Non-Gaussian information from weak lensing data via deep learning
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Weak lensing maps contain information beyond two-point statistics on small scales. Much recent work has tried to extract this information through a range of different observables or via nonlinear transformations of the lensing field. Here we train and apply a 2D convolutional neural network to simulated noiseless lensing maps covering 96 different cosmological models over a range of Ω_m,σ_8. Using the area of the confidence contour in the Ω_m,σ_8 plane as a figure-of-merit, derived from simulated convergence maps smoothed on a scale of 1.0 arcmin, we show that the neural network yields ≈ 5 × tighter constraints than the power spectrum, and ≈ 4 × tighter than the lensing peaks. Such gains illustrate the extent to which weak lensing data encode cosmological information not accessible to the power spectrum or even non-Gaussian statistics such as lensing peaks.
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