Environment from Cross-correlations: Mapping Effect To the Cause
Date Submitted
2017-04-13 11:22:05
GalEnv
Egidijus Kukstas
Liverpool John Moores University
Poster
Ian McCarthy, Andreea Font
Galaxies evolve differently depending on the environment they are in. There is significant evidence showing that galaxies in relatively dense parts of the Universe, such as groups and clusters, tend to be red ellipticals with suppressed star formation rates. Which exact processes, gravitational (tidal) or hydrodynamic (ram pressure stripping, harassment etc.) in nature, are dominant and the timescales on which they act are still unknown.
Existing studies have relied on investigating the evolution of optical galaxy properties without the benefit of knowing what the local dark matter (DM) and hot gas (HG) conditions are. This is largely due to the difficulty in obtaining direct observations, resulting in the inability to determine the dominant process, especially when it is likely that several are acting at the same time.
However, there has been a revolution recently in our ability to directly constrain the local DM and HG properties via large scale gravitational lensing, thermal Sunyaev-Zel’dovich, and X-ray surveys. The observational limits can be overcome by considering a large statistical sample, treating groups and clusters statistically rather than by looking at them individually. By cross-correlating galaxy properties with these new data sets, we can directly map the response of galaxy properties to
these quantities and try to determine the dominant environmental processes at play. This will be the very first time this has been done!
In this talk I will expand on the methods employed and present some of the early results in this study.