Anglo-Australian Telescope Imaging and Microslit Spectroscopy in the Southern Hubble Deep Field

We present a deep photometric ( B - and R -band) catalog and an associated spectroscopic redshift survey conducted in the vicinity of the Hubble Deep Field-South. The spectroscopy yields 53 extragalactic redshifts in the range 0 < z < 1.4, substantially increasing the body of spectroscopic work in this field to over 200 objects. The targets are selected from deep Anglo-Australian Telescope prime-focus images complete to R < 24, and the spectroscopy is 50% complete at R = 23. There is now strong evidence for a rich cluster at z ≃ 0.58 flanking the Wide Field Planetary Camera 2 field, which is consistent with a known absorber of the bright QSO in this field. We find that photometric redshifts of z < 1 galaxies in this field based on Hubble Space Telescope data are accurate to σ z /(1 + z ) = 0.03 (albeit with small number statistics). The observations were carried out as a community service for Hubble Deep Field science in order to demonstrate the first use of the nod-and-shuffle technique with a classical multiobject spectrograph and to test the use of microslits for ultrahigh multiplex observations along with a new volume phase holographic grism and deep-depletion CCD. The reduction of this new type of data is also described.