090389

Every major modern hydrodynamical simulation suite now includes a prescription for AGN feedback to reproduce realistic populations of galaxies. However these simulations generally do not offer much insight into the nature of feedback. On the other hand the hot gas content of galaxy groups is highly sensitive to the implemented feedback scheme: the predicted gas fraction differs by an order of magnitude from one simulation to another. Here we propose to observe a sample of 40 galaxy groups exhibiting X-ray emission on scales and amp amp amp gt 12. with the aim of providing benchmark thermodynamic and gas fraction profiles out to R500 without requiring any extrapolation. The proposed program will gather a well controlled sample of systems spanning an order of magnitude in mass 1e13 and amp amp amp lt M500 and amp amp amp lt 1e14 Mo. [truncated! Please see actual data for full text]