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651. Tycho Input Catalogue, Revised version
ID:
ivo://CDS.VizieR/I/197A
Title:
Tycho Input Catalogue, Revised version
Short Name:
I/197A
Date:
21 Oct 2021
Publisher:
CDS
Description:
A Tycho Input Catalogue of three million stars brighter than V=12.1 has been prepared, for the needs of the Tycho mission (Hipparcos satellite). This catalogue results from the cross-matching of a subset of the Hubble Space Telescope Guide Star Catalog with the Hipparcos INCA database. References to these major catalogues, and details about the cross-matching procedures are to be found in the paper published in Astron. Astrophys. 258, 217-222 (May 1992). Among the 3,154,204 stars of the Tycho Input Catalogue, only a bit more than 1 million will appear in the final Tycho catalogue. A preliminary selection was done in the Recognition process, that was based on the first year of the satellite scientific mission (Halbwachs et al., =1994A&A...281L..25H). 1,049,971 stars were thus selected, and are flagged in this version of the Tycho Input Catalogue. The main file contains 3 154 204 records of 80 characters (total size: 256 Mbytes). It is split into four files tic1 to tic4 for easier manipulations. An annex file contains the following additional data for a subset of the stars: (a) the cross-identification with the Hipparcos Input Catalogue (117 778 records, flag 26) (b) the cross-matching with the INCA database (217 625 records, flag 20). The annex file contains 217 625 records (64 char., 14 Mbytes).
652. UBV photometry in Ruprecht 106
ID:
ivo://CDS.VizieR/J/AJ/100/1811
Title:
UBV photometry in Ruprecht 106
Short Name:
J/AJ/100/1811
Date:
21 Oct 2021
Publisher:
CDS
Description:
UBV CCD photometry for about 2500 stars in the Galactic globular cluster Ruprecht 106 has been performed yielding the first color-magnitude diagram (CMD) for this object. The CMD extends down to about 2 mag fainter than the main-sequence turnoff (TO). The cluster possesses a remarkably flat horizontal branch which lies completely to the red of the instability strip. From the analysis of the CMD the following basic parameters have been determined: [Fe/H] = -1.09 and primordial helium abundance Yp = 0.20 0.05. A sizable, highly centrally concentrated population of blue stragglers has also been detected. The location and morphology of the mean ridge lines in the CMD of Ruprecht 106 have then been differentially compared with that of the metal-rich cluster 47 Tuc, NGC 362, a cluster of intermediate metallicity, and with two well-studied metal-poor clusters, M68 and NGC 6397. Significant differences in the positions of the TOs are apparent in the comparison with the metal-poor clusters. These differences can be explained if Ruprecht 106 is 4-5 Gyr younger than NGC 6397 and M68, although alternative, less straightforward explanations cannot be ruled out. The horizontal branch morphology fits perfectly into this picture using models with non-solar-scaled abundances ([O/Fe]>0.5), showing that two second parameters are at work in this cluster, i.e., age (the dominant) and O enhancement. If these findings are confirmed, Ruprecht 106 will turn out to be the first young metal-poor Galactic globular cluster discovered, with quite strong implications for the study of the collapse and enrichment of the Galactic halo.
653. UCAC2 Catalogue
ID:
ivo://CDS.VizieR/I/289
Title:
UCAC2 Catalogue
Short Name:
I/289
Date:
21 Oct 2021
Publisher:
CDS
Description:
The UCAC2 is the second release of the ongoing UCAC project, designed to observe the entire sky for R magnitudes of about 7.5 to 16. The observed positional errors are about 20 mas for the stars in the 10-14 magnitude range, and about 70 mas at the limiting magnitude of R~16. For up-to-date information on the project, see the UCAC web page at http://ad.usno.navy.mil/ucac/ . This web page will also serve as the location that the UCAC team will post addenda to the UCAC2 catalog. The UCAC2 is a high density, highly accurate, astrometric catalog of 48,330,571 stars covering the sky from -90 to +40 degrees in declination and going up to +52 degrees in some areas. The northern limit is a function of right ascension. Proper motions and photometry are provided for all stars. Positions and proper motions are on the ICRS (International Celestial Reference System) and given at the epoch J2000.0. The UCAC2 has a number of major differences with respect to UCAC1. These differences include: - much larger sky coverage - reduced systematic errors of CCD observations - positions given at a standard epoch (J2000.0) - the addition of several new catalogs for improved proper motions - photometry in the J, H, and K_s bands from the 2MASS project Additional details of the data are found in Sections 3, 4, and 5 of the "readme.txt" file. UCAC2 is the last intermediate data release before the final, all sky catalog will be constructed. Observations will end around mid 2004; the final catalog is expected out in 2005. The UCAC project, observations, and first data release are described in detail in the paper Zacharias et al. AJ 120, 2131 (2000). Versions of that and other related papers are placed on the UCAC Web page (http://ad.usno.navy.mil/ucac/). The paper describing UCAC2 is in preparation (AJ, 2003); some further details can be found in the "readme.txt" file.
