| タイトル | Spectral-luminosity evolution of active galactic nuclei and the cosmic X-ray background |
| 著者（英） | Boldt, Elihu; Leiter, Darryl |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 1991-01-01
1991 |
| 言語 | eng |
| 内容記述 | Black hole accretion disk dynamo processes are generally regarded as the central power source for AGN (Rees, 1984). If the precursor active galaxies for such AGN are formed at redshift z greater than about 4 and contain initial central seed black holes about 10 exp 6 solar masses, then the Eddington limited X-ray radiation emitted during their lifetime will undergo the phenomenon of 'spectral-luminosity evolution'. When accretion disks are first formed at the onset of galaxy formation, the accretion rate occurs at high values of luminosity/size compactness parameter L/R greater than 10 exp 30 erg/cm-sec. Such high values of L/R generate dynamic constraints which suppress nonthermal black hole accretion disk dynamo processes in favor of thermal processes. This causes the spectrum of X-radiation emitted by early AGN to be predominantly thermal. A superposition of such thermal, comptonized PAG sources can account for the residual cosmic X-ray background and can act as a source of X-ray heating of the intergalactic medium for z greater than about 4. |
| NASA分類 | ASTROPHYSICS |
| レポートNO | 93A23634 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/320553 |
|
