Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magic constraints on Gamma-ray emission from Cygnus X-3   Cygnus X-3 is a microquasar consisting of an accreting compact object
orbiting around a Wolf-Rayet star. It has been detected at radio frequencies
and up to high-energy gamma rays (above 100 MeV). However, many models also
predict a very high energy (VHE) emission (above hundreds of GeV) when the
source displays relativistic persistent jets or transient ejections. Therefore,
detecting such emission would improve the understanding of the jet physics. The
imaging atmospheric Cherenkov telescope MAGIC observed Cygnus X-3 for about 70
hours between 2006 March and 2009 August in different X-ray/radio spectral
states and also during a period of enhanced gamma-ray emission. MAGIC found no
evidence for a VHE signal from the direction of the microquasar. An upper limit
to the integral flux for energies higher than 250 GeV has been set to 2.2 x
10-12 photons cm-2 s-1 (95% confidence level). This is the best limit so far to
the VHE emission from this source. The non-detection of a VHE signal during the
period of activity in the high-energy band sheds light on the location of the
possible VHE radiation favoring the emission from the innermost region of the
jets, where absorption is significant. The current and future generations of
Cherenkov telescopes may detect a signal under precise spectral conditions.

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The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
1
The categories of this paper are: cs
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The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat