Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of coherent low-frequency radio bursts from weak-line TTauri
  stars   In recent years, thanks to new facilities such as LOFAR capable of sensitive
observations, much work has been done on the detection of stellar radio
emission at low frequencies. Such emission has commonly been shown to be
coherent emission, generally attributed to electron-cyclotron maser emission,
and has usually been detected from main-sequence M dwarfs. Here we report the
first detection of coherent emission at low frequencies from T Tauri stars,
which are known to be associated with high levels of stellar activity. Using
LOFAR, we have detected several bright radio bursts at 150 MHz from two
weak-line T Tauri stars: KPNO-Tau 14 and LkCa 4. All of the bursts have high
brightness temperatures ($10^{13} - 10^{14}\ \mathrm{K}$) and high circular
polarization fractions (60 - 90 \%), indicating that they must be due to a
coherent emission mechanism. This could be either plasma emission or
electron-cyclotron maser (ECM) emission. Due to the exceptionally high
brightness temperatures seen in at least one of the bursts ($\geq 10^{14}\
\mathrm{K}$), and the high circular polarization levels, it seems unlikely that
plasma emission could be the source and so ECM is favoured as the most likely
emission mechanism. Assuming this is the case, the required magnetic field in
the emission regions would be 40 - 70 G. We determine that the most likely
method of generating ECM emission is plasma co-rotation breakdown in the
stellar magnetosphere. There remains the possibility, however, it could be due
to an interaction with an orbiting exoplanet.

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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: nlin
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph