REFLEX galaxies redshifts

The REFLEX survey covers 4.24 steradians (34% of the entire sky) below a declination +2.50{deg} and at high galactic latitude (|b|<20{deg}). The full survey includes 447 galaxy clusters with a median redshift of 0.08 and is better than 90% complete to a limiting flux of f_X_=3x10^-12^ergs/s/cm^2^ (3fW/m^2^, 0.1 to 2.4keV), representing the largest statistically homogeneous sample of clusters to date drawn from the ROSAT All-Sky Survey (RASS).

Here we describe the details of the spectroscopic observations carried out at the ESO 1.5m, 2.2m and 3.6m telescopes, the data reduction and redshift measurements techniques. The spectra typically cover the wavelength range 3600-7500{AA} at a two-pixel resolution of ~14{AA} . From calibrations and external checks the redshifts are accurate to a typical rms error of +/-100km/s.