Session J4: Cosmology with the Dark Energy Survey

Supernovae from the Dark Energy Survey

The nature of dark energy is one of the greatest unsolved problems in physics today. Its existence was inferred from observations of exploding stars known as Type Ia supernovae (SNe Ia). These SNe Ia are standardizable candles that are excellent cosmological tools for probing dark energy through the distance-redshift relation. The Dark Energy Survey (DES) Supernova Program is repeatedly observing 30 square degrees within the full 5000-square-degree DES footprint and has discovered thousands of SNe Ia, in addition to many other types of SNe. DES has recently completed Year 3 of observations, with at least two more years still to go. In this talk, I will highlight the papers that have been published by the DES SN Program as well the ongoing analyses and projects within the group. I will introduce frameworks being developed for cosmological inference using Bayesian hierarchical regression models and discuss the steps needed for this. These include the transient detection pipeline, photometric calibration, host galaxy identification, follow-up spectroscopy of SNe and host galaxies, and SN photometric classification. I will also discuss DES discoveries of several superluminous SNe.   

Weak lensing in the Dark Energy Survey

I will present the current status of weak lensing results from the Dark Energy Survey (DES). DES will survey 5000 square degrees in five photometric bands (grizY), and has already provided a competitive weak lensing catalog from Science Verification data covering just 3\% of the final survey footprint. I will summarize the status of shear catalog production using observations from the first year of the survey and discuss recent weak lensing science results from DES. Finally, I will report on the outlook for future cosmological analyses in DES including the two-point cosmic shear correlation function and discuss challenges that DES and future surveys will face in achieving a control of systematics that allows us to take full advantage of the available statistical power of our shear catalogs.   

Probing the large scale structure with the Dark Energy Survey

I will present the latest cosmological results from the Dark Energy Survey (DES), a 5000 square degree optical galaxy survey in the Southern Hemisphere started in 2012. I will focus on the constraints on Baryon Acoustic Oscillations and other cosmological parameters obtained with galaxy clustering measurements from the first years of DES data. I will highlight the various tests and methods that make these results not only precise but also robust against observational systematics and modeling uncertainties. Finally, I will describe the future phases of the survey, the expected increase in constraining power, and the challenges that need to be addressed to fully exploit the data from surveys such as DES and LSST.