A very deep Chandra observation of the Perseus cluster: shocks, ripples and conduction

Abstract

We present preliminary results from a deep observation lasting almost 200 ks, of the centre of the Perseus cluster of galaxies around NGC 1275. The X-ray surface brightness of the intracluster gas beyond the inner 20 kpc, which contains the inner radio bubbles, is very smooth apart from some low amplitude quasi-periodic ripples. A clear density jump at a radius of 24 kpc to the NE, about 10 kpc out from the bubble rim, appears to be due to a weak shock driven by the northern radio bubble. A similar front may exist round both inner bubbles but is masked elsewhere by rim emission from bright cooler gas. The continuous blowing of bubbles by the central radio source, leading to the propagation of weak shocks seen as the observed fronts and ripples, gives a rate of working which balances the radiative cooling within the inner 50 kpc of the cluster core.

Constraints on Feedback in the Local Universe: The Relation Between Star Formation and Agn Activity in Early-Type Galaxies

“…Observational evidence exists for AGN feedback in action in the BCGs in the form of X-ray cavities (McNamara & Nulsen 2007;Fabian 2012) and shocks (McNamara et al 2005;Fabian et al 2006;Forman et al 2007) in the ICM. Here we compare our sample with the BCGs in cool cores.…”

X-ray spectroscopy of galaxy clusters: studying astrophysical processes in the largest celestial laboratories

“…The model plotted with the red line shows the emission from the ambient hot ICM. Assuming a well calibrated instrument the excess line emission at ∼0.85 keV would be clearly revealed cooling cores, images obtained by Chandra reveal filaments and blobs in soft X-rays (Forman et al 2007;Fabian et al 2006). But the multi-phase extends to much lower temperatures.…”

“…But the multi-phase extends to much lower temperatures. Narrow band optical observations of cooling cores reveal Hα emitting warm (10 4 K) gas which both in M87 and in Perseus is often associated with soft X-ray filaments (Sparks et al 2004;Fabian et al 2006). The Hα filaments in Perseus are composed of gas with temperatures of 10 4 K down to 50 K (Hatch et al 2005).…”

“…As detailed in Fabian et al (2005) the dissipation of the sound waves-if the viscosity is sufficiently high-can balance the radiative cooling in the CC by heating with the realistic assumption that the sound waves cross the CC region in about 1/50 of the cooling time. Fabian et al (2006) have also carried out multi-temperature plasma modeling in various regions of the cluster center and produced mass distribution maps of plasma at temperatures around 0.5, 1, 2 and 4 keV. These maps are shown in comparison to a map of the optical Hα emission (observed by Conselice et al 2001) in Fig.…”

Metal Enrichment Processes

“…There is much observational evidence for AGN jets interacting with the ICM -not only radio jets but also cavities in the ICM found in X-rays (e.g. Blanton et al 2001;McNamara et al 2001;Schindler et al 2001;Heinz et al 2002;Choi et al 2004;Fabian et al 2006;McNamara & Nulsen 2007), in which the pressure of the relativistic particles of the jet has pushed away the ICM. The jets consisting of relativistic particles can entrain some of the surrounding metal-rich gas (De Young 1986).…”