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191. Extension of ICRF for selected areas down to V=16
ID:
ivo://CDS.VizieR/J/A+A/409/361
Title:
Extension of ICRF for selected areas down to V=16
Short Name:
J/A+A/409/361
Date:
21 Oct 2021
Publisher:
CDS
Description:
A catalogue of accurate positions and proper motions for 678,828 objects is provided. Objects are within areas of special astronomical interest, containing extragalactic radio sources, mostly from ICRF (see Cat. <I/251>), and pre-main-sequence (PMS) stars in Southern star-forming regions (Chamaeleon, Lupus and Upper Scorpius-Ophiuchus). This work represents a major upgrade of that presented in Camargo et al., 2001, Cat. <J/A+A/375/308>, aiming at the extension of the ICRF at optical wavelengths in regions of special astronomical interest, using observations from the Bordeaux and Valinhos meridian circles. Along with the new fields, the main differences, when compared to the first release, are: a much larger sky coverage, the replacement of the AC2000 by its upgraded version AC2000.2 (<I/275>) as one of the first epoch astrometrical sources, inclusion of Tycho-2 (<I/259>) and 2MASS (2nd Incremental Data Release, See Cat <II/246>) photometry when available, and the correction for a magnitude equation on the Valinhos right ascension system as well. Positional external precisions, on both coordinates, range from 50-60mas (V<=13.5) to 70-140mas (13.5<V<=16.0). For the proper motions, precisions range from 3mas/year to about 15mas/year, depending on magnitude and declination. The strips scanned by the meridian circles are described in Table 1
192. Extension of ICRF for selected areas down to V=15
ID:
ivo://CDS.VizieR/J/A+A/375/308
Title:
Extension of ICRF for selected areas down to V=15
Short Name:
J/A+A/375/308
Date:
21 Oct 2021
Publisher:
CDS
Description:
A catalogue of accurate positions and proper motions for 41,721 objects is provided. Objects are within areas of special astronomical interest, containing extragalactic radio sources, mostly from ICRF (see Cat. I/251), and pre-main-sequence (PMS) stars in Southern star-forming regions (Chamaeleon, Lupus and Upper Scorpius-Ophiuchus). Positions and proper motions were derived by combining current epoch positions, obtained with the Valinhos CCD meridian circle (VMC, see 1999A&AS..134..173V), with first epoch catalogues, AC2000 (I/247) and USNO-A2.0 (I/252) mainly, as well as positions from plate measurements performed with the MAMA measuring machine (Guibert J., Charvin P. & Stoclet P., 1983, in Proceedings of the 78th Colloquium of the IAU), in Paris. On average, objects with V<=14.0 have positional precisions better than 50mas in both coordinates, and 100mas near the detection limit of the VMC (V~16,0). For proper motions, average precisions are better than 4mas/year, whatever the magnitude, when delta>=-17{deg}. To the south of this declination, a magnitude dependence is verified due to a particular feature of the USNO-A2.0's epochs, providing figures of 3mas/year when V<=12.0, where the participation of AC2000 is noted, and reaching 17mas/year at the detection limit. The catalogue data is grouped by area, following the same order and identification as given in table 2 of the paper; within each area, objects are sorted by right ascension. The respective record numbers for the beginning of each area are provided in a separate table.
193. Extragalactic radio sources optical positions
ID:
ivo://CDS.VizieR/J/A+AS/120/201
Title:
Extragalactic radio sources optical positions
Short Name:
J/A+AS/120/201
Date:
21 Oct 2021
Publisher:
CDS
Description:
Based on 28 individual catalogues, in which the positions of optical counterparts of extragalactic radio sources are listed, we compiled a combined catalogue by means of a weighted least squares adjustment. The catalogue is in the system of FK5/J2000.0. It consists of about five hundred sources, among which there are 56 primary sources with position uncertainties as 0.09". Comparisons show that the orientation differences between optical and radio frames are A1=-0.013"+/-0.012", A2=0.077"+/-0.012", A3=0.005"+/-0.009". Local relative deformations are not obvious within the precision of ground-based optical observations.
