view Abstract Citations (60) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS X-Rays from the Galactic Center, External Galaxies, and the Intergalactic Medium. Gould, R. J. ; Burbidge, G. R. Abstract The various mechanisms which have been proposed to explain the cosmic X-rays observed by Giacconi, Gursky, Paolini, and Rossi are reviewed. It is shown that the electron-proton bremsstrahlung from a spectrum of energetic non-relativistic electrons can account for the observed X-rays from the direction of the galactic center, provided the total energy density of these electrons is greater than about one- hundredth of the energy density of the thermal particles in the center. If there is a flux of high energy particles (electrons or protons) in the galactic center, certain monochromatic X-rays, from K-series transitions following a K-shell ionization, should also be emitted at an observable rate. Thus detailed observations in the X-ray region should give information about both the particle fluxes in the central region of the galaxy and the relative abundances of elements which give K-series X-rays. It is also shown that the osbserved intensity of the isotropic background X-rays is incompatible with the "hot universe" model of the steady-state cosmological theory, and that the intergalactic medium must have a temperature less than 10' degrees, if its density is as large as the value 2 X 10-29 gm/cm3 predicted by the steady-state theory. However, the observed intensity of these background X-rays is comparable to that expected from all external galaxies, on the assumption that all galaxies emit X-rays from their center at the same rate as our own Galaxy. Publication: The Astrophysical Journal Pub Date: November 1963 DOI: 10.1086/147698 Bibcode: 1963ApJ...138..969G full text sources ADS |