adsabs/SciX_UAT_keywords huggingface dataset:
Long-term Evolution of Nonthermal Emission from Type Ia and Core-collapse Supernova Remnants in a Diversified Circumstellar Medium

The contribution of galactic supernova remnants (SNRs) to the origin of cosmic rays (CRs) is an important open question in modern astrophysics. Broadband nonthermal emission is a useful proxy for probing the energy budget and production history of CRs in SNRs. We conduct hydrodynamic simulations to model the long-term SNR evolution from explosion all the way to the radiative phase (or 3 × 105 yr at maximum) and compute the time evolution of the broadband nonthermal spectrum to explore its potential applications on constraining the surrounding environments, as well as the natures and mass-loss histories, of the SNR progenitors. A parametric survey is performed on the ambient environments separated into two main groups, namely, a homogeneous medium with a uniform gas density and one with the presence of a circumstellar structure created by the stellar wind of a massive red supergiant progenitor star. Our results reveal a highly diverse evolution history of the nonthermal emission closely correlated to the environmental characteristics of an SNR. Up to the radiative phase, the roles of CR reacceleration and ion-neutral wave damping on the spectral evolution are investigated. Finally, we make an assessment of the future prospect of SNR observations by the next-generation hard X-ray space observatory FORCE and predict what we can learn from their comparison with our evolution models.

Keywords: galactic cosmic rays; non-thermal radiation sources; circumstellar matter; interstellar medium; supernova remnants
Regions of Suppressed Diffusion around Supernova Remnants?

The recent discovery of the so-called TeV halos has attracted much attention. The morphology of the emission requires that the region is characterized by severe suppression of the diffusion coefficient. This finding raises many questions as to its origin: (1) is the suppressed diffusion to be attributed to instabilities induced by the same radiating particles? (2) or does it actually show that the diffusion coefficient is small throughout the disk of the Galaxy? In both cases, one would expect that the surroundings of supernova remnants (SNRs) should also show evidence of a reduced diffusion coefficient since most remnants are located in the disk and are expected to be sites of effective particle acceleration. Should we expect the existence of regions of extended γ-ray emission from these regions as well? Here, we investigate the transport of cosmic rays (CRs) that have escaped from SNRs in order to assess the viability of the idea of having a cocoon of suppressed diffusion around them. A comparison of our results with the γ-ray emission from the regions around HB9 and W28 does not provide solid evidence of reduced diffusivity. However, if indeed the phenomenon of reduced diffusivity occurs around SNRs surrounded by molecular clouds, our calculations show that the effects on the grammage of Galactic CRs can be significant.

Keywords: supernova remnants; galactic cosmic rays
Determining Model-independent H0 and Consistency Tests

We determine the Hubble constant H0 precisely (2.3% uncertainty) in a manner independent of the cosmological model through Gaussian process regression, using strong lensing and supernova data. Strong gravitational lensing of a variable source can provide a time-delay distance DΔt and angular diameter distance to the lens Dd. These absolute distances can anchor Type Ia supernovae, which give an excellent constraint on the shape of the distance-redshift relation. Updating our previous results to use the H0LiCOW program's milestone data set consisting of six lenses, four of which have both DΔt and Dd measurements, we obtain ${H}_{0}={72.8}_{-1.7}^{+1.6}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ for a flat universe and ${H}_{0}={77.3}_{-3.0}^{+2.2}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ for a non-flat universe. We carry out several consistency checks on the data and find no statistically significant tensions, though a noticeable redshift dependence persists in a particular systematic manner that we investigate. Speculating on the possibility that this trend of derived Hubble constant with lens distance is physical, we show how this can arise through modified gravity light propagation, which would also impact the weak lensing σ8 tension.

