2016/10/31 by Masato Shirasaki
Mathematics · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics #Field (mathematics) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Mathematics #Noise (video) #Physics #Redshift #Spectral density #Statistical physics #Statistics #Transformation (genetics) #Weak gravitational lensing #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stw2950
10 pages, 5 figures, accepted for publication in MNRAS
openalex created_date 2016/10/14 · openalex publication_date 2016/11/16 · arxiv created 2016/11/28 · arxiv updated 2016/12/21 · openalex updated_date 2026/08/05
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 cosmological information is still unclear. We study the relationship between the peak counts and other statistics in weak-lensing field by using 1000 ray-tracing simulations. We construct a local transformation of lensing field |\cal K| to a new Gaussian field y, named local-Gaussianized transformation. We calibrate the transformation with numerical simulations so that the one-point distribution and the power spectrum of |\cal K| can be reproduced from a single Gaussian field y and monotonic relation between y and |\cal K|. Therefore, the correct information of two-point clustering and any order of moments in weak-lensing field should be preserved under local-Gaussianized transformation. We then examine if local-Gaussianized transformation can predict weak-lensing peak counts in simulations. The local-Gaussianized transformation is insufficient to explain weak-lensing peak counts in the absence of shape noise. The prediction by local-Gaussianized transformation underestimates the simulated peak counts with a level of ∼20–30 per cent over a wide range of peak heights. Local-Gaussianized transformation can predict the weak-lensing peak counts with an ∼10 per cent accuracy in the presence of shape noise. Our analyses suggest that the cosmological information beyond power spectrum and its moments would be necessary to predict the weak-lensing peak counts with a percent-level accuracy, which is an expected statistical uncertainty in upcoming wide-field galaxy surveys.