adsabs/SciX_UAT_keywords huggingface dataset:
Oscillating Dark Energy in Light of the Latest Observations and Its Impact on the Hubble Tension

In this paper, we have performed a comparative study of different types of oscillating dark energy (DE) models using the Metropolis algorithm of Markov Chain Monte Carlo. Eight different oscillating parameterizations are examined herein that have demonstrated considerable ability to fit the overall cosmological observations, including the Pantheon sample of Type Ia supernovae, baryon acoustic oscillations, cosmic chronometer Hubble data, and distance priors of the Planck cosmic microwave background. In order to compare the consistency of these models with observations, we have used both the Akaike and deviance information criteria. Although the values of the Akaike information criterion for different models indicate that there is no support for oscillating DE models, the deviance information criterion showed that there is significant support for some of these models. Our results showed that these models are capable of solving the cosmic coincidence problem and alleviating the Hubble tension. Comparing the H 0 values obtained for different oscillating scenarios with that of ΛCDM, we observed that our oscillating models led to $\bar{{H}_{0}}=69.78$ , which is 0.29 greater than H 0,Λ and thus reduces the Hubble tension. Among all of the models, model 1, with H 0 = 70.00 ± 0.71, is the most capable of alleviating the H 0 tension. Furthermore, we examined our models assuming H 0 = 73.0 ± 1.4 from SHoES measurements. We find that adding this data point to our data combination led to a ${\rm{\Delta }}\bar{{H}_{0}}=0.95$ increase in the H 0 value for different models.

Keywords: cosmology; observational cosmology; cosmological models; cosmological parameters; dark energy; hubble constant
The Host Galaxy of a Dormant, Overmassive Black Hole at z = 6.7 may be Restarting Star Formation

JWST is discovering a large population of z > 4 supermassive black holes (SMBHs) that are overmassive with respect to the stellar content of their hosts. A previous study developed a physical model to interpret this overmassive population as the result of quasar feedback acting on a compact host galaxy. In this Note, we apply this model to JADES GN 1146115, a dormant SMBH at z = 6.7 whose mass is ∼40% of the host's mass in stars and accreting at ∼2% of the Eddington limit. The host has been forming stars at the low rate of ∼1 M ⊙ yr‑1 for the past ∼100 Myr. Our model suggests that this galactic system is on the verge of a resurgence of global star formation activity. This transition comes after a period of domination by the effect of its overmassive black hole, whose duration is comparable to typical quasar lifetimes.

Keywords: active galaxies; supermassive black holes; galaxy evolution; star formation; galaxy quenching
Radio-loud versus Radio-quiet Gamma-Ray Bursts: The Role of Binary Progenitors

We explore the possibility that radio-loud gamma-ray bursts (GRBs) result from the collapse of massive stars in interacting binary systems, while radio-quiet GRBs are produced by the collapse of single massive stars. A binary collapsar system can have the necessary angular momentum and energy budget to explain the longer prompt gamma-ray durations and higher isotropic energies seen in the the radio-loud subsample of long GRBs. Additionally, binary systems can lead to rich and extended circumstellar environments that allow for the presence of the long-lived radio afterglows seen in the radio-loud systems. Finally, the relative fraction of stars in binary systems versus single-star systems appears consistent with the fraction of radio-loud versus radio-quiet GRBs.

Keywords: gamma-ray bursts
Structures and Properties of Known and Postulated Interstellar Cations

Positive ions play a fundamental role in interstellar chemistry, especially in cold environments where chemistry is believed to be mainly ion driven. However, in contrast with neutral species, most of the cations present in the astrochemical reaction networks are not fully characterized in the astrochemical literature. To fill this gap, we have carried out new accurate quantum chemical calculations to identify the structures and energies of 262 cations with up to 14 atoms that are postulated to have a role in interstellar chemistry. Optimized structures and rotational constants were obtained at the M06-2X/cc-pVTZ level, while electric dipoles and total electronic energies were computed with CCSD(T)/aug-cc-pVTZ//M06-2X/cc-pVTZ single-point energy calculations. The present work complements the study by Woon & Herbst, who characterized the structure and energies of 200 neutral species also involved in interstellar chemistry. Taken together, the two data sets can be used to estimate whether a reaction, postulated in present astrochemical reaction networks, is feasible from a thermochemistry point of view and, consequently, to improve the reliability of the present networks used to simulate the interstellar chemistry. We provide an actual example of the potential use of the cations plus neutral data sets. It shows that two reactions, involving Si-bearing ions and present in the widely used reaction networks KIDA and UMIST, cannot occur in the cold interstellar medium because they are endothermic.

