2021 Project Description

Exploring dynamics and thermodynamic properties of diffuse X-ray emitting gas in galaxy clusters

Supervisors

Shutaro Ueda, Keiichi Umetsu
Find out more about supervisors on ASIAA website

Task Description and Goals

Galaxy clusters were being considered literally as a ``cluster of galaxies'' within a certain field in the sky, i.e., no or little material filling in intracluster space. However, X-ray observations discovered a large amount of diffuse X-ray emitting gas with temperature of 10^7-8 Kelvin (so-called intracluster medium) covering the whole field of individual clusters of galaxies for the first time. The estimated mass of the intracluster medium is about ~ 10^14 solar mass (i.e., ~ 10^44 kg), which is a factor of 2 - 3 larger than the total mass of galaxies in a cluster field. The intracluster medium is indeed a dominant component of baryons (i.e., ordinary matters) in the Universe!! The intracluster medium is trapped in the gravitational potential well of galaxy clusters dominated by dark matter. Therefore, the evolution of the intracluster medium is always coupled with that of galaxy clusters.

Recently, our team has discovered a gas motion of the intracluster medium in the core of high-mass galaxy clusters. This motion is considered to be associated with the evolution of galaxy clusters and to impact on thermodynamic properties of the intracluster medium. Therefore, in this project, we would like to extend this study to other galaxy clusters. In addition, we try to use specific radio observations of galaxy clusters so-called the Sunyaev-Zel'dovich effect, which are complementary to X-ray observations.

The first step of this project is aimed at understanding the current picture of galaxy clusters through X-ray observations (including how to use software for data analysis). To do that, the archival data of galaxy clusters taken by the Chandra X-ray Observatory will be used. In addition, we will use the datasets of the Sunyaev-Zel'dovich effect taken with the Planck satellite. Finally, this project will explore the gas dynamics and thermodynamic properties of the intracluster medium.

Example of X-ray and optical views of a galaxy cluster

Required Background

Passion for astrophysics