AGN Heating, Thermal Conduction, and the Sunyaev‐Zel'dovich Effect in Galaxy Groups and Clusters

Abstract

We investigate in detail the role of active galactic nuclei (AGN) on the physical state of the gas in galaxy groups and clusters, and the implications for anisotropy in the cosmic microwave background (CMB) from Sunyaev-Zeldovich (SZ) effect. We have recently showed that AGNs can significantly change the entropy of the intracluster medium (ICM) and explain the observations of excess entropy in groups and clusters. AGNs are assumed to deposit energy via buoyant bubbles which expand as they rise in the cluster atmosphere and do P dV work on the ICM. Here, we include the effect of thermal conduction, and find that the resulting profiles of temperature and entropy are consistent with observations. Unlike previously proposed models, our model predicts that isentropic cores are not an inevitable consequence of preheating. The model also reproduces the observational trend for the density profiles to flatten in lower mass systems.We deduce the energy E agn required to explain the entropy observations as a function of mass of groups and clusters M cluster and show that E agn ∝ M α cluster with α ∼ 1.5. We demonstrate that the entropy measurements, in conjunction with our model, can be translated into constraints on the cluster-black hole mass relation. The inferred relation is nonlinear and has the form M bh ∝ M α cluster . This scaling is an analog and extension of a similar relation between the black hole mass and the galactic halo mass that holds on smaller scales.In addition, we study the implications of these results for thermal SZ effect. We show that the central decrement of the CMB temperature is reduced due to the enhanced entropy of the ICM, and that the decrement predicted from the plausible range of energy input from the AGN is consistent with available data of SZ decrement. We also estimate the Poisson contribution to the angular power spectrum of the CMB from the SZ effect due to AGN heating. We show that AGN heating, combined with the observational constraints on entropy, leads to suppression of higher multipole moments in the power spectrum and we find that this effect is stronger than previously thought. The supression in the power spectrum in our model is due to depletion of gas from the central regions that is more efficient in low mass clusters and groups than in massive clusters.

Simulations of the Sunyaev-Zel'dovich Power Spectrum With Active Galactic Nucleus Feedback

“…Previously, an analytical model by Roychowdhury et al (2005) has explored the effects of effervescent heating on the SZ power spectrum and Holder et al (2007) use a semi-analytical model to calculate how an entropy floor affects the SZ power spectrum. There have been several simulations on galaxy and group scales that have studied how "quasar" feedback impacts the total SZ decrement (Thacker et al 2006;Scannapieco et al 2008;Bhattacharya et al 2008;Chatterjee et al 2008).…”

Filaments, Bubbles, and Weak Shocks in the Gaseous Atmosphere of M87

“…These bubbles can be a significant energy source for the cooling gas and can explain much of the radio and X-ray morphology (Churazov et al 2001Quilis et al 2001;Brüggen et al 2002). The energy of jets and buoyant bubbles can be transferred to the radiating gas by shocks, gravity waves, or turbulence (e.g., Churazov et al 2002;Ruszkowski et al 2004aRuszkowski et al , 2004bBegelman 2004;Omma et al 2004;Roychowdhury et al 2004Roychowdhury et al , 2005Heinz & Churazov 2005;Mathews et al 2006;Binney et al 2007). From deep Chandra observations of the Perseus Cluster, Fabian et al (2006) showed that pressure ripples could balance radiative cooling in the Perseus core, if the viscosity is high.…”

Little evidence for entropy and energy excess beyond r500 - An end to ICM preheating?

“…In contrast to preheating, there can also be in situ effects such as injection of energy feedback from AGN, radiative cooling, supernovae and star formation, influencing the thermal structure of ICM (Roychowdhury et al 2005;Pratt et al 2010;Eckert et al 2013a). There is growing evidence that AGN feedback mechanism provides a major source of heating for the ICM (McNamara & Nulsen 2007;Fabian 2012;Chaudhuri et al 2013) in the cluster cores.…”