Sazuna/UAT_keywords huggingface dataset:
Evidence of 5 minute Oscillations from Parker Solar Probe. The Sun's surface vibrates in characteristic 5 minute oscillations, known as p-modes, generated by sound waves trapped within the convection zone. Although these oscillations have long been hypothesized to reach into the solar wind, direct in situ evidence has remained elusive, even during previous close encounters by Parker Solar Probe (PSP). Here, we present strong in situ evidence of 5 minute oscillations in the upper solar corona, based on observations from PSP's three closest perihelia. In two events at 9.9 solar radii (R⊙), we identify statistically significant (∼6σ) 3.1─3.2 mHz peaks in the magnetic field power spectrum, each appearing as a large-amplitude, spherically polarized Alfvénic wave train lasting approximately 35 minutes. These results demonstrate that global solar oscillations can reach the solar wind.

Keywords: Fast solar wind, Helioseismology, Interplanetary turbulence, Solar wind, Solar corona, Solar coronal holes
Revealing the Unseen: The Discovery of Long-awaited Radiation from the Intermittent Pulsar PSR B1931+24. Pulsars are typically characterized by their stable, highly magnetized, and fast-rotating nature, which underpins their persistent radio emissions. However, the discovery of prolonged radio-quiet ("off") states in intermittent pulsars, such as PSR B1931+24, has been challenging the fundamental theory of pulsar magnetospheric emission. Despite long-term monitoring with several telescopes over 20 yr, the observations of PSR B1931+24 had not detected any significant emission during its "off" states. Recently, sensitive observations via the Five-hundred-meter Aperture Spherical radio Telescope revealed the mysterious weak emissions containing occasional faint bursting pulses during the "off" states of PSR B1931+24, signifying the theory of pulsar magnetospheric emission that the pulsar cannot remain off for long unless it truly dies. Along with a substantial decrease in flux density, a contraction and change in the integrated pulse profile are measured in the "off" state compared to the radio-loud ("on") state, indicating alterations in the plasma supply and magnetospheric structure. Additionally, previously unobserved asynchronous, nonuniform emission patterns are found in both states, implying a spatially inhomogeneous pair-cascade associated with the coherent radio emission of the pulsar. Furthermore, statistical comparisons between the faint off-state bursts and the on-state emission show that the faint bursts cannot be explained simply as a scaled-down version of the on-state emission. Instead, they constitute a distinct emission mode, plausibly linked to changes in plasma supply and the magnetospheric configuration of PSR B1931+24. These findings greatly advance our understanding of pulsar magnetospheric dynamics and emission mechanisms.

Keywords: Neutron stars, Radio pulsars
A Morphology Catalog of Galaxies in CEERS: Evolution in the Size and Color Gradients of Galaxies Since Cosmic Dawn. We present measurements of morphological parameters from fitting 53,885 galaxies detected to a magnitude limit of F356W &lt; 28.5 in the CEERS NIRCam imaging with GALFIT in six broadband filters: F115W, F150W, F200W, F277W, F356W, and F444W. We provide a public catalog of Sérsic indices, effective semimajor axes, axis ratios, integrated magnitudes, and position angles for these galaxies in each of the filters. Uncertainties in the measured parameters are estimated from simulated galaxies that have similar noise and background properties as the observed galaxies. We compare our measurements with those in the CANDELS/Extended Groth Strip field measured with Hubble Space Telescope/WFC3 and find that the sizes agree to within 0.09 dex and the Sérsic indices agree to within 0.13 dex. We further present the evolution in the size─mass relation, and find that the evolution to z ∼ 9 is consistent with previous results derived at lower redshift. Finally, we look at the color gradients of galaxies at 1 &lt; z &lt; 5 and find that for late-type galaxies (n &lt; 2.5), there is a strong dependence on mass, but no apparent evolution with redshift, indicating that the stellar populations and dust attenuation in more massive galaxies vary substantially with radius and contribute to significant morphological k-corrections. For early-type galaxies (n &gt; 2.5), the color gradients are nearly flat with no dependence on mass, indicating that the stellar populations are more uniform throughout. The structural measurements presented are accurate to 20% or better for most galaxies with F356W &lt; 27.0 mag and will enable further studies of galaxy morphology to z ∼ 10.

