Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stephan's Quintet: The X-ray Anatomy of a Multiple Galaxy Collision   Chandra observations of the compact galaxy group known as Stephan's Quintet
(SQ) are presented. The major morphological features that were discovered with
the ROSAT HRI are now imaged with higher resolution and S/N. The large scale
shock (1.5', ~40kpc if at 85 Mpc) is resolved into a narrow NS feature embedded
in more extended diffuse emission (D>=3'). The NS structure is somewhat clumpy,
more sharply bounded on the W side and prominent only in the soft band
(energies below ~2 keV). Its observational properties are best explained as a
shock produced by a high velocity encounter between NGC7318b, a ``new
intruder'', and the intergalactic medium in SQ. The shock conditions near the
high speed intruder suggest that a bow shock is propagating into a pre-existing
HI cloud and heating the gas to a temperature of ~0.5 keV. The low temperature
in the shock is a problem unless we postulate an oblique shock. One member,
NGC7319, hosts a Seyfert 2 nucleus, with an intrinsic luminosity Lx=10^43
erg/s, embedded in a region of more diffuse emission with 10'' radius extent.
The nuclear spectrum can be modeled with a strongly absorbed power-law typical
of this class of sources. Several additional compact sources are detected
including three in foreground NGC7320. Some of these sources are very luminous
and could be related to the ultraluminous X-ray sources found in nearby
galaxies.

34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat