THE ESO-SCULPTOR FAINT GALAXY REDSHIFT SURVEY - THE SPECTROSCOPIC SAMPLE

In the goal to probe the distribution of galaxies at redshifts z simil ar or equal to 0.1 - 0.5, we have started a deep redshift survey Limit ed by R less than or equal to 20.5. Using multiple object spectroscopy on the 2 largest telescopes at the European Southern Observatory, we have so far obtained 491 low-resolution spectra (similar to 10-20 Angs trom FWHM) of faint galaxies. Among the 386 spectra of galaxies with R less than or equal to 20.5, redshifts have been measured for 320 obje cts (81%). The spectra of 105 objects fainter than our catalogue limit (with R greater than or equal to 20.5) were also taken simultaneously and at no additionnal cost in observing time, and we derived redshift s for 47 of them (43%). In this article we describe the different meth ods which we are using to reduce the spectroscopic data in a homogeneo us way. Because of the low signal-to-noise ratio of the spectra, each step of the reduction must be optimized. Various tests are presented t o evaluate the quality of the reduced data, and the linearity and zero -point of the redshift scale are checked. Using the already available data, we present preliminary diagrams of the redshift distribution and the fraction of objects with emission-lines.