Sazuna/UAT_keywords huggingface dataset:
Does DESI DR2 Challenge ΛCDM Paradigm?. Although the debate about the systematic errors of DESI DR1 is still open, recent DESI DR2 is consistent with DESI DR1 and further strengthens the results of DESI DR1. In our analysis, both the LRG1 point at zeff = 0.510 and the LRG3+ELG1 point at zeff = 0.934 are in tension with the ΛCDM-anchored value of Ωm inferred from Planck and the Type Ia supernovae compilations Pantheon+, Union3, and DES-SN5YR. For luminous red galaxy 1 (LRG1) the tensions are 2.42σ, 1.91σ, 2.19σ, and 2.99σ, respectively; for LRG3+emission line galaxy 1 (ELG1) they are 2.60σ, 2.24σ, 2.51σ, and 2.96σ, respectively. From low to high redshift bins, DESI DR2 shows improved consistency relative to DESI DR1: the Ωm tension decreases from 2.20σ to 1.84σ. However, DESI DR2 alone does not provide decisive evidence against the ΛCDM model, and the apparent signal is largely driven by specific tracers, LRG1 and LRG2. In the ω0ωaCDM analysis, including all tracers yields a posterior mean with ω0 &gt; −1, which aligns with scenarios of dynamical dark energy as a potential explanation and suggests that the DESI DR2 challenges the ΛCDM paradigm. While removing LRG1 and/or LRG2 fully restores ΛCDM concordance (i.e., ω0 → −1), we also find  ω0(LRG1)&gt;ω0(LRG2) , indicating LRG1 drives the apparent dynamical dark energy trend more strongly. Model selection using the natural log Bayes factor  lnBF≡ln(ZΛCDM/Zω0ωaCDM)  shows weak evidence for ΛCDM when LRG1, LRG2, or both are removed, and it is inconclusive for the full sample; thus, the data do not require the extra ωa freedom, and the apparent ω0 &gt; −1 preference should be interpreted cautiously as a manifestation of the ω0─ωa degeneracy under limited per tracer information.

Keywords: Cosmology, Cosmological evolution
Modeling Long-wavelength Amorphous Dust Emission Based on the Physically Motivated Soft-potential Model. We propose a new amorphous dust emission model based on the soft-potential (SP) model, applicable in the long-wavelength range from the far-infrared to the microwave. The SP model is widely accepted in material physics to explain amorphous thermal properties and is an extension of the two-level systems (TLS) model, which has been applied in interstellar amorphous dust physics. In the SP model, by assuming that some atoms composing amorphous dust are trapped in a double-well potential (DWP) described by a quartic function, the electric interaction can be solved directly, allowing the absorption cross section of the amorphous dust to be calculated. We present numerical and analytical solutions for the absorption cross section of amorphous dust and compare these results, finding good agreement for the DWP with a sufficiently high potential barrier. Our findings show that the SP model can reproduce the observed spectrum of the Perseus molecular cloud with slightly better accuracy than the conventional TLS model. Additionally, the SP model can more effectively explain various long-wavelength dust emission features, such as the spectrum flattening in the submillimeter range and anomalous microwave emission, compared to the TLS model. Further comparison and verification with observational data and laboratory measurements are necessary to refine the model.

Keywords: Interstellar dust, Dust physics, Millimeter astronomy, Far infrared astronomy, Dust continuum emission, Submillimeter astronomy
Detecting Molecular Hydrogen (H<SUB>2</SUB>) Emission at Cosmic Dawn. We present a theoretical framework for interpreting far-ultraviolet (FUV) fluorescent emission from molecular hydrogen (H2) in high-redshift galaxies, motivated by the unique capabilities of the James Webb Space Telescope (JWST) to probe the rest-frame FUV at cosmic dawn. Using the Meudon photodissociation region code, we model the H2 fluorescence spectrum under extreme interstellar medium (ISM) conditions in terms of high pressure (1011 K cm−3) and high radiation field (106 G0), combined with low metallicity (Z = 0.1 Z⊙) and high cosmic ionization rate (ζ = 10−14 s−1), characteristic of early galaxies. As a case study, we apply this framework to stacked NIRSpec spectra from the JWST Advanced Deep Extragalactic Survey for galaxies at redshifts z ≥ 7. The stacked spectrum exhibits emission features consistent in profile and wavelength with the predicted H2 fluorescence lines, including a blueshift suggestive of an outflow of molecular gas. Although individual features remain below robust detection thresholds, this demonstration illustrates the feasibility of using FUV fluorescence modeling to guide and interpret JWST spectroscopy of the molecular ISM at high redshift. Our framework provides a foundation for future searches for molecular hydrogen emission and the study of galactic feedback processes in the early Universe.

