We present ROSAT HRI and ASCA observations of the well known ULIRG IRAS19254-7245 ( the Superantennae ) .
The object is not detected by ROSAT yielding a 3 \sigma upper limit of L _ { x } \sim 8 \times 10 ^ { 41 } { erg s ^ { -1 } } in the 0.1-2 keV band .
However , we obtain a clear detection by ASCA yielding a luminosity in the 2-10 keV band of 2 \times 10 ^ { 42 } { erg s ^ { -1 } } .
Its X-ray spectrum is very hard , equivalent to a photon index of \Gamma = 1.0 \pm 0.35 .
We therefore , attempt to model the X-ray data with a ” scatterer ” model in which the intrinsic X-ray emission along our line of sight is obscured by an absorbing screen while some fraction , f , is scattered into our line of sight by an ionized medium ; this is the standard model for the X-ray emission in obscured ( but non Compton-thick ) Seyfert galaxies .
We obtain an absorbing column of 2 \times 10 ^ { 23 } cm ^ { -2 } for a power-law photon index of \Gamma = 1.9 , an order of magnitude above the column estimated on the basis of optical observations ; the percentage of the scattered emission is high ( \sim 20 per cent ) .
Alternatively , a model where most of the X-ray emission comes from reflection on a Compton thick torus ( N _ { H } > 10 ^ { 24 } cm ^ { -2 } ) can not be ruled out .
We do not detect an Fe line at 6.4 keV ; however , the upper limit ( 90 \% ) to the equivalent width of the 6.4 keV line is high ( \sim 3 keV ) .
All the above suggest that most of the X-ray emission originates in an highly obscured Seyfert-2 nucleus .