Aug 20 – 25, 2023
Universität Hamburg
Europe/Berlin timezone

Constraints on axionlike particles from a combined Fermi-LAT analysis of flaring flat-spectrum radio quasars

Aug 21, 2023, 9:18 AM
Raum W221 (West Wing)

Raum W221

West Wing

Edmund-Siemers-Allee 1 Flügelbau West
Parallel session talk Astroparticle Physics and Gravitational Waves T01 Astroparticle Physics and Gravitational Waves


Manuel Meyer (University of Southern Denmark)


Axionlike particles (ALPs) are predicted in many extensions of the Standard Model and are viable dark matter candidates. These particles could mix with photons in the presence of a magnetic field. Searching for the effects of ALP-photon mixing in gamma-ray observations of blazars has provided some of the strongest constraints on ALP parameter space so far. For the first time, we perform a combined analysis on Fermi Large Area Telescope data of three bright flaring flat-spectrum radio quasars, with the blazar jets themselves as the dominant mixing region. We include a full treatment of photon-photon dispersion within the jet and account for the uncertainty in our B-field model by leaving the field strength free in the fitting. Overall, we find no evidence for ALPs but are able to exclude the photon-ALP couplings > 5e-12 / GeV for ALP masses between 5 neV and 200 neV with 95% confidence. In this mass region, these are the strongest bounds on the photon-ALP coupling to date from gamma-ray observations.

Collaboration / Activity Fermi-LAT collaboration

Primary authors

Prof. Garret Cotter (University of Oxford) Dr James Davies (University of Oxford) Manuel Meyer (University of Southern Denmark)

Presentation materials