AAS 202nd Meeting, May 2003
Session 18 Blazars and Radio Sources
Oral, Monday, May 26, 2003, 2:00-3:30pm, 204

## [18.06] Possible optical identification of gamma-ray blazars

R. Sefako (University of Wisconsin - Madison)

Observations have shown that extragalactic gamma-ray emitters are blazars, with mostly flat-spectrum radio quasars (FSRQs) and low frequency peaked BL Lacs (LBLs) detected at GeV (or EGRET) energies, whereas the nearby high frequency peaked BL Lacs (HBLs) are mainly detected at TeV energies by ground-based gamma-ray detectors. Although many factors (e.g. redshift and bolometric brightness) may play a role in possible gamma-ray detection, it has become clear that the position of the peak of the synchrotron emission frequency, \nup, is crucial in determining whether an observed blazar is likely to be detected at either GeV or TeV energies. This study looks at different ways of determining the position of \nup from optical observations, and therefore, explore possibilities of identifying TeV candidate blazars for future generation of gamma-ray telescopes. The detection of these candidate blazars at TeV energies will shed light on the particle acceleration mechanisms, as well as the understanding of the intergalactic IR-UV background radiation, which makes detection of high z objects at gamma-rays almost impossible.