AstroSat view of the neutron star low mass X-ray binary GX 5-1

The spectral and timing study of the bright NS-LMXB GX 5-1 using AstroSat observations. During the observation, the source traces out the complete HB and NB of the Z-track in the HID. Understanding the spectral and temporal evolution of the source along the 'Z' track can probe the accretion process in the vicinity of a neutron star. Spectral analysis was performed in the 0.7-20 keV energy range for different segments in the HID using a multi-temperature disc black body with an average temperature, kTin∼0.46 and a thermal Comptonization model. It is found that the optical depth of the corona drops from ∼6.68 in HB to ∼2.74 in NB. The Timing analysis using the LAXPC instrument indicates the presence of quasi-periodic oscillations in HB, NB, and the hard apex of the Z-track. The observed QPO frequencies are similar to the characteristic frequencies of horizontal branch and normal branch oscillations. The HBO frequency increase from ∼12-46 Hz towards the hard apex. The timing studies conducted in soft and hard band indicate the association of HBO and NBO origin with the non-thermal component. Further research could explore the implications of this relationship for understanding the dynamics of accretion onto neutron stars.