Optical microvariability of EGRET blazars
Abstract
We present results of a photometric CCD study of the incidence of microvariability in the optical emission of a sample of 20 blazars detected at gamma-ray energies by the EGRET instrument of the Compton Gamma-Ray Observatory. We have observed strong outbursts in some sources, but many others displayed no significant variability on timescales of hours. The typical minimum timescale results to be of ~ several hours, not tens of minutes as claimed by some authors. The duty cycle for optical intranight microvariations of gamma-ray blazars, as estimated from our observations, seems to be ~50%, lower than what is usually assumed. For night-to-night variations, instead, the duty cycle approaches to what is observed in radio-selected BL Lacs and flat-spectrum radio quasars (i.e. ~70%).
Cite
@article{arxiv.astro-ph/0205311,
title = {Optical microvariability of EGRET blazars},
author = {G. E. Romero and S. A. Cellone and J. A. Combi and I. Andruchow},
journal= {arXiv preprint arXiv:astro-ph/0205311},
year = {2009}
}
Comments
16 pages. Figure 2.1-20 (sent as JPEG files) will appear only in the electronic version. Accepted for publication in Astronomy & Astrophysics