Gamma-Ray Spectral Characteristics of Thermal and Non-Thermal Emission from Three Black Holes
| dc.creator | Ling, James C. | |
| dc.creator | Wheaton, William A. | |
| dc.date | 2004-09-13 | |
| dc.date | 2004-10-05 | |
| dc.date.accessioned | 2026-07-07T02:14:35Z | |
| dc.date.available | 2026-07-07T02:14:35Z | |
| dc.description | Cygnus X-1 and the gamma-ray transients GROJ0422+32 and GROJ1719-24 displayed similar spectral properties when they underwent transitions between the high and low gamma-ray (30 keV to few MeV) intensity states. When these sources were in the high gamma-ray intensity state (gamma-2, for Cygnus X-1), their spectra featured two components: a Comptonized shape below 200-300 keV with a soft power-law tail (photon index >3) that extended to ~1 MeV or beyond. When the sources were in the low-intensity state (gamma-0, for Cygnus X-1), the Comptonized spectral shape below 200 keV typically vanished and the entire spectrum from 30 keV to ~1 MeV can be characterized by a single power law with a relatively harder photon index ~2-2.7. Consequently the high- and low-intensity gamma-ray spectra intersect, generally in the ~400 keV - 1 MeV range, in contrast to the spectral pivoting seen previously at lower (~10 keV) energies. The presence of the power-law component in both the high- and low-intensity gamma-ray spectra strongly suggests that the non-thermal process is likely to be at work in both the high and the low-intensity situations. We have suggested a possible scenario (Ling & Wheaton, 2003), by combining the ADAF model of Esin et al. (1998) with a separate jet region that produces the non-thermal gamma-ray emission, and which explains the state transitions. Such a scenario will be discussed in the context of the observational evidence, summarized above, from the database produced by EBOP, JPL's BATSE earth occultation analysis system. | |
| dc.description | 6 pages, 3 figures, accepted for publication in Proceedings of 2004 Microquasar Conference, Beijing, China, Chinese Journal of Astronomy and Astrophysics, minor corrections per referee | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0409307 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0409307 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/8171 | |
| dc.subject | Astrophysics | |
| dc.title | Gamma-Ray Spectral Characteristics of Thermal and Non-Thermal Emission from Three Black Holes | |
| dc.type | text |