We reanalyzed the ROSAT/HRI observation of MS1054-03 , optimizing the channel HRI selection and including a new exposure of 68 ksec .
From a wavelet analysis of the HRI image we identify the main cluster component and find evidence for substructure in the west , which might either be a group of galaxies falling onto the cluster or a foreground source .

Our 1–D and 2–D analysis of the data show that the cluster can be fitted well by a classical \beta –model centered only 20 \arcsec away from the central cD galaxy .
The core radius and \beta values derived from the spherical model ( \beta = 0.96 _ { -0.22 } ^ { +0.48 } ) and the elliptical model ( \beta = 0.73 \pm 0.18 ) are consistent .

We derived the gas mass and total mass of the cluster from the \beta –model fit and the previously published ASCA temperature ( 12.3 ^ { +3.1 } _ { -2.2 } { keV } ) .
The gas mass fraction at the virial radius is \hbox { $f _ { gas } $ } = ( 14 \small { [ -3 , +2.5 ] } \pm 3 ) \% for \Omega _ { 0 } = 1 , where the errors in brackets come from the uncertainty on the temperature and the remaining errors from the HRI imaging data .
The gas mass fraction computed for the best fit ASCA temperature is significantly lower than found for nearby hot clusters , \hbox { $f _ { gas } $ } = 20.1 \pm 1.6 \% .
This local value can be matched if the actual virial temperature of MS1054-032 were close to the lower ASCA limit ( \sim 10 ~ { } { keV } ) with an even lower value of 8 ~ { } { keV } giving the best agreement .
Such a bias between the virial and measured temperature could be due to the presence of shock waves in the intracluster medium stemming from recent mergers .
Another possibility , that reconciles a high temperature with the local gas mass fraction , is the existence of a non zero cosmological constant .