A ROSAT HRI OBSERVATION OF THE COOLING FLOW CLUSTER MS0839.9+2938

A ROSAT HRI observation of the duster MS0839.9 + 2938 at Z = 0.194 is presented. It confirms the earlier suggestion, based on the detection of extended H alpha emission, that the inner regions of this cluster a re dominated by a cooling flow. Within the cooling radius a marginally significant evidence is found of structures in the surface brightness , which are similar to those more significantly found in two less dist ant cooling flow clusters (A2029 and 2A0335 + 096). We note that, alth ough its barycentre falls on top of the central giant elliptical galax y, the azimuthally averaged brightness distribution does not peak at t hat position and actually stays flat out to about 40 kpc (10'') from t he galaxy centre. From comparison with the two clusters mentioned abov e, this situation seems peculiar, and it is suggested that it could ar ise from photoelectric absorption by cold gas within the cooling flow, with an equivalent column density in the order of 5 x 10(21) cm(-2) w ithin similar to 10'' from the centre, a factor 2-3 higher than the co lumn spectroscopically detected in the comparison clusters.