Speaker
Description
Galaxy clusters are powerful probes used to constrain the cosmology of our universe. However, they are peppered with several systematic biases such as projection effects. Of them, the orientation of triaxial clusters with respect to the line-of-sight is expected to be one of the prime sources of scatter and potential bias in optical observables (i.e., richness and weak-lensing signal) of galaxy clusters. We used the observed shape of the central, Brightest Cluster Galaxy (BCG) as a proxy for the orientation along the line-of-sight for clusters selected via the Sunyaev-Zel’dovich (SZ) effect from the South Pole Telescope (SPT) and Atacama Cosmology Telescope (ACT) surveys, matched to optically selected clusters from the Dark Energy Survey Year 3 (DES). In this talk, I will show that there is not only a significant correlation between the BCG shape and the observed weak lensing signal but also a non-trivial difference from the expected effect of triaxiality from simulations. We speculate that the intrinsic shape of the BCG reflects not just the orientation angle, but also the assembly history of the cluster. I will discuss the implications and results of testing this hypothesis.
| Would you be interested in presenting a poster if the conference is oversubcribed? | Yes |
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