Axion searches with Fermi and IACTs

Abstract

Axion Like Particles (ALPs), postulated to solve the strong-CP problem, are predicted to couple with photons in the presence of magnetic fields, which may lead to a significant change in the observed spectra of gamma-ray sources such as AGNs. Here we simultaneously consider in the same framework both the photon/axion mixing that takes place in the gamma-ray source and that one expected to occur in the intergalactic magnetic fields. We show that photon/axion mixing could explain recent puzzles regarding the observed spectra of distant gamma-ray sources as well as the recently published lower limit to the EBL intensity. We finally summarize the different signatures expected and discuss the best strategy to search for ALPs with the Fermi satellite and current Cherenkov telescopes like CANGAROO, HESS, MAGIC and VERITAS.

4 pages, 4 figures. To appear in the proceedings of the "2nd Roma International Conference on Astroparticle Physics", Villa Mondragone, Rome, Italy, May 13-15 2009

References in corpus (13)

• An improved limit on the axion-photon coupling from the CAST experiment
• Evidence for a new light spin-zero boson from cosmological gamma-ray propagation?
• The Milky Way as a Kiloparsec-Scale Axionscope
• A High Resolution Search for Dark-Matter Axions
• Hints of the existence of Axion-Like-Particles from the gamma-ray spectra of cosmological sources
• Signatures of axion-like particles in the spectra of TeV gamma-ray sources
• VERITAS Observations of a Very High Energy Gamma-ray Flare from the Blazar 3C 66A
• Effects of Axion-Photon Mixing on Gamma-Ray Spectra from Magnetized Astrophysical Sources
• Discovery of a very high energy gamma-ray signal from the 3C 66A/B region
• Probing the 3.6 Micron CIRB with Spitzer in 3 DIRBE Dark Spots
• Angular Signatures of Dark Matter in the Diffuse Gamma Ray Background
• Constraints to Energy Spectra of Blazars based on Recent EBL Limits from Galaxy Counts
• Synchrotron Self-Compton Model for PKS 2155-304