Keywords: Galaxy classification systems, Galaxies
JWST Observations of Starbursts: Polycyclic Aromatic Hydrocarbons Closely Trace the Cool Phase of M82's Galactic Wind. Stellar feedback drives multiphase gas outflows from starburst galaxies, but the interpretation of dust emission in these winds remains uncertain. To investigate this, we analyze new JWST mid-infrared images tracing polycyclic aromatic hydrocarbon (PAH) emission at 7.7 and 11.3 μm from the outflow of the prototypical starburst M82 out to 3.2 kpc. We find that PAH emission shows significant correlations with CO, Hα, and X-ray emission within the outflow, though the strengths and behaviors of these correlations vary with gas phase and distance from the starburst. PAH emission correlates strongly with cold molecular gas, with PAH─CO scaling relations in the wind nearly identical to those in galaxy disks despite the very different conditions. The Hα─PAH correlation indicates that Hα traces the surfaces of PAH-bearing clouds, consistent with arising from ionized layers produced by shocks. Meanwhile, the PAH─X-ray correlation disappears once distance effects are controlled for past 2 kpc, suggesting that PAHs are decoupled from the hot gas and the global correlation merely reflects the large-scale structure of the outflow. The PAH-to-neutral gas ratio remains nearly flat to 2 kpc, with variations following changes in the radiation field. This implies that the product of PAH abundance and dust-to-gas ratio does not change significantly over the inner portion of the outflow. Together, these results demonstrate that PAHs robustly trace the cold phase of M82's wind, surviving well beyond the starburst and providing a powerful, high-resolution proxy for mapping the life cycle of entrained cold material in galactic outflows.

Keywords: Galactic winds, Dust composition, Molecular gas, Starburst galaxies
No Observational Evidence for Dark Matter Nor a Large Metallicity Spread in the Extreme Milky Way Satellite Ursa Major III/UNIONS 1. The extremely low-luminosity, compact Milky Way satellite Ursa Major III/UNIONS 1 (UMaIII/U1; LV = 11 L⊙, a1/2 = 3 pc) was found to have a substantial velocity dispersion at the time of its discovery ( σv=3.7−1.0+1.4kms−1 ), suggesting that it might be an exceptional, highly dark-matter-dominated dwarf galaxy with very few stars. However, significant questions remained about the system's dark matter content and nature as a dwarf galaxy, due to the small member sample (N = 11), possible spectroscopic binaries, and the lack of any metallicity information. Here, we present new spectroscopic observations covering N = 16 members that both dynamically and chemically test the true nature of UMaIII/U1. From higher-precision Keck/DEIMOS spectra, we find a 95% confidence level velocity dispersion limit of σv &lt; 2.3 km s−1, with a ∼120:1 likelihood ratio favoring the expected stellar-only dispersion of σ* ≍ 0.1 km s−1 over the original 3.7 km s−1 dispersion. There is now no observational evidence for dark matter in the system. From Keck/LRIS spectra targeting the Ca II K line, we also measure the first metallicities for 12 member stars, finding a mean metallicity of [Fe/H] = − 2.65 ± 0.1 (stat.) ±0.3 (zero-point), with a metallicity dispersion limit of σ[Fe/H] &lt; 0.35 dex (at the 95% credible level). Together, these properties are more consistent with UMaIII/U1 being a star cluster, though the dwarf galaxy scenario is not fully ruled out. Under this interpretation, UMaIII/U1 ranks among the faintest and most metal-poor star clusters yet discovered.

Keywords: Stellar kinematics, Dwarf galaxies, Dark matter, Milky Way Galaxy, Star clusters
The Astrometric Resoeccentric Degeneracy: Eccentric Single Planets Mimic 2:1 Resonant Planet Pairs in Astrometry. Detections of long-period giant exoplanets will expand dramatically with Gaia Data Release 4, but interpreting these signals will require care. We derive the astrometric resoeccentric degeneracy: an astrometric analogue of the well-known radial velocity degeneracy in which a single eccentric planet can mimic two circular planets near a 2:1 period ratio. To first order in eccentricity, the sky-projected motion of a single eccentric orbit decomposes into a fundamental mode and first harmonic with an amplitude proportional to that eccentricity. A pair of coplanar, circular planets in a 2:1 orbital resonance produces the same harmonic structure: the outer planet sets the fundamental mode, while the inner planet supplies an apparent first harmonic. We present a mapping between the harmonic amplitudes and effective eccentricity (eeff) of a single planet that mimics a 2:1 configuration, demonstrating that eeff = 21/3(Mp,2/Mp,1), the masses of the inner and outer planets, respectively. Using simulated Gaia data, we show that (1) coplanar 2:1 systems are statistically indistinguishable from a single eccentric planet and (2) mutual inclination can break this degeneracy. This bias favors detecting mutually inclined systems, often fingerprints of a dynamically hot history—traces for processes such as planet─planet scattering or secular chaos. Determining the planetary architectures in which this degeneracy holds will be essential for measuring cool-giant occurrence rates with Gaia and for inferring their dynamical evolution histories.

Keywords: Exoplanet dynamics, Exoplanet systems, Astrometry, Exoplanet detection methods, Gaia
Probing Binary Black Hole Formation Channels through Cosmic Large-scale Structure. The growing number of binary black hole mergers detected through gravitational waves offers unprecedented insight into their underlying population, yet their astrophysical formation channels remain unresolved. We present a new method to distinguish binary black hole formation channels using their spatial clustering at cosmological scales. Employing the cosmological hydrodynamic simulation Illustris, we trace the distribution of mergers across cosmic time and compare them with the underlying matter distribution associated with three candidate origins: isolated binary stellar evolution, binaries embedded in active galactic nucleus (AGN) disks, and primordial black holes within dark matter halos. Using mock catalogs for next-generation facilities such as Cosmic Explorer, we find that their sensitivities could enable differentiation of these formation pathways out to redshift z ∼ 5 within the first decade of observations. This approach provides a new framework to link gravitational-wave populations with the large-scale structure of the Universe. By treating black hole mergers as cosmological tracers, our results demonstrate how cross-correlations between gravitational-wave catalogs and the cosmic matter field can constrain the relative contribution of stellar, AGN, and primordial channels, offering a complementary probe to population inference studies. These findings underscore the emerging potential of gravitational-wave cosmology to reveal where and how black holes form and merge across cosmic history.

Keywords: Hydrodynamical simulations, Black holes, Large-scale structure of the universe, Gravitational wave astronomy, Gravitational waves
Probing Heavily Obscured Active Galactic Nuclei in Major Galaxy Mergers Using the Millimeter─X-Ray Correlation. The study of heavily obscured supermassive black hole (SMBH) growth in late-stage galaxy mergers is challenging: column densities NH &gt; 1024 cm−2 can block most nuclear emission, leaving significant gaps in the SMBH growth census. Millimeter-wave continuum emission offers a potential window into this obscured phase, as it can trace active galactic nuclei (AGN) activity through mechanisms less affected by dust extinction. In this work, we test whether the observed correlation between millimeter (∼200 GHz) and hard X-ray (14─150 keV) luminosities can be used to plausibly identify hidden AGN in local ultraluminous infrared galaxies, including systems hosting confirmed dual AGN. We identify three sources—one confirmed AGN and two strong candidates—presenting significant evidence of AGN activity. The confirmed dual AGN lie within ∼3σ of the millimeter─X-ray correlation, suggesting this relation can be used to identify hidden pairs. By combining the position of each source relative to this correlation with independent star formation rate constraints, we propose a method to disentangle AGN and star formation contributions for sources with measured column densities. While our analysis is based on a small, heterogeneous local sample and relies on empirical scaling relations, these results indicate that millimeter continuum emission may provide a useful complementary diagnostic for obscured SMBH growth. Atacama Large Millimeter/submillimeter Array observations at high angular resolutions are particularly valuable for this approach, while future facilities such as the ngVLA will be essential to test its robustness in larger and more distant samples.

Keywords: AGN host galaxies, Supermassive black holes, Active galactic nuclei, Millimeter astronomy
Preperihelion Volatile Evolution of Interstellar Comet 3I/ATLAS Indicating Significant Contribution from an Extended Source in the Coma. Interstellar comets provide rare opportunities for probing the diversity of refractory and volatile inventory around other stars. As the second ever interstellar comet and the third interstellar object, 3I/ATLAS has been the focus of telescopic observations since its discovery in 2025 July. Following the previous observations at multiwavelengths, we present further radio observations of the 1665/1667 MHz ground-state OH lines and millimeter observations of the CO(J = 1─0) transition at 115.271 GHz that trace the coma H2O and CO abundances, respectively. We derived OH production rates of (1.32 ± 0.47) × 1028 s−1 at 2.27 au and (1.89 ± 0.37) × 1028 s−1 at 1.96 au, as well as an average CO production rate of (5.75 ± 1.91) × 1027 s−1 between 2.33 and 1.75 au, inferring a CO/H2O ratio of (28% ± 11%). With the mean HCN production rate of 2.5 × 1025 s−1 at 2.1 au reported by N. X. Roth et al. and I. M. Coulson et al., we infer a CO/HCN ratio of (230 ± 76). By synthesizing water production rates measured with instruments of different apertures, we found that the sublimation from an extended source in the coma contributes significantly to 3I's preperihelion water measurements, accounting for up to 80% from 3 to 2 au.

Keywords: Small Solar System bodies, Comets, Radio astrometry, Interstellar objects
The Cosmic-Ray Knee as a Local Signature of Nearby PeVatrons. A "knee" in the cosmic-ray spectrum, characterized by a sudden steepening of the spectral shape at ∼4 PeV, may be interpreted either as a global feature of Galactic cosmic rays or as a local signature. In the former scenario, cosmic-ray spectra throughout the Galaxy would be similar to that observed in the solar neighborhood, and the knee would be a common feature of the cosmic-ray sea. In the latter scenario, the PeV cosmic-ray flux varies across the Galactic disk, and the knee is dominantly contributed by a small number of nearby sources. By simulating cosmic-ray propagation in the Galactic magnetic field and interstellar medium, we show that the two scenarios correspond to different regimes of the birth rate of PeV proton accelerators and depend on the presence of powerful nearby sources. By comparison with both cosmic-ray and gamma-ray observations, we find that a local knee would be best explained by sources located at distances of order ∼1 kpc and with ages in the range 0.1─1 Myr, with the Cygnus Cocoon being a particularly promising candidate.

Keywords: Galactic cosmic rays, Gamma-ray sources
Upper Limit on HF(1─0) Absorption in a Dusty Star-forming Galaxy at z = 6: Constraints on Early Fluorine Enrichment. Wolf─Rayet (WR) stars have recently attracted attention as possible drivers of early chemical enrichment, including the production of fluorine, whose nucleosynthetic origin remains debated. To test the contribution of massive stars to fluorine production in the early Universe, we conducted Atacama Large Millimeter/submillimeter Array Band 5 spectroscopy of the HF(1─0) absorption line toward a dusty star-forming galaxy at z = 6.024. This galaxy has a known gas-phase metallicity and is too young for low-mass asymptotic giant branch stars to have contributed significantly, providing a clean environment to isolate massive-star yields. We do not detect significant HF absorption (∼2σ) and derive a conservative 5σ upper limit of  NHF/NH2&lt;2.2×10−9 . This limit is about an order of magnitude below typical local measurements, indicating inefficient fluorine enrichment ∼0.9 Gyr after the Big Bang. Comparison with chemical evolution models shows that our constraint is consistent with scenarios without WR yields at this epoch. Expanding the sample of HF absorption measurements in high-redshift galaxies with well-characterized metallicities will be crucial for tracing the onset of WR enrichment and fluorine production across cosmic time.

Keywords: Starburst galaxies, Strong gravitational lensing, Chemical abundances, Millimeter-wave spectroscopy, High-redshift galaxies
Superluminal Wave Activation at Relativistic Magnetized Shocks. Fast radio bursts (FRBs) are extremely energetic radio transients, where some are generated in magnetar magnetospheres and winds. Despite a growing number of observations, their emission mechanisms remain elusive. It has recently been proposed that Alfvénic perturbations can convert into superluminal O-modes at magnetized shocks and propagate downstream as a radio signal. We validate this superluminal wave activation mechanism using pair-plasma theory and particle-in-cell simulations. Theory predicts two different downstream modes: nonpropagating Alfvénic perturbations and propagating superluminal O-modes. Superluminal wave activation occurs if the frequency of upstream perturbations in the shock frame exceeds the downstream plasma frequency. 1D particle-in-cell simulations confirm wavenumber and frequency jumps across the shock for upstream perturbations with frequencies well above the plasma frequency. Our simulations model both monochromatic upstream waves and broadband spectra with the downstream plasma frequency acting like a high-pass filter for superluminal O-modes. We discuss implications for FRB generation in relativistic magnetized winds.

