adsabs/SciX_UAT_keywords huggingface dataset:
SMC-Last Extracted Photometry

We present point-source photometry from the Spitzer Space Telescope's final survey of the Small Magellanic Cloud (SMC). We mapped nearly 30 deg2 in two epochs in 2017, with the second extending to early 2018 at 3.6 and 4.5 μm using the Infrared Array Camera. This survey duplicates the footprint from the SAGE-SMC program in 2008. Together, these surveys cover a nearly 10 yr temporal baseline in the SMC. We performed aperture photometry on the mosaicked maps produced from the new data. We did not use any prior catalogs as inputs for the extractor in order to be sensitive to any moving objects (e.g., foreground brown dwarfs) and other transient phenomena (e.g., cataclysmic variables or FU Ori–type eruptions). We produced a point-source catalog with high-confidence sources for each epoch as well as a combined-epoch catalog. For each epoch and the combined-epoch data, we also produced a more complete archive with lower-confidence sources. All of these data products will be made available to the community at the Infrared Science Archive.

Keywords: small magellanic cloud; infrared photometry; celestial objects catalogs
Debris Disk Results from the Gemini Planet Imager Exoplanet Survey's Polarimetric Imaging Campaign

We report the results of a ∼4 yr direct imaging survey of 104 stars to resolve and characterize circumstellar debris disks in scattered light as part of the Gemini Planet Imager (GPI) Exoplanet Survey. We targeted nearby (≲150 pc), young (≲500 Myr) stars with high infrared (IR) excesses (LIR/L⋆ > 10-5), including 38 with previously resolved disks. Observations were made using the GPI high-contrast integral field spectrograph in H-band (1.6 μm) coronagraphic polarimetry mode to measure both polarized and total intensities. We resolved 26 debris disks and 3 protoplanetary/transitional disks. Seven debris disks were resolved in scattered light for the first time, including newly presented HD 117214 and HD 156623, and we quantified basic morphologies of five of them using radiative transfer models. All of our detected debris disks except HD 156623 have dust-poor inner holes, and their scattered-light radii are generally larger than corresponding radii measured from resolved thermal emission and those inferred from spectral energy distributions. To assess sensitivity, we report contrasts and consider causes of nondetections. Detections were strongly correlated with high IR excess and high inclination, although polarimetry outperformed total intensity angular differential imaging for detecting low-inclination disks (≲70°). Based on postsurvey statistics, we improved upon our presurvey target prioritization metric predicting polarimetric disk detectability. We also examined scattered-light disks in the contexts of gas, far-IR, and millimeter detections. Comparing H-band and ALMA fluxes for two disks revealed tentative evidence for differing grain properties. Finally, we found no preference for debris disks to be detected in scattered light if wide-separation substellar companions were present.

Keywords: astronomy data modeling; surveys; debris disks; circumstellar dust; exoplanet systems; protoplanetary disks; direct imaging; near infrared astronomy; circumstellar disks; coronagraphic imaging; polarimetry
Detection of Polarization due to Cloud Bands in the Nearby Luhman 16 Brown Dwarf Binary

Brown dwarfs exhibit patchy or spatially varying banded cloud structures that are inferred through photometric and spectroscopic variability modeling techniques. However, these methods are insensitive to rotationally invariant structures, such as the bands seen in Jupiter. Here, we present H-band Very Large Telescope/NaCo linear polarization measurements of the nearby Luhman 16 L/T transition binary, which suggest that Luhman 16A exhibits constant longitudinal cloud bands. The instrument was operated in pupil tracking mode, allowing us to unambiguously distinguish between a small astrophysical polarization and the ∼2% instrumental linear polarization. We measure the degree and angle of linear polarization of Luhman 16A and B to be pA = 0.031% ± 0.004% and ψA = -32° ± 4°, and pB = 0.010% ± 0.004% and ${\psi }_{B}={73}_{-11}^{+13\circ} $ , respectively. Using known physical parameters of the system, we demonstrate that an oblate homogeneous atmosphere cannot account for the polarization measured in Luhman 16A, but could be responsible for that of the B component. Through a nonexhaustive search of banded cloud morphologies, we demonstrate a two-banded scenario that can achieve a degree of linear polarization of p = 0.03% and conclude that the measured polarization of the A component must be predominantly due to cloud banding. For Luhman 16B, either oblateness or cloud banding could be the dominant source of the measured polarization. The misaligned polarization angles of the two binary components tentatively suggest spin-orbit misalignment. These measurements provide new evidence for the prevalence of cloud banding in brown dwarfs while at the same time demonstrating a new method—complementary to photometric and spectroscopic variability methods—for characterizing the cloud morphologies of substellar objects without signs of variability.