194. Extragalactic Reference Link Catalog (ERLcat)
ID:
ivo://CDS.VizieR/I/273A
Title:
Extragalactic Reference Link Catalog (ERLcat)
Short Name:
I/273A
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is an astrometric catalog, providing positions of 89,422 stars in 398 selected fields of extragalactic reference frame sources. The stars are mainly in the 11 to 14 magnitude range. The average positional accuracy is about 50 mas per coordinate at the epoch of observation, which is between 1976.2 and 1991.9. The observations are based on photographic plates, taken with 2 telescopes which are: - the Hamburg Zone astrograph (in the Northern Hemisphere) - the USNO Twin astrograph at Black Birch (New Zealand)
195. Far-UV photometry in Ori
ID:
ivo://CDS.VizieR/J/ApJS/89/259
Title:
Far-UV photometry in Ori
Short Name:
J/ApJS/89/259
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
196. FBS blue stellar objects DSS1/DSS2 astrometry
ID:
ivo://CDS.VizieR/J/A+A/426/367
Title:
FBS blue stellar objects DSS1/DSS2 astrometry
Short Name:
J/A+A/426/367
Date:
21 Oct 2021
Publisher:
CDS
Description:
Accurate measurements of the positions of 1103 First Byurakan Survey (FBS) blue stellar objects (the Second part of the FBS, <II/223>) have been carried out on the DSS1 and DSS2 (red and blue images). To establish the accuracy of the DSS1 and DSS2, measurements have been made for 153 AGN for which absolute VLBI coordinates have been published. The rms errors are: 0.45" for DSS1, 0.33" for DSS2 red, and 0.59" for DSS2 blue in each coordinate, the corresponding total positional errors being 0.64", 0.46", and 0.83", respectively. The highest accuracy (0.42") is obtained by weighted averaging of the DSS1 and DSS2 red positions. It is shown that by using all three DSS images accidental errors can be significantly reduced. The comparison of DSS2 and DSS1 images made it possible to reveal positional differences and proper motions for 78 objects (for 62 of these for the first time), including new high-probability candidate white dwarfs, and to find objects showing strong variability, i.e. high-probability candidate cataclysmic variables.
197. Field horizontal-branch stars in the Galaxy
ID:
ivo://CDS.VizieR/J/A+A/431/143
Title:
Field horizontal-branch stars in the Galaxy
Short Name:
J/A+A/431/143
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a sample of 8321 candidate Field Horizontal-Branch (FHB) stars selected by automatic spectral classification in the digital data base of the Hamburg/ESO objective-prism survey. The stars are distributed over 8225 square degrees of the southern sky, at |b|>~30{deg}. The average distance of the sample, assuming that they are all FHB stars, is 9.8kpc, and distances of up to ~30kpc are reached. Moderate-resolution spectroscopic follow-up observations and $UBV$ photometry of 125 test sample stars demonstrate that the contamination of the full candidate sample with main-sequence A-type stars is <16%, while it would be up to 50% in a flux-limited sample at high galactic latitudes. Hence more than ~6800 of our FHB candidates are expected to be genuine FHB stars. The candidates are being used as distance probes for high-velocity clouds and for studies of the structure and kinematics of the Galactic halo.
198. Fifth Fundamental Catalogue (FK5) - Extension
ID:
ivo://CDS.VizieR/I/175
Title:
Fifth Fundamental Catalogue (FK5) - Extension
Short Name:
I/175
Date:
21 Oct 2021
Publisher:
CDS
Description:
The FK5 Extension provides improved mean positions and proper motions for the 3117 new fundamental stars. The machine version of the catalog contains the positions and proper motions of the Extension stars for the epochs and equinoxes J2000.0 and B1950.0, the mean epochs of individual observed right ascensions and declinations used to determine the final positions, the mean errors of the final positions and proper motions for the reported epochs, and ancillary data such as magnitudes, spectral types, parallaxes, and radial velocities. Cross identifications to the numbering systems of the AGK3R, SRS, HD, DM, and GC catalogs are also included.
199. Fifth Fundamental Catalogue (FK5) Part I
ID:
ivo://CDS.VizieR/I/149A
Title:
Fifth Fundamental Catalogue (FK5) Part I
Short Name:
I/149A
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Basic Fifth Fundamental Catalogue (FK5) Part I provides improved mean positions and proper motions for the 1535 classical fundamental stars that had been included in the FK3 and FK4 catalogs. The machine version of the catalog contains the positions and proper motions of the Basic FK5 stars for the epochs and equinoxes J2000.0 and B1950.0, the mean epochs of individual observed right ascensions and declinations used to determine the final positions, the mean errors of the final positions and proper motions for the reported epochs, and ancillary data such as magnitudes, spectral types, parallaxes, radial velocities, and cross identifications to other catalog designations.
200. Fifth VLBA calibrator survey: VCS5
ID:
ivo://CDS.VizieR/J/AJ/133/1236
Title:
Fifth VLBA calibrator survey: VCS5
Short Name:
J/AJ/133/1236
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents the fifth part of the Very Long Baseline Array (VLBA) Calibrator Survey (VCS), containing 569 sources not observed previously with very long baseline interferometry in geodetic or absolute astrometry programs. This campaign has two goals: (1) to observe additional sources that, together with previous survey results, form a complete sample, and (2) to find new strong sources suitable as phase calibrators. This VCS extension was based on three 24-hr VLBA observing sessions in 2005. It detected almost all extragalactic flat-spectrum sources with correlated flux density greater than 200mJy at 8.6GHz above declination -30{deg} that were not observed previously. Source positions with milliarcsecond accuracy were derived from astrometric analysis of ionosphere-free combinations of group delays determined from the 2.3 and 8.6GHz frequency bands. The VCS5 catalog of source positions, plots of correlated flux density versus projected baseline length, contour plots, and FITS files of naturally weighted CLEAN images, as well as calibrated visibility function files, are available on the World Wide Web at http://vlbi.gsfc.nasa.gov/vcs5

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