Keywords: hubble constant; observational cosmology; strong gravitational lensing; hubble diagram
The TESS Phase Curve of KELT-1b Suggests a High Dayside Albedo

We measured the optical phase curve of the transiting brown dwarf KELT-1b (TOI 1476) using data from the TESS spacecraft. We found that KELT-1b shows significant phase variation in the TESS bandpass, with a relatively large phase amplitude of ${234}_{-44}^{+43}$ ppm and a secondary eclipse depth of ${371}_{-49}^{+47}$ ppm. We also measured a marginal eastward offset in the dayside hot spot of 18°3 ± 7°4 relative to the substellar point. We detected a strong phase-curve signal attributed to ellipsoidal distortion of the host star with an amplitude of 399 ± 19 ppm. Our results are roughly consistent with the Spitzer phase curves of KELT-1b, but the TESS eclipse depth is deeper than expected. Our cloud-free 1D models of KELT-1b's dayside emission are unable to fit the full combined eclipse spectrum. Instead, the large TESS eclipse depth suggests that KELT-1b may have a significant dayside geometric albedo of Ag ∼ 0.5 in the TESS bandpass, which would agree with the tentative trend between equilibrium temperature and geometric albedo recently suggested by Wong et al. We posit that if KELT-1b has a high dayside albedo, it is likely due to silicate clouds that form on KELT-1b's nightside and are subsequently transported onto the western side of KELT-1b's dayside hemisphere before breaking up.

Keywords: brown dwarfs; exoplanet atmospheres; exoplanet atmospheric composition; hot jupiters
Anatomy of Photoevaporation Base: Linking the Property of the Launched Wind to Irradiation Flux

Ultraviolet and X-rays from radiation sources disperse nearby gas clumps by driving winds due to heating associated with the photochemical processes. This dispersal process, photoevaporation, constrains the lifetimes of the parental bodies of stars and planets. To understand this process in a universal picture, we develop an analytical model that describes the fundamental physics in the vicinity of the wind-launching region. The model explicitly links the density and velocity of photoevaporative winds at the launch points to the radiation flux reaching the wind-launching base, using a jump condition. The model gives a natural boundary condition for the wind-emanating points. We compare the analytical model with the results of radiation hydrodynamic simulations, where a protoplanetary disk is irradiated by the stellar extreme-ultraviolet, and confirm good agreement of the base density and velocity, and radial profiles of mass-loss rates. We expect that our analytical model is applicable to other objects subject to photoevaporation not only by extreme-ultraviolet but by far-ultraviolet/X-rays with suitable modifications. Future self-consistent numerical studies can test the applicability.

Keywords: protoplanetary disks; interstellar medium wind; h ii regions; hydrodynamical simulations; hydrodynamics; astrophysical fluid dynamics; interdisciplinary astronomy
New Determinations of the Surface Abundances of HD 1909: Paper I: The Light Elements (from Helium to Sulfur)

New abundances for the elements helium to sulfur are derived for the brightest member of the spectroscopic binary HD 1909 using updated atomic data and spectrum synthesis. The majority of these elements are underabundant, the depletion factors appear in parenthesis: helium (0.02 times the solar helium abundance), carbon and oxygen (0.40 ⊙), neon (0.15 ⊙), magnesium (0.45 ⊙), aluminum (0.02 ⊙). silicon (0.50 ⊙) and sulfur (0.35 ⊙). In contrast, phosphorus is overabundant by a factor of 12.5 ⊙ and the silicon-phosphorus-sulfur triad is inverted. The lines of the companion are redshifted by about +122.5 km s-1 with respect to the B9 Hg star in the spectrum analyzed here.

Keywords: chemically peculiar stars; mercury-manganese stars
Which Galaxy Property is the Best Gauge of the Oxygen Abundance?

We present an extensive exploration of the impact of 29 physical parameters in the oxygen abundance for a sample of 299 star-forming galaxies extracted from the extended Calar Alto Legacy Integral Field Area Survey sample. We corroborate that the stellar mass is the physical parameter that better traces the observed oxygen abundance (i.e., the mass-metallicity relation; MZR), while other physical parameters could play a potential role in shaping this abundance, but with a lower significant impact. We find that the functional form that best describes the MZR is a third-order polynomial function. From the residuals between this best functional form and the MZR, we find that once considered the impact of the mass in the oxygen abundance, the other physical parameters do not play a significant secondary role in shaping the oxygen abundance in these galaxies (including the gas fraction or the star formation rate). Our analysis suggests that the origin of the MZR is related to the chemical enrichment evolution of the interstellar medium due, most likely, to the buildup of stellar mass in these star-forming galaxies.

