Gone with the wind: signatures of gas removal in environmentally perturbed galaxies
thesisposted on 28.03.2022, 22:16 by Taylah Kate Beard
The knowledge of a galaxy's star formation history, both globally and in a resolved manner, provide key pieces of information for understanding galaxy formation and evolution. The KOALA integral field unit (IFU) and the AAOmega spectrograph on the Anglo-Australian Telescope (AAT) were used to follow up two galaxies within Abell 119 (z = 0:0442) which were previously investigated within the SAMI Galaxy Survey. The KOALA IFU provides a wider field of view of these galaxies when compared with the SAMI observations, allowing the search for signatures of environmental interactions which occur at large galactocentric distances, such as ionised tails of stripped gas. In both galaxies, 9011900084 and 9011900166, we observed one-sided extraplanar tails of ionised gas extending respectively ~ 16:1 kpc and ~ 6:1 kpc in projection off their stellar disk. The orientation of these tails in relation to the cluster centre inferred the galaxies direction of motion as towards apocentre from observed post-pericentre and pericentre positions, respectively. Line ratios measured in the tails indicate ionisation through non-SF LINER sources, unlike that observed in jellyfish galaxies. This thesis therefore supports a scenario where ram pressure stripping (RPS) is removing gas from galaxies as they traverse the cluster, leading to the ongoing quenching of star formation.