Optimized detection of shear peaks in weak lensing maps

摘要: We present a new method to extract cosmological constraints from weak lensing (WL) peak counts, which we denote as ‘the hierarchical algorithm’. The idea of this is combine information WL maps sequentially smoothed with series filters different size, the largest down smallest, thus increasing sensitivity resulting function. compare abundance measured in way and obtained by using filter fixed standard practice studies. For purpose, employ large set generated ray tracing through N-body simulations, Fisher matrix formalism. find that if low signal-to-noise ratio () peaks are included analysis (), yields significantly better than single-sized filtering. future survey such Euclid or Large Synoptic Survey Telescope, combined cosmic microwave background experiment like Planck, results for (single-sized) Δns= 0.0039 (0.004), ΔΩm= 0.002 (0.0045), Δσ8= 0.003 (0.006) Δw= 0.019 (0.0525). This forecast conservative, assume no knowledge redshifts lenses, consider single broad bin sources. If only considered, then there little difference between two methods. also examine statistical properties function: Its covariance has off-diagonal terms bins aperture mass M < 3 × 1014 h−1 M⊙, higher being largely uncorrelated therefore well described Poisson distribution.