Cosmological Implication of a New Measurement of the Submillimeter Background Radiation
Abstract
A new submillimeter measurement of the cosmic background radiation (CBR) by T. Matsumoto et al. (1988; Astrophys. J., 329, No. 2, in press) shows excess brightness between 1000 and 300 μm. The excess is large, corresponding to ~ 10 % of the undistorted blackbody radiation. A good fit to the new measurement is obtained from the assumption of nonrelativistic Compton scattering with the Zeldovich–Sunyaev parameter y = 0.028 and the temperature T0 = 2.75 K for the undistorted Planck spectrum. The predicted temperature for the Rayleigh-Jeans limit TRJ = 2.60 K, however, is significantly below the weighted average TA = 2.74±0.02 K of longer wavelength measurements. Relativistic Compton scattering models fit the data less well. A good fit to the entire data set is obtained by a model of the emission from dust heated by pregalactic starlight. For dust with an emissivity ɛ ∠λ–n, the dust temperature is Td = 3.7 (1+z) K for n = 2 and 4.4 (l+z) K for n = 1. The observed excess is consistent with thermal emission from dust with a relative density of Ωd ~ 10–4–10–5, if the dust was heated at a redshift of z ~ 10–40.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- December 1987
- DOI:
- Bibcode:
- 1987PASJ...39..941H
- Keywords:
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- Background Radiation;
- Black Body Radiation;
- Cosmic Rays;
- Cosmology;
- Radiant Flux Density;
- Submillimeter Waves;
- Astronomical Models;
- Compton Effect;
- Cosmic Dust;
- Astrophysics;
- Cosmic background radiation;
- Compton scattering;
- Dust emission