Sazuna/UAT_keywords huggingface dataset:
Connecting Environment, Star Formation History, and Morphology of Massive Quiescent Galaxies at 3 &lt; z &lt; 4 with JWST. We present the morphological properties of 17 spectroscopically confirmed massive quiescent galaxies ( 10.2&lt;log(M*/M⊙)&lt;11.2 ) at 3.0 &lt; z &lt; 4.3, observed with JWST/NIRSpec and NIRCam. Using Sérsic profile fits to F277W and F444W imaging, we derive the size─mass relation and find typical sizes of ∼0.6─0.8 kpc at M* = 5 × 1010 M⊙, consistent with ∼7× growth from z ∼ 4 to the present, including ∼2× by z ∼ 2. We find tentative evidence that formation history and morphology jointly influence galaxy sizes: late-forming bulge-dominated galaxies appear more compact by ∼0.2─0.3 dex relative to the expected relation, while late-forming disk-dominated galaxies are larger. Using a Random Forest regressor, we identify local environmental density, quantified by  log(1+δ3')  from the three nearest neighbors, as the strongest predictor of bulge-to-total ratio (B/T), which spans 0.25─1. In the ILLUSTRISTNG simulation, the ex situ stellar mass fraction (f*,ex situ)—a proxy for mergers—is instead the dominant predictor of B/T. Galaxies with high B/T in dense environments show bursty star formation and short quenching timescales (≲0.4 Gyr), consistent with bulge growth through merger-driven starbursts; in simulations, such systems exhibit elevated ex situ fractions (∼20%─30%). In contrast, some high-B/T galaxies in intermediate-density environments have low ex situ fractions, suggesting that additional processes—such as violent disk instabilities—also contribute. These results point to multiple bulge growth pathways at high redshift, unified by rapid gas accretion, central starbursts, and active galactic nucleus feedback, as predicted by cosmological simulations.

Keywords: Galaxy evolution
First Detection of CH<SUB>3</SUB>OD in Prestellar Cores. The isotopic ratios of deuterated methanol derived around protostars are commonly used to infer the physical conditions under which they formed in the earlier prestellar stage. However, there is a discrepancy in the ratio of the singly deuterated methanol isotopologues, CH2DOH/CH3OD, between low- and high-mass protostars, which puts into question whether prestellar isotopic ratios are generally preserved during the star- and planet-forming process. Resolving this puzzle is only made harder by the complete lack of data on this ratio in the prestellar stage. This work presents observations with the IRAM 30 m telescope that securely detect CH3OD in the prestellar core L1448 in Perseus and tentatively in B213-C6 in Taurus. This work constrains the ratio of CH2DOH/CH3OD and the D/H ratios for both singly deuterated methanol isotopologues for the first time at the prestellar stage. Column densities calculated under the assumption of local thermal equilibrium lead to a CH2DOH/CH3OD ratio of 2.8─8.5 in L1448 and ≤5.7 in B213-C6. The values are marginally consistent with the statistically expected ratio of 3, but most assumptions put the values in an elevated range in line with values found around low-mass protostars. The D/H ratio in CH2DOH is between 3.6% and 6.8% in L1448 and in the range of 2.4%─5.8% in B213-C6. The D/H ratio derived for CH3OD is lower, namely, 1.4%─4.4% in L1448 and ≤3.8% in B213-C6.

Keywords: Isotopic abundances, Radio astrometry, Molecular clouds, Astrochemistry
Nonthermal Pressures: Key to Energy Balance and Structure Formation near Sgr A* in the Milky Way. The circumnuclear region of the Galactic center offers a unique laboratory to study energy balance and structure formation around Sgr A⋆. This work investigates thermal and nonthermal processes within a 7 pc distance from Sgr A⋆. Using MeerKAT 1.3 GHz radio continuum data and Atacama Large Millimeter/submillimeter Array H40α radio recombination line emission from the ACES survey, we separate free─free and synchrotron components at ∼0.2 pc resolution. With a thermal fraction of ≃13%, the 1.3 GHz emission shows tight correlations with the Herschel PACS IR data. The correlation between the equipartition magnetic field and molecular gas traced by JCMT 12CO (J = 3 → 2) observations reveals a balance between the magnetic field, cosmic rays, and molecular gas pressures south of the circumnuclear disk on ∼0.7 pc scales. Unlike the magnetic field and ionized gas, the molecular gas density declines in the cavity (R ≤ 2 pc) toward the center, likely due to feedback from Sgr A⋆. We find that nonthermal pressure from turbulent gas nearly balances magnetic and cosmic-ray pressures and exceeds the thermal pressure by 2 orders of magnitude. The medium surrounding Sgr A⋆ is filled by a low-β (thermal-to-magnetic energy ratio), supersonic plasma, with an Alfvén Mach number ≃ 4 (assuming equipartition). Analysis of the mass-to-magnetic flux ratio suggests that the circumnuclear region is mostly subcritical and, therefore, the magnetic field can help stabilize gas clouds against gravitational collapse.

