ARCMINUTE SKY FLUCTUATIONS AT 1.25 MILLIMETERS

Observations of radio-quiet quasars made by the Swedish ESO Submiltime ter Telescope and the Institut de Radio Astronomie Millimetrique anten na at a frequency of 240 GHz have been used to infer upper limits on t he sky fluctuations at angular scales of 30'', 70'', and 140''. It is found that DELTAT/T < 1.4 x 10(-4) at 30'', DELTAT/T < 2.4 x 10(-4) at 70'', and DELTAT/T < 1.9 X 10(-4) at 140'' (95% confidence level) for uncorrelated patches of sky. The two former limits are 70% and 10% hi gher, respectively, if detections of radio-quiet objects are included in the analysis. These limits can be used in the context of (1) models predicting far-infrared cosmic backgrounds originating from primeval dust and (2) models of dusty galaxy evolution. On the basis of these d ata, most of the primeval dust models can be ruled out and further con straints on the galaxy population contributing to the background can b e determined.