Broadband spectroscopy using two Suzaku observation of the HMXB GX 301-2

TL;DR

This study analyzes two Suzaku observations of the high-mass X-ray binary GX 301-2, revealing variable absorption, fluorescence lines, and a cyclotron resonance scattering feature, providing insights into the neutron star's magnetic field and geometry.

Contribution

It presents the first detailed analysis of CRSF and magnetic dipole geometry in GX 301-2 using two Suzaku observations at different orbital phases.

Findings

Detected variations in column density indicating clumpy wind accretion.

Identified multiple fluorescence emission lines in the spectra.

Constrained the neutron star's magnetic dipole geometry and inclination.

Abstract

We present the analysis of two Suzaku observations of GX 301-2 at two orbital phases after the periastron passage. Variations in the column density of the line-of-sight absorber are observed, consistent with accretion from a clumpy wind. In addition to a CRSF, multiple fluorescence emission lines were detected in both observations. The variations in the pulse profiles and the CRSF throughout the pulse phase have a signature of a magnetic dipole field. Using a simple dipole model we calculated the expected magnetic field values for different pulse phases and were able to extract a set of geometrical angles, loosely constraining the dipole geometry in the neutron star. From the variation of the CRSF width and energy, we found a geometrical solution for the dipole, making the inclination consistent with previously published values.