Keywords: Interstellar thermal emission, Galactic center, Star formation
Zangetsu: A Candidate Isolated, Quiescent, and Backsplash Ultra-diffuse Galaxy in the COSMOS Field. Deep imaging surveys have changed our view of the low surface brightness (LSB) Universe. The "renaissance" of the LSB galaxy population, as a prime example of this recent development, continues to challenge our understanding of galaxy formation. Here, we report the serendipitous discovery of Zangetsu, an isolated, quiescent, and distorted ultra-diffuse galaxy (UDG) candidate in the COSMOS field, using images from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Zangetsu exhibits an extremely low central surface brightness (μ0,g = 26.60 ± 0.01 mag arcsec−2), a very shallow inner surface brightness profile (nSersic = 0.40 ± 0.01), and a large angular size (Re ≍ 10 .″ 44). Surprisingly, Zangetsu also has a quiescent stellar population (g − i = 0.96), an unusually elongated shape (b/a ∼ 0.25), and mild morphological asymmetry, making it a rare case among known UDGs. Surface brightness fluctuation analysis of HSC and Hubble Space Telescope images only provides a distance lower limit of D &gt; 25.4 Mpc (thus, Re &gt; 1.38 kpc). However, Zangetsu remains an extreme outlier in the luminosity─size relation of known LSB galaxies, suggesting that it could be an exceptionally large and/or diffuse system. Classic internal or external UDG formation mechanisms alone struggle to explain such a system. A backsplash origin may account for its isolation and quiescent nature. This finding also raises the possibility that current works may overlook similarly extreme, elongated systems that could further our understanding of the LSB Universe.

Keywords: Galaxy structure, Dwarf galaxies, Galaxy photometry, Low surface brightness galaxies
Cascading from the Winds to the Disk: The Universality of Supernovae-driven Turbulence in Different Galactic Interstellar Media. Star-forming galaxies are in a state of turbulence, with one of the principle components of the turbulence sourced by the constant injection of momentum from supernovae (SNe) explosions. Utilizing high-resolution stratified, gravito-hydrodynamical models of SNe-driven turbulence with interstellar medium (ISM) cooling and heating, we explore how SNe-driven turbulence changes across different galactic conditions, parameterized by the galactic mass and potential, SNe driving rate, and seeding functions. We show that, even though the underlying ISM changes between starburst and Milky Way analog models, the velocity fluctuations in the turbulence of both models, but not the kinetic energy fluctuations, can be normalized into a universal, single cascade, du2(k)/dk ∝ k−3/2, where u is the velocity and k is the wave mode, indicating that the structure of the turbulence is robust to significant changes in the ISM and SNe seeding. Moreover, the cascades connect smoothly from the winds into the galactic disk, pushing the outer scale of the turbulence, ℓcor, to over ℓcor ≍ 6ℓ0, where ℓ0 is the gaseous scale height. By providing an analytical model for the sound speed spectrum,  dcs2(k)/dk , in the weak-cooling, adiabatic limit, we show that it is the compressible turbulent modes, uc, that control the volume-filling phase structure of the galactic disks in our models, with  dcs2(k)/dk∝k−2∝duc2(k)/dk . This may indicate that galactic turbulence does not only have highly universal features across different galaxies, but also directly sets the volume-filling hot and warm phase structure of the underlying galactic ISM through turbulent compressible modes.

Keywords: Galactic winds, Interstellar phases, Interstellar dynamics, Interstellar medium, Interstellar medium wind, Astrophysical fluid dynamics, Supernovae, Galaxies
Formation of Free-floating Planets via Ejection: Population Synthesis with a Realistic IMF and Comparison to Microlensing Observations. Microlensing observations suggest that the mass distribution of free-floating planets (FFPs) follows a declining power law with increasing mass. The origin of such distribution is unclear. Using a population synthesis framework, we investigate the formation channel and properties of FFPs, and compare the predicted mass function with observations. Assuming FFPs originate from planet─planet scattering and ejection in single star systems, we model their mass function using a Monte Carlo based planet population synthesis model combined with N-body simulations. We adopt a realistic stellar initial mass function, which naturally results in a large fraction of planetary systems orbiting low-mass stars. The predicted FFP mass function is broadly consistent with observation: it follows the observed power law at higher masses (10 ≲ m/M⊕ &lt; 104), while at lower masses (0.1 &lt; m/M⊕ ≲ 10) it flattens, remaining marginally consistent with the lower bound of the observational uncertainties. Low-mass, close-in planets tend to remain bound, while Neptune-like planets at wide orbits dominate the ejected population due to their large Hill radii and shallow gravitational binding. We also compare the mass distribution of bound planets with microlensing observations and find reasonably good agreement with both surveys. Our model predicts ≃1.20 ejected planets per star in the mass range of 0.33 &lt; m/M⊕ &lt; 6660, with a total FFP mass of ≃17.98 M⊕ per star. Upcoming surveys will be crucial in testing these predictions and constraining the true nature of FFP populations.

Keywords: Exoplanet dynamics, Free floating planets, Planet formation
Transitional Dynamics: Unveiling the Coexistence and Interplay of Type B and Type C Quasiperiodic Oscillations in MAXI J1348-630. Based on broadband timing analysis of Insight-HXMT and Neutron Star Interior Composition Explorer data from the 2019 outburst of the black hole X-ray binary MAXI J1348-630, we report the detection of the coexistence and competitive interplay between Type C and Type B quasiperiodic oscillations (QPOs). Specifically, these two QPO types were detected simultaneously but exhibited distinct energy dependencies: a Type C QPO was dominant in the hard X-ray band (10─30 keV), while a Type B QPO was more prominent in the soft X-ray band (1─10 keV). Further analysis reveals that the emergence of the Type C QPO suppresses the strength of the Type B QPO, particularly above 10 keV. Tracking the detailed evolution of these QPOs, we find that weakening of the Type B QPO coincides with strengthening of the Type C QPO, indicating a competitive interaction between them. These findings reveal a more complex relationship between Type B and Type C QPOs than previously recognized, suggesting they originate from distinct but interacting physical components within the accretion flow and/or jet, and provide new insights into the dynamics of accretion state transitions.

Keywords: X-ray transient sources
Deep Learning Improves Photometric Redshifts in All Regions of Color Space. Photometric redshifts (photo-z's) are crucial for the cosmology, galaxy evolution, and transient science drivers of next-generation imaging facilities like the Euclid Mission, the Vera C. Rubin Observatory, and the Nancy Grace Roman Space Telescope. Previous work has shown that image-based deep learning photo-z methods produce smaller scatter than photometry-based classical machine learning (ML) methods on the Sloan Digital Sky Survey (SDSS. Main Galaxy Sample, a test bed photo-z dataset. However, global assessments can obscure local trends. To explore this possibility, we used a self-organizing map (SOM) to cluster SDSS galaxies based on their ugriz colors. Deep learning methods achieve lower photo-z scatter than classical ML methods for all SOM cells. The fractional reduction in scatter is roughly constant across most of color space with the exception of the most bulge-dominated and reddest cells where it is smaller in magnitude. Interestingly, classical ML photo-z's suffer from a significant color-dependent attenuation bias, where photo-z's for galaxies within an SOM cell are systematically biased towards the cell's mean spectroscopic redshift and away from extreme values, which is not readily apparent when all objects are considered. In contrast, deep learning photo-z's suffer from very little color-dependent attenuation bias. The increased attenuation bias for classical ML photo-z methods is the primary reason why they exhibit larger scatter than deep learning methods. This difference can be explained by the deep learning methods weighting redshift information from the individual pixels of a galaxy image more optimally than integrated photometry.

