2013/05/31 by Joseph P. Conlon, M. C. David Marsh
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Axion #Background radiation #COSMIC cancer database #Cosmic ray #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Nuclear physics #Optics #Photon #Physics #Radiation #astro-ph.CO #astro-ph.HE #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevlett.111.151301
published as Phys. Rev. Lett. 111, 151301 (2013) · 4 pages, 2 figures. References and figures updated; v3. matches published version
openalex publication_date 2013/10/11 · arxiv created 2014/05/23 · arxiv updated 2014/05/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Primordial decays of string theory moduli at z~10(12) naturally generate a dark radiation cosmic axion background with 0.1-1 keV energies. This cosmic axion background can be detected through axion-photon conversion in astrophysical magnetic fields to give quasithermal excesses in the extreme ultraviolet and soft x-ray bands. Substantial and observable luminosities may be generated even for axion-photon couplings <<10(-11) GeV(-1). We propose that axion-photon conversion may explain the observed excess emission of soft x rays from galaxy clusters, and may also contribute to the diffuse unresolved cosmic x-ray background. We list a number of correlated predictions of the scenario.