Keywords: A520 comp.jpg en Abell 520 Train Wreck cluster composite view Chandra X-ray observatory site Harvard University a520_comp jpg JPEG Image 792x600 pixels - Scaled 89 http //chandra harvard edu/photo/2007/a520/a520_comp jpg NASA 2007-04 PD-USGov wrong-license This is not solely NASA data and CFHT is not public domain Abell 520 Chandra images |