We also confirmed a resonant scattering signature in the Fe ${\rm_{XV\hspace{-.1em}I\hspace{-.1em}I}}$ line in the central region, as previously reported using the XMM-Newton RGS.'
author:
- |
    Katsuhiro H$^1$, Yasushi F$^1$, Miyako T$^1$\
    Sho N$^1$, Kyoko M$^2$, Yoh T$^3$,and Keith A. A$^{4,5}$\
    *\
    *\
    *\
    *\
    *\
    *******
title: |
    Suzaku Observation of the Metallicity Distribution\
    in the Elliptical Galaxy NGC 4636
---

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

The universe is filled with matter in various physical states. One of these is the hot interstellar medium (ISM) in elliptical galaxies. The ISM is gravitationally bound by the mass of stars, dark matter and itself, and its temperature is about 0.5–1 keV. Emission from the ISM is observed in the X-ray band and its luminosity reaches about 10$^{39}$–10$^{42}$ erg s$^{-1}$. By accurate analysis of X-ray spectra, we can estimate the temperature and metallicity distributions of the ISM and reveal the metal enrichment history of the universe.

In the past, X-ray imaging detectors, such as Chandra ACIS or XMM-Newton EPIC, have observed the ISM with high angular resolution and high signal-to-noise ratio (S/N) or wide field of view, and revealed temperature structures, surface brightness and mass distributions (e.g., Buote 2002; Buote et al. 2003; Fukazawa et 