Sazuna/UAT_keywords huggingface dataset:
Confirming the Tidal Tails of the Young Open Cluster Blanco 1 with TESS Rotation Periods. Blanco 1 is an ≈130 Myr open cluster located 240 pc from the Sun, below the Galactic plane. Recent studies have reported the existence of diffuse tidal tails extending 50–60 pc from the cluster center based on the positions and velocities measured by Gaia. To independently assess the reality and extent of this structure, we used light curves generated from TESS full-frame images to search for photometric rotation periods of stars in and around Blanco 1. We detected rotation periods down to a stellar effective temperature of ≈3100 K in 347 of the 603 cluster member candidates for which we have light curves. For cluster members in the core and candidate members in the tidal tails, both within a temperature range of 4400–6200 K, 74% and 72% of the rotation periods, respectively, are consistent with the single-star gyrochronological sequence. In contrast, a comparison sample of field stars yielded gyrochrone-consistent rotation periods for only 8.5% of the stars. The tidal tail candidates' overall conformance to the core members' gyrochrone sequence implies that their contamination ratio is consistent with zero and &lt;0.33 at the 2σ level. This result confirms the existence of Blanco 1 tidal tails and doubles the number of Blanco 1 members for which there are both spatio-kinematic and rotation-based cluster membership verification. Extending the strategy of using TESS light curves for gyrochronology to other nearby young open clusters and stellar associations may provide a viable strategy for mapping out their dissolution and broadening the search for young exoplanets.

Keywords: Stellar photometry, Stellar ages, Tidal tails, Open star clusters, Stellar rotation
CLASSY. XI. Tracing Neutral Gas Properties Using UV Absorption Lines and 21 cm Observations. Rest-frame far-ultraviolet (FUV) observations from JWST are revolutionizing our understanding of the high-z galaxies that drove reionization and the mechanisms by which they accomplished it. To fully interpret these observations, we must be able to diagnose how properties of the interstellar medium (ISM; e.g., column density, covering fraction, and outflow velocity) directly relate to the absorption features produced. Using the high-signal-to-noise and high-resolution FUV spectra of 45 nearby star-forming galaxies from the Cosmic Origins Spectrograph Legacy Spectroscopic Survey, we present the largest uniform, simultaneous characterization of neutral and low-ionization state (LIS) interstellar UV absorption lines (O I, Si II, S II, C II, and Al II) across a wide range of galaxy properties. We also present 21 cm H I observations for 35 galaxies, multiple of which are gas-poor or nondetected, possibly indicating the onset of a post-starburst phase. We find that our simultaneous one-component Voigt profile fits are capable of accurately modeling the LIS absorption for ∼75% of galaxies, mitigating challenges associated with saturation, infilling, and degeneracies. While the most massive galaxies require additional components, our one-component fits return average properties of the absorbing gas and follow the scaling relations described by a single gas cloud. We explore connections between LIS absorption and direct tracers of the neutral ISM (O I, Lyα, and H I 21 cm), finding that C II most closely traces the neutral gas trends, while other ions exhibit weaker correlations. Given the challenges with directly observing H I at higher-z, we demonstrate that LIS absorption can be a powerful means to study the neutral ISM and present empirical relationships for predicting neutral gas properties. ∗ Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Keywords: Interstellar line absorption, Ultraviolet spectroscopy, Lyman-alpha galaxies, High-redshift galaxies, Galaxies
Implementation of Aerosol Mie Scattering in POSEIDON with Application to the Hot Jupiter HD 189733 b's Transmission, Emission, and Reflected Light Spectrum. Aerosols are a ubiquitous feature of planetary atmospheres and leave clear spectral imprints in exoplanet spectra. Pre-JWST, exoplanet retrieval frameworks mostly adopted simple parametric approximations. With JWST, we now have access to mid-infrared wavelengths where aerosols have detectable composition-specific resonance features. Here, we implement new features into the open-source atmospheric retrieval code POSEIDON to account for the complex scattering, reflection, and absorption properties of Mie-scattering aerosols. We provide an open-source database of these Mie-scattering cross sections and optical properties. We also extend the radiative transfer and retrieval functionality in POSEIDON to include multiple scattering reflection and emission spectroscopy. We demonstrate these new retrieval capabilities on archival Hubble and Spitzer transmission and secondary-eclipse spectra of the hot Jupiter HD 189733 b. We find that a high-altitude, low-density, and thin slab composed of submicron particles is necessary to fit HD 189733 b's transmission spectrum, with multiple aerosol species providing a good fit. We additionally retrieve a subsolar H2O abundance, a subsolar K abundance, and do not detect CO2. Our joint thermal and reflection retrievals of HD 189733 b's secondary-eclipse spectrum, however, finds no evidence of dayside aerosols, a subsolar dayside H2O abundance, enhanced CO2, or slightly subsolar alkali abundances. We additionally explore how retrieval model choices such as cloud parameterization, aerosol species and properties, and thermal structure parameterization affect retrieved atmospheric properties. Upcoming JWST data for hot Jupiters such as HD 189733 b will be well suited to enable deeper exploration of aerosol properties, allowing the formulation of a self-consistent, multidimensional picture of cloud formation processes.

