| 摘 要： | Utilizing a Bz K-selection technique, we obtain 14 550 star-forming galaxies(sB z Ks) and 1763 passive galaxies(p Bz Ks) at z ～ 2 from the K-selected(KAB 22.5) catalog in the COSMOS/Ultra VISTA field. The differential number counts of sB z Ks and p Bz Ks are consistent with the results from the literature.Compared to the observed results, semi-analytic models of galaxy formation and evolution provide too few(many) galaxies at the high(low) mass end. Moreover, we find that the star formation rate and stellar mass of sB z Ks follow the relation of the main sequence. Based on HST/Wide Field Camera 3 F160 W imaging, we find a wide range of morphological diversities for sB z Ks, from diffuse to early-type spiral structures, with relatively high M20, large size and low G, while p Bz Ks have elliptical-like compact morphologies with lower M20, smaller size and higher G, indicating a more concentrated and symmetric spatial extent of stellar population distribution in p Bz Ks than sB z Ks. Furthermore, the sizes of p Bz Ks(sB z Ks) at z ～ 2 are on average two to three(one to two) times smaller than those of local early-type(late-type) galaxies with similar stellar mass. Our findings imply that the two classes have different evolution models and mass assembly histories.
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