The VLBA Galactic Plane Survey -- VGaPS
  This paper presents accurate absolute positions from a 24 GHz Very Long
Baseline Array (VLBA) search for compact extragalactic sources in an area where
the density of known calibrators with precise coordinates is low. The goals
were to identify additional sources suitable for use as phase calibrators for
galactic sources, determine their precise positions, and produce radio images.
In order to achieve these goals, we developed a new software package, PIMA, for
determining group delays from wide-band data with much lower detection limit.
With the use of PIMA we have detected 327 sources out of 487 targets observed
in three 24 hour VLBA experiments. Among the 327 detected objects, 176 are
within 10 degrees of the Galactic plane. This VGaPS catalogue of source
positions, plots of correlated flux density versus projected baseline length,
contour plots, as well as weighted CLEAN images and calibrated visibility data
in FITS format, are available on the Web at http://astrogeo.org/vgaps.
Approximately one half of objects from the 24 GHz catalogue were observed at
dual band 8.6 GHz and 2.3 GHz experiments. Position differences at 24 GHz
versus 8.6/2.3 GHz for all but two objects on average are strictly within
reported uncertainties. We found that for two objects with complex structure
positions at different frequencies correspond to different components of a
source.
