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Title: Cosmology Constraints from the Weak Lensing Peak Counts and the Power Spectrum in CFHTLenS

Lensing peaks have been proposed as a useful statistic, containing cosmological information from non-Gaussianities that is inaccessible from traditional two-point statistics such as the power spectrum or two-point correlation functions. Here we examine constraints on cosmological parameters from weak lensing peak counts, using the publicly available data from the 154 deg2 CFHTLenS survey. We utilize a new suite of ray-tracing N-body simulations on a grid of 91 cosmological models, covering broad ranges of the three parameters Ωm, σ8, and w, and replicating the galaxy sky positions, redshifts, and shape noise in the CFHTLenS observations. We then build an emulator that interpolates the power spectrum and the peak counts to an accuracy of ≤ 5%, and compute the likelihood in the three-dimensional parameter space (Ωm, σ8, w) from both observables. We find that constraints from peak counts are comparable to those from the power spectrum, and somewhat tighter when different smoothing scales are combined. Neither observable can constrain w without external data. When the power spectrum and peak counts are combined, the area of the error “banana” in the (Ωm, σ8) plane reduces by a factor of ≈ two, compared to using the power spectrum alone. For a flat Λ coldmore » dark matter model, combining both statistics, we obtain the constraint σ8m/0.27)0.63 = 0.85+0.03-0.03.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Department of Astronomy and Astrophysics, Columbia University, New York, NY, (United States)
  2. Physics Department, Brookhaven National Laboratory, Upton, NY, (United States)
  3. Department of Physics, Columbia University, New York, NY, (United States)
  4. Department of Astronomy and Astrophysics, Columbia University, New York, NY, (United States); Institute for Strings, Cosmology, and Astroparticle Physics (ISCAP), Columbia University, New York, (United States)
  5. Department of Physics, Columbia University, New York, NY, (United States); Institute for Strings, Cosmology, and Astroparticle Physics (ISCAP), Columbia University, New York, (United States)
  6. Astrophysics and Cosmology Research Unit, University of KwaZulu-Natal, Westville, Durban, (South Africa)
Publication Date:
OSTI Identifier:
1174105
Report Number(s):
BNL--107476-2015-JA
Journal ID: ISSN 1550-7998; KA2301020
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 91; Journal Issue: 6; Journal ID: ISSN 1550-7998
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS