Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Arp 119: A High Speed Galaxy Collision with Episodic Star Formation   Colliding galaxies are excellent laboratories for studying galactic evolution
and global star formation. Computer simulations of galaxy collisions, in which
at least one galaxy has a significant gaseous component, show the production of
density enhancements and shock waves in the interstellar medium. These
high-density regions coincide with the locations of recent, large-scale star
formation in observations of some real colliding galaxies. Thus, combined
n-body/hydrodynamic computer simulations can be used to explore the history and
conditions of star forming regions in colliding galaxies. The galaxy system Arp
119 (CPG 29) contains a southern member, Arp 119S (Mrk 984), that has an
extremely disturbed appearance, and a northern member, Arp 119N, a gas-poor
elliptical. The morphology of both members can be fit well by a simulation in
which a gas-rich disk galaxy has been impacted by an equal mass elliptical that
had a trajectory approximately perpendicular to the plane of the disk and
passed through the disk slightly off-center. We compare multi-wavelength
observations of the Arp 119 system with a combined n-body/SPH simulation of
colliding galaxies. We find that the progression of recent, large-scale star
formation in this galaxy can be accounted for by a single, outwardly
propagating collision-induced density wave in the gas.

34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex