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Title: Probing cosmology with weak lensing peak counts

Abstract

We propose counting peaks in weak lensing (WL) maps, as a function of their height, to probe models of dark energy and to constrain cosmological parameters. Because peaks can be identified in two-dimensional WL maps directly, they can provide constraints that are free from potential selection effects and biases involved in identifying and determining the masses of galaxy clusters. As a pilot study, we have run cosmological N-body simulations to produce WL convergence maps in three models with different constant values of the dark energy equation-of-state parameter, w=-0.8, -1, and -1.2, with a fixed normalization of the primordial power spectrum (corresponding to present-day normalizations of {sigma}{sub 8}=0.742, 0.798, and 0.839, respectively). By comparing the number of WL peaks in eight convergence bins in the range of -0.1<{kappa}<0.4, in multiple realizations of a single simulated 3x3 degree field, we show that the first (last) pair of models differ at the 95% (85%) confidence level. A survey with depth and area comparable to those expected from the Large Synoptic Survey Telescope should have a factor of {approx_equal}50 better parameter sensitivity. These results warrant further investigation, in order to assess the constraints available when marginalization over other uncertain parameters is included, and withmore » the specifications of a realistic survey folded into the analysis. Here we find that relatively low-amplitude peaks ({kappa}{approx}0.03), which typically do not correspond to a single collapsed halo along the line of sight, account for most of the parameter sensitivity. We study a range of smoothing scales and source galaxy redshifts (z{sub s}). With a fixed source galaxy density of 15 arcmin{sup -2}, the best results are provided by the smallest scale we can reliably simulate, 1 arcmin, and z{sub s}=2 provides substantially better sensitivity than z{sub s{<=}}1.5.« less

Authors:
 [1];  [1];  [2]
  1. Institute for Strings, Cosmology, and Astroparticle Physics (ISCAP), Columbia University, New York, New York 10027 (United States)
  2. Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
Publication Date:
OSTI Identifier:
21409273
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 81; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevD.81.043519; (c) 2010 The American Physical Society; Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CONVERGENCE; COSMOLOGY; DENSITY; EQUATIONS OF STATE; GALAXIES; GALAXY CLUSTERS; MASS; NONLUMINOUS MATTER; RED SHIFT; SENSITIVITY; SIMULATION; SPECTRA; TELESCOPES; TWO-DIMENSIONAL CALCULATIONS; EQUATIONS; MATTER; PHYSICAL PROPERTIES

Citation Formats

Kratochvil, Jan M, Haiman, Zoltan, Department of Astronomy, Columbia University, New York, New York 10027, and May, Morgan. Probing cosmology with weak lensing peak counts. United States: N. p., 2010. Web. doi:10.1103/PHYSREVD.81.043519.
Kratochvil, Jan M, Haiman, Zoltan, Department of Astronomy, Columbia University, New York, New York 10027, & May, Morgan. Probing cosmology with weak lensing peak counts. United States. https://doi.org/10.1103/PHYSREVD.81.043519
Kratochvil, Jan M, Haiman, Zoltan, Department of Astronomy, Columbia University, New York, New York 10027, and May, Morgan. 2010. "Probing cosmology with weak lensing peak counts". United States. https://doi.org/10.1103/PHYSREVD.81.043519.
@article{osti_21409273,
title = {Probing cosmology with weak lensing peak counts},
author = {Kratochvil, Jan M and Haiman, Zoltan and Department of Astronomy, Columbia University, New York, New York 10027 and May, Morgan},
abstractNote = {We propose counting peaks in weak lensing (WL) maps, as a function of their height, to probe models of dark energy and to constrain cosmological parameters. Because peaks can be identified in two-dimensional WL maps directly, they can provide constraints that are free from potential selection effects and biases involved in identifying and determining the masses of galaxy clusters. As a pilot study, we have run cosmological N-body simulations to produce WL convergence maps in three models with different constant values of the dark energy equation-of-state parameter, w=-0.8, -1, and -1.2, with a fixed normalization of the primordial power spectrum (corresponding to present-day normalizations of {sigma}{sub 8}=0.742, 0.798, and 0.839, respectively). By comparing the number of WL peaks in eight convergence bins in the range of -0.1<{kappa}<0.4, in multiple realizations of a single simulated 3x3 degree field, we show that the first (last) pair of models differ at the 95% (85%) confidence level. A survey with depth and area comparable to those expected from the Large Synoptic Survey Telescope should have a factor of {approx_equal}50 better parameter sensitivity. These results warrant further investigation, in order to assess the constraints available when marginalization over other uncertain parameters is included, and with the specifications of a realistic survey folded into the analysis. Here we find that relatively low-amplitude peaks ({kappa}{approx}0.03), which typically do not correspond to a single collapsed halo along the line of sight, account for most of the parameter sensitivity. We study a range of smoothing scales and source galaxy redshifts (z{sub s}). With a fixed source galaxy density of 15 arcmin{sup -2}, the best results are provided by the smallest scale we can reliably simulate, 1 arcmin, and z{sub s}=2 provides substantially better sensitivity than z{sub s{<=}}1.5.},
doi = {10.1103/PHYSREVD.81.043519},
url = {https://www.osti.gov/biblio/21409273}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 4,
volume = 81,
place = {United States},
year = {Mon Feb 15 00:00:00 EST 2010},
month = {Mon Feb 15 00:00:00 EST 2010}
}