Large scale anisotropy of the 3K cosmic background radiation at 24. 8, 31. 4 and 46. 0 GHz
The 3K cosmic background radiation (CBR), believed to be the signature of the initial singularity in ''big bang'' cosmologies, is a fundamental tool for understanding the structure of the early universe. Here a measurement of the spatial anisotropy of this radiation at a sensitivity of 6 parts in 10/sup 5/ is described. The observations were carried out in a balloon-borne package using three room temperature, correlation-type microwave radiometers, with 500 MHz bandwidths centered at 24.8, 31.4 and 46.0 GHz. The achieved system noise temperatures for the three receivers is 800K. Three flights between August 1978 and July 1980 cover the entire northern hemisphere sky, allowing for tests of both dipole and higher order anisotropies. A dipole effect is detected at the 4 mK level with heliocentric equatorial components (T/sub x/, T/sub y/, T/sub z/) = (-3.80, 0.63, -0.25) + (0.21, 0.20, 0.21)mK. If this is interpreted as a purely kinematic effect, the data imply a solar velocity of 410 + 20 km/sec towards ..cap alpha.. = 11.4 + 0.2 hours, delta = -3/sup 0/ + 3/sup 0/ relative to the CBR reference frame. The temperature spectral index of the dipole is determined to be -0.09 + 0.20, confirming that the radiation, in this frequency range, is that of a blackbody. No quadrupole anisotropy is present in the data, which place a 90% confidence upper limit of 0.4 mK on the quadrupole magnitude.
- Research Organization:
- Princeton Univ., NJ (USA)
- OSTI ID:
- 5008597
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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