Keywords: chemical abundances
Constraining Annihilating Dark Matter Mass by the Radio Continuum Spectral Data of a High-redshift Galaxy Cluster

In the past decade, the properties of annihilating dark matter models were examined by various kinds of data, including the data of gamma-rays, radio waves, X-rays, positrons, electrons, antiprotons and neutrinos. In particular, most of the studies focus on the data of our Galaxy, nearby galaxies (e.g., M31 galaxy) or nearby galaxy clusters (e.g., Fornax cluster). In this article, we examine the archival radio continuum spectral data of a relatively high-redshift galaxy cluster (A697 cluster) to constrain the properties of annihilating dark matter. We find that leptophilic annihilation channels (e+ e-, μ+ μ-, and τ+ τ-) can give very good fits to the radio continuum spectrum of the A697 cluster.

Keywords: dark matter; particle astrophysics
On the Thermally Pulsing Asymptotic Giant Branch Contribution to the Light of Nearby Disk Galaxies

The study of the luminosity contribution from thermally pulsing asymptotic giant branch (TP-AGB) stars to the stellar populations of galaxies is crucial to determine their physical parameters (e.g., stellar mass and age). We use a sample of 84 nearby disk galaxies to explore diverse stellar population synthesis models with different luminosity contributions from TP-AGB stars. We fit the models to optical and near-infrared (NIR) photometry, on a pixel-by-pixel basis. The statistics of the fits show a preference for a low-luminosity contribution (i.e., high mass-to-light ratio in the NIR) from TP-AGB stars. Nevertheless, for 30%-40% of the pixels in our sample a high-luminosity contribution (hence low mass-to-light ratio in the NIR) from TP-AGB stars is favored. According to our findings, the mean TP-AGB star luminosity contribution in nearby disk galaxies may vary with Hubble type. This may be a consequence of the variation of the TP-AGB mass-loss rate with metallicity, if metal-poor stars begin losing mass earlier than metal-rich stars, because of a pre-dust wind that precedes the dust-driven wind.

Keywords: galaxy evolution; spiral galaxies; galaxy photometry; galaxy stellar content; asymptotic giant branch stars
Global Morphology Distortion of the 2021 October 9 Coronal Mass Ejection from an Ellipsoid to a Concave Shape

This paper presents a study of a 2021 October 9 coronal mass ejection (CME) with multipoint imaging and in situ observations. We also simulate this CME from the Sun to Earth with a passive tracer to tag the CME's motion. The coronagraphic images show that the CME is observed as a full halo by SOHO and as a partial halo by STEREO-A. The heliospheric images reveal that the propagation speed of the CME approaches about 1° hr-1, suggesting a slow CME. With simulated results matching these observation results, the simulation discloses that as the CME ejects from the Sun out to interplanetary space, its global morphology is distorted from an ellipsoid to a concave shape owing to interactions with the bimodal solar wind. The cross section of the CME's flux rope structure transforms from a circular shape into a flat one. As a result of the deflection, the propagation direction of the CME is far away from the Sun-Earth line. This means that the CME flank (or the ICME leg) likely arrives at both Solar Orbiter and the L1 point. From the CME's eruption to 1 au, its volume and mass increase by about two orders and one order of magnitude, respectively. Its kinetic energy is about 100 times larger than its magnetic energy at 1 au. These results have important implications for our understanding of CMEs' morphology, as well as their space weather impacts.

Keywords: solar coronal mass ejections; interplanetary physics; solar wind; magnetohydrodynamics
Hall Fields and Current Systems of Magnetic Reconnection under Asymmetric Conditions

The Hall effect is a key component of collisionless reconnection. A previous study showed that a quadrupolar Hall pattern under symmetric conditions degenerates into a bipolar pattern under highly asymmetric conditions. We study the properties of Hall magnetic fields and current systems during three reconnection events observed by the Magnetospheric Multiscale mission at the dayside magnetopause. Although the asymptotic density ratio between the magnetosheath and magnetospheric plasmas is very high for all three events, clear quadrupolar Hall field patterns are observed in all three events. The quadrupolar Hall magnetic fields in the three events display their respective properties on the intensity asymmetry and the distributing location. Among these events, a quadrupolar Hall field pattern is observed for the first time in in situ observations: the magnetosheath Hall pattern occupies the whole midplane region, while the magnetosphere Hall pattern still exists under highly asymmetric conditions. Observations show that the plasma mixture modulates the density asymmetry in the Hall region, which can be very different from the asymptotic density asymmetry in the magnetosheath and magnetospheric inflow plasma. The analyses indicate that the different density asymmetry inside the Hall region, but not the asymptotic density asymmetry, is an exact indicator that explains the different observed Hall patterns. Based on the observed facts, we suggest that the three reconnection events studied here are in different phases of their development after they are triggered under highly asymmetric conditions. Our results provide new insights into how the Hall effect works with the evolution of asymmetry during reconnection.

