Speaker
Description
Friends-of-friends is a simple yet powerful algorithm for identifying groups of galaxies that likely share a common dark matter halo. However, an evolutionary perspective on gas in galaxy groups would lead us to prefer an algorithm that can identify groups in an early stage of formation that may not yet share a common halo. To address this, we are developing alternative definitions of galaxy groups that are based on physical considerations, such as gravitational attraction or virialization state. In particular, we are testing alternative group definitions against conventional techniques using the complete, volume-limited REsolved Spectroscopy of a Local VolumE (RESOLVE) survey. RESOLVE has an existing group catalog based on friends-of-friends, spans a large volume containing groups at many stages of evolution, and offers a deep HI census reaching into the dwarf galaxy regime. We are also working to extend our tests to a new volume-limited sub-survey within the Looking At the Distant Universe with the MeerKAT Array (LADUMA) survey, enabling direct evolutionary comparison across redshifts.
| Wish list question? | 12. How can a z ~ 0 HI survey usefully inform the analysis of a z ~ 1 HI survey – and perhaps vice versa? |
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