Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Planetary Nebulae distances in GAIA DR2   Context: Planetary Nebula distance scales often suffer for model dependent
solutions. Model independent trigonometric parallaxes have been rare. Space
based trigonometric parallaxes are now available for a larger sample using the
second data release of GAIA. Aims: We aim to derive a high quality approach for
selection criteria of trigonometric parallaxes for planetary nebulae and
discuss possible caveats and restrictions in the use of this data release.
Methods: A few hundred sources from previous distance scale surveys were
manually cross identified with data from the second GAIA data release (DR2) as
coordinate based matching does not work reliable. The data are compared with
the results of previous distance scales and to the results of a recent similar
study, which was using the first data release GAIA DR1. Results: While the few
available previous ground based and HST trigonometric parallaxes match
perfectly to the new data sets, older statistical distance scales, reaching
larger distances, do show small systematic differences. Restricting to those
central stars, were photometric colors of GAIA show a negligible contamination
by the surrounding nebula, the difference is negligible for radio flux based
statistical distances, while those derived from H-alpha surface brightness
still show minor differences. The DR2 study significantly improves the previous
recalibration of the statistical distance scales using DR1/TGAS.

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The categories of this paper are: atom-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-th
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The categories of this paper are: econ
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The categories of this paper are: cmp-lg