Sazuna/UAT_keywords huggingface dataset:
Unveiling the Aromatic and Aliphatic Universe at Redshifts z ∼ 0.2─0.5 with JWST NIRCam/WFSS. Utilizing deep NIRCam/WFSS data from JWST's FRESCO program, we spectroscopically survey the 3.3 μm aromatic and 3.4 μm aliphatic C─H stretching emission bands of polycyclic aromatic hydrocarbon (PAH) molecules in galaxies at redshifts z ∼ 0.2─0.5. Unlike pre-JWST studies, largely limited to infrared (IR)-bright galaxies (LIR ≳ 1011 L⊙) at z ≲ 0.1, we probe 200 galaxies down to LIR ∼ 108.5─1010 L⊙, well beyond the local Universe. The 3.3 μm emission is detected at ≥3σ in 88 out of 187 galaxies, correlating tightly with galaxy IR luminosity and star formation rate (SFR) and confirming the 3.3 μm PAH as a viable SFR tracer. Despite a large scatter, the 3.3 μm─to─IR luminosity ratio (L3.3/LIR) exhibits a strong metallicity dependence with a drop of L3.3/LIR by a factor of ≳10 at 12+log(O/H) ∼ 8.4─8.5 toward lower metallicities. The 3.4 μm emission is detected in 37 out of 159 galaxies, with the 3.4 μm─to─3.3 μm luminosity ratio (L3.4/L3.3) spanning from ∼0.05 to ∼0.58 (median ∼0.19), corresponding to PAH aliphatic fractions of ∼0.78%─8.3% (median ∼2.9%) in terms of fractional carbon atoms in aliphatic units. While L3.4/L3.3 does not depend significantly on redshift, stellar mass, metallicity, or galaxy morphology, it does decrease with various SFR tracers, suggesting that ultraviolet photons in active star-forming regions may strip aliphatic side groups from PAH molecules. Our study showcases the unique power of JWST's NIRCam/WFSS to systematically map PAH aromatic and aliphatic content in statistically significant, less biased galaxy samples, providing critical insights into PAH chemistry and its connection to galaxy properties.

Keywords: Interstellar dust, Dust physics, Starburst galaxies, Polycyclic aromatic hydrocarbons, Spiral galaxies, Galaxy evolution, Infrared galaxies
Generalized Two Thermal Regime Approach: Bipoly Fluid Modeling. The isopoly bifluid approach assumes an isothermal evolution of the solar wind near the Sun up to the radial distance riso, followed by a polytropic evolution constrained by the observed polytropic indices. This approach provides a more accurate model of the interplanetary fluid properties of the solar wind and their radial evolution than Parker's isothermal and polytropic wind. In this article, we present an improvement of the isopoly approach by considering a generalized two thermal regime approach, embedding two distinct polytropic evolutions, the "bipoly" modeling. To demonstrate the capability of the approach, the models are fitted to both interplanetary and coronal observations, all classified by wind speed population in the spirit of M. Maksimovic et al. The set of observations used as constraints are coronal temperatures inferred from charge-state ratio observations from Solar Orbiter, and interplanetary measurements from Helios and Parker Solar Probe. The relaxation of the isothermal criteria in the near-Sun region permits one to significantly improve the fast wind acceleration for low-coronal-temperature conditions. In summary, the new model matches closely the observational constraints: the coronal temperature and the radial evolution of the wind plasma properties in the interplanetary medium, and this for all the wind speed populations.

Keywords: Space plasmas, Solar physics, Solar wind
Radiation Magnetohydrodynamic Simulation of Sub-Eddington Circumbinary Disk around an Equal-mass Massive Black Hole Binary. We present the first three-dimensional radiation magnetohydrodynamic (RMHD) simulation of a sub-Eddington circumbinary disk (CBD) around an equal-mass massive black hole binary with a total mass of 2 × 107 M⊙ on a circular orbit, separated by 100 GMtot/c2. The inclusion of radiation leads to a denser, thinner, and more filamentary disk compared to nonradiative magnetohydrodynamic simulation, primarily due to reduced pressure support and an altered equation of state. The RMHD disk also features ∼3 times lower accretion rate ( ≈0.15ṀEdd ), weaker accretion streams, and a less pronounced overdensity (a.k.a., "lump") at the inner edge. Our analysis of the light curves and thermal spectra reveals that the variability induced by the binary–CBD interaction is distinguishable in the optical/UV band, where CBD shines at about 1% of the Eddington luminosity. These findings underscore the crucial role of radiation on the structure and observational properties of CBDs around massive black hole binaries and have implications for detecting electromagnetic counterparts to Laser Interferometer Space Antenna gravitational-wave precursors, and for heavier binaries that are Pulsar Timing Array sources.

