Anya Chaudhuri, Subhabrata Majumdar, Biman B. Nath
AGN feedback is of primary importance in injecting energy in the central regions of galaxy clusters and influences the global properties the intra-cluster medium (ICM) . Comparing the observed entropy profiles, within $r_{500}$, from the Representative XMM-Newton Cluster Structure Survey (REXCESS) to profiles predicted by adiabatic simulations, we estimate the non-gravitational energy, $E_{ICM}$, contained in the ICM. Adding the radiative energy losses we estimate the total energy feedback, $E_{Feedback}$, from the AGN's (the central AGN in most cases). The profiles for $E_{ICM}$, $ \Delta E_{ICM}$ in the inner regions differ for Cool-Core (CC) and Non Cool-Core (NCC) clusters and assume a similar profile after accounting for the radiation loss in CC clusters. We propose that $\Delta E_{ICM}$ is a natural indicator of CC-vs-NCC clusters. The feedback energy scales with temperature as $E_{Feedback} \propto T_{sp}^{2.57}$ for the entire sample with a scatter of $\approx 14%$. The mean energy per particle within $R_{500}$ is $\epsilon_{ICM} (R_{500})= 2.54 \pm 0.78 keV $. We use the NRAO/VLA Sky Survey (NVSS) source catalog to determine the radio luminosity at 1.4 GHz of the central source(s) of our sample. $E_{Feedback}$ shows a strong correlation with $L_R$, with different normalizations for CC and NCC clusters above $T> 3$ keV, indicating that AGN feedback from the central galaxies may provide a significant component of the feedback. CC clusters show a greater $L_R$ for a given value of feedback energy than NCC clusters. Below this temperature $E_{Feedback}$ is however significantly lower for the same value of $L_R$ showing a lower efficiency of feedback. We study the properties of the brightest central galaxy (BCG) and find a mild correlation between the BCG heating rate and the feedback energy.
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http://arxiv.org/abs/1211.3817
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