Optical microvariability of EGRET blazars
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 display...
Saved in:
Published in | Astronomy and astrophysics (Berlin) Vol. 390; no. 2; pp. 431 - 438 |
---|---|
Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
EDP Sciences
01.08.2002
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | 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 is found 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 that observed in radio-selected BL Lacs and flat-spectrum radio quasars (i.e. ~70%). |
---|---|
Bibliography: | ark:/67375/80W-VV2G6RSQ-D Based on observations made at the Complejo Astronómico El Leoncito, which is operated under agreement between CONICET and the National Universities of La Plata, Córdoba, and San Juan. istex:12C25739F313F922DFE9BD77E8C16DF648E2CDF7 publisher-ID:aa2277 other:2002A%26A...390..431R |
ISSN: | 0004-6361 1432-0746 |
DOI: | 10.1051/0004-6361:20020743 |