectively, both located in shells at 550-650 R *. SiP may be formed from grain destruction, which liberates both phosphorus and silicon into the gas phase, and then is channeled into other P-bearing molecules such as PN and CP.

Keywords: Interstellar molecules, Circumstellar envelopes, Evolved stars, Molecular spectroscopy, Chemical abundances, Astrochemistry, Asymptotic giant branch stars
Spectroscopic and Imaging Observations of Spatially Extended Magnetic Reconnection in the Splitting of a Solar Filament Structure. On the Sun, Doppler shifts of bidirectional outflows from the magnetic-reconnection site have been found only in confined regions through spectroscopic observations. Without spatially resolved spectroscopic observations across an extended region, the distribution of reconnection and its outflows in the solar atmosphere cannot be made clear. Magnetic reconnection is thought to cause the splitting of filament structures, but unambiguous evidence has been elusive. Here we report spectroscopic and imaging analysis of a magnetic-reconnection event on the Sun, using high-resolution data from the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. Our findings reveal that the reconnection region extends to an unprecedented length of no less than 14,000 km. The reconnection splits a filament structure into two branches, and the upper branch erupts eventually. Doppler shifts indicate clear bidirectional outflows of ~100 km s-1, which decelerate beyond the reconnection site. Differential-emission-measure analysis reveals that in the reconnection region the temperature reaches over 10 MK and the thermal energy is much larger than the kinetic energy. This Letter provides definite spectroscopic evidence for the splitting of a solar filament by magnetic reconnection in an extended region.

Keywords: Solar filaments, Solar magnetic reconnection, Solar filament eruptions
Reconciling Parker Solar Probe Observations and Magnetohydrodynamic Theory. The Parker Solar Probe mission provides a unique opportunity to characterize several features of the solar wind at different heliocentric distances. Recent findings have shown a transition in the inertial range spectral and scaling properties around 0.4-0.5 au when moving away from the Sun. Here we provide, for the first time, how to reconcile these observational results on the radial evolution of the magnetic and velocity field fluctuations with two scenarios drawn from the magnetohydrodynamic theory. The observed breakdown is the result of the radial evolution of magnetic field fluctuations and plasma thermal expansion affecting the distribution between magnetic and velocity fluctuations. The two scenarios point toward an evolving nature of the coupling between fields that can be also reconciled with Kraichnan and Kolmogorov pictures of turbulence. Our findings have important implications for turbulence studies and modeling approaches.

Keywords: Interplanetary turbulence, Magnetohydrodynamics, Solar wind, Interplanetary magnetic fields
Two Remarkably Luminous Galaxy Candidates at z ≈ 10-12 Revealed by JWST. The first few 100 Myr at z &gt; 10 mark the last major uncharted epoch in the history of the universe, where only a single galaxy (GN-z11 at z ≈ 11) is currently spectroscopically confirmed. Here we present a search for luminous z &gt; 10 galaxies with JWST/NIRCam photometry spanning ≈1-5 μm and covering 49 arcmin2 from the public JWST Early Release Science programs (CEERS and GLASS). Our most secure candidates are two M UV ≈ -21 systems: GLASS-z12 and GLASS-z10. These galaxies display abrupt ≳1.8 mag breaks in their spectral energy distributions (SEDs), consistent with complete absorption of flux bluewards of Lyα that is redshifted to $z={12.4}_{-0.3}^{+0.1}$ and $z={10.4}_{-0.5}^{+0.4}$ . Lower redshift interlopers such as quiescent galaxies with strong Balmer breaks would be comfortably detected at &gt;5σ in multiple bands where instead we find no flux. From SED modeling we infer that these galaxies have already built up ~109 solar masses in stars over the ≲300-400 Myr after the Big Bang. The brightness of these sources enable morphological constraints. Tantalizingly, GLASS-z10 shows a clearly extended exponential light profile, potentially consistent with a disk galaxy of r 50 ≈ 0.7 kpc. These sources, if confirmed, join GN-z11 in defying number density forecasts for luminous galaxies based on Schechter UV luminosity functions, which require a survey area &gt;10× larger than we have studied here to find such luminous sources at such high redshifts. They extend evidence from lower redshifts for little or no evolution in the bright end of the UV luminosity function into the cosmic dawn epoch, with implications for just how early these galaxies began forming. This, in turn, suggests that future deep JWST observations may identify relatively bright galaxies to much earlier epochs than might have been anticipated.

