Sazuna/UAT_keywords huggingface dataset:
The Lockman-SpReSo Project. Spectroscopic Analysis of Type 1 Active Galactic Nuclei. We present the first optical-UV spectral systematic analysis of 30 Type 1 active galactic nuclei selected in the far-infrared and X-ray in the Lockman-SpReSO Survey. The sample of faint objects (mB = 19.6–21.8) covers a large redshift range of 0.33 &gt;z &gt; 4.97 with a high signal-to-noise ratio (∼21 on average). A detailed spectral analysis based on the quasar main-sequence phenomenology prescription was applied to deblend the principal optical-UV emitting regions. Our sample spans a bolometric luminosity range of 44.85 &lt; logLbol &lt; 47.87, absolute B-magnitude of 20.46 &gt;MB &gt; –26.14, BH mass of 7.59 &lt; logMBH &lt; 9.80, and Eddington ratio of –1.70 &lt; logREdd &lt; 0.56. The analysis shows that 18 high-z objects correspond to Population (Pop) B, whereas three low-z fall in Pop A2, B1, and B1+. The remaining eight are candidates to be Pop B and one Pop A object. None of them is an extreme accretor. We looked for tendencies in our sample and compared them with other samples with different selection criteria. Evidence for winds was explored using the C IVλ1549 line half-height centroid c(1/2), finding wind velocities between 941 and ‑1587 km s‑1. This result is consistent with samples with similar ranges of z and MB. The Baldwin effect showed a slope of –0.23 ± 0.03 dex consistent with previous studies. Spectra from 12 objects in our sample were found in the Sloan Digital Sky Survey Data Release 17 database. We applied the same methodology to compare them to our spectra, finding no evidence of variability.

Keywords: Optical astronomy, Active galaxies, Surveys, Quasars
McFACTS I: Testing the LVK AGN Channel with Monte Carlo for AGN Channel Testing and Simulation (McFACTS). Active galactic nuclei (AGNs) are a promising source of the binary black hole mergers observed in gravitational waves with LIGO-Virgo-Kagra (LVK). Constraining the AGN channel allows us to limit AGN parameter space (disk density, size, average lifetime) and nuclear star cluster (NSC) parameter space. Constraints on AGNs and NSCs have implications for Λ cold dark matter models of AGN feedback and models of AGN-driven supermassive black hole merger and growth. Here we present several qualitative studies of the AGN channel using new public, open-source, fast, reproducible code McFACTS (https://github.com/mcfacts/mcfacts): Monte Carlo for AGN channel Testing and Simulation. We demonstrate several important features for testing the AGN channel, including: (i) growth to large-mass intermediate-mass black hole is helped by the presence of migration traps or swamps, (ii) flat BH initial mass functions highlight hierarchical merger features in the mass spectrum, (iii) the (q, χeff) anticorrelation is a strong test of the bias to prograde mergers in the AGN channel, (iv) spheroid encounters can drive a fraction of mergers with high in-plane spin components (χp), (v) a high rate of extreme mass ratio inspirals are driven by an initial population of embedded retrograde BH, and (vi) both LVK and LISA are powerful probes of models of AGN disks and their embedded populations.

Keywords: Intermediate-mass black holes, Supermassive black holes, High energy astrophysics, Quasars, Active galaxies, Stellar mass black holes, Gravitational wave sources, Active galactic nuclei, Gravitational waves, Astrophysical black holes
A Comprehensive Analysis of X-Ray Sources in Terzan 5 Using Chandra Observations. We analyze photometry, spectra, and variability of over 100 faint X-ray sources in the globular cluster Terzan 5, using 737 ks of Chandra data. X-ray colors and spectral fitting allow for clear separation of foreground sources (with less extinction than the cluster), quiescent low-mass X-ray binaries (qLMXBs), and sources with harder spectra. We identify 22 candidate qLMXBs, over twice that found in any other cluster. This is consistent with Terzan 5's stellar interaction rate, the highest among Galactic globular clusters. We do not see qLMXBs dominated by thermal emission below LX ∼ 1032 erg s‑1, though qLMXBs with stronger nonthermal emission could be missed. We find that more than 50% of the qLMXB sources have a neutron star thermal component contributing over 80% of the total luminosity. We report an unusual spectral feature around 1.75 keV in the combined spectrum of Ter 5 X-3. The concentration of the qLMXBs within the cluster is consistent with that of a population of mass 1.46 ± 0.14 M⊙. We identify secure X-ray counterparts to millisecond pulsars Terzan 5 ar and Terzan 5 at, using positional coincidence and orbital X-ray light curves matching those expected for spider pulsars.

Keywords: Globular star clusters, Neutron stars, X-ray astronomy, Millisecond pulsars, X-ray sources, Low-mass x-ray binary stars
Quasiperiodic Oscillation Signatures of Disk Restoration after Type-I X-Ray Bursts from 4U 1636−536. Type-I thermonuclear bursts (TNBs) from neutron star low-mass X-ray binaries (NS LMXBs) originate on the neutron star's surface from the unstable burning of the accreted material. On the other hand, kHz quasiperiodic oscillations (QPOs) are thought to originate in the innermost regions of the inspiralling accretion disk. Type-I TNBs are expected to impact the inner accretion flow, and consequently the kHz QPOs, due to the intense radiation pressure. In this work, we systematically study the evolution of the upper and the lower kHz QPOs immediately before and after a type-I TNB on 4U 1636−536 using AstroSat observations in the 3─20 keV band. The analysis of the power density spectra shows the presence of kHz QPOs within 200 s before the onset of the type-I burst. However, we have not detected any prominent signature of the same within 100─200 s after the burst. The kHz QPOs then reemerge after ≍200 s. The fractional rms variation in the 3─20 keV band drops by ≍5%─6%, supporting the nonexistence of kHz QPOs in the 200 s postburst zone. The timescale of 200 s coincides with the viscous timescale, highlighting a scenario where the inner disk is temporarily disrupted by the intense radiation from the type-I TNB. The kHz QPO then reestablishes as the inner disk is restored.

Keywords: Low-mass x-ray binary stars, X-ray binary stars, Accretion, Stellar accretion disks
Evaluating Mass Outflow Rate Estimators in FIRE-2 Simulations: Toward a Self-consistent Framework for Spectral-line-based Predictions. Galactic outflows shape galaxy evolution, but their mass, energy, and momentum transfer remain uncertain. High-resolution spectroscopy can help, but systematic discrepancies hinder model interpretation. In this study, we evaluate the performance of semianalytical line transfer (SALT) and empirical partial covering models (PCMs) to recover the properties of outflows in the FIRE-2 simulation suite from synthetic Si II lines (1190 Å, 1193 Å, 1260 Å, 1304 Å, 1527 Å). When applicable, we assess each model's ability to recover mass, energy, and momentum outflow rates, as well as radial density and velocity profiles, column densities, and flow geometries. We find that the PCM underestimates column densities by 1.3 dex on average in the range  15&lt;logN[cm‑2]&lt;17  with dispersion 1.3 dex. We attribute this bias to instrumental smoothing. Since the PCM underestimates column densities, it also underestimates flow rates, though its predictions are independent of radius, with a dispersion of 0.55 dex. We detect no bias in the SALT estimates of the column density with dispersion 1.3 dex. When the velocity and density field obey power laws, SALT can constrain the mass, momentum, and energy outflow rates to 0.36(0.63), 0.56(0.56), and 0.97(0.80) dex at 0.15(0.30)Rvir, respectively. However, certain profiles in FIRE-2 fall outside the SALT framework, where the model breaks down. We find that SALT effectively tracks the flow geometry, capturing the temporal evolution of the photon escape fraction that is out of phase with the star formation rate, fully consistent with hydrodynamic simulations. We advocate for integral field unit spectroscopy to better constrain flow properties.

Keywords: Galactic winds, Hydrodynamical simulations, Ultraviolet astronomy, Circumgalactic medium, Radiative transfer simulations
Spatially and Dynamically Extended Molecular Gas in Stephan's Quintet Revealed by ALMA CO(1─0) Total Power Mapping. We present Atacama Large Millimeter/submillimeter Array Total Power CO(1─0) mapping of Stephan's Quintet (SQ), a prototypical compact galaxy group, with a uniform noise level at a spatial scale of ∼25 kpc. These observations provide the first complete view of molecular gas across the whole system. Molecular gas is found to spread over a wide area (∼120 × 80 kpc), mainly over the two main member galaxies (NGC 7318B and 7319), but also in the shocked ridges between these galaxies, the tidal tail, and also in intergalactic regions north of the tail. The total CO(1─0) luminosity is (2.47 ± 0.12) × 109 K km s−1 pc2, corresponding to a molecular gas mass of (1.07 ± 0.05) × 1010 M⊙ assuming the Galactic CO-to-H2 conversion factor. The global star formation efficiency of SQ is estimated at 0.29─0.70 Gyr−1, comparable to or lower than that of nearby star-forming galaxies. Molecular gas spans a velocity range of ∼1300 km s−1, which can be divided into three components (low, mid, and high). The low- and mid-velocity components, linked to NGC 7318B and the ridge, show relatively active star formation, whereas the high-velocity component, associated with NGC 7319, shows suppressed star formation. Our mapping reveals molecular gas extending ∼100 kpc in projection along the inner tail and north of it, containing (1.64 ± 0.08) × 109 M⊙ (15% of total) with low velocity dispersion (∼20 km s−1) and ongoing star formation. While previous studies suggested in situ molecular gas formation in the tail, our data suggest an additional contribution from gas stripped from NGC 7319.

