Staubert R, Klochkov D, Vybornov V, Wilms J, Harrison FA (2016)
Publication Status: Published
Publication Type: Journal article, Original article
Publication year: 2016
Publisher: EDP Sciences
Book Volume: 590
Article Number: A91
DOI: 10.1051/0004-6361/201527955
The centroid energy E of the cyclotron line in the spectrum of the binary X-ray pulsar Her X-1 has been found to decrease with time on a time scale of a few tens of years - surprisingly short in astrophysical terms. This was found for the pulse phase-averaged line centroid energy using observational data from various X-ray satellites over the time period 1996 to 2012, establishing a reduction of ∼4 keV. Here we report on the result of a new observation by NuSTAR performed in August 2015. The earlier results are confirmed and strengthened with respect to both the dependence of E on flux (it is still present after 2006) and the dependence on time: the long-term decay continued with the same rate, corresponding to a reduction of ∼5 keV in 20 yr.
APA:
Staubert, R., Klochkov, D., Vybornov, V., Wilms, J., & Harrison, F.A. (2016). Continued decay in the cyclotron line energy in Hercules X-1. Astronomy & Astrophysics, 590. https://doi.org/10.1051/0004-6361/201527955
MLA:
Staubert, R., et al. "Continued decay in the cyclotron line energy in Hercules X-1." Astronomy & Astrophysics 590 (2016).
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