A European Southern Observatory image of the barred spiral galaxy NGC 1365, rotated to match the orientation of the first image. NGC 1365 is about 56 million light years away, so we see it as it appears 56 million years ago, or 10 billion years later than the galaxy in the HST image. Credit: ESO/IDA/Danish 1.5 m/ R. Gendler, J-E. Ovaldsen, C. Thöne, and C. Feron.
Astronomers have long sought to understand exactly how the universe
evolved from its earliest history to the cosmos we see around us in the
present day. In particular, the way that galaxies form and develop is
still a matter for debate. Now a group of researchers have used the
collective efforts of the hundreds of thousands of people that volunteer
for the Galaxy Zoo project to
shed some light on this problem. They find that galaxies may have
settled into their current form some two billion years earlier than
previously thought.
Dr Brooke Simmons of the University of Oxford and her collaborators describe the work in a paper in Monthly Notices of the Royal Astronomical Society. The team set Zoo volunteers the task of classifying the shapes of tens of thousands of galaxies observed by the Hubble Space Telescope.
These objects are typically very distant, so we see them as they
appeared more than 10 billion years ago, when the universe was about 3
billion years old, less than a quarter of its present age.
The newly classified galaxies are striking in that they look a lot
like those in today’s universe, with disks, bars and spiral arms. But
theorists predict that these should have taken another 2 billion years
to begin to form, so things seem to have been settling down a lot
earlier than expected.
Brooke comments: “When we started looking for these galaxies, we
didn't really know what we'd find. We had predictions from galaxy
simulations that we shouldn't find any of the barred features that we
see in nearby, evolved galaxies, because very young galaxies might be
too agitated for them to form.”
‘But we now know that isn't the case. With the public helping us
search through many thousands of images of distant galaxies, we
discovered that some galaxies settle very early on in the Universe.”
Media contact
Dr Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7734 3307 / 4582
Mob: +44 (0)794 124 8035
rm@ras.org.uk
Science contact
Dr Brooke Simmons
University of Oxford
Tel: +44 (0)1865 273637
brooke.simmons@astro.ox.ac.uk
Further information
The new work appears in “Galaxy Zoo: CANDELS Barred Disks and Bar Fractions”, B. D. Simmons et al, Monthly Notices of the Royal Astronomical Society, Oxford University Press, 445, pp. 3466-3474.
A preprint of the paper is available on the arXivv
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