Sazuna/UAT_keywords huggingface dataset:
LAMOST Observations in 15 K2 Campaigns. I. Low-resolution Spectra from LAMOST DR6. The Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST)-K2 (LK2) project, initiated in 2015, aims to collect low-resolution spectra of targets in the K2 campaigns, similar to the LAMOST-Kepler project. By the end of 2018, a total of 126 LK2 plates had been observed by LAMOST. After cross-matching the catalog of the LAMOST data release 6 (DR6) with that of the K2 approved targets, we found 160,619 usable spectra of 84,012 objects, most of which had been observed more than once. The effective temperature, surface gravity, metallicity, and radial velocity from 129,974 spectra for 70,895 objects are derived through the LAMOST Stellar Parameter Pipeline (LASP). The internal uncertainties were estimated to be 81 K, 0.15 dex, 0.09 dex, and 5 km s-1, respectively, when derived from a spectrum with a signal-to-noise ratio in the g band (S/Ng) of 10. These estimates are based on results for targets with multiple visits. The external accuracies were assessed by comparing the parameters of targets in common with the APOGEE and Gaia surveys, for which we generally found linear relationships. A final calibration is provided, combining external and internal uncertainties for giants and dwarfs, separately. We foresee that these spectroscopic data will be used widely in different research fields, especially in combination with K2 photometry.

Keywords: Fundamental parameters of stars, Astronomy databases, Catalogs
A Catalog of Broad Morphology of Pan-STARRS Galaxies Based on Deep Learning. Autonomous digital sky surveys such as Pan-STARRS have the ability to image a very large number of galactic and extragalactic objects, and the large and complex nature of the image data reinforces the use of automation. Here we describe the design and implementation of a data analysis process for automatic broad morphology annotation of galaxies, and applied it to the data of Pan-STARRS DR1. The process is based on filters followed by a two-step convolutional neural network (CNN) classification. Training samples are generated by using an augmented and balanced set of manually classified galaxies. Results are evaluated for accuracy by comparison to the annotation of Pan-STARRS included in a previous broad morphology catalog of Sloan Digital Sky Survey galaxies. Our analysis shows that a CNN combined with several filters is an effective approach for annotating the galaxies and removing unclean images. The catalog contains morphology labels for 1,662,190 galaxies with ∼95% accuracy. The accuracy can be further improved by selecting labels above certain confidence thresholds. The catalog is publicly available.

Keywords: Galaxies, Spiral galaxies, Astronomy data analysis, Catalogs
The Wind beneath My Wings. I. Spectral Types and Multiplicity of the Central Stars Supporting Stellar Bow Shock Nebulae. Arcuate mid-infrared nebulae known as stellar bow shock nebulae (SBNe) have been previously hypothesized to be supported by the strong stellar winds and/or luminosity of massive early-type stars. We present an optical spectroscopic survey of 84 stars identified from mid-infrared images as candidate SBN-supporting stars. Eighty-one of 84 sources, 96%, are O or early-B spectral types. K-band luminosities for a larger sample of 289 stars at the centers of bow shock nebulae are overwhelmingly consistent with OB stars. This affirms both that SBNe are supported by massive stars and that arcuate mid-infrared nebulae are reliable indicators of the presence of a massive star. The radial velocity dispersions of these systems and detections of double-lined systems indicate that at least 27 of the 74 systems with multiple observations (&gt;36%) are candidate multiple-star systems. This rate is consistent with observed multiplicity rates of field OB stars detected with similar radial velocity surveys and lower than, but not inconsistent with, the multiplicity rates of OB stars in clusters and associations.

