Sazuna/UAT_keywords huggingface dataset:
A Spatially Resolved Analysis of Star Formation Burstiness by Comparing UV and Hα in Galaxies at z ∼ 1 with UVCANDELS. The UltraViolet imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) program provides Hubble Space Telescope (HST)/UVIS F275W imaging for four CANDELS fields. We combine this UV imaging with existing HST/near-IR grism spectroscopy from 3D-HST+AGHAST to directly compare the resolved rest-frame UV and Hα emission for a sample of 979 galaxies at 0.7 &lt; z &lt; 1.5, spanning a range in stellar mass of 108-11.5 M ⊙. Using a stacking analysis, we perform a resolved comparison between homogenized maps of rest-UV and Hα to compute the average UV-to-Hα luminosity ratio (an indicator of burstiness in star formation) as a function of galactocentric radius. We find that galaxies below stellar mass of ~109.5 M ⊙, at all radii, have a UV-to-Hα ratio higher than the equilibrium value expected from constant star formation, indicating a significant contribution from bursty star formation. Even for galaxies with stellar mass ≳109.5 M ⊙, the UV-to-Hα ratio is elevated toward their outskirts (R/R eff &gt; 1.5), suggesting that bursty star formation is likely prevalent in the outskirts of even the most massive galaxies, but is likely overshadowed by their brighter cores. Furthermore, we present the UV-to-Hα ratio as a function of galaxy surface brightness, a proxy for stellar mass surface density, and find that regions below ~107.5 M ⊙ kpc-2 are consistent with bursty star formation, regardless of their galaxy stellar mass, potentially suggesting that local star formation is independent of global galaxy properties at the smallest scales. Last, we find galaxies at z &gt; 1.1 to have bursty star formation, regardless of radius or surface brightness.

Keywords: Star formation, Galaxy evolution
X-Ray and Near-Infrared Observations of the Middle-aged Pulsar B1055-52, Its Multiwavelength Spectrum, and Proper Motion. Previous observations of the middle-aged γ-ray, X-ray, and radio pulsar B1055-52 indicated some peculiarities, such as a suspected changing of the X-ray flux and spectral parameters, a large excess of the alleged thermal component of the UV spectrum over the Rayleigh-Jeans extension of the X-ray thermal spectrum, and a possible double break in the nonthermal spectral component between the optical and X-ray bands. We observed PSR B1055-52 with the XMM-Newton observatory in X-rays and the Hubble Space Telescope in near-infrared (NIR). The analysis of the XMM-Newton observations does not support the notion of long-term changes in the X-ray flux and broadband X-ray spectrum of the pulsar. Using an observing mode less affected by background noise than the previous XMM-Newton observations, we constrain the power-law (PL) spectral index as ${\alpha }_{X}=-{0.57}_{-0.25}^{+0.26}$ (F  ν  ∝ ν  α ) in the energy band 3-10 keV. From the NIR-optical data we obtain a PL slope α  O  = -0.24 ± 0.10 for the color index E(B - V) = 0.03 mag. The slopes and fluxes of the NIR-optical and X-ray nonthermal spectra suggest that the NIR through X-ray emission can be described by the same PL and is generated by the same mechanism, unlike the pulsar's γ-ray emission. The excess of the UV thermal component over the extension of the X-ray thermal component became smaller but did not disappear, indicating a nonuniformity of the bulk surface temperature. The NIR data also enable us to measure the proper motion accurately, with values μ  α  = 47.5 ± 0.7 mas yr-1 and μ  δ  = -8.7 ± 0.7 mas yr-1. * Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. Based also on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #15676.

Keywords: Neutron stars, Pulsars
The Correlations of Stellar Tidal Disruption Rates with Properties of Massive Black Holes and Their Host Galaxies. Stars can be either disrupted as tidal disruption events (TDEs) or swallowed whole by massive black holes (MBHs) at galactic centers when they approach sufficiently close to these MBHs. In this work, we investigate the correlations of such stellar consumption rates with both the MBH mass M BH and the inner slope of the host-galaxy mass density distribution α. We introduce a simplified analytical power-law model with a power-law stellar-mass density distribution surrounding MBHs and separate the contributions of two-body relaxation and stellar orbital precession for the stellar orbital angular momentum evolution in nonspherical galaxy potentials. The stellar consumption rates derived from this simplified model can be well consistent with the numerical results obtained with a more realistic treatment of stellar distributions and dynamics around MBHs, providing an efficient way to estimate TDE rates. The origin of the correlations of stellar consumption rates with M BH and α is explained by the dependence of this analytical model on those MBH/host-galaxy properties and by the separation of the stellar angular momentum evolution mechanisms. We propose that the strong positive correlation between the rates of stellar consumption due to two-body relaxation and α provides one interpretation for the overrepresentation of TDEs found in some rare E+A/poststarburst galaxies. We find high TDE rates for giant stars, up to those for solar-type stars. Understanding the origin of the correlations of the stellar consumption rates will be necessary for obtaining the demographics of MBHs and their host galaxies via TDEs.

Keywords: Supermassive black holes, High energy astrophysics, Tidal disruption, Galaxy dynamics, Transient sources, Gravitational wave astronomy, Time domain astronomy
Hybrid Data-driven Magnetofrictional and Magnetohydrodynamic Simulations of an Eruptive Solar Active Region. We present the first results of the hybrid data-driven magnetofrictional (MF) and data-constrained magnetohydrodynamic (MHD) simulations of solar active region NOAA 11158, which produced an X-class flare and coronal mass ejection on 2011 February 15. First, we apply the MF approach to build the coronal magnetic configuration corresponding to the SDO/HMI photospheric magnetograms by using the JSOC PDFI_SS electric field inversions at the bottom boundary of the simulation domain. We then use the preeruptive MF state at about 1.5 hr before the observed X-class flare as the initial state for the MHD simulation, assuming a stratified polytropic solar corona. The MHD run shows that the initial magnetic configuration containing twisted magnetic fluxes and a three-dimensional (3D) magnetic null point is out of equilibrium. We find the eruption of a complex magnetic structure consisting of two magnetic flux ropes, as well as the development of flare ribbons, with their morphology being in good agreement with observations. We conclude that the combination of the data-driven MF and data-constrained MHD simulations is a useful practical tool for understanding the 3D magnetic structures of real solar ARs that are unobservable otherwise.

Keywords: Solar coronal mass ejections, Solar flares, Solar filament eruptions, Magnetohydrodynamical simulations
Circumgalactic Lyα Nebulae in Overdense Quasar Pair Regions Observed with the Palomar Cosmic Web Imager. The recent discovery of enormous Lyα nebulae (ELANe), characterized by physical extents &gt;200 kpc and Lyα luminosities &gt;1044 erg s-1, provides a unique opportunity to study the intergalactic medium and circumgalactic medium in distant galaxies. Many existing ELANe detections are associated with local overdensities of active galactic nuclei (AGN). We have initiated a search for ELANe around regions containing pairs of quasi-stellar objects (QSOs) using the Palomar Cosmic Web Imager. The first study of this search, Cai et al., presented results of ELAN0101+0201, which was associated with a QSO pair at z = 2.45. In this study, all targets residing in QSO pair environments analyzed have Lyα detections, but only one of the four targets meets the classification criteria of an ELANe associated with a QSO pair region (z ~ 2.87). The other three sample detections of Lyα nebulae do not meet the size and luminosity criteria to be classified as ELANe. We find kinematic evidence that the ELANe J1613 is possibly powered mostly by AGN outflows. The analysis of circularly averaged surface brightness profiles of emission from the Lyα regions shows that the Lyα emission around z ~ 2 QSO pairs is consistent with emission around individual QSOs at z ~ 2, which is fainter than that around z ~ 3 QSOs. A larger sample of Lyα at z ~ 2 will be needed to determine if there is evidence of redshift evolution when compared to nebular emissions at z ~ 3 from other studies.

Keywords: Quasar-galaxy pairs, Quasars, Intergalactic medium, Active galaxies, Emission nebulae, Active galactic nuclei, Galaxy evolution, Spectroscopy, Nebulae, Lyman-alpha galaxies, Galaxy spectroscopy
Derivation of Instrument Requirements for Polarimetry Using Mg, Fe, and Mn Lines between 250 and 290 nm. Judge et al. recently argued that a region of the solar spectrum in the near-UV between about 250 and 290 nm is optimal for studying magnetism in the solar chromosphere, due to an abundance of Mg II, Fe II, and Fe I lines that sample various heights in the solar atmosphere. In this paper, we derive requirements for spectropolarimetric instruments to observe these lines. We derive a relationship between the desired sensitivity to magnetic field and the signal-to-noise ratio of the measurement from the weak-field approximation of the Zeeman effect. We find that many lines will exhibit observable polarization signals for both longitudinal and transverse magnetic field with reasonable amplitudes.

Keywords: Polarimeters, Solar chromosphere, Spectropolarimetry, Solar instruments
Sgr A* Spin and Mass Estimates through the Detection of an Extremely Large Mass-ratio Inspiral. Estimating the spin of Sagittarius A* (Sgr A*) is one of the current challenges we face in understanding the center of our Galaxy. In the present work, we show that detecting the gravitational waves (GWs) emitted by a brown dwarf inspiraling around Sgr A* will allow us to measure the mass and the spin of Sgr A* with unprecedented accuracy. Such systems are known as extremely large mass-ratio inspirals (XMRIs) and are expected to be abundant and loud sources in our Galactic center. We consider XMRIs with a fixed orbital inclination and different spins of Sgr A* (s) between 0.1 and 0.9. For both cases, we obtain the number of circular and eccentric XMRIs expected to be detected by space-borne GW detectors like LISA and TianQin. We find that if the orbit is eccentric, then we expect to always have several XMRIs in band while for almost circular XMRIs, we only expect to have one source in band if Sgr A* is highly spinning. We later perform a Fisher matrix analysis to show that by detecting a single XMRI the mass of Sgr A* can be determined with an accuracy of the order 10-2 M ⊙, while the spin can be measured with an accuracy between 10-7 and 10-4 depending on the orbital parameters of the XMRI.

Keywords: Milky Way Galaxy physics, Black hole physics, Supermassive black holes, Gravitational waves
Coevolution of Dust and Chemistry in Galaxy Simulations with a Resolved Interstellar Medium. Nearby dwarf irregular galaxies are ideal laboratories for studying the interstellar medium (ISM) at low metallicity, which is expected to be common for galaxies at very high redshift being observed by JWST. We present the first high-resolution (~0.2 pc) hydrodynamical simulations of an isolated low-metallicity (0.1 Z ⊙) dwarf galaxy coupled with a time-dependent chemistry network and a dust evolution model where dust is locally produced and destroyed by various processes. To accurately model carbon monoxide (CO), we post-process the simulations with a detailed chemistry network including the time-dependent effect of molecular hydrogen (H2). Our model successfully reproduces the observed star formation rate and CO(1-0) luminosity (L CO). We find that dust growth in dense gas is required to reproduce the observed L CO otherwise CO would be completely photodissociated. In contrast, the H2 abundance is extremely small and is insensitive to dust growth, leading to a CO-to-H2 conversion factor that is only slightly higher than the Milky Way value despite the low metallicity. An observationally inferred dust-to-gas ratio is thus underestimated if adopting the metallicity-dependent CO-to-H2 conversion factor. The newly produced dust in dense gas mixes with the ISM through supernova feedback without being completely destroyed by sputtering, which leads to galactic outflows 20%-50% dustier than the ISM, providing a possible source for intergalactic dust.

Keywords: Hydrodynamical simulations, Interstellar medium, Astrochemistry
A Unique Low-mass-ratio Contact Eclipsing Binary System under the Period Cutoff. We present a multiband photometric analysis of CRTS J163819.6+03485, the first low-mass-ratio contact binary system with a period of 0.2053321 day under the contact binary period limit. The unprecedented combination of mass ratio and period makes this system unique for eclipsing binary (EB) research. Using new multiband photometric observations, we explored the parameter space of this unique total EB system through a detailed scan in the mass ratio-inclination plane and using the PIKAIA genetic algorithm optimizer. The best set of relative physical parameters and corresponding uncertainties was adopted through Markov Chain Monte Carlo sampling of the parameter space. The resulting mass ratio of the system is q = 0.16 ± 0.01. The absolute parameters were derived by adopting an empirical mass-luminosity relation. Period changes are also investigated by using new observations and archival photometric light curves from massive astronomical surveys, which revealed in a preliminary solution the presence of a possible low-mass tertiary companion. The origin and evolutionary status of the system are investigated through the detached binary formation scenario.

Keywords: Astronomy data modeling, Fundamental parameters of stars, W Ursae Majoris variable stars, Astronomy data analysis, Eclipsing binary stars
JWST UNCOVER: Extremely Red and Compact Object at z <SUB>phot</SUB> ≃ 7.6 Triply Imaged by A2744. Recent JWST/NIRCam imaging taken for the ultra-deep UNCOVER program reveals a very red dropout object at z phot ≃ 7.6, triply imaged by the galaxy cluster A2744 (z d = 0.308). All three images are very compact, i.e., unresolved, with a delensed size upper limit of r  e  ≲ 35 pc. The images have apparent magnitudes of m F444W ~ 25-26 AB, and the magnification-corrected absolute UV magnitude of the source is M UV,1450 = -16.81 ± 0.09. From the sum of observed fluxes and from a spectral energy distribution (SED) analysis, we obtain estimates of the bolometric luminosities of the source of L bol ≳ 1043 erg s-1 and L bol ~ 1044-1046 erg s-1, respectively. Based on its compact, point-like appearance, its position in color-color space, and the SED analysis, we tentatively conclude that this object is a UV-faint dust-obscured quasar-like object, i.e., an active galactic nucleus at high redshift. We also discuss other alternative origins for the object's emission features, including a massive star cluster, Population III, supermassive, or dark stars, or a direct-collapse black hole. Although populations of red galaxies at similar photometric redshifts have been detected with JWST, this object is unique in that its high-redshift nature is corroborated geometrically by lensing, that it is unresolved despite being magnified-and thus intrinsically even more compact-and that it occupies notably distinct regions in both size-luminosity and color-color space. Planned UNCOVER JWST/NIRSpec observations, scheduled in Cycle 1, will enable a more detailed analysis of this object.

Keywords: Reionization, Low-luminosity active galactic nuclei, High-redshift galaxies, Strong gravitational lensing
MIDIS: Strong (Hβ+[O III]) and Hα Emitters at Redshift z ≃ 7-8 Unveiled with JWST NIRCam and MIRI Imaging in the Hubble eXtreme Deep Field. We make use of JWST medium-band and broadband NIRCam imaging, along with ultradeep MIRI 5.6 μm imaging, in the Hubble eXtreme Deep Field to identify prominent line emitters at z ≃ 7-8. Out of a total of 58 galaxies at z ≃ 7-8, we find 18 robust candidates (≃31%) for (Hβ + [O III]) emitters, based on their enhanced fluxes in the F430M and F444W filters, with EW0(Hβ +[O III]) ≃87-2100 Å. Among these emitters, 16 lie in the MIRI coverage area and 12 exhibit a clear flux excess at 5.6 μm, indicating the simultaneous presence of a prominent Hα emission line with EW0(Hα) ≃200-3000 Å. This is the first time that Hα emission can be detected in individual galaxies at z &gt; 7. The Hα line, when present, allows us to separate the contributions of Hβ and [O III] to the (Hβ +[O III]) complex and derive Hα-based star formation rates (SFRs). We find that in most cases [O III]/Hβ &gt; 1. Instead, two galaxies have [O III]/Hβ &lt; 1, indicating that the NIRCam flux excess is mainly driven by Hβ. Most prominent line emitters are very young starbursts or galaxies on their way to/from the starburst cloud. They make for a cosmic SFR density ${\mathrm{log}}_{10}({\rho }_{{\mathrm{SFR}}_{{\rm{H}}\alpha }}/({M}_{\odot }\,{\mathrm{yr}}^{-1}\,{\mathrm{Mpc}}^{-3}))\simeq -2.35$ , which is about a quarter of the total value ( ${\mathrm{log}}_{10}({\rho }_{{\mathrm{SFR}}_{\mathrm{tot}}}/({M}_{\odot }\,{\mathrm{yr}}^{-1}\,{\mathrm{Mpc}}^{-3}))\simeq -1.76$ ) at z ≃ 7-8. Therefore, the strong Hα emitters likely had a significant role in reionization.

Keywords: Starburst galaxies, Galaxy formation, Star formation, Galaxy evolution, Reionization
H I Absorption in Low-power Radio AGNs Detected by FAST. We report the discovery of three H I absorbers toward low-power radio active galactic nuclei (AGNs) in a pilot H I absorption survey with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Compared to past studies, FAST observations have explored lower radio powers by ~0.4 dex and detected these weakest absorbers at given redshifts. By comparing the gas properties and kinematics of sources along radio powers, we aim to explore the interplay between AGN and the surrounding interstellar medium (ISM). Compared to brighter sources at similar redshifts, our observations suggest a slightly lower detection rate of H I absorption lines (~11.5%) in low-power radio AGNs with $\mathrm{log}({P}_{1.4\mathrm{GHz}}/{\rm{W}}\,{\mathrm{Hz}}^{-1})=21.8\mbox{--}23.7$ . The low-power sources with $\mathrm{log}({P}_{1.4\mathrm{GHz}}/{\rm{W}}\,{\mathrm{Hz}}^{-1})\lt 23$ have a lower detection rate of ~6.7%. Due to the incompleteness of the sample, these detection rates may represent the lower limits. The selection of more extended sources and dilution by H I emission at lower redshifts may contribute to the lower detection rate of H I absorption lines. These detected absorbers present relatively narrow line widths and comparable column densities consistent with previous observations. One absorber has a symmetric profile with a large velocity offset, while the other two show asymmetric profiles that can be decomposed into multiple components, suggesting various possibilities of gas origins and kinematics. These H I absorbers may have connections with rotating disks, gas outflows, galactic gas clouds, gas fueling of the AGN, and jet-ISM interactions, which will be further investigated with the upcoming systematic survey and spatially resolved observations.

Keywords: Radio spectroscopy, Active galactic nuclei, Neutral hydrogen clouds
Field-level Neural Network Emulator for Cosmological N-body Simulations. We build a field-level emulator for cosmic structure formation that is accurate in the nonlinear regime. Our emulator consists of two convolutional neural networks trained to output the nonlinear displacements and velocities of N-body simulation particles based on their linear inputs. Cosmology dependence is encoded in the form of style parameters at each layer of the neural network, enabling the emulator to effectively interpolate the outcomes of structure formation between different flat Lambda cold dark matter cosmologies over a wide range of background matter densities. The neural network architecture makes the model differentiable by construction, providing a powerful tool for fast field-level inference. We test the accuracy of our method by considering several summary statistics, including the density power spectrum with and without redshift space distortions, the displacement power spectrum, the momentum power spectrum, the density bispectrum, halo abundances, and halo profiles with and without redshift space distortions. We compare these statistics from our emulator with the full N-body results, the COmoving Lagrangian Acceleration (COLA) method, and a fiducial neural network with no cosmological dependence. We find that our emulator gives accurate results down to scales of k ~ 1 Mpc-1 h, representing a considerable improvement over both COLA and the fiducial neural network. We also demonstrate that our emulator generalizes well to initial conditions containing primordial non-Gaussianity without the need for any additional style parameters or retraining.

Keywords: Large-scale structure of the universe
QUOTAS: A New Research Platform for the Data-driven Discovery of Black Holes. We present QUOTAS, a novel research platform for the data-driven investigation of supermassive black hole (SMBH) populations. While SMBH data-observations and simulations-have grown in complexity and abundance, our computational environments and tools have not matured commensurately to exhaust opportunities for discovery. To explore the BH, host galaxy, and parent dark matter halo connection-in this pilot version-we assemble and colocate the high-redshift, z &gt; 3 quasar population alongside simulated data at the same cosmic epochs. As a first demonstration of the utility of QUOTAS, we investigate correlations between observed Sloan Digital Sky Survey (SDSS) quasars and their hosts with those derived from simulations. Leveraging machine-learning algorithms (ML), to expand simulation volumes, we show that halo properties extracted from smaller dark-matter-only simulation boxes successfully replicate halo populations in larger boxes. Next, using the Illustris-TNG300 simulation that includes baryonic physics as the training set, we populate the larger LEGACY Expanse dark-matter-only box with quasars, and show that observed SDSS quasar occupation statistics are accurately replicated. First science results from QUOTAS comparing colocated observational and ML-trained simulated data at z3 are presented. QUOTAS demonstrates the power of ML, in analyzing and exploring large data sets, while also offering a unique opportunity to interrogate theoretical assumptions that underpin accretion and feedback models. QUOTAS and all related materials are publicly available at the Google Kaggle platform. (The full data set-observational data and simulation data-are available at: https://www.kaggle.com/ and the codes are available at:https://www.kaggle.com/datasets/quotasplatform/quotas)

Keywords: Quasars