The Evolution of Swift/BAT blazars and the origin of the MeV background

Understand

We use 3 years of data from the Swift/BAT survey to select a complete sample of X-ray blazars above 15 keV.

• This sample comprises 26 Flat-Spectrum Radio Quasars (FSRQs) and 12 BL Lac objects detected over a redshift range of 0.03<z<4.0.
• We use this sample to determine, for the first time in the 15--55 keV band, the evolution of blazars.
• We find that, contrary to the Seyfert-like AGNs detected by BAT, the population of blazars shows strong positive evolution.