Comprehensive spectro-temporal studies of GX 17

We performed a comprehensive spectro-temporal study of the Z-type neutron star low-mass X-ray binary GX 17 + 2 using long term data from the AstroSat /Soft X-ray Telescope (SXT) and Large Area X-ray Proportional Counter (LAXPC). The hardness-intensity diagrams (HIDs) of the source revealed a positive correlation between the hardness and intensity, characteristic of soft spectral state. Additionally, the LAXPC-20 HID showed the presence of secular shifts in both hardness and intensity. Time-averaged spectral modelling in the 0.7 -30.0 key energy range indicated that the spectra could be well fitted with the model combination: constant x edge x edge x tbabs x thcomp x bbodyrad. This analysis yielded a blackbody radius (R-bb) of 59 km, photon index (Gamma) of similar to 2.84 and electron temperature (kT(e)) of similar to 4.84 key. Time-averaged temporal analysis revealed normal branch oscillations (NBOs) at similar to 7 Hz in Observations 1 and 3, flaring branch oscillation (FBO) at 15 Hz in Observation 2, and horizontal branch oscillation (HBO) at 36 Hz in Observation 5. Flux resolved spectro-temporal analysis indicated that the source remained in the soft spectral state throughout all observations. A positive correlation was observed between kT(bb), F-bb and F-bol, whereas an anti-correlation was noted between kT(e) and F-bol. The constant frequency of NBOs with an increase in F-bol suggests that their origin lies in a region strongly influenced by the corona, as explained by the radiation-hydrodynamic model. The origin of FBOs may be attributed to the damped radiation-hydrodynamic mode of radial flow, while the origin of HBOs is supported by the beat-frequency model.