Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic Activity of Pre-main Sequence Stars near the Stellar-Substellar
  Boundary   X-ray observations of pre-main sequence (pre-MS) stars of M-type probe
coronal emission and offer a means to investigate magnetic activity at the
stellar-substellar boundary. Recent observations of main sequence (MS) stars at
this boundary display a decrease in fractional X-ray luminosity
($L_{X}$/$L_{bol}$) by almost two orders of magnitude for spectral types M7 and
later. We investigate magnetic activity and search for a decrease in X-ray
emission in the pre-MS progenitors of these MS stars. We present XMM-Newton
X-ray observations and preliminary results for ~10 nearby (30-70 pc), very low
mass pre-MS stars in the relatively unexplored age range of 10-30 Myr. We
compare the fractional X-ray luminosities of these 10-30 Myr old stars to
younger (1-3 Myr) pre-MS brown dwarfs and find no dependence on spectral type
or age suggesting that X-ray activity declines at an age later than ~30 Myr in
these very low-mass stars.

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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: math-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ph
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The categories of this paper are: math
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
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The categories of this paper are: patt-sol