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Statistics and topology of the COBE differential microwave radiometer first-year sky mapsWe use statistical and topological quantities to test the Cosmic Background Explorer (COBE) Differential Microwave Radiometer (DMR) first-year sky maps against the hypothesis that the observed temperature fluctuations reflect Gaussian initial density perturbations with random phases. Recent papers discuss specific quantities as discriminators between Gaussian and non-Gaussian behavior, but the treatment of instrumental noise on the data is largely ignored. The presence of noise in the data biases many statistical quantities in a manner dependent on both the noise properties and the unknown cosmic microwave background temperature field. Appropriate weighting schemes can minimize this effect, but it cannot be completely eliminated. Analytic expressions are presented for these biases, and Monte Carlo simulations are used to assess the best strategy for determining cosmologically interesting information from noisy data. The genus is a robust discriminator that can be used to estimate the power-law quadrupole-normalized amplitude, Q(sub rms-PS), independently of the two-point correlation function. The genus of the DMR data is consistent with Gaussian initial fluctuations with Q(sub rms-PS) = (15.7 +/- 2.2) - (6.6 +/- 0.3)(n - 1) micro-K, where n is the power-law index. Fitting the rms temperature variations at various smoothing angles gives Q(sub rms-PS) = 13.2 +/- 2.5 micro-K and n = 1.7(sup (+0.3) sub (-0.6)). While consistent with Gaussian fluctuations, the first year data are only sufficient to rule out strongly non-Gaussian distributions of fluctuations.
Document ID
19950040483
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Smoot, G. F.
(Univ. of California, Berkeley, CA United States)
Tenorio, L.
(Univ. of California, Berkeley, CA United States)
Banday, A. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kogut, A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Wright, E. L.
(Univ. of California, Los Angeles, CA United States)
Hinshaw, G.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Bennett, C. L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
December 10, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 437
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A72082
Funding Number(s)
CONTRACT_GRANT: NAGW-2448
CONTRACT_GRANT: NSF AST-90-20506
Distribution Limits
Public
Copyright
Other

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