654. UCAC1 Catalogue
ID:
ivo://CDS.VizieR/I/268
Title:
UCAC1 Catalogue
Short Name:
I/268
Date:
21 Oct 2021
Publisher:
CDS
Description:
The UCAC1 is a high density, highly accurate, astrometric catalog of over 27 million stars in the Southern Hemisphere in the magnitude range of about 8 to 16. This version is the first release of an ongoing project to observe the entire sky; for up-to-date information see the Web page at http://ad.usno.navy.mil/ad/ucac/ . The UCAC1 is a preliminary catalog. By avoiding all "problem cases" (see details in the "intro.txt" file) it is not complete. Positions, proper motions and errors are provided, together with approximate magnitudes in the 579-642nm range. The positional precision is about 20 mas for 9 to 14 mag and 70 mas at 16th mag. The errors of the proper motions are very heterogeneous, ranging from 1 to 35 mas/yr. The UCAC is an observational program using the U.S. Naval Observatory Twin Astrograph and a 4kx4k CCD camera, covering just over 1 square degree per frame with a scale of 0.9"/pixel. Observations started in January 1998 at Cerro Tololo Interamerican Observatory (CTIO) and are continuing. This first catalog contains data observed through 07 November 1999 at which time about 80% of the Southern Hemisphere was completed. Full sky coverage is expected by early 2003 after a re-location of the instrument to the Northern Hemisphere planned for early 2001. The UCAC1 is also available on CD-ROM from the US Naval Observatory. Direct request to nz@pisces.usno.navy.mil with UCAC1 in the subject string.
655. UCAC4 Catalogue
ID:
ivo://CDS.VizieR/I/322A
Title:
UCAC4 Catalogue
Short Name:
I/322A
Date:
21 Oct 2021
Publisher:
CDS
Description:
UCAC4 is a compiled, all-sky star catalog covering mainly the 8 to 16 magnitude range in a single bandpass between V and R. Positional errors are about 15 to 20 mas for stars in the 10 to 14 mag range. Proper motions have been derived for most of the about 113 million stars utilizing about 140 other star catalogs with significant epoch difference to the UCAC CCD observations. These data are supplemented by 2MASS photometric data for about 110 million stars and 5-band (B,V,g,r,i) photometry from the APASS (AAVSO Photometric All-Sky Survey) for over 50 million stars. UCAC4 also contains error estimates and various flags. All bright stars not observed with the astrograph have been added to UCAC4 from a set of Hipparcos and Tycho-2 stars. Thus UCAC4 should be complete from the brightest stars to about R=16, with the source of data indicated in flags. UCAC4 also provides a link to the original Hipparcos star number with additional data such as parallax found on a separate data file included in this release. The proper motions of bright stars are based on about 140 catalogs, including Hipparcos and Tycho, as well as all catalogs used for the Tycho-2 proper motion construction. Proper motions of faint stars are based on re-reductions of early epoch SPM data (-90 to about -20 deg Dec) and NPM (PMM scans of early epoch blue plates) for the remainder of the sky. These early epoch SPM data have also been combined with late epoch SPM data to arrive at proper motions partly independent from UCAC4 (Girard et al. 2011AJ....142...15G, Cat. I/320). The NPM data used in UCAC4 are not published. No Schmidt plate data are used in UCAC4. The unpublished plate measure data obtained by StarScan from the AGK2, the Hamburg Zone Astrograph, the USNO Black Birch Astrograph, and the Lick Astrograph have contributed to considerable improvement in proper motions for stars mainly in the 10 to 14 mag range (down to the UCAC limit for Lick data); however, these data do not cover all sky. Recources permitting, USNO plans to release the individual CCD observations (RA,Dec at epoch of each CCD observations) in the future. Please contact nz@usno.navy.mil if you are interested in obtaining this set of about 50 GB data. We will likely request that interested users provide an external disk drive for the data release.
