X-ray measurements of cluster gas bulk motions

Talk in Alpine cosmology workshop

2013-06-25

abstract:
X-ray studies of velocity structures of the intracluster medium is one of the primary goals for future X-ray missions.
High resolution spectroscopy will provide measurements of energy distributions not only in thermal but also in kinematic forms.
These provide not only to understanding of cluster formation but also reductions of systematic uncertainties in cluster total masses for precise cosmology.
Using Suzaku we have detected a motion of a sub component with a velocity of about 1500 km/s for the first time by X-ray of a X-ray bright merging cluster, Abell2256 (Tamura et al. 2011).
We also searched for gas bulk motions in relaxed clusters such as the Perseus.
In addition we attempt to measure 'X-ray gas redshift' of clusters.
We found that gas are moving in pair with galaxies at least in X-ray bright central regions.
Studies of gas bulk motion along with turbulent motions will be drastically advanced by X-ray micro calorimeter onboard ASTRO-H to be launched in 2015. We will discuss the implications of current limits and future prospects.