Search

Start Over Subject surveys Rights public
1731. 76 T dwarfs from the UKIDSS LAS
ID:
ivo://CDS.VizieR/J/MNRAS/433/457
Title:
76 T dwarfs from the UKIDSS LAS
Short Name:
J/MNRAS/433/457
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Near-infrared broad- and narrow-band photometry and spectroscopy are presented for the new objects, along with Wide-field Infrared Survey Explorer (WISE) and warm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H-[4.5] and J-W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in Teff when considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.
1732. Teff and metallicities of M dwarfs in APOGEE DR14
ID:
ivo://CDS.VizieR/J/ApJ/892/31
Title:
Teff and metallicities of M dwarfs in APOGEE DR14
Short Name:
J/ApJ/892/31
Date:
07 Mar 2022 13:23:27
Publisher:
CDS
Description:
M dwarfs have enormous potential for our understanding of structure and formation on both Galactic and exoplanetary scales through their properties and compositions. However, current atmosphere models have limited ability to reproduce spectral features in stars at the coolest temperatures (Teff<4200K) and to fully exploit the information content of current and upcoming large-scale spectroscopic surveys. Here we present a catalog of spectroscopic temperatures, metallicities, and spectral types for 5875 M dwarfs in the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and Gaia-DR2 surveys using The Cannon (Ness+ 2015, J/ApJ/808/16 ; Casey+ 2016, arXiv:1603.03040; Ho+ 2017, J/ApJ/836/5; Behmard+ 2019ApJ...876...68B): a flexible, data-driven spectral-modeling and parameter-inference framework demonstrated to estimate stellar-parameter labels (Teff, logg, [Fe/H], and detailed abundances) to high precision. Using a training sample of 87 M dwarfs with optically derived labels spanning 2860K<Teff<4130K calibrated with bolometric temperatures, and -0.5<[Fe/H]<0.5dex calibrated with FGK binary metallicities, we train a two-parameter model with predictive accuracy (in cross-validation) to 77K and 0.09dex respectively. We also train a one-dimensional spectral classification model using 51 M dwarfs with Sloan Digital Sky Survey optical spectral types ranging from M0 to M6, to predictive accuracy of 0.7 types. We find Cannon temperatures to be in agreement to within 60 K compared to a subsample of 1702 sources with color-derived temperatures, and Cannon metallicities to be in agreement to within 0.08 dex metallicity compared to a subsample of 15 FGK+M or M+M binaries. Finally, our comparison between Cannon and APOGEE pipeline (ASPCAP DR14) labels finds that ASPCAP is systematically biased toward reporting higher temperatures and lower metallicities for M dwarfs.
1733. TESS-HERMES Survey Data Release 1 catalog
ID:
ivo://CDS.VizieR/J/MNRAS/473/2004
Title:
TESS-HERMES Survey Data Release 1 catalog
Short Name:
J/MNRAS/473/2004
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Transiting Exoplanet Survey Satellite (TESS) will provide high-precision time series photometry for millions of stars with at least a half-hour cadence. Of particular interest are the circular regions of 12{deg} radius centred around the ecliptic poles that will be observed continuously for a full year. Spectroscopic stellar parameters are desirable to characterize and select suitable targets for TESS, whether they are focused on exploring exoplanets, stellar astrophysics or Galactic archaeology. Here, we present spectroscopic stellar parameters (Teff, logg, [Fe/H], vsini, vmicro) for about 16000 dwarf and subgiant stars in TESS' southern continuous viewing zone. For almost all the stars, we also present Bayesian estimates of stellar properties including distance, extinction, mass, radius and age using theoretical isochrones. Stellar surface gravity and radius are made available for an additional set of roughly 8500 red giants. All our target stars are in the range 10<V<13.1. Among them, we identify and list 227 stars belonging to the Large Magellanic Cloud. The data were taken using the High Efficiency and Resolution Multi-Element Spectrograph (HERMES; R~28000) at the Anglo-Australian Telescope as part of the TESS-HERMES survey. Comparing our results with the TESS Input Catalogue (TIC) shows that the TIC is generally efficient in separating dwarfs and giants, but it has flagged more than 100 cool dwarfs (Teff<4800K) as giants, which ought to be high-priority targets for the exoplanet search. The catalogue can be accessed via http://www.physics.usyd.edu.au/tess-hermes/, or at Mikulski Archive for Space Telescopes (MAST).
