Sazuna/UAT_keywords huggingface dataset:
Characterizing Compact 15-33 GHz Radio Continuum Sources in Local U/LIRGs. We present the analysis of ~100 pc scale compact radio continuum sources detected in 63 local (ultra)luminous infrared galaxies (U/LIRGs; L IR ≥ 1011 L ☉), using FWHM ≲ 0.″1-0.″2 resolution 15 and 33 GHz observations with the Karl G. Jansky Very Large Array. We identify a total of 133 compact radio sources with effective radii of 8-170 pc, which are classified into four main categories-"AGN" (active galactic nuclei), "AGN/SBnuc" (AGN-starburst composite nucleus), "SBnuc" (starburst nucleus), and "SF" (star-forming clumps)-based on ancillary data sets and the literature. We find that "AGN" and "AGN/SBnuc" more frequently occur in late-stage mergers and have up to 3 dex higher 33 GHz luminosities and surface densities compared with "SBnuc" and "SF," which may be attributed to extreme nuclear starburst and/or AGN activity in the former. Star formation rates (SFRs) and surface densities (ΣSFR) are measured for "SF" and "SBnuc" using both the total 33 GHz continuum emission (SFR ~ 0.14-13 M ☉ yr-1, ΣSFR ~ 13-1600 M ☉ yr-1 kpc-2) and the thermal free-free emission from H II regions (median SFRth ~ 0.4 M ☉ yr-1, ${{\rm{\Sigma }}}_{{\mathrm{SFR}}_{\mathrm{th}}}\sim 44\,{M}_{\odot }$ yr-1 kpc-2). These values are 1-2 dex higher than those measured for similar-sized clumps in nearby normal (non-U/LIRGs). The latter also have a much flatter median 15-33 GHz spectral index (~-0.08) compared with "SBnuc" and "SF" (~-0.46), which may reflect higher nonthermal contribution from supernovae and/or interstellar medium densities in local U/LIRGs that directly result from and/or lead to their extreme star-forming activities on 100 pc scales.

Keywords: Very Large Array, Star forming regions, Galaxy nuclei, Radio continuum emission, Luminous infrared galaxies
A Radio-selected Population of Dark, Long Gamma-Ray Bursts: Comparison to the Long Gamma-Ray Burst Population and Implications for Host Dust Distributions. We present centimeter-band and millimeter-band afterglow observations of five long-duration γ-ray bursts (GRBs; GRB 130131A, 130420B, 130609A, 131229A, 140713A) with dust-obscured optical afterglow emission, known as "dark" GRBs. We detect the radio afterglow of two of the dark GRBs (GRB 130131A and 140713A), along with a tentative detection of a third (GRB 131229A) with the Karl G. Jansky Very Large Array (VLA). Supplemented by three additional VLA-detected dark GRBs from the literature, we present uniform modeling of their broadband afterglows. We derive high line-of-sight dust extinctions of A  V,GRB ≈ 2.2- ≳ 10.6 mag. Additionally, we model the host galaxies of the six bursts in our sample, and derive host galaxy dust extinctions of A  V,Host ≈ 0.3-4.7 mag. Across all tested γ-ray (fluence and duration) and afterglow properties (energy scales, geometries, and circumburst densities), we find dark GRBs to be representative of more typical unobscured long GRBs, except in fluence, for which observational biases and inconsistent classification may influence the dark GRB distribution. Additionally, we find that A  V,GRB is not related to a uniform distribution of dust throughout the host, nor to the extremely local environment of the burst, indicating that a larger-scale patchy dust distribution is the cause of the high line-of-sight extinction. Since radio observations are invaluable to revealing heavily dust-obscured GRBs, we make predictions for the detection of radio emission from host star formation with the next-generation VLA.

