Sazuna/UAT_keywords huggingface dataset:
Detection of a 2.85 μm Feature on Five Spinel-rich Asteroids from JWST. Ground-based observations of "Barbarian" L-type asteroids at 1–2.5 μm indicate that their near-infrared spectra are dominated by the mineral spinel, which has been attributed to a high abundance of calcium-aluminum inclusions (CAIs)—the first solids to condense out of the protoplanetary disk during the formation of the solar system. However, the spectral properties of these asteroids from 2.5–5 μm, a wavelength region that covers signatures of hydrated minerals, water, and organics, have not yet been explored. Here, we present 2–5 μm reflectance spectra of five spinel-rich asteroids obtained with the NIRSpec instrument on the James Webb Space Telescope. All five targets exhibit a ∼2.85 μm absorption feature with a band depth of 3%–6% that appears correlated in strength with that of the 2 μm spinel absorption feature. The shape and position of the 2.85 μm feature are not a good match to the 2.7 μm feature commonly seen in carbonaceous CM meteorites or C-type asteroids. The closest spectral matches are to the Moon and Vesta, suggesting commonalities in aqueous alteration across silicate bodies, infall of hydrated material, and/or space weathering by solar wind H implantation. Lab spectra of CO/CV chondrites, CAIs, as well as the minerals cronstedtite and spinel, also show a similar feature, providing clues into the origin of the 2.85 μm feature.

Keywords: Asteroids, Infrared spectroscopy, Spectroscopy, Asteroid surfaces
Inferring the Interstellar Magnetic Field Direction from Energetic Neutral Atom Observations of the Heliotail. Determining the magnitude and direction of the interstellar magnetic field (B ISM) is a long-standing problem. To date, some methods to infer the direction and magnitude have utilized best-fit models to the positions of the termination shock and heliopause measured by Voyager 1 and 2. Other models use the circularity of the Interstellar Boundary Explorer (IBEX) ribbon assuming a secondary energetic neutral atom (ENA) mechanism. Previous studies have revealed that the B ISM organizes the orientation of the heliotail with respect to the solar meridian. Here we propose a new way to infer the direction of the B ISM based on ENA observations of the heliotail. IBEX observations of the heliotail have revealed high-latitude lobes of enhanced ENA flux at energies &gt;2 keV. Analyses showed that the high-latitude lobes are nearly aligned with the solar meridian, while also exhibiting a rotation with solar cycle. We show, using steady-state solar wind conditions, that the inclination of the lobes reproduced with commonly used values for the angle (α  BV ) between B ISM and the interstellar flow in the hydrogen deflection plane (40° &lt; α  BV  &lt; 60°) is inconsistent with the IBEX ENA observations. We report that 0° &lt; α  BV  &lt; 20° best replicates the heliotail lobe inclinations observed by IBEX. Additionally, our model results indicate that the variation of the solar magnetic field magnitude with solar cycle causes the longitudinal rotation of the lobes observed by IBEX by affecting the inclination of the lobes.

Keywords: Heliopause, Magnetohydrodynamics, Heliosphere, Termination shock, The Sun, Solar system, Interstellar magnetic fields, Interstellar medium, Heliosheath, Magnetohydrodynamical simulations
Discovery of the First Antiglitch Event in the Rotation-powered Pulsar PSR B0540-69. Using data from the Neutron star Interior Composition ExploreR observatory, we identified a permanent spin frequency decrease of Δν = ‑(1.04 ± 0.07) × 10‑7 Hz around MJD 60132 in the rotation-powered pulsar PSR B0540-69, which exhibits a periodic signal at a frequency of ν ∼ 19.6 Hz. This points to an antiglitch event, a sudden decrease of the pulsar's rotational frequency without any major alteration in the pulse profile or any significant increase of the pulsed flux. Additionally, no burst activity was observed in association with the antiglitch. To date, observations of the few known antiglitches have been made in magnetars or accreting pulsars. This is the first antiglitch detected in a rotation-powered pulsar. Given its radiatively quiet nature, this antiglitch is possibly of internal origin. Therefore, we tentatively frame this event within a proposed mechanism for antiglitches where the partial "evaporation" of the superfluid component leads to an increase in the normal component's moment of inertia and a decrease in the superfluid one.

Keywords: Neutron stars, Rotation powered pulsars, Compact objects, Pulsars
Emergence of Microphysical Bulk Viscosity in Binary Neutron Star Postmerger Dynamics. In nuclear matter in isolated neutron stars, the flavor content (e.g., proton fraction) is subject to weak interactions, establishing flavor (β-)equilibrium. However, there can be deviations from this equilibrium during the merger of two neutron stars. We study the resulting out-of-equilibrium dynamics during the collision by incorporating direct and modified Urca processes (in the neutrino-transparent regime) into general-relativistic hydrodynamics simulations with a simplified neutrino transport scheme. We demonstrate how weak-interaction-driven bulk viscosity in postmerger simulations can emerge and assess the bulk viscous dynamics of the resulting flow. We further place limits on the impact of the postmerger gravitational-wave strain. Our results show that weak-interaction-driven bulk viscosity can potentially lead to a phase shift of the postmerger gravitational-wave spectrum, although the effect is currently on the same level as the numerical errors of our simulation.

Keywords: Neutron stars, Nuclear astrophysics, Gravitational waves, Nuclear physics
Ultra-high-energy Cosmic-Ray Sources Can Be Gamma-Ray Dim. Ultra-high-energy cosmic rays (UHECRs), accelerated hadrons that can exceed energies of 1020 eV, are the highest-energy particles ever observed. While the sources producing UHECRs are still unknown, the Pierre Auger Observatory has detected a large-scale dipole anisotropy in the arrival directions of cosmic rays above 8 EeV. In this work, we explore whether resolved gamma-ray sources can reproduce the Auger dipole. We use various Fermi Large Area Telescope catalogs as sources of cosmic rays in CRPropa simulations. We find that in all cases, the simulated dipole has an amplitude significantly larger than that measured by Auger, even when considering large extragalactic magnetic field strengths and optimistic source weighting schemes. Our result implies that the resolved gamma-ray sources are insufficient to account for the population of sources producing the highest-energy cosmic rays, and there must exist a population of UHECR sources that lack gamma-ray emission or are unresolved by the current-generation gamma-ray telescopes.

Keywords: Gamma-ray sources, Ultra-high-energy cosmic radiation
A Millisecond Pulsar Binary Embedded in a Galactic Center Radio Filament. The Galactic center is host to a population of extraordinary radio filaments, thin linear structures that trace out magnetic field lines running perpendicular to the Galactic plane. Using Murriyang, the 64 m Parkes radio telescope, we conducted a search for pulsars centered on the position of a compact source in the filament G359.0‑0.2. We discovered a millisecond pulsar (MSP), PSR J1744‑2946, with a period P = 8.4 ms, that is bound in a 4.8 hr circular orbit around an M c &gt; 0.05 M ⊙ companion. The pulsar dispersion measure of 673.7 ± 0.1 pc cm‑3 and Faraday rotation measure of 3011 ± 3 rad m‑2 are the largest of any known MSP. Its radio pulses are moderately scattered due to multipath propagation through the interstellar medium, with a scattering timescale of 0.87 ± 0.08 ms at 2.6 GHz. Using MeerKAT, we localized the pulsar to a point source embedded in a low-luminosity radio filament, the "Sunfish", that is unrelated to G359.0‑0.2. Our discovery of the first MSP within 1° of the Galactic center hints at a large population of these objects detectable via high-frequency surveys. The association with a filament points to pulsars as the energy source responsible for illuminating the Galactic center radio filaments.

Keywords: Interstellar filaments, Galactic center, Binary pulsars, Pulsars
Exposing Line Emission: The Systematic Differences of Measuring Galaxy Stellar Masses with JWST NIRCam Medium versus Wide Band Photometry. Photometrically derived stellar masses are known to suffer from systematic uncertainties, particularly due to nebular emission contributions to the spectral energy distribution (SED). Using James Webb Space Telescope NIRCam imaging from the CAnadian NIRISS Unbiased Cluster Survey, we introduce a comparison study of photometrically derived redshifts and stellar masses based on two photometric catalogs of the same field spanning ∼0.4–4.5 μm: one consisting solely of wide band photometry, and another employing a combination of wide and medium band photometry. We find that ∼70% of likely line emitters have consistent photometric redshifts between both catalogs, with a median stellar mass difference between the two catalogs of &lt;0.2 dex across all redshift bins. There are, however, a subset of galaxies (5% at z ∼ 2 up to 15% at z ∼ 6) where wide bands underestimate emission line strengths and infer older stellar populations, leading to median stellar mass differences of ∼0.7 dex. Examination of the SEDs for galaxies with inconsistent photometric redshifts shows this is caused by the inability of the wide bands to distinguish continuum emission from emission lines. Computing a stellar mass density with our sample, we find that it is potentially underestimated using wide band photometry by ∼10%–20% at z &lt; 4, and potentially overestimated by as much as a factor of 2–3 at z &gt; 5. These systematic differences caused by the poor spectral resolution of wide bands have implications for both ongoing and future planned observing programs that determine stellar mass and other physical properties of high-redshift galaxies solely via wide band photometry.

