Loud Active Galactic Nuclei Research Articles

The Evolution of Gamma-Ray--loud Active Galactic Nuclei

view Abstract Citations (86) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Evolution of Gamma-Ray--loud Active Galactic Nuclei Chiang, J. ; Fichtel, C. E. ; von Montigny, C. ; Nolan, P. L. ; Petrosian, V. Abstract During the period from the launch of the Compton Observatory in 1991 April through 1993 September, the Energetic Gamma-Ray Experiment Telescope (EGRET) has detected, with high significance (>5σ), 33 blazar-type QSOs which are sources of high-energy gamma-rays and another eight which show strong evidence for high-energy gamma-ray emission. Many of the gamma-ray loud blazars have redshifts z ∼ 1 with the most distant source having a redshift of z = 2.2. The V/VMAX test has been applied to the sample of gamma-ray loud AGNs seen during the phase I and II observing periods, and evidence for the evolution of these sources consistent with pure luminosity evolution is presented. The effects of observational biases due to gamma-ray flux-detection limits and optical identifications are considered. Using the Ve/Va test, we find the parameters describing the evolution, and by de-evolving the sample, we make an estimate of the luminosity function of these objects. Finally, using this luminosity function, we make an estimate of the gamma-ray loud AGN contribution to the diffuse extragalactic emission. Publication: The Astrophysical Journal Pub Date: October 1995 DOI: 10.1086/176287 Bibcode: 1995ApJ...452..156C Keywords: GALAXIES: ACTIVE; GAMMA RAYS: OBSERVATIONS; GALAXIES: QUASARS: GENERAL full text sources ADS | data products SIMBAD (41) NED (41) HEASARC (1) Related Materials (1) Erratum: 1996ApJ...465.1011C

High energy gamma rays from active galactic nuclei

Orders of magnitude and the basic processes associated with Active Galactic Nuclei (AGN) are outlined. Particular emphasis is given on the recent high energy (100 MeV–1 TeV) γ-ray observations from radio loud AGN and is argued that AGN can, in principle, be the sites of acceleration of particles to energies in excess of 1 TeV. It is indicated that the observed γ-ray emission cannot originate in a stationary plasma but from plasma in bulk relativistic motion with Γ ≳ 10 and arguments are given as to the dynamical origin of such relativistic outflows.