adsabs/SciX_UAT_keywords huggingface dataset:
Bistability of the Atmospheric Circulation on TRAPPIST-1e

Using a 3D general circulation model, we demonstrate that a confirmed rocky exoplanet and a primary observational target, TRAPPIST-1e presents an interesting case of climate bistability. We find that the atmospheric circulation on TRAPPIST-1e can exist in two distinct regimes for a 1 bar nitrogen-dominated atmosphere. One is characterized by a single strong equatorial prograde jet and a large day-night temperature difference; the other is characterized by a pair of mid-latitude prograde jets and a relatively small day-night contrast. The circulation regime appears to be highly sensitive to the model setup, including initial and surface boundary conditions, as well as physical parameterizations of convection and cloud radiative effects. We focus on the emergence of the atmospheric circulation during the early stages of simulations and show that the regime bistability is associated with a delicate balance between the zonally asymmetric heating, mean overturning circulation, and mid-latitude baroclinic instability. The relative strength of these processes places the GCM simulations on different branches of the evolution of atmospheric dynamics. The resulting steady states of the two regimes have consistent differences in the amount of water content and clouds, affecting the water absorption bands as well as the continuum level in the transmission spectrum, although they are too small to be detected with current technology. Nevertheless, this regime bistability affects the surface temperature, especially on the night side of the planet, and presents an interesting case for understanding atmospheric dynamics and highlights uncertainty in 3D GCM results, motivating more multimodel studies.

Keywords: exoplanet atmospheres; planetary atmospheres; habitable planets; habitable zone; water vapor; atmospheric circulation; transmission spectroscopy; theoretical models
Demographics of Triple Systems in Dense Star Clusters

Depending on the stellar type, more than 15% of stars in the field have at least two stellar companions. Hierarchical triple systems can be assembled dynamically in dense star clusters, as a result of few-body encounters among stars and/or compact remnants in the cluster core. In this paper, we present the demographics of stellar and compact-object triples formed via binary-binary encounters in the CMC Cluster Catalog, a suite of cluster simulations with present-day properties representative of the globular clusters (GCs) observed in the Milky Way. We show how the initial properties of the host cluster set the typical orbital parameters and formation times of the formed triples. We find that a cluster typically assembles hundreds of triples with at least one black hole (BH) in the inner binary, while only clusters with sufficiently small virial radii are efficient in producing triples with no BHs. We show that a typical GC is expected to host tens of triples with at least one luminous component at present. We discuss how the Lidov-Kozai mechanism can drive the inner binary of these dynamically formed triples to high eccentricities, whenever it takes place before the triple is dynamically reprocessed by encountering another cluster member. Some of these systems can reach sufficiently large eccentricities to form a variety of transients and merger products, such as blue stragglers, X-ray binaries, Type Ia supernovae, Thorne-Zytkow objects, and gravitational wave sources.

Keywords: astrophysical black holes; gravitational waves; stellar mass black holes; globular star clusters; star clusters; trinary stars; neutron stars; gravitational wave astronomy; galaxy clusters; milky way dynamics; blue straggler stars
Bump Morphology of the CMAGIC Diagram

We apply the color-magnitude intercept calibration method (CMAGIC) to the Nearby Supernova Factory SNe Ia spectrophotometric data set. The currently existing CMAGIC parameters are the slope and intercept of a straight line fit to the linear region in the color-magnitude diagram, which occurs over a span of approximately 30 days after maximum brightness. We define a new parameter, ω XY , the size of the "bump" feature near maximum brightness for arbitrary filters X and Y. We find a significant correlation between the slope of the linear region, β XY , in the CMAGIC diagram and ω XY . These results may be used to our advantage, as they are less affected by extinction than parameters defined as a function of time. Additionally, ω XY is computed independently of templates. We find that current empirical templates are successful at reproducing the features described in this work, particularly SALT3, which correctly exhibits the negative correlation between slope and "bump" size seen in our data. In 1D simulations, we show that the correlation between the size of the "bump" feature and β XY can be understood as a result of chemical mixing due to large-scale Rayleigh-Taylor instabilities.

