The Hubble data are from proposal: 11683 M. Sun (University of Alabama, Huntsville), M. Donahue and M. Voit (Michigan State University), and C. Jones and W. Forman (Smithsonian Institution Astrophysical Observatory).
ACS/WFC: F475W (g) and F814W (I)
WFC3/UVIS: F275W (U)
This composite image includes exposures acquired by the ACS and WFC3 instruments on the Hubble Space Telescope. Several filters were used to sample broad wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are:
Lt blue: F275W (U)
Cyan: F475W (g)
Orange: F814W (I)