Keywords: Accretion, Supermassive black holes, Black hole physics, Radiative magnetohydrodynamics, Gravitation, Gravitational wave sources
Thermodynamics of the H II Region Sh2-158 and "Direct" Measurement of Its Turbulence. Three SITELLE hyperspectral cubes were used to obtain 12 million spectra sampling 11 emission lines of the H II region Sh2-158. This data set enables the calculation of numerous diagnostics and physical parameters such as abundance, electronic density, temperature, and pressure. The thermodynamic study of the nebula revealed interesting results. From [S II] and [N II] line ratio diagnostics, electronic density and temperature maps were calculated by an iterative computation method. A Monte Carlo analysis was implemented to determine accurate uncertainties for all physical parameters. We thus measured median electronic density and temperature values of 370 cm‑3 and 7020 K from the iterative maps. Examining the global maps and the sampled subregions, complex patterns of density and temperature gradients/variations are observed. We produce an electronic pressure map that shows diminishing pressure, a factor of 10, from the molecular cloud to the outskirts of Sh2-158. Fabry–Perot observations complete the data to further the dynamical analysis of Sh2-158. Supersonic turbulent velocities are "directly" measured from the [N II] 6584 Å. Three statistical tools are used to analyze velocity centroid and nonthermal linewidth maps. The analysis of the velocity fluctuations shows the presence of intermittency. This phenomenon can produce the temperature fluctuations that are suggested to explain the abundance discrepancy problem in H II regions.

Keywords: H II regions, Interstellar medium, Spectroscopy
Newly Discovered Changing-look Active Galactic Nuclei from SDSS and LAMOST Survey. Changing-look active galactic nuclei (CL AGNs) exhibit drastic variations in broad emission lines (BELs), the mechanism of which remains unclear. Expanding the sample of CL AGNs is helpful to reveal the mechanism. This study aims to identify more CL AGNs by crossmatching spectroscopic data from the Sloan Digital Sky Survey and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope. Our approach to identifying CL AGNs is based on automatic spectral fitting, followed by detailed visual inspections. We identify a sample of 51 CL AGNs through this method, in which 40 CL AGNs are newly discovered. Within this sample, 41 CL AGNs primarily show the variability of the Hβ line, nine exhibit obvious changes in both the Hβ and Hα lines, and one source mainly displays variations in the Hα line. Our findings reveal that the sequence of appearance and disappearance of the BELs aligns with the known CL sequence. In addition, we identify 31 candidates exhibiting drastic variations in BELs without accompanying significant photometric variability. We estimate the black hole mass and Eddington ratio for all sources, which range from 2.5 × 106 to 8.0 × 108M⊙ and from 0.001 to 0.13, respectively. Similar to other studies, we also find that the Eddington ratios of CL AGNs and candidates are lower than those of typical AGNs. Our results support the hypothesis that the CL behavior is driven by the state transitions of the accretion disk.

Keywords: Accretion, Supermassive black holes, Quasars, Light curves, Active galactic nuclei
Observational Signatures of Disk Winds in Protoplanetary Disks: Differentiating Magnetized and Photoevaporative Outflows with Fully Coupled Thermochemistry. Magnetized winds and photoevaporative winds are critical in shaping protoplanetary disk evolution. Using 2D axisymmetric (magneto)hydrodynamic simulations with fully coupled thermochemistry, we investigate the signatures of the two winds in CO and [C I] Atacama Large Millimeter/submillimeter Array (ALMA) observations, and examine the potential to distinguish the origins. Our simulations reveal fundamental differences between the two winds: magnetized winds are colder and denser, exhibiting super-Keplerian rotation with small poloidal velocities of ≲1 km s−1 in the atmosphere (z/R ≳ 0.45), while photoevaporative winds are hotter and less dense, exhibiting sub-Keplerian rotation with higher poloidal velocities of several kilometers per second. In addition to previously identified factors like thermal pressure gradient and disk's self-gravity, we demonstrate that magnetic force and advection significantly influence rotational velocities of the gas in the wind, which lead to emission patterns that are distinct from Keplerian rotation in synthetic ALMA observations. Magnetized winds are visible in CO channel maps when wind loss rates are ≳10−8 M⊙ yr−1. When wind loss rates are lower, magnetized winds produce subtle perturbations that resemble those produced by protoplanets. While strong X-ray and ultraviolet radiation photodissociates CO in photoevaporative winds, they can create observable ring-like substructures at disk surfaces. [C I] emission is optically thin and could be most effective at detecting both winds in disks with high gas mass and/or high [C I] abundance. Due to the spatially extended nature of the winds, using a large beam ( ≃0.″4  for disks in nearby star-forming regions) will be helpful regardless of the tracer used.

