Abstract details

There is increasing evidence for high-redshift bimodality in the distribution of galaxy colours as evidenced in WHDF, COMBO-17 and SDSS datasets. However, new observations in the WHDF at $z\approx0.4$, backed up by 2dF/SDSS observations at $z<0.3$ suggest that there is also evidence for an intermediate population of `blue' early-type galaxies. At $z\approx$0.5, these galaxies constitute about half the early-type population and it is important to know their origin. They may be the counterparts in the field of the blue `Butcher-Oemler' galaxies found in clusters and could correspond to mergers or spirals in the process of transforming into SOs.