2023 Project Description

Ready for XRISM? - exploring thermal properties of diffuse, hot 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, hot 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. XRISM is a new generation X-ray astronomy satellite developed by JAXA and NASA, and is planning for launch in 2023 (this year!!). XRISM will carry two X-ray detectors, i.e., an X-ray micro calorimeter called Resolve and X-ray CCD camera called Xtend. Since the spectral energy resolution of Resolve is 30 times better than that of X-ray CCD cameras onboard the current working X-ray astronomy satellite, Resolve is strongly expected to obtain revolutionary data on all the X-ray emitting astronomical objects, in particular galaxy clusters. In this project, we aim at exploring gas dynamics and thermodynamic properties of the intracluster medium, and preparing a guest observer program of XRISM that is expected to start within 1 year after the launch. To do that, we will analyze the archival data of galaxy clusters obtained with the past and current working X-ray astronomy satellites and conduct spectral simulations for XRISM. Example of X-ray and optical views of a galaxy cluster

Required Background

Passion for astrophysics