Photometric study of the IC 65 group of galaxies

Abstract

We carry out a photometric study of a poor group of late-type galaxies around IC 65, with the aim: (a) to search for new dwarf members and to measure their photometric characteristics; (b) to search for possible effects of mutual interactions on the morphology and star-formation characteristics of luminous and faint group members; (c) to evaluate the evolutionary status of this particular group. We make use of our BRI CCD observations, DPOSS blue and red frames, and the 2MASS JHK frames. In addition, we use the HI imaging data, the far-infrared and radio data from the literature. Search for dwarf galaxies is made using the SExtractor software. Detailed surface photometry is performed with the MIDAS package. Four LSB galaxies were classified as probable dwarf members of the group and the BRI physical and model parameters were derived for the first time for all true and probable group members. Newly found dIrr galaxies around the IC 65 contain a number of H II regions, which show a range of ages and propagating star-formation. Mildly disturbed gaseous and/or stellar morphology is found in several group members. Various structural, dynamical, and star-forming characteristics let us conclude that the IC 65 group is a typical poor assembly of late-type galaxies at an early stage of its dynamical evolution with some evidence of intragroup (tidal) interactions.