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Session 27 - Gravitational Lensing & Dark Matter.
Oral session, Monday, January 13
Frontenac Ballroom,

[27.06] Galaxy-galaxy Lensing

R. Blandford (CalTech)

Intervening deflector galaxies modify the shapes of background source galaxies in the sense that they become tangentially stretched. The quantitative measure of this effect provides a combined measurement of the depth and size of the dark matter gravitational potential wells formed by distant galaxies and the redshift distribution of the source and lens galaxies. A statistical study of this effect using data acquired with the 5m Hale reflector proiduced a marginally significant measurement consistent with distant galaxies having properties similar to those that we find in local galaxies. An improved analysis is possible if we know the redshift distribution of sufficient source galaxies and have excellent imaging. Fortunately both conditions have been satisfied with recent observations of the Hubble Deep Field. The power of this technique will be demonstrated, preliminary results from the deep field will be presented and future prospects wil be briefly outlined.

Program listing for Monday