Washington DC: Thanks to a new, large-scale computer simulation, scientist now have theoretical evidence that large disk galaxies, similar to Milky Way, may have existed in the early days of the universe.
Created by physicists at Carnegie Mellon University's McWilliams Center for Cosmology and the University of California Berkeley, the simulation shows that the early universe-a mere 500 million years after the Big Bang-might have had more order and structure than previously thought.
Their findings will help guide researchers using next-generation telescopes like the Wide Field Infrared Survey Telescope (WFIRST) and the James Webb Space Telescope (JWST) as they search the sky for evidence of the first galaxies.
Professor Tiziana Di Matteo said that it was awe inspiring to think that galaxies much like our own existed when the universe was so young. The deepest Hubble Space Telescope observations have thus only covered small volumes of space and have found very irregular, clumpy galaxies at these early epochs. It is not surprising that in these small volumes some of the small galaxies do not have regular morphologies like large disk galaxies. Similarly, numerical simulations have been limited in size so they have only made predictions for the smaller, clumpier galaxies at these early times.
After the simulation was completed, the researchers looked at their data to see what they could find, much like observational cosmologists would do with data gathered using a telescope. They were surprised to find a number of disk galaxies in the universe at 500 million years post-Big Bang. Since disk galaxies are so large and complex, most researchers assumed that they would take a very long time to form and would be rare, if they existed at all, in the early universe.
Scientists said that their simulation showed that the early universe might be far from being just this. It might contain beautiful symmetrical galaxies, like the Milky Way.
The findings are due to be published in The Astrophysical Journal Letters.
