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- ID:
- ivo://CDS.VizieR/II/283
- Title:
- Asiago Supernova Catalogue
- Short Name:
- II/283
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue supersedes the previous version by Barbon et al. (1999A&AS..139..531B, Cat. II/227), and contains data about the supernovae observed since 1895 and their parent galaxies until the beginning of 2008. In addition to the list of newly discovered SNe, the literature has been searched for new information on past SNe as well. The data for the parent galaxies have also been homogenized.
- ID:
- ivo://CDS.VizieR/J/MNRAS/506/3540
- Title:
- ASKAP-EMU ESP LMC Radio Continuum Survey
- Short Name:
- J/MNRAS/506/3540
- Date:
- 17 Jan 2022 11:54:41
- Publisher:
- CDS
- Description:
- We present an analysis of a new 120 deg^2^ radio continuum image of the Large Magellanic Cloud (LMC) at 888MHz with a bandwidth of 288MHz and beam size of 13.9"x12.1", from the Australian Square Kilometre Array Pathfinder (ASKAP) processed as part of the Evolutionary Map of the Universe (EMU) survey. The median Root Mean Squared noise is 58uJy/beam. We present a catalogue of 54612 sources, divided over a Gold list (30866 sources) complete down to 0.5mJy uniformly across the field, a Silver list (22080 sources) reaching down to <0.2mJy and a Bronze list (1666 sources) of visually inspected sources in areas of high noise and/or near bright complex emission. We discuss detections of planetary nebulae and their radio luminosity function, young stellar objects showing a correlation between radio luminosity and gas temperature, novae and X-ray binaries in the LMC, and active stars in the Galactic foreground that may become a significant population below this flux level. We present examples of diffuse emission in the LMC (HII regions, supernova remnants, bubbles) and distant galaxies showcasing spectacular interaction between jets and intracluster medium. Among 14333 infrared counterparts of the predominantly background radio source population we find that star-forming galaxies become more prominent below 3mJy compared to active galactic nuclei.We combine the new 888MHz data with archival Australia Telescope Compact Array data at 1.4GHz to determine spectral indices; the vast majority display synchrotron emission but flatter spectra occur too. We argue that the most extreme spectral index values are due to variability.
- ID:
- ivo://CDS.VizieR/J/MNRAS/490/1202
- Title:
- ASKAP EMU ESP, Radio Continuum Survey of the SMC
- Short Name:
- J/MNRAS/490/1202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two new radio continuum images from the Australian Square Kilometre Array Pathnder (ASKAP) survey in the direction of the Small Magellanic Cloud (SMC). These images are part of the Evolutionary Map of the Universe (EMU) Early Science Project (ESP) survey of the Small and Large Magellanic Clouds. The two new source lists produced from these images contain radio continuum sources observed at 960MHz (4489 sources) and 1320MHz (5954 sources) with a bandwidth of 192MHz and beam sizes of 30.0"x30.0" and 16.3"x15.1", respectively. The median Root Mean Squared (RMS) noise values are 186Jy/beam (960MHz) and 165Jy/beam (1320MHz). To create point source catalogues, we use these two source lists, together with the previously published Molonglo Observatory Synthesis Telescope (MOST) and the Australia Telescope Compact Array (ATCA) point source catalogues to estimate spectral indices for the whole population of radio point sources found in the survey region. Combining our ASKAP catalogues with these radio continuum surveys, we found 7736 point-like sources in common over an area of 30deg^2^. In addition, we report the detection of two new, low surface brightness supernova remnant candidates in the SMC. The high sensitivity of the new ASKAP ESP survey also enabled us to detect the bright end of the SMC planetary nebula sample, with 22 out of 102 optically known planetary nebulae showing point-like radio continuum emission. Lastly, we present several morphologically interesting background radio galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/2417
- Title:
- ASK spectroscopic sequence of galaxies
- Short Name:
- J/MNRAS/415/2417
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify a spectroscopic sequence of galaxies, analogous to the Hubble sequence of morphological types, based on the Automatic Spectroscopic K-means-based (ASK) classification. Considering galaxy spectra as multidimensional vectors, the majority of the spectral classes are distributed along a well-defined curve going from the earliest to the latest types, suggesting that the optical spectra of normal galaxies can be described in terms of a single affine parameter. Optically bright active galaxies, however, appear as an independent, roughly orthogonal branch that intersects the main sequence exactly at the transition between early and late types.
