DETECTION OF CANDIDATE LY-ALPHA-EMITTING GALAXIES AT Z=5.7

We report the detection of seven candidate Ly alpha-emitting galaxies which have been found during the preliminary phase of the 'Calar Alto Deep Imaging Survey' (CADIS). They are selected from 147 emission-line galaxies detected in a field of 60 arcmin(2) with a Fabry-Perot inter ferometer, following the exclusion of 140 sources identified as foregr ound galaxies by a combination of broad-and narrow-band filters. Altho ugh no conclusive spectroscopic confirmation is yet available, we expe ct from an analysis of possible residual contamination by foreground o bjects that two or more of the candidates will turn out to be genuine Ly alpha-emitting primeval galaxies at a redshift of z=5.7. For a flat universe (q(0)=0.5) this would be in perfect agreement with refined p redictions of the abundance of primeval galaxies and various recent re sults on the space density of young galaxies at z less than or equal t o 4.5.