Optical microvariability of EGRET blazars
Optical microvariability of EGRET blazars
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DOI：
10.1051/0004-6361:20020743
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发表时间：
2002-05
影响因子：
6.5
通讯作者：
G. Romero;S. Cellone;J. Combi;I. Andruchow
中科院分区：
文献类型：
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作者：
G. Romero;S. Cellone;J. Combi;I. Andruchow
我们提出的一个光度CCD的研究结果的发生率的微变的光发射的样品中检测到的伽玛射线能量的EGRET仪器的康普顿伽玛射线天文台的20耀变体。我们在一些源中观察到强烈的爆发，但许多其他源在小时的时间尺度上没有显示出显著的变化。典型的最小时间尺度结果是大约几个小时，而不是一些作者声称的几十分钟。根据我们的观测估计，γ射线耀变体的光学夜内微变的占空比似乎为1.50%，低于通常的假设。相反，对于夜间变化，占空比接近于在无线电选择BL拉克和平谱射电类星体中观察到的占空比（即70%）。
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 %).