Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Planetary nebulae and their mimics: the MASH-MEN Project   The total number of true, likely and possible planetary nebulae (PN) now
known in the Milky Way is about 3000, approximately twice the number known a
decade ago. The new discoveries are a legacy of the recent availability of
wide-field, narrowband imaging surveys, primarily in the light of H-alpha. The
two most important are the AAO/UKST SuperCOSMOS H-alpha survey - SHS and the
Isaac Newton photometric H-alpha survey - IPHAS, which are responsible for most
of the new discoveries. A serious problem with previous PN catalogues is that
several different kinds of astrophysical objects are able to mimic PN in some
of their observed properties leading to significant contamination. These
objects include H II regions and Stromgren zones around young O/B stars,
reflection nebulae, Wolf-Rayet ejecta, supernova remnants, Herbig-Haro objects,
young stellar objects, B[e] stars, symbiotic stars and outflows, late-type
stars, cataclysmic variables, low redshift emission-line galaxies, and even
image/detector flaws. PN catalogues such as the Macquarie/AAO/Strasbourg
H-alpha Planetary Nebula catalogue (MASH) have been carefully vetted to remove
these mimics using the wealth of new wide-field multi-wavelength data and our
100% follow-up spectroscopy to produce a compilation of new PN discoveries of
high purity. During this process significant numbers of PN mimics have been
identified. The aim of this project is to compile these MASH rejects into a
catalogue of Miscellaneous Emission Nebulae (MEN) and to highlight the most
unusual and interesting examples. A new global analysis of these MEN objects is
underway before publishing the MEN catalogue online categorizing objects by
type together with their spectra and multi-wavelength images.

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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: eess
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The categories of this paper are: stat
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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: funct-an
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex