Astronomy Tea Talk

The intracluster medium (ICM) velocity structure is important to understand cluster physics for several reasons: it affects the cluster mass estimates, help to constrain AGN feedback models, can probe the viscosity of the gas, regulate the transport of metals within the ICM and directly measure the sloshing of gas in cold fronts. However, there are few direct measurements of the ICM velocity structure, despite its importance for understanding cluster physics. In this talk I will present the analysis of long exposure XMM-Newton X-ray observations of the Virgo, Coma, Perseus, Ophiuchus and Centaurus galaxy clusters. We applied a novel technique which consist of using background X-ray lines seen in the spectra of the XMM-Newton EPIC-pn detector to calibrate the absolute energy scale of the detector to obtain velocity measurements with unprecedented accuracy down to 100 km/s. Using this technique, we have found signatures for AGN outflows and/or gas sloshing in our galaxy clusters sample.