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arXiv · 1406.5188

ALP Conversion and the Soft X-ray Excess in the Outskirts of the Coma Cluster

David Kraljic·Markus Rummel·Joseph P. Conlon
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Abstract

It was recently found that the soft X-ray excess in the center of the Coma cluster can be fitted by conversion of axion-like-particles (ALPs) of a cosmic axion background (CAB) to photons. We extend this analysis to the outskirts of Coma, including regions up to 5 Mpc from the center of the cluster. We extract the excess soft X-ray flux from ROSAT All-Sky Survey data and compare it to the expected flux from ALP to photon conversion of a CAB. The soft X-ray excess both in the center and the outskirts of Coma can be simultaneously fitted by ALP to photon conversion of a CAB. Given the uncertainties of the cluster magnetic field in the outskirts we constrain the parameter space of the CAB. In particular, an upper limit on the CAB mean energy and a range of allowed ALP-photon couplings are derived.

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David Kraljic, Markus Rummel, Joseph P. Conlon. 2014-06-19. ALP Conversion and the Soft X-ray Excess in the Outskirts of the Coma Cluster. https://doi.org/10.1088/1475-7516%2F2015%2F01%2F011

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