Evidence for a heated gas bubble inside the "cooling flow" region of MKW 3s

We report on the deep Chandra observation of the central r = 200 kpc region of the cluster of galaxies MKW 3s, which was previously identified as a moderate cooling flow cluster. The Chandra image reveals two striking features-a 100 kpc long and 21 kpc wide filament, extending from the center to the southwest, and a nearly circular, 50 kpc diameter depression 90 kpc south of the X-ray peak. The temperature map shows that the filamentary structure is colder while the surface brightness depression is hotter than the average cluster temperature at any radius. The hot and the cold regions indicate that both cooling and heating processes are taking place in the center of MKW 3s. We argue that the surface brightness depression is produced by a heated, low-density gas bubble along the line of sight. We suggest that the heated bubble is produced by short-lived nuclear outbursts from the central galaxy.