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Register a new userThe mass dependence of structure, star formation rate, and mass assembly mode at 0.5<z< 2.5
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Yizhou Gu
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To investigate the mass dependence of structural transformation and star formation quenching, we construct three galaxy samples using massive ($M_* > 10^{10} M_{odot}$) red, green, and blue galaxy populations at $0.5<z<2.5$ in five 3D--{it HST}/CANDELS fields. The structural parameters, including effective radius ($r_{rm e}$), galaxy compactness ($Sigma_{1.5}$), and second order moment of 20% brightest pixels ($M_{20}$) are found to be correlated with stellar mass. S{e}rsic index ($n$), concentration ($C$), and Gini coefficient ($G$) seem to be insensitive to stellar mass. The morphological distinction between blue and red galaxies is found at a fixed mass bin, suggesting that quenching processes should be accompanied with transformations of galaxy structure and morphology. Except for $r_e$ and $Sigma_{1.5}$ at high mass end, structural parameters of green galaxies are intermediate between red and blue galaxies in each stellar mass bin at $z < 2$, indicating green galaxies are at a transitional phase when blue galaxies are being quenched into quiescent statuses. The similar sizes and compactness for the blue and green galaxies at high-mass end implies that these galaxies will not appear to be significantly shrunk until they are completely quenched into red QGs. For the green galaxies at $0.5<z<1.5$, a morphological transformation sequence of bulge buildup can be seen as they are gradually shut down their star formation activities, while a faster morphological transformation is verified for the green galaxies at $1.5<z<2.5$.
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