Keywords: Molecular gas, Hickson compact group, Star formation, Galaxy interactions
Modeling Blazar Broadband Emission with Convolutional Neural Networks. III. Proton Synchrotron and Hybrid Models. Modeling the broadband emission of blazars has become increasingly challenging with the advent of multimessenger observations. Building upon previous successes in applying convolutional neural networks (CNNs) to leptonic emission scenarios, we present an efficient CNN-based approach for modeling blazar emission under proton synchrotron and hybrid lepto-hadronic frameworks. Our CNN is trained on extensive numerical simulations generated by SOPRANO, which span a comprehensive parameter space accounting for the injection and all significant cooling processes of electrons and protons. The trained CNN captures complex interactions involving both primary and secondary particles, effectively reproducing electromagnetic and neutrino emissions. This allows for rapid and thorough exploration of the parameter space characteristic of hadronic and hybrid emission scenarios. The effectiveness of the trained CNN is demonstrated through fitting the spectral energy distributions of two prominent blazars, TXS 0506+059 and PKS 0735+178, both associated with IceCube neutrino detections. The modeling is conducted under assumptions of constant neutrino flux across distinct energy ranges, as well as by adopting a fitting that incorporates the expected neutrino event count through a Poisson likelihood method. The trained CNN is integrated into the Markarian Multiwavelength Data Center (www.mmdc.am), offering a robust tool for the astrophysical community to explore blazar jet physics within a hadronic framework.

Keywords: Blazars
Magnetic Field Amplification during a Turbulent Collapse. The question of whether a dynamo can be triggered by gravitational collapse is of great interest, especially for the early Universe. Here, we employ supercomoving coordinates to study the magnetic field amplification from decaying turbulence during gravitational collapse. We perform 3D simulations and show that for large magnetic Reynolds numbers, there can be exponential growth of the comoving magnetic field with conformal time before the decay of turbulence impedes further amplification. The collapse dynamics only affect the nonlinear feedback from the Lorentz force, which diminishes more rapidly for shorter collapse times, allowing nearly kinematic continued growth. We confirm that helical turbulence is more efficient in driving dynamo action than nonhelical turbulence, but this difference decreases for larger collapse times. We also show that for nearly irrotational flows, dynamo amplification is still possible, but it is always associated with a growth of vorticity—even if it still remains very small. In nonmagnetic runs, the growth of vorticity is associated with viscosity and grows with the Mach number. In the presence of magnetic fields, vorticity emerges from the curl of the Lorentz force. During a limited time interval, an exponential growth of the comoving magnetic field with conformal time is interpreted as clear evidence of dynamo action.

Keywords: Magnetic fields
Effect of Matter Accretion on Lithium Enhancement of Giants. A subset of low-mass giants (&lt;2.2 M⊙) exhibit anomalous lithium enhancement behavior, which is still an open topic. Given that more massive giants retain more surface lithium, increasing mass by accreting circumstellar matter could be a channel to enriching lithium. We evaluate this process in the current work. Using the Modules for Experiments in Stellar Astrophysics, we construct a model of matter accretion, including mass loss, that evolves a star from the main-sequence turnoff to the red giant branch tip. The mean accretion rate is estimated from the upper limit of the accreted mass and the evolutionary time of the star during this period, and a grid of accretion rates is constructed. We separately consider their effects on the lithium enhancement of giants, both in terms of the mass and the composition of accretion. Accreting matter with higher lithium abundances has a promoting effect on the lithium enhancement of giants. The accreted matter with excess lithium alleviates the dilution of lithium in the convective envelope during the first dredge-up. The added mass results in lower temperatures at the bottom of the convective envelope, which likewise weaken the depletion of surface lithium. The weak accretion of circumstellar matter is a possible route to lithium enhancement for giants, and it predicts an upper limit on the lithium abundance of ∼2.5 dex. However, the mass increment it requires poses a potential challenge to real astrophysical environments. Such accretion suppresses lithium dilution and depletion of the star during the first dredge-up, thus exhibiting lithium enhancement behavior.

Keywords: Stellar abundances, Stellar evolutionary models, Stellar accretion, Red giant stars, Stellar evolution
Quantifying the Impact of Incompleteness on Identifying and Interpreting Galaxy Protocluster Populations with the TNG-Cluster Simulation. We use the TNG-Cluster simulation to investigate how stellar mass and star formation rate (SFR) incompleteness affect the identification of density peaks within galaxy protoclusters at different redshifts. Our analysis focuses on a sample of 352 protoclusters, defined as the progenitor populations of galaxies that reside within the virialized region of z = 0 clusters with  M200z=0∼1014.2‑15.5M⊙ . For comparison, we define our "baseline" protocluster population as galaxies with M⋆ &gt; 108.5 M⊙ at any redshift. We find that M⋆-limited (M⋆ &gt; 109.5 M⊙) and SFR-limited (SFR &gt; 10 M⊙ yr‑1) subpopulations recover the baseline highest galaxy density peak in roughly ∼60% of cases within an accuracy of 1.0 pMpc (corresponding to an angular scale of  ∼2'‑2.'5 ) at z &gt; 2. This recovery fraction drops to ∼40%‑50% when restricting to galaxies with M⋆ &gt; 1010.0 M⊙. We find that the baseline highest galaxy density peaks typically coincide with the highest dark matter and stellar mass density peaks, with separations less than 0.5 pMpc in ∼60%‑75% of cases at z &gt; 2. This agreement drops to ∼45%‑50% when restricting to galaxies with M⋆ &gt; 1010.0 M⊙. These results indicate that identifying the densest regions of protoclusters—i.e., the core—is highly sensitive to stellar mass and SFR completeness limits. Nevertheless, at z &gt; 2, we find that the baseline highest galaxy density peaks are generally sites of enhanced star formation and accelerated mass growth relative to the remainder of the protocluster, consistent with some observational studies.

Keywords: Hydrodynamical simulations, Galaxy formation, Galaxy environments, Large-scale structure of the universe, High-redshift galaxy clusters, Galaxy evolution
Statistics of Gas Density, Velocity, and Magnetic Fields in Cool-core Galaxy Clusters. Understanding turbulence within the intracluster medium of galaxy clusters is pivotal for comprehending their evolution and dynamics. Employing 3D magnetohydrodynamic simulations of galaxy cluster mergers, we examine the statistical properties of gas density, magnetic fields, and velocity, particularly emphasizing the central regions spanning 400 kpc. The simulations are designed to resemble massive cool-core clusters such as Perseus, while varying the initial plasma β values (100, 200, and 500). Our findings indicate that while the statistical histogram distributions of gas density and velocity appear similar across different β scenarios, their spatial distributions and morphological patterns exhibit noticeable differences. Through the application of the second-order structure function, we identified a scaling relation in velocity fluctuations, characterized by a slope of 1/2 and predominantly dominated by solenoidal components. Furthermore, our analysis reveals a pronounced anisotropy in both velocity and magnetic field fluctuations, with more significant fluctuations along the direction perpendicular to the magnetic fields. This anisotropy is scale-dependent, becoming more pronounced at smaller scales, and exhibits a decreasing trend in scenarios where the magnetic field is relatively weak, particularly at β = 500. This suggests that the anisotropic nature of these fluctuations is predominantly regulated by the magnetic fields. Additionally, we test the efficacy of the synchrotron intensity gradient (SIG) method for tracing magnetic fields in these environments. The SIG shows a global agreement with the magnetic field across all three β scenarios, confirming the SIG's insensitivity to the medium's magnetization level.

Keywords: Galaxy clusters, Magnetohydrodynamics, Extragalactic magnetic fields, Intracluster medium, Magnetohydrodynamical simulations
The Interplay of Parametric and Magnetorotational Instabilities in Oscillatory Shear Flows. The evolution of warped disks is governed by internal, oscillatory shear flows driven by their distorted geometry. However, these flows are known to be vigorously unstable to hydrodynamic parametric instability. In many warped systems, this might coexist and compete with the magnetorotational instability (MRI). The interplay of these phenomena and their combined impact on the internal flows has not been studied. To this end, we perform three-dimensional, magnetohydrodynamic unstratified shearing box simulations with an oscillatory radial forcing function to mimic the effects of a warped disk. In the hydrodynamic study, we find that the parametric instability manifests as strong, vertical "elevator" flows that resist the sloshing motion. Above a critical forcing amplitude, these also emerge in our magnetized runs and dominate the vertical stress, although they are partially weakened by the MRI, and hence the system equilibrates with larger radial sloshing flows. Below this critical forcing, the MRI effectively quenches the parametric instability. In all cases, we find that the internal stresses are anisotropic in character and better described by a viscoelastic relationship with the shearing flows. Unfortunately, these important effects are typically unresolved in global simulations of warped disks and are simplified in analytically tractable models. The incorporation of such complex, warp-amplitude-dependent, viscoelastic stresses will sensitively regulate the laminar flow response and inevitably modify the detailed spatio-temporal evolution of warped systems.

Keywords: Hydrodynamical simulations, Magnetohydrodynamics, Hydrodynamics, Circumstellar disks, Astrophysical fluid dynamics, Magnetohydrodynamical simulations
Massive Black Hole Seed Formation in Strong X-Ray Environments at High Redshift. Direct collapse of pristine gas in early galaxies is a promising pathway for forming supermassive black holes (SMBHs) powering active galactic nuclei at the Epoch of Reionization (EoR). This seeding mechanism requires suppression of molecular hydrogen (H2) cooling during primordial star formation via intense far-ultraviolet radiation from nearby starburst galaxies clustered in overdense regions. However, nondetection of 21 cm signals from the EoR reported by the Hydrogen Epoch of Reionization Array (HERA) experiment suggests that such galaxies may also emit X-rays more efficiently than in the local Universe, promoting H2 production and thereby potentially quenching massive black hole (BH) seed formation. In this study, we examine the thermal and chemical evolution of collapsing gas in dark matter halos using a semi-analytic model incorporating observationally calibrated X-ray intensities. We find that strong X-ray irradiation, as suggested by HERA, significantly suppresses direct collapse and leads most halos to experience H2 cooling. Nevertheless, massive BH seeds with MBH ≳ 104 M⊙ still form by z ≃ 15, particularly in regions with baryonic streaming motion, and their abundance reaches ∼ 10‑4 Mpc‑3, sufficient to explain the SMBHs identified by James Webb Space Telescope spectroscopy at 3 &lt; z &lt; 6. While the formation of highly overmassive BHs with masses comparable to their host galaxies is prohibited by X-ray ionization, our model predicts that BH-to-stellar mass ratios of ≃0.01–0.1 were already established at seeding.

Keywords: Supermassive black holes, Black holes, Quasars, Active galactic nuclei, High-redshift galaxies
The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). XII. Unanchored Forked Stream in the Propagating Path of a Protostellar Outflow. Outflows are key indicators of ongoing star formation. We report the discovery of an unanchored forked stream within the propagating path of an extremely young protostellar outflow in the 70 μm-dark clump G34.74-0.12, based on Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm observations with an angular resolution of 1 .″ 6 (∼5000 au). This outflow originates from a 9.7 M⊙ core, exhibits a fork-shaped stream structure in its redshifted lobe, which is traced by CO (2─1), SiO (5─4), and H2CO (30,3─20,2). It has a momentum of 13 M⊙ km s−1, an energy of 107 M⊙ km2 s−2, and a dynamical timescale of ∼104 yr. Significantly, the enhanced relative abundances of SiO, H2CO, and CH3OH with respect to CO, along with the increased temperature at the forked point, indicate a collisional origin. The forked point does not coincide with any dust continuum core &gt;0.1 M⊙. Moreover, CO (2─1) emission also traces three other outflows in this region, characterized by their masses (0.40, 0.02, and 0.15 M⊙) and momenta (5.2, 0.2, and 1.8 M⊙ km s−1), as part of the ALMA Survey of 70 μm dark High-mass clumps in Early Stages project. All the newly discovered morphological and kinematic features associated with these extremely young protostellar outflows (with timescales of 103─104 yr) suggest that the initial stages of star formation are more complicated than previously understood.

Keywords: Interstellar line emission, Infrared dark clouds, Star forming regions, Star formation, Interstellar medium