IOP Publishing Ltd.;United Kingdom: The American Astronomical Society
摘要:
摘要： ABSTRACT From the rate of hydrogen ionization and the gamma-ray flux, we derived the spectrum of relativistic and subrelativistic cosmic rays (CRs) nearby and inside the molecular cloud Sgr B2 near the Galactic Center. We studied two cases of CR propagation in molecular clouds: free propagation and scattering of particles by magnetic fluctuations excited by the neutral gas turbulence. We showed that in the latter case CR propagation inside the cloud can be described as diffusion with a coefficient of cm2 s−1. For the case of hydrogen ionization by subrelativistic protons, we showed that their spectrum outside the cloud is quite hard with a spectral index of . The energy density of subrelativistic protons ( eV cm−3) is one order of magnitude higher than that of relativistic CRs. These protons generate the 6.4 keV emission from Sgr B2, which was about 30% of the flux observed by Suzaku in 2013. Future observations for the period after 2013 may discover the background flux generated by subrelativistic CRs in Sgr B2. Alternatively, hydrogen ionization of the molecular gas in Sgr B2 may be caused by high energy electrons. We showed that the spectrum of electron bremsstrahlung is harder than the observed continuum from Sgr B2, and in principle, this X-ray component provided by electrons could be seen from the INTEGRAL data as a stationary high energy excess above the observed spectrum . 其他題名： APJ 其他題名： Astrophys. J 出版者： United Kingdom: The American Astronomical Society 出版日期： 2015-08-10 出處： The Astrophysical journal, 2015-08, Vol.809 (1), p.48-12 資源來源： Institute of Physics Journals 版權： 2015. The American Astronomical Society. All rights reserved. 識別號： ISSN: 0004-637X 識別號： ISSN: 1538-4357 識別號： EISSN: 1538-4357 識別號： DOI: 10.1088/0004-637X/809/1/48
