摘要
We describe a survey in the ELAIS N2 region with the Very Large Array at 43.4 GHz, carried out with 1627 independent snapshot observations in D-configuration and covering about 0.5 deg(2). One certain source is detected, a previously catalogued flat-spectrum quasi-stellar object at z = 2.2. A few (<5) other sources may be present at about the 3 sigma detection 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 similar to 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.
- 出版日期2010-10-21