The heated core of the radio-quiet galaxy cluster A644

We present an analysis of a Chandra ACIS-I observation of the massive galaxy cluster A644. This cluster was previously classified as a cooling flow, but no radio emission has been detected from its cD galaxy. Outside the core ( R similar to 75 kpc similar to 0: 03r(vir)) the hot ICM has properties consistent with a ( relaxed) cool-core cluster out to the largest radii investigated ( R similar to 415 kpc similar to 0: 14r(vir)). Over this region the gravitating mass profile is described well by a Navarro-Frenk-White (NFW) profile with concentration parameter c 6: 1 +/- 1: 2 and virial radius r(vir) 2: 9 similar to 0: 4 Mpc. However, inside the core the temperature and entropy profiles reverse their inward radial decline and rise at the center; the inner temperature profile is inconsistent with a constant at the 2.3 sigma level. Although the core region does not display X-ray cavities or filamentary structures characteristic of radio-loud, cool-core clusters, the peak of the X-ray emission is offset from that of the centroid of the global X-ray halo by approximate to 60 kpc. The position of the cD galaxy lies approximately between the X-ray peak and centroid, further testifying to a merger origin for the properties of the X-ray emission in the core. We discuss the implications of A644 and the small number of radio-quiet, cool-core clusters for the AGN feedback paradigm to suppress cooling flows in clusters.