ROSAT observations of two 'cooling flow' EMSS galaxies

We present ROSAT observations of two luminous (L-x similar to 10(44)erg s(-1)) EMSS galaxies, MS 1019 + 5139 and 1209 + 3917, previously classified as 'cooling flow' galaxies. MS 1019 + 5139 does not appear to be spatially extended (sigma < 13 kpc), while its spectrum is well fitted by a power law with Gamma=1.73(-0.18)(+0.19), X-ray variability on a time-scale of similar to years is also clearly detected. MS 1209 + 3917 shows no evidence of spatial. extension (sigma < 50 kpc), but it shows variability; its spectrum can be fitted with thermal-bremsstrahlung emission (kT = 1.8(-0.4)(+0.9) keV) or a power-law model (Gamma = 2.50(-0.42)(+0.44), but with excess photoelectric absorption above the Galactic value). All the above facts argue against thermal emission from a group of galaxies or a galaxy, but in favour of an AGN (possibly BL Lac) interpretation. We conclude that no 'normal' galaxies with high X-ray luminosities have yet been detected in the EMSS survey that could be significant contributors to the X-ray background.