Keywords: Molecular gas, High-redshift galaxies
Signals of Bursts from the Very Early Universe. We consider possible observable signals from explosive events in the very early Universe, dubbed "bursts." These could be expected in connection with massive black hole or "baby Universe" formation. We anticipate that such major disruptions of spacetime would be associated with neutrino and perhaps other pulses. While these seem to be not detectable directly, we discuss how they could lead to potentially observable signals. We analyze how the pulses from very early times may "escape," that is, propagate to the last scattering epoch at the time tcmb and later, or alternatively be absorbed earlier, i.e., "contained." The possibly detectable signals include effects on small regions of the cosmic microwave background, a soft X-ray resulting from positron production, or a nonthermal addition to the relic neutrino background.

Keywords: Cosmic inflation
The Cosmic Shoreline Revisited: A Metric for Atmospheric Retention Informed by Hydrodynamic Escape. The "cosmic shoreline," a semi-empirical relation that separates airless worlds from worlds with atmospheres as proposed by K. J. Zahnle &amp; D. C. Catling, is now guiding large-scale JWST surveys aimed at detecting rocky exoplanet atmospheres. We expand upon this framework by revisiting the shoreline using existing hydrodynamic escape models applied to Earth-like, Venus-like, and steam atmospheres for rocky exoplanets, and we estimate energy-limited escape rates for CH4 atmospheres. We determine the critical instellation required for atmospheric retention by calculating time-integrated atmospheric mass loss. Our analysis introduces a new metric for target selection in the Rocky Worlds Director's Discretionary Time and refines expectations for rocky planet atmosphere searches. Exploring initial volatile inventory ranging from 0.01% to 1% of planetary mass, we find that its variation prevents the definition of a unique clear-cut shoreline, though nonlinear escape physics can reduce this sensitivity to initial conditions. Additionally, uncertain distributions of high-energy stellar evolution and planet age further blur the critical instellations for atmospheric retention, yielding broad shorelines. Hydrodynamic escape models find atmospheric retention is markedly more favorable for higher-mass planets orbiting higher-mass stars, with carbon-rich atmospheres remaining plausible for 55 Cancri e despite its extreme instellation. We caution that our estimates are sensitive to processes with poorly understood dynamics, such as atomic line cooling. Finally, we illustrate how density measurements can be used to statistically test the existence of the cosmic shorelines, emphasizing the need for more precise mass and radius measurements.

Keywords: Exoplanet atmospheres, Exoplanets, Exoplanet atmospheric evolution
Pinched Magnetic Fields in the High-mass Protocluster W3 IRS5. We present polarization maps of dust emission at 340 GHz in the luminous high-mass protocluster W3 IRS5, observed with the Submillimeter Array. The projected magnetic fields appear fairly organized, with a pinched morphology in the northern part and a concave shape in the southern part. We fit the polarization maps with a two-component magnetic field model: an hourglass model centered at the continuum peak, SMM2, and an empirical sphere centered at the O-type star, IRS7. Using the Davis─Chandrasekhar─Fermi method, we calculate a projected field strength of Bpos = 1.4 mG. Along with the Zeeman measurement, a total magnetic field strength of Btot = 1.6 mG is obtained. We find that gravitational energy is the most dominant, followed by magnetic energy and then turbulent energy. Small values of the virial parameter, αvir = 0.8, and the ratio of timescales, tff/tcross = 0.6, suggest an ongoing collapse. We also show collimated molecular outflows in the CO (3−2) and SiO (8−7) transitions. The morphology of the magnetic fields and the surrounding H II regions put forward a scenario for W3 IRS5. A gravitationally unstable dense core formed within a neutral gas ridge plowed by the expansions of W3 A and W3 B. The core began to contract, causing gravity to pull the magnetic field lines inward, which resulted in a pinched field morphology. The subsequent expansion of W3 F, ionized by IRS7, perturbed the magnetic field, creating the concave patterns. The dynamical interactions among protostars led to misalignment of their outflows.

