Cosmology constraints from shear peak statistics in Dark Energy Survey Science Verification data
Abstract
Shear peak statistics has gained a lot of attention recently as a practical alternative to the twopoint statistics for constraining cosmological parameters. We perform a shear peak statistics analysis of the Dark Energy Survey (DES) Science Verification (SV) data, using weak gravitational lensing measurements from a 139 deg^{2} field. We measure the abundance of peaks identified in aperture mass maps, as a function of their signaltonoise ratio, in the signaltonoise range 0<S/N<4. To predict the peak counts as a function of cosmological parameters, we use a suite of Nbody simulations spanning 158 models with varying Ω_{m} and σ_{8}, fixing w = 1, Ω_{b} = 0.04, h = 0.7 and n_{s} = 1, to which we have applied the DES SV mask and redshift distribution. In our fiducial analysis we measure σ_{8}(Ω_{m}/0.3)^{0.6} = 0.77 ± 0.07, after marginalizing over the shear multiplicative bias and the error on the mean redshift of the galaxy sample. We introduce models of intrinsic alignments, blending and source contamination by cluster members. These models indicate that peaks with S/N>4 would require significant corrections, which is why we do not include them in our analysis. We compare our results to the cosmological constraints from the twopoint analysis on the SV field and find them to be in good agreement in both the central value and its uncertainty. We discuss prospects for future peak statistics analysis with upcoming DES data.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 December 2016
 DOI:
 10.1093/mnras/stw2070
 arXiv:
 arXiv:1603.05040
 Bibcode:
 2016MNRAS.463.3653K
 Keywords:

 gravitational lensing: weak;
 methods: data analysis;
 methods: statistical;
 cosmological parameter;
 cosmology: observations;
 dark matter;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 21 pages, 14 figures, submitted to MNRAS