Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - COSMIC LENS (Delivering on the Promise of Measuring Dark Energy from Cosmic Lensing)

Teaser

Our goal is to measure the density and clumpiness of the dark matter, and to use this to measure the equation of state of dark energy. This is important to society because of mankind’s innate curiosity about the contents of the Universe, and our desire to understand the...

Summary

Our goal is to measure the density and clumpiness of the dark matter, and to use this to measure the equation of state of dark energy.
This is important to society because of mankind’s innate curiosity about the contents of the Universe, and our desire to understand the missing 95% of the Universe.
The overall objectives are to use the data from the Dark Energy Survey and other probes to put the definitive constraints on dark energy for the present decade, and to use this to inform future cosmological constraints from surveys such as the Large Synoptic Survey Telescope, which will dominate the cosmological landscape of the decade to come.

Work performed

We have played a major role in developing techniques for the analysis of cosmic shear data, and understanding its role in the context of the wider cosmological framework. In particular we have invested the majority of our effort so far in capitalizing on the data taken in the largest ongoing cosmological survey of the current decade, the Dark Energy Survey (DES). Our group led one of the two shear pipelines used for the cosmic shear analysis (im3shape) in the main results of the first year of DES operations (WP1) (Samuroff, Bridle et al; Zuntz et al). Furthermore we led work that demonstrated the major role of galaxy clustering in mitigating photometric redshift uncertainties (Samuroff, Troxel, Bridle et al) and led the main observational paper that allowed this to be implemented in the DES first year results (Elvin-Poole et al). We therefore played a crucial role in the cosmological constraints from cosmic shear (Troxel et al) and from DES (Abbott et al) from the first year of DES operations. We have since carried out a number of studies to develop new methods (Tessore; Tessore & Bridle) and understand the wider cosmological context including constraints on massive neutrinos (multiple papers by di Valentino; Bridle, Elvin-Poole et al). However, the majority of our time over the past year has been invested in playing leading roles in the preparation of the extended results from DES Year 1 (di Valentino) and in the results from the data from DES years 1 to 3.

Final results

The DES Year 1 papers took the field beyond the state of the art in both methodology and cosmological constraining power, and this will be significantly extended by the DES data from years 1-3 (ongoing analysis) and DES years 1-5 (expected by the end of the project).