Sazuna/UAT_keywords huggingface dataset:
Tracing Quenching in Nearby Galaxies through Inner Surface Mass Density and Cold Gas Content. The inner stellar mass surface density within 1 kpc, Σ1, has emerged as a suitable proxy for bulge growth and galaxy quenching. However, the dependence of cold gas content on Σ1 has not been thoroughly explored. In this paper, we examine the relationship between Σ1, as well as the mass-relative parameter ∆Σ1, and the atomic (fHI) and molecular (fH2) cold gas fractions in massive, nearby galaxies. We utilize a sample of 341 galaxies with HI data and 201 galaxies with H2 data from the xGASS and xCOLDGASS surveys, spanning 0.02 ≤ z ≤ 0.05 and a stellar mass range of 1010 ≤ M*/M⊙ ≤ 1011.5. While we observe that a decline in both fHI and fH2 is associated with increasing Σ1, we find that fH2 shows a sharper decline above a threshold value of ∆Σ1 = 0. In addition, the fraction of galaxies with active galactic nucleus (AGN) activity (Seyferts and LINERs) increases with ∆Σ1, with the greatest increase occurring between 0 ≲ ∆Σ1 ≲ 0.2 dex. We propose an evolutionary track in the plane of fH2 − ∆Σ1, whereby molecular gas depletion at fixed mass coincides with a rise in AGN activity. Our results suggest that central bulge growth is more tightly coupled to the depletion of molecular gas rather than atomic gas, with AGN feedback possibly contributing to this process. Our work highlights the utility of Σ1 and ∆Σ1 as tracers of quenching in massive galaxies.

Keywords: Molecular gas, Galaxy structure, Interstellar atomic gas
Uncertainty in Hadronic Diffuse γ-Ray Emission from the Temporal Stochasticity of Cosmic-Ray Sources. Diffuse γ-ray emission is a key probe of cosmic-ray (CR) distribution within the Galaxy. However, the discrepancies between observations and theoretical model expectations highlight the need for refined uncertainty estimates. In the literature, spatial and temporal variability of lepton flux has been discussed as an uncertainty in diffuse γ-ray estimation. In the present work, we demonstrate that variability in the high-energy CR hadron flux is an important, yet previously underappreciated, source of uncertainty in diffuse γ-ray estimates. To assess this effect, we perform fully three-dimensional, time-dependent GALPROP simulations of CR protons injected from discrete Galactic sources. Our results reveal that the uncertainty in the hadronic component of diffuse γ rays is nonnegligible and can be comparable to, or even exceed, current experimental uncertainties at very high energies. This finding challenges the conventional assumption that only leptonic fluctuations are relevant to diffuse γ-ray modeling.

Keywords: High energy astrophysics, Galactic cosmic rays, Cosmic ray sources, Gamma-rays, Cosmic rays
Correlated Quasiperiodic Pulsations in Type III Radio Bursts and Solar EUV Emission, Jetlets and Magnetic Fields: Comparisons of Intervals with and without Type III Storms. Solar p-modes are ∼5 minute acoustic waves, which can be used as helioseismological diagnostics of the Sun's subsurface. Recent studies relate them to quasiperiodic pulsations (QPPs) identified in X-rays, radio waves, and extreme ultraviolet (EUV) emission. QPPs with ∼5 minute periods have been simultaneously observed in Solar Dynamics Observatory (SDO) EUV measurements and Parker Solar Probe (PSP) observations of Type III radio storms, suggesting a link between p-modes and electron acceleration. Using examples when potential field source surface mapping indicated that PSP and SDO were magnetically connected, we compared periodicities in intervals with ("loud") or without ("quiet") coincident Type III radio storms, and looked for small jets (jetlets), as indicators of open field lines enabling electrons to escape and produce radio waves. QPPs of 3─10 minutes occurred in EUV and Helioseismic and Magnetic Imager (HMI) data in all intervals. Whereas the p-mode amplitudes in photospheric EUV and HMI data were similar in "quiet" and "loud" events, amplitudes in coronal EUV waves were approximately an order of magnitude larger during "loud" intervals. The jetlet rate was comparably higher during "loud" times, consistent with the low corona as the source of electron beams producing Type III waves. The larger EUV amplitudes and higher jetlet rates during "loud" intervals indicate that the presence of electron acceleration along open field lines depends strongly on QPP magnitude and the associated magnetic field configuration. These findings provide new insights into the conditions under which p-mode energy can leak from the photosphere into the corona.

Keywords: Solar oscillations, Solar radio emission, Helioseismic pulsations
CHIME/FRB Discovery of the Extremely Active Fast Radio Burst Source FRB 20240114A. Among the thousands of observed fast radio bursts (FRBs), a few sources exhibit exceptionally high burst activity observable by many telescopes across a broad range of radio frequencies. Almost all of these highly active repeaters have been discovered by the Canadian Hydrogen Intensity Mapping Experiment/FRB project (CHIME/FRB), due to its daily observations of the entire northern sky as a transit radio telescope. FRB 20240114A is a source discovered and reported by CHIME/FRB to the community in 2024 January; given its low declination, even the detection of a few bursts hints at a high burst rate. Following the community announcement of this source as a potentially active repeater, it was extensively followed up by other observatories and has emerged as one of the most prolific FRB repeaters ever observed. This paper presents the five bursts CHIME/FRB observed from FRB 20240114A, with channelized raw voltage data saved for two bursts. We do not observe changes in the dispersion measure of the source greater than ∼1.3 pc cm−3 in our observations over a nearly 1 yr baseline. We find a rotation measure of ∼+320 rad m−2. We do not find evidence for scattering at the level of &lt;0.3 ms in the bursts, and we find no evidence for astrophysical scintillation. In our observations of FRB 20240114A, we see a burst rate ∼49 times higher than the median upper limit on the burst rate of apparent nonrepeaters also discovered by CHIME/FRB. With many thousands of bursts observed to date, FRB 20240114A has given the field an extraordinary opportunity to extensively study an FRB and understand its origins.

Keywords: Radio bursts, Radio transient sources
Carbonaceous Cosmic Dust Analogs Distinguish between Ion Bombardment and Temperature. Carbonaceous cosmic dust is formed in the circumstellar envelopes of asymptotic giant branch stars and supernovae ejecta. Reprocessed carbonaceous cosmic dust, abundant in the light elements C, H, O, and N is found in asteroids and comets. These elements form dust that is well described as an amorphous, covalently bonded network solid with a structure that is expected to reflect the key formative influences of ion bombardment, temperature modification, and UV irradiation. Ion bombardment of a dust grain by an energetic particle in a stellar wind creates a nonequilibrium thermal spike event, which contrasts with the close-to-equilibrium process of annealing under the local ambient conditions. There is a gap in our knowledge of how to distinguish ion bombardment as a synthesis process from postsynthesis thermal modification through infrared spectroscopy. Here we synthesize dust from molecular precursors under a range of controlled space-like conditions to form a database of IR spectra. We apply principal component analysis to show that the first principal component correlates with ion bombardment intensity during synthesis and the second principal component correlates with annealing temperature. The spectral loading curves of these two principal components are proposed as potential diagnostic tools to uncover past formative influences on cosmic dust as well as on the carbonaceous content of asteroids such as Bennu and Ryugu. Amorphous organic networks composed of the CHON elements unify previous ideas on cosmic dust by encompassing features of PAHs, tholins, and mixed aliphatic─aromatic nanoparticles.

Keywords: Dust composition, Polycyclic aromatic hydrocarbons, Infrared spectroscopy, Plasma physics, Carbonaceous chondrites, Laboratory astrophysics, Interstellar plasma, Principal component analysis, Astrophysical dust processes, Carbonaceous grains, Interstellar dust processes, Pre-biotic astrochemistry
How DREAMS Are Made: Emulating Satellite Galaxy and Subhalo Populations with Diffusion Models and Point Clouds. The connection between galaxies and their host dark matter (DM) halos is critical to our understanding of cosmology, galaxy formation, and DM physics. To maximize the return of upcoming cosmological surveys, we need an accurate way to model this complex relationship. Many techniques have been developed to model this connection, from halo occupation distribution (HOD) to empirical and semianalytic models to hydrodynamics. Hydrodynamic simulations can incorporate more detailed astrophysical processes but are computationally expensive; HODs, on the other hand, are computationally cheap but have limited accuracy. In this work, we present NeHOD, a generative framework based on the variational diffusion model and transformer, for painting galaxies/subhalos on top of DM with an accuracy of hydrodynamic simulations but at a computational cost similar to HOD. By modeling galaxies/subhalos as point clouds, instead of binning or voxelization, we can resolve small spatial scales down to the resolution of the simulations. For each halo, NeHOD predicts the positions, velocities, masses, and concentrations of its central and satellite galaxies. We train NeHOD on the TNG-warm DM suite of the DREAMS project, which consists of 1024 high-resolution zoom-in hydrodynamic simulations of Milky Way-mass halos with varying warm DM mass and astrophysical parameters. We show that our model captures the complex relationships between subhalo properties as a function of the simulation parameters, including the mass functions, stellar─halo mass relations, concentration─mass relations, and spatial clustering. Our method can be used for a large variety of downstream applications, from galaxy clustering to strong-lensing studies.

Keywords: Warm dark matter, Galaxies
Revealing the Connection between the Filamentary Hierarchy and Star Cluster Formation in a Simulated NGC 628 Galaxy. There is abundant observational evidence for the hierarchical, interconnected nature of filaments in the interstellar medium extending from galactic down to subparsec scales. New JWST images of NGC 628, in particular, show clusters forming along the two spiral arms of this galaxy. In this paper, we investigate filament and cluster properties in an NGC 628-like multiscale high-resolution magnetohydrodynamic simulation. We use a filament finding tool to identify filaments and derive the probability density functions (PDFs) for the filament lengths and masses. Using a clustering algorithm, we identify star clusters formed between 268 and 278 Myr and follow this population as the galaxy evolves for 60 Myr, calculating their mass PDFs, average radius growth rate, and average mass loss rate. We find a power-law index of αm = −1.35 for the filament masses. Calculating the power-law index from our cluster mass PDF, we find a value of αc,m = −1.35 when the clusters first form, exactly our filament mass power-law index. This shows that properties of young clusters arise from the gravitational fragmentation of their host filaments. We track the postformation evolution of the clusters as they become unbound, increase in radius, and decrease in mass, yielding an ever steeper mass power-law index. After 60 Myr, the mass power-law index is αc,m = −1.55, matching other simulations and observations.

Keywords: Interstellar filaments, Spiral galaxies, Magnetohydrodynamical simulations, Star forming regions, Star formation, Interstellar medium, Star clusters
GRB 171205A/SN 2017iuk: Is the Central Engine a Magnetar?. It is known that there is an association between long gamma-ray bursts and supernovae (SNe), and study of these SNe is important for exploring the death of massive stars. Here, we investigate GRB 171205A/SN 2017iuk (at redshift z = 0.0368) by fitting multiband light curves and modeling the SN 2017iuk spectra with SYNAPPS. The light curve of GRB 171205A/SN 2017iuk shows a long plateau, not only in X-rays but also in optical bands. This plateau may be from the late-time contribution of a magnetar central engine. We use a magnetar spindown model, 56Ni model, and cooling model to fit the multiband light curves. The best-fitting results reveal the total SN ejected mass  Mej=4.60−0.70+1.20M⊙ , Ni mass  MNi=0.31−0.03+0.05M⊙ , and total kinetic energy EK ≍ 3.14 × 1052 erg, consistent with the average values inferred for other gamma-ray burst-SNe. The best-fitting photospheric velocities are 14,700 and 11,400 km s−1, and the photospheric temperatures are 9900 and 11,800 K, at +7.2 and +13.2 days (respectively). From our light curves and spectral analysis, we suggest that the central engine of GRB 171205A/SN 2017iuk is likely to be a magnetar, with initial spin period  P0=70.61−0.97+0.62ms  and surface magnetic field at the pole  Bp=3.84−0.61+0.33×1015G .

Keywords: Gamma-ray bursts, Supernovae
Unified Spectrospatial Forward Models: Spatially Continuous Maps of Weak Emission Lines in the Rosette Nebula with SDSS-V LVM. Analyses of integral field unit data are typically performed on a per-spaxel basis, with each spectrum modelled independently. For low signal-to-noise ratio (S/N) features such as weak emission lines, estimating properties is difficult and imprecise. Arbitrary binning schemes boost S/N at the cost of resolution, and risk introducing biases. We present a general forward-modeling approach that assumes spectra close on the sky are more similar than distant ones, and so can be modelled jointly. These "spectrospatial" models exploit spatial correlation to provide robust inferences, while simultaneously providing continuous predictions of line properties like strength and kinematics across the sky. Instrumental and calibration systematics are straightforward to include and infer. The model provides a natural trade-off between spatial resolution and S/N in a data-driven way. We apply this to Sloan Digital Sky Survey V Local Volume Mapper (LVM) data of the Rosette Nebula, producing continuous maps of fluxes and kinematics for Balmer, nebular, and auroral lines, as well as weak C II and N II recombination lines, demonstrating the approach across 3 orders of magnitude in S/N, including in the very low-S/N regime. The method recovers identical morphologies across different lines tracing similar ionisation volumes, at varying resolutions set by the S/N. We additionally provide a general framework for building and fitting such models in JAX, suitable for many applications. The implementation is fast and memory efficient, scales to large data volumes as in LVM, and can be deployed on hardware accelerators.

Keywords: Astronomy data modeling, Astrostatistics, Interstellar medium, Spectroscopy, H II regions
The ALMA-QUARKS Survey: Hot Molecular Cores Are a Long-standing Phenomenon in the Evolution of Massive Protostars. We present an analysis of the QUARKS survey sample, focusing on protoclusters where hot molecular cores (HMCs; traced by CH3CN (12─11)) and HC/UC H II regions (traced by H30α/H40α) coexist. Using the high-resolution, high-sensitivity 1.3 mm data from the QUARKS survey, we identify 125 hot molecular fragments (HMFs), which represent the substructures of HMCs at higher resolution. From line integrated intensity maps of CH3CN (123─113) and H30α, we resolve the spatial distribution of HMFs and HC/UC H II regions. By combining with observations of 12CO (2─1) outflows and 1.3 mm continuum, we classify HMFs into four types: HMFs associated with jetlike outflow, wide-angle outflow, and nondetectable outflow and shell-like HMFs near HC/UC H II regions. This diversity possibly indicates that the hot core could be a polymorphic and long-standing phenomenon in the evolution of massive protostars. The separation between HMFs and H30α/H40α emission suggests that sequential high-mass star formation within young protoclusters is not likely related to feedback mechanisms.

Keywords: Protostars, Star forming regions, Star formation
The Nature of the Ultrahigh-energy Source 1LHAASO J1740+0948u and Its Connection to PSR J1740+1000. We present a multiwavelength analysis of 1LHAASO J1740+0948u and its surroundings including the pulsar wind nebula of middle-aged pulsar PSR J1740+1000. Although a dozen X-ray sources are found within the ultrahigh-energy (UHE) emission site, careful analysis shows that they are unlikely to produce the observed UHE emission. The most likely particle accelerator is PSR J1740+1000, which if offset by 13 '  north of the UHE source but appears to be connected to it by an extended feature seen in X-rays. For a plausible pulsar distance of 1.2 kpc, 1LHAASO J1740+0948u must be located about 5 pc away, which requires rapid transport of electrons along the feature to avoid radiative losses. This poses several challenges for standard pulsar theory. First, being produced ≲10 kyr ago, particles must have been accelerated to the energy corresponding to a large fraction of the pulsar's full potential drop across the polar cap. Second, due to the lack of TeV emission extension toward the pulsar, particles must be accumulating in the UHE region. In this context, we discuss two possible scenarios: a tail filled with pulsar wind and confined by the bow shock due to the fast pulsar's motion and an interstellar medium filament filled by the most energetic pulsar wind particles escaping from the apex of the bow shock.

Keywords: X-ray astronomy, Rotation powered pulsars, Classification, Gamma-ray sources, Pulsars, Pulsar wind nebulae
Implications of Nonequatorial Relativistic Accretion Flows for Ultrafast Inflows in Active Galactic Nuclei. Motivated by a number of X-ray observations of active galactic nuclei (AGNs) that exhibit a potential signature of ultrafast inflows (UFIs), we consider in this work a scenario that UFIs can be physically identified as weakly magnetized hydrodynamic accretion flows that are guided and channeled by a poloidal magnetic field into low-to-mid-latitude above the equatorial disk. In the context of general relativistic hydrodynamics (GRHD) under a weak-field limit in Kerr spacetime, we present a set of preliminary results by numerically calculating the physical property of GRHD flows (e.g., kinematics and density distribution) in an effort to simulate redshifted absorption line spectra. Our model demonstrates that such GRHD accretion off the equatorial plane (i.e., v ≳ 0.1 c where c is the speed of light in the vicinity of AGN closer than ∼100 Schwarzschild radii) can manifest itself as UFIs in the form of a redshifted absorption signature assuming the observed characteristics such as column density of NH ∼ 1023 cm−2 and ionization parameter of  log(ξ[ergcms−1])∼3 , as also seen in recent multiepoch NuSTAR observations among other data.

Keywords: Accretion, Black hole physics, High resolution spectroscopy, Photoionization, Seyfert galaxies, X-ray active galactic nuclei, General relativity, Ionization
Structural Tilting and Depth-dependent Behavior of Equatorial Rossby Waves. Over the past decade, solar equatorial Rossby waves have been unambiguously identified and are considered potential diagnostics of solar interior dynamics. We investigate their inclined structure and temporal evolution in the solar interior across multiple depths using approximately 14.5 yr of ring-diagram and time─distance helioseismology data from Solar Dynamics Observatory/Helioseismic and Magnetic Imager. Normalized phase differences and cross power are computed from filtered spherical harmonic coefficients of radial vorticity to probe the structural tilt and power of Rossby waves. We find a systematic and robust depth-dependent phase behavior that shows no clear significant correlation with the solar cycle, while the depth-dependent cross power exhibits a positive correlation with the solar cycle for both data sets. Our results show that deeper depths lead in phase over shallower ones, with increasing negative phases with depth. We infer that Rossby waves exhibit a retrograde tilt relative to the Sun's rotation that is stable throughout the solar cycle. Analogous small tilts have been noted in planetary atmospheres and in magnetohydrodynamic simulations of the Sun, indicating that this behavior is not uncommon in rotating, stratified bodies and has implications for angular momentum and energy transport in the solar interior.

Keywords: Helioseismology, Solar physics, Solar oscillations, Solar interior
Interaction of Four Homologous Coronal Mass Ejections near the Sun. Interaction between two coronal mass ejections (CMEs) affects their kinematics, morphology, space-weather effects, etc. For the first time, we report the interaction of four homologous CMEs in the field of view of Large Angle and Spectrometric Coronagraph (LASCO) on board Solar and Heliospheric Observatory (SOHO). A new active region (NOAA 11303) started to emerge on 2011 September 23 and developed quickly in the first 2 days. Subsequently, four CMEs (labeled as CME1, CME2, CME3, and CME4 sequentially) from this active region were recorded by LASCO/C2 in 10 hr on September 25. Interestingly, CME2 (677 km s−1) and CME4 (921 km s−1) are faster and catch up with CME1 (502 km s−1) and CME3 (516 km s−1) at ∼4.6 and ∼5.0 R⊙, respectively. Both CME1 and CME3 are compressed obviously, while the morphology of CME2 and CME4 does not show substantial changes. The aspect ratio of CME3 increases from ∼1.1 to ∼3.2 in 3 hr, indicating that the magnetic field strength inside CME3 increases by a factor of 3 quickly due to the interaction. Very interestingly, CME3 would normally be unable to catch up with CME2. However, the prior interactions accelerated CME3 and decelerated CME2. As a result, the composite of CME3 and CME4 moves faster (624 km s−1) and catches up with the composite of CME1 and CME2 (492 km s−1) at ∼14.3 R⊙. The four separately erupted homologous CMEs eventually combined and formed a large composite near the Sun, which can potentially cause intense geomagnetic storms if it reaches the Earth.

Keywords: Solar activity, Solar active regions, Solar coronal mass ejections
Equation versus AI: Predicting Density and Measuring Width of Molecular Clouds by Multiscale Decomposition. The interstellar medium is ubiquitous throughout the universe across multiple scales. In this study, we introduce the multiscale decomposition reconstruction method, an equation-based model designed to derive width maps of interstellar medium structures and predict their volume density distribution on the plane of the sky from input column density data. This approach applies the constrained diffusion algorithm, based on a simple yet common physical picture: as molecular clouds evolve to form stars, the density of the interstellar medium increases while the scale decreases. Validation on simulations confirms that this method accurately predicts volume density with minimal error. Notably, the equation-based model performs comparably to or even more accurately than the AI-based denoising diffusion probabilistic models that rely on vast parameters and substantial computational resources. Unlike the "black-box" nature of AI, our equation-based model offers full transparency, making it easier to interpret, debug, and validate. The simplicity, interpretability, and computational efficiency make it powerful not only for understanding complex astrophysical phenomena but also for complementing and enhancing AI-based methods.

Keywords: Computational methods, Astrobiology, Star formation, Interstellar medium, Astronomical methods