The Complex Cooling Core of A2029: Radio and X-Ray Interactions

We present an analysis of Chandra observations of the central regions of the cooling flow cluster A2029. We find a number of X-ray filaments in the central 40 kpc, some of which appear to be associated with the currently active central radio galaxy. The outer southern lobe of the steep-spectrum radio source appears to be surrounded by a region of cool gas and is at least partially surrounded by a bright X-ray rim similar to that seen around radio sources in the cores of other cooling flow clusters. Spectroscopic fits show that the overall cluster emission is best fitted by either a two-temperature gas (kT_high = 7.47 keV and kT_low = 0.11 keV) or a cooling flow model with gas cooling over the same temperature range. This large range of temperatures (over a factor of 50) is relatively unique to A2029 and may suggest that this system is a very young cooling flow in which the gas has only recently started cooling to low temperatures. The cooling flow model gives a mass deposition rate of = 56 M_☉ yr^-1. In general, the cluster emission is elongated along a position angle of 22° with an ellipticity of 0.26. The distribution of the X-ray emission in the central region of the cluster is asymmetric, however, with excess emission to the northeast and southeast compared with that to the southwest and northwest, respectively. Fitting and subtracting a smooth elliptical model from the X-ray data reveals a dipolar spiral excess extending in a clockwise direction from the cluster core to radii of ~150 kpc. We estimate a total mass of M_spr ~ 6 × 10¹² M_☉ in the spiral excess. The most likely origin of the excess is either stripping of gas from a galaxy group or from bare dark matter potential that has fallen into the cluster or sloshing motions in the cluster core induced by a past merger.