Mass and light in the universe

We present a weak lensing and photometric study of six 0.degrees5 x 0.degrees5 fields observed at the Canada-France-Hawaii Telescope using the UH8K CCD mosaic camera. The fields were observed for a total of 2 hr each in I and V, resulting in catalogs containing similar to 20,000 galaxies per passband per field. We use V - I color and I magnitude to select bright early-type galaxies at redshifts 0.1 < z < 0.9. We measure the gravitational shear from faint galaxies in the range 21 < m(I) < 25 from a composite catalog and find a strong correlation with that predicted from the early types if they trace the mass with M/L-B similar or equal to 300 +/- 75 h M./L. for a flat (Omega (m0) = 0.3, Omega (lambda0) = 0.7) lambda cosmology and M/L-B similar or equal to 400 +/- 100 h M./L. for Einstein-de Sitter. We make two-dimensional reconstructions of the mass surface density. Cross-correlation of the measured mass surface density with that predicted from the early-type galaxy distribution shows a strong peak at zero lag (significant at the 5.2 sigma level). We azimuthally average the cross-correlation and autocorrelation functions. We conclude that the profiles are consistent with early-type galaxies tracing mass on scales of greater than or equal to 45 " (greater than or equal to 200 h(-1) kpc at z = 0.5). We subdivide our bright early-type galaxies by redshift and obtain similar conclusions. These M/L-B ratios imply Omega (m0) similar or equal to 0.10 +/- 0.02 (Omega (m0) similar or equal to 0.13 +/- 0.03 for Einstein-de Sitter) of closure density.