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Title: Large-angular-scale anisotropy in the cosmic background radiation

Abstract

We report the results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3 K cosmic background radiation. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (0.89 cm wavelength) flown on board a U-2 aircraft to 20 km altitude. In 11 flights, between 1976 December and 1978 May, the radiometer measured differential intensity between pairs of directions distributed over most of the northern hemisphere. The measurements show clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fitted by a first order spherical harmonic of amplitude 3.6 +- 0.5 mK, corresponding to a velocity of 360 +- 50 km s/sup -1/ toward the direction 11.2 +- 0.5 hours of right ascension and 19/sup 0/ +- 8/sup 0/ declination. A simultaneous fit to a combined hypothesis of dipole and quadrupole angular distributions places a 1 mK limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 mK limit on uncorrelated fluctuations (sky-roughness) in the 3 K background on an angular scale of the antenna beam width, about 7/sup 0/.

Authors:
;
Publication Date:
Research Org.:
Space Sciences Laboratory and Lawrence Berkeley Laboratory, University of California, Berkeley
OSTI Identifier:
6335863
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophys. J.; (United States); Journal Volume: 244:2
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMIC RADIATION; ANISOTROPY; RADIOMETERS; CALIBRATION; ANGULAR DISTRIBUTION; BACKGROUND RADIATION; COSMOLOGY; DATA ACQUISITION; DATA ANALYSIS; GALAXY CLUSTERS; SPHERICAL HARMONICS; STATISTICS; UNIVERSE; DISTRIBUTION; IONIZING RADIATIONS; MATHEMATICS; MEASURING INSTRUMENTS; RADIATION DETECTORS; RADIATIONS; 640101* - Astrophysics & Cosmology- Cosmic Radiation; 640106 - Astrophysics & Cosmology- Cosmology

Citation Formats

Gorenstein, M.V., and Smoot, G.F. Large-angular-scale anisotropy in the cosmic background radiation. United States: N. p., 1981. Web. doi:10.1086/158714.
Gorenstein, M.V., & Smoot, G.F. Large-angular-scale anisotropy in the cosmic background radiation. United States. doi:10.1086/158714.
Gorenstein, M.V., and Smoot, G.F. Sun . "Large-angular-scale anisotropy in the cosmic background radiation". United States. doi:10.1086/158714.
@article{osti_6335863,
title = {Large-angular-scale anisotropy in the cosmic background radiation},
author = {Gorenstein, M.V. and Smoot, G.F.},
abstractNote = {We report the results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3 K cosmic background radiation. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (0.89 cm wavelength) flown on board a U-2 aircraft to 20 km altitude. In 11 flights, between 1976 December and 1978 May, the radiometer measured differential intensity between pairs of directions distributed over most of the northern hemisphere. The measurements show clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fitted by a first order spherical harmonic of amplitude 3.6 +- 0.5 mK, corresponding to a velocity of 360 +- 50 km s/sup -1/ toward the direction 11.2 +- 0.5 hours of right ascension and 19/sup 0/ +- 8/sup 0/ declination. A simultaneous fit to a combined hypothesis of dipole and quadrupole angular distributions places a 1 mK limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 mK limit on uncorrelated fluctuations (sky-roughness) in the 3 K background on an angular scale of the antenna beam width, about 7/sup 0/.},
doi = {10.1086/158714},
journal = {Astrophys. J.; (United States)},
number = ,
volume = 244:2,
place = {United States},
year = {Sun Mar 01 00:00:00 EST 1981},
month = {Sun Mar 01 00:00:00 EST 1981}
}