656. UCAC3 Catalogue
ID:
ivo://CDS.VizieR/I/315
Title:
UCAC3 Catalogue
Short Name:
I/315
Date:
21 Oct 2021
Publisher:
CDS
Description:
UCAC3 is a compiled, all-sky star catalog covering mainly the 8 to 16 magnitude range in a single bandpass between V and R. Positional errors are about 15 to 20 mas for stars in the 10 to 14 mag range. It is supplemented by proper motions and SuperCosmos and 2MASS photometric data, as well as various flags. The proper motions of bright stars are based on about 140 catalogs, including Hipparcos and Tycho, as well as all catalogs used for the Tycho-2 proper motion construction. Proper motions of faint stars are based on a re-reduction of early epoch SPM data (-90 to -10 deg Dec) plus Schmidt plate data from the SuperCosmos project (down weighted due to systematic errors of order 100 mas). The proper motions of faint stars (R >= 13.5) therefore should be used with caution. The unpublished plate measure data from the AGK2, the Hamburg Zone Astrograph, the USNO Black Birch Astrograph, and the Lick Astrograph have considerably contributed to improve proper motions for stars mainly in the 10 to 14 mag range (down to the UCAC3 limit for Lick data); however, these data do not cover all sky. UCAC3 features a number of major differences with respect to UCAC2: - complete sky coverage - re-reduction of the pixel data with better modeling - double stars are resolved to the limit of the data - significantly improved photometry from CCD data - slightly deeper limiting magnitude with larger number of stars/area - reduced systematic errors of CCD observations - the addition of several new catalogs for improved proper motions - photometry in the B, R, and I bands from the SuperCosmos project - minor planet observations have been sorted out - identification of more high proper motion stars - match with 2MASS extended sources and LEDA galaxies Additional details will be published in the upcoming release paper (Zacharias et al. 2009) and in several technical papers describing details of the reduction procedures and results. For the latest updates see http://www.usno.navy.mil/usno/astrometry . Requests for the data DVD should be sent to ucac3@usno.navy.mil; technical questions can be addressed to nz@usno.navy.mil .
657. UCAC5 Catalogue
ID:
ivo://CDS.VizieR/I/340
Title:
UCAC5 Catalogue
Short Name:
I/340
Date:
21 Oct 2021
Publisher:
CDS
Description:
New astrometric reductions of the US Naval Observatory CCD Astrograph Catalog (UCAC) all-sky observations were performed from first principles using the TGAS stars in the 8 to 11 magnitude range as reference star catalog. Significant improvements in the astrometric solutions were obtained and the UCAC5 catalog of mean positions at a mean epoch near 2001 was generated. By combining UCAC5 with Gaia DR1 data new proper motions on the Gaia coordinate system for over 107 million stars were obtained with typical accuracies of 1 to 2mas/yr (R=11 to 15mag), and about 5mas/yr at 16th mag. Proper motions of most TGAS stars are improved over their Gaia data and the precision level of TGAS proper motions is extended to many millions more, fainter stars. External comparisons were made using stellar cluster fields and extragalactic sources. The TGAS data allow us to derive the limiting precision of the UCAC x, y data, which is significantly better than 1/100 pixel.
658. UCAC3 nocross
ID:
ivo://org.gavo.dc/ucac3/q/main
Title:
UCAC3 nocross
Short Name:
ucac3.main
Date:
27 Dec 2024 08:31:13
Publisher:
The GAVO DC team
Description:
The UCAC3 all-sky CCD astrograph catalogue, minus the fields from 2MASS and SuperCosmos and matching/object flags (which can be recovered with a local crossmatch).
659. Uccle AC Zone Data Reduced to ACRS
ID:
ivo://CDS.VizieR/I/231
Title:
Uccle AC Zone Data Reduced to ACRS
Short Name:
I/231
Date:
21 Oct 2021
Publisher:
CDS
Description:
The U.S. Naval Observatory is in the process of making new reductions of the Astrographic Catalogue (AC) using a modern reference system, the ACRS, which represents the system of the FK5. The data from the Uccle Zone, whose plates are centered between declinations +34 and +35 degrees (eq. 1900), have been analyzed for scale, rotation, tilt, coma, magnitude equation, radial distortion and distortions introduced by the use of reseaux in the Carte du Ciel program. The result is a positional catalog of over 117,000 stars on eq. J2000.0, epoch of observation. Additionally, all stars have been matched with the Tycho Input Catalog (revised); those numbers have been added for additional identification purposes.
660. Ultra-cool dwarfs candidates in Gaia DR2
ID:
ivo://CDS.VizieR/J/A+A/619/L8
Title:
Ultra-cool dwarfs candidates in Gaia DR2
Short Name:
J/A+A/619/L8
Date:
21 Oct 2021
Publisher:
CDS
Description:
The second Gaia data release (Gaia DR2) contains high-precision positions, parallaxes, and proper motions for 1.3 billion sources. The resulting Hertzsprung-Russel diagram reveals fine structures throughout the mass range. This paper aims to investigate the content of Gaia DR2 at the low-mass end and to characterize ultra-cool and brown dwarfs. We first retrieved the sample of spectroscopically confirmed ultra-cool and brown dwarfs in Gaia DR2.We used their locus in the precise Hertzsprung-Russel diagram to select new candidates and to investigate their properties. The number of spectroscopically confirmed objects recovered in Gaia DR2 corresponds to 61% and 74% of the expected number of objects with an estimated Gaia magnitude G_est_<=21.5 and 20.3, respectively. This fills much of the gap to Gaia DR1. Furthermore, Gaia DR2 contains ~13000>=M7 and 631 new L candidates. A tentative classification suggests that a few hundred of them are young or subdwarf candidates. Their distance distribution shows that the solar neighborhood census is still incomplete. Conclusions. Gaia DR2 offers a great wealth of information on low-mass objects. It provides a homogeneous and precise catalog of candidates that is worthwhile to be further characterized with spectroscopic observations.

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