Abstract Details

Name: Neal Thomas
Affiliation: CHRIST (Deemed to be University)
Conference ID: ASI2020_156
Title : AstroSat’s view of the neutron star low mass X-ray binary GX 340+0
Authors and Co-Authors : Neal Titus Thomas, S. B. Gudennavar, S. G. Bubbly and R. Misra
Abstract Type : Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : GX 340+0, a neutron star low mass X-ray binary (NS-LMXB), was discovered as a galactic X-ray source in 1967. Based on the pattern it traced on its X-ray hardness intensity diagram (HID) and its correlated spectro-temporal properties, the source was classified as a Z-type NS-LMXB. Further studies resulted in the sub classification of it as a Cygnus-like Z source. These sources exhibit different states, which correspond to characteristic spectral and temporal variability. The exact physical mechanism that drives the different classes of NS-LMXB still remains an open question. We have carried out in-depth spectral and temporal variability studies of GX 340+0 using ~ 40 ks data from the SXT and LAXPC instruments on-board AstroSat. The HID showed that the source was undergoing a transition from the horizontal branch to the normal branch during the observations. We observe quasi-periodic oscillations (QPOs) whose frequencies agree well with the frequency of horizontal branch oscillations (HBOs) and normal branch oscillations (NBOs). These are thought to be caused due to the perturbations in the accretion disk and act as probes into changes in the accretion geometry of the source. Further, the dynamic temporal analysis showed that the HBO is dominant in lower energy, whereas the NBO is dominant in the higher energy. This indicates that these QPOs originate from different sites of the system. We have also correlated these temporal variations with the spectral parameters of the source through flux resolved spectroscopy. These results will be presented.