Keywords: Galaxy distances, Regression, Astrostatistics techniques, Convolutional neural networks, Clustering
Polarization Angle Orthogonal Jumps in Fast Radio Bursts. Recently, polarization angle (PA) orthogonal jumps over millisecond timescales were discovered from three bursts of the repeating fast radio burst source FRB 20201124A by the FAST telescope. In general, PA jumps can arise from the coherent or incoherent superposition of two electromagnetic waves, with the total polarization fraction remaining constant in the former and not in the latter. The observations seem to be more consistent with incoherent superposition. The amplitudes of the two orthogonal modes are required to be comparable when jumps occur. We provide general constraints on FRB emission and propagation mechanisms based on the data. Physically, it is difficult to produce PA jumps through switching the dominance of the two orthogonal modes within millisecond timescales, and a geometric effect due to rotation of the source is more plausible. This requires that the emission region be within the magnetosphere of a spinning central engine, likely a magnetar. The two orthogonal modes in different directions can arise when the rotation of the source brings two independent emission regions with different dominant modes successively into the line of sight, due to either intrinsic radiation mechanisms or the O-mode undergoing a delayed transparency because of the Alfvén─O-mode conversion. Splitting of emission directions for the two modes due to plasma birefringence is not easy to achieve when the plasma is moving relativistically. For intrinsic radiation mechanisms, curvature radiation always predicts ∣EX/EO∣ ≳ 1, and it is difficult to produce jumps; whereas inverse Compton scattering can achieve the conversion amplitude ratio ∣EX/EO∣ = 1 to allow jumps to occur under special geometric configurations.

Keywords: Non-thermal radiation sources
Characterizing Supernova Host Galaxies with FrankenBlast: A Scalable Tool for Transient Host Galaxy Association, Photometry, and Stellar Population Modeling. We present FrankenBlast, a customized and improved version of the Blast web application. FrankenBlast associates transients to their host galaxies, performs host photometry, and runs a innovative spectral energy distribution fitting code to constrain host stellar population properties—all within minutes per object. We test FrankenBlast on 14,432 supernovae (SNe), ≍half of which are spectroscopically classified, and are able to constrain host properties for 9262 events. When contrasting the host stellar masses (M*), specific star formation rates (sSFR), and host dust extinction (AV) between spectroscopically and photometrically classified SNe Ia, Ib/c, II, and IIn, we determine that deviations in these distributions are primarily due to misclassified events contaminating the photometrically classified sample. We further show that the higher redshifts of the photometrically classified sample also force their M* and sSFR distributions to deviate from those of the spectroscopically classified sample, as these properties are redshift-dependent. We compare host properties between spectroscopically classified SN populations and determine if they primarily trace M* or SFR. We find that all SN populations seem to both depend on M* and SFR, with SNe II and IIn somewhat more SFR-dependent than SNe Ia and Ib/c, and SNe Ia more M*-dependent than all other classes. We find the difference in the SNe Ib/c and II hosts to be the most intriguing and speculate that SNe Ib/c must be more dependent on higher M* and more evolved environments for the right conditions for progenitor formation. All data products and FrankenBlast are publicly available, along with a developing FrankenBlast version intended for Rubin Observatory science products.

Keywords: Surveys, Stellar populations, Supernovae, Galaxies
Orbital Modulation Induced by a Third Component in the Overcontact Binary V0554 Dra. We present the first comprehensive photometric and spectroscopic analysis of the overcontact eclipsing binary V0554 Dra. By simultaneously modeling multiband light curves and radial velocity data using the Wilson─Devinney code, we determine that the system is a W-subtype contact binary with a mass ratio of 3.61 ± 0.01 and a shallow contact degree of 18% ± 2%. The light curves exhibit notable asymmetries near phase 0.5, which are well modeled by introducing a hot spot and a cool spot on the secondary component. The hot spot, located near the inner Lagrangian point, suggests the presence of mass transfer from the less massive primary to the more massive secondary. A detailed (O − C) analysis based on 3753 times of light minima reveals a long-term orbital period decrease at a rate of dP/dt = −4.22 × 10−7 days yr−1, superimposed with a 1.72 yr cyclic variation. Although mass is transferring from the less massive primary to the more massive secondary, which would typically lead to an increase in the orbital period under conservative conditions, the observed secular decrease suggests that angular momentum loss is the dominant driver of the system's evolution. Morphological analysis of the Transiting Exoplanet Survey Satellite light curves over a 5.4 yr baseline rules out magnetic activity as the cause of the cyclic variation, supporting the light-travel time effect (LTTE) due to a tertiary component. Assuming LTTE, we estimate the minimum mass of the third body to be 0.68 M⊙, with a projected separation of 2.15 au from the binary. Taken together, our findings strongly support the presence of a dynamically significant tertiary companion and reveal V0554 Dra as an exceptionally promising system for studying evolution induced by a third component and potential merger pathways in contact binaries.

