Studying the evolution and anatomy of galaxies using the Hubble Space Telescope, an international team of astronomers led by doctoral candidate BoMee Lee and her advisor Mauro Giavalisco at the University of Massachusetts Amherst have established that mature-looking galaxies existed much earlier than previously known, when the universe was only about 2.5 billion years old, or 11.5 billion years ago.”Finding them this far back in time is a significant discovery,” says lead author Lee.
The team used two cameras, Wide Field Camera 3 (WFC3), and Advanced Camera for Surveys (ACS), plus observations from the Hubble’s Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), the largest project in the scope’s history with 902 assigned orbits of observing time, to explore the shapes and colors of distant galaxies over the last 80 percent of the Universe’s history. Results appear in the current online issue of The Astrophysical Journal.
Lee points out that the huge CANDELS dataset allowed her team to analyze a larger number of these galaxies, a total 1,671, than ever before, consistently and in detail. “The significant resolution and sensitivity of WFC3 was a great resource for us to use in order to consistently study ancient galaxies in the early Universe,” says Lee.
She and colleagues confirm for an earlier period than ever before that the shapes and colors of these extremely distant young galaxies fit the visual classification system introduced in 1926 by Edwin Hubble and known as the Hubble Sequence. It classifies galaxies into two main groups: Ellipticals and spirals, with lenticular galaxies as a transitional group. The system is based on their ability to form stars, which in turn determines their colors, shape and size.
Read more at: Phys.org