Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The first detection of Far-Infrared emission associated with an extended
  HI disk. The case of NGC 891   Spiral galaxies in the Local Universe are commonly observed to be embedded in
extended disks of neutral hydrogen - the so called ``extended HI disks''. Based
on observations made using the ISOPHOT instrument on board the Infrared Space
Observatory, we report the first detection of cold dust in the extended HI disk
of a spiral galaxy. The detection was achieved through a dedicated deep
Far-Infrared observation of a large field encompassing the entire HI disk of
the edge-on spiral galaxy NGC 891. Our discovery indicates that the extended HI
disk of NGC 891 is not primordial in origin.

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The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
3
The categories of this paper are: physics