We present ROSAT observations of two luminous ( L _ { x } \sim 10 ^ { 44 } ) ~ { } erg~ { } s ^ { -1 } EMSS galaxies , MS1019+5139 and MS1209+3917 , previously classified as ’ cooling flow ’ galaxies .
MS1019+5139 does not appear to be spatially extended ( < 13 kpc ) while its spectrum is well fit by a power law with \Gamma = 1.73 ^ { +0.19 } _ { -0.18 } ; X-ray variability on a timescale of \sim years is also clearly detected .
MS1209+3917 shows no evidence of spatial extension ( < 50 kpc ) but it shows variability , while its spectrum can be fit with thermal bremsstrahlung emission ( kT = 1.8 ^ { +0.9 } _ { -0.4 } keV ) or a power law model ( \Gamma = 2.50 ^ { +0.44 } _ { -0.42 } , but with excess photoelectric absorption above the Galactic value ) .
All the above 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 .