Herschel looks back in time to see today's stars bursting into life

Dec 17, 2010
An artist's rendition of one of the newly discovered SPIRE 'hot starburst' galaxies (credit: NASA/CXC/M.Weiss)

(PhysOrg.com) -- An international team of astronomers have presented the first conclusive evidence for a dramatic surge in star birth in a recently discovered population of massive galaxies in the early Universe.

The scientists used the European Space Agency's Herschel , an with a mirror 3.5 m in diameter, launched in 2009. They studied the distant objects in detail with the Spectral and Photometric Imaging Receiver (SPIRE) camera, obtaining solid evidence that the galaxies are forming stars at a tremendous rate and have large reservoirs of gas that will power the for hundreds of millions of years.

Dr Scott Chapman from the Institute of Astronomy at the University of Cambridge, presents the new results in a paper in a special edition of the journal Monthly Notices of the Royal Astronomical Society focusing on results from Herschel.

"These Herschel-SPIRE measurements have revealed that a population of galaxies is hotter than expected, due to forming stars far more rapidly than we previously believed," he said.

The key to the new results is the recent discovery of a new type of extremely luminous galaxy in the early Universe. These galaxies are very faint in visible light, as the newly-formed stars are still cocooned in the clouds of of gas and dust within which they were born. This cosmic dust, which sits at around -232 C, is much brighter at the longer, far infrared wavelengths observed by the Herschel satellite.

A related type of galaxy was first found in 1997 (but not well understood until 2003) using the "SCUBA" camera attached to the James Clerk Maxwell Telescope on Hawaii, which detects radiation emitted at even longer sub-millimetre wavelengths. But these distant "sub-millimetre galaxies" were thought to only represent half the picture of star formation in the early Universe. Since SCUBA preferentially detects colder objects, it was suggested that similar galaxies with slightly warmer temperatures could exist but have gone largely unnoticed.

Dr. Chapman and others measured their distances using the Keck optical telescope on Hawaii and the Plateau de Bure sub-millimetre observatory in France, but were unable to show that they were in the throes of rapid star formation.

Herschel would be the first telescope with the capability to detect these galaxies at the peak of their output, so Dr. Chapman joined forces with the "HerMES" team, led by Professor Seb Oliver of the University of Sussex and Dr Jamie Bock in the Jet Propulsion Laboratory California, who were undertaking the largest survey of galaxies with Herschel.

With the Herschel observations, focused on around 70 galaxies in the constellation of Ursa Major the scientists acquired the missing piece of evidence to confirm that these galaxies represent a crucial episode in the build up of large galaxies around us today, such as our own Milky Way.

Team member Professor Rob Ivison from the University of Edinburgh said: "With the data we had before, we couldn't tell exactly where the infrared light from these galaxies comes from. But using SPIRE we can see that this is the signature of star formation."

The new galaxies have prodigious rates of star formation, far higher than anything seen in the present-day Universe. They probably developed through violent encounters between hitherto undisturbed galaxies, after the first stars and galaxy fragments had already formed. None the less, studying these new objects gives an insight into early epochs of star formation after the Big Bang.

Team colleague Dr Isaac Roseboom from the University of Sussex said: "It was amazing and surprising to see the Herschel-SPIRE observations uncover such a dramatic population of previously unseen galaxies." Professor Seb Oliver, also from Sussex, added: "We are really blown away by the tremendous capability of to probe the distant universe. This work gives us a real handle on how the cosmos looked early in its life."

With the new discovery, the UK-led astronomers have provided a much more accurate census of some of the most extreme  in the Universe at the peak of their activity. Future observations will investigate the details of the galaxies' power source and try to establish how they will develop once their intense bursts of activity come to an end.

Explore further: Astronomer confirms a new "Super-Earth" planet

Related Stories

Astronomers find evidence of cosmic climate change

Nov 02, 2010

(PhysOrg.com) -- Evidence of an intense warming period in the Universe’s early history, described as a form of "cosmic climate change", has been found by an international team of astronomers.

Herschel reveals details of distant galaxies and quasars

Jul 01, 2010

(PhysOrg.com) -- Amazing new data captured by ESA's (European Space Agency) Herschel Space Observatory - carrying the largest mirror ever launched into space - have just been publicly released, allowing the ...

Bright galaxies like to stick together

May 26, 2010

(PhysOrg.com) -- Astronomers using the European Space Agency's Herschel telescope have discovered that the brightest galaxies tend to be in the busiest parts of the Universe. This crucial piece of information ...

Lensed galaxies

Nov 12, 2010

In 1915, Einstein amazed the world by predicting that the path of light could be bent by mass. As a consequence, light from a distant galaxy passing by an intervening galaxy en route to earth will be distorted. ...

Recommended for you

Image: Multicoloured view of supernova remnant

4 hours ago

Most celestial events unfold over thousands of years or more, making it impossible to follow their evolution on human timescales. Supernovas are notable exceptions, the powerful stellar explosions that make ...

Ultra-luminous X-ray sources in starburst galaxies

4 hours ago

Ultra-luminous X-ray sources (ULXs) are point sources in the sky that are so bright in X-rays that each emits more radiation than a million suns emit at all wavelengths. ULXs are rare. Most galaxies (including ...

When a bright light fades

4 hours ago

Astronomer Charles Telesco is primarily interested in the creation of planets and stars. So, when the University of Florida's giant telescope was pointed at a star undergoing a magnificent and explosive death, ...

Image: Horsehead nebula viewed in infrared

5 hours ago

Sometimes a horse of a different color hardly seems to be a horse at all, as, for example, in this newly released image from NASA's Spitzer Space Telescope. The famous Horsehead nebula makes a ghostly appearance ...

The Milky Way's new neighbour

5 hours ago

The Milky Way, the galaxy we live in, is part of a cluster of more than 50 galaxies that make up the 'Local Group', a collection that includes the famous Andromeda galaxy and many other far smaller objects. ...

Image: Hubble sweeps a messy star factory

5 hours ago

This sprinkle of cosmic glitter is a blue compact dwarf galaxy known as Markarian 209. Galaxies of this type are blue-hued, compact in size, gas-rich, and low in heavy elements. They are often used by astronomers ...

User comments : 4

Adjust slider to filter visible comments by rank

Display comments: newest first

lengould100
5 / 5 (5) Dec 17, 2010
It really is impressive to think that an essentially inconsequential organism which developed on a presumeably relatively common planet in a non-descript suburb of a very average spiral galaxy could produce the sorts of astronomic observations we do.
Husky
4 / 5 (3) Dec 17, 2010
it only took us a few hundred million years to evolve to that point ;-)Given the recent discovery that our universe could host up to 30 percent more, red dwarf stars, that got unnoticed due to their smaller size, temperature and being more obscured by dust, it all adds to the importance of looking at the full infrared spectrum to paint a complete picture.
kevinrtrs
1.9 / 5 (8) Dec 17, 2010
Unfortunately the article is somewhat fuzzy on exactly what was observed and how exactly those observations were interpreted.

One thing is clear though: Big bang seems to be in for another hit:
measurements have revealed that a population of galaxies is hotter than expected, due to forming stars far more rapidly than we previously believed, he said.

Seems like stars don't take millions of years to form, they might well be born in the blink of an eye. We'll see what comes up next.
geokstr
4 / 5 (4) Dec 17, 2010
The new galaxies have prodigious rates of star formation, far higher than anything seen in the present-day Universe.

It only makes sense that back in the time when the universe was much smaller and the only things out there were gas and dust clouds, that there must have been a time when stars started forming at the rate of microwave popcorn, literally. It's only once most of that material is already bound up in stars and far more spread out that the rate of star formation would slow to the present pace.
it only took us a few hundred million years to evolve to that point ;-)

But it's only in the last few decades that we've had the technology to do what we are now. The only reason I regret being a seasoned citizen is that I will not be around to see all the marvels and wonders we discover in the next fifty years. (That is of course unless we manage to extinct ourselves first.)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.