Feeds

Finding missing galaxies: Spitzer triumphs again

No word on how they were lost

Build a business case: developing custom apps

NASA's Spitzer observatory has logged more than 1,000 previously unknown dwarf galaxies hiding out in a giant cluster of galaxies.

Using data from the infrared observatory, a team led by Leigh Jenkins and Ann Hornschemeier, both at NASA Space Flight Centre, was able to resolve many galaxies that are too faint for other telescopes to see.

Dwarf galaxies are thought to be the earliest stage of galactic evolution, and provide the building blocks for larger galaxies. Researchers also use them as tracers to track the larger scale structure of the universe.

The Coma cluster

But for all their usefulness, they have been remarkably thin on the ground. Simulations suggest we should find more of them in giant clusters, like the coma cluster, than have been seen to date.

The coma cluster, as it is known, lies 320 million light years away in the (surprise!) constellation Coma. It spans a volume approximately 20 million light years across, and holds hundreds of galaxies that have already been studied.

As a giant cluster it should be positively brimming with dwarf galaxies. And it seems it is. Of 30,000 objects logged by the research team, 1,200 were found (on closer examination) to be dwarf galaxies. Scaling up to take in the whole cluster, this implies at least 4,000 dwarf galaxies.

The team had initially thought that some of the fainter objects would be background galaxies even further away. But secondary data from the William Herschel telescope settled it: the faint smudges were small galaxies - with masses comparable to, or even smaller than, that of the Small Magellanic Cloud, one of the Milky Way's satellite galaxies.

"With Spitzer's superb capabilities, we have suddenly been able to detect thousands of faint galaxies that weren't seen before," says Jenkins.

"We're blowing away previous infrared surveys of nearby clusters," Hornschemeier notes. "Thanks to Spitzer, we can observe nearby clusters such as Coma very deeply in a short amount of time. The total observing time is comparable to just a few nights at a ground-based observatory."

The research is being presented at the American Astronomical Society meeting in Hawaii. The discovery paper will also appear in the Astrophysical Journal, NASA says. ®

The Essential Guide to IT Transformation

More from The Register

next story
Just TWO climate committee MPs contradict IPCC: The two with SCIENCE degrees
'Greenhouse effect is real, but as for the rest of it ...'
Asteroid's DINO KILLING SPREE just bad luck – boffins
Sauricide WASN'T inevitable, reckon scientists
Flamewars in SPAAACE: cooler fires hint at energy efficiency
Experiment aboard ISS shows we should all chill out for cleaner engines
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
NASA Mars rover FINALLY equals 1973 Soviet benchmark
Yet to surpass ancient Greek one, however
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
BEST BATTERY EVER: All lithium, all the time, plus a dash of carbon nano-stuff
We have found the Holy Grail (of batteries) - boffins
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Backing up Big Data
Solving backup challenges and “protect everything from everywhere,” as we move into the era of big data management and the adoption of BYOD.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.