Free Astronomy Magazine March-April 2016

SPACE CHRONICLES A stronomers have made the most detailed study yet of an extremely mas- sive young galaxy cluster using three of NASA's Great Observatories. This multiwavelength image shows this galaxy cluster, called IDCS J1426.5+3508 (IDCS J1426 for short), in X-rays, blue, visible light, green, infrared and red light from Chandra X-ray Observatory, Hubble Space Telescope and Spitzer Space Telescope. [NASA, ESA, and M. Brodwin (University of Missouri)] NASA's observatories weigh massive young galaxy cluster by NASA A stronomers have used data from three of NASA's Great Observatories to make the most detailed study yet of an extre- mely massive young galaxy cluster. This rare galaxy cluster, which is located 10 billion light-years from Earth, is almost as massive as 500 tril- lion suns. This object has important implications for understanding how these megastructures formed and evolved early in the universe. The galaxy cluster, called IDCS J1426.5 +3508 (IDCS J1426 for short), is so far away that the light detected is from when the universe was roughly a quarter of its current age. It is the most massive galaxy cluster detected at such an early age. First discover- ed by the Spitzer Space Telescope in 2012, IDCS J1426 was then observed using the Hubble Space Telescope and the Keck Observatory to determine its distance. Observations from the Com- bined Array for Millimeter-wave As- tronomy indicated it was extremely massive. New data from the Chandra X-ray Observatory confirm the gal- axy cluster mass and show that about 90 percent of the mass of the cluster is in the form of dark matter, a myste- rious substance detected so far only through its gravitational pull on nor- mal matter composed of atoms. "We are really pushing the boundaries with this discovery," said Mark Brod-