Keywords: Exoplanet atmospheric composition , Hot Jupiters, Exoplanets, Transmission spectroscopy, Radiative transfer, Spectroscopy, Exoplanet atmospheres
MHD Modeling of a Geoeffective Interplanetary Coronal Mass Ejection with the Magnetic Topology Informed by In Situ Observations. Variations of the magnetic field within a solar coronal mass ejection (CME) in the heliosphere depend on the CME's magnetic structure as it leaves the solar corona and its interplanetary evolution. To account for this evolution, we developed a new numerical model of the inner heliosphere that simulates the propagation of a CME through a realistic solar wind background and allows various CME magnetic topologies. To this end, we incorporate the Gibson–Low CME model within our global MHD model of the inner heliosphere, GAMERA-Helio. We apply the model to study the propagation of the geoeffective CME that erupted on 2010 April 3, aiming to reproduce the temporal variations of the magnetic field vector during the CME's passage by Earth. Parameters of the Gibson–Low CME are informed by STEREO white-light observations near the Sun. The magnetic topology for this CME—the tethered flux rope—is informed by in situ magnetic field observations near Earth. We performed two simulations testing different CME propagation directions. For an in-ecliptic direction, the simulation shows a rotation of all three magnetic field components within the CME, as seen at Earth, similar to that observed. However, the magnitudes of the components, particularly at the back of the CME, are underestimated by the model. With a southward direction, suggested by coronal imaging observations, the B  x  component lacks the observed change from negative to positive. In both cases, the model favors the east–west orientation of the flux rope, consistent with the orientation previously inferred from the images from STEREO/Heliospheric Imager.

Keywords: Space weather, Magnetohydrodynamics, Solar coronal mass ejections, Heliosphere
The Lyα Dependence on Nebular Properties from the HETDEX and MOSDEF Surveys. Investigating the impact of galaxy properties on emergent Lyα emission is crucial for reionization studies, given the sensitivity of Lyα to neutral hydrogen. This study presents an analysis of the physical characteristics of 155 star-forming galaxies, 29 with Lyα detected, and 126 with Lyα not detected with Lyα EW &lt; 20 Å, at z = 1.9–3.5, drawn from the MOSFIRE Deep Evolution Field survey, that have overlapping observations from the Hobby–Eberly Telescope Dark Energy Experiment survey. To unravel the interstellar medium (ISM) conditions in our sample, we developed a custom nebular line modeling algorithm based on the MAPPINGS V photoionization model grid and the emcee framework. Combining nebular-based ISM properties with photometry-based global properties, constrained via Bagpipes, we explore distinctions in the stellar and gas properties between Lyα-detected and Lyα-nondetected galaxies. Our analysis reveals statistically significant differences between the two samples in terms of stellar mass and dust attenuation (A  V ) at &gt;2σ significance, as determined via a Kolmogorov–Smirnov test. Moreover, there are weaker (≲1σ significance) indications that the ionization parameter and metallicity differ between the two samples. Our results demonstrate that the escape fraction of Lyα ( ) is inversely correlated with stellar mass, star formation rate, and dust attenuation, while it is positively correlated with the ionization parameter, with significance levels exceeding 2σ. Our findings suggest that the interstellar environments of Lyα-detected galaxies, characterized by low mass, low dust, low gas-phase metallicity, and high ionization parameters, play a pivotal role in promoting the escape of Lyα radiation.

