The 32nd Texas Symposium on Relativistic Astrophysics

High Resolution Spectra of the Galactic Binary Pulsar 4U 1907+09

11 Dec 2023, 17:11

12m

Hall # 10

Contributed talk in mini symposium Accretion Processes

Speaker

Dr Jun Yang (Harvard Smithsonian Center for Astrophysics)

Description

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 (CRSF) at ~19 keV leads
to a field strength of ~$\sim 2\times10^{12}$ 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 $\sim$ 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 observation 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 the NuSTAR
observation are used to determine the higher energy continuum beyond 10 keV.

Presentation materials

6-JunYang_Shanghai.pdf