Key points are not available for this paper at this time.
Galaxy interactions/mergers have been shown to dominate the population of IR-luminous galaxies (L IR 10 11.6 L ) in the local universe (z 0.25). Recent studies based on the relation between galaxies' star formation rates and stellar mass (the SFR-M * relation or the "galaxy main sequence") have suggested that galaxy interaction/mergers may only become significant when galaxies fall well above the galaxy main sequence. Since the typical SFR at a given M * increases with redshift, the existence of the galaxy main sequence implies that massive, IR-luminous galaxies at high z may not necessarily be driven by galaxy interactions. We examine the role of galaxy interactions in the SFR-M * relation by carrying out a morphological analysis of 2084 Herschel-selected galaxies at 0.2 10 11.5 L , 50% of the objects show evident features of strongly interacting/merger systems, where this percentage is similar to the studies of local IR-luminous galaxies. The fraction of interacting/ merger systems also systematically increases with the deviation from the SFR-M * relation, supporting the view that galaxies falling above the main sequence are more dominated by mergers than the main-sequence galaxies. Meanwhile, we find that 18% of massive IR-luminous "main-sequence galaxies" are classified as interacting systems, where this population may not evolve through the evolutionary track predicted by a simple gas exhaustion model.
Hung et al. (Tue,) studied this question.