Keywords: Early universe, Galaxy formation, James Webb Space Telescope, Galaxy evolution, High-redshift galaxies
SKYSURF-3: Testing Crowded Object Catalogs in the Hubble eXtreme Deep Field Mosaics to Study Sample Incompleteness from an Extragalactic Background Light Perspective. Extragalactic background light (EBL) studies have revealed a significant discrepancy between direct measurements-via instruments measuring "bare" sky from which Zodiacal and Galactic light models are subtracted-and measurements of the integrated galaxy light (IGL). This discrepancy could lie in either method, whether it be an incomplete Zodiacal model or missed faint galaxies in the IGL calculations. It has been proposed that the discrepancy is due to deep galaxy surveys, such as those with the Hubble Space Telescope, missing up to half of the faint galaxies with 24 ≲ m AB ≲ 29 mag. We address this possibility by simulating higher number densities of galaxies, and so assess incompleteness due to object overlap, with three replications of the Hubble UltraDeep Field (HUDF). SourceExtractor is used to compare the recovered counts and photometry to the original HUDF, allowing us to assess how many galaxies may have been missed due to confusion, i.e., due to blending with neighboring faint galaxies. This exercise reveals that, while up to 50% of faint galaxies with 28 ≲ m AB ≲ 29 mag were missed or blended with neighboring objects in certain filters, not enough were missed to account for the EBL discrepancy alone in any of the replications.

Keywords: Extragalactic astronomy, Hubble Space Telescope, Zodiacal cloud, Galaxy counts
The Halo Bias inside Cosmic Voids. The bias of dark matter halos and galaxies is a crucial quantity in many cosmological analyses. In this work, using large cosmological simulations, we explore the halo mass function and halo bias within cosmic voids. For the first time to date, we show that they are scale dependent along the void profile, and provide a predictive theoretical model of both the halo mass function and halo bias inside voids, recovering for the latter a 1% accuracy against simulated data. These findings may help shed light on the dynamics of halo formation within voids and improve the analysis of several void statistics from ongoing and upcoming galaxy surveys.

Keywords: Cosmology, Galaxy dark matter halos, Voids, Large-scale structure of the universe
A First Look at Cepheids in a Type Ia Supernova Host with JWST. We report the first look at extragalactic Cepheid variables with the James Webb Space Telescope (JWST), obtained from an archival observation of NGC 1365, host of SNIa 2012fr, a calibration path used to measure the Hubble constant. As expected, the high-resolution observations with NIRCam through F200W show better source separation from line-of-sight companions than Hubble Space Telescope (HST) images at similar near-infrared wavelengths, the spectral region that has been used to mitigate the impact of host dust on distance measurements. Using the standard star P330E as a zero-point and point-spread function reference, we photometered 31 previously known Cepheids in the JWST field, spanning $1.15\lt \mathrm{log}P\lt 1.75$ including 24 Cepheids in the longer-period interval of $1.35\lt \mathrm{log}P\lt 1.75$ . We compared the resultant period-luminosity (P-L) relations to that of 49 Cepheids in the full period range including 38 in the longer-period range observed with WFC3/IR on HST and transformed to the JWST photometric system (F200W, Vega). The P-L relations measured are in good agreement, with intercepts (at $\mathrm{log}P=1$ ) of 25.74 ± 0.04 and 25.72 ± 0.05 for HST and JWST, respectively. Our baseline result comes from the longer-period, higher signal-to-noise ratio Cepheids where we find 25.75 ± 0.05 and 25.75 ± 0.06 mag for HST and JWST, respectively. We find good consistency between this first JWST measurement and HST, and no evidence that HST Cepheid photometry is "biased bright" at the ~0.2 mag level needed to mitigate the Hubble tension, though comparisons from more SN hosts are warranted and anticipated. We expect future optimized JWST observations to surpass these in quality.

Keywords: Hubble constant, James Webb Space Telescope, Cepheid distance, Cepheid variable stars