Keck Spectroscopy of the Hubble Deep Field

Spectra of 115 HDF galaxies to I 25 mag were obtained by the Santa Cruz DEEP group with the Keck LRIS multislit spectrograph and combined with detailed structural measurements from the HDF images to (i) derive evolution for a sample of disk galaxies at z 0:5 using the Tully-Fisher relation, (ii) characterize, from size and velocity width data, the global properties to z 1 of a sample of 60 \compact" galaxies, (iii) determine star formation rates in that \compact" sample, and (iv) derive structure and redshifts for a sample of U and B-band \dropout" objects, of which 11 have been connrmed to be at high redshift (z = 2:2 ? 3:5). 1 DEEP The DEEP Project a was developed with the goal of elucidating the physical processes and time scales of the formation and evolution of galaxies. The Keck telescopes and their multi-object spectrographs (LRIS and later DEIMOS) are central to this program. Of equal importance is the high spatial resolution imaging capability provided by HST and its WFPC2 camera (and NICMOS, plus the Advanced Camera, the ACS, in 1999). The structural and morphological information from wide-eld HST imaging has revolutionized the study of distant galaxies. The importance of such HST-imaged regions for the study of galaxies at intermediate to high redshift cannot be overstated. Ground-based telescopes, even with adaptive optical systems, will not provide comparable capability for the foreseeable future. 2 HDF Results For a speciic example of the importance of HST for clarifying the nature of galaxies in the young universe, one needs only to think of the impact of the Hubble Deep Field (Williams et al. 1996), and of the projects that the HDF images have precipitated. The rst results from the DEEP team's Keck LRIS observations of the HDF and its anking elds are available in four papers, and are summarized below. The results are based on samples of galaxies selected from the HDF to meet a number of scientiic goals. Structural parameters, colors, surface brightnesses a Deep Extragalactic Evolutionary Probe; for further information see the DEEP home page at