Color gradients of the galaxies at 0.5

We investigate the color gradients of galaxies at 0.5 < z < 1.0, using a sample of ~35 000 galaxies with both spectroscopy from the final data release of the VIMOS Public Extragalactic Redshift Survey(VIPERS), and photometry in ultraviolet/optical/near-infrared bands from the VIPERS-MultiLambda Survey(VIPERS-MLS) and the Canada-France-Hawaii Telescope Legacy Survey(CFHTLS).We estimate rest-frame colors, stellar mass, star formation rate from fitting the Spectral Energy Distribution(SED) for each galaxy, as well as a two-zone color ?(u-r), defined as the difference in rest-frame(u-r) color between the outer and inner region of the galaxy. We find that the two-zone color shows weak or no correlations with all galaxy properties considered except stellar mass. On average, ?(u-r) decreases with increasing stellar mass, indicating relatively red colors in galactic centers of more massive galaxies. We then compare the properties of "red-cored" and "blue-cored" galaxies,defined to have either a negative or a positive ?(u-r) respectively. Although the two types of galaxies show similar distributions in most properties, we find massive red-cored galaxies with M*> 1010.5M⊙to have larger sizes at given stellar mass(thus lower surface mass densities), and less massive red-cored galaxies with M*< 1010.5M⊙to have lower central galaxy fraction. These findings can be understood if one assumes that the star formation process happens from inside out, in the same way as recently emphasized in studies of low-z galaxies. The similarity between the galaxies at intermediate redshifts and those at low redshifts supports the idea that galaxy evolution since z~1 has been mainly driven by secular processes internal to galaxies rather than galaxy mergers or external environment.

Color gradients of the galaxies at 0.5

We investigate the dependence of clustering on luminosity, stellar mass and color gradient for galaxies at 0.5 < z < 1, using a sample of;300 galaxies from the final data release of the VIMOS Public Extragalactic Redshift Survey（VIPERS-PDR2）. We estimate both the auto-correlation function for galaxy samples selected by B-band absolute magnitude and stellar mass, and the cross-correlation function of galaxy samples selected by color gradient with respect to the full galaxy sample. The autocorrelation function amplitudes at fixed scale are found to positively correlate with both galaxy luminosity and stellar mass, and the effect holds for all the scales probed(0.2 h;Mpc < rp< 20 h;Mpc),in good agreement with previous measurements based on an earlier data release of VIPERS. When the stellar mass is limited to a narrow range, we find the clustering power to be essentially independent of galaxy color gradient, and this conclusion is true for all the masses and all the scales considered here. In a parallel paper, we find that the half-light radius is the only galaxy property other than stellar mass that is related to color gradient. Considering the previous finding that clustering depends weakly on galaxy structure at given mass, the non-dependence of clustering on color gradient found here reinforces our conclusion that the color gradient and structural parameters of a galaxy are intrinsically related to each other.