Sazuna/UAT_keywords huggingface dataset:
Probing the Extent of Fe Kα Emission in Nearby Active Galactic Nuclei Using Multi-order Analysis of Chandra High Energy Transmission Grating Data. We present a study of the narrow Fe Kα line in seven bright, nearby active galactic nuclei (AGN) that have been observed extensively with the Chandra High Energy Transmission Grating (HETG). The HETG data reveal a wider Fe Kα line in the first-order spectrum than in the second- and third-order spectra, which we interpret as the result of spatially extended Fe Kα emission. We utilize these differences in narrow Fe Kα line widths in the multi-order Chandra HETG spectra to determine the spatial extent and intrinsic velocity width of the emitting material in each object. We find that there is modest evidence for spatially extended emission in each object, corresponding to extension of r ~ 5-100 pc. These distances are significantly larger than those inferred from velocity widths assuming gravitational motions, which give r ~ 0.01-1 pc. This implies either that the gas is emitting at a range of radii, with smaller radii dominating the velocity width and larger radii dominating the spatial extent, or that the gas is exhibiting nongravitational motions, which we suggest would be outflows due to slight excess redshift in the line and velocities that exceed the freefall velocity. We also use the spatial extent information to estimate the mass of the emitting gas by counting fluorescing iron atoms, finding masses on the order of M gas ~ 105-108 M ⊙. Future work with observatories like XRISM will be able to extend this study to a larger number of AGN and decrease uncertainties that arise as a result of the low signal-to-noise ratio of the higher-order HETG data.

Keywords: Supermassive black holes, High energy astrophysics, Seyfert galaxies, X-ray active galactic nuclei, Active galactic nuclei
Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg II h and k Lines. The CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket mission was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of the Mg II h and k spectral region around 2800 Å along a 200″ slit at three locations on the solar disk, achieving the first spatially and spectrally resolved observations of the solar polarization in this near-ultraviolet region. The focus of the work presented here is the center-to-limb variation of the linear polarization across these resonance lines, which is produced by the scattering of anisotropic radiation in the solar atmosphere. The linear polarization signals of the Mg II h and k lines are sensitive to the magnetic field from the low to the upper chromosphere through the Hanle and magneto-optical effects. We compare the observations to theoretical predictions from radiative transfer calculations in unmagnetized semiempirical models, arguing that magnetic fields and horizontal inhomogeneities are needed to explain the observed polarization signals and spatial variations. This comparison is an important step in both validating and refining our understanding of the physical origin of these polarization signatures, and also in paving the way toward future space telescopes for probing the magnetic fields of the solar upper atmosphere via ultraviolet spectropolarimetry.

Keywords: Spectropolarimetry, Center to limb observations, Solar ultraviolet emission, Quiet solar chromosphere, Solar magnetic fields, Solar chromosphere
Massive Protostars in a Protocluster - A Multi-scale ALMA View of G35.20-0.74N.. We present a detailed study of the massive star-forming region G35.2-0.74N with Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm multi-configuration observations. At 0."2 (440 au) resolution, the continuum emission reveals several dense cores along a filamentary structure, consistent with previous ALMA 0.85 mm observations. At 0."03 (66 au) resolution, we detect 22 compact sources, most of which are associated with the filament. Four of the sources are associated with compact centimeter continuum emission, and two of these are associated with H30α recombination line emission. The H30α line kinematics shows the ordered motion of the ionized gas, consistent with disk rotation and/or outflow expansion. We construct models of photoionized regions to simultaneously fit the multiwavelength free-free fluxes and the H30α total fluxes. The derived properties suggest the presence of at least three massive young stars with nascent hypercompact H II regions. Two of these ionized regions are surrounded by a large rotating structure that feeds two individual disks, revealed by dense gas tracers, such as SO2, H2CO, and CH3OH. In particular, the SO2 emission highlights two spiral structures in one of the disks and probes the faster-rotating inner disks. The 12CO emission from the general region reveals a complex outflow structure, with at least four outflows identified. The remaining 18 compact sources are expected to be associated with lower-mass protostars forming in the vicinity of the massive stars. We find potential evidence for disk disruption due to dynamic interactions in the inner region of this protocluster. The spatial distribution of the sources suggests a smooth overall radial density gradient without subclustering, but with tentative evidence of primordial mass segregation.

Keywords: Massive stars, Star forming regions, Stellar accretion disks, Protostars, H II regions
Dark Matter Admixed Neutron Star Properties in the Light of X-Ray Pulse Profile Observations. The distribution of the dark matter (DM) in DM-admixed neutron stars (DANSs) is supposed to result in either a dense dark core or an extended dark halo, subject to the DM fraction of the DANS (f  χ ) and the DM properties, such as the mass (m  χ ) and the strength of the self-interaction (y). In this paper, we perform an in-depth analysis of the formation criterion for dark cores/dark halos, and point out that the relative distribution of these two components is essentially determined by the ratio of the central enthalpy of the DM component to that of the baryonic matter component inside the DANSs. For the critical case where the radii of the DM and the baryonic matter are the same, we further derive an analytical formula to describe the dependence of ${f}_{\chi }^{\mathrm{crit}}$ on m  χ  and y for a given DANS mass. The relative distribution of the two components in DANSs can lead to different observational effects. We here focus on the modification of the pulsar pulse profile, due to the extra light-bending effect in the case of a dark halo existence, and conduct the first investigation into the dark halo effects on the pulse profile. We find that the peak flux deviation is strongly dependent on the ratio of the halo mass to the radius of the DM component. Last, we perform Bayesian parameter estimation on the DM particle properties, based on the recent X-ray observations of PSR J0030+0451 and PSR J0740+6620 by the Neutron Star Interior Composition Explorer.

Keywords: Neutron stars, Dark matter, Pulsars
On the Impact of Relativistic Gravity on the Rate of Tidal Disruption Events. The tidal disruption of stars by supermassive black holes (SMBHs) probes relativistic gravity. In the coming decade, the number of observed tidal disruption events (TDEs) will grow by several orders of magnitude, allowing statistical inferences of the properties of the SMBH and stellar populations. Here we analyze the probability distribution functions of the pericenter distances of stars that encounter an SMBH in the Schwarzschild geometry, where the results are completely analytic, and the Kerr metric. From this analysis we calculate the number of observable TDEs, defined to be those that come within the tidal radius r t but outside the direct capture radius (which is, in general, larger than the horizon radius). We find that relativistic effects result in a steep decline in the number of stars that have pericenter distances r p ≲ 10 r g, where r g = GM/c 2, and that for maximally spinning SMBHs the distribution function of r p at such distances scales as ${f}_{{{\rm{r}}}_{{\rm{p}}}}\propto {r}_{{\rm{p}}}^{4/3}$ , or in terms of β ≡ r t/r p scales as f  β  ∝ β -10/3. We find that spin has little effect on the TDE fraction until the very-high-mass end, where instead of being identically zero the rate is small (≲1% of the expected rate in the absence of relativistic effects). Effectively independent of spin, if the progenitors of TDEs reflect the predominantly low-mass stellar population and thus have masses ≲1M ⊙, we expect a substantial reduction in the rate of TDEs above 107 M ⊙.

Keywords: Black hole physics, Relativistic mechanics, Kerr black holes, Tidal disruption, General relativity, Event horizons
The Massive and Distant Clusters of WISE Survey. XI. Stellar Mass Fractions and Luminosity Functions of MaDCoWS Clusters at z   1. We present stellar mass fractions and composite luminosity functions (LFs) for a sample of 12 clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) in the redshift range 0.951 ≤ z ≤ 1.43. Using spectral energy distribution fitting of optical and deep mid-infrared photometry, we establish the membership of objects along the lines of sight to these clusters and calculate the stellar masses of member galaxies. This allows us to calculate the stellar mass of the clusters much more precisely than in previous works. We find stellar mass fractions for these clusters largely consistent with previous works, and an apparent negative correlation with total cluster mass. We measure a composite 3.6 μm LF down to m* + 2.5 for all 12 clusters. Fitting a Schechter function to the LF, we find a characteristic 3.6 μm magnitude of m* = 19.83 ± 0.12 and faint-end slope of α = -0.81 ± 0.10 for the full sample at a mean redshift of $\bar{z}=1.18$ . We also divide the clusters into high- and low-redshift bins at $\bar{z}=1.29$ and $\bar{z}=1.06$ , respectively, and measure a composite LF for each bin. We see a small, but statistically significant, evolution in m* and α-consistent with passive evolution-when we study the joint fit to the two parameters, which is probing the evolution of faint cluster galaxies at z ~ 1. This highlights the importance of deep IR data in studying the evolution of cluster galaxy populations at high redshift.

Keywords: Galaxy clusters, Galactic and extragalactic astronomy, High-redshift galaxy clusters
Widespread Detection of Two Components in the Hot Circumgalactic Medium of the Milky Way. Surrounding the Milky Way (MW) is the circumgalactic medium (CGM), an extended reservoir of hot gas that has significant implications for the evolution of the MW. We used the HaloSat all-sky survey to study the CGM's soft X-ray emission in order to better define its distribution and structure. We extend a previous HaloSat study of the southern CGM (Galactic latitude b &lt; -30°) to include the northern CGM (b &gt; 30°) and find evidence that at least two hot gas model components at different temperatures are required to produce the observed emission. The cooler component has a typical temperature of kT ~0.18 keV, while the hotter component has a typical temperature of kT ~0.7 keV. The emission measure in both the warm and hot components has a wide range (~0.005-0.03, and ~0.0005-0.004 cm-6 pc, respectively), indicating that the CGM is clumpy. A patch of relatively consistent CGM was found in the north, allowing for the CGM spectrum to be studied in finer detail using a stacked spectrum. The stacked spectrum is well described with a model including two hot gas components at temperatures of kT = 0.166 ± 0.005 keV and kT = ${0.69}_{-0.05}^{+0.04}$ keV. As an alternative to adding a hot component, a neon-enhanced single-temperature model of the CGM was also tested and found to have worse fit statistics and poor residuals.

Keywords: Milky Way Galaxy, Stellar feedback, Circumgalactic medium
Unveiling the Interplay between the GASP Jellyfish Galaxy JO194 and Its Environment with Chandra. X-ray studies of jellyfish galaxies opened a window into the physics of the interplay between the intracluster medium (ICM) and interstellar medium (ISM). In this paper, we present the study of an archival Chandra observation of the GASP jellyfish galaxy JO194. We observe X-ray emission extending from the stellar disk to the unwinding spiral arms with an average temperature of kT = 0.79 ± 0.03 keV. To investigate the origin of the X-ray emission, we compare the observed X-ray luminosities with those expected from the star formation rates (SFRs) obtained from Hα emission. We estimate an X-ray luminosity excess of a factor ~2-4 with respect to the SF; therefore, we conclude that SF is not the main event responsible for the extended X-ray emission of JO194. The metallicity in the spiral arms ( $Z={0.24}_{-0.12}^{+0.19}\,{Z}_{\odot }$ ) is consistent with that of the ICM around JO194 (Z = 0.35 ± 0.07); thus, we suggest that ICM radiative cooling dominates the X-ray emission of the arms. We speculate that the X-ray plasma results from the ISM‒ICM interplay, although the nature of this interplay is still mostly unknown. Finally, we observe that the X-ray properties of JO194 are consistent with those of two other GASP galaxies with different stellar mass, phase-space conditions in their hosting clusters, and local ICM conditions. We suggest that the conditions required to induce extended X-ray emission in jellyfish galaxies are established at the beginning of the stripping, and they can persist on long timescales so that galaxies in different clusters and evolutionary stages can present a similar extended X-ray emission.

