Average spectra of distant galaxies

Average spectra of VVDS galaxies in three redshift, i.e. distances or ages, ranges (top to bottom): 1.4 to 2.5, 2.5 to 3.5, and 3.5 to 5.0. The main spectral features expected at these wavelengths are clearly visible in all spectra. The VIMOS VLT Deep Survey (VVDS) started early 2002 on Melipal, one of the 8.2-m telescopes of ESO's Very Large Telescope Array. In a total sample of about 8,000 galaxies selected only on the basis of their observed brightness in red light, almost 1,000 bright and vigorously star forming galaxies were discovered that were formed between 9 and 12 billion years ago (i.e. about 1,500 to 4,500 million years after the Big Bang). This is two to six times higher than had been found previously. These galaxies had been missed because previous surveys had selected objects in a much more restrictive manner than we did. And they did so to accommodate the much lower efficiency of the previous generation of instruments.