Sazuna/UAT_keywords huggingface dataset:
Early Planet Formation in Embedded Disks (eDisk). XVII. A Compact but Structured Keplerian Disk and Large-scale Streamers Revealed in the Class I Protostellar System IRAS 04169+2702. We present high-resolution (∼0 .″ 05; 8 au) dust continuum and molecular line observations toward the Class I protostellar system IRAS 04169+2702 in the Taurus B213 region, as part of the Atacama Large Millimeter/submillimeter Array Large Program Early Planet Formation in Embedded Disks. The 1.3 mm dust continuum emission traces a circumstellar disk with a central depression toward the protostar. Our Karl G. Jansky Very Large Array observations of the same target reveal a single central peak dominated by free─free emission, which coincides with the depression of the thermal dust emission. The mean spectral index of the thermal dust emission from 1.3 mm to 1.4 cm is approximately 2.8, suggestive of the presence of grains grown to millimeter or centimeter sizes in the disk. Velocity gradients along the disk's major axis are seen in emission from the 12CO (2─1), 13CO (2─1), and C18O (2─1) molecular lines. The position─velocity diagrams of these lines unveil a Keplerian-rotating disk with a radius of ∼21 au around a 1.3 M⊙ protostar, as well as an infalling and rotating envelope with the angular momentum conserved. In addition to the compact disk, large-scale infalling spiral structures extending up to approximately 1400 au, i.e., streamers, are discovered in C18O (2─1), SO (65─54), and H2CO (30,3─20,2) as well as in the 1.3 mm continuum emission. Notably, in the region closer to the protostar, the spatial coincidence of C18O and SO may indicate the presence of a shock related to accretion through the spiral arms.

Keywords: Accretion, Circumstellar envelopes, Young stellar objects, Star formation, Protoplanetary disks, Low mass stars, Circumstellar disks, Protostars, Circumstellar dust, Circumstellar gas
The Regulated GeAs Cycles with the New <SUP>63</SUP>Ga(p, γ)<SUP>64</SUP>Ge and <SUP>64</SUP>Ge(p, γ)<SUP>65</SUP>As Reaction Rates and Their Impact on the GS 1826−24 Clocked Bursts and SAX J1808.4−3658 Photospheric Radius Expansion Bursts. The 63Ga(p, γ)64Ge and 64Ge(p, γ)65As thermonuclear reactions connect the ZnGa and GeAs cycles by diverting the flow of the rapid proton-capture process from 63Ga to 65As. Changes in these two reaction rates regulate the ZnGa and GeAs cycles and may affect the modeled properties matching with the observed counterparts of a type I X-ray burster. We implement the latest 63Ga(p, γ)64Ge and 64Ge(p, γ)65As reaction rates to the state-of-the-art self-consistent one-dimensional multizone thermohydrodynamic code KEPLER to study the influence of these new reaction rates on the models of the GS 1826−24 clocked burster and SAX J1808.4−3658 photospheric radius expansion burster. Both new reaction rates obtained by Lu et al. are determined from complementing the experimental input with the nuclear spectroscopic information deduced from the full pf-shell space configuration interaction shell model calculations. By constraining the models on reproducing the observed burst peak, light-curve profile, fluence, and recurrence time, we find that the impact of the newly measured proton thresholds and respective proton-capture reactions on the burst light-curve profile of the GS 1826−24 clocked burster is, in fact, not as significant as claimed by Zhou et al. With or without the inclusion of the newly determined reaction rate of the highly influential 22Mg(α, p)25Al reaction, the impact of the new 63Ga(p, γ)64Ge and 64Ge(p, γ)65As reaction rates on SAX J1808.4−3658 photospheric radius expansion bursts is evident. Our finding indicates that the models reproducing the 2002 October epoch of the SAX J1808.4−3658 photospheric radius expansion burster are more sensitive to the uncertainties of thermonuclear reaction rates.

