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Astron. Astrophys. 351, 815-826 (1999)

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Cosmic shear and halo abundances: analytical versus numerical results

K. Reblinsky 1, G. Kruse 1, B. Jain 2 and P. Schneider 1

1 Max-Planck-Institut für Astrophysik, Postfach 1523, 85740 Garching, Germany
2 Johns Hopkins University, Department of Physics, Baltimore, MD 21218, USA

Received 25 June 1999 / Accepted 17 September 1999


The aperture mass has been shown in a series of recent publications to be a useful quantitative tool for weak lensing studies, ranging from cosmic shear to the detection of a mass-selected sample of dark matter haloes. Quantitative analytical predictions for the aperture mass have been based on a number of simplifying assumptions. In this paper, we test the reliability of these assumptions and the quality of the analytic approximations, using ray-tracing simulations through a cosmological density field generated by very large N-body simulations. We find that those analytic predictions which take into account the non-linear evolution of the matter distribution, such as the dispersion of the aperture mass and the halo abundance, are surprisingly accurately reproduced with our numerical results, whereas the predictions for the skewness, based on quasi-linear theory, are rather imprecise. In particular, we verify numerically that the probability distribution of the aperture mass decreases exponentially for values much larger than the rms. Given the good overall agreement, comparisons between the observed distribution of the aperture mass and the theoretical values provide a powerful tool for testing cosmological models.

Key words: cosmology: theory – cosmology: dark matter – cosmology: gravitational lensing – cosmology: large-scale structure of Universe – methods: numerical

Send offprint requests to: Katrin Reblinsky (reblinsk@mpa-garching.mpg.de)

© European Southern Observatory (ESO) 1999

Online publication: November 16, 1999