Sazuna/UAT_keywords huggingface dataset:
High-resolution Transmission Spectra of Earth Through Geological Time. The next generation of ground- and space-based telescopes will be able to observe rocky Earth-like planets in the near future, transiting their host star. We explore how the transmission spectrum of Earth changed through its geological history. These transmission spectra provide a template for how to characterize an Earth-like exoplanet—from a young prebiotic world to a modern Earth. They also allow us to explore at what point in its evolution a distant observer could identify life on our Pale Blue Dots and other worlds like it. We chose atmosphere models representative of five geological epochs of Earth's history, corresponding to a prebiotic high CO2-world 3.9 billion years ago (Ga), an anoxic world around 3.5 Ga, and 3 epochs through the rise of oxygen from 0.2% to present atmospheric levels of 21%. Our transmission spectra show atmospheric spectral features, which would show a remote observer that Earth had a biosphere since about 2 billion years ago. The high-resolution transmission spectral database of Earth through geological time from the VIS to the IR is available online and can be used as a tool to optimize our observation strategy, train retrieval methods, and interpret upcoming observations with the James Webb Space Telescope, the Extremely Large Telescopes, and future mission concepts like Origins, HabEx, and LUOVIR.

Keywords: High resolution spectroscopy, Exoplanets, Molecular spectroscopy, Exoplanet astronomy, Spectroscopy, Exoplanet atmospheres
ALMA 50-parsec-resolution Imaging of Jet-ISM Interaction in the Lensed Quasar MG J0414+0534. We report our high-resolution (0.03 arcsec-0.07 arcsec) Atacama Large Millimeter/submillimeter Array (ALMA) imaging of the quadruply lensed radio-loud quasar MG J0414+0534 at redshift z = 2.639 in the continuum and the broad CO(11-10) line at ∼340 GHz. With the help of strong lensing magnification and ALMA's high resolution, we succeeded in resolving the jet/dust and CO gas in the quasar host galaxy, both extending up to ∼1 kpc, with a resolution of ∼50 pc for the first time. Both the continuum emission and the CO(11-10) line have a similar bimodal structure aligned with the quasar jets (∼200 pc) observed by Very Long Baseline Interferometry at 5 and 8.4 GHz. The CO gas in the vicinity of both the eastern and western jet components at the location of ∼80 pc from the quasar core are moving at high velocities, up to ±600 km s-1 relative to the core. The observed features show clear evidence of strong interaction between the jets and interstellar medium (ISM). High temperature and high-density environments in the ISM of the quasar host galaxy, as suggested from CO line ratios, also support this result. The small scale of the jets, the jet-ISM interaction, and the continuum spectral energy distribution of this source indicate that we are watching the infancy stage of quasar radio activity.

Keywords: Radio jets, Strong gravitational lensing, Molecular clouds, Radio loud quasars, Interstellar medium
Planet-induced Vortices with Dust Coagulation in Protoplanetary Disks. In this work, we study how the dust coagulation/fragmentation will influence the evolution and observational appearances of vortices induced by a massive planet embedded in a low-viscosity disk by performing global 2D high-resolution hydrodynamical simulations. Within the vortex, due to its higher gas surface density and steeper pressure gradients, dust coagulation, fragmentation, and drift (to the vortex center) are all quite efficient, producing dust particles ranging from 1 μm to ∼1.0 cm, as well as an overall high dust-to-gas ratio (above unity). In addition, the dust size distribution is quite nonuniform inside the vortex, with the mass-weighted average dust size at the vortex center (∼4.0 mm) being a factor of ∼10 larger than other vortex regions. Both large (∼millimeter) and small (tens of microns) particles contribute strongly to affect the gas motion within the vortex. As such, we find that the inclusion of dust coagulation has a significant impact on the vortex lifetime and the typical vortex lifetime is about 1000 orbits. After the initial gaseous vortex is destroyed, the dust spreads into a ring with a few remaining smaller gaseous vortices with a high dust concentration and a large maximum size (∼millimeter). At late time, the synthetic dust continuum images for the coagulation case show as a ring inlaid with several hot spots at the 1.33 mm band, while only distinct hot spots remain at 7.0 mm.

