adsabs/SciX_UAT_keywords huggingface dataset:
High-frequency Wave Power Observed in the Solar Chromosphere with IBIS and ALMA

We present observational constraints on the chromospheric heating contribution from acoustic waves with frequencies between 5 and 50 mHz. We use observations from the Dunn Solar Telescope in New Mexico, complemented with observations from the Atacama Large Millimeter Array collected on 2017 April 23. The properties of the power spectra of the various quantities are derived from the spectral lines of Ca II 854.2 nm, H I 656.3 nm, and the millimeter continuum at 1.25 and 3 mm. At the observed frequencies, the diagnostics almost all show a power-law behavior, whose particulars (slope, peak, and white-noise floors) are correlated with the type of solar feature (internetwork, network, and plage). In order to disentangle the vertical versus transverse Alfvénic plasma motions, we examine two different fields of view: one near disk center, and the other close to the limb. To infer the acoustic flux in the middle chromosphere, we compare our observations with synthetic observables from the time-dependent radiative hydrodynamic RADYN code. Our findings show that acoustic waves carry up to about 1 kW m-2 of energy flux in the middle chromosphere, which is not enough to maintain the quiet chromosphere. This is in contrast to previous publications.

Keywords: solar atmosphere; spectroscopy; radiative transfer
Automatic Satellite Identification in Digital Images

Using a digital camera on the roof of the Royal Observatory, Edinburgh, images are continuously captured of the sky on a nightly basis to image satellites which pass overhead. Such satellites are seen in images as short lines since satellites move much quicker in the sky than stars, and up to 100 satellites can be imaged in one night. Using these images, software was developed (GitHub repository for code & documentation: https://github.com/Jack6228/STM_Final, or DOI: https://doi.org/10.5281/zenodo.7304283.) to use known catalogs of artificial objects which orbit the Earth to determine which satellites can be seen in each image. This was achieved by comparing the expected positions of satellites in the catalog to those observed by the camera to identify matches. Overall, the project was a success and satellites are able to be identified approximately 85% of the time, which could help track space debris in a cheaper manner in a world where space is becoming increasingly more polluted.

Keywords: artificial satellites; astronomy image processing; observational astronomy; astronomical instrumentation; astronomy software; geostationary satellites; astronomy data analysis; astronomy data acquisition
How Does Environment Affect the Morphology of Radio AGN?

Galaxies hosting Active Galactic Nuclei (AGN) with bent radio jets are used as tracers of dense environments, such as galaxy groups and clusters. The assumption behind using these jets is that they are bent under ram pressure from a dense, gaseous medium through which the host galaxy moves. However, there are many AGN in groups and clusters with jets that are not bent, which leads us to ask: why are some AGN jets affected so much by their environment while others are seemingly not? We present the results of an environmental study on a sample of 185 AGN with bent jets and 191 AGN with unbent jets in which we characterize their environments by searching for neighboring galaxies using a Friends-of-Friends algorithm. We find that AGN with bent jets are indeed more likely to reside in groups and clusters, while unbent AGN are more likely to exist in singles or pairs. When considering only AGN in groups of three or more galaxies, we find that bent AGN are more likely to exist in halos with more galaxies than unbent AGN. We also find that unbent AGN are more likely than bent AGN to be the brightest group galaxy. Additionally, groups hosting AGN with bent jets have a higher density of galaxies than groups hosting unbent AGN. Curiously, there is a population of AGN with bent jets that are in seemingly less dense regions of space, indicating they may be embedded in a cosmic web filament. Overall, our results indicate that bent doubles are more likely to exist in in larger, denser, and less relaxed environments than unbent doubles, potentially linking a galaxy's radio morphology to its environment.

