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Session 103 - Galaxy Evolution.
Display session, Thursday, January 16
Metropolitan Ballroom,

[103.09] Formation and Evolution of Spheroidal Galaxies in the Hubble Deep Field.

F. Marleau, T. Broadhurst (UCB)

We examine the evolution of spheroidal galaxies in the Hubble Deep Field (HDF) images. The surface brightness profiles of all compact objects are compared with two-dimensional de Vaucouleurs profiles, yielding 32 objects which fit well in the I_814 passband. Most of these galaxies (22) form a very tight colour-magnitude sequence extending to very red colours at faint magnitude, consistent with passive evolution to z\sim1.5. The remainder (10) are much bluer and their location in the colour-magnitude plane indicates they are at high redshift undergoing their initial star-formation episode. The narrow width of the red sequence requires a declining faint-end luminosity function (\alpha\sim=-0.3), consistent with lower redshift estimates. Subtraction of the model profiles from the images reveals an AGN, shells and candidate lensed images.

Program listing for Thursday