Speaker
Vladimir Dogiel
(P.N.Lebedev Institute of Physics)
Description
We investigate the origin of the diffuse 6.4~keV line emission and the source of H$_2$ ionization in the diffuse molecular gas of the Galactic center (GC) region. We showed that Fe atoms are most likely ionized by X-ray photons emitted by Sgr~A$^\ast$ during a previous period of flaring activity of the supermassive black hole. The H$_2$ molecules of the diffuse gas can not be ionized by photons from Sgr A$^\ast$, because soft photons are strongly absorbed in the interstellar gas around the central black hole. The molecular hydrogen in the GC region is most likely ionized by low-energy cosmic rays, probably protons rather than electrons, whose contribution into the diffuse 6.4 keV line emission is negligible.
Author
Vladimir Dogiel
(P.N.Lebedev Institute of Physics)