Constant cyclotron line energy in Hercules X-1 — Joint Insight-HXMT and NuSTAR observations. (arXiv:1910.02393v1 [astro-ph.HE])

Constant cyclotron line energy in Hercules X-1 — Joint Insight-HXMT and NuSTAR observations. (arXiv:1910.02393v1 [astro-ph.HE])
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The long-term evolution of the centroid energy of the CRSF in Her X-1 is
still a mystery. We report a new measurement from a campaign between {sl
Insight}-HXMT and {sl NuSTAR} performed in February 2018. Generally, the two
satellites show well consistent results of timing and spectral properties. The
joint spectral analysis confirms that the previously observed long decay phase
has ended, and that the line energy instead keeps constant around 37.5 keV
after flux correction.

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