  We report on the deep Chandra observation of central r=200kpc region of the
cluster of galaxies MKW3s which was previously identified as a moderate cooling
flow cluster. The Chandra image reveals two striking features -- a 100kpc long
and 21kpc wide filament, extending from the center to the south-west and a
nearly circular, 50kpc 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 MKW3s. 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.
