Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multiband polarimetric and total intensity imaging of 3C345   We monitored the superluminal QSO 3C 345 at three epochs during a one-year
period in 1995--1996, observing with the VLBA at 22, 15, 8.4, and 5 GHz. We
imaged the radio source both in total and in polarized intensity. In the images
at 5 and 8.4 GHz, the jet emission is traced up to 20 milliarcseconds (mas)
from the jet core. In the 15 and 22 GHz images, we identify several enhanced
emission regions moving at apparent speeds of 5c. Images of the linear
polarized emission show predominantly an alignment of the electric vector with
the extremely curved jet along the inner part of the high frequency jet. At 5
GHz, the jet shows remarkably strong fractional polarization (m~15%) with the
electric vector perpendicular to the jet orientation.

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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: cond-mat
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The categories of this paper are: math
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The categories of this paper are: cs
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin