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Title: Extragalactic photon-ALP conversion at CTA energies

Magnetic fields in extragalactic space between galaxy clusters may induce conversions between photons and axion-like particles (ALPs), thereby shielding the photons from absorption on the extragalactic background light. For TeV gamma rays, the oscillation length (l osc) of the photon-ALP system becomes inevitably of the same order as the coherence length of the magnetic field l and the length over which the field changes significantly (transition length l t) due to refraction on background photons. We derive exact statistical evolution equations for the mean and variance of the photon and ALP transfer functions in the non-adiabatic regime (l osc ~ l >> l t). We also make analytical predictions for the transfer functions in the quasi-adiabatic regime (l osc <t). Our results are important in light of the upcoming Cherenkov Telescope Array (CTA), and may also be applied to models with non-zero ALP masses.
Authors:
 [1] ;  [1] ;  [2]
  1. Max-Planck-Inst. fur Physik, Munich (Germany)
  2. Max-Planck-Inst. fur Physik, Munich (Germany); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Report Number(s):
SLAC-PUB-16842
Journal ID: ISSN 1475-7516
Grant/Contract Number:
AC02-76SF00515; EXC 153; H2020-MSCAITN- 2015/674896-ELUSIVES
Type:
Accepted Manuscript
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2017; Journal Issue: 01; Journal ID: ISSN 1475-7516
Publisher:
Institute of Physics (IOP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE; German Research Foundation (DFG); European Union (EU)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; transparency of the Universe to high-energy photons; axion-like particles; photon-ALP conversion; photon-photon refraction; extragalactic magnetic fields
OSTI Identifier:
1360940

Kartavtsev, A., Raffelt, G., and Vogel, H.. Extragalactic photon-ALP conversion at CTA energies. United States: N. p., Web. doi:10.1088/1475-7516/2017/01/024.
Kartavtsev, A., Raffelt, G., & Vogel, H.. Extragalactic photon-ALP conversion at CTA energies. United States. doi:10.1088/1475-7516/2017/01/024.
Kartavtsev, A., Raffelt, G., and Vogel, H.. 2017. "Extragalactic photon-ALP conversion at CTA energies". United States. doi:10.1088/1475-7516/2017/01/024. https://www.osti.gov/servlets/purl/1360940.
@article{osti_1360940,
title = {Extragalactic photon-ALP conversion at CTA energies},
author = {Kartavtsev, A. and Raffelt, G. and Vogel, H.},
abstractNote = {Magnetic fields in extragalactic space between galaxy clusters may induce conversions between photons and axion-like particles (ALPs), thereby shielding the photons from absorption on the extragalactic background light. For TeV gamma rays, the oscillation length (losc) of the photon-ALP system becomes inevitably of the same order as the coherence length of the magnetic field l and the length over which the field changes significantly (transition length lt) due to refraction on background photons. We derive exact statistical evolution equations for the mean and variance of the photon and ALP transfer functions in the non-adiabatic regime (losc ~ l >> lt). We also make analytical predictions for the transfer functions in the quasi-adiabatic regime (losc <t). Our results are important in light of the upcoming Cherenkov Telescope Array (CTA), and may also be applied to models with non-zero ALP masses.},
doi = {10.1088/1475-7516/2017/01/024},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 01,
volume = 2017,
place = {United States},
year = {2017},
month = {1}
}