Sazuna/UAT_keywords huggingface dataset:
A Central TDE Candidate Detected through Spectroscopic Continuum Emission Properties in an SDSS Blue Quasar. In this paper, properties of spectroscopic continuum emissions are considered to detect potential tidal disruption event (TDE) candidates among Sloan Digital Sky Survey (SDSS) quasars. After considering the simple blackbody photosphere model applied to describe quasar continuum emissions with parameters of blackbody temperature TBB and blackbody radius RBB, SDSS quasars and reported optical TDEs occupy distinct regions in the space of TBB and RBB. Then, through the dependence of RBB on TBB for SDSS quasars, 402 outliers in the SDSS Stripe 82 region can be collected. Among the 402 outliers, SDSS J2308 at z = 1.16 is mainly considered, due to its SDSS spectrum observed around the peak brightness of the light curves. With the 7.2 yr long light curves described by the theoretical TDE model, the determined TBB and RBB through its spectroscopic continuum emissions are consistent with the values determined by the TDE model, to support the central TDE. Moreover, considering simulated results on continuum emissions of SDSS quasars around z ∼ 1.16, it can be confirmed at a confidence level higher than 4σ that the continuum emissions of SDSS J2308 are not related to normal quasars. Furthermore, through the simulated results by the accepted continuous autoregressive process to trace intrinsic active galactic nucleus variability, the confidence level higher than 3σ can be confirmed that the long-term light curves of SDSS J2308 are related to a central TDE. The jointed probabilities through both spectroscopic and photometric simulations, the confidence level higher than 5σ can be confirmed to support the central TDE in SDSS J2308.

Keywords: Supermassive black holes, Quasars, Tidal disruption, Transient sources, Emission line galaxies, Active galactic nuclei
Swift-XRT and NuSTAR Monitoring of Obscuration Variability in Mrk 477. We present the analysis of 15 X-ray observations of Mrk 477, a nearby Seyfert 2 active galactic nucleus, with the objective to monitor its obscuring column density variability. The full data set consists of five archival observations, split into two XMM-Newton, two NuSTAR and one Chandra observation, plus two dedicated monitoring campaigns. The monitoring campaigns were performed with Swift-XRT and NuSTAR, containing five observations each. We performed a simultaneous analysis using self-consistent torus models, deriving geometric properties of the torus as well as the obscuration along the line of sight. Mrk 477 is best modeled with a torus with a large covering factor yet low column density (on average). Its line-of-sight column density oscillates between 1.5 and 7 × 1023 cm‑2. Mrk 477 presents frequent obscuring column density variability, on timescales as short as ∼2 weeks. The probability of drawing a pair of obscuration-variable observations for Mrk 477 when having two, three, and four observations is 40%, 78%, and 95%, respectively. Adding the results of this work to those of another 26 sources, we find a trend of increasing obscuration variability with time (from ∼20% at Δt &lt; 10 days, to ∼60%–70% at timescales larger than 5 yr). We discuss whether this is compatible with the majority of obscuration variability coming from broad-line region clouds.

Keywords: X-ray active galactic nuclei, Seyfert galaxies, Active galactic nuclei, High energy astrophysics
LIMFAST. III. Timing Cosmic Reionization with the 21 cm and Near-infrared Backgrounds. The timeline of cosmic reionization remains uncertain despite sustained efforts to study how the ionizing output of early galaxies shaped the intergalactic medium (IGM). Using the seminumerical code LIMFAST, we investigate the prospects for timing the reionization process by cross-correlating the 21 cm signal with the cosmic near-infrared background (NIRB) contributed by galaxies at z &gt; 5. Tracing opposite phases of the IGM on large scales during reionization, the two signals together serve as a powerful probe for the reionization history. However, because long-wavelength, line-of-sight Fourier modes—the only modes probed by NIRB fluctuations—are contaminated by 21 cm foregrounds and thus inevitably lost to foreground cleaning or avoidance, a direct cross correlation of the two signals vanishes. We show that this problem can be circumvented by squaring the foreground-filtered 21 cm signal and cross-correlating the squared field with the NIRB. This statistic is related to the 21 cm–21 cm–NIRB cross bispectrum and encodes valuable information regarding the reionization timeline. Particularly, the 21 cm2 and NIRB signals are positively correlated during the early phases of reionization and negatively correlated at later stages. We demonstrate that this behavior is generic across several different reionization models and compare our simulated results with perturbative calculations. We show that this cross correlation can be detected at high significance by forthcoming 21 cm and NIRB surveys such as the Square Kilometre Array and SPHEREx. Our methodology is more broadly applicable to cross correlations between line intensity mapping data and 2D tracers of the large-scale structure, including photometric galaxy surveys and cosmic microwave background lensing mass maps, among others.

Keywords: Large-scale structure of the universe, Observational cosmology, Intergalactic medium, Reionization, High-redshift galaxies, Cosmic background radiation
On the Temporal Variability of the Galactic Multi-TeV Interstellar Emissions. We use the GALPROP cosmic ray (CR) framework to model the Galactic CR distributions and associated nonthermal diffuse emissions up to PeV energies. We consider ensembles of discrete, finite lifetime CR sources, e.g., supernova remnants, for a range of creation rates and lifetimes. We find that the global properties of the CR sources are likely not directly recoverable from the current "snapshot" of the historic injection and propagation of CRs within the Galaxy that are provided by the data. We show that models for the diffuse γ rays based on the discrete/time-dependent scenarios we consider are able to explain the LHAASO very-/ultra-high-energy (VHE/UHE) γ-ray data with up to 50% contribution by unresolved leptonic sources at the highest energies. Over the models that we consider, variations in the diffuse VHE emissions can be ∼25%, which is comparable to those for the steady-state models that we investigated in an earlier work. Such variations due to the discrete/finite nature of the CR sources are an important factor that are necessary to construct accurate physical models of the diffuse emissions from the Galaxy at VHE/UHEs.

Keywords: Diffuse radiation, Interstellar emissions, Gamma-rays, Particle astrophysics, Cosmic rays
Hidden in Plain Sight: Searching for Dark Companions to Bright Stars with the Large Binocular Telescope and SHARK-VIS. We report the results from a pilot study to search for black holes and other dark companions in binary systems using direct imaging with SHARK-VIS and the iLocater pathfinder "Lili" on the Large Binocular Telescope. Starting from known single-lined spectroscopic binaries, we select systems with high mass functions that could host dark companions and whose spectroscopic orbits indicate a projected orbital separation ≥30 mas. For this first exploration, we selected four systems (HD 137909, HD 104438, HD 117044, and HD 176695). In each case, we identify a luminous companion and measure the flux ratio and angular separation. However, two of the systems (HD 104438 and HD 176695) are not consistent with simple binary systems and are most likely hierarchical triples. The observed companions rule out a massive compact object for HD 137909, HD 117044, and HD 176695. HD 104438 requires further study because the identified star cannot be responsible for the RV orbit and is likely a dwarf tertiary companion. The SHARK-VIS observation was taken near pericenter, and a second image near apocenter is needed to discriminate between a closely separated luminous secondary and a compact object. When a luminous companion is found, the combination of the RVs and the single SHARK-VIS observation strongly constrains the orbital inclination and the companion mass. Since a single SHARK-VIS observation has a typical on-source observing time of only ∼10 minutes, this a promising method to efficiently identify non-interacting compact object candidates.

Keywords: Spectroscopic binary stars, Direct imaging
HH 270/110 as a Jet/Shear Layer Interaction. New observations obtained with JWST of the protostellar HH 270 jet and the "deflected" HH 110 system show that HH 110 has a morphology of a series of distorted working surfaces. These working surfaces appear to be "deflected versions" of the heads of the incident HH 270 jet. We compute a series of 3D numerical simulations, in which we explore the possible parameters of a shearing environment that could give rise to the deflection of HH 270 into the HH 110 flow. We find that we need quite a high sideways velocity for the streaming environment (∼30 km s‑1) in order to produce the complex structure observed in HH 110. This high velocity would be possible in an environment that has been strongly perturbed by the passage of other outflows.

Keywords: Herbig-Haro objects
Compact [O III] Emission-line Regions ("Green Seeds") in Hα Emitters at Cosmic Noon from JWST Observations. We present a rest-frame optical, spatially resolved analysis of more than 100 Hα emitters (HAEs) at z ∼ 2.2 in the ZFOURGE-CDFS field using NIRCam imaging from the JWST Advanced Deep Extragalactic Survey. The ultradeep, high-resolution data give us maps of the resolved emission-line regions of HAEs with stellar mass ranging from 108 M⊙ to 1010 M⊙. An [O III] emission-line map of each HAE is created from the flux excess in the F150W filter, leading to the discovery of a population of kiloparsec-scale compact emission-line regions ("Green Seeds") with high equivalent widths (EW). We obtain a sample of 128 Green Seeds from 68 HAEs with rest-frame EW[O III] &gt; 200 Å. Moreover, 17 of them have extremely large EW[O III] &gt; 1000 Å, suggesting the possible Lyman continuum leakage from these emission-line regions. Embedded within the host galaxy, many Green Seeds correspond to UV star-forming clumps and H II regions, indicating elevated starburst activity in them, with specific star formation rates several times higher than that of the host galaxy. Based on theoretical frameworks, Green Seeds are expected to be formed through gravitational disk instability and/or galaxy mergers. Considering the stellar masses of Green Seeds, we speculate that high-mass Green Seeds may migrate toward the galactic center to build the central bulge, while low-mass Green Seeds are easily disrupted and short lived. Besides, we propose that some Green Seeds could be the progenitors of globular clusters or ultracompact dwarf galaxies observed in the local Universe.

Keywords: Galaxy colors, Dwarf galaxies, Emission line galaxies, Galaxy evolution, High-redshift galaxies
Supernova Siblings and Spectroscopic Host Galaxy Properties. Over the past century, supernova (SN) searches have detected multiple supernovae (SNe) in hundreds of individual galaxies. So-called SN siblings discovered in the same galaxy present an opportunity to constrain the dependence of the properties of SNe on those of their host galaxies. To investigate whether there is a connection between sibling SNe in galaxies that have hosted multiple SNe and the properties of galaxies, we have acquired integrated optical spectroscopy of 59 galaxies with multiple core-collapse SNe. Perhaps surprisingly, a strong majority of host galaxy spectra fall within the composite region of the Baldwin–Phillips–Terlevich (BPT) diagram. We find a statistically significant difference (Kolmogorov–Smirnov test p-value = 0.044) between the distributions of the [N II] λ6583/Hα of galaxies that have hosted a majority of SNe Ibc and those that have hosted a majority of Type II supernovae (SNe II), where the majority of Type Ibc supernovae (SNe Ibc) galaxies have, on average, higher ratios. The difference between the distributions of [N II] λ6583/Hα may arise from either increased contribution from active galactic nuclei or low-ionization nuclear emission-line regions in SNe Ibc host galaxies, greater metallicity for SNe Ibc host galaxies, or both. When comparing the inferred oxygen abundance and the ionization parameter for the galaxies in the star-forming region on the BPT diagram, we find statistically significant differences between the distributions for SNe Ibc hosts and SNe II hosts (p = 0.008 and p = 0.001, respectively), as well as SNe Ib hosts and SNe II hosts (p = 0.030 and p = 0.006, respectively). We also compare the Hα equivalent width distributions, also integrated across the galaxies, and find no significant difference.

Keywords: Metallicity, Core-collapse supernovae
Habitability in 4D: Predicting the Climates of Earth Analogs across Rotation and Orbital Configurations. Earth-like planets in the circumstellar habitable zone (HZ) may have dramatically different climate outcomes depending on their spin–orbit parameters, altering their habitability for life as we know it. We present a suite of 93 ROCKE-3D general circulation models (GCMs) for planets with the same surface conditions and average annual insolation as Earth, but with a wide range of rotation periods, obliquities, orbital eccentricities, and longitudes of periastra. Our habitability metric fHZ is calculated based on the temperature and precipitation in each model across grid cells over land. Latin hypercube sampling aids in sampling all four of the spin–orbit parameters with a computationally feasible number of GCM runs. Statistical emulation then allows us to model fHZ as a smooth function with built-in estimates of statistical uncertainty. We fit our emulator to an initial set of 46 training runs, then test with an additional 46 runs at different spin–orbit values. Our emulator predicts the directly GCM-modeled habitability values for the test runs at the appropriate level of accuracy and precision. For orbital eccentricities up to 0.225, rotation period remains the primary driver of the fraction of land that remains above freezing and with precipitation above a threshold value. For rotation periods greater than ~20 days, habitability drops significantly (from ~70% to ~20%), driven primarily by cooler land temperatures. Obliquity is a significant secondary factor for rotation periods less than ~20 Earth days, with a factor of 2 impact on habitability that is maximized at intermediate obliquity.

Keywords: Bayesian statistics, Atmospheric circulation, Astrobiology, Planetary climates, Habitable planets
PSR J1231–1411 Revisited: Pulse Profile Analysis of X-Ray Observation. One of the primary goals of Neutron Star Interior Composition Explorer (NICER)-like X-ray missions is to impose stringent constraints on the neutron star equation of state by precisely measuring their masses and radii. NICER has recently expanded the data set of inferred mass–radius relations for neutron stars, including four rotation-powered millisecond pulsars PSR J0030+0451, PSR J0740+6620, PSR J0437–4715, and PSR J1231–1411. In this work, the mass–radius relation and X-ray emitting region properties of PSR J1231–1411 are inferred with an independent pulse profile modeling based on the spherical star Schwarzschild spacetime and Doppler approximation. With one single-temperature elongated hot spot and one single-temperature crescent hot spot, the inferred gravitational mass is M = 1.12 ± 0.07 M⊙ and the inferred equatorial radius is   km (68% credible intervals). It provides an alternative geometry configuration of the X-ray emitting region for PSR J1231–1411 to sufficiently explain the observation data of NICER and XMM-Newton. The inferred radius is smaller than that derived by T. Salmi et al. (  M⊙, Req = 12.6 ± 0.3 km), and the inferred mass is slightly higher in this work. The inferred geometry configurations of the X-ray emitting region in both works are nonantipodal, which is not consistent with a centered dipole magnetic field and suggests a complex magnetic field structure.

Keywords: Neutron stars, X-ray astronomy, High energy astrophysics, Millisecond pulsars, Nuclear astrophysics
A New X-Ray Census of Rotation Powered Pulsars. To date, over 4000 pulsars have been detected. In this study, we identify 231 X-ray counterparts of Australia Telescope National Facility (ATNF) pulsars by performing a spatial cross match across the Chandra, XMM-Newton observational catalogs. This data set represents the largest sample of X-ray counterparts ever compiled, including 98 normal pulsars (NPs) and 133 millisecond pulsars (MSPs). Based on this significantly expanded sample, we re-establish the correlation between X-ray luminosity and spin-down power, given by   across the whole X-ray band. The strong correlation is also observed in hard X-ray band, while in soft X-ray band there is no significant correlation. Furthermore, LX shows a strong correlation with spin period and characteristic age for NPs. For the first time, we observe a strongly positive correlation between LX and the light cylinder magnetic field (Blc) for MSPs, with both NPs and MSPs following the relationship  , consistent with the outer-gap model of pulsars that explains the mechanism of X-ray emission. Additionally, we investigate potential X-ray counterparts for Galactic Plane Pulsar Snapshot pulsars, finding a lower likelihood of detection compared to ATNF pulsars.

Keywords: Neutron stars, Rotation powered pulsars, Pulsars
Estimating Black Hole Masses in Obscured Active Galactic Nuclei from X-Ray and Optical Emission Line Luminosities. We test a novel method for estimating black hole masses (MBH) in obscured active galactic nuclei (AGN) that uses proxies to measure the FWHM of broad Hα (FWHMbHα) and the accretion disk luminosity at 5100 Å (λL5100 Å). Using a published correlation, we estimate FWHMbHα from the narrow optical emission line ratio L[O III]/LnHβ. Using a sample of 99 local obscured AGN from the Swift Burst Alert Telescope AGN Spectroscopic Survey (BASS), we assess the agreement between estimating λL5100 Å from the intrinsic 2 to 10 keV X-ray luminosity and from narrow optical emission lines. We find a mean offset of 0.32 ± 0.68 dex between these methods, which propagates to a factor of ∼2 uncertainty when estimating MBH using a virial mass formula where L[O III]/LnHβ serves as a proxy of FWHMbHα (MBH,[O III]/nHβ). We compare MBH,[O III]/nHβ with virial MBH measurements from broad Paschen emission lines. For the 14 (12) BASS AGN with broad Paα (Paβ) detections, we find MBH,[O III]/nHβ to be systematically higher than MBH,Paα (MBH,Paβ) by a factor of 0.39 ± 0.44 dex (0.48 ± 0.51 dex). Since these offsets are within the scatter, more data are needed to assess whether MBH,[O III]/nHβ is biased high. For 151 BASS AGN with measured stellar velocity dispersions (σ*), we find that the σ*-derived MBH agrees with MBH,[O III]/nHβ to within 0.08 dex, albeit with wide scatter (0.74 dex). The method tested here can provide estimates of MBH in thousands of obscured AGN in spectroscopic surveys when other diagnostics are not available, though with an uncertainty of ∼3–5.

Keywords: X-ray astronomy, Supermassive black holes, Seyfert galaxies, Active galactic nuclei
Mapping Our Path through the Local Interstellar Medium: High-resolution Ultraviolet Absorption Spectroscopy of Sight Lines along the Sun's Historical Trajectory. Using high-resolution UV data obtained from the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we focus on eight sight lines along the Sun's historical trajectory to reconstruct the morphology of our most recent interstellar environment and evaluate its effects on the Sun's heliosphere over the past five million years. Of the eight targets (each within 50 pc), we detect interstellar absorption in six, primarily Mg II and Fe II. We observe C II and O I absorption in target HD 32147. In each analyzed sight line, the Local Interstellar Cloud (LIC) is observed and bears a similar column density. We detected the Blue and Aur clouds, both of which the Sun may have encountered before entering the LIC. In at least one sight line a fourth cloud is detected. Even in this compact sample, we observe variation in absorption across neighboring sight lines, reflecting the complexity of local interstellar medium (ISM) small-scale structure. We report the discovery of an astrosphere around target GJ J173, observable due to excess Lyα absorption caused by interaction between the star's stellar wind and the ISM. Over the past ∼five million years, the Sun spent the majority of the time in a low-density plasma region. We see no evidence of any cold, dense material along the observed sight lines. We present timelines for heliospheric response assuming a range of plausible hydrogen densities (0.1 and 0.2 cm‑3). In both cases, we see the Sun, and the heliosphere, traversing significant density variations in its most recent past and most immediate future.

Keywords: Astrosphere interstellar medium interactions, Heliosphere, Hubble Space Telescope, Ultraviolet spectroscopy, Interstellar medium
Two 100 TeV Neutrinos Coincident with the Seyfert Galaxy NGC 7469. In 2013, the IceCube collaboration announced the detection of a diffuse high-energy astrophysical neutrino flux. The origin of this flux is still largely unknown. The most significant individual source is the close-by Seyfert galaxy NGC 1068 at the 4.2σ level with a soft spectral index. To identify sources based on their counterpart, IceCube releases real-time alerts corresponding to neutrinos with a high probability of astrophysical origin. We report here the spatial coincidence of two neutrino alerts, IC 220424A and IC 230416A, with the Seyfert galaxy NGC 7469 at a distance of 70 Mpc. We evaluate, a posteriori, the chance probability of such a coincidence and discuss this source as a potential neutrino emitter based on its multiwavelength properties and in comparison to NGC 1068 by performing a goodness-of-fit test. A test statistic is derived from a likelihood ratio that includes the neutrino angular uncertainty and the source distance. We apply this test first to a catalog of active galactic nucleus sources and second to a catalog of Seyfert galaxies only. Our a posteriori evaluation excludes the possibility of an accidental spatial coincidence of both neutrinos with the Seyfert galaxy NGC 7469 at the 3.2σ level, leaving open the possibility that either one or both neutrinos originated from the source. To be compatible with nondetections of TeV neutrinos, the source would need to have a hard spectral index.

Keywords: Neutrino astronomy, Seyfert galaxies, X-ray active galactic nuclei, Active galactic nuclei, Particle astrophysics