Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bars and Boxy/Peanut-Shaped Bulges: An Observational Point of View   Prompted by work on the buckling instability in barred spiral galaxies, much
effort has been devoted lately to the study of boxy/peanut-shaped (B/PS)
bulges. Here, we present new bar diagnostics for edge-on spiral galaxies based
on periodic orbits calculations and hydrodynamical simulations. Both approaches
provide reliable ways to identify bars and their orientations in edge-on
systems. We also present the results of an observational search for bars in a
large sample of edge-on spirals with and without B/PS bulges. We show that most
B/PS bulges are due to the presence of a thick bar viewed edge-on while only a
few may be due to accretion. This strongly supports the bar-buckling mechanism
for the formation of B/PS bulges.

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The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: patt-sol
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th