Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolution of the X-Ray Jets from 4U 1755--33   We report on new X-ray observations of the large-scale jets recently
discovered in X-rays from the black hole candidate 4U 1755-33. Our observations
in 2004 show that the jets found in 2001 are still present in X-rays. However,
sensitive radio observations in 2004 failed to detect the jets. We suggest that
synchrotron radiation is a viable emission mechanism for the jets and that
thermal bremsstrahlung and inverse-Compton emission are unlikely on energetic
grounds. In the synchrotron interpretation, the production of X-rays requires
acceleration of electrons up to ~ 60 TeV, the jet power is ~ 4x10^35 erg s^-1,
and the radio non-detection requires a spectral index alpha > -0.65 (S_\nu
\propto \nu^\alpha) which is similar to the indexes found in lobes surrounding
some other compact objects. We find an upper limit on the flux of 4U 1755-33 in
quiescence of 5x10^-16 erg cm^-2 s^-1 in the 0.3-8 keV band.

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The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
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The categories of this paper are: supr-con
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn