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Subaru Reveals Galaxy Formation From 11 Billion Years Ago
Hilo HI (SPX) Dec 18, 2007 A team of Japanese astronomers have obtained imagees of galaxies from 11 billion years ago using innovative technology and instrumentation on the Subaru Telescope. The images of the distant galaxies show almost all of the galaxies have a light profile similar to the disk galaxies in the local universe around our Milky Way galaxy, indicating that a majority of galactic formation occurred earlier than previously estimated. As background, in the local universe around our Milky Way galaxy, there are primarily two types of galaxies: elliptical and disk. Elliptical galaxies have stars that cluster in shapes ranging from nearly spherical to highly elongated, and disk galaxies have stars that make a spiral structure on a flattened disk shape (sometimes called "spiral galaxies"). When, why, and how these galaxies in the local universe establish their current shapes are some of the biggest mysteries in astronomy. In order to answer these questions, it is important to observe galaxies as far away as possible, going back in time, tracing their cosmic history, examining their shapes and forms to determine their evolutionary profile. In 2004, Japanese astronomers from the National Astronomical Observatory of Japan (NAOJ), Tokyo University, and Kyoto University in Japan used the adaptive optics (AO) system and the infrared camera and spectrograph (IRCS) instrument on the Subaru Telescope to obtain deep field and high-resolution images of galaxies from 11 billion years ago, further than previously observed. Their research was based on knowledge that galaxies consist of stars with various masses, sizes, and ages, and because the shapes of galaxies reflect their distribution of stars, astronomers think the shapes represent the "framework" of the galaxies. The preliminary results show the light distributions of the very distant galaxies have similar light profiles to the flatter disk galaxies in the local universe. Considering the two types of galaxies seen in the local universe already exist in the universe 8 billion years ago, the initial findings showed that concentrated elliptical galaxies formed from the collision and merging of extended disk galaxies between 11 billion and 8 billion years ago. Dr. Masayuki Akiyama of Subaru Telescope, Principal Investigator for the project, reports that "we have not been sure when the shapes of galaxies currently seen in the local universe appear, but the result indicates that radical changes of the shapes of galaxies happened between 8 and 11 billion years ago". The profiles of the galaxies further away infer that the evolution of the galaxies is much milder between the present and 8 billion years ago than between 11 and 8 billion years ago. In the future, Dr. Akiyama hopes to do larger observations of galaxies away from local bright stars using the recently upgraded AO system with artificial laser guide star at the Subaru Telescope. Community Email This Article Comment On This Article Related Links Subaru Telescope Stellar Chemistry, The Universe And All Within It
Solving A Solar System Quandary By Flip-Flopping Uranus And Neptune
Tempe AZ (SPX) Dec 13, 2007Quick: What's the order of the planets in the solar system? Need a little help? Maybe the following mnemonic rings a bell: "My Very Educated Mother Just Served Up Nine Pizzas." It's useful for remembering the order of the planets today, but it wouldn't have been as useful in the past, and not just because the International Astronomical Union demoted Pluto to "dwarf planet" last year. |
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