"Particle acceleration in the interstellar medium and origin of the hard X-ray emission from the Galactic disk"
Prof. V.A. Dogiel (I.E.Tamm Theoretical Physics Division, P.N.Lebedev Physical Institute)
Abstract:
We
analyze processes for the hard X-ray emission from the Galactic disk,
whose origin has remained enigmatic for many years. Up to now no model has
been able to explain the physical origin of this emission. Even the most
plausible mechanism of bremsstrahlung radiation requires an energy output
in emitting particles higher than the luminosity provided by known
Galactic sources. We show that this energy enigma can be resolved if the
emission comes directly from regions of particle acceleration. In this
case a broad quasi-thermal transition region of particle excess is formed
between the thermal and nonthermal energy regions. Then the necessary
energy output for production of quasi-thermal electrons emitting 10 keV
X-rays can definitely be supplied by supernovae or other known Galactic
sources of energy.