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Spectral evolution of active galactic nuclei: a unified description of the x-ray and gamma
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Leiter, D. Boldt, E. |
| Copyright Year | 1982 |
| Description | A model for spectral evolution is presented whereby active galactic nuclei (AGN) of the type observed individually emerge from an earlier stage at z approx = 4 in which they are the thermal X-ray sources responsible for most of the cosmic X-ray background (CXB). The conjecture is pursued that these precursor objects are initially supermassive Schwarzschild black holes with accretion disks radiating near the Eddington luminosity limit. It is noted that after approx. 10 to the 8th power years these central black holes are spun-up to a canonical Kerr equilibrium state (A/M = 0.998; Thorne 1974) and shown how they then can lead to spectral evolution involving non-thermal emission extending to gamma rays, at the expense of reduced thermal disk radiation. That major portion of the CXB remaining after the contribution of usual AGN are considered, while a superposition of AGN sources at z 1 can account for the gamma ray background. Extensive X-ray measurements carried out with the HEAO 1 and 2 missions as well as gamma ray and optical data are shown to compare favorably with principal features of this model. |
| File Size | 4388441 |
| Page Count | 68 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19820014263 |
| Archival Resource Key | ark:/13960/t91884b8c |
| Language | English |
| Publisher Date | 1982-02-01 |
| Access Restriction | Open |
| Subject Keyword | Space Radiation Quasars Galactic Evolution Luminosity Nonthermal Radiation Galactic Radiation Gamma Rays Seyfert Galaxies Active Galactic Nuclei X Rays Cosmology X Ray Spectra Background Radiation Black Holes Astronomy X Ray Sources Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
