We present an analysis of 39 X–ray luminous early–type galaxies observed with the ROSAT PSPC .
Using multi–component spectral and spatial fits to these data we have measured halo abundance , temperature , luminosity and surface brightness profile .
We compare these measurements to similar results from galaxy groups and clusters , fitting a number of relations commonly used in the study of these larger objects .
In particular , we find that the \sigma : T _ { \mathrm { X } } relation for our sample is similar to that reported for clusters , consistent with \beta _ { spec } = 1 , and that the L _ { \mathrm { X } } : T _ { \mathrm { X } } relation has a steep slope ( gradient 4.8 \pm 0.7 ) comparable with that found for galaxy groups .
Assuming isothermality , we construct 3-dimensional models of our galaxies , allowing us to measure gas entropy .
We find no correlation between gas entropy and system mass , but do find a trend for low temperature systems to have reduced gas fractions .
We conclude that the galaxies in our sample are likely to have developed their halos through galaxy winds , influenced by their surrounding environment .