X-ray nova flares

In order to find out the physical nature of galactic X-ray sources, data on variability of 24 sources during 1964–1971 have been investigated. The fluxes of 9 sources are found to be increasing to the maximum value (for several months) and then slowly decreasing (for }3 yr). These 9 sources have been related by us to the class of X-ray novae. The X-ray nova synthetic light curve has been drawn from data on the fluxes of 9 discovered novae. Assumptions have been made on the physical nature of the X-ray novae. Between the flares the X-ray novae may be weak X-ray sources with luminosity about 10³⁴ erg s^?1. During the flares the luminosity increases to about 10³⁸ erg s^?1. The number of X-ray sources in the Galaxy is about 10⁴–10⁵, the average distance between them about 0.5 kpc. The object of the optical identification may be a dwarf star of no earlier spectral class than F.     

Second catalogue of X-ray sources

A catalogue of X-ray sources containing 677 objects known as of 1979 September has been compiled. X-ray data collected by means of rockets, balloons, and satellites during 1964–1979 are listed. Optical and radio counterparts are suggested. The existence of the weak X-ray sources population in the Galaxy is indicated. The number of X-ray sources of each type in the Galaxy is estimated.Astrophysics and Space Science review paper.