Magnetic flares and the observed optical depth in seyfert galaxies
May, 19976 pages
Published in:
- Astrophys.J.Lett. 490 (1997) L13
e-Print:
- astro-ph/9705255 [astro-ph]
DOI:
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Abstract: (arXiv)
We here consider the pressure equilibrium during an intense magnetic flare above the surface of a cold accretion disk. Under the assumption that the heating source for the plasma trapped within the flaring region is an influx of energy transported inwards with a group velocity close to , e.g., by magnetohydrodynamic waves, this pressure equilibrium can constrain the Thomson optical depth to be of order unity. We suggest that this may be the reason why in Seyfert Galaxies. We also consider whether current data can distinguish between the spectrum produced by a single X-ray emitting region with and that formed by many different flares spanning a range of . We find that the current observations do not yet have the required energy resolution to permit such a differentiation. Thus, it is possible that the entire X-ray/-ray spectrum of Seyfert Galaxies is produced by many independent magnetic flares with an optical depth .References(2)
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