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Effects of the complex mass distribution of dark matter halos on weak lensing cluster surveys
Gravitational lensing effects arise from the light ray deflection by all of
the mass distribution along the line of sight. It is then expected that weak
lensing cluster surveys can provide us true mass-selected cluster samples. With
numerical simulations, we analyze the correspondence between peaks in the
lensing convergence -map and dark matter halos. Particularly we
emphasize the difference between the peak value expected from a dark
matter halo modeled as an isolated and spherical one, which exhibits a
one-to-one correspondence with the halo mass at a given redshift, and that of
the associated -peak from simulations. For halos with the same expected
, their corresponding peak signals in the -map present a wide
dispersion. At an angular smoothing scale of , our
study shows that for relatively large clusters, the complex mass distribution
of individual clusters is the main reason for the dispersion. The projection
effect of uncorrelated structures does not play significant roles. The
triaxiality of dark matter halos accounts for a large part of the dispersion,
especially for the tail at high side. Thus lensing-selected clusters
are not really mass-selected. (abridged)Comment: ApJ accepte
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