Paper: astro-ph/0512241

Date: Fri, 9 Dec 2005 06:09:19 GMT (23kb)

Title: Capture of a Red Giant by the Black Hole Sgr A* as a Possible Origin for
the TeV Gamma-Rays from the Galactic Center

Authors: Y. Lu, K.S. Cheng & Y.F. Huang

Comments: 15 pages, 1 figure, Accepted to ApJ
\\
Non-thermal TeV $\gamma$-ray emission within multi-pc scale has been observed
from the center region of our galaxy. We argue that these $\gamma$-rays are the
result of a transient activity of the massive black hole Sgr A$^*$ which
resides at the Galactic center. About thousands of years ago, the black hole
may have experienced an active phase by capturing a red giant star and forming
an accretion disk, temporarily behaving like an active galactic nuclear. A
powerful jet, which contains plenty of high speed protons, was launched during
the process. These runaway protons interact with the dense ambient medium,
producing TeV $\gamma$-ray emission through the $\pi^\circ$-decay process. We
show that the total energy deposited in this way is large enough to account for
observations. The diffusion length of protons is also consistent with the
observed size of the TeV source.

\\ ( http://arXiv.org/abs/astro-ph/0512241 , 23kb)