Previous abstract Next abstract

Session 5 - High Luminosity AGN.
Display session, Monday, June 10
Tripp Commons,

[5.09] A Sudy of the Properties of the High-Energy Gamma-Ray Emitting Blazars seen by EGRET as a Function of whether they are BL Lacs or FSRQs

C. E. Fichtel, D. L. Bertsch, R. C. Hartman, S. D. Hunter, D. J. Thompson (NASA/GSFC), B. L. Dingus, J. A. Esposito, R. Mukherjee, P. Sreekumar (USRA, NASA/GSFC), Y. C. Lin, P. F. Michelson, P. L. Nolan (Stanford U.), G. Kanbach, H. Mayer-Hasselwander (Max Planck), D. A. Kniffen (Hampden-Sydney), C. von Montigny (Landessternwarte Koenigstuhl), E. Schneid (Northrop-Grumman)

Over fifty AGN have been have been observed to be emitting high-energy gamma-rays by EGRET on the Compton Gamma-Ray Observatory; all are blazars. Blazars are known to consist of two groups of objects, the BL Lacs and the FSRQs. In the radio range, the FSQRs are more luminous and more distant on the average. Although the sample of gamma-ray emitting blazars is rather small, an examination showes that the same is true of the high-energy gamma-ray emitting blazars and that, within the quite large uncertainty due to the limited statistics, the distributions in z are similar. The gamma-ray properites of the blazars have been examined again carefully, particularly in light of the best current correction factors. There is an indication that, when the spectra are compared to a power law in photon energy, the high-energy gamma-ray spectral slopes of the BL lacs may be slighly less negative than those of the FSRQ, i. e. the spectra appear to be harder. At the moment, these differences probably could be interpreted either as inherent differences or evolutionary effects, although the overlap of the distributions in z might be a mild arguement in favor of fundamental differences.

Program listing for Monday