Galaxy redshifts with FLAIR

Abstract

<p>A redshift catalogue for a magnitude limited sample (B_j_ <= 16.5) of 116 galaxies obtained from COSMOS data of ESO/SERC survey field 352 is presented. The majority (100) were obtained with the FLAIR multi-object spectroscopy system on the 1.2-m U.K. Schmidt telescope of the Anglo-Australian Observatory (UKST). The multi-object capability and wide area coverage of the FLAIR system enable it to compete effectively with single-object spectrographs on 2-metre class on the comparison of data obtained in the blue and red spectral regions. Redshifts accurate to ~ 140 km s^-1^ in the blue spectral region and ~ 60 km s^-1^ in the red can be obtained for up to 35 objects simultaneously over the UKST's 40 deg^2^ field. This can be achieved in ~ 1800 seconds for red exposures of emission-line galaxies with B_j_ <= 17.8. For most normal galaxies, observing in the blue, the practical magnitude limit is B_j_ <= 16.8, with sufficient S/N being collected typically after 9000 seconds exposure. This limit is still ~ 2 magnitudes fainter than the original CfA redshift survey and makes the FLAlR system ideal for redshift surveys covering large areas of sky to moderate depth (~ 200 h^-1^ Mpc). The data acquired are extremely stable and are very straightforward to reduce, despite the somewhat rudimentary nature of the spectrograph. A new system--FLAIR 2, currently under development--will incorporate an optimised spectrograph, and will permit the use of ~ 100 fibres.</p>