Speaker
Description
Galaxy groups are particularly interesting in the hierarchical structure of the universe as they lie between the relatively low-density structure of the field and the high-density structure of clusters. As such they reveal how galactic interactions and rising density impact galaxies as they move from the blue cloud to the red sequence. The MeerChoirs groups are late-type dominated, gas-rich and are believed to be in the early stages of their assembly. The group focused on in this study, HIPASS J1059-09, features a central pair of strongly interacting galaxies accompanied by a tidal dwarf alongside various other spiral and dwarf galaxies. This study utilizes the sensitive and highly resolved data from MeerKAT to study the effect of group environments on galaxy HI content and how this is connected to star formation and other galaxy properties. The MeerKAT observations have revealed faint HI gas not seen in previous studies including an HI bridge connecting a third member to the central interaction, and faint tails of anomalous gas extending outward from the central pair, as well as additional member galaxies outside of the original field of view. We investigate the impact of the ongoing interaction on the HI profile of the central pair and characterise several known and unknown galaxies. We extract the kinematic and geometric properties of the interacting galaxies and several other group members through 3D tilted ring modelling and identify anomalous gas within the central interaction using Gaussian decomposition. We separate the anomalous gas from the disk and into leading, lagging, and Non-Disk Anomalous Gas components. We relate the anomalous gas to the star formation rates of group members through kinematics and evidence from the literature. This study has led to a better understanding of the dynamical history of groups and the effect of the environment on galaxy evolution.
| Stream | Science |
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