Foregrounds Removal and CMB Fluctuations in a Multiband Anisotropy Experiment: ARGO 1993

We present the results of a diffuse radiation survey carried out at millimeter and submillimeter wavelengths in the Aries and Taurus sky regions. A balloon-borne telescope with 0.dg86 FWHM resolution and four millimeter-wave bands scanned 147 independent sky directions. From the multiband observations we were able to separate two independent components: thermal emission from cirrus dust and cosmic microwave background (CMB) temperature fluctuations. A statistically significant detection of anisotropies is found in the data of the CMB channel: Delta Tsky = (24 +/- 7) mu K rms (95% CL plus 10% calibration error). Assuming uncorrelated Gaussian temperature fluctuations we find a band averaged estimate of the CMB anisotropy power spectrum Cl = (20 +/- 9) mu K2 at l ~= 110. The data are consistent with anisotropies in a "standard" Omega b = 0.05, n = 1 model normalized to the rms anisotropy detected by COBE Differential Microwave Radiometers.