|COOKIES: By using this website you agree that we can place Google Analytics Cookies on your device for performance monitoring.|
The Cluster Soft Excess, Dark Radiation and a 0.1-1 keV Cosmic Axion Background
If you have a question about this talk, please contact mustafa.a.amin.
Since 1996 soft excess emission above thermal bremsstrahlung from the intracluster medium has been observed from galaxy clusters in extreme ultraviolet and soft X-ray frequencies. We review proposed astrophysical explanations, and the difficulties they face in the light of cluster magnetic field measurements and null observations of clusters in gamma rays. String theory moduli that decay at t ~ 10-6 s generally have non-zero branching ratios to axion-like particles. These freestream to the present day and currently constitute a dark radiation Cosmic Axion Background at 0.1 – 1 keV energies. These axions can convert into photons in cluster magnetic fields, and allowed particle physics parameters can easily generate the required excess luminosity of approximately 1043 erg s-1. For the case of Coma, we use a detailed model of the Coma magnetic field to calculate the axion conversion probabilities and to study the resulting excess morphology.
This talk is part of the Cosmology lunch series.
This talk is included in these lists:
Note that ex-directory lists are not shown.
Other listsKing's Review Salons Cambridge Radiology Forum Humanitarian Centre
Other talksEurope’s Energy Security in the Wake of TTIP and Brexit:-A Legal Perspective Unorthodox Interactions at Work Advanced Techniques for Privacy-Preserving Linking of Multiple Large Databases Health Economics @ Cambridge seminar: Title TBC The history of Gallery 3 and its Parthenon frieze Common Law and the origins of shareholder protection