Name: Varun Varun
Affiliation: Aryabhatta Research Institute of Observational Sciences, Nainital
Conference ID : ASI2022_434
Title : AstroSat detection of a mHz quasi-periodic oscillation and cyclotron line in IGR J19294+1816 during the 2019 outburst
Authors : Gayathri Raman, Varun, Biswajit Paul, Dipankar Bhattacharya
Abstract Type: Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : We present results from timing and spectral analysis of the high-mass X-ray binary X-ray pulsar IGR J19294+1816 observed using AstroSat during its recent Type-I outburst in 2019 October. AstroSat observations sampled the outburst at the decline phase right after the outburst peak. We carried out a timing analysis on the light curves obtained using the Large Area X-ray Proportional Counter (LAXPC) instrument onboard AstroSat and measured a spin period of 12.485 065 ± 0.000 015 s. The peak in the power-density spectrum (PDS) corresponding to the spin period of 12.48 s also shows a broadened base. We also detected a quasi-periodic oscillation (QPO) feature at 0.032 ± 0.002 Hz with an RMS fractional amplitude of ∼18 percent in the PDS. We further carried out a joint spectral analysis using both the Soft X-ray Telescope and the LAXPC instruments and detected a cyclotron resonant scattering feature (CRSF) at 42.7 ± 0.9 keV and a Fe emission line at 6.4 ± 0.1 keV. IGR J19294+1816, being an intermediate spin pulsar, has exhibited a plethora of spectral and timing features during its most recent 2019 outburst, adding it to the list of transients that exhibit both a QPO as well as a CRSF.