Keywords: Broad band photometry, Galaxy properties, Medium band photometry, Spectral energy distribution, Photometry, Galaxy masses
Discovering the Mass-Scaled Damping Timescale from Microquasars to Blazars. Studying the variability of the accretion disks of black holes and jets is important to identify their internal physical processes. In this Letter, we obtain the characteristic damping timescale of 34 blazars and 7 microquasars from the Fermi-Large Area Telescope and the XMM-Newton X-ray telescope, respectively. We found that the mass-scaled characteristic timescales, ranging from the microquasars of stellar-mass black holes to the blazars of supermassive black holes, exhibited a linear relationship with a slope of ∼0.57. Given the fact the damping timescales of the γ-ray in the blazars are associated with the jet, we propose that the timescales of the X-ray in these microquasars are also related to the jet. The mass-scaled damping timescale that we found was consistent with the radiation of the optical accretion disk. This can be attributed to the viscous timescale at the ultraviolet-emitting radii of the disk, which can affect the jet. Our study provides a new perspective on the origin of the region of radiation and the possible disk─jet connection based on time-domain analysis.

Keywords: Blazars, Galaxy jets, Galaxy accretion disks, Astronomical methods
On the Heating of the Slow Solar Wind by Imbalanced Alfvén-wave Turbulence from 0.06 to 1 au: Parker Solar Probe and Solar Orbiter Observations. In this work we analyze plasma and magnetic field data provided by the Parker Solar Probe and Solar Orbiter missions to investigate the radial evolution of the heating of Alfvénic slow wind by imbalanced Alfvén-wave (AW) turbulent fluctuations from 0.06 to 1 au. in our analysis we focus on slow solar-wind intervals with highly imbalanced and incompressible turbulence (i.e., magnetic compressibility C  B  = δ B/B ≤ 0.25, plasma compressibility C  n  = δ n/n ≤ 0.25, and normalized cross helicity σ  c  ≥ 0.65). First, we estimate the AW turbulent dissipation rate from the wave energy equation and find that the radial profile trend is similar to the proton heating rate. Second, we find that the scaling of the empirical AW turbulent dissipation rate Q  W  obtained from the wave energy equation matches the scaling from the phenomenological AW turbulent dissipation rate Q CH09 (with Q CH09 ≃ 1.55Q  W ) derived by Chandran &amp; Hollweg based on the model of reflection-driven turbulence. Our results suggest that, as in the fast solar wind, AW turbulence plays a major role in the ion heating that occurs in incompressible slow-wind streams.

Keywords: Slow solar wind, Alfven waves, Interplanetary turbulence
Mechanisms of Fundamental Electromagnetic Wave Radiation in the Solar Wind. Large-scale and long-term two-dimensional particle-in-cell simulations performed for parameters relevant to type III solar radio bursts have provided new results on the generation mechanisms of fundamental electromagnetic waves radiated at the plasma frequency ω  p . The paper first considers the nonlinear wave interaction process of electromagnetic decay (EMD) in a homogeneous solar wind plasma with an electron-to-ion temperature ratio T  e /T  i  &gt; 1. The dynamics of ion-acoustic waves (dispersion, spectra, growth/damping) is studied, and signatures confirming the three-wave interactions (cross-bicoherence, correlations between waves' phases and between waves' growths, resonance conditions) are provided. The decisive role played in EMD by the backscattered Langmuir waves coming from the electrostatic decay (ESD) is demonstrated. EMD can be triggered by ion acoustic waves coming from the two cascades of the faster and more intense ESD. The same study is then performed in a solar wind plasma with random density fluctuations. In this case, EMD is not suppressed but develops only within plasma regions of reduced or quasi-uniform density. It coexists with linear mode conversion (LMC) of Langmuir waves into electromagnetic radiation, which is the fastest and most prominent process, as well as with ESD. LMC can lead to enhanced occurrence of EMD in the early stage. Moreover, the impact of T  e /T  i  on electromagnetic energy growth and saturation is shown to be rather weak. Ion-acoustic waves are heavily damped at T  e  ∼ T  i , so that EMD is overcome by nonlinear induced scattering on thermal ions. In actual solar wind plasmas, EMD should be more easily observed in plasma regions weakly perturbed by the background density turbulence and where ion temperature is decreased.

