Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: CSI2264: Simultaneous optical and X-ray variability in the pre-main
  sequence stars of NGC2264. II: Photometric variability, magnetic activity,
  and rotation in classIII objects and stars with transition disks   Pre-main sequence stars are variable sources. In diskless stars this
variability is mainly due to the rotational modulation of dark photospheric
spots and active regions, as in main sequence stars even if associated with a
stronger magnetic activity. Aims. We aim at analyzing the simultaneous optical
and X-ray variability in these stars to unveil how the activity in the
photosphere is connected with that in the corona, to identify the dominant
surface magnetic activity, and to correlate our results with stellar
properties, such as rotation and mass. Methods. We analyzed the simultaneous
optical and X-ray variability in stars without inner disks (e.g., class III
objects and stars with transition disks) in NGC 2264 from observations obtained
with Chandra/ACIS-I and CoRoT as part of the Coordinated Synoptic Investigation
of NGC 2264. We searched for those stars whose optical and X-ray variability is
correlated, anti-correlated, or not correlated by sampling their optical and
X-ray light curves in suitable time intervals and studying the correlation
between the flux observed in optical and in X-rays. We then studied how this
classification is related with stellar properties. Results. Starting from a
sample of 74 class III/transition disk (TD) stars observed with CoRoT and
detected with Chandra with more than 60 counts, we selected 16 stars whose
optical and X-ray variability is anti-correlated, 11 correlated, and 17 where
there is no correlation. The remaining stars did not fall in any of these
groups. We interpreted the anti-correlated optical and X-ray variability as
typical of spot-dominated sources, due to the rotational modulation of
photospheric spots spatially coincident to coronal active regions, and
correlated variability typical of faculae-dominated sources, where the
brightening due to faculae is dominant over the darkening due to spots.
[Conclusions not shown in the pre-print]

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The categories of this paper are: q-alg
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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: q-bio
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The categories of this paper are: stat
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The categories of this paper are: nlin
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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: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con