Keywords: Magnetospheric radio emissions, Shocks, Plasma astrophysics, Magnetars, Radio transient sources
<SUP>56</SUP>Ni Production in Long-lived Binary Neutron Star Merger Remnants. We investigate the nucleosynthesis and kilonova emission based on numerical-relativity binary neutron star merger simulations that incorporate a two-moment neutrino-transport scheme. Unlike in previous works with simpler neutrino treatments, a massive, fast (up to v = 0.3c), proton-rich neutrino-driven wind develops in the postmerger phase of the simulations as long as the merger remnant does not collapse to a black hole. We evolve the ejecta for 100 days after the merger using 2D ray-by-ray radiation-hydrodynamics simulations coupled in situ to a complete nuclear network. The most abundant nucleosynthesis products are He, 56Ni, and 56Co. We find a total yield of ∼10−3M⊙ of 56Ni for all mergers that produce massive neutron star remnants, independently of the mass ratio and equations of state. After a few days, the decay of 56Ni and later 56Co becomes the primary source of heating in the matter expanding above the remnant. As a result, the kilonova light curve flattens on timescales of days for polar observation angles. This is an important effect that should be included in future models of kilonova light curves. Furthermore, the observation of a 56Ni─56Co feature could serve as a clear indicator for the presence of a long-lived neutron star remnant in future kilonova observations.

Keywords: Neutron stars, Explosive nucleosynthesis
Discovery of a Gas-enshrouded Broad-line Active Galactic Nucleus at z ∼ 7. The Lyα absorption profile in star-forming galaxies serves as a powerful tracer of the extended, dense neutral hydrogen in their surroundings during the Epoch of Reionization (EoR). We report a unique galaxy, A2744-z7DLA, at z ≍ 6.87, gravitationally lensed by the foreground galaxy cluster A2744, which exhibits both moderate Lyα emission and damped Lyα absorption, suggesting the presence of a dense neutral hydrogen environment. Our analysis suggests that the UV continuum turnover near Lyα is more likely shaped by a damped Lyα system rather than nebular continuum from the two-photon process. We analyze the physical properties of A2744-z7DLA with spectroscopic and photometric data from the JWST and the Hubble Space Telescope. The galaxy shows a compact morphology (re ∼ 0.3 kpc) and a broadened Hα emission line, suggesting possible active galactic nucleus (AGN) activity. The broad component of Hα has an FWHM of 2721 ± 200 km s−1, corresponding to a black hole mass of  MBH=2.90−1.28+2.35×107M⊙  and a black hole to stellar mass ratio of  log(MBH/M⊙)=−1.31−0.36+0.37 . The Balmer decrement (Hα/Hβ) yields a dust attenuation of AV ≍ 1.15 ± 0.23. Furthermore, we perform spectral energy distribution fitting using both stellar and AGN models. The results show that the UV and optical wavelengths are dominated by star-forming regions, while the AGN component contributes primarily at longer wavelengths. This work provides new insights into the interplay between star formation, neutral gas, and potential AGN activity in galaxies during the EoR.

Keywords: Reionization, Damped Lyman-alpha systems, Active galactic nuclei, High-redshift galaxies
New Approach to Superflare Energy Determination. We present a new method for estimating the total energy radiated by stellar flares in broadband continua, which assumes a constant emitting area but incorporates a time-dependent temperature evolution. This physically motivated approach offers an alternative to the commonly used method that assumes a fixed flare temperature of about 10,000 K and a variable area. By allowing the temperature to vary over time while keeping the emitting area constant, our method captures more realistic flare behavior. This time-dependent treatment of the flare temperature is supported by numerous solar observations, numerical simulations, and multiwavelength studies of active stars. We demonstrate that using peak flare temperatures estimated from a semi-empirical model grid, rather than assuming an ad hoc flare temperature value, improves the accuracy of total energy estimates. Although the most precise results still require multiband photometry/spectroscopy or independently constrained flare temperatures, our method offers a practical and scalable solution for single-band observations. It is particularly well suited for main-sequence stars of spectral types K4 and later with known effective temperatures. Finally, we discuss how the flare continuum behaves under varying chromospheric conditions. Our method improves flare energy estimates by incorporating a physically relevant time-dependent temperature evolution and empirically derived peak temperatures, rather than assuming a constant 10,000 K value. This modification reduces systematic errors that can reach factors of up to 10 as compared to previous estimates. We proved this on a sample of 50,320 TESS flares.

Keywords: Late-type stars