Abstract Details

Name: Jithesh V
Affiliation: Inter-University Centre for Astronomy and Astrophysics
Conference ID: ASI2021_125
Title : Detection of Type-1 Bursts from NS LMXB 4U 1705-44 using Simultaneous AstroSat and NICER observations
Authors and Co-Authors : V. Jithesh (IUCAA, Pune), Diego Altamirano (University of Southampton), Ranjeev Misra (IUCAA, Pune), Bari Maqbool (IUCAA, Pune), Aru Beri (IISER, Mohali) and Mariano Méndez (Kapteyn Astronomical Institute)
Abstract Type : Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : The neutron star low mass X-ray binary, 4U 1705-44, was simultaneously observed with AstroSat and NICER observatories on 2020 September 18 with 20 and 14 ks exposure time, respectively. We found a steady source intensity during these observations, with three distinct Type-1 bursts detected. The first burst was detected only with the Large Area X-ray Proportional Counter (LAXPC) instrument onboard AstroSat. In contrast, the second burst was seen only with the X-ray Timing Instrument (XTI) of NICER and lasted for 28 seconds. The third burst was observed with both LAXPC and XTI detectors. In the second burst, we observed a double-peaked structure, where the peak intensity during these peaks differed by ~ 7%. The observed count rate of both the peaks was comparatively fainter in the soft (< 3keV) X-rays. The extracted power density spectra from these observations did not show the quasi-periodic oscillations, and we did not find the burst oscillations during the rising phase of the burst. We performed the broadband spectral analysis with the variable persistent flux method (fa-method) using SXT, LAXPC, and NICER spectra. Two blackbody components can describe the burst spectra along with the persistent emission model and the fa varied between the bursts. I will discuss the detailed broadband spectro-timing results in this talk.