Modeling the Luminosity-dependent Pulse Profile and Emission Geometry of SMC X-2 during a Giant Outburst

Abstract One of the brightest X-ray pulsars in Small Magellanic Cloud is SMC X-2. During its most recent major outburst 2015, this transient pulsar displayed significant changes both accretion state and magnetosphere, particularly when it entered low-luminosity regime subcritical accretion. Polestar a pulse-profile modeling code that helps delineating geometry emission as source evolves past toward lower-luminosity states. Applying to XMM-Newton NuSTAR pulse profiles, we constrained likely inclination spin axis be i = 87° ± 4°. As luminosity declined, an increase pulsed fraction was detected from Swift observations, which suggests transition fan- pencil-beam during later stages outburst. Additionally, also performed analysis OGLE IV light curves, showed strong modulation optical profiles