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

摘要

We have refined the analysis of the data from the FIRAS (Far-InfraRed Absolute Spectrophotometer) on board the COBE (COsmic Background Explorer). The FIRAS measures the difference between the cosmic microwave background and a precise blackbody spectrum. We find new, tighter upper limits on general deviations from a blackbody spectrum. The rms deviations are less than 50 parts per million of the peak of the cosmic microwave background radiation. For the Comptonization and chemical potential, we find |y| < 15 x 10~(-6) and |μ| < 9 x 10~(-5) (95% confidence level [CL]). There are also refinements in the absolute temperature, 2.728 ± 0.004 K (95% CL), the dipole dlrection, (l, b) = (264°.14 ± 0.30, 48°.26 ± 0.30) (95% CL), and the amplitude, 3.372 ± 0.014 mK (95% CL). All of these results agree with our previous publications.