Keywords: space plasmas; planetary magnetospheres
The Bimodal Distribution in Exoplanet Radii: Considering Varying Core Compositions and H2 Envelope's Sizes

Several models have been introduced in order to explain the radius distribution in exoplanet radii observed by Fulton et al. with one peak at ∼ 1.3{R}\oplus, the other at ∼ 2.4{R}\oplus, and the minimum at ∼ 1.75{R}\oplus . In this paper we focus on the hypothesis that the exoplanet size distribution is caused by stellar X-ray and ultraviolet (XUV)-induced atmospheric loss. We evolve 106 synthetic exoplanets by exposing them to XUV irradiation from synthetic zero-age main-sequence stars. For each planet we set a different interior composition, which ranged from 100 wt% Fe (very dense), through to 100 wt% MgSiO3 (average density), and to 100 wt% {H}2O ice (low density), with varying hydrogen envelope sizes that varied from 0 wt% (a negligible envelope) to 100 wt% (a negligible core). Our simulations were able to replicate the bimodal distribution in exoplanet radii. We argue that in order to reproduce the distribution by Fulton et al. it is mandatory for there to be a paucity of exoplanets with masses above ∼ 8{M}\oplus . Furthermore, our best-fit result predicts an initial flat distribution in exoplanet occurrence for {M}P≲ 8{M}\oplus with a strong deficiency for planets with ≲ 3{M}\oplus . Our results are consistent with the ∼ 1.3{R}\oplus radius peak mostly encompassing denuded exoplanets, while the ∼ 2.4{R}\oplus radius peak is mainly comprised of exoplanets with large hydrogen envelopes.

Keywords: exoplanets; super earths; mini neptunes
An Astrometric Planetary Companion Candidate to the M9 Dwarf TVLM 513-46546

Astrometric observations of the M9 dwarf TVLM 513-46546 taken with the VLBA reveal an astrometric signature consistent with a period of 221 ± 5 days. The orbital fit implies that the companion has a mass mp = 0.35-0.42 MJ, a circular orbit (e ≃ 0), a semimajor axis a = 0.28-0.31 au, and an inclination angle i = 71°-88°. The detected companion, TVLM 513b, is one of the few giant-mass planets found associated with ultracool dwarfs. The presence of a Saturn-like planet on a circular orbit 0.3 au from a 0.06-0.08 M⊙ star represents a challenge to planet formation theory. This is the first astrometric detection of a planet at radio wavelengths.

Keywords: exoplanets; extrasolar gaseous giant planets
A Local Baseline of the Black Hole Mass Scaling Relations for Active Galaxies. IV. Correlations Between MBH and Host Galaxy σ, Stellar Mass, and Luminosity

The tight correlations between the mass of supermassive black holes (MBH) and their host-galaxy properties have been of great interest to the astrophysical community, but a clear understanding of their origin and fundamental drivers still eludes us. The local relations for active galaxies are interesting in their own right and form the foundation for any evolutionary study over cosmic time. We present Hubble Space Telescope optical imaging of a sample of 66 local active galactic nuclei (AGNs); for 14 objects, we also obtained Gemini near-infrared images. We use state-of-the-art methods to perform surface photometry of the AGN host galaxies, decomposing them into spheroid, disk, and bar (when present), and inferring the luminosity and stellar mass of the components. We combine this information with spatially resolved kinematics obtained at the Keck Telescopes to study the correlations between MBH (determined from single-epoch virial estimators) and host galaxy properties. The correlations are uniformly tight for our AGN sample, with intrinsic scatter 0.2-0.4 dex, smaller than or equal to that of quiescent galaxies. We find no difference between pseudo and classical bulges or barred and nonbarred galaxies. We show that all the tight correlations can be simultaneously satisfied by AGN hosts in the 107-109 M⊙ regime, with data of sufficient quality. The MBH-σ relation is also in agreement with that of AGN with MBH obtained from reverberation mapping, providing an indirect validation of single-epoch virial estimators of MBH.