Keywords: supernovae; type ia supernovae; photometry; spectrophotometry
Exploration of Aspherical Ejecta Properties in Type Ia Supernovae: Progenitor Dependence and Applications to Progenitor Classification

Several explosions of type Ia supernovae (SNe Ia) have been found to exhibit deviations from spherical symmetry upon closer inspection. Examples are the gamma-ray lines from SN 2014J as measured by INTEGRAL/SPI and morphology information from radioactive isotopes in older remnants such as Tycho. A systematic study of the effects of parameters such as ignition geometry and burning morphology in SNe Ia is still missing. We use a two-dimensional hydrodynamics code with postprocessing nucleosynthesis and simulate the double detonations in a sub-Chandrasekhar-mass carbon-oxygen white dwarf starting from the nuclear runaway in the accumulated He envelope toward disruption of the white dwarf. We explore potential variety through four triggering scenarios that sample main asymmetry drivers. We further investigate their global effects on the aspherical structure of the ejecta based on individual elements. We apply the results to the well-observed SN 2014J and other recently observed SN remnants in order to illustrate how these new observational data, together with other observed quantities, help to constrain the explosion and progenitors of SNe Ia.

Keywords: type ia supernovae; hydrodynamical simulations; gamma-rays; chemical abundances; explosive nucleosynthesis; supernova remnants
Improvement of Pan-STARRS Photometric Calibration with LAMOST and Gaia

In this work, we perform the recalibration of Pan-STARRS1 (PS1) photometry by correcting for position-dependent systematic errors using the spectroscopy-based stellar color regression (SCR) method, the photometry-based SCR method, and the Gaia BP/RP synthetic photometry method. We confirm the significant large-scale and small-scale spatial variation of the magnitude offsets for all the grizy filters. We show that the PS1 photometric calibration precisions in the grizy filters are around 5-7 mmag when averaged over 14' regions. We note a much larger calibration error up to 0.04 mag in the Galactic plane, which is probably caused by the systematic errors of the PS1 magnitudes in crowded fields. The results of the three methods are consistent with each other within 1-2 mmag or better for all the filters. We provide 2D maps and a Python package to correct for position-dependent magnitude offsets of PS1, which can be used for high-precision investigations and as a reference to calibrate other surveys.

Keywords: stellar photometry; astronomy data analysis; calibration
Analysis of a JWST NIRSpec Lab Time Series: Characterizing Systematics, Recovering Exoplanet Transit Spectroscopy, and Constraining a Noise Floor

The James Webb Space Telescope's (JWST) NIRSpec instrument will unveil the nature of exoplanet atmospheres across the wealth of planet types, from temperate terrestrial worlds to ultrahot Jupiters. In particular, the 0.6-5.3 μm PRISM mode is especially well suited for efficient spectroscopic exoplanet observations spanning a number of important spectral features. We analyze a lab-measured NIRSpec PRISM mode Bright Object Time Series observation from the perspective of a JWST user to understand the instrument performance and detector properties. We create two realistic transiting exoplanet time-series observations by performing injection-recovery tests on the lab-measured data to quantify the effects of real instrument jitter, drift, intrapixel sensitivity variations, and 1/f noise on measured transmission spectra. By fitting the time-series systematics simultaneously with the injected transit, we can obtain more realistic transit-depth uncertainties that take into account noise sources that are currently not modeled by traditional exposure time calculators. We find that sources of systematic noise related to intrapixel sensitivity variations and point-spread function motions are apparent in the data at the level of a few hundred ppm but can be effectively detrended using a low-order polynomial with detector position. We recover the injected spectral features of GJ 436 b and TRAPPIST-1 d and place a 3σ upper limit on the detector noise floor of 14 ppm. We find that the noise floor is consistent with <10 ppm at the 1.7σ level, which bodes well for future observations of challenging targets with faint atmospheric signatures.

Keywords: exoplanet atmospheres; transmission spectroscopy; space telescopes
Spatially Resolved Molecular Interstellar Medium in a z = 6.6 Quasar Host Galaxy

We present high spatial resolution (~0.″4, 2.2 kpc) observations of the CO(6-5), CO(7-6), and [C I]369 μm lines and dust continuum emission from the interstellar medium (ISM) in the host galaxy of the quasar J0305-3150 at z = 6.6. These, together with archival [C II]158 μm data at a comparable spatial resolution, enable studies of the spatial distribution and kinematics between the ISM in different phases. When comparing the radial profiles of CO, [C II]158 μm, and the dust continuum, we find that the CO and dust continuum exhibit similar spatial distributions, both of which are less extended than the [C II]158 μm, indicating that the CO and dust continuum are tracing the same gas component, while the [C II]158 μm is tracing a more extended one. In addition, we derive the radial profiles of the [C II]158 μm/CO, [C II]158 μm/far-infrared (FIR), CO/FIR, and dust continuum S 98.7 GHz/S 258.1 GHz ratios. We find a decreasing S 98.7 GHz/S 258.1 GHz ratio with radius, possibly indicating a decrease of dust optical depth with increasing radius. We also detect some of the ISM lines and continuum emission in the companion galaxies previously discovered in the field around J0305-3150. Through comparing the line-to-line and line-to-FIR ratios, we find no significant differences between the quasar and its companion galaxies.

Keywords: interstellar medium; quasars; submillimeter astronomy; agn host galaxies; interstellar dust; high-redshift galaxies; early universe; molecular gas; interstellar atomic gas
The Extremely Buried Nucleus of IRAS 17208-0014 Observed at Submillimeter and Near-infrared Wavelengths

The ultraluminous infrared galaxy IRAS 17208-0014 is a late-stage merger that hosts a buried active galactic nucleus (AGN). To investigate its nuclear structure, we performed high-spatial-resolution ( ~ 0.″04 ~ 32 pc) Atacama Large Millimeter/submillimeter Array (ALMA) observations in Band 9 (~450 μm or ~660 GHz), along with near-infrared AKARI spectroscopy in 2.5-5.0 μm. The Band 9 dust continuum peaks at the AGN location, and toward this position CO(J = 6 - 5) and CS(J = 14 - 13) are detected in absorption. Comparison with nonlocal thermal equilibrium calculations indicates that, within the central beam (r ~ 20 pc), there exists a concentrated component that is dense (107 cm-3) and warm (>200 K) and has a large column density ( ${N}_{{{\rm{H}}}_{2}}\gt {10}^{23}\,{\mathrm{cm}}^{-2}$ ). The AKARI spectrum shows deep and broad CO rovibrational absorption at 4.67 μm. Its band profile is well reproduced with a similarly dense and large column but hotter (~1000 K) gas. The region observed through absorption in the near-infrared is highly likely in the nuclear direction, as in the submillimeter, but with a narrower beam including a region closer to the nucleus. The central component is considered to possess a hot structure where vibrationally excited HCN emission originates. The most plausible heating source for the gas is X-rays from the AGN. The AKARI spectrum does not show other AGN signs in 2.5-4 μm, but this absence may be usual for AGNs buried in a hot mid-infrared core. Further, based on our ALMA observations, we relate the various nuclear structures of IRAS 17208-0014 that have been proposed in the literature.

Keywords: ultraluminous infrared galaxies; active galactic nuclei; galaxy mergers; interferometry; spectroscopy
High-resolution Emission Spectroscopy of the Ultrahot Jupiter KELT-9b: Little Variation in Day- and Nightside Emission Line Contrasts

The transmission spectrum of the ultrahot Jupiter KELT-9b (T eq ~ 4000 K) exhibits absorption by several metal species. We searched for atomic and molecular lines in its emission spectrum by observing partial phase curves with the Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs (R ~ 80,000-95,000). We find evidence for emission by Si I in the atmosphere of KELT-9b for the first time. Additionally we find evidence for emission by Mg I and Ca II, which were previously detected in transmission, and confirmed earlier detections of Fe I emission. Conversely, we find no evidence for dayside emission from Al I, Ca I, Cr I, FeH, Fe II, K I, Li I, Mg II, Na I, OH, Ti I, TiO, V I, V II, VO, and Y I. By employing likelihood mapping, we find indications of there being little variation in emission line contrast between the day- and nightsides-suggesting that KELT-9b may harbor iron emission on its nightside. Our results demonstrate that high-resolution ground-based emission spectroscopy can provide valuable insights into exoplanet atmospheres.

Keywords: exoplanet atmospheres; planetary atmospheres; extrasolar gaseous giant planets; exoplanets; hot jupiters; exoplanet atmospheric composition
Spectral Features of the Solar Transition Region and Chromospheric Lines at Flare Ribbons Observed with IRIS

We report on the spectral features of the Si IV λ1402.77, C II λ1334.53, and Mg II h or k lines, formed in the layers from the transition region to the chromosphere, in three two-ribbon flares (with X, M, and C class) observed with IRIS. All three lines show significant redshifts within the main flare ribbons, which mainly originate from the chromospheric condensation during the flares. The average redshift velocities of the Si IV line within the main ribbons are 56.6, 25.6, and 10.5 km s-1 for the X-, M-, and C-class flares, respectively, which show a decreasing tendency with the flare class. The C II and Mg II lines show a similar tendency but with smaller velocities compared to the Si IV line. Additionally, the Mg II h or k line shows a blue-wing enhancement in the three flares, in particular at the flare ribbon fronts, which is supposed to be caused by an upflow in the upper chromosphere due to the heating of the atmosphere. Moreover, the Mg II h or k line exhibits a central reversal at the flare ribbons but turns to pure emission shortly after 1-4 minutes. Correspondingly, the C II line also shows a central reversal but in a smaller region. However, for the Si IV line, the central reversal is only found in the X-class flare. As usual, the central reversal of these lines can be caused by the opacity effect. This implies that, in addition to the optically thick lines (C II and Mg II lines), the Si IV line can become optically thick in a strong flare, which is likely related to the nonthermal electron beam heating.

Keywords: solar activity; solar flares; solar transition region; solar chromosphere; solar ultraviolet emission; solar flare spectra
Dynamics Evolution of a Solar Active-region Filament from a Quasi-static State to Eruption: Rolling Motion, Untwisting Motion, Material Transfer, and Chirality

To better understand the magnetic structure and eruptive process of solar filaments, a solar active-region filament (labeled F2) eruption associated with a B-class flare was investigated by using high-resolution Hα data from the 1 m New Vacuum Solar Telescope (NVST), combined with EUV observations of the Solar Dynamics Observatory (SDO). The filament F2 was disturbed by another filament (labeled F1) eruption that experienced a whip-like motion. Before the filament F2 eruption, the Dopplergrams show that the southern and the northern parts of the filament F2 body exhibit blueshift and redshift along the filament spine, simultaneously. This implies that the filament F2 was rolling from one side to the other. During the filament F2 eruption, the Doppler shifts of the filament body are opposite of those before its eruption. This demonstrates that the filament body exhibits an untwisting motion, which can also be identified by tracing the movement of the eruptive filament threads. Moreover, it is found that the material of the filament F2 was transferred to the surrounding magnetic field loops, which is caused by magnetic reconnection between the filament F2 and the surrounding magnetic loops. According to the right-bearing threads of the filament F2 before its eruption, it can be deduced that the filament F2 is initially supported by a sheared arcade. The following observations reveal that the twisted magnetic structure of filament F2 formed in the eruption phase.

Keywords: solar filament eruptions; solar filaments; solar flares; sunspots; magnetic fields; active solar chromosphere; solar chromosphere; solar atmosphere
COSMOS-Web: Intrinsically Luminous z ≳ 10 Galaxy Candidates Test Early Stellar Mass Assembly

We report the discovery of 15 exceptionally luminous 10 ≲ z ≲ 14 candidate galaxies discovered in the first 0.28 deg2 of JWST/NIRCam imaging from the COSMOS-Web survey. These sources span rest-frame UV magnitudes of ‑20.5 > M UV > ‑22, and thus constitute the most intrinsically luminous z ≳ 10 candidates identified by JWST to date. Selected via NIRCam imaging, deep ground-based observations corroborate their detection and help significantly constrain their photometric redshifts. We analyze their spectral energy distributions using multiple open-source codes and evaluate the probability of low-redshift solutions; we conclude that 12/15 (80%) are likely genuine z ≳ 10 sources and 3/15 (20%) likely low-redshift contaminants. Three of our z ∼ 12 candidates push the limits of early stellar mass assembly: they have estimated stellar masses ∼ 5 × 109 M ⊙, implying an effective stellar baryon fraction of ϵ ⋆ ∼ 0.2‑0.5, where ϵ ⋆ ≡ M ⋆/(f b M halo). The assembly of such stellar reservoirs is made possible due to rapid, burst-driven star formation on timescales < 100 Myr where the star formation rate may far outpace the growth of the underlying dark matter halos. This is supported by the similar volume densities inferred for M ⋆ ∼ 1010 M ⊙ galaxies relative to M ⋆ ∼ 109 M ⊙—both about 10‑6 Mpc‑3—implying they live in halos of comparable mass. At such high redshifts, the duty cycle for starbursts would be of order unity, which could cause the observed change in the shape of the UV luminosity function from a double power law to a Schechter function at z ≈ 8. Spectroscopic redshift confirmation and ensuing constraints of their masses will be critical to understand how, and if, such early massive galaxies push the limits of galaxy formation in the Lambda cold dark matter paradigm.

