Mapping the Nearest Ancient Sloshing Cold Front in the Sky

We have been awarded three XMM-Newton EPIC observations totaling 102 ksec to map a sloshing cold front at the large radius of the Virgo Cluster that is previously discovered by Suzaku. The proposed observation will characterize its properties significantly more accuracy than was achieved with Suzaku. We will measure the surface brightness, temperature, and pressure profiles across the front to test the suppression of fluid instabilities in the ICM and to probe the evolution of the sloshing cold front over the past few billion years. The European Space Agency has evaluated the scientific and technical merits of our proposal and gives it a priority of A. The fair-share estimate given by the U.S. XMM-Newton Guest Observer Facility is $76696. Cold fronts are discontinuities in X-ray surface brightness separating gas of different entropies. The survival of cold fronts at large radii of the intracluster medium can put strong constraints on the strength of the cluster plasma physics but they are also much fainter that cold fronts typically found at cluster centers. Our project will involve careful modeling of XMM’s unstable particle background as well as various sources of astrophysical backgrounds such as cosmic X-ray background and the galactic foreground. We will also perform both imaging and spectral analysis with the proposed observations. It is also necessary to deproject the gas property profiles to obtain the relative strength of the thermal pressure and the magnetic pressure. This project therefore involves complicated data reduction and analysis. We plan to finish this project within one year. 1