Keywords: Gas-to-dust ratio, Hydrodynamical simulations, Exoplanets, Dust continuum emission, Protoplanetary disks, Planet formation
SDSS-IV MaNGA: Kinematic Asymmetry as an Indicator of Galaxy Interaction in Paired Galaxies. The interaction between galaxies is believed to be the main origin of the peculiarities of galaxies, which disturbs not only the morphology but also their kinematics. These disturbed and asymmetric features are the indicators of galaxy interaction. We study the velocity field of the ionized gas of the paired galaxies in the SDSS-IV MaNGA IFU survey. Using the kinemetry package, we fit the velocity field of the ionized gas to quantify the degree of kinematic asymmetry. We find that the star formation rate (SFR) of the paired galaxies with high kinematic asymmetry is significantly enhanced even when the projected separation between the pair members is quite large (dp ∼ 100 h-1 kpc. On the contrary, no significant SFR enhancement is found for the paired galaxies with low kinematic asymmetry even when their projected separation is small (dp &lt; 30 h-1 kpc). Moreover, we also find that the fraction of galaxies with high kinematic asymmetry is much higher in close pairs (dp &lt; 30 h-1 kpc) than those with larger d&lt;SUB&lt;p, which explains well the early statistical finding of the significant SFR enhancement in close pairs. Our new findings illustrate that the kinematic asymmetry is an excellent indicator of galaxy-galaxy interaction strength, which helps us better understand the merging stage of the observed galaxy pairs.

Keywords: Galaxy pairs, Star formation, Galaxy mergers, Galaxy kinematics, Interacting galaxies
A Well-aligned Orbit for the 45 Myr-old Transiting Neptune DS Tuc Ab. DS Tuc Ab is a Neptune-sized planet that orbits around a G star in the 45 Myr old Tucana-Horologium moving group. Here, we report the measurement of the sky-projected angle between the stellar spin axis and the planet's orbital axis, based on the observation of the Rossiter-McLaughlin effect during three separate planetary transits. The orbit appears to be well aligned with the equator of the host star, with a projected obliquity of λ = 2.5-0.9+1.0°. In addition to the distortions in the stellar absorption lines due to the transiting planet, we observed variations that we attribute to large starspots, with angular sizes of tens of degrees. The technique that we have developed for simultaneous modeling of starspots and the planet-induced distortions may be useful in other observations of planets around active stars.

Keywords: Exoplanet dynamics, Exoplanet evolution, Stellar associations
Mass-shedding Activities of Asteroid (3200) Phaethon Enhanced by Its Rotation. Asteroid (3200) Phaethon, a B-type asteroid, has been active during its perihelion passages. This asteroid is considered to be a source of the Geminid meteor stream. It is reported that this asteroid is spinning at a rotation period of 3.60 hr and has a top shape (an oblate body with an equatorial ridge) with a mean equatorial diameter of 6.25 km. Here, we report that Phaethon's rotation state may be close to or above its critical rotation period when the bulk density is 0.5-1.5 g cm-3 (a typical bulk density of a B-type asteroid). We found that in this condition, the structure of Phaethon is sensitive to failure unless the cohesive strength is ∼ 50 - ∼ 260 Pa. This result implies that if there are some surface processes driven by, for example, thermal waves, large-scaled deformation may happen and cause mass shedding. From this interpretation, we propose the processes that produced the Geminid meteor stream in the past and dust tails recently. Phaethon initially rotated at a spin period shorter than the current period. The magnitude of structural deformation at this stage was higher than the present spin condition, and a large mass-shedding event, I.e., the Geminid meteor stream, occurred. After this deformation process, the body became more oblate, and its spin slowed down. At this point, while the spin was high enough for the body to have mass-shedding events, the magnitude of these events became small.

