# HG changeset patch
# User Nathan Goldbaum <ngoldbau@illinois.edu>
# Date 1511816320 18000
#      Mon Nov 27 15:58:40 2017 -0500
# Node ID 2359460e509d859471bbfe2dd26f5478cc0ed902
# Parent  ad6c03d7a68e081901275e6974dee7c5a8e24a69
add scientific justification for isogal sims

diff --git a/manuscript.tex b/manuscript.tex
--- a/manuscript.tex
+++ b/manuscript.tex
@@ -2033,6 +2033,24 @@
 \subsection{AGORA isolated disk galaxy: GAMER-2 vs. Enzo}
 \label{subsec:agora}
 
+Simulations of the gas, stars, and dark matter in a idealized isolated disk
+galaxy present a unique numerical challenge for astrophysical simulation
+codes. These simulations combine self-gravity, gas dynamics, particle dynamics
+with particles existing at a range of masses, radiative cooling, and star
+formation. In addition, gas temperatures may reach as low as $10\,{\rm K}$, but
+have a velocity relative to the simulation box of hundreds of kilometers per
+second, requiring the use of a dual energy formalism to avoid spurious
+temperature fluctuations and negative temperatures due to truncation error. On
+top of the bulk circular velocity, the gas also exhibits supersonic turbulence
+driven by gravitational instability \citep{Goldbaum2015}. Despite these
+challenges, isolated disk galaxy simulations are commonly used to understand
+more complicated zoom-in simulations \citep{AGORA}, galaxy merger simulations
+\citep{Robertson2006} and as a testbed for physics modules that will be used in
+more realistic simulations. These simulations also allow {\it ab initio\/}
+exploration of the dynamics of the interstellar medium (ISM) of a galaxy much
+like the Milky Way \citep{Goldbaum2016}, enabling direct comparison with
+observations of the ISM of our own Galaxy.
+
 In this section, we simulate a Milky Way-sized isolated disk galaxy
 with star formation using both \gamer\ and \enzo, from which we
 demonstrate that, not only the physical results obtained by the two codes
diff --git a/ref.bib b/ref.bib
--- a/ref.bib
+++ b/ref.bib
@@ -1058,3 +1058,19 @@
    adsurl = {http://adsabs.harvard.edu/abs/2007MNRAS.378..245B},
   adsnote = {Provided by the SAO/NASA Astrophysics Data System}
 }
+
+@ARTICLE{Robertson2006,
+   author = {{Robertson}, B. and {Bullock}, J.~S. and {Cox}, T.~J. and {Di Matteo}, T. and 
+	{Hernquist}, L. and {Springel}, V. and {Yoshida}, N.},
+    title = "{A Merger-driven Scenario for Cosmological Disk Galaxy Formation}",
+  journal = {\apj},
+   eprint = {astro-ph/0503369},
+ keywords = {Galaxies: Evolution, Galaxies: Formation},
+     year = 2006,
+    month = jul,
+   volume = 645,
+    pages = {986-1000},
+      doi = {10.1086/504412},
+   adsurl = {http://adsabs.harvard.edu/abs/2006ApJ...645..986R},
+  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
+}
\ No newline at end of file