Gravity and nongravity modes in the VIRMOS-DESCART weak-lensing survey

We analyze the weak-lensing data of the VIRMOS imaging survey using projections (called E- and B-modes) of the two independent observable correlation functions. The E-mode contains all the lensing signal, while noise and systematics contribute equally to the E-and B-modes provided that intrinsic alignment is negligible. The mode separation allows a measurement of the signal with root2 smaller error bars and a separate channel to test for systematic errors. We apply various transformations, including a spherical harmonic space power spectrum C-l(E) and C-l(B), which provides a direct measurement of the projected dark matter distribution for 500 < l < 10(4).