Keywords: Near-Earth objects, Planetary surfaces, Asteroids, Meteor streams, Planetary science, Meteors, Planetary structure
CO, Water, and Tentative Methanol in η Carinae Approaching Periastron. The complex circumstellar environment around the massive binary and luminous blue variable η Carinae is known to harbor numerous light molecules, emitting most strongly in rotational states with upper level energies to ∼300 K. In circumstellar gas, the complex organic molecule methanol (CH3OH) has been found almost exclusively around young stellar objects, and thus regarded as a signpost of recent star formation. Here we report the first potential detection of methanol around a highly evolved high-mass star, while using the Atacama Large Millimeter Array to investigate molecular cloud conditions traced by CO (2-1) in an orbit phase preceding the 2020 periastron. The methanol emission originates from hot (Tgas ≃ 700 K) material, ∼2″ (0.02 pc) across, centered on the dust-obscured binary, and is accompanied by prominent absorption of continuum radiation in a cooler (Tgas ≃ 110 K) layer of gas. We also report a first detection of water in Herschel observations at 557 and 988 GHz. The methanol abundance is several to 50 times higher than observed toward several lower-mass stars, while water abundances are similar to those observed in cool, dense molecular clouds. The very high methanol:water abundance ratio in the core of η Car may suggest methanol formation processes similar to Fischer-Tropsch-type catalytic reactions on dust grains. These observations prove that complex molecule formation can occur in a chemically evolved massive stellar environment, given sufficient gas densities and shielding conditions as may occur in material around massive interacting companions and merger remnants.

Keywords: Reaction catalysts, Massive stars, Luminous blue variable stars, Astrochemistry, Circumstellar matter
The Lowest of the Low: Discovery of SN 2019gsc and the Nature of Faint Iax Supernovae. We present the discovery and optical follow-up of the faintest supernova-like transient known. The event (SN 2019gsc) was discovered in a star-forming host at 53 Mpc by ATLAS. A detailed multicolor light curve was gathered with Pan-STARRS1 and follow-up spectroscopy was obtained with the Nordic Optical Telescope and Gemini-North. The spectra near maximum light show narrow features at low velocities of 3000-4000 km s-1, similar to the extremely low-luminosity SNe 2010ae and 2008ha, and the light curve displays a similar fast decline (∆m15(r) = 0.91 ± 0.10 mag). SNe 2010ae and 2008ha have been classified as SNe Iax, and together the three either make up a distinct physical class of their own or are at the extreme low-luminosity end of this diverse supernova population. The bolometric light curve is consistent with a low kinetic energy of explosion (Ek ∼ 1049 erg s-1), a modest ejected mass (Mej ∼ 0.2 M☉), and radioactive powering by 56Ni (MNi ∼ 2 × 10-3 M☉). The spectra are quite well reproduced with radiative transfer models (TARDIS) and a composition dominated by carbon, oxygen, magnesium, silicon, and sulfur. Remarkably, all three of these extreme Iax events are in similar low-metallicity star-forming environments. The combination of the observational constraints for all three may be best explained by deflagrations of near MCh hybrid carbon-oxygen-neon white dwarfs that have short evolutionary pathways to formation.

Keywords: Type Ia supernovae, Supernovae
Multiwavelength Follow-up of the Hyperluminous Intermediate-mass Black Hole Candidate 3XMM J215022.4-055108. We recently discovered the X-ray/optical outbursting source 3XMM J215022.4-055108. It was best explained as the tidal disruption of a star by an intermediate-mass black hole of mass of a few tens of thousand solar masses in a massive star cluster at the outskirts of a large barred lenticular galaxy at DL = 247 Mpc. However, we could not completely rule out a Galactic cooling neutron star as an alternative explanation for the source. In order to further pin down the nature of the source, we have obtained new multiwavelength observations by XMM-Newton and the Hubble Space Telescope (HST). The optical counterpart to the source in the new HST image is marginally resolved, which rules out the Galactic cooling neutron star explanation for the source and suggests a star cluster of half-light radius ∼27 pc. The new XMM-Newton observation indicates that the luminosity was decaying as expected for a tidal disruption event and that the disk was still in the thermal state with a supersoft X-ray spectrum. Therefore, the new observations confirm the source as one of the best intermediate-mass black hole candidates.

Keywords: Black hole physics, Intermediate-mass black holes, Tidal disruption, X-ray transient sources, Ultracompact dwarf galaxies, Stellar accretion disks
LAMOST J040643.69+542347.8: The Fastest Rotator in the Galaxy. Rotation and binary interaction play important roles in understanding the nature of massive stars (≳8M⊙). Some interesting transients, such as the long-duration gamma-ray bursts, are thought to be originated from fast-rotating massive stars. Because the strong stellar wind can effectively spin down a metal-rich massive star with fast rotation, it is very hard to find single massive stars rotating critically in the Galaxy. In the present work reported is the discovery of the fastest rotator in the Galaxy, LAMOST J040643.69+542347.8, with a projected rotational velocity Ve sin I ∼ 540 km s-1, which is ∼100 km s-1 faster than that of the previous record holder HD 191423. The star has a spectral type of O6.5 Vnnn(f)p. Its He I λ4471 absorption line is blueshifted and asymmetric, while its He II λ4686 and Hα have central absorption reversals in their emissions. It is also a runaway star, which implies an origin in a close binary interaction. Compared to VFTS 285 and VFTS 102 (their Ve sin I ∼ 610 km s-1) in the Large Magellanic Cloud, LAMOST J040643.69+542347.8 has its own peculiar spectral characteristics and earlier spectral type. Moreover, LAMOST J040643.69+542347.8 is bright (B ∼ 13.9 mag) enough to allow future high-resolution spectroscopic follow-up.

Keywords: Stellar rotation, Massive stars
Could Quasar Lensing Time Delays Hint to a Core Component in Halos, Instead of H<SUB>0</SUB> Tension?. The time delay measured between the images of gravitationally lensed quasars probes a combination of the angular diameter distance to the source-lens system and the mass density profile of the lens. Observational campaigns to measure such systems have reported a determination of the Hubble parameter H0 that shows significant tension with independent determination based on the cosmic microwave background (CMB) and large-scale structure (LSS). We show that lens mass models that exhibit a cored component, coexisting with a cusp, probe a degenerate direction in the lens model parameter space, being an approximate mass sheet transformation. This family of lens models has not been considered by the cosmographic analyses. Once added to the model, the cosmographic error budget should become dependent on stellar kinematics uncertainties. We propose that a core component coexisting with a cusp could bring the lensing measurements of H0 into accordance with the CMB/LSS value.

Keywords: Hubble constant, Strong gravitational lensing, Galaxy structure, Gravitational lensing
Supernova Magnitude Evolution and PAge Approximation. The evidence of environmental dependence of SN Ia luminosity has inspired recent discussion about whether the late-universe cosmic acceleration is still supported by supernova data. We adopt the ΔHR/Δage parameter, which describes the dependence of supernova absolute magnitude on the age of supernova progenitor, as an additional nuisance parameter. Using the Pantheon supernova data, a lower bound ≥12 Gyr on the cosmic age, and a Gaussian prior H0=70± 2 km s-1 Mpc-1 on the Hubble constant, we reconstruct the cosmic expansion history. Within the flat Λ cold dark matter framework, we still find a 5.6σ detection of cosmic acceleration. This is because a matter-dominated decelerating universe would be too young to accommodate observed old stars with age ≳12 Gyr. A decelerating but non-flat universe is marginally consistent with the data, however, only in the presence of a negative spatial curvature ∼2 orders of magnitude beyond the current constraint from cosmic microwave background data. Finally, we propose a more general parameterization based on the cosmic age (PAge), which is not directly tied to the dark energy concept and hence is ideal for a null test of the cosmic acceleration. We find that, for a magnitude evolution rate ΔHR/Δage ≲ 0.3 mag/5.3 Gyr, a spatially flat and decelerating PAge universe is fully consistent with the supernova data and the cosmic age bound, and has no tension with the geometric constraint from the observed cosmic microwave background acoustic angular scales.

