Continued decay in the cyclotron line energy in Hercules X-1

Staubert R, Klochkov D, Vybornov V, Wilms J, Harrison FA (2016)

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2016

Journal

Astronomy & Astrophysics EDP Sciences

Publisher: EDP Sciences

Book Volume: 590

Article Number: A91

DOI: 10.1051/0004-6361/201527955

Abstract

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.

Authors with CRIS profile

Jörn Wilms Professur für Astronomie und Astrophysik

Involved external institutions

Eberhard Karls Universität Tübingen DE Germany (DE) California Institute of Technology (Caltech) US United States (USA) (US)

How to cite

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://dx.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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