An example of galaxy that shows a double-component structure in the HST/ACS image. North is up and east is left. Each panel has a size of 4" x 4", which corresponds to 85 kly x 85 kly at the distance of 12.6 billion light-years. The thumbnails of the HST/ACS I band (effective wavelength = 814 nm), the Subaru Telescope/Suprime-Cam NB711 and i'- and z'-bands are shown from left to right. Note that the NB711 image, which captures the Lyman-alpha line emitted by neutral hydrogen, shows spatially extended gas which is ionized by ultraviolet (UV) radiation from many massive stars. On the other hand, other band images prove the UV radiation from massive stars themselves.