Keywords: near infrared astronomy; very large telescope; polarimetry
Sensitivity Testing of Stereophotoclinometry for the OSIRIS-REx Mission. I. The Accuracy and Errors of Digital Terrain Modeling

Stereophotoclinometry (SPC) was the prime method of shape modeling for NASA's OSIRIS-REx mission to asteroid Bennu. Here we describe the extensive testing conducted before launch to certify SPC as NASA Class B flight software, which not only validated SPC for operational use but also quantified the accuracy of this technique. We used a computer-generated digital terrain model (DTM) of a synthetic asteroid as the truth input to render simulated truth images per the planned OSIRIS-REx observing campaign. The truth images were then used as input to SPC to create testing DTMs. Imaging sets, observational parameters, and processing techniques were varied to evaluate their effects on SPC's performance and their relative importance for the quality of the resulting DTMs. We show that the errors in accuracy for SPC models are of the order of the source images' smallest pixel sizes and that a DTM can be created at any scale, provided there is sufficient imagery at that scale. Uncertainty in the spacecraft's flight path has minimal impact on the accuracy of SPC models. Subtraction between two DTMs (truth and simulated) is an effective approach for measuring error but has limitations. Comparing the simulated truth images with images rendered from the SPC-derived DTMs provides an excellent metric for DTM quality at smaller scales and can also be applied in flight by using real images of the target. SPC has limitations near steep slopes (e.g., the sides of boulders), leading to height errors of more than 30%. This assessment of the accuracy and sensitivity of SPC provides confidence in this technique and lessons that can be applied to future missions.

Keywords: asteroids; small solar system bodies; near-earth objects
A Flexible Gaussian Process Reconstruction Method and the Mass Function of the Coalescing Binary Black Hole Systems

We develop a new method based on Gaussian processes to reconstruct the mass distribution of binary black holes (BBHs). Instead of prespecifying the formalisms of mass distribution, we introduce a more flexible and nonparametric model with which the distribution can be mainly determined by the observed data. We first test our method with simulated data and find that it can well recover the injected distribution. Then, we apply this method to analyze the data of BBHs' observations from LIGO-Virgo Gravitational-Wave Transient Catalog 2. By reconstructing the chirp mass distribution, we find that there is a peak or a platform located at 20-30 M⊙ rather than a single-power-law-like decrease from low mass to high mass. Moreover, one or two peaks in the chirp mass range of ${ \mathcal M }\lt 20\,{M}_{\odot }$ may be favored by the data. Assuming a mass-independent mass ratio distribution of p(q) ∝ q1.4, we further obtain a distribution of primary mass and find that there is a feature located in the range of (30, 40) M⊙, which can be related to BROKEN POWER LAW and POWER LAW & PLUS PEAK distributions described in Collaboration et al. Besides, the merger rate of BBHs is estimated to be ${ \mathcal R }={26.29}_{-8.96}^{+14.21}\,{\mathrm{Gpc}}^{-3}\,{\mathrm{yr}}^{-1}$ , supposing that there is no redshift evolution.

