News‎ > ‎

The Merging Cluster Collaboration wins funding by UC-HiPACC

posted Sep 17, 2012, 4:15 PM by William Dawson   [ updated Sep 17, 2012, 4:16 PM ]
We were just awarded a grant from UC-HiPACC to establish a UC Davis - UC Irvine collaboration to study merging clusters, with the directive of determining the nature of dark matter. Dark Matter is one of the great outstanding mysteries.  Although still in its infancy, the study of merging galaxy clusters has been shown to be one of the best means of determining the nature of dark matter.  However to realize this potential requires a concerted effort on the part of astronomers and computational theorist, due to necessity to compare simulations and observations of real systems.  

The UC Davis group members (Maruša BradačWill DawsonJames Jee, and Dave Wittman) have led the observational investigation of four of the 10 confirmed dissociative mergers (see the figure below) and have extensive experience (as well as the data) for all observational aspects of merging clusters.   The UC Irvine group (James BullockManoj KaplinghatAnnika Peter, and Miguel Rochahas experience in incorporating dark-matter interactions (see SIDM in the figure below) using a modified version of the GADGET-2 N-body simulation code.   The UC Irvine group also has access to NASA's Pleiades computing cluster and the UC Irvine Greenplanet computing cluster to run and analyze the simulations.
The four merging clusters for which the UC Davis group members have led the observation and analysis of (Bradac et al. 2006; Jee et al. 2012; Bradac et al. 2008; Dawson et al. 2012). These dissociative mergers represent a diverse sampling of masses, collision velocities, and observed times since collisions. The fifth cluster on the right is from a simulation of two SIDM halo’s post collision (Rocha et al. 2012, in prep).
This collaboration can trace its foundation back to a visit from James Bullock to UC Davis on January 2012.  He came to give a talk on his group's research of simulating self-interacting dark matter in galaxies and clusters.  I told him about the recent constraints on self-interacting dark matter made with the Musket Ball Cluster, and some of the promising new findings (coming soon).  It was a fruitful discussion that lead to the decision that we should simulate the Musket Ball.  Later it became apparent that the idea was too good to limit to ourselves and thus the Merging Cluster Collaboration was born.

The grant is for $20,000 ($10,000 pending) over two years and will support an annual all-hands week-long meeting, followed by quarterly week long exchanges of one graduate student or post doc.  These regular exchanges will be the lifeblood of this group and are vital to its success.  With its success this group will become self-sustaining and make UC the world leader in this young field that holds so much potential.