1610.00840
Statistical connection of peak counts to power spectrum and moments in weak lensing field
Shirasaki
The number density of local maxima of weak lensing field, referred to as weak-lensing peak counts, can be used as a cosmological probe. However, its relevant cosmo information is still unclear. Study the relationship between the peak counts and other statistics in weak lensing field by using 1000 ray-tracing sims. Construct a local transformation of lensing field K to a new Gaussian field y, named local-Gaussianized transformation. Calibrate the transformation with numerical sims so that the one-point distribution and the power spectrum of K can be reproduced from a single Gaussian field y and monotonic relation between y and K. Therefore, the correct information of 2pt clustering and any order of moments in WL field should be preserved under local-Gaussianized transformation. Then examine if local-Gaussianized transformation can predict WL peak counts in sims. The local-Gaussianized transformation underestimates the simulated peak counts with a level of ~20-30% over a wide range of peak heights. Local-Gaussianized transformation can predict the WL peak counts with a ~10% accuracy in the presence of shape noise. The analyses suggest that the cosmo information beyond power spectrum and its moments would be necessary to predict the WL peak counts with a percent-level accuracy, which is an expected statistical uncertainty in upcoming wide-field galaxy surveys.
No comments:
Post a Comment