Near-IR Surveys (Objectives b, c) Another activity will be to capitalise on the near-IR surveys from the UKIRT Wide Field Camera (WFCAM) in the North, due to start taking data in 2003, and to prepare for the even more ambitious NIR surveys to be made by VISTA in the South. UKIRT will focus on a very large survey known as UKIDSS (UKIRT Deep Sky Survey). Scientific exploitation of the databases will be to make surveys to detect galaxy clusters out to z>1 and to extend the wavelength range to determine photometric redshifts more accurately, particularly for early type galaxies at higher redshift. This will include an investigation of the efficiency of combining colour and overdensity as ways of detecting high redshift clusters in K limited data and to use the currently existing photometric and redshift data to evaluate the methods for photometric redshifts including the weighting given to the various bands. An investigation of the effects of photometric errors on redshift accuracy will also be undertaken. Imaging Dark Matter via Weak Lensing (Objectives a, b, c) Analysis of the WHT CNOC weak lensing survey of galaxy groups and clusters will be continued through to completion. In the future, deep optical imaging with VST and VISTA forms a clear, new route to imaging Dark Matter using Weak Lensing. The goal will be to make real measurements of the shear and turn these into accurate measurements of the projected mass density in a given direction. An important aspect of this quantitative work is to develop more refined techniques to control systematic effects. Narrow-band imaging (Objectives a, b, c) An investigation of the potential advantages of narrow band imaging for photometric redshifts using both a theoretical approach and also using the available data from the CADIS survey will be undertaken. In particular areas where the CADIS survey overlaps the 2dF galaxy survey in order to compare narrow band ‘spectra’ and fibre spectra. The photometric redshift technique has pivotal importance for many of the galaxy and galaxy cluster survey projects and much better redshift accuracy may be possible using narrower bands. The MPIA CADIS 2 of 10
SISCO collaboration has the leading experience world-wide in making narrow-band surveys. Particularly interesting are areas where the CADIS Survey overlaps the 2dF-galaxy survey where narrow band “spectra” and fibre spectra can be compared. Spectral searches for Lyman alpha emission from proto-galactic gas will also be undertaken using facilities at ESO-VLT and Keck. High Redshift Galaxy Z-space Distortion (Objectives b, c) The future possibility of carrying out studies of the large-scale structure of the Universe at z 3, using spectroscopic redshifts from such instruments as VLT VIRMOS, will be explored. It will thus be possible to use geometric and dynamical redshift space distortion techniques similar to those used for 2dF QSOs to obtain new constraints on and m . The strength of the resulting statistical constraint on these parameters will be investigated to see what size of high redshift galaxy survey may be competitive with that from the 2dF QSOs.
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