Keywords: Gamma-ray bursts, High energy astrophysics, Galaxy environments, Radio sources, Radio transient sources
Common Envelope Mass Ejection in Evolved Stars: Modeling the Dust Emission from Post-RGB Stars in the LMC. Common envelope (CE) systems are the result of Roche lobe overflow in interacting binaries. The subsequent evolution of the CE, its ejection, and the formation of dust in its ejecta while the primary is on the red giant branch (RGB) gives rise to a recently identified evolutionary class-dusty post-RGB stars. Their spectral energy distributions (SEDs) suggest that their mass-ejecta are similar to dusty post-asymptotic giant branch (post-AGB) stars. We have modeled the SEDs of a select sample of post-RGB and post-AGB stars in the Large Magellanic Cloud, quantified the total dust mass (and gas mass assuming gas-to-dust ratio) in the disks and shells and set constraints on the dust grain compositions and sizes. We find that the shell masses in the post-RGBs are generally less than those in post-AGBs, with the caveat that substantial amount of mass in both types of objects may lie in cold, extended shells. Our models suggest that circumstellar disks, when present, are geometrically thick structures with a substantial opening angle, consistent with numerical simulations of CE evolution (CEE). Comparison of our model dust masses with the predictions of dust production during CEE on the RGB suggest that CEE occurred near or at the tip of the RGB for our post-RGB sources. A surprising result is that some post-RGB stars harbor carbon-rich dust, believed to form when C/O &gt; 1, e.g., following triple-alpha nucleosynthesis and third dredge-up events in AGB stars. This anomaly strengthens the hypothesis that dusty post-RGBs are born in binary systems.

Keywords: Circumstellar dust
Short GRB Host Galaxies. I. Photometric and Spectroscopic Catalogs, Host Associations, and Galactocentric Offsets. We present a comprehensive optical and near-infrared census of the fields of 90 short gamma-ray bursts (GRBs) discovered in 2005-2021, constituting all short GRBs for which host galaxy associations are feasible (≍60% of the total Swift short GRB population). We contribute 274 new multi-band imaging observations across 58 distinct GRBs and 26 spectra of their host galaxies. Supplemented by literature and archival survey data, the catalog contains 542 photometric and 42 spectroscopic data sets. The photometric catalog reaches 3σ depths of ≳24-27 mag and ≳23-26 mag for the optical and near-infrared bands, respectively. We identify host galaxies for 84 bursts, in which the most robust associations make up 56% (50/90) of events, while only a small fraction, 6.7%, have inconclusive host associations. Based on new spectroscopy, we determine 18 host spectroscopic redshifts with a range of z ≍ 0.15-1.5 and find that ≍23%-41% of Swift short GRBs originate from z &gt; 1. We also present the galactocentric offset catalog for 84 short GRBs. Taking into account the large range of individual measurement uncertainties, we find a median of projected offset of ≍7.7 kpc, for which the bursts with the most robust associations have a smaller median of ≍4.8 kpc. Our catalog captures more high-redshift and low-luminosity hosts, and more highly offset bursts than previously found, thereby diversifying the population of known short GRB hosts and properties. In terms of locations and host luminosities, the populations of short GRBs with and without detectable extended emission are statistically indistinguishable. This suggests that they arise from the same progenitors, or from multiple progenitors, which form and evolve in similar environments. All of the data products are available on the Broadband Repository for Investigating Gamma-Ray Burst Host Traits website.

Keywords: Stellar populations, Gamma-ray bursts, Gravitational wave sources
Short GRB Host Galaxies. II. A Legacy Sample of Redshifts, Stellar Population Properties, and Implications for Their Neutron Star Merger Origins. We present the stellar population properties of 69 short gamma-ray burst (GRB) host galaxies, representing the largest uniformly modeled sample to date. Using the Prospector stellar population inference code, we jointly fit photometry and/or spectroscopy of each host galaxy. We find a population median redshift of $z={0.64}_{-0.32}^{+0.83}$ (68% confidence), including nine photometric redshifts at z ≳ 1. We further find a median mass-weighted age of t  m  = ${0.8}_{-0.53}^{+2.71}$ Gyr, stellar mass of log(M */M ⊙) = ${9.69}_{-0.65}^{+0.75}$ , star formation rate of SFR = ${1.44}_{-1.35}^{+9.37}$ M ⊙ yr-1, stellar metallicity of log(Z */Z ⊙) = $-{0.38}_{-0.42}^{+0.44}$ , and dust attenuation of ${A}_{V}={0.43}_{-0.36}^{+0.85}$ mag (68% confidence). Overall, the majority of short GRB hosts are star-forming (≈84%), with small fractions that are either transitioning (≈6%) or quiescent (≈10%); however, we observe a much larger fraction (≈40%) of quiescent and transitioning hosts at z ≲ 0.25, commensurate with galaxy evolution. We find that short GRB hosts populate the star-forming main sequence of normal field galaxies, but do not include as many high-mass galaxies as the general galaxy population, implying that their binary neutron star (BNS) merger progenitors are dependent on a combination of host star formation and stellar mass. The distribution of ages and redshifts implies a broad delay-time distribution, with a fast-merging channel at z &gt; 1 and a decreased neutron star binary formation efficiency from high to low redshifts. If short GRB hosts are representative of BNS merger hosts within the horizon of current gravitational wave detectors, these results can inform future searches for electromagnetic counterparts. All of the data and modeling products are available on the Broadband Repository for Investigating Gamma-ray burst Host Traits website.

