Evolution of Starburst Galaxies in the Illustris Simulation

TL;DR

This study uses the Illustris simulation to analyze how different mechanisms, including mergers and non-merging interactions, trigger starburst events in galaxies, revealing environmental influences and properties of starburst populations.

Contribution

It provides new insights into the roles of merging and non-merging interactions in triggering starbursts using detailed simulation data.

Findings

55% of starbursts not caused by recent mergers

Pre-merger starbursts are in higher density environments

Both types produce nuclear starbursts of similar strength

Abstract

There is a consensus in the literature that starburst galaxies are triggered by inter- action 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 effect starburst events. We examine 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 AGN 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 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 starburst 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.