A 43-GHz Survey in the ELAIS N2 Area

TL;DR

This paper presents a 43-GHz survey of the ELAIS N2 region using the VLA, detecting a few sources and constraining source counts at 7 mJy, with results consistent with previous estimates but hinting at higher densities.

Contribution

First 43-GHz survey of ELAIS N2 region providing source counts constraints using maximum-likelihood analysis.

Findings

Detected one confirmed flat-spectrum QSO at z=2.2

Estimated source counts at 7 mJy are consistent with previous models

Results suggest possible higher surface densities at 43 GHz

Abstract

We describe a survey in the ELAIS N2 region with the VLA at 43.4 GHz, carried out with 1627 independent snapshot observations in D-configuration and covering about 0.5 square degrees. One certain source is detected, a previously-catalogued flat-spectrum QSO at z=2.2. A few (<5) other sources may be present at about the 3sigma level, as determined from positions of source-like deflections coinciding with blue stellar objects, or with sources from lower-frequency surveys. Independently we show how all the source-like detections identified in the data can be used with a maximum-likelihood technique to constrain the 43-GHz source counts at a level of ~7 mJy. Previous estimates of the counts at 43 GHz, based on lower-frequency counts and spectral measurements, are consistent with these constraints, although the present results are suggestive of somewhat higher surface densities at the 7 mJy level. They do not provide direct evidence of intrusion of a previously unknown source population, although the several candidate sources need examination before such a population can be ruled out.