Keywords: Stellar populations, Gamma-ray bursts, Gravitational wave sources
Observation of Gravitational Waves by Invariants for Electromagnetic Waves. We lay a theoretical foundation in the observation of gravitational waves (GWs) by electromagnetic waves (EMWs) performing a full electromagnetic analysis without any optical approximation. For that, the perturbation of plane EMWs is obtained by solving the perturbed Maxwell equation with GWs in the Minkowski background spacetime. In a GW detector using the EMWs, we propose to measure the electromagnetic invariants that are independent of the motion of the EMW receiver and whose perturbations are gauge-invariant. Imposing a physical boundary condition at EMW emitters, we have analytic results for the perturbations of invariants that can be measured in the EMW receiver. Finally, we show antenna patterns of the detector with monochromatic plane GWs and EMWs.

Keywords: Gravitational wave detectors
Tracing PAH Emission in λ-Orionis Using COBE/DIRBE Data. We use archival COBE/DIRBE data to construct a map of polycyclic aromatic hydrocarbon (PAH) emission in the λ-Orionis region. The presence of the 3.3 μm PAH feature within the DIRBE 3.5 μm band and the corresponding lack of significant PAH spectral features in the adjacent DIRBE bands (1.25, 2.2, and 4.9 μm) enable estimation of the PAH contribution to the 3.5 μm data. Having the shortest wavelength of known PAH features, the 3.3 μm feature probes the smallest PAHs, which are also the leading candidates for carriers of anomalous microwave emission (AME). We use this map to investigate the association between the AME and the emission from PAH molecules. We find that the spatial correlation in λ-Orionis is higher between AME and far-infrared dust emission (as represented by the DIRBE 240 μm map) than it is between our PAH map and AME. This finding, in agreement with previous studies using PAH features at longer wavelengths, is in tension with the hypothesis that AME is due to spinning PAHs. However, the expected correlation between mid-infrared and microwave emission could potentially be degraded by different sensitivities of each emission mechanism to local environmental conditions even if PAHs are the carriers of both.

Keywords: Interstellar dust, Dust physics, Polycyclic aromatic hydrocarbons, Interstellar medium
A Machine-learning Approach to Enhancing eROSITA Observations. The eROSITA X-ray telescope, launched in 2019, is predicted to observe roughly 100,000 galaxy clusters. Follow-up observations of these clusters from Chandra, for example, will be needed to resolve outstanding questions about galaxy cluster physics. Deep Chandra cluster observations are expensive, and it is unfeasible to follow up every eROSITA cluster, therefore the objects that are chosen for follow-up must be chosen with care. To address this, we have developed an algorithm for predicting longer-duration, background-free observations, based on mock eROSITA observations. We make use of the hydrodynamic cosmological simulation Magneticum, simulate eROSITA instrument conditions using SIXTE, and apply a novel convolutional neural network to output a deep Chandra-like "super observation" of each cluster in our simulation sample. Any follow-up merit assessment tool should be designed with a specific use case in mind; our model produces observations that accurately and precisely reproduce the cluster morphology, which is a critical ingredient for determining a cluster's dynamical state and core type. Our model will advance our understanding of galaxy clusters by improving follow-up selection, and it demonstrates that image-to-image deep learning algorithms are a viable method for simulating realistic follow-up observations.