Keywords: Lyman-alpha galaxies, Galaxy properties, Galaxies
Kink Instability of Flux Ropes in Partially Ionized Plasmas. In the solar atmosphere, flux ropes are subject to current-driven instabilities that are crucial in driving plasma eruptions, ejections, and heating. A typical ideal magnetohydrodynamics instability developing in flux ropes is the helical kink, which twists the flux rope axis. The growth of this instability can trigger magnetic reconnection, which can explain the formation of chromospheric jets and spicules, but its development has never been investigated in a partially ionized plasma (PIP). Here, we study the kink instability in PIP to understand how it develops in the solar chromosphere, where it is affected by charge-neutral interactions. Partial ionization speeds up the onset of the nonlinear phase of the instability, as the plasma β of the isolated plasma is smaller than the total plasma β of the bulk. The distribution of the released magnetic energy changes in fully ionized plasma and PIP, with a larger increase in internal energy associated with the PIP cases. The temperature in PIP increases faster also due to heating terms from the two-fluid dynamics. PIP effects trigger kink instability on shorter time scales, which is reflected in more explosive chromospheric flux rope dynamics. These results are crucial to understanding the dynamics of small-scale chromospheric structures—minifilament eruptions—that thus far have been largely neglected but could significantly contribute to chromospheric heating and jet formation.

Keywords: Solar chromosphere, Solar magnetic reconnection
Observations of the Crustal Mini-magnetopause Reconnection at Mars. Magnetopause reconnection is a fundamental mechanism for mass and energy transfer in terrestrial planetary systems. Unlike Earth, Mars lacks a global magnetic field and instead has localized crustal magnetic fields, which can create structures morphologically similar to a scaled-down intrinsic magnetosphere, potentially forming mini-magnetospheres. In this study, we investigate reconnection in Martian mini-magnetospheres on the dayside, analyzing key characteristics of the reconnecting current sheet, and the associated ion escape rate, and comparing these features to reconnection events at the induced magnetopause documented in previous studies. Our observations reveal that, in the subsolar region, the thickness of the Martian mini-magnetopause is comparable to the upstream proton inertial length and the convective gyroradius of the magnetosheath solar wind. However, at higher solar zenith angles, this thickness increases to several times these characteristic lengths. Reconnection-driven ion escape rates at the induced magnetopause are at least 1 order of magnitude greater than those associated with mini-magnetopause reconnection. These findings provide new insights into reconnection processes at Martian boundary layers.

Keywords: Magnetic fields, Planetary boundary layers
Differential Rotation of Individual Sunspots and Pores. The analysis of the rotation rate of individual sunspots and pores was performed according to the data from the processing of observations by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager in the period 2010–2024. Sunspots stood out in the images in the continuum. To accurately track the spots, we processed five images for each day. To determine the polarity of the magnetic field, we superimposed the contours of sunspots on observations of magnetic fields at the same time. This made it possible to track the movement of more than 210,000 individual sunspots and pores. It is found that the rotation rate is influenced by the rotation rate of the solar atmosphere and the systematic proper motions of the spots. Sunspots and pores of the leading polarity have a rate of meridional movement ≈2.4% faster than spots of the trailing polarity. We also found that regular sunspots, which have umbrae and penumbrae, rotate ≈1.5% faster than solar pores, in which penumbrae are absent. The dependence of the rotation rate on the area is found. For sunspots with an area of S &gt; 10 μhm, the rotation rate is practically independent of the area. Small sunspots, with an area of S &lt; 10 μhm, rotate ≈1.7% more slowly.

Keywords: Solar differential rotation, Sunspots, Bipolar sunspot groups
Insights into the Long-term Flaring Events of Blazar PKS 0805-07: A Multiwavelength Analysis Over the Period of 2009–2023. We conducted a comprehensive temporal and spectral study of the FSRQ PKS 0805-07 by using broadband observations from the Fermi-LAT and Swift-XRT/UVOT instruments over the period of MJD 54684-60264. The 3 day binned γ-ray light curve during the active state revealed 11 distinct peak structures with the maximum integral flux (E &gt; 100 MeV) reached (1.56 ± 0.16) × 10‑6 photons cm‑2 s‑1 on MJD 59904.5. The shortest observed γ-ray variability was 2.80 ± 0.77 days. A correlation analysis between the γ-ray spectral index and flux indicated the typical trend of hardening when the source is brighter, commonly observed in blazars. We identified a lag of 121 (+27.21, ‑3.51) days in the spectral index relative to the flux, within the time interval MJD 59582 to 60112. The Anderson–Darling test and histogram fit rejected the normality of the γ-ray flux distribution and instead suggested a log-normal distribution. To gain insight into the underlying physical processes, we extracted broadband spectra from different time periods in the light curve. The spectral energy distribution during various flux states was well-reproduced using synchrotron, synchrotron-self-Compton, and external-Compton emissions from a broken power-law electron distribution. The seed photons required for the external Compton process are from the IR region. A comparison of the best-fit physical parameters indicated that the variations in different flux states were primarily associated with an increase in the bulk Lorentz factor and magnetic field from low to high flux states.

Keywords: Gamma-ray sources, Blazars, Active galaxies, Non-thermal radiation sources
A Census of Dwarf Galaxy Satellites around LMC-mass Galaxy NGC 2403. We present the first comprehensive census of the satellite population around a Large Magellanic Cloud stellar-mass galaxy, as part of the Magellanic Analog Dwarf Companions and Stellar Halos (MADCASH) survey. We have surveyed NGC 2403 (D = 3.0 Mpc) with the Subaru/Hyper Suprime-Cam imager out to a projected radius of 90 kpc (with partial coverage extending out to ∼110 kpc, or ∼80% of the virial radius of NGC 2403), resolving stars in the uppermost ∼2.5 mag of its red giant branch. By looking for stellar overdensities in the red giant branch spatial density map, we identify 149 satellite candidates, of which only the previously discovered MADCASH J074238+65201-dw is a bona fide dwarf, together with the more massive and disrupting satellite DDO 44. We carefully assess the completeness of our search via injection of artificial dwarf galaxies into the images, finding that we are reliably sensitive to candidates down to M  V  ∼ ‑7.5 mag (and somewhat sensitive to even fainter satellites). A comparison of the satellite luminosity function of NGC 2403 down to this magnitude limit to theoretical expectations shows overall good agreement. This is the first of a full sample of 11 Magellanic Cloud–mass host galaxies we will analyze, creating a statistical sample that will provide the first quantitative constraints on hierarchical models of galaxy formation around low-mass hosts. * This research is based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Keywords: Stellar photometry, Galaxy dark matter halos, Tidal disruption, Dwarf galaxies, Galaxy interactions, Galaxy stellar halos, Dwarf spheroidal galaxies, Magellanic Clouds
A Rapidly Accreting Active Galactic Nucleus Hidden in a Dust-obscured Galaxy at z ∼ 0.8. Dust-obscured galaxies (DOGs) containing central supermassive black holes (SMBHs) that are rapidly accreting (i.e., having high Eddington ratios, λ Edd) may represent a key phase closest to the peak of both the black hole and galaxy growth in the coevolution framework for SMBHs and galaxies. In this work, we present a 68 ks XMM-Newton observation of the high-λ Edd DOG J1324+4501 at z ∼ 0.8, which was initially observed by Chandra. We analyze the XMM-Newton spectra jointly with archival Chandra spectra. In performing a detailed X-ray spectral analysis, we find that the source is intrinsically X-ray luminous with  /erg   and heavily obscured with  . We further utilize UV-to-IR archival photometry to measure and fit the source's spectral energy distribution to estimate its host-galaxy properties. We present a supplementary comparison sample of 21 X-ray luminous DOGs from the XMM-SERVS survey with sufficient (&gt;200) 0.5─10 keV counts to perform a similarly detailed X-ray spectral analysis. Of the X-ray luminous DOGs in our sample, we find that J1324+4501 is the most remarkable, possessing one of the highest X-ray luminosities, column densities, and star formation rates. We demonstrate that J1324+4501 is in an extreme evolutionary stage where SMBH accretion and galaxy growth are at their peaks.

