The ACS data was from the HST proposal 10584: A. Zezas, G. Fabbiano, A. Prestwich, and M. Garcia (Harvard-Smithsonian Center for Astrophysics), J. Gallagher (University of Wisconsin, Madison), J. Miller (University of Michigan), P. Kaaret (University of Iowa), V. Kalogera (Northwestern University), M. Ward (University of Durham), and A. King (University of Leicester); and proposal 10250: J. Huchra, P. Barmby, and B. Mcleod (Harvard-Smithsonian Center for Astrophysics) and J. Brodie and J. Strader (University of California, Santa Cruz).
This image is a composite of many separate exposures made by the ACS instrument on the Hubble Space Telescope. Three filters were used to sample light from broad wavelengths. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are:
