Ultradiffuse galaxies in HFF massive clusters

Our best-fitting GALFIT models show that the HFF UDGs have a median Sersic index of 1.09, which is close to 0.86 for local UDGs in the Coma cluster. The median axis-ratio value is 0.68 for HFF UDGs and 0.74 for Coma UDGs, respectively.

The structural similarity between HFF and Coma UDGs suggests that they are the same kind of galaxies seen at different times, and that the structures of UDGs do not change at least for several billion years. By checking the distribution of HFF UDGs in the rest-frame UVJ and UVI diagrams, we find a large fraction of them are star forming. Furthermore, a majority of HFF UDGs show small U-V color gradients within the 1*R_e,SMA_ region, and the fluctuation of the median radial color profile of HFF UDGs is smaller than 0.1mag, which is compatible to Coma UDGs.