Assigned ID: 560 ----- Submission 1 (Fri Jan 21 23:42:19 GMT 2005) ----- Phase I Proposal 560 (cycle14b) successfully submitted. ----- Submission 3 (Fri Jan 21 23:49:00 GMT 2005) ----- We propose to use existing ACS images to derive, for the first time, solid measurements of the ratio of dynamical and halo masses for a sample of distant, and thus younger, galaxies using the technique of galaxy-galaxy lensing. The 2 filter HST images are critical in providing both the weak lensing signals to derive the halo masses, and the set of information (inclination, size, position angle, and emission line distribution) needed to convert spatially resolved Keck spectra into dynamical masses. Besides dynamical masses, the multiband ACS images are essential for extracting morphological, photometric, and structural information for the distant galaxies. We plan to use 3 ACS surveys with 2 or more filters (GOODS-N, GOODS-S, and the Extended Groth Strip) for this analysis. The wide areal coverage of these fields (900 sqarcmin) will allow us to improve on previous lensing results in the Hubble Deep Field by a factor of 20 in signal-to-noise ratio. With over 4500 kinematic measurements and 1000 rotation curves to be studied via galaxy-galaxy lensing, the sample enables powerful new tests of the relationship of halo masses of younger galaxies to not only dynamical masses, but also to subsets divided by redshift, luminosity, morphology, B/T, color, etc. The direct measurements of the connections between dark matter halos and their baryonic galaxies provide fundamental knowledge and checks of the reigning LCDM models for galaxy formation.

GALAXIES 12 97930 false 0.0 false false false false false SUPPORTED