Excess entropy and energy feedback from within cluster cores up to r${}_{200}$

Abstract

We estimate the "non-gravitational" entropy-injection profiles, $\Delta K$, and the resultant energy feedback profiles, $\Delta E$, of the intracluster medium for 17 clusters using their Planck SZ and ROSAT X-Ray observations, spanning a large radial range from $0.2r_{500}$ up to $r_{200}$. The feedback profiles are estimated by comparing the observed entropy, at fixed gas mass shells, with theoretical entropy profiles predicted from non-radiative hydrodynamic simulations. We include non-thermal pressure and gas clumping in our analysis. The inclusion of non-thermal pressure and clumping results in changing the estimates for $r_{500}$ and $r_{200}$ by 10\%-20\%. When clumpiness is not considered it leads to an under-estimation of $\Delta K\approx 300$ keV cm${}^2$ at $r_{500}$ and $\Delta K\approx 1100$ keV cm${}^2$ at $r_{200}$. On the other hand, neglecting non-thermal pressure results in an over-estimation of $\Delta K\approx 100$ keV cm${}^2$ at $r_{500}$ and under-estimation of $\Delta K\approx 450$ keV cm${}^2$ at $r_{200}$. For the estimated feedback energy, we find that ignoring clumping leads to an under-estimation of energy per particle $\Delta E\approx 1$ keV at $r_{500}$ and $\Delta E\approx 1.5$ keV at $r_{200}$. Similarly, neglect of the non-thermal pressure results in an over-estimation of $\Delta E\approx 0.5$ keV at $r_{500}$ and under-estimation of $\Delta E\approx 0.25$ keV at $r_{200}$. We find entropy floor of $\Delta K\approx 300$ keV cm${}^2$ is ruled out at $\approx 3\sigma$ throughout the entire radial range and $\Delta E\approx 1$ keV at more than 3$\sigma$ beyond $r_{500}$, strongly constraining ICM pre-heating scenarios. We also demonstrate robustness of results w.r.t sample selection, X-Ray analysis procedures, entropy modeling etc.

17 pages, 15 figures, 5 tables, Accepted in MNRAS