### Probing Cosmology with Weak Lensing Minkowski Functionals and Peak Counts

Jan Michael Kratochvil

University of Miami

**Abstract:**

In two recent papers we study the cosmological origin of peaks in weak
gravitational lensing (WL) convergence maps, and show that Minkowski
Functionals (MFs) of WL maps contain significant non-Gaussian,
cosmology-dependent information. To do this, we produce a large suite
of cosmological ray-tracing N-body simulations to create mock WL
convergence maps. For the origin of the peaks, we study which halos in
the simulations get pierced by which light rays in the WL maps. For
the MF constraints, we study the cosmological information content of
MFs derived from these maps. Our suite consists of 80 independent
512^3-particle N-body runs, covering seven different cosmologies,
varying three cosmological parameters Omega_m, w, and sigma_8 one at a
time, around a fiducial LambdaCDM model. In each cosmology, we use
ray-tracing to create a thousand pseudo-independent 12 deg^2
convergence maps, and use these in a Monte Carlo procedure to estimate
the joint confidence contours on the above three parameters. We
include redshift tomography at three different source redshifts z_s=1,
1.5, 2, explore five different smoothing scales theta_G=1, 2, 3, 5, 10
arcmin, and explicitly compare and combine the MFs with the WL power
spectrum. We find that the MFs capture a substantial amount of
information from non-Gaussian features of convergence maps, i.e.
beyond the power spectrum. The MFs are particularly well suited to
break degeneracies and to constrain the dark energy equation of state
parameter w (by a factor of ~ three better than from the power
spectrum alone). The non-Gaussian information derives partly from the
one-point function of the convergence (through V_0, the "area" MF),
and partly through non-linear spatial information (through combining
different smoothing scales for V_0, and through V_1 and V_2, the
boundary length and genus MFs, respectively). In contrast to the power
spectrum, the best constraints from the MFs are obtained only when
multiple smoothing scales are combined.