Keywords: astrochemistry; interstellar molecules
Hard X-Ray Excess from the Magnificent Seven Neutron Stars

We report significant hard X-ray excesses in the energy range 2-8 keV for two nearby isolated neutron stars: RX J1856.6-3754 and RX J0420.0-5022. These neutron stars have previously been observed in soft X-rays to have nearly thermal spectra at temperatures ∼100 eV, which are thought to arise from the warm neutron star surfaces. We find nontrivial hard X-ray spectra well above the thermal surface predictions with archival data from the XMM-Newton and Chandra X-ray telescopes. We analyze possible systematic effects that could generate such spurious signals, such as nearby X-ray point sources and pileup of soft X-rays, but we find that the hard X-ray excesses are robust to these systematics to the extent that is possible to test. We also investigate possible sources of hard X-ray emission from the neutron stars and find no satisfactory explanation with known mechanisms, suggesting that a novel source of X-ray emission is at play. We do not find high-significance hard X-ray excesses from the other five Magnificent Seven isolated neutron stars.

Keywords: neutron star cores; neutron stars; x-ray point sources; x-ray stars; x-ray astronomy
Physical Characterization of Metal-rich Near-Earth Asteroids 6178 (1986 DA) and 2016 ED85

Metal-rich near-Earth asteroids (NEAs) represent a small fraction of the NEA population that is mostly dominated by S- and C-type asteroids. Because of this, their identification and study provide us with a unique opportunity to learn more about the formation and evolution of this particular type of bodies, as well as their relationship with meteorites found on Earth. We present near-infrared (NIR) spectroscopic data of NEAs 6178 (1986 DA) and 2016 ED85. We found that the spectral characteristics of these objects are consistent with those of metal-rich asteroids, showing red slopes, convex shapes, and a weak pyroxene absorption band at ~0.93 μm. The compositional analysis showed that they have a pyroxene chemistry of Fs40.6±3.3Wo8.9±1.1 and a mineral abundance of ~15% pyroxene and 85% metal. We determined that these objects were likely transported to the near-Earth space via the 5:2 mean motion resonance with Jupiter. Asteroid spectra were compared with the spectra of mesosiderites and bencubbinites. Differences in the NIR spectra and pyroxene chemistry suggest that bencubbinites are not good meteorite analogs. Mesosiderites were found to have a similar pyroxene chemistry and produced a good spectral match when metal was added to the silicate component. We estimated that the amounts of Fe, Ni, Co, and the platinum group metals present in 1986 DA could exceed the reserves worldwide.

Keywords: asteroids; meteorites; spectroscopy; iron meteorites
The Araucaria Project. Distances to Nine Galaxies Based on a Statistical Analysis of their Carbon Stars (JAGB Method)

Our work presents an independent calibration of the J-region Asymptotic Giant Branch (JAGB) method using Infrared Survey Facility photometric data and a custom luminosity function profile to determine JAGB mean magnitudes for nine galaxies. We determine a mean absolute magnitude of carbon stars of MLMC = -6.212 ± 0.010 (stat.) ±0.030 (syst.) mag. We then use near-infrared photometry of a number of nearby galaxies, originally obtained by our group to determine their distances from Cepheids using the Leavitt law, in order to independently determine their distances with the JAGB method. We compare the JAGB distances obtained in this work with the Cepheid distances resulting from the same photometry and find very good agreement between the results from the two methods. The mean difference is 0.01 mag with an rms scatter of 0.06 mag after taking into account seven out of the eight analyzed galaxies that had their distances determined using Cepheids. The very accurate distance to the Small Magellanic Cloud based on detached eclipsing binaries is also in very good agreement with the distance obtained from carbon stars.

