THE COSMIC MICROWAVE BACKGROUND SPECTRUM FROM THE FULL COBE FIRAS DATA SET

We have refined the analysis of the data from the FIRAS (Far-InfraRed Absolute Spectrophotometer) on board the COBE (COsmic Background Explo rer). The FIRAS measures the difference between the cosmic microwave b ackground and a precise blackbody spectrum. We find new, tighter upper limits on general deviations from a blackbody spectrum. The rms devia tions are less than 50 parts per million of the peak of the cosmic mic rowave background radiation. For the Comptonization and chemical poten tial we find \y\ < 15 x 10(-6) and \mu\ < 9 x 10(-5) (95% confidence l evel [CL]). There are also refinements in the absolute temperature, 2. 728 +/- 0.004 K (95% CL), the dipole direction, (l, b) = (264.14 degre es +/- 0.30, 48.26 degrees +/- 0.30) (95% CL), and the amplitude, 3.37 2 +/- 0.014 mK (95% CL). All of these results agree with our previous publications.