Keywords: Galaxy clusters, X-ray astronomy, Neural networks, Observational cosmology, Convolutional neural networks, Astronomy data analysis, X-ray surveys, Astronomical methods, Astronomy image processing
Simulated Bars May Be Shorter but Are Not Slower Than Those Observed: TNG50 versus MaNGA. Galactic bars are prominent dynamical structures within disk galaxies whose size, formation time, strength, and pattern speed influence the dynamical evolution of their hosts' galaxies. Yet, their formation and evolution in a cosmological context is not well understood, as cosmological simulation studies have been limited by the classic trade-off between simulation volume and resolution. Here we analyze barred disk galaxies in the cosmological magnetohydrodynamical simulation TNG50 and quantitatively compare the distributions of bar size and pattern speed to those from MaNGA observations at z = 0. TNG50 galaxies are selected to match the stellar mass and size distributions of observed galaxies, to account for observational selection effects. We find that the high resolution of TNG50 yields bars with a wide range of pattern speeds (including those with ≥ 40 km s-1 kpc-1) and a mean value of ~ 36 km s-1 kpc larger than those from observations by only 6 km s-1 kpc-1, in contrast with previous lower-resolution cosmological simulations that produced bars that were too slow. We find, however, that the bars in TNG50 are on average ~35% shorter than observed, although this discrepancy may partly reflect the remaining inconsistencies in the simulation-data comparison. This leads to higher values of ${ \mathcal R }\,=\,{R}_{\mathrm{corot}}/{R}_{{\rm{b}}}$ in TNG50, but points to simulated bars being too short rather than too slow. After repeating the analysis on the lower-resolution run of the same simulation (with the same physical model), we qualitatively reproduce the results obtained in previous studies: this implies that, along with physical model variations, numerical resolution effects may explain the previously found slowness of simulated bars.

Keywords: Galaxies, Barred spiral galaxies, Disk galaxies
Data-constrained MHD Simulation for the Eruption of a Filament-Sigmoid System in Solar Active Region 11520. The separation of a filament and sigmoid is observed during an X1.4 flare on 2012 July 12 in solar active region 11520, but the corresponding change in magnetic field is not clear. We construct a data-constrained magnetohydrodynamic simulation of the filament-sigmoid system with the flux rope insertion method and magnetic flux eruption code, which produces a magnetic field evolution that may explain the separation of the low-lying filament and high-lying hot channel (sigmoid). The initial state of the magnetic model contains a magnetic flux rope with a hyperbolic flux tube, a null-point structure, and overlying confining magnetic fields. We find that the magnetic reconnections at the null point make the right footpoint of the sigmoid move from one positive magnetic polarity (P1) to another (P3). The tether-cutting reconnection at the hyperbolic flux tube occurs and quickly cuts off the connection of the low-lying filament and high-lying sigmoid. In the end, the high-lying sigmoid erupts and grows into a coronal mass ejection, while the low-lying filament remains stable. The observed double J-shaped flare ribbons, semicircular ribbon, and brightenings of several loops are reproduced in the simulation, where the eruption of the magnetic flux rope includes the impulsive acceleration and propagation phases.

Keywords: Magnetohydrodynamics, Solar magnetic fields, Solar magnetic reconnection, Magnetohydrodynamical simulations
Distances, Radial Distribution, and Total Number of Galactic Supernova Remnants. We present a table of 215 supernova remnants (SNRs) with distances. New distances are found to SNR G51.26 + 0.11 of 6.6 ± 1.7 kpc using H I absorption spectra and to five other SNRs using maser/molecular cloud associations. We recalculate the distances and errors to all SNRs using a consistent rotation curve and provide errors where they were not previously estimated. This results in a significant distance revisions for 20 SNRs. Because of observational constraints and selection effects, there is an apparent deficit of observed number of Galactic SNRs. To investigate this, we employ two methods. The first method applies correction factors for the selection effects to derive the radial density distribution. The second method compares functional forms for the SNR surface density and selection function against the data to find which functions are consistent with the data. The total number of SNRs in the Galaxy is ~3500 (Method 1) or in the range from ~2400 to ~5600 (Method 2). We conclude that the current observed number of SNRs is not yet complete enough to give a well-determined total SNR number or radial density function.

