Four-year COBE DMR cosmic microwave background observations: Mapsand basic results

Journal Article · Wed Jan 10 00:00:00 EST 1996 · Astrophysical Journal

DOI:https://doi.org/10.1086/310075· OSTI ID:894241

Bennett, C L; Banday, A J; Gorski, K M; Hinshaw, G; Jackson, P; Keegstra, P; Kogut, A; Smoot, G F; Wilkinson, D T; Wright, E L

In this Letter we present a summary of the spatial properties of the cosmic microwave background radiation based on the full 4 yr of COBE Differential Microwave Radiometer (DMR) observations, with additional details in a set of companion Letters. The anisotropy is consistent with a scale-invariant power-law model and Gaussian statistics. With full use of the multifrequency 4 yr DMR data, including our estimate of the effects of Galactic emission, we find a power-law spectral index of n = 1.2 +/- 0.3 and a quadrupole normalization Q(rms-PS) = 15.31(-2.8)(+3.8) mu K. For n = 1 the best-fit normalization is Q(rms-PS/n=1) = 18 +/- 1.6 mu K. These values are consistent with both our previous 1 yr and 2 yr results. The results include use of the l = 2 quadrupole term; exclusion of this term gives consistent results, but with larger uncertainties. The final DMR 4 yr sky maps, presented in this Letter, portray an accurate overall visual impression of the anisotropy since the signal-to-noise ratio is similar to 2 per 10 degrees sky map patch. The improved signal-to-noise ratio of the 4 yr maps also allows for improvements in Galactic modeling and limits on non-Gaussian statistics.

• Research Organization: COLLABORATION - NASA
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 894241
• Report Number(s): LBNL--61840
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Vol. 464; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANISOTROPY
QUADRUPOLES
RADIATIONS
RADIOMETERS
RELICT RADIATION
SIGNAL-TO-NOISE RATIO
SIMULATION
SKY
STATISTICS