Keywords: distance indicators; galaxy distances; carbon stars; near infrared astronomy
ZTF Early Observations of Type Ia Supernovae. III. Early-time Colors As a Test for Explosion Models and Multiple Populations

Colors of Type Ia supernovae (SNe Ia) in the first few days after explosion provide a potential discriminant between different models. In this paper, we present g - r colors of 65 SNe Ia discovered within 5 days from first light by the Zwicky Transient Facility in 2018, a sample that is about three times larger than that in the literature. We find that g - r colors are intrinsically rather homogeneous at early phases, with about half of the dispersion attributable to photometric uncertainties ( ${\sigma }_{\mathrm{noise}}\sim {\sigma }_{\mathrm{int}}\,\sim $ 0.18 mag). Colors are nearly constant starting from 6 days after first light (g - r ∼ -0.15 mag), while the time evolution at earlier epochs is characterized by a continuous range of slopes, from events rapidly transitioning from redder to bluer colors (slope of ∼-0.25 mag day-1) to events with a flatter evolution. The continuum in the slope distribution is in good agreement both with models requiring some amount of 56Ni mixed in the outermost regions of the ejecta and with "double-detonation" models having thin helium layers ( ${M}_{\mathrm{He}}=0.01\,{M}_{\odot }$ ) and varying carbon-oxygen core masses. At the same time, six events show evidence for a distinctive "red bump" signature predicted by double-detonation models with larger helium masses. We finally identify a significant correlation between the early-time g - r slopes and supernova brightness, with brighter events associated to flatter color evolution (p-value = 0.006). The distribution of slopes, however, is consistent with being drawn from a single population, with no evidence for two components as claimed in the literature based on B - V colors.

Keywords: surveys; supernovae; type ia supernovae
A Study of Radio Knots within Supernova Remnant Cassiopeia A

The study on the dynamic evolution of young supernova remnants (SNRs) is an important way to understand the density structure of the progenitor's circumstellar medium. We have reported the acceleration or deceleration, proper motion, and brightness changes of 260 compact radio features in the second-youngest known SNR Cas A at 5 GHz based on the Very Large Array data of five epochs from 1987 to 2004. The radio expansion center is located at α(1950) = 23h21m9.ˢ7 ± 0.ˢ29, δ(1950) = +58°32'25.″2 ± 2.″2. Three-quarters of the compact knots are decelerating; this suggests that there are significant density fluctuations in the stellar winds of the remnant's progenitor. We have verified that the acceleration or deceleration of compact knots is not related with the distribution of brightness. The brightening, fading, disappearing, or new appearing of compact radio features in Cas A suggests that the magnetic field in the remnant is changing rapidly.

Keywords: supernova remnants; proper motions
On the Rotation of the Solar Chromosphere

Rotation is a significant characteristic of the Sun and other stars, and it plays an important role in understanding their dynamo actions and magnetic activities. In this study, the rotation of the solar chromospheric activity is investigated from a global point of view with an over 40 yr Mg II index. We determined the time-varying rotational period lengths (RPLs) with the synchrosqueezed wavelet transform, which provides high temporal and frequency resolution; furthermore, we compared the RPLs with the photospheric and coronal RPLs obtained from the sunspot numbers and the 10.7 cm radio flux data. The significance of the RPLs is taken into consideration. We found that the RPLs of the chromosphere exhibit a downward trend, as do those of the photosphere and corona; in addition, their RPLs at the recent four solar maxima also show a declining trend. This suggests that the rotation of the solar atmosphere has been accelerating during the recent four solar cycles, which is inferred to be caused by the declining strength of solar activity. The variations of the solar atmospheric RPLs show periodicities of multiple harmonics of the solar cycle period, and it is modulated by the solar activity cycle.

Keywords: solar activity; solar rotation; solar chromosphere
Cause and Kinematics of a Jetlike CME

In this article, we present the multiviewpoint and multiwavelength analysis of an atypical solar jet based on data from Solar Dynamics Observatory, SOlar and Heliospheric Observatory, and Solar TErrestrial RElations Observatory. It is generally believed that coronal mass ejections (CMEs) develop from the large-scale solar eruptions in the lower atmosphere. However, the kinematical and spatial evolution of the jet on 2013 April 28 suggests that the jet was clearly associated with a narrow CME with a width of ≈25° and speed of ≈450 km s-1. To better understand the link between the jet and the CME, we performed a coronal potential field extrapolation from the line-of-sight magnetogram of the active region. The extrapolations suggest that the jet eruption follows the same path of the open magnetic field lines from the source region, which provides a route for the jet material to escape from the solar surface toward the outer corona.

