Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Toward First-Principle Simulations of Galaxy Formation: II.
  Shock-Induced Starburst at a Collision Interface During the First Encounter
  of Interacting Galaxies   We investigated the evolution of interacting disk galaxies using
high-resolution $N$-body/SPH simulations, taking into account the multiphase
nature of the interstellar medium (ISM). In our high-resolution simulations, a
large-scale starburst occurred naturally at the collision interface between two
gas disks at the first encounter, resulting in the formation of star clusters.
This is consistent with observations of interacting galaxies. The probability
distribution function (PDF) of gas density showed clear change during the
galaxy-galaxy encounter. The compression of gas at the collision interface
between the gas disks first appears as an excess at $n_{\rm H} \sim 10{\rm
cm^{-3}}$ in the PDF, and then the excess moves to higher densities ($n_{\rm H}
\gtrsim 100{\rm cm^{-3}}$) in a few times $10^7$ years where starburst takes
place. After the starburst, the PDF goes back to the quasi-steady state. These
results give a simple picture of starburst phenomena in galaxy-galaxy
encounters.

14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat