Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fast Variations of Gamma-Ray Emission in Blazars   The largest group of sources identified by EGRET are Blazars. This sub-class
of AGN is well known to vary in flux in all energy bands on time-scales ranging
from a few minutes (in the optical and X-ray bands) up to decades (radio and
optical regimes). In addition to variations of the gamma-ray flux between
different viewing periods, the brightest of these sources showed a few
remarkable gamma-ray flares on time-scales of about one day, confirming the
extension of the ``Intraday-Variability (IDV)'' phenomenon into the GeV range.
We present first results of a systematic approach to study fast variability
with EGRET data. This statistical approach confirms the existence of IDV even
during epochs when no strong flares are detected. This provides additional
constraints on the site of the gamma-ray emission and allows cross-correlation
analyses with light curves obtained at other frequencies even during periods of
low flux. We also find that some stronger sources have fluxes systematically
above threshold even during quiescent states. Despite the low count rates this
allows explicit comparisons of flare amplitudes with other energy bands.

17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
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The categories of this paper are: stat