Keywords: Magnetohydrodynamics, Radio astronomy, Protoplanetary disks, Planet formation
A Systematic Search for Galaxies with Extended Emission Lines and Potential Outflows in JADES Medium-band Images. For the first time, we present a systematic search for galaxies with extended emission lines and potential outflow features using JWST medium-band images in the GOODS South field. This is done by comparing the morphology in medium-band images to adjacent continuum and UV bands. We look for galaxies that have a maximum extent 50% larger, an excess area 30% greater, or an axis ratio difference of more than 0.3 in the medium band compared to the reference bands. After visual inspection, we find 326 candidate galaxies at 1.4 &lt; z &lt; 8.4, with a peak in the population near cosmic noon, benefiting from the good coverage of the medium-band filters. By fitting their spectral energy distributions, we find that the candidate galaxies are at least 20% more bursty in their star-forming activity and have 50% more young stellar populations compared to a control sample selected based on the continuum band flux. Additionally, these candidates exhibit a significantly higher production rate of ionizing photons. We further find that candidates hosting known active galactic nuclei (AGN) produce extended emission that is more anisotropic compared to non-AGN candidates. A few of our candidates have been spectroscopically confirmed to have prominent outflow signatures through NIRSpec observations, showcasing the robustness of the photometric selection. Future spectroscopic follow-up will better help verify and characterize the kinematics and chemical properties of these systems.

Keywords: Galactic winds, High-redshift galaxies, Galaxy classification systems
Pair-instability Gap Black Holes in Population III Star Clusters: Pathways, Dynamics, and Gravitational-wave Implications. The detection of the gravitational-wave (GW) event GW190521 raises questions about the formation of black holes (BHs) within the pair-instability mass gap (PIBHs). We propose that Population III star clusters significantly contribute to events similar to GW190521. We perform N-body simulations and find that PIBHs can form from stellar collisions or binary black hole (BBH) mergers, with the latter accounting for 90% of the contributions. Due to GW recoil during BBH mergers, approximately 10%–50% of PIBHs formed via BBH mergers that escaped from clusters, depending on BH spins and cluster escape velocities. The remaining PIBHs can participate in secondary and multiple BBH formation events, contributing to GW events. Assuming Population III stars form in massive clusters (initially 100,000 M⊙) with a top-heavy initial mass function, the average merger rates for GW events involving PIBHs with 0% and 100% primordial binaries are 0.005 and 0.017 yr‑1 Gpc‑3, respectively, with maximum values of 0.030 and 0.106 yr‑1 Gpc‑3. If Population III stars form in low-mass clusters (initial mass of 1000 M⊙ and 10,000 M⊙), the merger rate is comparable with a 100% primordial binary fraction but significantly lower without primordial binaries. We also calculate the characteristic strains of the GW events in our simulations and find that about 43.4% (LISA), 97.8% (Taiji), and 66.4% (Tianqin) of these events could potentially be detected by space-borne detectors, including LISA, Taiji, and TianQin. Next-generation GW detectors such as DECIGO, the Einstein Telescope, and Cosmic Explorer can nearly cover all these signals.

Keywords: Supernova remnants, Population III stars, N-body simulations, Gravitational wave astronomy
Discovery of the Hybrid Response of Photoionized Gases. Photoionized gases are prevalent throughout the Universe. In such gases, the ion concentration typically exhibits two response modes to radiation: a positive response in the low-ionization state and a negative response in the high-ionization state. Here, we report the discovery of a widespread misalignment at the boundary between the above two response modes and identify a third mode—the hybrid response—through time-dependent photoionization simulations. This phenomenon arises from the asynchrony among the ionization rate, recombination rate, and ion column density. Among these, only the ionization rate can respond instantaneously to changes in radiation. Consequently, the initial rate of change in the column density of Ni ion is given by ‑NiIi + Ni‑1Ii‑1. However, this quantity is typically nonzero at the peak of Ni, leading to a misalignment between the boundaries of positive and negative responses. Such hybrid effects introduce additional complexity in the interpretation of gas properties, highlighting the need for further investigation.

Keywords: Active galaxies, Photoionization, Recombination, Interstellar medium
Broad-line AGNs at 3.5 &lt; z &lt; 6: The Black Hole Mass Function and a Connection with Little Red Dots. We present a sample of 62 Hα detected broad-line active galactic nuclei (BLAGNs) at redshifts 3.5 &lt; z &lt; 6.8 using data from the CEERS and RUBIES surveys. We select these sources directly from JWST/NIRSpec G395M/F290LP spectra. We use a multistep pre-selection and Bayesian fitting to ensure a high-quality sample of sources with broad Balmer lines and narrow forbidden lines. We compute rest-frame ultraviolet and optical spectral slopes for these objects, and determine that 21 BLAGNs in our sample are also little red dots (LRDs). These LRD BLAGNs, when examined in aggregate, show broader Hα line profiles and a higher fraction of broad-to-narrow component Hα emission than non-LRD BLAGNs. We find that ∼90% of LRD BLAGNs are intrinsically reddened (βopt &gt; 0), independent of contributions from emission lines to the broadband photometry. We construct the black hole (BH) mass function at 3.5 &lt; z &lt; 6 after computing robust completeness corrections. This BH mass function shows agreement with recent JWST-based BH mass functions, though we extend these earlier results to log (MBH/M⊙) &lt; 7. The derived BH mass function is consistent with theoretical models, indicating that the observed abundance of BHs in the early Universe may not be discrepant with physically motivated predictions. The BH mass function shape resembles a largely featureless power law, suggesting that signatures from BH seeding have been lost by redshift z ∼ 5─6. Finally, we compute the BLAGN UV luminosity function and find agreement with JWST-detected BLAGN samples from recent works, finding that BLAGN hosts constitute ≲10% of the total observed UV luminosity at all but the brightest luminosities.

Keywords: Supermassive black holes, Black holes, High-redshift galaxy clusters, Quasars, Active galactic nuclei, Broad band photometry, High-redshift galaxies, Astrophysical black holes
Quantifying Uncertainties in Solar Wind Forecasting due to Incomplete Solar Magnetic Field Information. Solar wind forecasting plays a crucial role in space weather prediction, yet significant uncertainties persist duet to incomplete magnetic field observations of the Sun. Isolating the solar wind forecasting errors due to these effects is difficult. This study investigates the uncertainties in solar wind models arising from these limitations. We simulate magnetic field maps with known uncertainties, including far-side and polar field variations, as well as resolution and sensitivity limitations. These maps serve as input for three solar wind models: the Wang–Sheeley–Arge, the Heliospheric Upwind eXtrapolation, and the European Heliospheric FORecasting Information Asset. We analyze the discrepancies in solar wind forecasts, particularly the solar wind speed at Earth's location, by comparing the results of these models to a created ground truth magnetic field map, which is derived from a synthetic solar rotation evolution using the Advective Flux Transport model. The results reveal significant variations within each model with a root mean square error ranging from 59 to 121 km s‑1. Further comparison with the thermodynamic Magnetohydrodynamic Algorithm outside a Sphere model indicates that uncertainties in the different models can lead to even larger variations in solar wind forecasts compared to those within a single model. However, predicting a range of solar wind velocities based on a cloud of points around Earth can help mitigate uncertainties by up to 20%–77%.

Keywords: Space weather, Solar wind, Solar magnetic fields, Heliosphere
Diffuse X-Ray Emission in M51: A Hierarchical Bayesian Spatially Resolved Spectral Analysis. X-ray observations can be used to effectively probe the galactic ecosystem, particularly its hot and energetic components. However, existing X-ray studies of nearby star-forming galaxies are limited by insufficient data statistics and a lack of suitable spectral modeling to account for X-ray emission and absorption geometry. We present results from an X-ray spectral study of M51 using 1.3 Ms Chandra data, the most extensive for such a galaxy. This allows the extraction of diffuse X-ray emission spectra from phase-dependent regions of spiral arms using a logarithmic spiral coordinate system. A hierarchical Bayesian approach analyzes these spectra, testing models from simple single-temperature hot plasma to those including distributed hot plasma and X-ray-absorbing cool gas. We recommend a model that fits the spectra well, featuring a galactic corona with a lognormal temperature distribution and a disk with mixed X-ray emissions and absorption. In this model, only half of the coronal emission is subject to internal absorption. The best-fit column density of absorbing gas is roughly twice that inferred from optical extinction of stellar light. The temperature distribution shows a mean temperature of ∼0.1 keV and an average one-dex dispersion that is enhanced on the spiral arms. The corona's radiative cooling might balance the mechanical energy input from stellar feedback. These results highlight the effectiveness of X-ray mapping of the corona and cool gas in spiral galaxies.

Keywords: X-ray astronomy, Astrostatistics tools, Stellar feedback, Interstellar plasma, Interstellar medium, Circumgalactic medium
Dusty Stellar Source Classification by Implementing Machine Learning Methods Based on Spectroscopic Observations in the Magellanic Clouds. Dusty stellar point sources are a significant stage in stellar evolution and contribute to the metal enrichment of galaxies. These objects can be classified using photometric and spectroscopic observations using color–magnitude diagrams and infrared excesses in spectral energy distributions. We have employed supervised machine learning spectral classification to categorize dusty stellar point sources, including young stellar objects (YSOs) and evolved stars comprising oxygen- and carbon-rich asymptotic giant branch stars (AGBs), red supergiants (RSGs), and post-AGB stars (PAGBs) in the Large and Small Magellanic Clouds, based on spectroscopic labeled data derived from the Surveying the Agents of Galaxy Evolution (SAGE) project, which involved 12 multiwavelength filters and 618 stellar objects. Despite dealing with missing values and uncertainties in the SAGE spectral data sets, we achieved accurate classifications of these sources. To address the challenge of working with small and imbalanced spectral catalogs, we utilized the Synthetic Minority Oversampling Technique (SMOTE), which generates synthetic data points. Subsequently, among all the models applied before and after data augmentation, the probabilistic random forest (PRF) classifier, a tuned random forest, demonstrated the highest total accuracy, reaching 89% based on the recall metric in categorizing dusty stellar sources. In this study, using the SMOTE technique does not improve the accuracy of the best model for the CAGB, PAGB, and RSG classes; it stays at 100%, 100%, and 88%, respectively. However, there are variations in the OAGB and YSO classes. Accordingly, we collected photometrically labeled data with properties similar to the training data set and classified them using the top four PRF models with an accuracy of more than 87%. We also collected multiwavelength data from several studies to classify them using our consensus model, which integrates the four top models to present common labels as the final prediction.

Keywords: Red supergiant stars, Asymptotic giant branch, Small Magellanic Cloud, Large Magellanic Cloud, Asymptotic giant branch stars
Quiet Sun Magnetism from ViSP Data Multiline Inversions Around 630.1 nm. Quiet Sun magnetism plays an important role in the global energy balance of the solar atmosphere. The study of the magnetism of the quiet Sun has been a major effort in the last decades, and, as a result, very important advances in our knowledge have been achieved. The recent commissioning of the Daniel K. Inouye Solar Telescope, the largest ground-based solar telescope in the world today, provides us with data of high spectropolarimetric quality and high spatial resolution. The combination of data acquired with the ViSP instrument on the DKIST telescope around 630.1 nm and multiline inversions enables the achievement of exceptionally high spatial resolution in the solar atmosphere, both at the surface and in depth. In this paper we determine the  log(gf)  values of the spectral lines around 630.1 nm observed with the ViSP instrument and search for the best multi-inversion strategy, by means of MHD simulations, to analyze quiet Sun magnetism data within such spectral range. We present results of quiet Sun magnetism with special emphasis on its evolution with optical depth. In the internetwork, we find the decrease with height of the averaged magnetic field strength and the zone from which the fields become more horizontal. Additionally, we explore the depth-dependent evolution of the network's canopy, uncovering intriguing insights into its thermodynamic and magnetic properties. Notably, we detect a temperature enhancement in very localized areas of the vicinity of the network and distinguish mass motions with opposing velocities inside the flux tubes.

Keywords: Quiet sun, Spectropolarimetry, Solar magnetic fields, Solar physics