Keywords: Supernova remnants, Galaxy structure, Radio astronomy, H I line emission
Absolute Calibration of Cepheid Period-Luminosity Relations in NGC 4258. Owing to its accurate distance measured from water-maser motions, NGC 4258 is one of the most important anchors for calibrating the Cepheid period-luminosity relations (PLRs). We expand on previous efforts and carry out a new Cepheid search in this system using the Hubble Space Telescope. We discover and measure a sample of 669 Cepheids in four new and two archival NGC 4258 fields, doubling the number of known Cepheids in this galaxy and obtaining an absolute calibration of their optical PLRs. We determine a Wesenheit (W  VI  HST) PLR of $-2.574(\pm 0.034)-3.294(\pm 0.042)\mathrm{log}P$ , consistent with an independent Large Magellanic Cloud (LMC) calibration at the level of 0.032 ± 0.044 mag in its zero-point, after accounting for a metallicity dependence of -0.20 ± 0.05 mag dex-1. Our determination of the PLR slope also agrees with the LMC-based value within their uncertainties. We attempt to characterize the metallicity effect of Cepheid PLRs using only the NGC 4258 sample, but a relatively narrow span of abundances limits our sensitivity and yields a W  VI  HST zero-point dependence of -0.07 ± 0.21 mag dex-1. The Cepheid measurements presented in this study have been used as part of the data to derive the Hubble constant in a companion paper by the SH0ES team.

Keywords: Cepheid variable stars, Cepheid distance
Collimation of the Relativistic Jet in the Quasar 3C 273. The collimation of relativistic jets launched from the vicinity of supermassive black holes (SMBHs) at the centers of active galactic nuclei (AGNs) is one of the key questions to understand the nature of AGN jets. However, little is known about the detailed jet structure for AGN like quasars since very high angular resolutions are required to resolve these objects. We present very long baseline interferometry (VLBI) observations of the archetypical quasar 3C 273 at 86 GHz, performed with the Global Millimeter VLBI Array, for the first time including the Atacama Large Millimeter/submillimeter Array. Our observations achieve a high angular resolution down to ~60 μas, resolving the innermost part of the jet ever on scales of ~105 Schwarzschild radii. Our observations, including close-in-time High Sensitivity Array observations of 3C 273 at 15, 22, and 43 GHz, suggest that the inner jet collimates parabolically, while the outer jet expands conically, similar to jets from other nearby low-luminosity AGNs. We discovered the jet collimation break around 107 Schwarzschild radii, providing the first compelling evidence for structural transition in a quasar jet. The location of the collimation break for 3C 273 is farther downstream from the sphere of gravitational influence (SGI) from the central SMBH. With the results for other AGN jets, our results show that the end of the collimation zone in AGN jets is governed not only by the SGI of the SMBH but also by the more diverse properties of the central nuclei.

Keywords: Quasars, Blazars, Very long baseline interferometry, Relativistic jets, X-ray active galactic nuclei
Plasma Composition Measurements in an Active Region from Solar Orbiter/SPICE and Hinode/EIS. A key goal of the Solar Orbiter mission is to connect elemental abundance measurements of the solar wind enveloping the spacecraft with extreme-UV (EUV) spectroscopic observations of their solar sources, but this is not an easy exercise. Observations from previous missions have revealed a highly complex picture of spatial and temporal variations of elemental abundances in the solar corona. We have used coordinated observations from Hinode and Solar Orbiter to attempt new abundance measurements with the Spectral Imaging of the Coronal Environment (SPICE) instrument, and benchmark them against standard analyses from the EUV Imaging Spectrometer (EIS). We use observations of several solar features in active region (AR) 12781 taken from an Earth-facing view by EIS on 2020 November 10, and SPICE data obtained one week later on 2020 November 17, when the AR had rotated into the Solar Orbiter field of view. We identify a range of spectral lines that are useful for determining the transition region and low-coronal-temperature structure with SPICE, and demonstrate that SPICE measurements are able to differentiate between photospheric and coronal magnesium/neon abundances. The combination of SPICE and EIS is able to establish the atmospheric composition structure of a fan loop/outflow area at the AR edge. We also discuss the problem of resolving the degree of elemental fractionation with SPICE, which is more challenging without further constraints on the temperature structure, and comment on what that can tell us about the sources of the solar wind and solar energetic particles.

Keywords: Atomic spectroscopy, Solar physics, Active sun, Bessel photometry