Latest COBE results

Abstract

The latest results on the spectrum and anisotropy of the microwave background from the COsmic Background Explorer (COBE) are discussed. The RMS deviation of the spectrum from a 2.728 .004 K [95% CL] Planck function is less than 50 parts per million of the peak intensity. Energy added to the CMBR by hot electrons (y and μ distortions) is less than 60 parts per million [95% CL] of the total CMBR energy for all times later than 1 year after the Big Bang. The anisotropy of the CMBR is consistent with a power law power spectrum of primordial density perturbations with P(k) σ kn, and the spectral index n = 1.2 .3 (1σ), consistent with the n≈ 1 predicted by inflation. The amplitude of power spectrum gives an expected RMS quadrupole of 〈QRMS2〉0.5 = 18 μK if n is forced to be 1.