Keywords: astrophysical black holes; gravitational wave astronomy; gaussian processes regression
ALMA Observations and Modeling of the Rotating Outflow in Orion Source I

We present 29SiO(J = 8-7) ν = 0, SiS (J = 19-18) ν = 0, and 28SiO (J = 8-7) ν = 1 molecular line archive observations made with the Atacama Large Millimeter/Submillimeter Array (ALMA) of the molecular outflow associated with Orion Source I. The observations show velocity asymmetries about the flow axis that are interpreted as outflow rotation. We find that the rotation velocity (∼4-8 km s-1) decreases with the vertical distance to the disk. In contrast, the cylindrical radius (∼100-300 au), the expansion velocity (∼2-15 km s-1), and the axial velocity vz (∼-1-10 km s-1) increase with the vertical distance. The mass estimated of the molecular outflow Moutflow ∼ 0.66-1.3 M⊙. Given a kinematic time ∼130 yr, this implies a mass-loss rate ${\dot{M}}_{\mathrm{outflow}}\sim 5.1-10\times {10}^{-3}$ M⊙ yr-1. This massive outflow sets important constraints on disk wind models. We compare the observations with a model of a shell produced by the interaction between an anisotropic stellar wind and an Ulrich accretion flow that corresponds to a rotating molecular envelope in collapse. We find that the model cylindrical radii are consistent with the 29SiO(J = 8-7) ν = 0 data. The expansion velocities and the axial velocities of the model are similar to the observed values, except for the expansion velocity close to the disk (z ∼ ±150 au). Nevertheless, the rotation velocities of the model are a factor ∼3-10 lower than the observed values. We conclude that the Ulrich flow alone cannot explain the rotation observed and other possibilities should be explored, like the inclusion of the angular momentum of a disk wind.

Keywords: stellar winds; protostars; stellar accretion
Data-constrained Solar Modeling with GX Simulator

To facilitate the study of solar flares and active regions, we have created a modeling framework, the freely distributed GX Simulator IDL package, that combines 3D magnetic and plasma structures with thermal and nonthermal models of the chromosphere, transition region, and corona. Its object-based modular architecture, which runs on Windows, Mac, and Unix/Linux platforms, offers the ability to either import 3D density and temperature distribution models, or to assign numerically defined coronal or chromospheric temperatures and densities, or their distributions, to each individual voxel. GX Simulator can apply parametric heating models involving average properties of the magnetic field lines crossing a given voxel, as well as compute and investigate the spatial and spectral properties of radio, (sub)millimeter, EUV, and X-ray emissions calculated from the model, and quantitatively compare them with observations. The package includes a fully automatic model production pipeline that, based on minimal users input, downloads the required SDO/HMI vector magnetic field data, performs potential or nonlinear force-free field extrapolations, populates the magnetic field skeleton with parameterized heated plasma coronal models that assume either steady-state or impulsive plasma heating, and generates non-LTE density and temperature distribution models of the chromosphere that are constrained by photospheric measurements. The standardized models produced by this pipeline may be further customized through specialized IDL scripts, or a set of interactive tools provided by the graphical user interface. Here, we describe the GX Simulator framework and its applications.

Keywords: solar active regions; solar flares; microwave spectroscopy; solar electromagnetic emission; astronomy data modeling; non-thermal radiation sources
The Infrared Emission and Vigorous Star Formation of Low-redshift Quasars

The star formation activity of the host galaxies of active galactic nuclei provides valuable insights into the complex interconnections between black hole growth and galaxy evolution. A major obstacle arises from the difficulty of estimating accurate star formation rates (SFRs) in the presence of a strong active galactic nucleus. Analyzing the 1-500 μm spectral energy distributions and high-resolution mid-infrared spectra of low-redshift (z < 0.5) Palomar-Green quasars with bolometric luminosity of ∼1044.5-1047.5 erg s-1, we find, from comparison with an independent SFR indicator based on [Ne II] 12.81 μm and [Ne III] 15.56 μm, that the torus-subtracted, total infrared (8-1000 μm) emission yields robust SFRs in the range of ∼1-250 M⊙ yr-1. Combined with available stellar mass estimates, the vast majority (∼75%-90%) of the quasars lie on or above the main sequence of local star-forming galaxies, including a significant fraction (∼50%-70%) that would qualify as starburst systems. This is further supported by the high star formation efficiencies derived from the gas content inferred from the dust masses. Inspection of high-resolution Hubble Space Telescope images reveals a wide diversity of morphological types, including a number of starbursting hosts that have not experienced significant recent dynamical perturbations. The origin of the high star formation efficiency is unknown.

