Dave Wittman and I are currently at the UC Berkeley remote observation room (pictured) on the Merging Cluster Collaboration's third Keck DEIMOS observing run.  The previous two runs returned about 2000 galaxy spectra of our merging cluster sample, and this run will produce about another 1000. 

We are using these spectra to gain insight into the dynamical history of the mergers as well as quantify their observed configurations (using the method I developed).  This is necessary information if we are to use these merging clusters to constrain the properties of dark matter.

This is the first time that we have not sent an observer to Hawaii and are using the UC Berkeley remote obs facility to control the telescope that is ~4000 km away.  Honestly this is not that different than when we observe from Hawaii  (I do miss the traditional pre-observing swim in the pacific though)  since you are sitting in a similar remote obs room at Waimea, essentially at the base of Mauna Kea (the telescope is on the summit).  The reason astronomers no longer go to the summit is that at 4200 m there is so little oxygen that it becomes hard to think clearly and altitude sickness is a possibility.

A third of the way through the night and it is shaping out to be another amazing night on Keck...

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. 

Copied from Chandra press release.

Using a combination of powerful observatories in space and on the ground, astronomers have observed a violent collision between two galaxy clusters in which so-called normal matter has been wrenched apart from dark matterthrough a violent collision between two galaxy clusters.

The newly discovered galaxy cluster is called DLSCL J0916.2+2951. It is similar to the Bullet Cluster, the first system in which the separation of dark and normal matter was observed, but with some important differences. The newly discovered system has been nicknamed the "Musket Ball Cluster" because the cluster collision is older and slower than the Bullet Cluster.