We collect a sample of 381(271 type Ⅰ)active galactic nuclei(AGNs)with XMM-Newton observations for an analysis of the d......

We report on the optical color variability of a sample of 24 blazars,consisting of nine flat spectrum radio quasars (FSR......

POLAR is a compact space-borne detector initially designed to measure the polarization of hard X-rays emitted from Gamma......