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

TL;DR

This study uses multi-frequency observations from the 9C survey at 15 GHz to empirically estimate source counts at higher frequencies relevant to Planck and ALMA, aiding in understanding extragalactic source populations.

Contribution

It provides the first empirical estimates of source counts at multiple high radio frequencies based on 15 GHz data, comparing them with existing models and data.

Findings

Estimated source counts at 22, 30, 43, and 70 GHz.

Predicted source population at 90 GHz for ALMA calibration.

Comparison with theoretical models and existing data.

Abstract

We have used multi-frequency 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 GHz, 30 GHz, 43 GHz 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 ALMA frequency of 90 GHz, with a view to assessing the possible population of point sources available for the phase calibration of that instrument.