J/AJ/129/1163 Third VLBA calibrator survey: VCS3 (Petrov+, 2005)
The third VLBA calibrator survey: VCS3.
Petrov L., Kovalev Y.Y., Fomalont E., Gordon D.
<Astron. J., 129, 1163-1170 (2005)>
=2005AJ....129.1163P 2005AJ....129.1163P
ADC_Keywords: Radio sources ; Surveys ; Positional data
Keywords: astrometry - catalogs - quasars: general - radio continuum: general -
reference systems - techniques: interferometric
Abstract:
We present the third extension to the Very Long Baseline Array (VLBA)
Calibrator Survey, containing 360 new sources not previously observed
with Very Long Baseline Interferometry (VLBI). The survey, based on
three 24 hour VLBA observing sessions, fills the areas on the sky
above declination -45° where the calibrator density is less than one
source within a 4° radius disk at any given direction. The positions
were derived from astrometric analysis of the group delays determined
at 2.3 and 8.6GHz frequency bands using the CALC/SOLVE software
package. The VCS3 catalog of source positions, plots of correlated
flux density versus length of projected baseline, and contour plots
and FITS files of naturally weighted CLEAN images, as well as
calibrated visibility function files, are available electronically
from the Goddard Geodetic VLBI Group.
Description:
The VCS3 observations were carried out in three 24hr observing
sessions with the VLBA on 2004 April 30, May 8, and May 27. The
observations used the VLBA dual-frequency geodetic mode, observing
simultaneously at 2.3 and 8.6GHz. Each band was separated into four
intermediate-frequency channels, with bandwidth 8MHz which spanned
140MHz at 2.3GHz and 490MHz at 8.6GHz, in order to provide precise
measurements of group delays for astrometric processing.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 111 360 The VCS3 catalog
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See also:
VIII/60 : Interferometer phase calibration sources (Patnaik+ 1998)
J/ApJS/141/13 : VLBA calibrator Survey - VCS1 catalog (Beasley+, 2002)
J/AJ/126/2562 : Second VLBA calibrator survey: VCS2 (Fomalont+, 2003)
http://gemini.gsfc.nasa.gov/vcs3/ : VLBA Calibrator Survey 3 (VCS3)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1 A1 --- Cat Source category (1)
3- 10 A8 --- IVS The IVS (Internation VLBI Service for Geodesy
and Astrometry) B1950 source name (HHMM+DDd)
12- 21 A10 --- VCS3 Third VLBA Calibrator Survey J2000 source name
23- 24 I2 h RAh Hour of Right ascension (J2000.0)
26- 27 I2 min RAm Minute of Right ascension (J2000.0)
29- 37 F9.6 s RAs Second of Right ascension (J2000.0)
39 A1 --- DE- Sign of the Declination (J2000.0)
40- 41 I2 deg DEd Degree of Declination (J2000.0)
43- 44 I2 arcmin DEm Arcminute of Declination (J2000.0)
46- 53 F8.5 arcsec DEs Arcsecond of Declination (J2000.0)
55- 60 F6.2 mas e_RAs Inflated error in Right Ascension
62- 67 F6.2 mas e_DEs Inflated error in Declination
69- 74 F6.3 --- Corr Correlation between RA and Dec
76- 78 I3 --- Nobs Number of observations used
80 A1 --- l_T8.4GHz [←] flag for T8.4 (2)
81- 84 F4.2 Jy T8.4GHz ? Total VLBA 8.4GHz (X-band) flux density
86 A1 --- l_U8.4GHz [←] flag for U8.4 (2)
87- 90 F4.2 Jy U8.4GHz ? Unresolved VLBA 8.4GHz (X-band) flux density
92 A1 --- l_T2.3GHz [←] flag for T2.3 (2)
93- 96 F4.2 Jy T2.3GHz ? Total VLBA 2.3GHz (S-band) flux density
98 A1 --- l_U2.3GHz [←] flag for U2.3 (2)
99-102 F4.2 Jy U2.3GHz ? Unresolved VLBA 2.3GHz (S-band) flux density
104-106 A3 --- Band Used bands (3)
108-111 A4 --- --- [VCS3] Catalog name
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Note (1): Source category:
C = calibrator source;
- = not a calibrator source.
Note (2): Flag on the correlated flux density:
- = no data in the following column present.
< = upper limit of the flux density is presented in the following column.
Note (3): Band code, defined as follows:
X/S = ionosphere-free linear combination of X and S wide-band group delays;
X = X-band only group delay;
S = S-band only group delay.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 01-Aug-2005