Keywords: X-ray astronomy, Galaxy clusters, Galaxy evolution
Velocity-resolved Reverberation Mapping of Changing-look Active Galactic Nucleus NGC 4151 during Outburst Stage: Evidence for Kinematics Evolution of Broad-line Region. Changing-look active galactic nucleus NGC 4151, which has attracted a lot of attention, is undergoing the second dramatic outburst stage in its evolutionary history. To investigate the geometry and kinematics of the broad-line region (BLR), and measure the mass of supermassive black hole in NGC 4151, we perform a 7 month photometric and spectroscopic monitoring program in 2020-2021, using the 2.4 m telescope at Lijiang Observatory. We successfully measure the time lags of the responses from broad Hα, Hβ, Hγ, He I, and He II emission lines to continuum variation, which are ${7.63}_{-2.62}^{+1.85}$ , ${6.21}_{-1.13}^{+1.41}$ , ${5.67}_{-1.94}^{+1.65}$ , ${1.59}_{-1.11}^{+0.86}$ , and ${0.46}_{-1.06}^{+1.22}$ days, respectively, following radial stratification. The ratios of time lags among these lines are 1.23: 1.00: 0.91: 0.26: 0.07. We find that the continuum lag between the ultraviolet and optical bands can significantly affect the lag measurements of He I and He II. Virial and infalling gas motions coexist in this campaign, which is different from previous results, implying the evolutionary kinematics of BLR. Based on our measurements and previous ones in the literature, we confirm that the BLR of NGC 4151 is basically virialized. Finally, we compute the black hole mass through multiple lines, and the measurement from Hβ to be ${3.94}_{-0.72}^{+0.90}\times {10}^{7}{M}_{\odot }$ , which is consistent with previous results. The corresponding accretion rate is ${0.02}_{-0.01}^{+0.01}{L}_{\mathrm{Edd}}{c}^{-2}$ , implying a sub-Eddington accretor.

Keywords: Supermassive black holes, Reverberation mapping, Seyfert galaxies, Active galactic nuclei, Time domain astronomy
FRAMEx. III. Radio Emission in the Immediate Vicinity of Radio-quiet AGNs. We present follow-up results from the first Fundamental Reference AGN Monitoring Experiment (FRAMEx) X-ray/radio snapshot program of a volume-complete sample of local hard X-ray-selected active galactic nuclei (AGNs). Here, we added nine new sources to our previous volume-complete snapshot campaign, two of which are detected in 6 cm Very Long Baseline Array (VLBA) observations. We also obtained deeper VLBA observations for a sample of nine AGNs not detected by our previous snapshot campaign. We recovered three sources with approximately twice the observing sensitivity. In contrast with lower-angular-resolution Very Large Array (VLA) studies, the majority of our sources continue to be undetected with the VLBA. The subparsec radio (6 cm) and X-ray (2-10 keV) emission shows no significant correlation, with L R/L X ranging from 10-8 to 10-4, and the majority of our sample lies well below the fiducial 10-5 relationship for coronal synchrotron emission. Additionally, our sources are not aligned with any of the proposed "fundamental" planes of black hole activity, which purport to unify black hole accretion in the M BH-L X-L R parameter space. The new detections in our deeper observations suggest that the radio emission may be produced by the synchrotron radiation of particles accelerated in low-luminosity outflows. Nondetections may be a result of synchrotron self-absorption at 6 cm in the radio core, similar to what has been observed in X-ray binaries transitioning from the radiatively inefficient state to a radiatively efficient state.

Keywords: Radio active galactic nuclei, Active galaxies, Radio astrometry, X-ray active galactic nuclei
A 30 kpc Spatially Extended Clumpy and Asymmetric Galactic Outflow at z   1.7. We image the spatial extent of a cool galactic outflow with fine-structure Fe II* emission and resonant Mg II emission in a gravitationally lensed star-forming galaxy at z = 1.70347. The Fe II* and Mg II (continuum-subtracted) emissions span out to radial distances of ~14.33 and 26.5 kpc, respectively, with maximum spatial extents of ~21 kpc for Fe II* emission and ~30 kpc for Mg II emission. Mg II emission is patchy and covers a total area of ~184 kpc2, constraining the minimum area covered by the outflowing gas to be ~13% of the total area. Mg II emission is asymmetric and shows ~21% more extended emission along the decl. direction. We constrain the covering fractions of the Fe II* and Mg II emission as a function of radial distance and characterize them with a power-law model. The Mg II 2803 emission line shows two kinematically distinct emission components and may correspond to two distinct shells of outflowing gas with a velocity separation of ∆v ~ 400 km s-1. By using multiple images with different magnifications of the galaxy in the image plane, we trace the Fe II* and Mg II emissions around three individual star-forming regions. In all cases, both the Fe II* and Mg II emissions are more spatially extended compared to the star-forming regions traced by the [O II] emission. These findings provide robust constraints on the spatial extent of the outflowing gas and, combined with outflow velocity and column density measurements, will give stringent constraints on mass-outflow rates of the galaxy.

