ISO deep far-infrared survey in the "Lockman Hole" II. Power spectrum analysis: evidence of a stro

Two 44’ ×44’ fields in the Lockman hole have been surveyed at 95 and 175μm with ISOPHOT. The raw data were reduced by PIA up to AAP products and then the responsivity drift was corrected by the median filter technique. IRAF DAOPHOT was used to extract point sources from the maps. Simulations generating artificial objects show the effect of source confusion is significant in the flux range below 200 mJy. The differential and cumulative source number density vs flux relations were derived after correction for the confusion effect. The number densities have excess over the models by Guiderdoni et al. by a factor of 10–50. The slopes of the number densities are similar at the both wavelengths, implying far-infrared sources are at low redshift. Comparisons with radio and X-ray sources indicate most of far-infared sources are star-forming galaxies.