Presentation #116.50 in the session Stellar/Compact Objects.
The accreting pulsar 4U1907-09 is one of ~35 high-mass X-ray binaries with known high magnetic field strengths. A detected cyclotron resonance scattering feature at ~19 keV leads to a field strength of ~2E12 G. The system consists of a slowly-rotating (~440 s) X-ray pulsar accreting from the stellar wind of an O8/9 supergiant. The X-ray pulsar is in a close (~8.37 d) elliptical orbit (e ~ 0.28) around its donor.
We conducted an analysis of four High Energy Transmission Grating observations with the Chandra X-ray Observatory for a total of ~140 ks and one NuStar observations for 78 ks, at different orbital phases, to probe the variation of the absorbing column around the orbit. We measure line fluorescence at Fe K and possibly Si K and other lower Z elements to study dense clumps in the wind of the pulsar’s companion star. The details of NuSTAR detection used to determine the higher energy continuum beyond 10 keV will also be presented.