Cold fronts and multi-temperature structures in the core of Abell 2052

Abstract

Context. The physics of the coolest phases in the hot intra-cluster medium (ICM) of clusters of galaxies is yet to be fully unveiled. X-ray cavities blown by the central active galactic nucleus (AGN) contain enough energy to heat the surrounding gas and stop cooling, but locally blobs or filaments of gas appear to be able to cool to low temperatures of 10 4 K. In X-rays, however, gas with temperatures lower than 0.5 keV is not observed. Aims. We aim to find spatial and multi-temperature structures in the hot gas of the cooling-core cluster Abell 2052 that contain clues on the physics involved in the heating and cooling of the plasma. Methods. 2D maps of the temperature, entropy, and iron abundance are derived from XMM-Newton data of Abell 2052. For the spectral fitting, we use differential emission measure (DEM) models to account for the multi-temperature structure. Results. About 130 kpc South-West of the central galaxy, we discover a discontinuity in the surface brightness of the hot gas which is consistent with a cold front. Interestingly, the iron abundance jumps from ∼0.75 to ∼0.5 across the front. In a smaller region to the North-West of the central galaxy we find a relatively high contribution of cool 0.5 keV gas, but no X-ray emitting gas is detected below that temperature. However, the region appears to be associated with much cooler Hα filaments in the optical waveband. Conclusions. The elliptical shape of the cold front in the SW of the cluster suggests that the front is caused by sloshing of the hot gas in the clusters gravitational potential. This effect is probably an important mechanism to transport metals from the core region to the outer parts of the cluster. The smooth temperature profile across the sharp jump in the metalicity indicates the presence of heat conduction and the lack of mixing across the discontinuity. The cool blob of gas NW of the central galaxy was probably pushed away from the core and squeezed by the adjacent bubble, where it can cool efficiently and relatively undisturbed by the AGN. Shock induced mixing between the two phases may cause the 0.5 keV gas to cool non-radiatively and explain our non-detection of gas below 0.5 keV.

Feedback, scatter and structure in the core of the PKS 0745−191 galaxy cluster

“…Deep observations of several cooling flow clusters have shown that the picture of a complete cut off in the X-ray temperature distribution is incorrect. There are many cases now showing clusters with cool X-ray emitting gas embedded in a hotter medium, associated with emission line filaments, including Centaurus , Abell 2204, (Sanders, Fabian & Taylor 2009b), 2A 0335+096 (Sanders, Fabian & Taylor 2009a), Abell 2052(de Plaa et al 2010), M87 , Sérsic 159 (Werner et al 2011), Abell 262 and Abell 3581 (Sanders et al 2010) and in several elliptical galaxies (Werner et al 2014).…”

Violent interaction between the active galactic nucleus and the hot gas in the core of the galaxy cluster Sérsic 159−03

“…The relatively dense uplifted X-ray-emitting gas, which is removed from the direct influence of the AGN jets, will cool in the absence of heating and eventually form stars. Multiphase cooling X-ray gas, displaced from the centre of the cD galaxy and spatially coincident with Hα emission, has also been seen in the Ophiuchus Cluster, in Abell 2052 and in MACS J1931.8−2634 (Edwards et al 2009;de Plaa et al 2010;Million et al 2010b;Ehlert et al 2011).…”

Metal jumps across sloshing cold fronts: The case of A 496

“…However, relatively little attention has been paid to the metallicity properties of cold fronts (see, e.g., Simionescu et al 2010;de Plaa et al 2010), especially in the sloshing scenario of cool core clusters. These clusters have prominent metallicity peaks in their centers (e.g.…”