Keywords: interstellar medium; quasars; agn host galaxies
Eccentric Black Hole Mergers in Active Galactic Nuclei

The astrophysical origin of gravitational wave transients is a timely open question in the wake of discoveries by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo. In active galactic nuclei (AGNs), binaries form and evolve efficiently by interaction with a dense population of stars and the gaseous AGN disk. Previous studies have shown that stellar-mass black hole (BH) mergers in such environments can explain the merger rate and the number of suspected hierarchical mergers observed by LIGO/Virgo. The binary eccentricity distribution can provide further information to distinguish between astrophysical models. Here we derive the eccentricity distribution of BH mergers in AGN disks. We find that eccentricity is mainly due to binary-single (BS) interactions, which lead to most BH mergers in AGN disks having a significant eccentricity at 0.01 Hz, detectable by the Laser Interferometer Space Antenna. If BS interactions occur in isotropic-3D directions, then 8%-30% of the mergers in AGN disks will have eccentricities at 10 Hz above e10 Hz ≳ 0.03, detectable by LIGO/Virgo/Kamioka Gravitational Wave Detector, while 5%-17% of mergers have e10 Hz ≥ 0.3. On the other hand, if BS interactions are confined to the AGN-disk plane due to torques from the disk, with 1-20 intermediate binary states during each interaction, or if BHs can migrate to ≲ 10-3 pc from the central supermassive BH, then 10%-70% of the mergers will be highly eccentric (e10 Hz ≥ 0.3), consistent with the possible high eccentricity in GW190521.

Keywords: active galactic nuclei; gravitational wave sources; close binary stars; n-body simulations; stellar mass black holes
Evolution of Galaxy Size in the FOGGIE Simulations

Cosmological simulations are a powerful tool to study galaxy evolution as they can span a substantial fraction of the cosmic time. In this research note, we use the Figuring Out Gas and Galaxies In Enzo simulations-cosmological hydrodynamic simulation of Milky Way-like galaxies-to measure the evolution of the radius of the galaxy disk. Additionally, we analyze the simulations along three different lines of sight. Lastly, we show that the disk size increases over time regardless of angle of projection.

Keywords: hydrodynamical simulations; galaxy evolution; milky way galaxy; milky way evolution; circumgalactic medium; galaxy disks
Spitzer Dayside Emission of WASP-34b

We analyzed two eclipse observations of the low-density transiting, likely grazing, exoplanet WASP-34b with the Spitzer Space Telescope's InfraRed Array Camera using two techniques to correct for intrapixel sensitivity variation: Pixel-Level Decorrelation and BiLinearly Interpolated Subpixel Sensitivity. When jointly fitting both light curves, timing results are consistent within 0.7σ between the two models and eclipse depths are consistent within 1.1σ, where the difference is due to photometry methods, not the models themselves. By combining published radial velocity data, amateur and professional transit observations, and our eclipse timings, we improved on measurements of orbital parameters and found an eccentricity consistent with zero (0.0). Atmospheric retrieval, using our Bayesian Atmospheric Radiative Transfer code, shows that the planetary spectrum most resembles a blackbody, with no constraint on molecular abundances or vertical temperature variation. WASP-34b is redder than other warm Jupiters with a similar temperature, hinting at unique chemistry, although further observations are necessary to confirm this.

Keywords: exoplanet astronomy; exoplanet atmospheres; light curves; infrared photometry
The CARMA-NRO Orion Survey: Filament Formation via Collision-induced Magnetic Reconnection—the Stick in Orion A

A unique filament is identified in the Herschel maps of the Orion A giant molecular cloud. The filament, which we name the Stick, is ruler-straight and at an early evolutionary stage. Transverse position-velocity diagrams show two velocity components closing in on the Stick. The filament shows consecutive rings/forks in C18O (1-0) channel maps, which is reminiscent of structures generated by magnetic reconnection. We propose that the Stick formed via collision-induced magnetic reconnection (CMR). We use the magnetohydrodynamics code Athena++ to simulate the collision between two diffuse molecular clumps, each carrying an antiparallel magnetic field. The clump collision produces a narrow, straight, dense filament with a factor of >200 increase in density. The production of the dense gas is seven times faster than freefall collapse. The dense filament shows ring/fork-like structures in radiative transfer maps. Cores in the filament are confined by surface magnetic pressure. CMR can be an important dense-gas-producing mechanism in the Galaxy and beyond.

