Ray Tracing Simulations of Weak Lensing by Large-Scale Structure

Details Ray Tracing Simulations of Weak Lensing by Large-Scale Structure Ray Tracing Simulations of Weak Lensing by Large-Scale Structure

1999-01-14

arxiv.org/abs/astro-ph/9901191v2

Astrophys.J.530:547,2000

Astronomy and Astrophysics

Astrophysics

59 pages, 22 figures included. Matches version accepted for ApJ

Scientific paper

10.1086/308384

We investigate weak lensing by large-scale structure using ray tracing through N-body simulations. Photon trajectories are followed through high resolution simulations of structure formation to make simulated maps of shear and convergence on the sky. Tests with varying numerical parameters are used to calibrate the accuracy of computed lensing statistics on angular scales from about 1 arcminute to a few degrees. Various aspects of the weak lensing approximation are also tested. For fields a few degrees on a side the shear power spectrum is almost entirely in the nonlinear regime and agrees well with nonlinear analytical predictions. Sampling fluctuations in power spectrum estimates are investigated by comparing several ray tracing realizations of a given model. For survey areas smaller than a degree on a side the main source of scatter is nonlinear coupling to modes larger than the survey. We develop a method which uses this effect to estimate the mass density parameter Omega from the scatter in power spectrum estimates for subregions of a larger survey. We show that the power spectrum can be measured accurately from realistically noisy data on scales corresponding to 1-10 Mpc/h. Non-Gaussian features in the one point distribution function of the weak lensing convergence (reconstructed from the shear) are also sensitive to Omega. We suggest several techniques for estimating Omega in the presence of noise and compare their statistical power, robustness and simplicity. With realistic noise Omega can be determined to within 0.1-0.2 from a deep survey of several square degrees.

Affiliated with

Also associated with

No associations

Rating

Ray Tracing Simulations of Weak Lensing by Large-Scale Structure does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Ray Tracing Simulations of Weak Lensing by Large-Scale Structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ray Tracing Simulations of Weak Lensing by Large-Scale Structure will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-597278