Silvan Fischbacher

Research area

I am a PhD student in the Cosmology Research Group of Prof. Refregier since November 2021. I am a member of the Dark Energy Survey (DES) and the Vera Rubin Observatory's Legacy Survey of Space and Time (LSST). My focus is on cosmic shear analysis, where I work mainly on systematics such as intrinsic alignment and photometric redshift uncertainty, and on a novel forward modelling approach called Monte Carlo Control Loops (MCCL).

In a first project (see JCAP01(2023)033call_made) we investigated how systematic redshift errors are coupled to intrinsic alignment modelling. As one of the main results, we calculated the redshift requirements for current and upcoming surveys for different intrinsic alignment models.

I am currently working on improving and extending the galaxy population model inference within the MCCL framework. We constrain a parametric galaxy population model to produce realistic image simulations. Improving the speed of this step is essential. One approach to speed up this part is to use an emulator for the transfer function from simulated galaxies to detected galaxies. I am also involved in several extensions of the model: improving the galaxy sampling using stellar population synthesis, extending the image simulation to more data sets (after DES and HSC, e.g. KiDS-VIKING), and including realistic clustering in the simulations.