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Precise Absolute Astrometry from the VLBA Imaging and Polarimetry Survey at 5 GHzWe present accurate positions for 857 sources derived from the astrometric analysis of 16 eleven-hour experiments from the Very Long Baseline Array imaging and polarimetry survey at 5 GHz (VIPS). Among the observed sources, positions of 430 objects were not previously determined at milliarcsecond-level accuracy. For 95% of the sources the uncertainty of their positions ranges from 0.3 to 0.9 mas, with a median value of 0.5 mas. This estimate of accuracy is substantiated by the comparison of positions of 386 sources that were previously observed in astrometric programs simultaneously at 2.3/8.6 GHz. Surprisingly, the ionosphere contribution to group delay was adequately modeled with the use of the total electron content maps derived from GPS observations and only marginally affected estimates of source coordinates.
Document ID
20120010096
Document Type
Reprint (Version printed in journal)
Authors
Petrov, L. (ADNET Systems, Inc. Potomac, MD, United States)
Taylor, G. B. (New Mexico Univ. Albuquerque, NM, United States)
Date Acquired
August 25, 2013
Publication Date
August 16, 2011
Publication Information
Publication: The Astronomical Journal
Volume: 142
Issue: 3
Subject Category
Astronomy
Report/Patent Number
GSFC.JA.00137.2012
Funding Number(s)
CONTRACT_GRANT: NNG06EB68C
Distribution Limits
Public
Copyright
Other