Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Shock-Induced Pair of Superbubbles in the High-Redshift Powerful Radio
  Galaxy MRC 0406-244   We present new optical spectroscopy of the high-redshift powerful radio
galaxy MRC 0406$-$244 at redshift of 2.429. We find that the two extensions
toward NW and SE probed in the rest-frame ultraviolet image are heated mainly
by the nonthermal continuum of the active galactic nucleus. However, each
extension shows a shell-like morphology, suggesting that they are a pair of
superbubbles induced by the superwind activity rather than by the interaction
between the radio jet and the ambient gas clouds. If this is the case, the
intense starburst responsible for the formation of superbubbles could occur
$\sim 1 \times 10^9$ yr ago. On the other hand, the age of the radio jets may
be of the order of $\sim 10^6$ yr, being much shorter than the starburst age.
Therefore, the two events, i.e., the starburst and the radio-jet activities,
are independent phenomena. However, their directions of the expanding motions
could be governed by the rotational motion of the gaseous component in the host
galaxy. This idea appears to explain the alignment effect of MRC 0406$-$244.

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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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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: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: dg-ga