A limit on the number density of bright z ~ 7 galaxies

International audienceWe present a survey of bright optical dropout sources in two deep, multiwavelength surveys comprising 11 widely separated fields, aimed at constraining the galaxy luminosity function at z ~ 7 for sources at 5-10L*(z = 6). Our combined survey area is 225arcmin2 to a depth of JAB = 24.2 (3sigma) and 135arcmin2 to J = 25.3 (4sigma). We find that infrared data longwards of 2mum are essential for classifying optical dropout sources, and in particular for identifying cool Galactic star contaminants. Our limits on the number density of high-redshift sources are consistent with current estimates of the Lyman break galaxy luminosity function at z = 6