Keywords: agn host galaxies; radio active galactic nuclei; radio continuum emission; galaxy groups; galaxy clusters; intracluster medium; intergalactic medium; galaxy environments
Locating Red Supergiants in the Galaxy IC10

We use archival near-IR photometry to identify red supergiants (RSGs) in the starburst galaxy IC10. RSGs are the coolest of the evolved massive stars and have K and M spectral types and temperatures below 4100 K. Typically, they can be up to a thousand times the radius of the Sun, and are therefore highly luminous. Using archival 2MASS and UKIRT photometry we transformed J and K colors to effective temperatures and luminosities, which allowed us to identify the RSGs. After applying temperature and luminosity constraints and eliminating foreground stars using Gaia, we arrived at our finalized list of 138 RSGs. Of this list, 26 were confirmed RSGs based on Gaia parallaxes, with the remaining 112 being unconfirmed proposed IC10 RSGs.

Keywords: red supergiant stars; late-type supergiant stars; supergiant stars; starburst galaxies; active galaxies
Global Stellar Budget for LIGO Black Holes

The binary black hole mergers observed by Laser Interferometer Gravitational-Wave Observatory (LIGO)-Virgo gravitational-wave detectors pose two major challenges: (I) how to produce these massive black holes from stellar processes; and (II) how to bring them close enough to merge within the age of the universe? We derive a fundamental constraint relating the binary separation and the available stellar budget in the universe to produce the observed black hole mergers. We find that ≲14% of the entire budget contributes to the observed merger rate of (30+30) M⊙ black holes, if the separation is around the diameter of their progenitor stars. Furthermore, the upgraded LIGO detector and third-generation gravitational-wave detectors are not expected to find stellar-mass black hole mergers at high redshifts. From LIGO's strong constraints on the mergers of black holes in the pair-instability mass gap (60-120 M⊙), we find that ≲0.8% of all massive stars contribute to a remnant black hole population in this gap. Our derived separation-budget constraint provides a robust framework for testing the formation scenarios of stellar binary black holes.

Keywords: astrophysical black holes; gravitational wave astronomy
Exploring the Structures and Substructures of the Andromeda Satellite Dwarf Galaxies Cassiopeia III, Perseus I, and Lacerta I

We present results from wide-field imaging of the resolved stellar populations of the dwarf spheroidal galaxies Cassiopeia III (And XXXII) and Perseus I (And XXXIII), two satellites in the outer stellar halo of the Andromeda galaxy (M31). Our WIYN pODI photometry traces the red giant star population in each galaxy to ~2.5-3 half-light radii from the galaxy center. We use the tip of the red giant branch (TRGB) method to derive distances of (m - M)0 = 24.62 ± 0.12 mag (839 ${}_{-45}^{+48}$ kpc, or ${156}_{-13}^{+16}$ kpc from M31) for Cas III and 24.47 ± 0.13 mag (738 ${}_{-45}^{+48}$ kpc, or 351 ${}_{-16}^{+17}$ kpc from M31) for Per I. These values are consistent within the errors with TRGB distances derived from a deeper Hubble Space Telescope study of the galaxies' inner regions. For each galaxy, we derive structural parameters, total magnitude, and central surface brightness. We also place upper limits on the ratio of neutral hydrogen gas mass to optical luminosity, confirming the gas-poor nature of both galaxies. We combine our data set with corresponding data for the M31 satellite galaxy Lacerta I (And XXXI) from earlier work and search for substructure within the RGB star populations of Cas III, Per I, and Lac I. We find an overdense region on the west side of Lac I at a significance level of 2.5σ-3σ and a low-significance filament extending in the direction of M31. In Cas III, we identify two modestly significant overdensities near the center of the galaxy and another at two half-light radii. Per I shows no evidence for substructure in its RGB star population, which may reflect this galaxy's isolated nature.

Keywords: dwarf galaxies; local group; andromeda galaxy; dwarf spheroidal galaxies; sloan photometry; broad band photometry; galaxy stellar content; stellar populations
Wave Conversion, Decay, and Heating in a Partially Ionized Two-fluid Magneto-atmosphere

