The Fifth VLBA Calibrator Survey: VCS5

This paper presents the fifth extension to the Very Long Baseline Array (VLBA) Calibrator Survey (VCS), containing 569 sources not observed previously with very long baseline interferometry. 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 degrees. 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 projected baseline length, contour plots and fits files of naturally weighted CLEAN images, as well as calibrated visibility function files are available on the Web at http://vlbi.gsfc.nasa.gov/vcs5