EDP Sciences
Free access
Volume 428, Number 3, December IV 2004
Page(s) 717 - 721
Section Astrophysical processes
DOI http://dx.doi.org/10.1051/0004-6361:20047029

A&A 428, 717-721 (2004)
DOI: 10.1051/0004-6361:20047029

The Cerenkov iron K $\alpha$ line in Active Galactic Nuclei - calculation in the optically thin case

L. Chen1, D. B. Liu1, Y. D. Xu1, J. H. You1, A. F. Yuan2 and W. P. Chen3

1  Department of Physics, Shanghai Jiao-Tong University, Shanghai 200030, PR China
    e-mail: ajax@sjtu.edu.cn
2  Department of Physics, Tibet University, Tibet, PR China
3  Institute of Astronomy and Department of Physics, National Central University, Chung-Li 32054, Taiwan, PR China

(Received 8 January 2004 / Accepted 3 June 2004 )

In this paper we continue the research on the Cerenkov origin of the iron K $\alpha$ line in AGNs. We claim again that the newly recognized line emission mechanism, Cerenkov line-like radiation, could be significantly responsible for the observed iron K-lines of AGNs. We give a new model calculation of the luminosity of the iron K $\alpha$ line in the optically thin condition, which is an important extension of our previous calculation in the optically thick case. The new calculation is also comparable to the typical observed luminosity of iron K $\alpha$ line, thus confirming the effectiveness of the new mechanism. Besides, we analyze a possible negative influence of the hydrogen-dominated plasma upon the efficiency of Cerenkov line-like radiation in detail, which was ignored in our previous paper (You et al. 2003). We conclude that such a negative effect of the plasma oscillation is unimportant and can be neglected.

Key words: line: formation -- radiation mechanism: non-thermal -- X-rays: galaxies -- galaxies: Seyfert -- black hole physics

SIMBAD Objects

© ESO 2004