# Detection of an unidentified emission line in the stacked X-ray spectrum of galaxy clusters

@article{Bulbul2014DetectionOA,
title={Detection of an unidentified emission line in the stacked X-ray spectrum of galaxy clusters},
author={E. Bulbul and Maxim Markevitch and Adam R. Foster and Randall K. Smith and M. Loewenstein and S. W. Randall},
journal={The Astrophysical Journal},
year={2014},
volume={789},
pages={13}
}
• Published 10 February 2014
• Physics
• The Astrophysical Journal
We detect a weak unidentified emission line at E = (3.55-3.57) ± 0.03 keV in a stacked XMM-Newton spectrum of 73 galaxy clusters spanning a redshift range 0.01-0.35. When the full sample is divided into three subsamples (Perseus, Centaurus+Ophiuchus+Coma, and all others), the line is seen at >3σ statistical significance in all three independent MOS spectra and the PN "all others" spectrum. It is also detected in the Chandra spectra of the Perseus Cluster. However, it is very weak and located…
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