Large-scale distribution of galactic X-ray sources

The global distribution of galactic X-ray sources (GXRSs) listed in the fourth Uhuru catalog (number-intensity, longitude, and latitude distributions) is reasonably well reproduced in the framework of three basic assumptions: (i) the creation rate of GXRSs, N/sub X/, varies with position within the galactic disk as a function of the ambient gas density p/sub g/ according to the relation N/sub X/=kp/sub g//sup n/, where k and n are free parameters; (ii) the luminosity function of GXRSs can be parametrized by dN/dLproportionalL/sup -alpha/; and (iii) X-ray sources are runaway systems.The best fit of the number-intensity distribution as well as of the longitude distribution is obtained with the two parameters n=1.35 and ..cap alpha..=1.1.The scale height of GXRSs is predicted to vary versus galactocentric distance. The latitude distribution of GXRSs is well reproduced when their azimuthal migration is taken into account, provided the mean velocity normal to the galactic plane is of the order of 100 km s/sup -/1.