Hα images of nearby galaxy groups NGC193 and NGC940

A significant fraction of the baryons in galaxy groups and clusters is not locked up in stars and the interstellar medium (ISM), but exists in the form of extended multi-phase gas. The advantage of nearby galaxy groups is that this multi-phase gas can be studied via X-ray observations probing the hot gas (≈ 107K), and optical emission line observations (e.g. Hα filaments) probing the ionised warm gas. Another advantage is that the effects of the galaxies’ heating process of their surrounding gas (e.g. feedback from AGN) are more visible due to lower density and mass, and because groups contain fewer galaxies than rich clusters. Interaction between the different phases is important for galaxy formation and evolution due to the fact that at least 50% of galaxies can be found in groups and clusters. The Complete Local-Volume Groups Sample (CLoGS) is an optically selected sample of 53 groups within 80 Mpc of which the X-ray observations (Chandra / XMM-Newton) have already been done and can be used to infer important physical properties, such as gas temperature and X-ray luminosity. In this project the Hα images, observed using the WIYN 0.9m telescope on Kitt Peak, are analysed with the aim to compare the Hα filaments to the X-ray emission images. Here we present preliminary results and a multi-wavelength comparison for two rich galaxy groups: NGC193 and NGC940. Despite their differences, we detect Hα in the central members of both galaxy groups.