To test the cooling flow model of early-type galaxies , we obtained a complete magnitude-limited sample of 34 early-type galaxies , observed with the PSPC and HRI on ROSAT .
The X-ray to optical distribution of galaxies implies a lower envelope that is consistent with the stellar emission inferred from Cen A .
When this stellar component is removed , the gaseous emission is related to the optical luminosity by L _ { X } \propto L _ { B } ^ { m } , where m = 3.0-3.5 , significantly steeper than the standard theory ( m = 1.7 ) .
The dispersion about the correlation is large , with a full range of 30-100 in L _ { X } for fixed L _ { B } .
The X-ray temperature is related to the velocity dispersion temperature as T _ { X } \propto T _ { \sigma } ^ { n } , where n = 1.43 \pm 0.21 , although for several galaxies , T _ { X } is about twice T _ { \sigma } .
The excessively hot galaxies are generally the most luminous and are associated with the richest environments .
We suggest a model whereby environment influences the X-ray behavior of these galaxies : early-type galaxies attempt to drive partial or total galactic winds , which can be stifled by the pressure of their environment .
Stifled winds should lead to hotter and higher luminosity systems , which would occur most commonly in the richest environments , as observed .