SIGNAL-TO-NOISE EIGENMODE ANALYSIS OF THE 2-YEAR COBE MAPS

To test best a theory of cosmic microwave background fluctuations, anisotropy maps [here the two-year Cosmic Background Explorer differential microwave radiometer (DMR) 53, 90, 31 GHz a and b and the Far-Infrared Survey (FIRS) 170 GHz maps] are expanded in a complete basis of linear combinations of pixel amplitudes-statistically independent for both the noise and the signal. Bayesian analysis of a 2-parameter inflation-inspired theory shows the overall band-power and spectral tilt index νΔT+1 for all maps agree within 1σ, {(1.1±0.1)×10-5}2 and 1.27±0.33 (compatible with inflation values, ∼0.8-1.2); and S/N filtering of the DMR maps reveals the same large-scale structural features. © 1995 The American Physical Society.