Mysteries of "The Redshift Desert" --Why Do Galaxies in the Early Universe Appear Old? [View all]

[n2doc]

Some of the faintest spectra in the universe raise a glaring question: Why do Galaxies in the early universe appear old? Until recently, astronomers have been nearly blind when looking back in time to survey an era when most stars in the Universe were expected to have formed. This critical cosmological blind-spot was removed in 2011 by a team using the Frederick C. Gillett Gemini North Telescope located on Mauna Kea, Hawaii, showing that many galaxies in the young Universe are not behaving as they would have expected some 8-11 billion years ago.
The surprise: these galaxies appear to be more fully formed and mature than expected at this early stage in the evolution of the Universe.
"Theory tells us that this epoch should be dominated by little galaxies crashing together," said Dr. Roberto Abraham (University of Toronto) who was a Co-Principal Investigator of the team that conducted the observations at Gemini. "We are seeing that a large fraction of the stars in the Universe are already in place when the Universe was quite young, which should not be the case. This glimpse back in time shows pretty clearly that we need to re-think what happened during this early epoch in galactic evolution. The theoreticians will definitely have something to gnaw on!"
These observations are from a multinational investigation, called the Gemini Deep Deep Survey (GDDS), which used a special technique to capture the faintest galactic light ever dissected into the rainbow of colors called a spectrum. In all, spectra from over 300 galaxies were collected, most of which are within what is called the "Redshift Desert," a relatively unexplored period of the Universe seen by telescopes looking back to an era when the universe was only 3-6 billion years old.

http://www.dailygalaxy.com/my_weblog/2012/03/mystery-of-the-redshift-desert-why-do-galaxies-in-the-early-universe-appear-old.html