Keywords: solar magnetic fields; solar activity; the sun; solar coronal mass ejections
Dust Attenuation Curves at z ∼ 0.8 from LEGA-C: Precise Constraints on the Slope and 2175ŠBump Strength

We present a novel approach to measure the attenuation curves of 485 individual star-forming galaxies with ${M}_{* }$ > 1010 M⊙ based on deep optical spectra from the VLT/VIMOS LEGA-C survey and multiband photometry in the COSMOS field. Most importantly, we find that the attenuation curves in the rest-frame 3000-4500 Å range are typically almost twice as steep as the Milky Way, LMC, SMC, and Calzetti attenuation curves, which is in agreement with recent studies of the integrated light of present-day galaxies. The attenuation at 4500 Å and the slope strongly correlate with the galaxy inclination: face-on galaxies show less attenuation and steeper curves compared to edge-on galaxies, suggesting that geometric effects dominate observed variations in attenuation. Our new method produces 2175 Å UV bump detections for 260 individual galaxies. Even though obvious correlations between UV bump strength and global galaxy properties are absent, strong UV bumps are most often seen in face-on, lower-mass galaxies (10 < log10(M*/M⊙) < 10.5) with low overall attenuation. Finally, we produce a typical attenuation curve for star-forming galaxies at z ∼ 0.8; this prescription represents the effect of dust on the integrated spectral energy distributions of high-redshift galaxies more accurately than commonly used attenuation laws.

Keywords: interstellar dust extinction
Dissecting the Different Components of the Modest Accretion Bursts of the Very Young Protostar HOPS 373

Observed changes in protostellar brightness can be complicated to interpret. In our James Clerk Maxwell Telescope (JCMT) Transient Monitoring Survey, we discovered that a young binary protostar, HOPS 373, is undergoing a modest 30% brightness increase at 850 μm, caused by a factor of 1.8-3.3 enhancement in the accretion rate. The initial burst occurred over a few months, with a sharp rise and then a shallower decay. A second rise occurred soon after the decay, and the source is still bright one year later. The mid-IR emission, the small-scale CO outflow mapped with ALMA, and the location of variable maser emission indicate that the variability is associated with the SW component. The near-IR and NEOWISE W1 and W2 emission is located along the blueshifted CO outflow, spatially offset by ~3 to 4″ from the SW component. The K-band emission imaged by UKIRT shows a compact H2 emission source at the edge of the outflow, with a tail tracing the outflow back to the source. The W1 emission, likely dominated by scattered light, brightens by 0.7 mag, consistent with expectations based on the submillimeter light curve. The signal of continuum variability in K band and W2 is masked by stable H2 emission, as seen in our Gemini/GNIRS spectrum, and perhaps by CO emission. These differences in emission sources complicate IR searches for variability of the youngest protostars.

Keywords: stellar jets; variable stars; stellar accretion disks; submillimeter astronomy; protostars
Suprathermal Ion Energy Spectra and Anisotropies near the Heliospheric Current Sheet Crossing Observed by the Parker Solar Probe during Encounter 7

We present observations of ≳10-100 keV nucleon-1 suprathermal (ST) H, He, O, and Fe ions associated with crossings of the heliospheric current sheet (HCS) at radial distances of <0.1 au from the Sun. Our key findings are as follows: (1) very few heavy ions are detected during the first full crossing, the heavy-ion intensities are reduced during the second partial crossing and peak just after the second crossing; (2) ion arrival times exhibit no velocity dispersion; (3) He pitch-angle distributions track the magnetic field polarity reversal and show up to ~10:1 anti-sunward, field-aligned flows and beams closer to the HCS that become nearly isotropic farther from the HCS; (4) the He spectrum steepens either side of the HCS, and the He, O, and Fe spectra exhibit power laws of the form ~E -4-E 6; and (5) maximum energies E X increase with the ion's charge-to-mass (Q/M) ratio as ${E}_{X}/{E}_{H}\propto {({Q}_{X}/{M}_{X})}^{\delta }$ , where δ ~ 0.65-0.76, assuming that the average Q states are similar to those measured in gradual and impulsive solar energetic particle events at 1 au. The absence of velocity dispersion in combination with strong field-aligned anisotropies closer to the HCS appears to rule out solar flares and near-Sun coronal-mass-ejection-driven shocks. These new observations present challenges not only for mechanisms that employ direct parallel electric fields and organize maximum energies according to E/Q but also for local diffusive and magnetic-reconnection-driven acceleration models. Reevaluation of our current understanding of the production and transport of energetic ions is necessary to understand this near-solar, current-sheet-associated population of ST ions.

