Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A panoramic view of the Milky Way analogue NGC 891   Recent panoramic observations of the dominant spiral galaxies of the Local
Group have revolutionized our view of how these galaxies assemble their mass.
However, it remains completely unclear whether the properties of the outer
regions of the Local Group large spirals are typical. Here, we present the
first panoramic view of a spiral galaxy beyond the Local Group, based on the
largest, contiguous, ground-based imaging survey to date resolving the stellar
halo of the nearest prime analogue of the Milky Way, NGC 891 (D~10 Mpc). The
low surface brightness outskirts of this galaxy are populated by multiple,
coherent, and vast substructures over the 90kpc * 90kpc extent of the survey.
These include a giant stream, the first to be resolved into stars beyond the
Local Group using ground-based facilities, that loops around the parent galaxy
up to distances of ~50kpc. The bulge and the disk of the galaxy are found to be
surrounded by a previously undetected large, flat and thick cocoon-like stellar
structure at vertical and radial distances of up to ~15kpc and ~40kpc
respectively.

31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat