Universal Peaks Ratio In The Spectral Energy Density Of Double Hump Blazars, Gamma Ray Bursts, And Microquasars

Abstract

The peak frequencies of the two broad humps evident in the spectral energy density of blazars (SED) are time dependent and vary a lot between different blazars. However, their ratio in most blazars, appears to be almost universal and equal to $m_e{c}^2/4(1+z){ϵ}_p$ to a good approximation, where $m_e$ is the electron mass, ${ϵ}_p$ is the peak energy of the cosmic microwave background radiation, and $z$ is the redshift of the blazar. We discuss a possible origin of such a universal ratio in blazars and gamma ray bursts (GRBs). We point out a possible connection between the knee in the energy spectrum of cosmic ray electrons and the maximal peak energies of the two broad humps in the SED of high-energy peaked blazars.

Comments: Accepted for publication in ApJL