with XMM-Newton?

Received; accepted Context. The environment appears to have a strong influence on fundamental properties of galaxies, modifying their morphology and their star formation histories. Similarly, galaxies play a role in determining the properties of the hot intergalactic medium in groups, heating and enriching it through a variety of mechanisms. NGC 5238 and NGC 4756 are the brightest unperturbed elliptical galaxies in their respective loose groups, but analysis of their environment suggest that they might be at different evolutionary stages. Aims. In the present study we aim at characterizing the properties of the hot gas in the halos of the brightest members and in the environment. In NGC 4756 we are also interested in the properties of a substructure identified to the SW and the region connecting the two structures, to search for a physical connection between the two. However, we have to take into account the fact that the group is projected against the bright, X-ray emitting cluster A1361, which heavily contaminates and confuses the emission from the foreground structure. Methods. We present XMM-Newton observations of the groups and the careful analysis to separate different components. We examine the X-ray morphology, hot gas distribution and spectral characteristics of NGC 4756 and NGC 5328 and their companion galaxies. To better characterize the ambient, we also present a re-evaluation of the dynamical properties of the systems. SPH simulations are used to interpret the results