Wednesday, November 11, 2009

Rapid Star Formation Spotted in Infant Galaxies


The Universe’s infant galaxies enjoyed rapid growth spurts forming stars like our sun at a rate of up to 50 stars a year, according to scientists at Durham University.

The findings show that “stellar nurseries” within the first galaxies gave birth to stars at a much more rapid rate than previously expected, the researchers from Durham’s Institute for Computational Cosmology revealed. Their work appears in a paper in the journal Monthly Notices of the Royal Astronomical Society.

The research looked back 12.5 billion years to one of the most distant known galaxies, seen as it appeared about one billion years after the Big Bang.

Using a technique called gravitational lensing – where distant galaxies are magnified using the gravity of a nearby galaxy cluster – the scientists observed the rapid bursts of star formation in the galaxy called MS1358arc.

Within the star-forming regions, new stars were being created at a rate of about 50 stars per year - around 100 times faster than had been previously thought.

The researchers, who say their work represents the most detailed study of a galaxy at such a young age, believe the observed galaxy is typical of others in the early Universe.

They say the galaxy, which measures 6,000 light years across, also has all the characteristics that would allow it to eventually evolve into a galaxy such as our Milky Way, giving an insight into how our sun and galaxy formed.

The Durham researchers based their findings on observations from the Gemini North telescope, based in Hawaii, and NASA’s Hubble and Spitzer Space Telescopes. The research was funded by the Royal Astronomical Society.

Lead author Dr Mark Swinbank, who is the Norman Lockyer Fellow of the Royal Astronomical Society and works in the Institute for Computational Cosmology, at Durham University, said: “The runaway effect in this galaxy suggests it is growing much faster than expected.

“Given the size of the star forming regions, we would expect it to be forming stars at the rate of about one sun per year, but it seems to be much more active than that.

“We think this galaxy is fairly typical of galaxies at this time and we expect that the Milky Way once looked like this as it formed its first stars.

“In effect we are seeing the first generation of stars being born in a galaxy like the Milky Way. This gives unique insight into the birth of our own galaxy.”

The researchers say most of the observed stars eventually exploded as supernovae, spewing debris back into space where it formed into new stars

Dr Swinbank added: “In this respect these stars are the seeds of future star formation in the Universe.”

Royal Astronomical Society President Professor Andy Fabian said: “It is exciting to see such a detailed picture of a very distant galaxy.

“This pioneering work shows what our own galaxy might have looked like when it was a tenth of its present age."

Forwarded from Durham University by:

Dr Robert Massey
Press and Policy Officer
Royal Astronomical Society
Tel: +44 (0)20 7734 3307
Mob: +44 (0)794 124 8035
E-mail: rm@ras.org.uk

CONTACTS

Dr Mark Swinbank
RAS Norman Lockyer Fellow
Institute for Computational Cosmology
Department of Physics
Durham University
Tel: +44 (0)191 334 3786
E-mail: a.m.swinbank@durham.ac.uk

Dr Swinbank is available for interview on Tuesday, November 10, and Wednesday, November 11.

Alternatively please contact

Durham University Media Relations Office
Tel: +44 (0)191 334 6075
E-mail: media.relations@durham.ac.uk

Note to broadcasters: An ISDN broadcast quality line is available via the Media Relations Office on the contact details above. The ISDN number is +44 (0)191 386 2749.

IMAGES

A 300dpi j-peg image showing the distant galaxy MS1358arc is available from Durham University Media Relations Office on request on +44 (0)191 334 6075 or e-mail media.relations@durham.ac.uk

Caption: A Hubble Space Telescope observation showing the red ‘arc’ of the rapid star forming galaxy MS1358arc – seen as it was 12.5 billion years ago. The galaxy is magnified by a factor of 10 by the younger foreground galaxies. (Credit: Dr Johan Richard, Durham University.)

Source Information:

A Spatially Resolved Map of the Kinematics, Star-Formation and Stellar Mass Assembly in a Star-Forming Galaxy at z=4.9, Swinbank, AM, et al, Monthly Notices of the Royal Astronomical Society, 2009, DOI (10.1111/j.1365-2966.2009.15617.x)

A PDF copy of the paper is available on request from Durham University Media Relations Office.

Institute for Computational Cosmology, Durham University: www.icc.dur.ac.uk/
Royal Astronomical Society: www.ras.org.uk/
Gemini Observatory: www.gemini.edu/
Spitzer Space Telescope: www.spitzer.caltech.edu/
Hubble Space Telescope: http://hubblesite.org/

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