Keywords: Stellar-interstellar interactions, B stars, O stars, Stellar wind bubbles, Dust nebulae, Massive stars, Stellar bow shocks, Interstellar medium, Runaway stars
Estimating Statistical Uncertainties of Internal Kinematics of Galaxies and Star Clusters Derived Using Full Spectrum Fitting. Pixel-space full spectrum fitting exploiting nonlinear χ2 minimization became a de facto standard way of deriving internal kinematics from absorption line spectra of galaxies and star clusters. However, reliable estimation of uncertainties for kinematic parameters remains a challenge and is usually addressed by running computationally expensive Monte-Carlo simulations. Here we derive simple formulae for the radial velocity and velocity dispersion uncertainties based solely on the shape of a template spectrum used in the fitting procedure and signal-to-noise information. Comparison with Monte-Carlo simulations provides agreement within a few per cent for different templates, signal-to-noise ratios and input velocity dispersions between 0.5 and 10 times the instrumental spectral resolution. For moderate template mismatch our technique returns uncertainties consistent within 20%-30% with those reported by Monte-Carlo simulations. We provide IDL and PYTHON implementations of our approach. The main applications are: (i) exposure time calculators; (ii) design of observational programs and estimates on expected uncertainties for spectral surveys of galaxies and star clusters; (iii) a cheap and accurate substitute for Monte-Carlo simulations when running them for large samples of thousands of spectra is unfeasible.

Keywords: Analytical mathematics, Galaxy dynamics, Galaxy kinematics, Astronomy data analysis
OASI: A Brazilian Observatory Dedicated to the Study of Small Solar System Bodies—Some Results on NEO's Physical Properties. The distribution of professional observatories around the world is quite biased toward the Northern Hemisphere, and this tendency is even more pronounced when considering those dedicated only to the study of small solar system bodies. In the Southern Hemisphere, the IMPACTON project deployed the Observatório Astronômico do Sertão de Itaparica (OASI), dedicated to the observation of minor bodies of the solar system with emphasis on Near-Earth Objects (NEOs). The observatory is located at the county of Itacuruba, in the Pernambuco State of Brazil, and operate a 1 m Cassegrain telescope. Here, we present a complete characterization of the OASI instruments and the sky conditions during the first eight years of operations. The limiting magnitudes are determined in the different available filters. The median seeing results to be 1"22, with a higher number of photometric nights from April to October. We also give an overview of the results obtained from the OASI observations and discuss them in the light of similar data from the literature. In particular, the rotational periods of 23 NEOs, and the spin directions and shapes of 9 NEOs, have been determined for the very first time using our observations. Analyzing rotational periods, sizes and taxonomic classification from the literature and OASI, we conclude that the fast rotating NEOs are predominantly S-type objects. However, rotational periods obtained at the OASI and with similar value from LCDB database allowed to identify the first fast rotator C-type NEO: asteroid 436724. With an estimated tensile strength as low as 0.5 KPa, this asteroid allows us to suggest that it defines the border between the C- and S-type fast rotators in the size versus period diagram. Although this hypothesis is based on a very small sample it is compatible with all presently available data. Only new observations, however, can prove if this hypothesis is correct.

Keywords: Surveys, Near-Earth objects, Telescopes
A Gaia Early DR3 Mock Stellar Catalog: Galactic Prior and Selection Function. We present a mock stellar catalog, matching in volume, depth and data model the content of the planned Gaia early data release 3 (Gaia EDR3). We have generated our catalog (GeDR3mock) using galaxia, a tool to sample stars from an underlying Milky Way (MW) model or from N-body data. We used an updated Besançon Galactic model together with the latest PARSEC stellar evolutionary tracks, now also including white dwarfs. We added the Magellanic clouds and realistic open clusters with internal rotation. We empirically modeled uncertainties based on Gaia DR2 (GDR2) and scaled them according to the longer baseline in Gaia EDR3. The apparent magnitudes were reddened according to a new selection of 3D extinction maps. To help with the Gaia selection function we provide all-sky magnitude limit maps in G and BP for a few relevant GDR2 subsets together with the routines to produce these maps for user-defined subsets. We supplement the catalog with photometry and extinctions in non-Gaia bands. The catalog is available in the Virtual Observatory (http://dc.g-vo.org/tableinfo/gedr3mock.main) and can be queried just like the actual Gaia EDR3 will be. We highlight a few capabilities of the Astronomy Data Query Language with educative catalog queries. We use the data extracted from those queries to compare GeDR3mock to GDR2, which emphasises the importance of adding observational noise to the mock data. Since the underlying truth, e.g., stellar parameters, is know in GeDR3mock, it can be used to construct priors as well as mock data tests for parameter estimation. All code, models and data used to produce GeDR3mock are linked and contained in galaxia_wrap (https://github.com/jan-rybizki/Galaxia_wrap), a python package, representing a fast galactic forward model, able to project MW models and N-body data into realistic Gaia observables.

Keywords: Stellar evolutionary models, Interstellar dust extinction, Virtual observatories, Open star clusters, Milky Way Galaxy
Brighter-fatter Effect in Near-infrared Detectors—III. Fourier-domain Treatment of Flat Field Correlations and Application to WFIRST. Weak gravitational lensing has emerged as a leading probe of the growth of cosmic structure. However, the shear signal is very small and accurate measurement depends critically on our ability to understand how non-ideal instrumental effects affect astronomical images. The Wide-Field Infrared Survey Telescope (WFIRST) will fly a focal plane containing 18 Teledyne H4RG-10 near-infrared detector arrays, which present different instrument calibration challenges from previous weak lensing observations. Previous work [Paper I: Hirata &amp; Choi, PASP, 132, 014501 (2020); and Paper II: Choi &amp; Hirata, PASP, 132, 014502 (2020)] has shown that correlation functions of flat field images, including cross-correlations between different time slices that are enabled by the non-destructive read capability of the infrared detectors, are effective tools for disentangling linear and nonlinear inter-pixel capacitance (IPC) and the brighter-fatter effect (BFE). Here we present a Fourier-domain treatment of the flat field correlations, which allows us to expand the previous formalism to all orders in IPC, BFE, and classical nonlinearity. We show that biases in simulated flat field analyses in Paper I are greatly reduced through the use of this formalism. We then apply this updated formalism to flat field data from three WFIRST flight candidate detectors, and explore the robustness to variations in the analysis. We find that the BFE is present in all three detectors, and that its contribution to the flat field correlations dominates over the nonlinear IPC, in accordance with the results from Paper II on a development detector. The magnitude of the BFE is such that the effective area of a pixel is increased by (3.54 ± 0.03) × 10-7 for every electron deposited in a neighboring pixel (sensor chip assembly [SCA] 20829, statistical error, not IPC-deconvolved). We compare IPC maps from flat field autocorrelation measurements to those obtained from the single pixel reset method and find a median difference of 0.113% for SCA 20829. After further diagnosis of this difference, we ascribe it largely to an additional source of cross-talk, the vertical trailing pixel effect, and recommend further work to develop a model for this effect. These results represent a significant step toward calibration of the non-ideal effects in WFIRST detectors.

Keywords: Astronomical instrumentation
Herschel Observations of Disks around Late-type Stars. A set of twenty late-type (K5-M5) stars were observed with the Herschel Space Observatory at 100 and 160 microns with the goal of searching for far-infrared excesses indicative of the presence of circumstellar disks. Out of this sample, four stars (TYC 7443-1102-1, TYC 9340-437-1, GJ 784 and GJ 707) have infrared excesses above their stellar photospheres at either 100 or 160 μm or both. At 100 microns TYC 9340-437-1 is spatially resolved with a shape that suggests it is surrounded by a face-on disk. The 100 μm excess flux associated with GJ 707 is marginal at around 3σ. The excess flux associated with GJ 784 is most likely due to a background galaxy as the dust radius estimated from the spectral energy fit implies that any associated dust disk should have been resolved in the Herschel images but is not. TYC 7443-1102-1 has been observed with ALMA which resolves the emission at its location into two distinct sources making the Herschel excess most likely also due to a background galaxy. It is worth noting that this star is in the 23 Myr old β Pic association. With a disk luminosity on the order of 10-3 L*, this system is an ideal follow-up target for high-contrast imaging and ALMA.

