With the SDSS Supernova Survey now over, Betoule et al. (2014) today provides one of the “most stringent constraints to date on the nature of dark energy” using a combination of the SDSS and SNLS supernova surveys; only a 5.7% error on w, the equation-of-state of Dark Energy (see above or Fig 15 in paper). The paper uses the full 3-year SDSS SN sample and provides a comprehensive re-examination of both the SDSS and SNLS photometric (cross-)calibration, which is the main systematic uncertainty in these present surveys.
This re-analysis shows that such accuracy is achievable from SN surveys if modern photometric techniques are employed, especially from the start. The analysis also re-discovers the clear correlation between host galaxy properties (stellar mass herein) and the residuals on the Hubble Diagram, re-confirming the importance of this correlation that has been studied in detail at the ICG (Lampeitl et al. 2010, D’Andrea et al. 2011, Johansson et al. 2013).
“Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova surveys” by Betoule et al. (including present and past ICG scientists Bruce Bassett, Chris D’Andrea, Heather Campbell, Bob Nichol, Mat Smith), submitted to A&A