Keywords: Radio bursts, Solar wind, Solar electromagnetic emission
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Transmission Spectroscopy. Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (P orb) of 12.76 days. The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous P orb from TESS data. We confirmed the transit signal and P orb using ground-based photometry with MuSCAT2 and MuSCAT3, and validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host star is inactive, with an X-ray-to-bolometric luminosity ratio of . Joint analysis of the light curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R ⊕, a 3σ mass upper limit of 3.9 M ⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric (TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.

Keywords: Extrasolar rocky planets, High resolution spectroscopy, Astronomy data modeling, Exoplanets, Exoplanet astronomy, Space telescopes, Radial velocity, Transit photometry, Exoplanet atmospheres
Chemical Diagnostics to Unveil Environments Enriched by First Stars. Unveiling the chemical fingerprints of the first (Population III, hereafter Pop III) stars is crucial for indirectly studying their properties and probing their massive nature. In particular, very massive Pop III stars explode as energetic pair-instability supernovae (PISNe), allowing their chemical products to escape in the diffuse medium around galaxies, opening the possibility to observe their fingerprints in distant gas clouds. Recently, three z &gt; 6.3 absorbers with abundances consistent with an enrichment from PISNe have been observed with JWST. In this Letter, we present novel chemical diagnostics to uncover environments mainly imprinted by PISNe. Furthermore, we revise the JWST low-resolution measurements by analyzing the publicly available high-resolution X-Shooter spectra for two of these systems. Our results reconcile the chemical abundances of these absorbers with those from literature, which are found to be consistent with an enrichment dominated (&gt;50% metals) by normal Pop II SNe. We show the power of our novel diagnostics in isolating environments uniquely enriched by PISNe from those mainly polluted by other Pop III and Pop II SNe. When the subsequent enrichment from Pop II SNe is included, however, we find that the abundances of PISN-dominated environments partially overlap with those predominantly enriched by other Pop III and Pop II SNe. We dub these areas confusion regions. Yet, the odd─even abundance ratios [Mg,Si/Al] are extremely effective in pinpointing PISN-dominated environments and allowed us to uncover, for the first time, an absorber consistent with a combined enrichment by a PISN and another Pop III SN for all the six measured elements.

Keywords: Damped Lyman-alpha systems, Population III stars, Chemical abundances, Abundance ratios
Two Distinct Classes of Quiescent Galaxies at Cosmic Noon Revealed by JWST PRIMER and UNCOVER. We present a measurement of the low-mass quiescent size–mass relation at cosmic noon (1 &lt; z &lt; 3) from the JWST PRIMER and UNCOVER treasury surveys, which highlights two distinct classes of quiescent galaxies. While the massive population is well studied at these redshifts, the low-mass end has been previously underexplored due to a lack of observing facilities with sufficient sensitivity and spatial resolution. We select a conservative sample of low-mass quiescent galaxy candidates using rest-frame UVJ colors and specific star formation rate criteria and measure galaxy morphology in both rest-frame UV/optical wavelengths (F150W) and rest-frame near-infrared (F444W). We confirm an unambiguous flattening of the low-mass quiescent size–mass relation, which results from the separation of the quiescent galaxy sample into two distinct populations at $\mathrm{log}({M}_{\star }/{M}_{\odot })\sim 10.3$ : low-mass quiescent galaxies that are notably younger and have disky structures, and massive galaxies consistent with spheroidal morphologies and older median stellar ages. These separate populations imply mass quenching dominates at the massive end while other mechanisms, such as environmental or feedback-driven quenching, form the low-mass end. This stellar mass-dependent slope of the quiescent size–mass relation could also indicate a shift from size growth due to star formation (low masses) to growth via mergers (massive galaxies). The transition mass between these two populations also corresponds with other dramatic changes and characteristic masses in several galaxy evolution scaling relations (e.g., star formation efficiency, dust obscuration, and stellar-to-halo mass ratios), further highlighting the stark dichotomy between low-mass and massive galaxy formation.

