THE ESO SLICE PROJECT (ESP) GALAXY REDSHIFT SURVEY .1. DESCRIPTION AND FIRST RESULTS

The ESO Slice Project (ESP) is a galaxy redshift survey we have recent ly completed as an ESO Key-Project. The ESP covers 23.3 square degrees in a region close to the South Galactic Pole. The survey is nearly co mplete (85%) to the limiting magnitude b(J) = 19.4 and consists of 334 2 galaxies with reliable redshift determination. In this paper, the fi rst in a series that will present the results of the ESP survey, we de scribe the main characteristics of the survey and briefly discuss the properties of the galaxy sample. From a preliminary spectral analysis of a large sub-sample of 2550 galaxies we find that the fraction of ac tively star-forming galaxies increases from a few percent for the brig htest galaxies up to about 40% for the galaxies fainter than M = -16.5 +5 log h. The most outstanding feature in the ESP redshift distributi on is a very significant peak at z similar or equal to 0.1. The detect ion of similar peaks, at the same distance, in other surveys in the sa me region of the sky, suggests the presence of a large bidimensional s tructure perpendicular to the line of sight. The minimum size of this structure would be of the order of 100 x 50 h(-1) Mpc, comparable with the size of the Great Wall.