M. Wood-Vassey: The ESSENCE of dark energy
There are different approaches to measure w (Baryon accoustics, Galaxy clusters, Supernova Luminosity distances and an on-the-spot addition of weak lensing (was fun watching the speaker change his slide...). For supernova distancies the systematics have to be understood, and get the statistics right (finding the correct confidence limits on w).
M.W. then made some general remarks that were quite funny, and I also wholeheartedly agree on most of them.
Thoughts for observers: Design your experiment, design your analysis, test your analys, ignore the theorist, get a pet theorist.
Thoughts on theorists: Too many theories (quintessence as an example), far too many models (can fit anything)-> All M.W. wants is a well-motivated theory.
The ESSENCE survey is a 6year project on the CTIO in Chile. Data released immediately after reduction, using 2 filters. Getting SNe at z~0.7. They are cross-checking the results using the SNLS SALT. They get w=-0.88 (0.12), but it's still consistent with w=-1 (error margin only 68% confidence). Essence is using a similar approach as the the project I'm working on for subtracting images and detecting SNe.