ORIGINS Guest Natalia Porqueres: Lifting weak lensing degeneracies with a field-based likelihood

Large Seminar Room: E.0.11 (MPA (Hybrid))

Large Seminar Room: E.0.11

MPA (Hybrid) Meeting ID: 501 799 782 Password: 704176

 Weak lensing is one of the most powerful probes of dark matter and dark energy. It will be the main science driver of the upcoming cosmological surveys, which promise to reach much greater precision than current observations and dramatically reduce the statistical uncertainties of the data. Traditionally, the analysis of weak lensing measurements is based on modelling some summaries of the data, such as correlation functions and power spectra. However, this approach is inevitably suboptimal and imposes approximations on the statistical and physical modelling. I will present a new method to analyse weak lensing data based on field-based statistics and a full physics model. This method, called BORG-WL, reconstructs the dark matter distribution and constrains the cosmological parameters. By analysing the data at the pixel level, BORG-WL lifts the weak lensing degeneracy, providing uncertainties on the cosmological parameters that are up to a factor 5 smaller than those from standard techniques on the same data. I will discuss the current status and ways to meet the challenges for the first real data application of BORG-WL.

Meeting ID: 501 799 782
Password: 704176

Natalia Porqueres, Imperial College London, is an ORIGINS guest (hosts Daniel Gruen, Torsten Enßlin, Fabian Schmidt) visiting us for the month of May who will also be attending the MIAPP workshop "Advances in Cosmology through Numerical Simulation."