A ray-theoretic phase-space description of linear waves in a two-fluid (charges and neutrals) magnetized plasma is used to calculate analytic decay rates and mode transmission and conversion coefficients between fast and slow waves in two dimensions due to finite ion-neutral collision frequencies at an arbitrary ionization fraction. This is relevant to partially ionized astrophysical plasmas, in particular solar and stellar atmospheres. The most important parameter governing collisional effects is the ratio of the wave frequency to the neutral-charges collision frequency, ϵ = ω/ν nc, with secondary dependence on ionization fraction and wave attack angle. Comparison is made to the one-fluid magnetohydrodynamic case, and it is found that acoustic-to-acoustic and magnetic-to-magnetic transmission through the Alfvén-acoustic equipartition layer is decreased by a term of ${ \mathcal O }({\epsilon }^{2})$ relative to one-fluid (infinite collision frequency), and correspondingly acoustic-to-magnetic and magnetic-to-acoustic conversion is increased. The neutral-acoustic mode is shown to dissipate rapidly as ν nc → ∞. Away from the mode conversion region, dissipative decay along the remaining magneto-acoustic rays scales as ${ \mathcal O }(\epsilon )$ and is found to be much more effective on magnetically dominated rays compared to acoustically dominated rays. This produces a steep jump in dissipation in mode conversion regions, where the rays change character, and can produce localized heating there and beyond. Applications to the solar chromosphere are discussed.

Keywords: solar atmosphere; plasma astrophysics; magnetohydrodynamics
Planets Across Space and Time (PAST). II. Catalog and Analyses of the LAMOST-Gaia-Kepler Stellar Kinematic Properties

The Kepler telescope has discovered over 4000 planets (candidates) by searching ~200,000 stars over a wide range of distance (order of kpc) in our Galaxy. Characterizing the kinematic properties (e.g., Galactic component membership and kinematic age) of these Kepler targets (including the planet candidate hosts) is the first step toward studying Kepler planets in the Galactic context, which will reveal fresh insights into planet formation and evolution. In this paper, the second part of the Planets Across the Space and Time (PAST) series, by combining the data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and Gaia and then applying the revised kinematic methods from PAST I, we present a catalog of kinematic properties (i.e., Galactic positions, velocities, and the relative membership probabilities among the thin disk, thick disk, Hercules stream, and the halo) as well as other basic stellar parameters for 35,835 Kepler stars. Further analyses of the LAMOST-Gaia-Kepler catalog demonstrate that our derived kinematic age reveals the expected stellar activity-age trend. Furthermore, we find that the fraction of thin (thick) disk stars increases (decreases) with the transiting planet multiplicity (Np = 0, 1, 2 and 3+) and the kinematic age decreases with Np, which could be a consequence of the dynamical evolution of planetary architecture with age. The LAMOST-Gaia-Kepler catalog will be useful for future studies on the correlations between the exoplanet distributions and the stellar Galactic environments as well as ages.

Keywords: exoplanet catalogs; stellar kinematics; exoplanets
Analysis of Four-band WISE Observations of Asteroids

We analyzed 82,548 carefully curated observations of 4420 asteroids with Wide-field Infrared Survey Explorer (WISE) four-band data to produce estimates of diameters and infrared emissivities. We also used these diameter values in conjunction with absolute visual magnitudes to infer estimates of visible-band geometric albedos. We provide solutions to 131 asteroids not analyzed by the NEOWISE team and to 1778 asteroids not analyzed with four-band data by the NEOWISE team. Our process differs from the NEOWISE analysis in that it uses an accurate solar flux, integrates the flux with actual bandpass responses, obeys Kirchhoff's law, and does not force emissivity values in all four bands to an arbitrary value of 0.9. We used a regularized model-fitting algorithm that yields improved fits to the data. Our results more closely match stellar-occultation diameter estimates than the NEOWISE results by a factor of ~2. Using 24 high-quality stellar-occultation results as a benchmark, we found that the median error of four-infrared-band diameter estimates in a carefully curated data set is 9.3%. Our results also suggest the presence of a size-dependent bias in the NEOWISE diameter estimates, which may pollute estimates of asteroid size distributions and slightly inflate impact-hazard risk calculations. For more than 90% of asteroids in this sample, the primary source of error on the albedo estimate is the error on absolute visual magnitude.