Keywords: Late-type stars, Circumstellar disks
Forecasting Rates of Volcanic Activity on Terrestrial Exoplanets and Implications for Cryovolcanic Activity on Extrasolar Ocean Worlds. Like the planets and moons in our solar system, the surfaces of terrestrial exoplanets may be shaped by volcanic activity. The magnitudes and rates of volcanic activity on terrestrial exoplanets will be intimately linked to their sizes and internal heating rates and can either facilitate or preclude the existence of habitable environments. In order to place bounds on the potential for such activity, we estimate total internal heating rates for 53 exoplanets with masses and radii up to ∼8M⊕ and 2R⊕, respectively, assuming that internal heating is drawn from both radiogenic and tidal sources. We then compare these internal heating rates to those of the planets and moons in our solar system in an attempt to constrain the expected rates of volcanic activity on these extrasolar worlds. We find that all 53 of the exoplanets surveyed are likely to have volcanic activity at their surfaces, and that at least 26% of these planets may be extrasolar ocean worlds. The majority of these ocean worlds may be similar in structure to the icy moons of the giant planets, having internal oceans beneath layers of surface ice. If so, these planets may exhibit cryovolcanism (i.e., icy volcanism) at their surfaces. Recent studies have shown that extrasolar volcanism could be detected by high-resolution spectrographs on existing ground-based telescopes. In the case of planets with densities and/or effective temperatures that are consistent with H2O-rich compositions, spectral identification of excess water vapor and other molecules that are explosively vented into space during cryovolcanic eruptions could serve as a way to infer the presence of subsurface oceans, and therefore indirectly assess their habitability. Considering the implications for habitability, our results suggest that continued characterization of terrestrial exoplanets in terms of their potential for volcanic activity should be a priority in the coming years.

Keywords: Extrasolar rocky planets, Tidal friction, Ocean planets, Exoplanets, Exosphere, Exoplanet surface characteristics, Volcanoes, Exoplanet structure, Exoplanet atmospheres
A Simple Method to Estimate the Refractive Index Structure Parameter ( {C}_{n}(2) ) in the Atmosphere. This paper proposes a simple physics-based method for estimating the ${C}_{n}^{2}$ profile in the lower atmosphere, using the Ellison scale as a measure of the outer turbulence scale. The new approach only Requires the temperature profile as an input to obtain the profile of the outer turbulence scale, followed by the ${C}_{n}^{2}$ profile. Using sounding data from Lhasa (Tibet) ${C}_{n}^{2}$ profiles were estimated using three outer scale models (Thorpe, HMNSP99, and Ellison) and compared with the measured ${C}_{n}^{2}$ profile. Results show that the Ellison scale method offers better results as a profile estimator than the other two methods. Compared with the measured ${C}_{n}^{2}$ profile, the average relative error of the Ellison scale method is generally lower than 8%, with a correlation coefficient larger than 0.5.

Keywords: Atmospheric effects, Atmospheric refraction
Simulations of ELT-GMCAO Performance for Deep Field Observations. The Global-Multi Conjugated Adaptive Optics (GMCAO) approach offers an alternative way to correct an adequate scientific Field of View (FoV) using only natural guide stars (NGSs) to extremely large ground-based telescopes. Thus, even in the absence of laser guide stars, a GMCAO-equipped ELT-like telescope can achieve optimal performance in terms of Strehl Ratio (SR), retrieving impressive results in studying star-poor fields, as in the cases of the deep field observations. The benefits and usability of GMCAO have been demonstrated by studying 6000 mock high redshift galaxies in the Chandra Deep Field South region. However, a systematic study simulating observations in several portions of the sky is mandatory to have a robust statistic of the GMCAO performance. Technical, tomographic and astrophysical parameters, discussed here, are given as inputs to GIUSTO, an IDL-based code that estimates the SR over the considered field, and the results are analyzed with statistical considerations. The best performance is obtained using stars that are relatively close to the Scientific FoV; therefore, the SR correlates with the mean off-axis position of NGSs, as expected, while their magnitude plays a secondary role. This study concludes that the SRs correlate linearly with the galactic latitude, as also expected. Because of the lack of natural guide stars needed for low-order aberration sensing, the GMCAO confirms as a promising technique to observe regions that can not be studied without the use of laser beacons. It represents a robust alternative way or a risk mitigation strategy for laser approaches on the ELTs.

Keywords: Laser guide stars, Astronomical techniques, Ground-based astronomy, High-redshift galaxies, Astronomical methods, Galaxies
A Low Cost 4 bit 16 Giga-sample-per-second Analog-to-digital Converter for Radio Astronomy. In this study, a 4 bit, 16 giga samples per second analog-to-digital converter (ADC) printed circuit board assembly (PCBA) was designed, manufactured, and characterized for digitizing signals from radio telescopes. For this purpose, an Adsantec ANST7123-KMA flash ADC chip was used. Because this design of chip is not followed the serial ADC JESD204 standard completely, we used a novel channel bonding scheme developed in our previous project for the high-speed serial data input alignment. The PCBA was equipped with a field-programmable gate array (FPGA) mezzanine card (FMC) connector. FMC allowed us to use the FPGA evaluation board by Xilinx as the testing platform. The PCBA enables data acquisition with a wide bandwidth and simplifies the intermediate frequency section. In the current version, the PCBA and the chip exhibit an analog bandwidth of 16 GHz, which facilitates a second Nyquist sampling. The following minimum to maximum performance parameters were obtained from the first and second Nyquist zones: a spurious-free dynamic range of 18-33 dB and an effective number of bits of 2.1-3.7 bits. The board will be ported to the Collaboration for Astronomy Signal Processing and Electronics Research environment, which is open for use by non-profit scientific teams, including the Event Horizon Telescope.

Keywords: Radio astronomy
Design and Operation of the ATLAS Transient Science Server. The Asteroid Terrestrial impact Last Alert System (ATLAS) system consists of two 0.5 m Schmidt telescopes with cameras covering 29 square degrees at plate scale of 1.86 arcsec per pixel. Working in tandem, the telescopes routinely survey the whole sky visible from Hawaii (above $\delta \gt -50^\circ $ ) every two nights, exposing four times per night, typically reaching $o\lt 19$ magnitude per exposure when the moon is illuminated and $c\lt 19.5$ magnitude per exposure in dark skies. Construction is underway of two further units to be sited in Chile and South Africa which will result in an all-sky daily cadence from 2021. Initially designed for detecting potentially hazardous near earth objects, the ATLAS data enable a range of astrophysical time domain science. To extract transients from the data stream requires a computing system to process the data, assimilate detections in time and space and associate them with known astrophysical sources. Here we describe the hardware and software infrastructure to produce a stream of clean, real, astrophysical transients in real time. This involves machine learning and boosted decision tree algorithms to identify extragalactic and Galactic transients. Typically we detect 10-15 supernova candidates per night which we immediately announce publicly. The ATLAS discoveries not only enable rapid follow-up of interesting sources but will provide complete statistical samples within the local volume of 100 Mpc. A simple comparison of the detected supernova rate within 100 Mpc, with no corrections for completeness, is already significantly higher (factor 1.5 to 2) than the current accepted rates.

Keywords: Asteroids, Surveys, Variable stars, Supernovae
Solar System Physics for Exoplanet Research. Over the past three decades, we have witnessed one of the great revolutions in our understanding of the cosmos—the dawn of the Exoplanet Era. Where once we knew of just one planetary system (the solar system), we now know of thousands, with new systems being announced on a weekly basis. Of the thousands of planetary systems we have found to date, however, there is only one that we can study up-close and personal—the solar system. In this review, we describe our current understanding of the solar system for the exoplanetary science community—with a focus on the processes thought to have shaped the system we see today. In section one, we introduce the solar system as a single well studied example of the many planetary systems now observed. In section two, we describe the solar system's small body populations as we know them today—from the two hundred and five known planetary satellites to the various populations of small bodies that serve as a reminder of the system's formation and early evolution. In section three, we consider our current knowledge of the solar system's planets, as physical bodies. In section four we discuss the research that has been carried out into the solar system's formation and evolution, with a focus on the information gleaned as a result of detailed studies of the system's small body populations. In section five, we discuss our current knowledge of planetary systems beyond our own—both in terms of the planets they host, and in terms of the debris that we observe orbiting their host stars. As we learn ever more about the diversity and ubiquity of other planetary systems, our solar system will remain the key touchstone that facilitates our understanding and modeling of those newly found systems, and we finish section five with a discussion of the future surveys that will further expand that knowledge.

Keywords: Solar system formation, Small Solar System bodies, Exoplanets, Solar system planets, Planetary science, Solar system astronomy