Fermi Gamma-ray Space Telescope

Probing outflow and emission of a high redshift quasar

Juan-Carlos Algaba
(Bindu Rani)


Despite the intensive study of AGN, the location and origin of gamma-rays remains a mystery. A feature common to all high-energy emission models is that gamma-rays are expected to be associated with the compact regions of jets energized by the central black hole. We used multi-frequency observations of a high redshift blazar, 1633+382 (z=1.8), to constrain the location of gamma-ray emission region in the source. The study suggests a separation of 40 parsec between the gamma-ray and radio emitting sites, putting the location of gamma-ray emission region at a distance of ~1 parsec from the central black hole. Follow-up of the jet motion, speed, flux density and turnover frequency show that emission is in agreement with the shock-in-jet model adiabatically expanding with a constant Doppler factor.