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Optical microvariability of EGRET blazars

G. E. Romero·S. A. Cellone·J. A. Combi·I. Andruchow
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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%).

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G. E. Romero, S. A. Cellone, J. A. Combi, I. Andruchow. 2002-05-17. Optical microvariability of EGRET blazars. https://doi.org/10.1051/0004-6361%3A20020743

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