Keywords: the sun; solar magnetic reconnection; interplanetary particle acceleration; interplanetary magnetic fields; heliosphere
Multiphase Gas Flows in the Nearby Seyfert Galaxy ESO428-G014. Paper I

We present ALMA 230 GHz continuum and CO(2-1) observations of the nearby Compton-thick Seyfert galaxy ESO428-G14, with angular resolution 0"7 (78 pc). CO(2-1) is distributed in clumpy spiral arms, a lopsided circumnuclear ring (CNR) with ∼200 pc radius, and a transverse gas lane with size <100 pc, which crosses the nucleus and connects the two portions of the CNR. The main CO velocity gradient is consistent with a rotating disk with dynamical mass Mdyn = 5 × 109 M⊙ within ∼1 kpc. We detect off-plane gas motions with respect to the main disk plane which likely trace a molecular outflow with rate ${\dot{M}}_{\mathrm{of}}\approx 0.1\mbox{--}0.3\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ , along a biconical structure with radius 700 pc. The CO outflow smoothly joins the warm molecular outflow detected in SINFONI/Very Large Telescope data in the central 170 pc, suggesting that the outflow may cool with increasing distance. Our dynamical modeling of the inner 100 pc region suggests a warped disk or bar, and of fast gas streams which may trace an inflow toward the AGN. The inner warped disk overlaps with the most obscured, CT region seen in X-rays. There, we derive a column density $N({{\rm{H}}}_{2})\approx 2\times {10}^{23}\,{\mathrm{cm}}^{-2}$ , suggesting that molecular gas may contribute significantly to the AGN obscuration. Most of the hard X-ray emitting nuclear region is deprived of cold molecular gas and shows a CO-cavity. The CO-cavity is filled with warm molecular gas traced by H2, confirming that the 3-6 keV continuum and Fe Kα emission are due to scattering from dense ISM clouds.

Keywords: agn host galaxies; active galactic nuclei; interstellar medium; galaxy kinematics
Belatedly Habitable Planets

Stars do not remain static, so their habitable zones evolve in time. Over a star's evolution, its habitable zone encompasses new planets, and it remains uncertain whether these planets can become habitable. We refer to this often overlooked class of planets as lying in the belatedly habitable zone, and stress that many planets found in the habitable zones of other stars will belong to this class. Future studies should take belated habitability into account and not implicitly assume that these planets are habitable.

Keywords: exoplanets; exoplanet evolution; exoplanet astronomy; astrobiology; habitable zone; habitable planets
On-disk Solar Coronal Condensations Facilitated by Magnetic Reconnection between Open and Closed Magnetic Structures

Coronal condensation and rain are a crucial part of the mass cycle between the corona and chromosphere. In some cases, condensation and subsequent rain originate in the magnetic dips formed during magnetic reconnection. This provides a new and alternative formation mechanism for coronal rain. Until now, only off-limb, rather than on-disk, condensation events during reconnection have been reported. In this paper, employing extreme-ultraviolet (EUV) images of the Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory (SDO), we investigate the condensations facilitated by reconnection from 2011 July 14-15, when STEREO was in quadrature with respect to the Sun-Earth line. Above the limb, in STEREO/EUV Imager (EUVI) 171 Å images, higher-lying open structures move downward, reconnect with the lower-lying closed loops, and form dips. Two sets of newly reconnected structures then form. In the dips, bright condensations occur in the EUVI 304 Å images repeatedly, which then flow downward to the surface. In the on-disk observations by SDO/Atmospheric Imaging Assembly (AIA) in the 171 Å channel, these magnetic structures are difficult to identify. Dark condensations appear in the AIA 304 Å images, and then move to the surface as on-disk coronal rain. The cooling and condensation of coronal plasma is revealed by the EUV light curves. If only the on-disk observations were be available, the relation between the condensations and reconnection, shown clearly by the off-limb observations, could not be identified. Thus, we suggest that some on-disk condensation events seen in transition region and chromospheric lines may be facilitated by reconnection.

Keywords: solar magnetic reconnection; plasma physics; solar corona; solar ultraviolet emission; solar magnetic fields