- ID:
- ivo://CDS.VizieR/J/A+AS/147/5
- Title:
- AS 78 & MWC 657 spectroscopy
- Short Name:
- J/A+AS/147/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of low- and high-resolution spectroscopic and multicolour photometric observations of two early-type emission-line stars, AS 78 and MWC 657. They were identified by Dong & Hu (1991ChA&A..15..275D) with the IRAS sources 03549+5602 and 22407+6008, respectively, among many other sources displaying a very strong infrared excess, V-[25]>=8mag. AS 78 is recognized as a photometric variable for the first time. A large near-IR excess radiation is detected in AS 78 and confirmed by new, higher-quality, data for MWC 657. Significant variations in the Balmer line profiles are detected for both objects. Modelling of the Balmer line profiles of AS 78 obtained in 1994 yields the following parameters of the star and its wind: T_eff_~17000K, logL_bol_/L_{sun}_~4.0, dM/dt~10^-6^M_{sun}_/yr. The photometric and new spectroscopic data indicate that the star's T_eff_ increases with time, while the stellar wind changes its structure. Distances towards both objects are estimated on the basis of their radial velocities and the galactic rotation curve. Consideration of different options about the nature and evolutionary state of both objects leads us to suggest that they are binary systems containing a B-type intermediate-luminosity star and a gaseous disk around the less luminous component.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A141
- Title:
- A source catalog for the LMC
- Short Name:
- J/A+A/646/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a clean, magnitude-limited (IRAC1 or WISE1<=15.0mag) multiwavelength source catalog for the Large Magellanic Cloud (LMC). The catalog was built by crossmatching (1'') and deblending (3'') between the source list of Spitzer Enhanced Imaging Products (SEIP) and Gaia Data Release 2 (DR2), with strict constraints on the Gaia astrometric solution in order to remove the foreground contamination. It is estimated that about 99.5% of the targets in our catalog are most likely genuine members of the LMC. The catalog contains 197004 targets in 52 different bands, including two ultraviolet, 21 optical, and 29 infrared bands. Additional information about radial velocities and spectral and photometric classifications were collected from the literature. We compare our sample with the sample from Gaia DR2 (2018A&A...616A...1G, Cat. I/345), indicating that the bright end of our sample is mostly comprised of blue helium-burning stars (BHeBs) and red HeBs with inevitable contamination of main sequence stars at the blue end. After applying modified magnitude and color cuts based on previous studies, we identified and ranked 2974 red supergiant, 508 yellow supergiant, and 4786 blue supergiant candidates in the LMC in six color-magnitude diagrams (CMDs). The comparison between the CMDs from the two catalogs of the LMC and Small Magellanic Cloud (SMC) indicates that the most distinct difference appears at the bright red end of the optical and near-infrared CMDs, where the cool evolved stars (e.g., red supergiant stars (RSGs), asymptotic giant branch stars, and red giant stars) are located, which is likely due to the effect of metallicity and star formation history. A further quantitative comparison of colors of massive star candidates in equal absolute magnitude bins suggests that there is essentially no difference for the BSG candidates, but a large discrepancy for the RSG candidates since LMC targets are redder than the SMC ones, which may be due to the combined effect of metallicity on both spectral type and mass-loss rate as well as the age effect. The effective temperatures (Teff) of massive star populations are also derived from reddening-free color of (J-K_S_0. The Teff ranges are 3500<Teff<5000K for an RSG population, 5000<Teff<8000K for a YSG population, and Teff>8000K for a BSG population, with larger uncertainties toward the hotter stars.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A91
- Title:
- A source catalog for the SMC
- Short Name:
- J/A+A/629/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a clean, magnitude-limited (IRAC1 or WISE1 <=15.0mag) multiwavelength source catalog for the Small Magellanic Cloud (SMC) with 45466 targets in total, with the purpose of building an anchor for future studies, especially for the massive star populations at low-metallicity. The catalog contains data in 50 different bands including 21 optical and 29 infrared bands, retrieved from SEIP, VMC, IRSF, AKARI, HERITAGE, Gaia, SkyMapper, NSC, Massey (2002, Cat. II/236), and GALEX, ranging from the ultraviolet to the far-infrared. Additionally, radial velocities and spectral classifications were collected from the literature, and infrared and optical variability statistics were retrieved from WISE, SAGE-Var, VMC, IRSF, Gaia, NSC, and OGLE. The catalog was essentially built upon a 1" crossmatching and a 3" deblending between the Spitzer Enhanced Imaging Products (SEIP) source list and Gaia Data Release 2 (DR2) photometric data. Further constraints on the proper motions and parallaxes from Gaia DR2 allowed us to remove the foreground contamination. We estimate that about 99.5% of the targets in our catalog are most likely genuine members of the SMC. Using the evolutionary tracks and synthetic photometry from MESA Isochrones & Stellar Tracks and the theoretical J-K_S_ color cuts, we identified 1405 red supergiant (RSG), 217 yellow supergiant, and 1,369 blue supergiant candidates in the SMC in five different color-magnitude diagrams (CMDs), where attention should also be paid to the incompleteness of our sample. We ranked the candidates based on the intersection of different CMDs. A comparison between the models and observational data shows that the lower limit of initial mass for the RSG population may be as low as 7 or even 6M_{sun}_ and that the RSG is well separated from the asymptotic giant branch (AGB) population even at faint magnitude, making RSGs a unique population connecting the evolved massive and intermediate stars, since stars with initial mass around 6 to 8$M_{sun}_ are thought to go through a second dredge-up to become AGB stars. We encourage the interested reader to further exploit the potential of our catalog.
- ID:
- ivo://CDS.VizieR/J/AJ/151/144
- Title:
- ASPCAP weights for the 15 APOGEE chemical elements
- Short Name:
- J/AJ/151/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R~22500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using {chi}^2^ minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1dex, and 0.05dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey.
- ID:
- ivo://CDS.VizieR/J/ApJS/234/9
- Title:
- A spectral approach to transit timing variations
- Short Name:
- J/ApJS/234/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The high planetary multiplicity revealed by Kepler implies that transit timing variations (TTVs) are intrinsically common. The usual procedure for detecting these TTVs is biased to long-period, deep transit planets, whereas most transiting planets have short periods and shallow transits. Here we introduce the Spectral Approach technique to TTVs that allows expanding the TTV catalog toward lower TTV amplitude, shorter orbital period, and shallower transit depth. In the spectral approach, we assume that a sinusoidal TTV exists in the data and then calculate the improvement to {chi}^2^ that this model allows over that of the linear-ephemeris model. This enables detection of TTVs even in cases where the transits are too shallow, so that individual transits cannot be timed. The spectral approach is more sensitive because it has fewer free parameters in its model. Using the spectral approach, we (a) detect 129 new periodic TTVs in Kepler data (an increase of ~2/3 over a previous TTV catalog); (b) constrain the TTV periods of 34 long-period TTVs and reduce amplitude errors of known TTVs; and (c) identify cases of multi-periodic TTVs, for which absolute planetary mass determination may be possible. We further extend our analysis by using perturbation theory assuming a small TTV amplitude at the detection stage, which greatly speeds up our detection (to a level of few seconds per star). Our extended TTV sample shows no deficit of short-period or low-amplitude transits, in contrast to previous surveys, in which the detection schemes were significantly biased against such systems.
