High Z evolution of optically and IR-selected galaxies

We use a combination of public imaging surveys to collect a sample of 1712 I-selected and 319 K less than or equal to 21 galaxies observed from the U to the K band. The photometric redshift distribution of the K less than or equal to 21 sample has only 5% of galaxies detected at z greater than or equal to 2: this result strongly supports hierarchical scenarios where present-day massive galaxies are the result of merging processes. The observed UV luminosity density in the I-selected sample is confined within a factor of 4 over the whole range 0 < z < 4.5, in agreement with previous spectroscopic and photometric surveys. CDM models in Lambda -dominated universe are in good agreement at 3 less than or equal to z less than or equal to 4.5, but predict a pronounced peak at z similar or equal to 1.5 and a drop by a factor of 8 from z = 1.5 to z = 4 that is not observed in the data.