Keywords: Starburst galaxies, Circumgalactic medium, Galaxy evolution, Galactic and extragalactic astronomy
The Atari Disk, a Metal-poor Stellar Population in the Disk System of the Milky Way. We have developed a chemodynamical approach to assign 36,010 metal-poor SkyMapper stars to various Galactic stellar populations. Using two independent techniques (velocity and action space behavior), Gaia EDR3 astrometry, and photometric metallicities, we selected stars with the characteristics of the "metal-weak" thick-disk population by minimizing contamination by the canonical thick disk or other Galactic structures. This sample comprises 7127 stars, spans a metallicity range of -3.50 &lt; [Fe/H] &lt; -0.8, and has a systematic rotational velocity of &lt;V  ϕ &gt; = 154 km s-1 that lags that of the thick disk. Orbital eccentricities have intermediate values between typical thick-disk and halo values. The scale length is ${h}_{R}={2.48}_{-0.05}^{+0.05}$ kpc, and the scale height is ${h}_{Z}={1.68}_{-0.15}^{+0.19}$ kpc. The metallicity distribution function is well fit by an exponential with a slope of ${\rm{\Delta }}\mathrm{log}N/{\rm{\Delta }}[\mathrm{Fe}/{\rm{H}}]=1.13\,\pm \,0.06$ . Overall, we find a significant metal-poor component consisting of 261 SkyMapper stars with [Fe/H] &lt; -2.0. While our sample contains only 11 stars with [Fe/H] ≲ -3.0, investigating the JINAbase compilation of metal-poor stars reveals another 18 such stars (five have [Fe/H] &lt; -4.0) that kinematically belong to our sample. These distinct spatial, kinematic, and chemical characteristics strongly suggest that this metal-poor, phase-mixed kinematic sample represents an independent disk component with an accretion origin in which a massive dwarf galaxy radially plunged into the early Galactic disk. Going forward, we propose to call the metal-weak thick-disk population the Atari disk, given its likely accretion origin, and in reference to it sharing space with the Galactic thin and thick disks.

Keywords: Galaxy formation, Galaxy structure, Galaxy dynamics, Galaxy disks, Galaxy abundances, Galaxy kinematics
The Details of Limb Brightening Reveal the Structure of the Base of the Jet in M87 for the First Time. It has become commonplace in astronomy to describe the transverse coarse structure of jets in loosely defined terms such as "sheath" and "spine" based on discussions of parsec scale properties. But, the applicability, dimension, and prominence of these features on sub-light-year scales has previously been unconstrained by observation. The first direct evidence of jet structure near the source in M87 is extreme limb brightening (a double-rail morphology), 0.3-0.6 mas from the source, which is prominent in observations with high resolution and sensitivity. Intensity crosscuts of these images provide three strong, interdependent constraints on the geometry responsible for the double-rail morphology: the rail to rail separation, the peak to trough intensity ratio, and the rail widths. Analyzing these constraints indicates that half or more of the jet volume resides in a thick-walled, tubular, mildly relativistic, protonic jet only ~0.25 lt-yr (or ~300 M, where M is the central black hole mass in geometrized units) from the source. By contrast, the Event Horizon Telescope Collaboration interprets their observations with the aid of general relativistic magnetohydrodynamic simulations that produce an invisible (by construction) jet with a surrounding luminous, thin sheath. Yet, it is shown that synthetic images of simulated jets are center brightened 0.3-0.6 mas from the source. This serious disconnection with observation occurs in a region previously claimed in the literature to be well represented by the simulations. The limb brightening analysis motivates a discussion of possible simulation modifications to improve conformance with observations.

Keywords: Galaxy jets, Relativistic jets, Radio jets