ARCMINUTE SKY FLUCTUATIONS AT 1.25 MILLIMETERS

Observations of radio-quiet quasars made by the Swedish ESO Submiltimeter Telescope and the Institut de Radio Astronomie Millimetrique antenna at a frequency of 240 GHz have been used to infer upper limits on the 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% higher, 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 data, most of the primeval dust models can be ruled out and further constraints on the galaxy population contributing to the background can be determined.