Keywords: AGN host galaxies, Active galaxies, X-ray active galactic nuclei
Exploring Pulsar Timing Precision: A Comparative Study of Polarization Calibration Methods for NANOGrav Data from the Green Bank Telescope. Pulsar timing array experiments have recently uncovered evidence for a nanohertz gravitational wave background by precisely timing an ensemble of millisecond pulsars. The next significant milestones for these experiments include characterizing the detected background with greater precision, identifying its source(s), and detecting continuous gravitational waves from individual supermassive black hole binaries. To achieve these objectives, generating accurate and precise times of arrival of pulses from pulsar observations is crucial. Incorrect polarization calibration of the observed pulsar profiles may introduce errors in the measured times of arrival. Further, previous studies have demonstrated that robust polarization calibration of pulsar profiles can reduce noise in the pulsar timing data and improve timing solutions. In this paper, we investigate and compare the impact of different polarization calibration methods on pulsar timing precision using three distinct calibration techniques: the Ideal Feed Assumption (IFA), Measurement Equation Modeling (MEM), and Measurement Equation Template Matching (METM). Three NANOGrav pulsars—PSRs J1643‑1224, J1744‑1134, and J1909‑3744—observed with the 800 MHz and 1.5 GHz receivers at the Green Bank Telescope (GBT) are utilized for our analysis. Our findings reveal that all three calibration methods enhance timing precision compared to scenarios where no polarization calibration is performed. Additionally, among the three calibration methods, the IFA approach generally provides the best results for timing analysis of pulsars observed with the GBT receiver system. We attribute the comparatively poorer performance of the MEM and METM methods to potential instabilities in the reference noise diode coupled to the receiver and temporal variations in the profile of the reference pulsar, respectively.

Keywords: Astronomical techniques, Pulsar timing method, Millisecond pulsars
Halfway to the Peak: The JWST MIRI 5.6 μm Number Counts and Source Population. We present an analysis of eight JWST Mid-Infrared Instrument (MIRI) 5.6 μm images with 5σ depths of ≈0.1 μJy. We detect 2854 sources within our combined area of 18.4 arcmin2. We compute the MIRI 5.6 μm number counts, including an analysis of the field-to-field variation. Compared to earlier published MIRI 5.6 μm counts, our counts have a more pronounced knee, at roughly 2 μJy. The location and amplitude of the counts at the knee are consistent with the Cowley et al. model predictions, although these models tend to overpredict the counts below the knee. In areas of overlap, 84% of the MIRI sources have a counterpart in the COSMOS2020 catalog. These MIRI sources have redshifts that are mostly in the z ∼ 0.5–2, with a tail out to z ∼ 5. They are predominantly moderate to low stellar masses (108–1010 M ⊙) main-sequence star-forming galaxies, suggesting that with ≈2 hr exposures, MIRI can reach well below M * at cosmic noon and reach higher mass systems out to z ∼ 5. Nearly 70% of the COSMOS2020 sources in areas of overlap now have a data point at 5.6 μm (rest-frame near-IR at cosmic noon), which allows for more accurate stellar population parameter estimates. Finally, we discovered 31 MIRI-bright sources not present in COSMOS2020. A crossmatch with IRAC channel 1 suggests that 10%–20% of these are likely lower mass (M * ≈ 109 M ⊙), z ∼ 1 dusty galaxies. The rest (80%–90%) are consistent with more massive but still very dusty galaxies at z &gt; 3.

Keywords: Infrared galaxies
Exploring Lenticular Galaxy Formation in Field Environments Using NewHorizon: Evidence for Counterrotating Gas Accretion as a Formation Channel. The formation pathways of lenticular galaxies (S0s) in field environments remain a matter of debate. We utilize the cosmological hydrodynamic simulation, NewHorizon, to investigate the issue. We select two massive star formation quenched S0s as our main sample. By closely tracing their physical and morphological evolution, we identify two primary formation channels: mergers and counterrotating gas accretion. The former induces central gas inflow due to gravitational and hydrodynamic torques, triggering active central star formation, which quickly depletes the gas of the galaxy. Counterrotating gas accretion overall has a similar outcome but more exclusively through hydrodynamic collisions between the preexisting and newly accreted gas. Both channels lead to S0 morphology, with gas angular momentum cancellation being a crucial mechanism. These formation pathways quench star formation on a short timescale (&lt;Gyr) compared to the timescales of environmental effects. We also discuss how counterrotating gas accretion may explain the origin of S0s with ongoing star formation and the frequently observed gas–star misaligned kinematics in S0s.

Keywords: Galaxy formation, Galaxy dynamics, Galaxy evolution, Galaxy mergers, Galaxy quenching