working on fundamental physics at Heidelberg University, Zentrum für Astronomie. my scientific interests include cosmology, the formation and evolution of the cosmic large-scale structure, gravitational lensing and CMB-anisotropies as a probe of fundamental physics, and cosmostatistics

recent projects

3D reconstructions


The phase-space of the cosmic large-scale structure is only partially accessible to observations. The resolution of structures along the line of sight is particularly difficult in weak lensing observations, but also in galaxy surveys one deals with rather large radial uncertainties. For that purpose, we employ 3d-decompositions and investigate the observability of 3d-Fourier modes, in weak lensing and in cross-correlation with other tracers.

intrinsic alignments


Weak lensing operates under the assumption of intrinsically uncorrelated galaxy shapes, which might not be true because galaxies experience correlated tidal gravitational fields and share a similar angular momentum generation. We have worked on tidal interaction models for galaxies to derive ellipticity correlations for investigating their contaminating effect in weak lensing parameter inference.

cosmic inflation


cosmic inflation is an early phase of accelerated expansion that solves the flatness-problem in FLRW-cosmologies and is a mechanism for introducing fluctuations in the distribution of matter. Of particular interest to us are inflationary non-Gaussianities and their measurement in future large-scale structure surveys.

statistical inference


Modern cosmology is a statistical science and we are interested in questions related to the information content of large-scale structure surveys, in particular in the nonlinear regime, selection of models and the effect of systematical errors on the parameter estimation and model selection process.

constructive cosmology


Constructive gravity asserts that there is a clear path of constructing a gravitational interaction for particles that is determined completely by their non-gravitational properties. Our group works in cooperation with F.P. Schuller and M.C. Werner on cosmological tests of constructive gravity.



The European Euclid mission is a space-based large-scale structure survey, where I am involved in the weak lensing programme.

weak gravitational lensing


Weak lensing refers to the weak distortion of the light bundles reaching us from distant galaxies caused by tidal gravitational fields in the cosmic large-scale structure. Weak lensing is an excellent tool for investigating gravity on large scales, and we have worked on tomographic methods, cross-correlations and higher-order statistics of the weak lensing signal, as well as effects gravitational light deflection at second order.