A survey of galaxy redshifts. I - Data reduction techniques

Abstract

A magnitude-limited redshift survey of galaxies having B magnitudes no fainter than 14.5, galactic latitudes no less than 40 deg, and nonnegative declinations is currently being undertaken. This paper presents in some detail the methods of data reduction, which are based on cross correlation against filtered templates. Expressions are presented for the uncertainty of a measured redshift, for the internal broadening of the object, and for the uncertainty of this broadening. Comparison of the optical data with previously published 21-cm data shows no systematic errors and yields excellent agreement with the internal error analysis. The method of analyzing velocity dispersions is quite promising for further application. A series of spectra are presented as examples to show the power and limitations of the correlation techniques.