Mainz 2017 – scientific programme
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A: Fachverband Atomphysik
A 16: XUV/X-ray spectroscopy III
A 16.6: Talk
Tuesday, March 7, 2017, 16:00–16:15, N 2
The 3.5 keV X-ray line: a dark matter decay line or an unknown plasma line? — •Stepan Dobrodey1, Chintan Shah1, Sven Bernitt1,2, René Steinbrügge1, Liyi Gu3, Jelle Kaastra3, and José Ramón Crespo López-Urrutia1 — 1Max-Planck-Institut für Kernphysik, Heidelberg, Germany — 2Friedrich-Schiller-Universität Jena, Jena, Germany — 3SRON Netherlands Institute for Space Research, Utrecht, Netherlands
Speculations about a possible dark matter origin of an observed unidentified X-ray line feature at 3.5 keV from galaxy clusters have sparked an incredible interest in the scientific community and given rise to a tide of publications attempting to explain the possible cause for this line [1,2]. Motivated by this, we have measured the K-shell X-ray spectra of highly ionized bare sulfur ions following charge exchange with gaseous molecules in an electron beam ion trap, as a source of or contributor to this X-ray line. We produced S16+ and S15+ ions and let them capture electrons in collision with those molecules with the electron beam turned off while recording X-ray spectra. We observed a charge-exchange-induced X-ray feature at the Lyman series limit (3.47 ± 0.06 keV). The inferred X-ray energy is in full agreement with the reported astrophysical observations and supports the proposed novel scenario by Gu [2,3].
E. Bulbul et al., ApJ, 13, 789 (2014)
L. Gu et al., A&A, L11, 584 (2015)
C. Shah et al., ApJ, in press (2016)