VLBA Calibrator Survey 5 (VCS5)


Summary

Here the fifth extension to the Very Long Baseline Array (VLBA) Calibrator Survey, containing 569 new sources not previously observed with very long baseline interferometry (VLBI) is presented. The main goal of this campaign is to observe additional sources supplementing previous survey results to construct a statistically complete sample of extragalactic flat-spectrum radio sources. This VCS extension, based on three 24 hour VLBA observing sessions, detected almost all remaining extragalactic flat-spectrum sources with correlated flux density greater than 200 mJy at 8.6 GHz above declination -30°. It also increases the number of known sources suitable as phase calibrators. Source positions with milliarcsecond accuracy were derived from astrometric analysis of ionosphere free combinations of group delays determined at 2.3 and 8.6 GHz frequency bands. The VCS5 catalogue of source positions, plots of correlated flux density versus the length of projected baseline, contour plots and fits files of naturally weighted CLEAN images as well as calibrated visibility function files are available at this page.

Publication:
Y.Y. Kovalev, L. Petrov, E. Fomalont, D. Gordon "The Fourth VLBA Calibrator Survey - VCS5", Astronomical Journal, 2007, Vol. 133, pp. 1236-1242.    Preprint: astro-ph/0607524    Full text   (PS + gzip, 134Kb )    PDF-file.

Observations

There were three observing sessions, each 24 hour long: VCS5a, VCS5b and VCS5c:

VCS5a was observed from 2005.07.08_19:41 till 2005.07.09_19:30
VCS5b was observed from 2005.07.09_20:33 till 2005.07.10_20:34
VCS5c was observed from 2007.07.20_23:13 till 2005.07.21_23:10

Date Experiment Session URL for downloading Size (bytes)
2005.07.08 vcs5a $05JUL08XV ftp://cddis.gsfc.nasa.gov/vlbi/raw/fits/2005_07_08_vcs5a_fits.tar.bz2 10,402,147,383
2005.07.09 vcs5b $05JUL09XV ftp://cddis.gsfc.nasa.gov/vlbi/raw/fits/2005_07_09_vcs5b_fits.tar.bz2 10,820,635,915
2005.07.20 vcs5c $05JUL20XV ftp://cddis.gsfc.nasa.gov/vlbi/raw/fits/2005_07_20_vcs5c_fits.tar.bz2 10,292,185,078

Results

  1. VCS5 catalogue in HTML form. The catalogue contains positions os 590 targeted sources, their uncertainties, estimates of the total VLBA flux density, the VLBA flux density of unresolved components, naturally weighted CLEAN images in postscript and in fits format at X and S-band; plots of the correlated flux density as a function of the length of the baseline projection to the source plane; fits files with calibrated uv data.
  2. VCS5 catalogue in ASCII format. The catalogue contains source positions, their uncertainties, total VLBA flux density, the VLBA flux density of unresolved components.
  3. Catalogue in HTML form of 70 sources used as tropospheric calibrators. The catalogue contains source positions, their uncertainties, estimates of the total VLBA flux density, the VLBA flux density of unresolved components, naturally weighted CLEAN images in postscript and in fits format at X and S-band; plots of the correlated flux density as a function of the length of the baseline projection to the source plane; fits files with calibrated uv data.
  4. Catalogue in ASCII format of 70 sources used as tropospheric calibrators.
  5. All images and uv data in one tar.bz2 file (422Mb). Refer to the readme file for the file name convention in this archive.

569 new sources and 21 previusly observed sources of 675 targets have been detected. Among them, 433 are suitable as calibrators (more than 8 X/S good observations, semi-major error ellipse is less than 25 nrad (5 mas)).


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Last update: 28-JUL-2006 15:18:13
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