Cross correlation of cosmic shear and extragalactic gamma-ray background: Constraints on the dark matter annihilation cross section

Masato Shirasaki, Shunsaku Horiuchi, Naoki Yoshida
2014 Physical Review D  
We present the first measurement of the cross-correlation of weak gravitational lensing and the extragalactic gamma-ray background emission using data from the Canada-France-Hawaii Lensing Survey and the Fermi Large Area Telescope. The cross-correlation is a powerful probe of signatures of dark matter annihilation, because both cosmic shear and gamma-ray emission originate directly from the same DM distribution in the universe, and it can be used to derive constraints on dark matter
more » ... cross-section. We show that the measured lensing-gamma correlation is consistent with a null signal. Comparing the result to theoretical predictions, we exclude dark matter annihilation cross sections of =10^-24-10^-25 cm^3 s^-1 for a 100 GeV dark matter. If dark matter halos exist down to the mass scale of 10^-6 M_sun, we are able to place constraints on the thermal cross sections 3 x 10^-26 cm^3 s^-1 for a 10 GeV dark matter annihilation into tau^+ tau^-. Future gravitational lensing surveys will increase sensitivity to probe annihilation cross sections of 5 x 10^-26 cm^3 s^-1 even for a 100 GeV dark matter. Detailed modeling of the contributions from astrophysical sources to the cross correlation signal could further improve the constraints by 40-70
doi:10.1103/physrevd.90.063502 fatcat:g77blxqbi5hnbc6vnjw5twc4u4