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arXiv · 1511.03380

Axion-photon Propagation in Magnetized Universe

Chen Wang·Dong Lai
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Abstract

Oscillations between photons and axion-like particles (ALP) travelling in intergalactic magnetic fields have been invoked to explain a number of astrophysical phenomena, or used to constrain ALP properties using observations. One example is the anomalous transparency of the universe to TeV gamma-rays. The intergalactic magnetic field is usually modeled as patches of coherent domains, each with a uniform magnetic field, but the field orientation changes randomly from one domain to the next ("discrete-$φ$ model"). We show in this paper that in more realistic situations, when the magnetic field direction varies continuously along the propagation path, the photon-to-ALP conversion probability $P$ can be significantly different from the discrete-$φ$ model. In particular, $P$ has a distinct dependence on the photon energy and ALP mass, and can be as large as 100 percent. This result may affect previous constraints on ALP properties based on ALP-photon propagation in intergalactic magnetic fields.

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Chen Wang, Dong Lai. 2016-05-26. Axion-photon Propagation in Magnetized Universe. https://doi.org/10.1088/1475-7516%2F2016%2F06%2F006

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