Primeval galaxies: Predicted luminosities |
| |
| Authors: | Michele Kaufman |
| |
| Institution: | (1) Astronomy Dept., University of Texas, Austin, Tex., USA;(2) Present address: Physics Dept., University of Notre Dame, Notre Dame, Ind., USA |
| |
| Abstract: | Absorption by gas and dust in circumstellar Hii regions within primeval galaxies could seriously depress the far-ultraviolet continuum radiation emitted by primeval galaxies. This effect might account for the failure of Partridge (1974) and Davis and Wilkinson (1974) to detect the redshifted radiation from primeval galaxies at optical and near-infrared wavelengths. A primeval galaxy becomes very bright only during the final stages of contraction. Provided that dust can form by the time the primeval galaxy reaches peak luminosity, a significant fraction of the stellar far-ultraviolet radiation is converted into far-infrared. Thus an appropriate spectral region to search for the redshifted integrated background from primeval galaxies lies between 350  , where the 2.7 K microwave background radiation becomes important, and 150 , where other extragalactic discrete sources, such as nearby galactic nuclei, may contribute. The expected IR flux is calculated with Kaufman's (1975) model for the star formation rate in the contracting galaxy. Letz
p be the redshift andT
g the grain temperature when the primeval galaxy becomes very bright. Unlessz
p 10 orT
g is fairly high, the intensity of the far-infrared radiation from primeval galaxies would be dominated by the high frequency tail of the 2.7 K microwave background. On the other hand, if dust is unimportant, we determine the spectral energy distribution of a primeval galaxy emitted in the range 912 Å to 2050 Å; we find that the luminosities are not very sensitive to the dependence of effective temperatures on metal abundance. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
