Search for Spectral Irregularities due to Photon-Axionlike-Particle Oscillations With the Fermi Large Area Telescope

TL;DR

This study searches for spectral irregularities caused by photon-axionlike-particle oscillations in gamma-ray data from NGC 1275 using six years of Fermi LAT observations, finding no evidence and setting new constraints.

Contribution

It provides the first search for ALP-induced spectral irregularities in gamma-ray spectra with Fermi LAT data, establishing competitive exclusion limits on ALP parameters.

Findings

No evidence for ALP-induced spectral irregularities.

Excluded ALP-photon couplings above 5×10⁻¹² GeV⁻¹ for certain masses.

Set constraints comparable to planned laboratory experiments.

Abstract

We report on the search for spectral irregularities induced by oscillations between photons and axionlike-particles (ALPs) in the $\gamma$-ray spectrum of NGC 1275, the central galaxy of the Perseus cluster. Using six years of Fermi Large Area Telescope data, we find no evidence for ALPs and exclude couplings above $5\times10^{-12}\,\mathrm{GeV}^{-1}$ for ALP masses $0.5 \lesssim m_a \lesssim 5$ neV at 95% confidence. The limits are competitive with the sensitivity of planned laboratory experiments, and, together with other bounds, strongly constrain the possibility that ALPs can reduce the $\gamma$-ray opacity of the Universe.