Keywords: Neutron stars, X-ray binary stars, High energy astrophysics, Reaction rates, Computational methods, Low-mass x-ray binary stars, X-ray bursts, X-ray bursters
Global Distribution of the Key Species on the Surface of Europa. The icy surface of Europa is continuously bombarded by ions and electrons from Jupiter's magnetosphere. The bombardment of the particles dissociates water molecules on the surface of Europa and introduces impurities to the icy surface. Such processes lead to the generation of the nonwater species on the surface of Europa. These chemical species are closely related to the chemistry of the icy crust and the subsurface ocean, as well as Europa's habitability. However, our knowledge of the global distribution of these species is limited due to the sparse satellite and telescope observations on Europa. In this study, we combine a Europa plasma model and a chemical-transport model to simulate the global distribution of the key nonwater species on the surface of Europa. The initial results from our model agree well with the existing observations on the distributions of H2SO4 and SO2, but they show a significant discrepancy with the observed distribution of H2O2. Sensitivity tests on the reaction rate coefficients indicate that the simulated global distribution of all three species fits the observations well if the reaction rate coefficients in the ice are reduced by 1 order of magnitude. This finding provides a useful constraint on the rate coefficient of the chemical reactions in the ice. Furthermore, our model predicts that the O2 on the surface ice of Europa is concentrated on the leading hemisphere. The simulated global distribution of the key species on Europa may provide useful guidance for future missions to Europa, such as Europa Clipper and JUICE.

Keywords: Planetary surfaces, Surface processes, Surface composition, Europa, Surface ices, Astrobiology, Planetary magnetospheres, Galilean satellites, Jovian satellites
Machine Learning Classification of COSMOS2020 Galaxies: Quiescent versus Star-forming. Accurately distinguishing between quiescent and star-forming galaxies is essential for understanding galaxy evolution. Traditional methods, such as spectral energy distribution (SED) fitting, can be computationally expensive and may struggle to capture complex galaxy properties. This study aims to develop a robust and efficient machine learning (ML) classification method to identify quiescent and star-forming galaxies within the Farmer COSMOS2020 catalog. We utilized JWST wide-field light cones from the Santa Cruz semianalytical modeling framework to train a supervised ML model, the CatBoostClassifier, using 28 color features derived from eight mutual photometric bands within the COSMOS catalog. The model was validated against a testing set and compared to the SED-fitting method in terms of precision, recall, F1 score, and execution time. Preprocessing steps included addressing missing data, injecting observational noise, and applying a magnitude cut (mch1 &lt; 26 AB) along with a redshift range of 0.2 &lt; z &lt; 3.5 to align the simulated and observational data sets. The ML method achieved an F1 score of 89% for quiescent galaxies, significantly outperforming the SED-fitting method, which achieved 54%. The ML model demonstrated superior recall (88% versus 38%) while maintaining comparable precision. When applied to the COSMOS2020 catalog, the ML model predicted a systematically higher fraction of quiescent galaxies across all redshift bins within 0.2 &lt; z &lt; 3.5 compared to traditional methods like NUVrJ and SED-fitting. This study shows that ML, combined with multiwavelength data, can effectively identify quiescent and star-forming galaxies, providing valuable insights into galaxy evolution. The trained classifier and full classification catalog are publicly available.

Keywords: Starburst galaxies, Quenched galaxies
Constraining Cosmology with Double-source-plane Strong Gravitational Lenses from the AGEL Survey. Double-source-plane strong gravitational lenses (DSPLs), with two sources at different redshifts, are independent cosmological probes of the dark energy equation of state parameter w and the matter density parameter Ωm. We present the lens model for the DSPL AGEL035346−170639 and infer cosmological constraints from this system for flat Λ cold dark matter and flat wCDM cosmologies. From the joint posterior of w and Ωm in the flat wCDM cosmology, we extract the following median values and 1σ uncertainties:  w=−1.52−0.33+0.49  and  Ωm=0.192−0.131+0.305  from AGEL0353 alone. Combining our measurements with two previously analyzed DSPLs, we present the joint constraint on these parameters from a sample of three, the largest galaxy-scale DSPL sample used for cosmological measurement to date. The combined precision of w from three DSPLs is higher by 15% over AGEL0353 alone. Combining DSPL and cosmic microwave background (CMB) measurements improves the precision of w from CMB-only constraints by 39%, demonstrating the complementarity of DSPLs with the CMB. Despite their promising constraining power, DSPLs are limited by sample size, with only a handful discovered so far. Although ongoing and near-future wide-area sky surveys will increase the number of known DSPLs by up to two orders of magnitude, these systems will still require dedicated high-resolution imaging and spectroscopic follow-ups like those presented in this paper. Our ASTRO 3D Galaxy Evolution with Lenses collaboration is undertaking such follow-up campaigns for several newly discovered DSPLs and will provide cosmological measurements from larger samples of DSPLs in the future.

