Novel Methods of Measuring some Interesting Properties of Intergalactic Gas in Clusters

 

The Chandra X-ray Observatory's arcsecond angular resolution yielded discoveries of some unexpected (and some fully expected) sharp features in the hot intergalactic gas in clusters. We have observed two spectacular examples of shock fronts, as well as a much more common phenomenon of "cold fronts", which are sharp contact discontinuities arising when a cluster atmosphere with a steep radial entropy gradient is disturbed. These features can be used as novel tools for measuring some interesting quantities of the intracluster plasma, inaccessible by other means. I will show a test of the electron-ion equilibration timescale, two possible future tests of the intracluster magnetic field, and a possible test of plasma viscosity. Finally, I will show how to measure the helium abundance in the intracluster gas.

 

 

Maxim Markevitch