Keywords: molecular clouds; magnetic fields; star formation; interstellar filaments; interstellar medium; giant molecular clouds; millimeter astronomy; computational astronomy; astrophysical fluid dynamics; magnetohydrodynamical simulations; observational astronomy; theoretical models
Inferring Late-stage Enrichment of Exoplanet Atmospheres from Observed Interstellar Comets

The discovery of the first two interstellar objects implies that, on average, every star contributes a substantial amount of material to the galactic population by ejecting such bodies from the host system. Because scattering is a chaotic process, a comparable amount of material should be injected into the inner regions of each system that ejects comets. For comets that are transported inwards and interact with planets, this Letter estimates the fraction of material that is accreted or outward-scattered as a function of planetary masses and orbital parameters. These calculations indicate that planets with escape velocities smaller than their current-day orbital velocities will efficiently accrete comets. We estimate the accretion efficiency for members of the current census of extrasolar planets and find that planetary populations including but not limited to hot and warm Jupiters, sub-Neptunes, and super-Earths can efficiently capture incoming comets. This cometary enrichment may have important ramifications for postformation atmospheric composition and chemistry. As a result, future detections and compositional measurements of interstellar comets will provide direct measurements of material that potentially enriched a subpopulation of the extrasolar planets. Finally, we estimate the efficiency of this enrichment mechanism for extrasolar planets that will be observed with the James Webb Space Telescope (JWST). With JWST currently operational and these observations imminently forthcoming, it is of critical importance to investigate how enrichment from interstellar comet analogs may affect the interpretations of exoplanet atmospheric compositions.

Keywords: interstellar objects; exoplanet atmospheres; comets; galaxy chemical evolution
Tails: Chasing Comets with the Zwicky Transient Facility and Deep Learning

We present Tails, an open-source deep-learning framework for the identification and localization of comets in the image data of the Zwicky Transient Facility (ZTF), a robotic optical time-domain survey currently in operation at the Palomar Observatory in California, USA. Tails employs a custom EfficientDet-based architecture and is capable of finding comets in single images in near real time, rather than requiring multiple epochs as with traditional methods. The system achieves state-of-the-art performance with 99% recall, a 0.01% false-positive rate, and a 1-2 pixel rms error in the predicted position. We report the initial results of the Tails efficiency evaluation in a production setting on the data of the ZTF Twilight survey, including the first AI-assisted discovery of a comet (C/2020 T2) and the recovery of a comet (P/2016 J3 = P/2021 A3).

Keywords: astroinformatics; astronomy data analysis; convolutional neural networks; comets
Systematic Search for Water Fountain Candidates Using the Databases of Circumstellar Maser Sources

Water fountains (WFs) are thought to be objects in the morphological evolution of the circumstellar envelopes of low- and intermediate-mass evolved stars, transitioning from spherically symmetric to asymmetric shapes. We used databases of circumstellar 1612 MHz OH and 22.235 GHz H2O maser sources to search for new WF candidates using the criterion of a larger velocity range of the H2O maser emission compared to that of the OH maser emission. Thus, it is in principle possible to identify WFs with H2O velocity ranges smaller than those for the previously known WFs. For the OH maser line, we analyzed database entries of 8474 observations from 2195 sources, and 6085 observations from 3642 sources for the H2O maser line. After a close examination of the velocity ranges and line profiles, we identified 11 sources that meet the criterion mentioned above. We examined the IRAS colors of the selected sources and found that two of them (IRAS 19069+0916 and IRAS 19319+2214) are in the color region for post-AGB stars. We find that the maser velocity criterion can discover other astrophysically interesting objects than just WFs. Such objects may include peculiar planetary nebulae with maser emissions and stellar merger remnants.

Keywords: circumstellar envelopes; circumstellar masers; asymptotic giant branch; post-asymptotic giant branch stars