Keywords: Massive stars, Star forming regions, Protostars, Stellar jets, Interstellar magnetic fields, Star formation, Radio interferometers, Submillimeter astronomy, Polarimetry
Diversity in Planetary Architectures from Pebble Accretion: Water Delivery to the Habitable Zone with Pebble Snow. "Pebble snow" describes a planet formation mechanism where icy pebbles in the outer disk reach inner planet embryos as the water-ice line evolves inward. We model the effects pebble snow has on sculpting planetary system architectures by developing the "PPOLs model." The model is capable of growing any number of protoplanet seed masses by pebble accretion simultaneously, and accounts for differences in rocky and icy pebble composition, the filtering of pebbles by other protoplanets, the pebble isolation mass, and a self-consistently evolving snow line. The growth and bulk composition are recorded across a grid of protoplanetary disks with stellar masses ranging from 0.125 to 2.0 M⊙ (M to A stars) and disk masses ranging from 1% to 40% of the stellar mass. Three system architectures emerge following a low, medium, and high disk mass fraction that remains consistent across stellar mass. The low-mass architecture is the only one to yield short-period Mars- to Earth-mass cores with bulk water content spanning orders of magnitude and may be a prelude to observed "peas in pod" systems. The high-mass architecture produces proto─gas giant cores in the outer disk. The medium-mass architecture produces a bimodal peak in mass within a system, with the outer protoplanet mass at the snow line growing to an order of magnitude larger, resembling the solar system. Solar system─like architectures appear for a small range of initial disk masses around F and G stars, but are not a common feature around K and M stars.

Keywords: Planetary system formation, Protoplanetary disks, Exoplanet systems
Atmospheric Gravity Waves Modulated by the Magnetic Field Configuration. Atmospheric gravity waves (AGWs) are buoyancy-driven waves excited by turbulent convection and contribute to the dynamics and energy transport of the lower solar atmosphere. We present high-resolution, multiwavelength observations from the Interferometric Bidimensional Spectrometer (IBIS) and the Solar Dynamics Observatory to investigate AGW behavior across different viewing geometries and magnetic field configurations. Using Fourier spectral analysis to compute phase differences and coherence spectra, we detect the signature of propagating AGWs carrying energy upward at temporal and spatial scales consistent with theory, simulations, and prior observations. Although AGW behavior is modulated by the magnetic field configuration, particularly the field inclination, these effects are not highly discernible in our observed kh─ν phase difference diagrams. After filtering to isolate the AGW regime, we compute spatial coherence-weighted phase difference maps and examine binned coherence-weighted phase differences as functions of the field strength and inclination. Our results show that AGWs are efficiently suppressed and/or reflected in intermediate-to-strong, vertically oriented fields in the upper photosphere, while they propagate rather freely in quiet-Sun and transverse fields. These findings agree with a simulated vertical 100 G field using CO5BOLD. Simulated kh─ν phase differences derived from a 3D magnetohydrodynamic dispersion relation also qualitatively agree with our upper photospheric IBIS diagnostics and reinforce that the magnetic field configuration modulates the propagation of AGWs. This work demonstrates the potential of AGWs as magnetoseismology diagnostics for probing average magnetic field properties in the lower solar atmosphere.

Keywords: Solar atmosphere, Solar photosphere, Solar physics, Solar magnetic fields, Solar oscillations
Investigating the Sulfur Mystery in Protoplanetary Disks through Chemical Modeling. Sulfur is a critical element to life on Earth, and with detections of sulfur-bearing molecules in exoplanets and comets, questions arise as to how sulfur is incorporated into planets in the first place. In order to understand sulfur's journey from molecular clouds to planets, we need to understand the molecular forms that sulfur takes in protoplanetary disks, where the rotational emission from sulfur-bearing molecules in the gas phase indicates a very low abundance. To address this question, we have updated the 2D time-dependent disk chemical modeling framework of J. K. J. Fogel et al. to incorporate several new sulfur species and hundreds of new sulfur reactions from the literature. Specifically, we investigate the main molecular forms that sulfur takes in a disk orbiting a solar-mass young T Tauri star. We explore the effects of different volatile (reactive) sulfur abundances, C/O ratios, initial sulfur molecular forms, and cosmic-ray ionization rates. We find that a high C/O ratio can explain both the prevalence of CS observed in disks and the lack of SO detections, consistent with previous results. Additionally, initial sulfur form greatly affects the ice abundances in the lower layers of the disk, which has implications for comet formation and future observations with JWST.

