dust-to-gas ratio and dust-to-metal ratio [in nearby galaxies]{}. Since the above change in the grain size distribution occurs in $t\sim 1$ Gyr, the age and density dependence of grain size distribution has a significant impact on the extinction curves even at high redshift.'
author:
- |
    Shohei Aoyama,$^{1}$[^1] Hiroyuki Hirashita,$^{1}$ and Kentaro Nagamine$^{2,3,4}$\
    $^{1}$ Institute of Astronomy and Astrophysics, Academia Sinica, Astronomy-Mathematics Building, AS/NTU, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan\
    $^{2}$ Theoretical Astrophysics, Department of Earth & Space Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan\
    $^{3}$ Kavli IPMU (WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8583, Japan\
    $^{4}$ Department of Physics & Astronomy, University of Nevada, Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV 89154-4002, USA
bibliography:
- 'ken.bib'
date: 'Last updated \*\*\*'
title: Galaxy simulation with the evolution of grain size distribution
---

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methods: numerical – dust, extinction – galaxies: evolution – galaxies: ISM – galaxies: spiral.

Introduction
============

Dust grains contained in the interstellar medium (ISM) evolve together with galaxies. Dust plays an important role at various stages of galaxy evolution in the following aspects. Molecular hydrogen, which is the main constituent of molecular clouds, forms on dust surfaces. 