The Star Formation Density at z=7
Abstract
Description
Near-infrared VLT data of the GOODS-South area were used to look for galaxies at z=7 down to a limiting magnitude of (J+Ks)AB=25.5. No high-redshift candidates were detected, and this provides clear evidence for a strong evolution of the luminosity function between z=6 and z=7, i.e. over a time interval of only 170 Myr. Our constraints provide evidence of a significant decline in the total star formation rate at z=7, which must be less than 40% of that at z=3 and 40-80% of that at z=6. The resulting upper limit to the ionizing flux at z=7 is only marginally consistent with what is required to completely ionize the Universe.
to appear in the proceedings of "At the Edge of the Universe", Sintra, Portugal, October 2006
to appear in the proceedings of "At the Edge of the Universe", Sintra, Portugal, October 2006