With the fast development of high-precision large photometric surveys, weak lensing (WL) effects have become one of the major probes in cosmology. While the two-point shear correlations are the most extensively employed analyses, other statistics are desired because of the non-Gaussian nature of cosmic structures. In this presentation, I will introduce a new analysis method, namely WL peak steepness statistics, inspired by the machine learning studies from others. For high peaks, their steepness is sensitive to the density profile of massive halos that encodes the effects from baryonic feedback and the dark matter properties. Thus by combining the peak height and steepness statistics, we can potentially detect and constrain non-cosmological effects simultaneously with cosmological parameters.
Euclid and the China Space Station Survey Telescope (CSST) are both space-based Stage IV surveys aiming for high precision cosmological studies. The two missions cover nearly the same survey areas and have similar spatial resolutions. However, the wave bands are very complementary to each other. In this talk, I will also present our studies exploring the potential scientific synergies of the two missions.
