Speaker
Description
Galaxy cluster mergers are rich sources of information to test both cluster astrophysics and cosmology. However, cluster mergers produce complex projected signals that are difficult to interpret from individual observational probes. Multi-probe constraints on both the gas and dark matter cluster components are necessary to infer merger parameters that are otherwise degenerate. We have developed ICM-SHOX (Improved Constraints on Mergers with SZ, Hydrodynamical simulations, Optical, and X-ray), a systematic framework to jointly infer cluster merger parameters quantitatively via a pipeline that directly compares a novel combination of multi-probe observables to mock observables derived from hydrodynamical simulations. In our first application of the ICM-SHOX pipeline to the MACS J0018.5+1626 system, we discovered a velocity-space decoupling of the gas and dark matter distributions, which we attribute to the different collisional properties of the two components. We are now obtaining new and deeper observations of MACS J0018.5+1626 to confirm the possible detection of a rare equatorial shock as a result of the merger. In another system, MACS J2129.4-0741, we find hints of a Bullet Cluster-like morphology in the X-ray data, which strongly suggests a plane-of-sky merger, along with high line of sight velocities in both the gas and dark matter, which strongly suggests a merger in that direction. We do not yet have a complete understanding of how to reconcile these observables. In this talk, I will provide an overview of these exciting cluster mergers and the status of our updated ICM-SHOX pipeline.
| Would you be interested in presenting a poster if the conference is oversubcribed? | Yes |
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