Keywords: Eclipsing binary stars, Trinary stars, Contact binary stars
Blowing Star Formation Away in AGN Hosts (BAH). IV. Feeding and Feedback in 3C 293 Observed with JWST NIRSpec. We use JWST/NIRSpec observations of the radio galaxy 3C 293 to map the emission, extinction, and kinematics of hot molecular and ionized gas, as well as stellar kinematics, within the inner ∼2 kpc. The stellar velocity field is well described by a rotating disk model, with its kinematical center offset by  ∼0.″5  from the continuum peak. The hot molecular gas is traced by the H2 2.12 μm emission line and the ionized gas by [Fe II] 1.64 μm and Paα. The gas presents three main kinematic components: a rotating disk, seen as a narrow component (σ ∼ 100 km s−1); a blueshifted broad outflow (σ ∼ 250 km s−1); and a fast ionized outflow as a very broad component (σ ∼ 640 km s−1). Extinction maps reveal high AV values, up to ∼35, spatially coincident with dust lanes seen in optical images. In addition to the disk and outflow components, inflows along the dust lanes are detected in H2 gas, with a mass inflow rate of  Ṁin≃4×10−4M⊙yr−1 , which is lower than the active galactic nucleus (AGN) accretion rate. For the outflows, we derive peak mass outflow rates of 0.08 ± 0.02 M⊙ yr−1 (molecular) and 6.5 ± 1.7 M⊙ yr−1 (ionized). The outflow, driven by the radio jet, has a kinetic power of 5.7% of the jet power—enough to suppress star formation. Our results highlight 3C 293's turbulent postmerger history and JWST's unique capability for probing dust-obscured AGNs.

Keywords: James Webb Space Telescope, Active galaxies, Galaxy kinematics, Radio galaxies
Impact of 3D Macrophysics and Nuclear Physics on the p-nuclei in O─C Shell Mergers. O─C shell mergers in massive stars are a site for producing the p-nuclei by the γ process, but 1D stellar models rely on mixing length theory (MLT), which does not match the radial velocity profiles of 3D hydrodynamic simulations. We investigate how 3D macrophysics-informed mixing impacts the nucleosynthesis of p-nuclei. We postprocess the O shell of the MZAMS = 15 M⊙, Z = 0.02 model from the NuGrid stellar data set. Applying a downturn to velocities at the boundary and increasing velocities across the shell as obtained in previous results, we find a nonlinear, nonmonotonic increase in p-nuclei production with a spread of 0.96 dex and find that isotopic ratios can change. Reducing C-shell ingestion rates as found in 3D simulations suppresses production, with spreads of 1.22─1.84 dex across MLT and downturn scenarios. Applying dips to the diffusion profile to mimic quenching events also suppresses production, with a 0.51 dex spread. We analyze the impact of varying all photodisintegration rates of unstable n-deficient isotopes from Se to Po by a factor of 10 up and down. The nuclear physics variations for the MLT and downturn cases have a spread of 0.56─0.78 dex. We also provide which reaction rates are correlated with the p-nuclei and find few correlations shared between mixing scenarios. Our results demonstrate that uncertainties in mixing arising from uncertain 3D macrophysics are as significant as nuclear physics and are crucial for understanding p-nuclei production during O─C shell mergers quantitatively.

Keywords: Massive stars, P-process, Nuclear astrophysics, Stellar convective shells, Oxygen burning