Cross-correlating Sunyaev-Zel'dovich and Weak Lensing Maps
  We present novel statistical tools to cross-correlate frequency cleaned
thermal Sunyaev-Zel'dovich (tSZ) maps and tomographic weak lensing (wl)
convergence maps. Moving beyond the lowest order cross-correlation, we
introduce a hierarchy of mixed higher-order statistics, the cumulants and
cumulant correlators, to analyze non-Gaussianity in real space, as well as
corresponding polyspectra in the harmonic domain. Using these moments, we
derive analytical expressions for the joint two-point probability distribution
function (2PDF) for smoothed tSZ (y_s) and convergence (\kappa_s) maps. The
presence of tomographic information allows us to study the evolution of higher
order {\em mixed} tSZ-weak lensing statistics with redshift. We express the
joint PDFs p_{\kappa y}(\kappa_s,y_s) in terms of individual one-point PDFs
(p_{\kappa}(\kappa_s), p_y(y_s)) and the relevant bias functions
(b_{\kappa}(\kappa_s), b_y(y_s)). Analytical results for two different regimes
are presented that correspond to the small and large angular smoothing scales.
Results are also obtained for corresponding {\em hot spots} in the tSZ and
convergence maps. In addition to results based on hierarchical techniques and
perturbative methods, we present results of calculations based on the lognormal
approximation. The analytical expressions derived here are generic and
applicable to cross-correlation studies of arbitrary tracers of large scale
structure including e.g. that of tSZ and soft X-ray background.