Keywords: asteroids; asteroid surfaces; main belt asteroids; near-earth objects
Efficient Mass Estimate at the Core of Strong Lensing Galaxy Clusters Using the Einstein Radius

In the era of large surveys, yielding thousands of galaxy clusters, efficient mass proxies at all scales are necessary in order to fully utilize clusters as cosmological probes. At the cores of strong lensing clusters, the Einstein radius can be turned into a mass estimate. This efficient method has been routinely used in literature, in lieu of detailed mass models; however, its scatter, assumed to be $\sim 30 \% $ , has not yet been quantified. Here, we assess this method by testing it against ray-traced images of cluster-scale halos from the Outer Rim N-body cosmological simulation. We measure a scatter of 13.9% and a positive bias of 8.8% in $M(\lt {\theta }_{{\rm{E}}})$ , with no systematic correlation with total cluster mass, concentration, or lens or source redshifts. We find that increased deviation from spherical symmetry increases the scatter; conversely, where the lens produces arcs that cover a large fraction of its Einstein circle, both the scatter and the bias decrease. While spectroscopic redshifts of the lensed sources are critical for accurate magnifications and time delays, we show that for the purpose of estimating the total enclosed mass, the scatter introduced by source redshift uncertainty is negligible compared to other sources of error. Finally, we derive and apply an empirical correction that eliminates the bias, and reduces the scatter to 10.1% without introducing new correlations with mass, redshifts, or concentration. Our analysis provides the first quantitative assessment of the uncertainties in $M(\lt {\theta }_{{\rm{E}}})$ , and enables its effective use as a core mass estimator of strong lensing galaxy clusters.

Keywords: galaxy clusters; strong gravitational lensing; dark matter
A Detailed Temperature Map of the Archetypal Protostellar Shocks in L1157

We present sensitive NH3 (1,1)-(7,7) line images from the Karl G. Jansky Very Large Array toward successive shocks, which are associated with the blueshifted outflow lobe driven by the compact protobinary system L1157. Within a projection distance of 0.1 pc, our observations not only trace the quiescent and cold gas in the flattened envelope, but also illustrate the complex physical and chemical processes that take place where the high-velocity jet impinges on its surrounding medium. Specifically, the NH3 ortho-to-para ratio is enhanced by a factor of 2-2.5 along the jet path, where the velocity offset between the line peak and the blueshifted wing reaches values as high as 10 km s-1; it also shows a strong spatial correlation with the NH3 column density, which is enhanced to >1016 cm-2 toward the shock cavities. At a linear resolution of 1500 au, our refined temperature map from the seven NH3 lines shows a gradient from the warm B0 eastern cavity wall (>120 K) to the cool cavity B1 and the earlier shock B2 (<80 K), indicating shock heating.

Keywords: low mass stars; stellar bow shocks; astrochemistry
Mechanisms for Limiting the Depth of Zonal Winds in the Gas Giant Planets

Gravity signatures observed by the Juno and Cassini missions that are associated with the strong zonal winds in Jupiter's and Saturn's outer envelopes suggest that these flows extend for several thousand kilometers into the interior. It has been noted that the winds seem to abate at a depth where electrical conductivity becomes significant, suggesting that electromagnetic effects play a key role for confining the winds to the outer weakly conducting region. Here, we explore the possible mechanisms for braking the zonal flow at depth in two model setups with depth-dependent conductivity and forced jet flow, I.e., in axisymmetric shell models and in more simple linearized box models that allow the exploration of a wide parameter range. Braking of the winds directly by Lorentz forces does not reduce their speed in the conducting region enough to be compatible with the inferred secular variation of Jupiter's field. Stable stratification above the depth where conductivity becomes significant can solve the problem. Electromagnetic forces drive a weak meridional circulation that perturbs the density distribution in the stable region such that the wind speed decreases strongly with depth, due to a thermal wind balance. For this mechanism to be effective, the stable layer must extend upward into a region of low conductivity. Applying the results of the linearized calculations to Jupiter suggests that the dissipation associated with the zonal winds can be limited to a fraction of the internal heat flow and that the jets may drop off over a depth range of 150-300 km.

Keywords: planetary structure
Was Venus Ever Habitable? Constraints from a Coupled Interior-Atmosphere-Redox Evolution Model

Venus's past climate evolution is uncertain. General circulation model simulations permit a habitable climate as late as ~0.7 Ga, and there is suggestive-albeit inconclusive-evidence for previous liquid water from surface geomorphology and mineralogy. However, it is unclear whether a habitable past can be reconciled with Venus's inferred atmospheric evolution. In particular, the lack of leftover atmospheric oxygen argues against recent water loss. Here, we apply a fully coupled model of Venus's atmospheric-interior-climate evolution from post-accretion magma ocean to present. The model self-consistently tracks C-, H-, and O-bearing volatiles and surface climate through the entirety of Venus's history. Atmospheric escape, mantle convection, melt production, outgassing, deep water cycling, and carbon cycling are explicitly coupled to climate and redox evolution. Plate tectonic and stagnant lid histories are considered. Using this coupled model, we conclude that both a habitable Venusian past and one where Venus never possessed liquid surface water can be reconciled with known constraints. Specifically, either scenario can reproduce bulk atmospheric composition, inferred surface heat flow, and observed 40Ar and 4He. Moreover, the model suggests that Venus could have been habitable with a ~100 m global ocean as late as 1 Ga, without violating any known constraints. In fact, if diffusion-limited water loss is throttled by a cool, CO2-dominated upper atmosphere, then a habitable past is tentatively favored by our model. This escape throttling makes it difficult to simultaneously recover negligible water vapor and ~90 bar CO2 in the modern atmosphere without temporarily sequestering carbon in the interior via silicate weathering to enhance H escape.

Keywords: venus; solar system terrestrial planets; planetary atmospheres; planetary climates; atmospheric composition; planetary interior; tectonics; volcanoes; habitable planets
BASS. XXV. DR2 Broad-line-based Black Hole Mass Estimates and Biases from Obscuration

We present measurements of broad emission lines and virial estimates of supermassive black hole masses (M BH) for a large sample of ultrahard X-ray-selected active galactic nuclei (AGNs) as part of the second data release of the BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes M BH estimates for a total of 689 AGNs, determined from the Hα, Hβ, Mg II λ2798, and/or C IV λ1549 broad emission lines. The core sample includes a total of 512 AGNs drawn from the 70 month Swift/BAT all-sky catalog. We also provide measurements for 177 additional AGNs that are drawn from deeper Swift/BAT survey data. We study the links between M BH estimates and line-of-sight obscuration measured from X-ray spectral analysis. We find that broad Hα emission lines in obscured AGNs ( ) are on average a factor of weaker relative to ultrahard X-ray emission and about % narrower than those in unobscured sources (i.e., ). This indicates that the innermost part of the broad-line region is preferentially absorbed. Consequently, current single-epoch M BH prescriptions result in severely underestimated (>1 dex) masses for Type 1.9 sources (AGNs with broad Hα but no broad Hβ) and/or sources with . We provide simple multiplicative corrections for the observed luminosity and width of the broad Hα component (L[bHα] and FWHM[bHα]) in such sources to account for this effect and to (partially) remedy M BH estimates for Type 1.9 objects. As a key ingredient of BASS/DR2, our work provides the community with the data needed to further study powerful AGNs in the low-redshift universe.

Keywords: active galactic nuclei; surveys; catalogs; supermassive black holes; x-ray surveys; m-sigma relation; seyfert galaxies
Discovery of a Large and Faint Nebula at the Triangulum Galaxy

We report the discovery of a previously uncatalogued arch-shaped filamentary nebula at the outer part of the Triangulum galaxy (M33) centered at α = 1h34m25s, $\delta =+30^\circ 20^{\prime} 17^{\prime\prime} $ (ICRS). This discovery stems from meticulous observations employing deep exposures of M33, using both Hα and [O III] narrow-band filters. The nebula, designated as Roig1 Prades Sky, exhibits an Hα surface brightness of $23.9\,\mathrm{mag}\,{\mathrm{arcsec}}^{-2}$ . Its sky projected location is 21' away from the M33 galactic center toward the southeast direction with an extent of (120 × 440) ± 30 pc. Deep spectroscopic observations are required to unveil its real nature.

Keywords: astrophotography; optical astronomy; nebulae; h alpha photometry