Jm. Wrobel et al., Phase calibration sources in the northern sky at galactic latitudes vertical bar b vertical bar < 2(.)over-circle5, ASTRONOM J, 122(3), 2001, pp. 1669-1672
The Jodrell Bank-VLA Astrometric Survey (JVAS) of flat-spectrum sources yie
lded a catalog of 2118 compact radio sources in the northern sky. Those sou
rces are being used as phase calibrators for many synthesis arrays. JVAS su
ffers from a zone of avoidance because Galactic confusion prevented selecti
on of flat-spectrum sources at \b \ < 2.<degrees>5. This confusion problem
was overcome by selecting variable sources from the GB6 Catalog in the JVAS
zone of avoidance. A subset of these sources were observed at 8.5 GHz with
the NRAO VLA in the JVAS style, leading to 29 compact radio sources in the
zone of avoidance whose positions have been measured to an rms accuracy of
about 10 mas or less. This extension of the JVAS lists to lower Galactic l
atitudes (1) improves the prospects for VLBA phase-referencing of Galactic
targets and (2) strengthens the lists' usefulness for studies of the Galact
ic interstellar medium.