Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonthermal Hard X-Ray Emission from the Galactic Ridge   We investigate the origin of the nonthermal X-ray emission from the Galactic
ridge in the range 10-200 keV. We consider bremsstrahlung of subrelativistic
cosmic ray protons and electrons as production processes. From the solution of
the kinetic equations describing the processes of particle in-situ acceleration
and spatial propagation we derive parameters of the spectra for protons and
electrons. For in-situ acceleration the flux of accelerated particles consists
mainly of protons since the ratio of the accelerated protons to electrons is
large and the flux of nuclei with charges Z>1 is strongly suppressed. Our
analysis has shown that the proton bremsstrahlung model is free from the
previously discussed problems of the high gamma-ray flux at MeV or at hundreds
of MeV energy regions. However, the model with proton bremsstrahlung requires
specific restrictions on the proton spectrum.The real problem of the proton
bremsstrahlung model is the large pressure of the accelerated protons in the
disk. For the electron origin of the ridge flux we do not have the problems of
the gamma-ray line and continuous fluxes. On the other hand the electron
bremsstrahlung model requires more effective acceleration of background
particles.

22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex