Some estimates of the source counts at Planck Surveyor frequencies, using the 9C survey at 15 GHz

Abstract

We have used multifrequency follow-up observations of a sample of extragalactic sources from the 9C survey at 15 GHz to make deductions about the expected source population at higher radio frequencies, such as those in the lower frequency bands of the Planck Surveyor satellite. In particular, we have made empirical estimates of the source counts at 22, 30, 43 and 70 GHz and compared these with both known data and current theoretical predictions. We have also made an estimate of the count at the Atacama Large Millimeter Array (ALMA) frequency of 90 GHz, with a view to assessing the possible population of point sources available for the phase calibration of that instrument.