Piero RANALLI
(Università di Bologna)
We are searching for X-ray emission from a sample of candidate
star-forming galaxies, selected on the basis of the optical colours of
the sources in the radio VLA-COSMOS catalogue (Smolcic et al.,
2008). The cross-correlation with the Chandra-COSMOS (C-COSMOS)
catalogue has allowed the detection of 33 sources. By analysing the
X-ray hardness ratios of the sources, the optical spectra, the
X-ray/radio and X-ray/infrared flux ratios, and comparing them with local-universe
analogues, we estimate the fraction of misclassifications in the
Smolcic et al. sample. The LogN-LogS of the C-COSMOS-detected galaxies
is presented and compared to other estimates from both
wide-and-shallow surveys and deep fields.
The possible evolution at high redshift of the star-forming galaxy
population without uncertainties due to absorption is investigated,
also using information directly derived from the C-COSMOS data for
sources just below the detection threshold. The method of stacking
X-ray images centred on the positions of sources not detected in the
X-rays is also used to gain further information about the average
properties of the fainter sources.