Unraveling AGN feedback and ICM physics with deep Chandra X-ray observations of the galaxy group NGC 5813

We present results from deep Chandra X-ray observations of the galaxy group NGC 5813. This system shows three pairs of collinear cavities, with each pair associated with an elliptical AGN outburst shock. Due to the relatively regular morphology of this system, and the unique unambiguous detection of three distinct AGN outburst shocks, it is particularly well-suited for the study of AGN feedback and the AGN outburst history. We find that the mean kinetic power is roughly the same for each outburst, and that the total energy associated with the youngest outburst is significantly lower than that of the previous outbursts. This implies that the mean AGN jet power has remained stable for at least 50 Myr, and that the youngest outburst is ongoing. We find that the mean shock heating rate balances the local radiative cooling rate at each shock front, suggesting that AGN outburst shock heating alone is sufficient to offset cooling and establish AGN/ICM feedback within at least the central 30 kpc. Finally, we find non-zero shock front widths that are too large to be explained by particle diffusion, but are instead consistent with arising from broadening of the shock fronts due to propagation through a turbulent ICM with a mean turbulent speed of similar to 70 km s(-1).