Invited review at the 19th Texas Symposium on Relativistic Astrophysics and Cosmology, eds. J. Paul, T. Montmerle, and E. Aubourg; astro-ph/9911115


LARGE-SCALE STRUCTURE AT THE TURN OF THE MILLENNIUM

Luigi Guzzo

Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807, Merate, Italy
Email: guzzo@merate.mi.astro.it


Abstract. I review the current status of studies of the large-scale structure of the Universe using redshift surveys of galaxies and clusters of galaxies. I first summarise the advances we have made in our knowledge of the cosmography of the z < 0.2 Universe during the last 25 years, as well as the status of the major surveys in progress. The question of how the a priori selection of some classes of objects biases the mapping of the underlying mass density field is discussed in some detail. I then emphasise the advantages of using clusters of galaxies selected in the X-ray band as tracers of large-scale structure, summarising the most recent results of the REFLEX survey, which is under completion. The strong potential of using X-ray clusters to study the evolution of structure to large redshifts is underlined. I then summarise some of the most recent statistical results on the clustering of galaxies and clusters, using the two-point correlation function xi(s) and the power spectrum P(k). In particular, I concentrate on the increased information available on the detailed shape of these functions on large scales, λ ~ 100 h-1 Mpc. I argue that significant evidence is accumulating from different observations that the power spectrum has a well-defined and possibly narrow peak around k ~ 0.05 h Mpc-1. In the near future, measures of P(k) from the full REFLEX survey, from the 2dF survey, and in particular from the SDSS large-volume subsamples will be crucial checks for these indications. I conclude with a glimpse into the future of large-scale structure surveys at high redshifts, describing the features of the VIRMOS deep survey, which will soon start collecting redshifts with the ESO VLT for ~ 150,000 galaxies at a typical depth of z = 1.


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