1734. TESS predicted yield of transits
ID:
ivo://CDS.VizieR/J/PASP/131/C4401
Title:
TESS predicted yield of transits
Short Name:
J/PASP/131/C4401
Date:
21 Oct 2021
Publisher:
CDS
Description:
Radial velocity (RV) surveys have detected hundreds of exoplanets through their gravitational interactions with their host stars. Some will be transiting, but most lack sufficient follow-up observations to confidently detect (or rule out) transits. We use published stellar, orbital, and planetary parameters to estimate the transit probabilities for nearly all exoplanets that have been discovered via the RV method. From these probabilities, we predict that 25.5_-0.7_^+0.7^ of the known RV exoplanets should transit their host stars. This prediction is more than double the amount of RV exoplanets that are currently known to transit. The Transiting Exoplanet Survey Satellite (TESS) presents a valuable opportunity to explore the transiting nature of many of the known RV exoplanet systems. Based on the anticipated pointing of TESS during its two-year primary mission, we identify the known RV exoplanets that it will observe and predict that 11.7_-0.3_^+0.3^ of them will have transits detected by TESS. However, we only expect the discovery of transits for ~3 of these exoplanets to be novel (i.e., not previously known). We predict that the TESS photometry will yield dispositive null results for the transits of ~125 RV exoplanets. This will represent a substantial increase in the effort to refine ephemerides of known RV exoplanets. We demonstrate that these results are robust to changes in the ecliptic longitudes of future TESS observing sectors. Finally, we consider how several potential TESS extended mission scenarios affect the number of transiting RV exoplanets we expect TESS to observe.
1735. Texas-Oxford NVSS (TONS) radio galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/357/1231
Title:
Texas-Oxford NVSS (TONS) radio galaxies
Short Name:
J/MNRAS/357/1231
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a clustering analysis of the Texas-Oxford NVSS Structure (TONS) radio galaxy redshift survey. This complete flux-limited survey consists of 268 radio galaxies with spectroscopic redshifts in three separate regions of the sky covering a total of 165{deg}^2^. By going to faint radio flux densities (S_1.4_>=3mJy) but imposing relatively bright optical limits (E~R~19.5), the TONS sample is optimized for looking at the clustering properties of low-luminosity radio galaxies in a region of moderate (0<=z<=0.5) redshifts. Description:
1736. The AC 2000.2 Catalogue
ID:
ivo://CDS.VizieR/I/275
Title:
The AC 2000.2 Catalogue
Short Name:
I/275
Date:
21 Oct 2021
Publisher:
CDS
Description:
The AC 2000.2 is a revised version of the 1997 release of the AC 2000 (Cat. <I/247>). It was decided that the availability of an improved reference catalogue and the inclusion of photometry from the Tycho-2 catalogue would be sufficient to warrant a complete re-reduction of the data and a new distribution of the catalogue. The AC 2000.2 catalog contains positions of 4,621,751 stars at the average epoch of plate exposures for each star (average 1907).
1737. The AC2000 Catalogue
ID:
ivo://CDS.VizieR/I/247
Title:
The AC2000 Catalogue
Short Name:
I/247
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Astrographic Catalogue (AC) was an international effort designed to photograph and measure the positions of all stars brighter than magnitude 11.0. In total, some 4.6 million stars were observed, many as faint as 13th magnitude. Users should realize that a few thousand of the brightest stars are not included; their images on the source plates were grossly over-exposed and therefore measurements were often not made. This project was started over 100 years ago, and the positions that have been derived from the AC data are being used, in combination with modern epoch positions, to determine accurate proper motions. The United States Naval Observatory has completed the reductions of the Astrographic Catalogue data (AC) to a consistent system. The resulting catalog, called AC 2000, contains 4,621,836 stars covering the entire sky, at an average epoch of 1907. The positions are on the Hipparcos reference frame (J2000.0) at the epochs of observation. Each of the 22 zones making up the Astrographic Catalogue was reduced independently using the Astrographic Catalog Reference Stars (ACRS). Each was analyzed for tilt, radial and tangential distortions, coma, magnitude equation and non-symmetric field distortions. Following these reductions, the data were placed on the Hipparcos system and the magnitudes were converted to be close to that of the Tycho B data. The resulting data were then combined into the final catalog. Detailed information on the reduction methodology and input data can be found in the file "intro.tex", or in the postscript documents provided provided in the "ps" subdirectory. The data contain the positions (eq. J2000.0) at mean epochs of observation, magnitude estimates and accuracy estimates for each star. Cross identifications with the Hipparcos Catalogue, Tycho Catalogue and the Astrographic Catalog Reference Stars are provided to facilitate future work with these stars. Interested parties are encouraged to visit the AC web site at http://aries.usno.navy.mil/ad/ac.html.
1738. The ACS-GC catalog
ID:
ivo://CDS.VizieR/J/ApJS/200/9
Title:
The ACS-GC catalog
Short Name:
J/ApJS/200/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Advanced Camera for Surveys General Catalog (ACS-GC), a photometric and morphological database using publicly available data obtained with the Advanced Camera for Surveys (ACS) instrument on the Hubble Space Telescope. The goal of the ACS-GC database is to provide a large statistical sample of galaxies with reliable structural and distance measurements to probe the evolution of galaxies over a wide range of look-back times. The ACS-GC includes approximately 470000 astronomical sources (stars + galaxies) derived from the AEGIS, COSMOS, GEMS, and GOODS surveys. Galapagos code (Hausler et al. 2011ASPC..442..155H) was used to construct photometric (SExtractor) and morphological (Galfit) catalogs. The analysis assumes a single Sersic model for each object to derive quantitative structural parameters. We include publicly available redshifts from the DEEP2, COMBO-17, TKRS, PEARS, ACES, CFHTLS, and zCOSMOS surveys to supply redshifts (spectroscopic and photometric) for a considerable fraction (~74%) of the imaging sample. The ACS-GC includes color postage stamps, Galfit residual images, and photometry, structural parameters, and redshifts combined into a single catalog.
1739. The ACT Reference Catalog
ID:
ivo://CDS.VizieR/I/246
Title:
The ACT Reference Catalog
Short Name:
I/246
Date:
21 Oct 2021
Publisher:
CDS
Description:
The U.S. Naval Observatory has completed the compilation of the ACT Reference Catalog, containing 988,758 stars covering the entire sky. The motivation behind the ACT was to provide accurate proper motions for the majority of the stars in the Tycho Catalogue (ESA SP-1200). To do this, positions from new reductions of the Astrographic Catalogue (AC 2000) were combined with those of Tycho. The large epoch span between the two catalogs yields proper motions about an order of magnitude more accurate than those published in the Tycho Catalogue. The astrometric data contained in the ACT Reference Catalog include positions, proper motions and error estimates. These are on the Hipparcos System (J2000.0) for epoch J2000.0. Photometric data (B and V) from Tycho are included. Additionally, cross references to the Tycho, AC 2000, Bonner Durchmusterung (BD), Cordoba Durchmusterung (CD), Cape Durchmusterung (CPD), Henry Draper (HD) and Hipparcos Catalogues are given.
1740. The Allen Telescope Array 20cm Survey (ATATS). I.
ID:
ivo://CDS.VizieR/VIII/87
Title:
The Allen Telescope Array 20cm Survey (ATATS). I.
Short Name:
VIII/87
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Allen Telescope Array Twenty-centimeter Survey (ATATS), a multi-epoch (12 visits), 690deg^2^ radio image and catalog at 1.4GHz. The survey is designed to detect rare, very bright transients as well as to verify the capabilities of the ATA to form large mosaics. The combined image using data from all 12 ATATS epochs has rms noise {sigma}=3.94mJy/beam and dynamic range 180, with a circular beam of 150" FWHM. It contains 4408 sources to a limiting sensitivity of 5{sigma}=20mJy/beam. We compare the catalog generated from this 12 epoch combined image to the NRAO VLA Sky Survey (NVSS), a legacy survey at the same frequency, and find that we can measure source positions to better than ~20". For sources above the ATATS completeness limit, the median flux density is 97% of the median value for matched NVSS sources, indicative of an accurate overall flux calibration. We examine the effects of source confusion due to the effects of differing resolution between ATATS and NVSS on our ability to compare flux densities. We detect no transients at flux densities greater than 40mJy in comparison with NVSS and place a 2{sigma} upper limit of 0.004deg^-2^ on the transient rate for such sources. These results suggest that the >~1Jy transients reported by Matsumara et al. may not be true transients, but rather variable sources at their flux density threshold.