Wide Field Spectroscopy and the Universe

In this short survey of the applications of wide-field, multi-object spectroscopy to galaxy evolution, large-scale structure and cosmology, I interleave summaries of the general goals and state of play in these fields with specific examples based on my own recent work. I first briefly review the goals and figures of merit for current and future redshift surveys, before examining some recent results from deep surveys in the field, cluster redshift surveys and surveys of large scale structure. I take a look beyond redshift surveys to other probes of galaxy evolution before concluding with a discussion of the future prospects for such studies using the next generation of wide-field, multi-object spectrographs on large telescopes. The main goals of extragalactic/cosmological studies for which widefield, multi-object spectroscopy is relevant are (i) the world model: H0, q0, Ω, Λ, etc.; (ii) large-scale structure: P (k), ξ(r), Gaussianity, topology, morphology, biassing, etc.; and (iii) galaxy formation and evolution: luminosity function and ξ(r) as functions of galaxy type, environment and lookback time, the redshift of peak star formation in bulges and disks, etc. Redshift surveys are essential to some of these topics and one powerful alternative in studying others, either because they are intrinsically population studies or because they demand large statistical samples. In either case one is playing a numbers game, so that the most efficient observational approach will employ wide-field multi-object spectroscopy.