Abstract Details

Name: Gaurava K Jaisawal
Affiliation: Physical Research Laboratory, Ahmedabad
Conference ID: ASI2017_432
Title : First detection of cyclotron resonance scattering feature in high mass X-ray binary pulsar SMC X-2 with NuSTAR
Authors and Co-Authors : Sachindra Naik (PRL, Ahmedabad)
Abstract Type : Oral
Abstract Category : Stars,ISM and the Galaxy
Abstract : We have studied broadband spectral properties of the accretion powered X-ray pulsar SMC X-2 by using three simultaneous NuSTAR and Swift/XRT observations during its 2015 outburst. The pulsar was significantly bright (~5.5x10^38 ergs/s) during these observations, accreting above the Eddington luminosity of a canonical neutron star. Spin period of the pulsar was estimated to be 2.37 s. Pulse profiles were found to be strongly luminosity dependent. The 1-70 keV energy spectrum of the pulsar was well described with three different traditional continuum models. In addition to an iron line at ~6.4 keV, a model independent absorption like feature was detected at ~27 keV in the pulsar spectrum for the first time. We identified this feature as cyclotron absorption line of the pulsar. Corresponding magnetic field of the neutron star was estimated to be ~2.3x10^12 G. The cyclotron line energy showed a marginal negative dependence on the luminosity. The cyclotron line parameters were found to be variable with pulse phase and discussed in terms of viewing angle or the effect of the complicated structure in the magnetic field.