Keywords: Galaxy quenching, James Webb Space Telescope, Galaxy structure, Galaxy evolution
Uncovering the Ghostly Remains of an Extremely Diffuse Satellite in the Remote Halo of NGC 253. We present the discovery of NGC253-SNFC-dw1, a new satellite galaxy in the remote stellar halo of the Sculptor Group spiral, NGC 253. The system was revealed using deep, resolved star photometry obtained as part of the Subaru Near-Field Cosmology Survey that uses the Hyper Suprime-Cam on the Subaru Telescope. Although rather luminous (M  V  = ‑11.7 ± 0.2) and massive (M * ∼ 1.25 × 107 M ⊙), the system is one of the most diffuse satellites yet known, with a half-light radius of R  h  = 3.37 ± 0.36 kpc and an average surface brightness of ∼30.1 mag arcmin‑2 within the R  h . The color–magnitude diagram shows a dominant, old (∼10 Gyr), and metal-poor ([M/H] = ‑1.5 ± 0.1 dex) stellar population, as well as several candidate thermally pulsing asymptotic giant branch stars. The distribution of red giant branch stars is asymmetrical and displays two elongated tidal extensions pointing toward NGC 253, suggestive of a highly disrupted system being observed at apocenter. NGC253-SNFC-dw1 has a size comparable to that of the puzzling Local Group dwarfs Andromeda XIX and Antlia 2 but is 2 magnitudes brighter. While unambiguous evidence of tidal disruption in these systems has not yet been demonstrated, the morphology of NGC253-SNFC-dw1 clearly shows that this is a natural path to produce such diffuse and extended galaxies. The surprising discovery of this system in a previously well-searched region of the sky emphasizes the importance of surface-brightness limiting depth in satellite searches. *This research is based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Keywords: Stellar photometry, Stellar populations, Galactic archaeology, Dwarf galaxies, Tidal disruption, Galaxy structure, Star counts
Subkiloparsec Scaling Relations between Hot Gas, Dense Gas, and Star Formation Rate in Five Nearby Star-forming Galaxies. Based on the newly acquired dense gas observations from the JCMT MALATANG survey and X-ray data from Chandra, we explore the correlation between hot gas and HCN J = 4 → 3 and HCO+ J = 4 → 3 emission for the first time at subkiloparsec scale of five nearby star-forming galaxies, namely M82, M83, IC 342, NGC 253, and NGC 6946. We find that both HCN J = 4 → 3 and HCO+ J = 4 → 3 line luminosity show a statistically significant correlation with the 0.5‑2 keV X-ray emission of the diffuse hot gas ( ${L}_{0.5-2\,\mathrm{keV}}^{\mathrm{gas}}$ ). The Bayesian regression analysis gives the best fit of $\mathrm{log}({L}_{0.5-2\,\mathrm{keV}}^{\mathrm{gas}}$ / $\mathrm{erg}\,{{\rm{s}}}^{-1})=2.39\,\mathrm{log}({L}_{\mathrm{HCN}(4-3)}^{{\prime} }$ /K km s‑1 pc2) + 24.83 and $\mathrm{log}({L}_{0.5-2\,\mathrm{keV}}^{\mathrm{gas}}$ / $\mathrm{erg}\,{{\rm{s}}}^{-1})=2.48\,\mathrm{log}({L}_{{\mathrm{HCO}}^{+}(4-3)}^{{\prime} }$ /K km s‑1 pc2) + 23.84, with dispersion of ∼0.69 dex and 0.54 dex, respectively. At the subkiloparsec scale, we find that the power-law index of the ${L}_{0.5-2\,\mathrm{keV}}^{\mathrm{gas}}$ ‑star formation rate (SFR) relation is $\mathrm{log}({L}_{0.5-2\,\mathrm{keV}}^{\mathrm{gas}}/\mathrm{erg}\,{{\rm{s}}}^{-1})=1.80\,\mathrm{log}(\mathrm{SFR}/{M}_{\odot }\,{\mathrm{yr}}^{-1})+39.16$ , deviated from previous linear relations at the global scale. This implies that the global property of hot gas significantly differs from individual resolved regions, which is influenced by the local physical conditions close to the sites of star formation.

Keywords: Star formation, Interstellar medium