Keywords: Cosmology, Cosmological constant experiments, Observational cosmology, Dark energy
Inner Boundary Condition in Quasi-Lagrangian Simulations of Accretion Disks. In simulations of viscously evolving accretion disks, the inner boundary condition is particularly important. If treated incorrectly, it induces incorrect behavior very quickly, because the viscous time is shortest near the inner boundary. Recent work has determined the correct inner boundary in Eulerian simulations. But in quasi-Lagrangian simulations (e.g., SPH, moving mesh, and meshless), where the inner boundary is modeled by removing mass within a finite zone, the inner density profile typically becomes anomalously depleted. Here we show how the boundary condition should be applied in such codes, via a simple modification of the usual approach: when one removes mass, one must speed up the remaining material so that the disk's angular momentum is unchanged. We show with both 1D and 2D moving-mesh (AREPO) simulations that this scheme works as desired in viscously evolving disks. It produces no spurious density depletions and is independent of the mass removal rate, provided that the disk is adequately resolved and that the mass removal rate is not so extreme as to trigger instabilities. This "torque-free" mass removal technique permits the use of quasi-Lagrangian codes to simulate viscously evolving disks, while including a variety of additional effects. As an example, we apply our scheme to a 2D simulation of an accretion disk perturbed by a very massive planet, in which the disk is evolved to viscous steady state.

Keywords: Planetary system formation, Computational methods, Protoplanetary disks, Circumstellar disks, Stellar accretion disks, Planet formation
Time Variations in the Flux Density of Sgr A* at 230 GHz Detected with ALMA. A radio source at the Galactic center Sgr A* is a prime supermassive black hole candidate and therefore key to developing our understanding of them. Time variations in the 230 GHz band flux of Sgr A* have been found with the Atacama Large Millimeter/submillimeter Array Cycle 5 observations. Measuring the flux density of Sgr A* in 1 minute snapshots at 217.5, 219.5, and 234.0 GHz, we obtained light curves for ten 70 minute periods. The light curves show variations at a few tens of minutes and hourly scales. The shorter timescale is similar to the orbital period of the innermost stable circular orbit around a 4 × 106 M⊙ black hole, suggesting that the variation originates from the immediate vicinity of Sgr A*. We also detected no time lag between 217.5 and 234.0 GHz and a dependence of the spectral index on the flux density.

Keywords: Black hole physics, Supermassive black holes, Galactic center, Low-luminosity active galactic nuclei, Radio astronomy
Source Depth of Three-minute Umbral Oscillations. We infer the depth of the internal sources giving rise to three-minute umbral oscillations. Recent observations of ripple-like velocity patterns of umbral oscillations supported the notion that there exist internal sources exciting the umbral oscillations. We adopt the hypothesis that the fast magnetohydrodynamic (MHD) waves generated at a source below the photospheric layer propagate along different paths, reach the surface at different times, and excited slow MHD waves by mode conversion. These slow MHD waves are observed as the ripples that apparently propagate horizontally. The propagation distance of the ripple given as a function of time is strongly related to the depth of the source. Using the spectral data of the Fe I 5435 Å line taken by the Fast Imaging Solar Spectrograph of the Goode Solar Telescope at Big Bear Solar Observatory, we identified five ripples and determined the propagation distance as a function of time in each ripple. From the model fitting to these data, we obtained the depth between 1000 and 2000 km. Our result will serve as an observational constraint to understanding the detailed processes of magnetoconvection and wave generation in sunspots.

Keywords: Helioseismology, Sunspots
Probabilistic Detection of Spectral Line Components. Resolved kinematical information, such as from molecular gas in star-forming regions, is obtained from spectral line observations. However, these observations often contain multiple line-of-sight components, making estimates harder to obtain and interpret. We present a fully automatic method that determines the number of components along the line of sight, or the spectral multiplicity, through Bayesian model selection. The underlying open-source framework, based on nested sampling and conventional spectral line modeling, is tested using the large area ammonia maps of NGC 1333 in the Perseus molecular cloud obtained by the Green Bank Ammonia Survey (GAS). Compared to classic approaches, the presented method constrains velocities and velocity dispersions in a larger area. In addition, we find that the velocity dispersion distribution among multiple components did not change substantially from that of a single-fit component analysis of the GAS data. These results showcase the power and relative ease of the fitting and model selection method, which makes it a unique tool to extract maximum information from complex spectral data.

Keywords: Computational methods, Star forming regions