Large-angular-scale anisotropy in the cosmic background radiation

Journal Article · Sun Mar 01 00:00:00 EST 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158714· OSTI ID:6335863

Gorenstein, M V; Smoot, G F

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/.

• Research Organization: Space Sciences Laboratory and Lawrence Berkeley Laboratory, University of California, Berkeley
• OSTI ID: 6335863
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 244:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
640106 -- Astrophysics & Cosmology-- Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANGULAR DISTRIBUTION
ANISOTROPY
BACKGROUND RADIATION
CALIBRATION
COSMIC RADIATION
COSMOLOGY
DATA ACQUISITION
DATA ANALYSIS
DISTRIBUTION
GALAXY CLUSTERS
IONIZING RADIATIONS
MATHEMATICS
MEASURING INSTRUMENTS
RADIATION DETECTORS
RADIATIONS
RADIOMETERS
SPHERICAL HARMONICS
STATISTICS
UNIVERSE