A. P. Oates

The Durham/UKST Galaxy Redshift Survey

We are currently engaged in a long-term project to make a redshift survey of ~ 4000 galaxies based on the Durham/ROE Southern Galaxy Catalogue (Collins et al., 1988) which is a COSMOS survey of the 2D distribution of b j > 20.5m galaxies over 60 UK Schmidt Telescope (UKST) fields. The current programme makes further use of the UKST in conjunction with FLAIR, a fibre-coupled spectroscopy system. The ultimate aim is to map the 3D distribution of galaxies over all 60 high galactic latitude fields by making a 1-in-3 random sampled redshift survey of b j ≲ 16.75m galaxies. We are currently able to observe 61 galaxies simultaneously per 5° x 5° field using the Durham dual CCD camera coupled to 2 FLAIR spectrographs.

CCD detector for multiple object spectroscopy at the United Kingdom Schmidt Telescope

The standard CCD used in the camera installed at the Schmidt Telescope has a poor short wavelength response and so all the CCDs are surface coated with a fluorescent dye to partially overcome this problem. In 1988 it was decided that the systems response around 4000 A could be improved further by replacing the FLAIR (fiber linked array image reformatter) fibers with a set of fibers offering superior transmission properties at this wavelength. The introduction of these larger core diameter fibers would have meant, however, accepting a reduction in signal-to-noise as the fibers illuminate more pixels on the CCD. The CCD sequencing was therefore modified to permit pixel binning across the dispersion direction. Recent modifications also provide a detection capability for approximately twice the number of objects, by appending a second CCD detector and correlated double sample processor to the existing sequencer. Both CCDs are operated via a signal controller which can route clocks and video between the detectors and sequencing electronics. Reduction of galaxy data show that FLAIR, combined with a low noise detector, in both single and dual CCD mode, is easily capable of obtaining cross-correlation redshifts in the blue with a high success rate.

Progress in Galaxy Redshift Surveys using FLAIR

Among the most important stimuli for developing the FLAIR multi-object spectroscopy system on the 1.2-m UK Schmidt Telescope was its potential for carrying out large-scale redshift surveys of galaxies of intermediate magnitude (B h −1 Mpc (where the parameter h is the Hubble constant expressed as a fraction of 100 kms −1 Mpc −1 ). In this paper we summarise the results from our redshift surveys to highlight the capabilities of FLAIR. We present a status report on the current large-scale survey, and show that the recently-introduced FLAIR II system will speed its progress considerably.

FLAIR wide-field multiobject spectroscopy system

The evolution, current status, and planned improvements of the FLAIR fiber-optic-link multiobject spectroscopy system used on the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory are reviewed and illustrated with diagrams and sample spectra. Consideration is given to the original FLAIR system using photographic film to record spectra, the introduction of a slow-scan cryogenic CCD camera in 1986, the problems of focal-surface coverage and sensitivity in the prototype FLAIR, the improved Panache fiber feed and on-chip pixel binning scheme installed in 1988, and the dispersion options offered by the FLAIR-Panache system. The limitations of the present FLAIR configuration are discussed, along with improvements involving (1) the use of a new spectrograph with Schmidt optics for both collimator and camera and (2) advanced plate-holder and positioner systems making it possible to load FLAIR into the telescope in a few seconds instead of an hour.