Keywords: agn host galaxies; active galactic nuclei; supermassive black holes; scaling relations; seyfert galaxies; black hole physics; galaxy evolution
Small-scale Flux Emergence, Coronal Hole Heating, and Flux-tube Expansion: A Hybrid Solar Wind Model

Extreme-ultraviolet images from the Solar Dynamics Observatory often show loop-like fine structure to be present where no minority-polarity flux is visible in magnetograms, suggesting that the rate of ephemeral region (ER) emergence inside "unipolar" regions has been underestimated. Assuming that this rate is the same inside coronal holes as in the quiet Sun, we show that interchange reconnection between ERs and open field lines gives rise to a solar wind energy flux that exceeds 105 erg cm-2 s-1 and that scales as the field strength at the coronal base, consistent with observations. In addition to providing ohmic heating in the low corona, these reconnection events may be a source of Alfvén waves with periods ranging from the granular timescale of ∼10 minutes to the supergranular/plume timescale of many hours, with some of the longer-period waves being reflected and dissipated in the outer corona. The asymptotic wind speed depends on the radial distribution of the heating, which is largely controlled by the rate of flux-tube expansion. Along the rapidly diverging flux tubes associated with slow wind, heating is concentrated well inside the sonic point (1) because the outward conductive heat-flux density and thus the outer coronal temperatures are reduced, and (2) because the net wave energy flux is dissipated at a rate proportional to the local Alfvén speed. In this "hybrid" solar wind model, reconnection heats the lower corona and drives the mass flux, whereas waves impart energy and momentum to the outflow at greater distances.

Keywords: solar coronal holes; solar coronal heating; solar corona; solar coronal plumes; solar wind; slow solar wind; fast solar wind; solar magnetic fields; solar magnetic flux emergence; solar magnetic reconnection; alfven waves; heliosphere
Revisiting the Circumnuclear X-Ray Emission of NGC 2992 in a Historically Low State

The innermost region of the Seyfert galaxy NGC 2992 has long been suspected to be the location of intense AGN-host galaxy interaction, but photon pile up in previous high-resolution observations hampered the study of the soft X-ray excess and the interaction near its nucleus. We present an X-ray imaging and spectroscopic analysis of the circumnuclear (1″-3″) region of NGC 2992 using the zeroth-order image of a 135 ks grating observation obtained with Chandra, which captured the nucleus in a historically low flux state. Extended soft X-ray emission is detected in the circumnuclear region with an observed luminosity of L X ~ 7 × 1039 erg s-1. The majority of the previous, puzzling detection of soft excess could be associated with the outflow, indicated by the morphological correspondences between the soft X-ray emission and figure-eight-shaped radio bubbles. An anomalous narrow emission line with a centroid energy of ~4.97 keV is found. If attributed to redshifted highly ionized iron emission (e.g., Fe XXV), the required outflow velocity is ~0.23 c. An alternative explanation is that this line emission could be produced by the nuclear spallation of iron. We also find extended, asymmetric Fe Kα emission along the galactic disk, which could originate from reflection by cold gas on ~200 pc scale.

Keywords: x-ray active galactic nuclei; seyfert galaxies; galactic winds; radio lobes
The Parallax Zero-point of Gaia Early Data Release 3 from LAMOST Primary Red Clump Stars

We present an independent examination of the parallax zero-point of the Third Gaia Early Data Release (hereafter EDR3), using the LAMOST primary red clump (PRC) stellar sample. A median parallax offset of around 26 μas, slightly larger than that found by examination of distant quasars, is found for both the five- and six-parameter solutions in EDR3, based on samples of over 63,000 and 2000 PRC stars, respectively. Similar to the previous investigation of Lindegren et al., to which we compare our results, the parallax zero-point exhibits clear dependencies on the G magnitudes, colors, and positions of the objects. Based on our analysis, the zero-point of the revised parallax can be reduced to a few μas, and some significant patterns, e.g., discontinuities with stellar magnitude, can be properly removed. However, relatively large offsets (>10 μas) are still found for the revised parallaxes over different positions on the sky.

Keywords: standard candles; red giant clump; space astrometry; trigonometric parallax