Spectro-temporal study of atoll source GX 9+9 observed with AstroSat

Abstract

In this work, we performed a spectro-temporal investigation of the low-mass X-ray binary GX 9+9 using the Large Area X-ray Proportional Counter (LAXPC) and Soft X- ray Telescope (SXT) observation on board AstroSat. The source was detected in the soft state during the observation, which results in a disk dominating energy spectrum within the energy range of 0.7-25.0 keV. We carried out the analysis at different flux levels. In the temporal analysis, LAXPC data in all flux levels showed the presence of noise components, describing broad Lorentzian components. We modeled the energy-dependent temporal properties of the source in order to identify the radiative origin of the observed variability. This source is not a well-studied source; hence we attempt to estimate various source characteristics like inner-disk radius, flux, and inner-disk temperature.