Keywords: reionization; high-redshift galaxies; redshift surveys; lyman-break galaxies
The Neon Gap: Probing Ionization with Dwarf Galaxies at z 1

We present measurements of [NeIII]λ3869 emission in z ~ 1 low-mass galaxies taken from the Keck/DEIMOS spectroscopic surveys HALO7D and DEEPwinds. We identify 167 individual galaxies with significant [NeIII] emission lines, including 112 "dwarf" galaxies with $\mathrm{log}({M}_{\star }/{M}_{\odot })\lt \,9.5$ , with 0.3 < z < 1.4. We also measure [NeIII] emission from composite spectra derived from all [OII]λλ3727,3729 line emitters in this range. This provides a unique sample of [NeIII] emitters between well-studied emitters at z = 0 and 2 < z < 3. To study evolution in ionization conditions in the interstellar medium (ISM) over this time, we analyze the log([NeIII]λ3869/[OII]λλ3727,3729) ratio (Ne3O2) as a function of the stellar mass and of the log([OIII]λλ4959,5007/[OII]λλ3727,3729) ratio (O32). We find that the typical star-forming dwarf galaxy at this redshift, as measured from the composite spectra, shares the Ne3O2-M ⋆ relation with local galaxies but has higher O32 at a given Ne3O2. This finding implies that the ionization and metallicity characteristics of the z ~ 1 dwarf population do not evolve substantially from z ~ 1 to z = 0, suggesting that the known evolution in those parameters from z ~ 2 has largely taken place by z ~ 1. Individual [NeIII]-detected galaxies have emission characteristics situated between local and z ~ 2 galaxies, with elevated Ne3O2 and O32 emission potentially explained by variations in stellar and nebular metallicity. We also compare our dwarf sample to similarly low-mass z > 7 galaxies identified in JWST Early Release Observations, finding four HALO7D dwarfs with similar size, metallicity, and star formation properties.

Keywords: emission line galaxies; interstellar medium; dwarf galaxies; metallicity; photoionization
ALMA CO Observations of Gamma-Ray Supernova Remnant N132D in the Large Magellanic Cloud: Possible Evidence for Shocked Molecular Clouds Illuminated by Cosmic-Ray Protons

N132D is the brightest gamma-ray supernova remnant (SNR) in the Large Magellanic Cloud (LMC). We carried out 12CO(J = 1-0, 3-2) observations toward the SNR using the Atacama Large Millimeter/submillimeter Array (ALMA) and Atacama Submillimeter Telescope Experiment. We find diffuse CO emission not only at the southern edge of the SNR as previously known, but also inside the X-ray shell. We spatially resolved nine molecular clouds using ALMA with an angular resolution of 5″, corresponding to a spatial resolution of ∼1 pc at the distance of the LMC. Typical cloud sizes and masses are ∼2.0 pc and ∼100 M⊙, respectively. High intensity ratios of CO J = 3-2/1-0 > 1.5 are seen toward the molecular clouds, indicating that shock heating has occurred. Spatially resolved X-ray spectroscopy reveals that thermal X-rays in the center of N132D are produced not only behind a molecular cloud but also in front of it. Considering the absence of a thermal component associated with the forward shock toward one molecular cloud located along the line of sight to the center of the remnant, this suggests that this particular cloud is engulfed by shock waves and is positioned on the near side of the remnant. If the hadronic process is the dominant contributor to the gamma-ray emission, the shock-engulfed clouds play a role as targets for cosmic rays. We estimate the total energy of cosmic-ray protons accelerated in N132D to be ∼0.5-3.8 × 1049 erg as a conservative lower limit, which is similar to that observed in Galactic gamma-ray SNRs.

Keywords: supernova remnants; interstellar medium; cosmic ray sources; gamma-ray sources; x-ray sources; large magellanic cloud