Early science with Korean VLBI network: the QCAL-1 43GHz calibrator
  survey
  This paper presents the catalog of correlated flux densities in three ranges
of baseline projection lengths of 637 sources from a 43 GHz (Q-band) survey
observed with the Korean VLBI Network. Of them, 623 sources have not been
observed before at Q-band with VLBI. The goal of this work in the early science
phase of the new VLBI array is twofold: to evaluate the performance of the new
instrument that operates in a frequency range of 22-129 GHz and to build a list
of objects that can be used as targets and as calibrators. We have observed the
list of 799 target sources with declinations down to -40 degrees. Among them,
724 were observed before with VLBI at 22 GHz and had correlated flux densities
greater than 200 mJy. The overall detection rate is 78%. The detection limit,
defined as the minimum flux density for a source to be detected with 90%
probability in a single observation, was in a range of 115-180 mJy depending on
declination. However, some sources as weak as 70 mJy have been detected. Of 623
detected sources, 33 objects are detected for the first time in VLBI mode. We
determined their coordinates with the median formal uncertainty 20 mas. The
results of this work set the basis for future efforts to build the complete
flux-limited sample of extragalactic sources at frequencies 22 GHz and higher
at 3/4 of the celestial sphere.
