Infrared Cosmic Background Radiation
Observation of the cosmic background radiation in the infrared region is reviewed.
The redshifted light from stars of the first generation forms diffuse cosmic background radiation in the near-infrared region. Measurement of the sky fluctuation at 2.2μm gives a very low upper limit. The rocket observation of the near-infrared diffuse emission reveals isotropic emission which is possibly ascribed to an extra-galactic origin. The observed brightness and fluctuation are not consistent with the standard scenario of the primeval galaxies.
In the far-infrared region, integrated light of dust emission of the distant galaxies forms another cosmic background radiation. IRAS and the Nagoya-Berkeley rocket experiment found a clear correlation between HI column density and far-infrared sky brightness, however, there remains an uncorrelated isotropic emission component. If we ascribe this emission to be extragalactic origin, a fairly big evolution effect is required.
In the submillimeter region, the Nagoya-Berkeley rocket experiment has shown that the submillimeter cosmic background is much brighter than expected from the 2.74K blackbody spectrum. The excess energy corresponds to about 10% of the 2.74K blackbody, which requires the vast energy generation in the early universe.
KeywordsCosmic Background Radiation Column Density Dust Emission Interstellar Dust Interplanetary Dust
Unable to display preview. Download preview PDF.
- Akiba, M., Matsumoto, T., and Murakami, H. 1989, submitted to Aatr.Ap.Google Scholar
- Boughn, S.P. and Kuhn, J.R., Ap. J., 309, 33.Google Scholar
- Hayakawa, S., Matsumoto, T., and Nishimura, T. 1970, Space Res., 10, 248.Google Scholar
- Lange, A.E., Richards, P.L., Hayakawa, S., Matsumoto, T., Matsuo, H., Murakami, H., and Sato, S. 1989, submitted to Ap.J.Google Scholar
- Rowan-Robinson, M and Carr, B 1988, Post-Recombination Universe, ed. N. Kaiser and A.N. Lasenby, p.125.Google Scholar