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...

It's official. As of August 30th 2013 I am now Dr. Dawson.  

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. 

This has been a great week so far!  Five days ago I found out that our Keck proposal was accepted and that I would be headed to Hawaii in January.  Then today I found out that our Westerbork Synthesis Radio Telescope (WSRT) proposal was accepted. 

I have been leading the effort to study in detail a newly discovered dissociative galaxy cluster merger (DLSCL J0916.2+2951* a.k.a the Musket Ball Cluster), were the collisionless dark matter (blue, in the figure below) and galaxies have become separated from the collisional cluster gas (red, in the figure below). To date only 5 dissociative mergers have been confirmed, the most famous being the Bullet Cluster.   These dissections of the cosmos are proving to be some of the best laboratories for studying dark matter.

*This unattractive name refers to the fact that it was discovered in the Deep Lens Survey, is a cluster, and where it is located. Our team affectionately calls it the Musket Ball Cluster since it is similar to the Bullet Cluster yet older and slower.

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.

Copied from Chandra::Chronicles

Astronomy can generate a large amount of attention from the public, but the number of working astronomers is smaller than the number of researchers in many other academic fields. So, when people get over their surprise at meeting a real astronomer, they often ask "How did you end up working in this field?". There are many different answers, but an interesting one is provided here by Will Dawson from the University of California, Davis, who kindly explains his career change from engineering to astronomy. We were very satisfied to hear that part of his motivation for this big change came from the publicity generated by the Bullet Cluster in 2006.

Will is the first author of a recent paper describing the discovery of the Musket Ball Cluster.