An exponential decline at the bright end of the z=6 galaxy luminosity function

Understand

We present the results of a search for the most luminous star-forming galaxies at redshifts z~6 based on CFHT Legacy Survey data.

• We identify a sample of 40 Lyman break galaxies brighter than magnitude z'=25.3 across an area of almost 4 square degrees.
• Sensitive spectroscopic observations of seven galaxies provide redshifts for four, of which only two have moderate to strong Lyman alpha emission lines.
• All four have clear continuum breaks in their spectra.