Michael Wayne Wise

Far-infrared emission from the intracluster medium

IRAS images of 56 clusters of galaxies are examined for evidence of diffuse, extended FIR emission at 60 and 100 microns. Of these 56 clusters, five show evidence of FIR excess, but at low levels of significance. For A496 and MKW 1, this excess is attributable to the presence of a strong point source at or near the position of the central cD galaxy. In A2344, the observed 100-micron excess is the result of the presence of a foreground cirrus concentration which coincides with the cluster. Examination of the sample as a whole indicates that clusters exhibit excess FIR emission at the 2-sigma level for apertures 4 and 10 arcmin in diameter. FIR luminosities range from about 1-0 exp 9 solar luminosities for the smallest aperture to about 10 exp 14 solar luminosities for the entire cluster.