Sharp Images, New Features: Chandra Examines the NGC 741 Group

Most galaxies are found in groups, which shape the surroundings in which their member galaxies evolve and influence the development of larger structures through their continuing infall into clusters. The high angular resolution of Chandra has shown us a rich new view of phenomena in groups, as it has in clusters. We illustrate this point here with results on the NGC 741 group, which is dominated by a close pair of ellipticals at the center and shows a bright narrow-angle tail radio source with a complex, sharply-bent morphology. Although the X-ray emission is centered on NGC 741 and shows a modest cooling core, both central galaxies are active in X-rays and radio. Very narrow (<1 kpc width) filaments visible in X-rays, one of which joins NGC 741 and NGC 742, are a remarkable feature of this system revealed by Chandra; such filaments suggest the presence of a confinement mechanism, as they would otherwise be expected to dissipate about an order of magnitude faster than the encounter timescale of the galaxies.