Keywords: Cosmological parameters, Density parameters, Strong gravitational lensing, Observational cosmology, Dark energy
X-Ray Emission Signatures of Galactic Feedback in the Hot Circumgalactic Medium: Predictions from Cosmological Hydrodynamical Simulations. Little is currently known about the physical properties of the hot circumgalactic medium (CGM) surrounding massive galaxies. Next-generation X-ray observatories will enable detailed studies of the hot CGM in emission. To support these future efforts, we make predictions of the X-ray emission from the hot CGM using a sample of 28 ∼Milky Way-mass disk galaxies at z = 0 from seven cosmological hydrodynamical simulation suites incorporating a wide range of galactic feedback prescriptions. The X-ray surface brightness (XSB) morphology of the hot CGM varies significantly across simulations. XSB-enhanced outflows and bubble-like structures are predicted in many galaxies simulated with active galactic nuclei (AGN) feedback and in some stellar-feedback-only galaxies, while other galaxies exhibit more isotropic XSB distributions at varying brightnesses. Galaxies simulated without cosmic-ray physics exhibit radial XSB profiles with similar shapes (∝r−3 within 20─200 kpc), with scatter about this slope likely due to underlying feedback physics. The hot CGM kinematics also differ substantially: velocity maps reveal signatures of bulk CGM rotation and high-velocity biconical outflows, particularly in simulations incorporating AGN feedback. Some stellar-feedback-only models also generate similar AGN-like outflows, which we postulate is due to centrally concentrated star formation. Simulations featuring AGN feedback frequently produce extended temperature enhancements in large-scale galactic outflows, while simulations incorporating cosmic-ray physics predict the coolest CGM due to pressure support being provided by cosmic rays rather than hot CGM. Individually resolved X-ray emission lines further distinguish hot CGM phases, with lower-energy lines (e.g., O VII) largely tracing volume-filling gas, and higher-energy lines (e.g., Fe XVII) highlighting high-velocity feedback-driven outflows.

Keywords: X-ray astronomy, Hydrodynamical simulations, Circumgalactic medium
Sun-as-a-star Analysis of the Solar Eruption Source Region Using Hα Spectroscopic Observations of CHASE. Sun-as-a-star analyses serve as a bridge for comparative studies on solar and stellar activities. To investigate the typical Sun-as-a-star Hα temporal spectral characteristics in solar eruption source regions, we analyzed five different types of solar eruptions, using spectroscopic data from the Chinese Hα Solar Explorer. Because the spatially integral Hα spectrum of the source region is mainly contributed to by emission from heated plasma in flare ribbons and absorption from cold plasma in evolving filaments, we separately analyze the subregions of the source region dominated by different dynamical processes. It is revealed that filament eruptions show emission near the Hα line center, accompanied by blueshifted/redshifted absorption, while flare ribbons show Hα line center emission with red asymmetry and line broadening. Moreover, a special spectral signature likely associated with coronal mass ejections (CMEs) is identified: prominent blueshifted absorption without a clear deceleration phase, along with redshifted absorption, which can be used as a probe when searching stellar CMEs. Furthermore, in the X9.0 flare (SOL2024-10-03T12:18) accompanied by a violent CME, the expected blueshifted signal is not visible in the spatially integral Hα spectra. This suggests that filament-lifting signals associated with CMEs in the source region can be obscured by the simultaneous dominant flare-ribbon emission within the integration region, which may explain the relatively small number of confirmed stellar CMEs observed in Hα. We also find that comparison between the Hα and UV spectral observations can effectively reveal the velocity evolution of erupting filaments and the potential existence of associated CMEs.

