Active galactic nuclei (AGNs) exhibit variability across the entire electromagnetic spectrum with distinct flaring episodes at different frequencies. The high sensitivity and nearly uniform sky coverage of the Large Area Telescope on board the Fermi satellite make it a powerful tool for monitoring a large number of AGNs over long timescales. This allowed us to detect several flaring AGNs in gamma rays, triggering dedicated multifrequency campaigns on these sources from radio to TeV energies. We discuss the results for two different types of flaring AGN: the flat spectrum radio quasar 3C 279, in particular the coincidence of a gamma-ray flare from this source with the drastic change of the optical polarization angle, and the first gamma-ray flare from a radio-loud narrow-line Seyfert 1, PMN J0948+0022.
- Pub Date:
- December 2010
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- 6 pages, 2 figures. Invited talk presented at the Workshop "SciNeGHE 2010", September 8-10, 2010, Trieste, Italy. To appear in Il Nuovo Cimento C - Colloquia on physics. Title, Summary and Conclusions changed according to the referee's suggestion