Images of 11 billion year-old galaxies suggest galactic formation occurred earlier than believed

December 18th, 2007 - 7:26 pm ICT by admin  

Washington, Dec 18 (ANI): A team of Japanese astronomers has obtained images of galaxies dating 11 billion years, which indicates that a majority of galactic formation occurred earlier than previously estimated.
The images have been captured using innovative technology and instrumentation on the Subaru Telescope by astronomers from the National Astronomical Observatory of Japan (NAOJ).
The Subaru Telescope obtained 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.
“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,” said Dr. Masayuki Akiyama of Subaru Telescope, Principal Investigator for the project.
The local universe in the Milky Way Galaxy has 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. (ANI)

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