Measurement of anisotropy in the cosmic background radiation on a large angular scale at 33 GHz

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6214142

Gorenstein, M V

This thesis presents the results of a measurement of anisotropy in the 3/sup 0/K cosmic background radiation on a large-angular-scale. 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 20-km altitude. In eleven flights, between December 1976 and May 1978, the radiometer measured differential intensity between pairs of directions distributed over most of the northern celestial hemisphere with an rms sensitivity of +-46m/sup 0/K/..sqrt..Hz. The measurements show clear evidence of anisotropy that is readily interpreted as due to the motion of the earth relative to the sources of the radiation; the anisotropy is well fit by a cosine distribution of amplitude 3.61 +- 0.54 milli-degrees Kelvin (m/sup 0/K), one part in 800 of 3/sup 0/K, implying a velocity of 361 +- 54 km/sec toward the direction 11.23 +- 0.46 hours right ascension, and 19.0 +- 7.5/sup 0/ declination. A simultaneous fit to a combined hypothesis of dipole (cosTHETA) and quadrupole (cos/sup 2/THETA) angular distributions places a 1 m/sup 0/K limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 m/sup 0/K limit on uncorrelated fluctuations (sky-roughness) in the 3/sup 0/K background on an angular scale of the antenna beam width, about 7/sup 0/. This thesis describes the equipment development through three engineering flights and the data acquisition in eleven additional flights. The astrophysical results are then presented from the statistical analysis of the reduced data.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6214142
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIRCRAFT
AMPLITUDES
ANISOTROPY
BACKGROUND RADIATION
COSMIC RADIATION
DISTRIBUTION
FREQUENCY RANGE
GHZ RANGE
GHZ RANGE 01-100
IONIZING RADIATIONS
MEASURING INSTRUMENTS
RADIATION DETECTORS
RADIATIONS
RADIOMETERS
ULTRALOW TEMPERATURE