GALAXY EVOLUTION IN THE FIELD: DO SHELL GALAXIES HAVE DIFFUSE X-RAY EMISSIONquestionMark

Shell galaxies represent the ideal class of objects to investigate galaxyevolution in the field. Although their origin has been explained in theframework of different scenarios (weak interaction, accretion, major mergingevents), the environment in which shell galaxies evolve is predicted to be oflow density: in clusters, continuous harassment would destroy shells,otherwise longlasting features able to persist for several Gyrs. In the Xrayband, we can test whether these galaxies, now in very low density environments,retain information about the richer environment in which they evolved in theform of a hot IGM. We therefore propose to observe 4 shell galaxies for which wehave direct evidence of ongoing interaction and/or recent merging events. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]