Using a simple two-color selection

Using a simple two-color selection based on g-, z-, and K-band photometry, we choose from 1609 star-forming galaxies (sgzKs) and 422 passively evolving galaxies (pgzKs) at z ~ 2 from a K-band-selected sample (K AB < 22.0) in an area of ~0.44 deg2 of the All-wavelength Extended Groth Strip International Survey (AEGIS). The surface density of gzks is 1.28 arcmin-2 . For a simple selected at K < 22.0, we reach an average redshift accuracy of dz /(1+z) = -0.014 with the normalized median absolute deviation sigma = 0.031. The number counts of pgzks in our simple turn over at K = 21.0, and both the number of faint and bright objects in our catalogs exceed the predictions of a recent simi-analytic model of galaxy formation, a more successful model is need to explain thid diversity. Based on our reddening-corrected UV luminosities and SED fitting of the multiband photometry , we find the median values of star formation rate (SFR) and stellar mass of sgzKs corresponding to 184 Msun /yr and ~8.8 x 1010 Msun repectively. We also find that the specific star formation rate (sSFR) and SFR of sgzKs increases with redshift at all masses, implying that star-forming galaxies were much more active on average in the past. Moreover, the sSFR of massive galaxies in lower at all redshifts, suggesting that star formation contributes more to the mass growth of low-mass galaxies than to high-mass galaxies. Finally, We also study the the fraction of AGNs in the gzKs by using the IRAC band color criteria and the Mid-IR spectral in dex. 828 gzKs in our sample have four IRAC bands, 82 of which wuth alpha < -0.5 (using the power-law selection) can be classified as AGNs, so the fraction of AGNs is ~10% in our simple. Most of these AGN candidates have L 0.5-10kev > 1041 erg s-1.