Next Section: Introduction

HI in Shell Galaxies and other Merger Remnants

David Malin
Anglo-Australian Observatory
P.O. Box 296, Epping NSW 2121 Australia
dfm@aaoepp.aao.gov.au
Brian Hadley
Royal Observatory, Edinburgh
Blackford Hill Edinburgh, EH9 3HJ, UK

Abstract:

The few elliptical galaxies with detected HI almost always seem to have optical peculiarities as well, though these are often well hidden and require special image enhancement techniques to reveal them. In this paper we show several deep images of ellipticals with optical shells which are associated with HI, and suggest that mergers, or at least encounters with gas-rich galaxies are responsible. We also show some disk galaxies with unusual faint extensions, some of them the kinds of interactions that may result in HI in ellipticals. These illustrations are drawn from an atlas of low surface brightness images of bright galaxies currently in preparation.

Keywords:

galaxies:elliptical and lenticular - galaxies:interactions - galaxies:structure - galaxies:halos

© Copyright Astronomical Society of Australia 1997