Free Astronomy Magazine May-June 2016

32 SPACE CHRONICLES Telescopes combine to push frontier on galaxy clusters by NASA M ACS J0416.1-2403. [NASA, ESA, CXC, NRAO/AUI/NSF, STScI, and G. Ogrean (Stanford University)] T o learn more about galaxy clusters, including how they grow via collisions, astrono- mers have used some of the world's most powerful telescopes, looking at different types of light. They have focused long observations with these telescopes on a half-doz- en galaxy clusters. The name for the galaxy cluster project is the "Fron- tier Fields." Two of these Frontier Fields galaxy clusters, MACS J0416.1- 2403 (abbreviated MACS J0416), above, and MACS J0717.5+3745 (MACS J0717 for short), in the next page, are featured here in a pair of multiwavelength images. Located about 4.3 billion light-years from Earth, MACS J0416 is a pair of colliding galaxy clusters that will eventually combine to form an even