Keywords: Solar flares, Solar coronal mass ejections, Stellar flares, Stellar coronal mass ejections, Solar filament eruptions
The Effects of Turbulent Electrical Resistivity on the Response of the Solar Atmosphere to Flare Energy Input. II. Hard X-Ray Spectra, Light Curves, and Spatial Distributions. In A. G. Emslie et al. (Paper I of this series), we examined the hydrodynamic response of the solar atmosphere to the injection of a beam of nonthermal electrons, with particular emphasis on the effects of turbulence on the electrical resistivity of the ambient plasma and so on the ohmic heating rate associated with driving the beam-neutralizing return current. In this work, we use the density and temperature profiles obtained in Paper I to determine the expected variation of X-ray intensity with position in the flare volume. Both nonthermal emission from direct-impact bremsstrahlung of the beam electrons and thermal emission from the hot plasma created by a combination of collisional and return-current ohmic heating are considered, and we also consider different orientations of the flare loop to the observational line of sight. We find that the presence of high levels of turbulence acts in general to attenuate the electron beam in the corona and so diminish the brightness of the direct-impact hard X-ray emission from the chromospheric footpoints, and also to create regions of very high-temperature emission in the corona, thus enhancing the thermal emission from the coronal part of the loop. The relative brightnesses of coronal and footpoint sources are examined for a variety of photon energies and turbulence parameters, and comparison with observations allows significant constraints to be placed on the properties of turbulence in flaring plasmas.

Keywords: Solar atmosphere, Solar flares, Solar coronal loops, Solar x-ray emission, Solar activity
Modeling Cosmological Evolution of Jetted Seyfert Galaxies for z ≲ 10. We use high-resolution cosmological zoom-in simulations to model mechanical and thermal feedback from active galactic nuclei onto the evolution of Seyfert-type galaxies, studying the morphology of central galaxies growing within dark matter (DM) halos with masses log M/M⊙ ∼ 11.8 at z = 0. In Paper I, we focused on the end products at z = 0; here, we analyze evolution for z ≲ 10. Black holes (SMBHs) of ∼106 M⊙ were seeded at z ∼ 9.1 and z ∼ 3.7, producing jets along their spin axes. Obtained SMBH accretion rates vary in the range ∼0.3─10−4 of the Eddington rate. We compared the basic properties of galaxies, such as star formation rate, masses, gas and stellar fractions, bulge-to-disk mass ratios, SMBH masses, etc., over the range of redshifts. Our results indicate that jets and associated overpressured bubbles have substantial effects on Seyfert galaxy evolution, including properties of the interstellar medium and circumgalactic medium (CGM), and even beyond. This feedback can suppress and even quench star formation, reduce stellar mass and gas fraction, modify the bulge-to-disk ratios, drive outflows from galaxies and host DM halos, and metal-enrich the CGM. The jets are largely but not exclusively contained within galaxies. However, overpressured bubbles cross and modify the composition of the CGM and intergalactic medium, their thermodynamic and dynamic state, and generate vorticity. The CGM emerges as a complex region, where the action of galactic outflows and jet-formed bubbles combines with the influx from cosmological filaments and diffuse accretion. Ultimately, the above processes affect the gas balance within the galaxy, its morphology, and gas supply to the SMBH, limiting its growth.

Keywords: AGN host galaxies, Hydrodynamical simulations, Galaxy formation, Relativistic jets, Seyfert galaxies, Circumgalactic medium
Balmer Absorption in Iron Low-ionization Broad Absorption Line Quasars. While C IV is the most common absorption line in broad absorption line quasar spectra, Balmer absorption lines (BALs) are among the rarest. We present analysis of Balmer absorption in a sample of 14 iron low-ionization BAL quasars (FeLoBALQs); eight are new identifications. We measured velocity offset, width, and apparent optical depth. The partial covering that is ubiquitous in BAL quasar spectra alters the measured Balmer optical depth ratios; accounting for this, we estimated the true H(n = 2) column density. We found the anticipated correlation between Eddington ratio and outflow speed, but it is weak in this sample because nearly all of the objects have the low outflow speeds characterizing loitering outflow FeLoBAL quasars, objects that are also found to have low accretion rates. Measurements of dN/dv, the differential column density with respect to the outflow speed, are anticorrelated with the luminosity and Eddington ratio: the strongest absorption is observed at the lowest speeds in the lowest-luminosity objects. The absorption line width is correlated with αoi, the Fλ point-to-point slope between 5100 Å and 3 μm. This parameter is strongly correlated with the Eddington ratio among low-redshift quasars. BALs have been recently found in the spectra of little red dots (LRDs), a class of high-redshift objects discovered by JWST. We note suggestive similarities between LRDs and FeLoBAL quasars in the emission-line shape, the presence of steep reddening and a scattered blue continuum, the lack of hot dust emission, and X-ray weakness.

Keywords: Quasars, Broad-absorption line quasar
What Determines the Brightness of the Magnetically Open Solar Corona?: Insights from Three-dimensional Radiative Magnetohydrodynamic Simulations and Observations. We investigate the relationship between solar coronal holes and open-field regions using three-dimensional radiative magnetohydrodynamic simulations combined with remote-sensing observations from the Solar Dynamics Observatory (SDO). Our numerical simulations reveal that magnetically open regions in the corona can exhibit brightness comparable to quiet regions, challenging the conventional view that open-field regions are inherently dark coronal holes. We find that the coronal brightness is primarily determined by the total energy input from photospheric magnetic activities, such as the small-scale dynamo, rather than differences in dissipative processes within the corona. Using synthesized EUV intensity maps, we show that brightness thresholds commonly used to identify coronal holes may overlook open-field regions, especially at lower spatial resolutions. Observational analysis utilizing SDO Heliospheric and Magnetic Imager and Atmospheric Imaging Assembly synoptic maps supports our simulation results, demonstrating that magnetic field extrapolation techniques, such as the potential field source surface model, are sensitive to the chosen parameters, including the source surface height. We suggest that discrepancies in estimates of open magnetic flux (the "open flux problem") arise both from the modeling assumptions in coronal magnetic field extrapolation and systematic biases in solar surface magnetic field observations. Our findings indicate the need for reconsidering criteria used to identify coronal holes as indicators of open-field regions to better characterize the solar open magnetic flux.

Keywords: Solar coronal heating, Interplanetary magnetic fields, Solar magnetic fields, Solar coronal holes, Magnetohydrodynamical simulations
Synthetic Modeling of Polarized Dust Emission in Intermediate-mass Young Stellar Objects. II. Effects of Radiative Torque Disruption on Dust Grains in Protostellar Jets/Outflows. One possible explanation for the presence of very large grains (VLGs) larger than 10 μm in the inner envelope of intermediate-mass Class 0/I young stellar objects is their migration from the protostellar disk via outflows. To assess whether RATD hinders this grain transport, we conducted numerical modeling of RATD alongside grain dynamics, using gas velocity and density profiles from an MHD simulation of an intermediate Class 0 protostar. Our results show that, when the central luminosity Lcenter is ≥5L⊙, porous grains larger than 1 μm with tensile strengths  Smax∼103-104ergcm−3  are efficiently destroyed by RATD at the outflow within ∼1 yr. This limits the outward migration of VLGs/submillimeter grains and leads submicron grains to dominate a few hundred astronomical unit inside the outflow cavity until Lcenter drops below &lt;5L⊙. In contrast, Lcenter &gt; 20L⊙ is required for RATD significantly affecting aggregate/composite grains with higher  Smax≥105ergcm−3 . We further incorporated RATD into POLARIS under the assumption that grains remain stationary. POLARIS accurately models the disruption for porous grains, but overestimates results for aggregate/composite grains at Lcenter = 100L⊙. At such high luminosities, the destruction of VLGs with  Smax∼103-104ergcm−3  within the outflow cavity wall and inner envelope (after ∼20 yr) can reduce the observed polarization degree along the cavity wall by a factor of 2. However, RATD is not the dominant factor shaping dust polarization; magnetic inclusions, such as iron, play a more significant role.

Keywords: Dust physics, Circumstellar dust, Dust destruction