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

James Davies, Manuel Meyer, Garret Cotter

Submitted on 7 November 2022


Many theories beyond the Standard Model of particle physics predict the existence of axionlike particles (ALPs) that 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. Previously, only individual sources have been analysed. 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. For the first time, 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 ALP parameters ma200 neV and gaγ5×1012 GeV1 with 95\% confidence.


Comment: 18 pages, 14 figures; submitted to Physical Review D

Subjects: Astrophysics - High Energy Astrophysical Phenomena; High Energy Physics - Phenomenology


SEDs for our sources during the flares: 3C454.3 (top), CTA 102 (middle), 3C279 (bottom). Best-fit spectral parameters (corresponding to the red lines) and time ranges used are listed in Table \ref{tab:flares}. Black points show detections and triangles show 95\% upper-limits. Shaded regions show the likelhood curves for each energy bin. For clarity, only points for every other energy bin are plotted.