Search for gamma rays from 3C 273 and M 87

Abstract

Upper limits are set to the γ-ray flux above 50 MeV from 3C 273 and M 87 of 1.1 × 10⁻⁵ and 1.0 × 10⁻⁵ γ cm⁻² s⁻¹ respectively. The value for 3C 273 is below the minimum predicted from the matter–antimatter model for quasars of 3 × 10⁻⁵ γ cm⁻² s⁻¹. The vertical γ-ray flux at 2.5 mbar and 20° geomagnetic latitude is 1.6 × 10⁻³ γ cm⁻² s⁻¹ sr⁻¹.