Keywords: Astronomical models, Chemical abundances, Astrochemistry, Protoplanetary disks, Planet formation
First Detection of Ices in Intermediate-mass Young Stellar Objects beyond the Milky Way. Using NIRSpec on JWST, we studied a sample of 15 intermediate-mass (1.8─4.1 M⊙) young stellar objects (YSOs) previously identified with MIRI photometry in the low-metallicity NGC 346 star-forming cluster in the Small Magellanic Cloud. All objects, observed in the 1.7─5.3 μm range, show strong hydrogen recombination lines in the Paschen, Brackett, Pfund, and Humphreys series, confirming their very young ages. The spectra of 11 YSOs show prominent absorption bands from the three most important ice species (H2O, CO2, CO), marking the first detection of these ices in intermediate-mass YSOs beyond our Galaxy. In three YSOs, water ice appears to be in crystalline form. In some objects, we also detect 13CO2 and OCS ices—never before observed beyond the Milky Way (MW)—and methanol ice in at least one star. We compared the column densities of H2O, CO2, and CO ices with those measured in more and less massive protostars in the MW and Large Magellanic Cloud, finding that, in NGC 346, ice column densities reach values nearly an order of magnitude lower than in more massive objects (∼1 × 1017 cm−2 for water and ∼1 × 1016 cm−2 for CO2 and CO). However, the relative proportions of the ice species abundances do not differ from those in massive MW YSOs. This suggests that metallicity may not significantly affect ice chemistry in protoplanetary disks and that, shielded by the protostellar envelope or deep in the midplane, circumstellar material is likely impervious to the radiation environment.

Keywords: Astrochemistry, Circumstellar matter, Young stellar objects, Star formation, Protostars, Magellanic Clouds, Star clusters
Turbulent Magnetic Fields and Molecular Cloud Interactions in the Supernova Remnant G1.9+0.3. We present on results of a spatially resolved spectral analysis of G1.9+0.3, the youngest known supernova remnant in the Galaxy. The X-ray spectra are well described by synchrotron emission from a power-law electron distribution with an exponential cutoff. We found a cutoff energy ϵ0 ∼ 1 keV in both the radio bright rim and the X-ray bright rims. In the loss-limited case, the cutoff energy depends on the shock velocity vsh and the Bohm factor η, following the relation  ϵ0∝vsh2η−1 . Our analysis shows that η ranges from 2 to 4 in the radio rim and from 12 to 15 in the X-ray rims. This suggests that the magnetic field in the radio rim is more turbulent than in the X-ray rims. The presence of CO clouds along the radio rim likely contributes to this difference. Interaction between the shock and these clouds can slow the shock down and generate turbulent eddies. The resulting turbulence eddies can amplify the magnetic field. We propose that the strong radio emission from the radio rim is primarily due to this amplified magnetic field. In contrast, a CO cloud located in the southwest appears to lie in the foreground, as indicated by its low turbulence and the absence of shock deceleration.

Keywords: Supernova remnants, Magnetic fields, Molecular clouds
Morphology of 35 Repeating Fast Radio Burst Sources at Microsecond Time Scales with CHIME/FRB. The Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) project has discovered the most repeating FRB sources of any telescope. However, most of the physical conclusions derived from this sample are based on data with a time resolution of ∼1 ms. In this work, we present for the first time a morphological analysis of the raw voltage data for 124 bursts from 35 of CHIME/FRB's repeating sources. We do not find any significant correlations among fluence, dispersion measure (DM), burst rate, and burst duration. Performing the first large-scale morphological comparison at timescales down to microseconds between our repeating sources and 125 nonrepeating FRBs, we find that repeaters are narrower in frequency and broader in duration than nonrepeaters, supporting previous findings. However, we find that the duration-normalized sub-burst widths of the two populations are consistent, possibly suggesting a shared physical emission mechanism. Additionally, we find that the spectral fluences of the two are consistent. When combined with the larger bandwidths and previously found larger DMs of nonrepeaters, this suggests that nonrepeaters may have higher intrinsic specific energies than repeating FRBs. We do not find any consistent increase or decrease in the DM (⪅1 pc cm−3 yr−1) and scattering timescales (⪅2 ms yr−1) of our sources over ∼2─4 yr periods.

Keywords: Radio telescopes, Radio transient sources
Evaluating the Contributions of Tianwen-1 Orbiter Tracking Data to the Mars Gravity Field Modeling. Mars gravity field models are critical data sets for studying the planet's internal structure. Currently, Mars gravity field determination is primarily based on modeling of tracking data from spacecraft such as Mars Reconnaissance Orbiter, Mars Odyssey, and Mars Global Surveyor. The Tianwen-1 mission has now been operational in orbit for over 3 yr. In this study, we construct a degree and order 120 gravity field model using Tianwen-1 spacecraft tracking data from 2021 June to 2024 October and perform a data fusion with the MRO120D gravity field model. Thereafter, we evaluate the contribution of Tianwen-1 tracking data to the improvement of the Martian gravity field modeling. Results indicate that the tracking data from Tianwen-1 provide limited enhancement to the low-degree terms of the gravity field. The relative errors in low-degree terms up to degree 10 of the fused model range from 10−6 to 10−4, and the formal uncertainties up to degree 6 are consistent with those of MRO120F model. The maximum difference in gravity anomalies at the Mars surface reaches 4.5 mGal, while the maximum discrepancy in gravity anomaly errors is approximately 0.65 mGal. The orbit determination performance for the Tianwen-1 spacecraft remains consistent between the two models. Currently, the accuracy improvement in the Martian static gravity field modeling achieved through Earth-based tracking data is relatively modest. Future significant advancements in Martian static gravity field modeling should focus on novel measurement techniques, such as satellite-to-satellite tracking, gravity gradiometry, and an accelerometer on board the spacecraft.

Keywords: Gravitational fields, Mars, Orbit determination
Surface Waves at Switchback Boundaries in the Young Solar Wind from Parker Solar Probe Observations. Switchbacks (SBs) are localized magnetic field deflections in the solar wind, marked by abrupt changes in the magnetic field direction relative to the ambient solar wind. Observations on board Parker Solar Probe (PSP) at heliocentric distances below 50 solar radii RS showed that within SBs, perturbations in the magnetic field ( ∆B ) and the bulk solar wind velocity ( ∆V ) align, i.e.,  ∆B∼∆V , producing enhanced radial velocity spikes. In this study, we examine the characteristics of SB boundaries, with particular attention to the role of boundary shear flow instabilities (Kelvin─Helmholtz instability; KHI) for surface wave phenomena based on the in situ magnetic field, plasma speed, and plasma density measurements from PSP. The results indicate that SB boundaries can be unstable for generating KHI-driven surface waves, suggesting that the wave activity observed at SB boundaries is caused by shear flow instabilities. In addition, the continued development of KHI may lead to boundary erosion, contributing to the radial evolution of SBs via structural weakening or broadening. However, when  ∆B  and  ∆V  are closely aligned, the boundary remains stable unless the velocity shear significantly exceeds the magnetic shear. Since the observed velocity shear typically ranges from 40% to 90% of magnetic shear, the instability condition is generally not satisfied. Thus, the configuration leading to the instability arises from deviations from precise alignment of  ∆B  and  ∆V  in the young solar wind, and the release of the KHI presumably leads to the formation of the  ∆B  and  ∆V  alignment observed at SB boundaries located at 35─55 RS.

Keywords: Solar wind, Interplanetary magnetic fields
Testing the Kerr Paradigm via Synchrotron Radiation. General relativity has been tested in weak field regimes, but strong gravity regimes are still to be verified. The strong gravity regime with synchrotron radiation has not yet been explored. The nonthermal synchrotron emission traces the magnetic field and cosmic-ray electrons. This paper presents a test of a strong gravity regime using synchrotron radiation with two different spacetime metrics: Kerr and Cardoso, Pani, and Rico (CPR). We investigate the effects of variation in model parameters such as the spin, inclination angle, magnetic field, and nonthermal spectral index of the synchrotron radiation on flux density as a function of frequency as an observable, first in the Kerr and then in the CPR spacetime. We generate mock data observations and fit the model using Bayesian inference for both spacetimes. Assuming a uniform prior, analyzed synchrotron radiation with a Bayesian approach can distinguish Kerr and CPR spacetimes by constraining spin and deformation parameters. A Gaussian prior also allows for this distinction. However, if a Gaussian prior is used for the spin while keeping the deformation parameters uniform, only the spin can be constrained, making it impossible to differentiate between Kerr and CPR spacetime.

Keywords: Gravitation, General relativity, Kerr black holes