Evolution of starburst galaxies in the Illustris simulation

There is a consensus in the literature that starburst galaxies are triggered by interaction events. However, it remains an open question as to what extent both merging and non-merging interactions have in triggering starbursts. In this study, we make use of the Illustris simulation to test how different triggering mechanisms can affect starburst events. We examine the star formation rate, colour, and environment of starburst galaxies to determine if this could be why we witness a bimodality in post-starburst populations within observational studies. Further, we briefly test the extent of quenching due to active galactic nuclei feedback. From Illustris, we select 196 starburst galaxies at z = 0.15 and split them into post-merger and pre-merger/harassment-driven starburst samples. We find that 55 % of this sample have not undergone a merger in the past 2 Gyr. Both of our samples are located in low-density environments within the filament regions of the cosmic web; however, we find that pre-merger/harassment-driven starbursts are in higher-density environments than post-merger-driven starbursts. We also find that pre-merger/harassment starbursts are redder than post-merger starbursts; this could be driven by environmental effects. Both, however, produce nuclear starbursts of comparable strengths.