Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: RefPlanets: Search for reflected light from extra-solar planets with
  SPHERE/ZIMPOL   RefPlanets is a guaranteed time observation (GTO) programme that uses the
Zurich IMaging POLarimeter (ZIMPOL) of SPHERE/VLT for a blind search for
exoplanets in wavelengths from 600-900 nm. The goals of this study are the
characterization of the unprecedented high polarimetic contrast and
polarimetric precision capabilities of ZIMPOL for bright targets, the search
for polarized reflected light around some of the closest bright stars to the
Sun and potentially the direct detection of an evolved cold exoplanet for the
first time. For our observations of Alpha Cen A and B, Sirius A, Altair, Eps
Eri and Tau Ceti we used the polarimetric differential imaging (PDI) mode of
ZIMPOL which removes the speckle noise down to the photon noise limit for
angular separations >0.6". We describe some of the instrumental effects that
dominate the noise for smaller separations and explain how to remove these
additional noise effects in post-processing. We then combine PDI with angular
differential imaging (ADI) as a final layer of post-processing to further
improve the contrast limits of our data at these separations. For good
observing conditions we achieve polarimetric contrast limits of 15.0-16.3 mag
at the effective inner working angle of about 0.13", 16.3-18.3 mag at 0.5" and
18.8-20.4 mag at 1.5". The contrast limits closer in (<0.6") depend
significantly on the observing conditions, while in the photon noise dominated
regime (>0.6"), the limits mainly depend on the brightness of the star and the
total integration time. We compare our results with contrast limits from other
surveys and review the exoplanet detection limits obtained with different
detection methods. For all our targets we achieve unprecedented contrast
limits. Despite the high polarimetric contrasts we are not able to find any
additional companions or extended polarized light sources in the data that has
been taken so far.

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The categories of this paper are: cs
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int