|
---|
Research: Interactions and Mergers |
|
Tidal interactions and mergers are believed to play a key role in the evolution of galaxies. Such phenomena can not only enhance the activity in and around the nuclear region (star-formation, AGN) but are also believed to irreversibly alter the morphological appearance of the participant galaxies. Of particular significance among galaxy interactions are mergers between spiral galaxies. These are thought to be responsible not only for the spectacular starbursts revealed by IRAS but also and most importantly for the formation of elliptical galaxies. Indeed, this formation scenario, called the ``merger hypothesis'', has gained significant impetus over the past few years by both observational and theoretical studies. However, despite the extensive work on disc galaxy mergers, little is known about the evolution of these systems during the various stages of the interaction (pre-mergers, nuclear coalescence, post-mergers). Moreover, it is not yet clear how the properties of post-mergers compare with those of ``normal'' (old/relaxed) ellipticals. Such a study has the potential to address the following points:
To study disc galaxy mergers a sample of merging systems at different stages during the interaction has been compiled. This sample is then ordered in chronological order, starting from early interacting spirals, systems close to nuclear coalescence and finally post-mergers spanning a wide range of ages after the merger event. The evolution of galaxy properties (e.g. cold gas content, radio-emission, dust proprties; Georgakakis et al. 2000; 2001; Xilouris et al. 2004) along this sequence is then studied to address the points above. |
---|