Victor Doroshenko

astrophysicist@IAAT

Dec 04, 2020

X-ray reprocessing in accreting pulsar GX 301-2 observed with Insight-HXMT

Another nice work based on Insight-HXMT data. The last one for Long Ji while in Tuebingen :( Congratulations on new position, Long!

In the paper investigate the absorption and emission features in observations of GX 301-2 detected with Insight-HXMT/LE in 2017-2019. At different orbital phases, we found prominent Fe K\(_\alpha\), K\(_\beta\) and Ni K\(_\alpha\) lines, as well as Compton shoulders and Fe K-shell absorption edges. These features are due to the X-ray reprocessing caused by the interaction between the radiation from the source and surrounding accretion material. According to the ratio of iron lines K\(_\alpha\) and K\(_\beta\), we infer the accretion material is in a low ionisation state. We find an orbital-dependent local absorption column density, which has a large value and strong variability around the periastron. We explain its variability as a result of inhomogeneities of the accretion environment and/or instabilities of accretion processes. In addition, the variable local column density is correlated with the equivalent width of the iron K\(_\alpha\) lines throughout the orbit, which suggests that the accretion material near the neutron star is spherically distributed.