Name: Sabyasachi Pal
Affiliation: Midnapore City College
Conference ID : ASI2022_540
Title : Broad-band study of the X-ray pulsar EXO 2030+375 during the type-II outburst in 2021 using NICER and NuSTAR
Authors : Sabyasachi Pal and Manoj Mandal
Abstract Type: Oral
Abstract Category : Stars, ISM and Galaxy
Abstract : The X-ray pulsar EXO 2030+375 went through a type-II outburst in July 2021 and the X-ray flux reached 0.6 Crab as observed by Swift/BAT (15-50 keV), which is highest after the 2006 giant outburst. We have studied the evolution of the timing and spectral properties of the source using different NuSTAR and NICER observations throughout the outburst. The spin period was found to be 41.204 s during the outburst using NuSTAR observation. The pulse profile showed a broad single peak feature from NuSTAR (3-79 keV) observation. The variation of pulsed fraction, beaming pattern, and emission geometry is studied for different mass accretion rates using different NICER observations. The Cyclotron Resonant Scattering Feature (CRSF) for the source is doubtful. We have investigated the CRSF feature using the NuSTAR spectrum. The broad-band energy spectrum was fitted using a composite model with two components, a black body emission, and a cut-off power law. An iron emission line was also found near 6.4 keV. We have used the torque-luminosity model to look for the correlation between the pulse frequency derivative and luminosity and to estimate the magnetic dipole moment and the surface magnetic field of the pulsar.