Multi-GeV photons from electron–dark-matter scattering near active galactic nuclei

Abstract

Active galactic nuclei (AGN) may emit highly collimated and intense jets of relativistic electrons which upscatter ambient photons. These electrons can also scatter off the cold dark matter halo of the galaxy to produce high energy photons which have a more isotropic signature than the upscattered photons from QED processes. We propose to look for these high energy photons coming from AGN as a method to detect dark matter. As a primary example we work out the expected signal from electrons scattering off the lightest supersymmetric partner into a photon plus selectron. Using the optimistic side of astrophysical uncertainties, we still find the signal from M87 or Centaurus A, two close-by AGN, smaller than the sensitivities expected of the currently proposed photon detectors. However, long running photon detectors and future detectors of higher sensitivity might be able to distinguish a signal from AGN sources. In order to have confidence that new physics sources are discernible, we also emphasize the importance of multiwavelength studies of AGN with varying jet axis orientation to the Earth.