Feeds

Finding missing galaxies: Spitzer triumphs again

No word on how they were lost

The Power of One Infographic

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. ®

Eight steps to building an HP BladeSystem

More from The Register

next story
Malaysian Airlines flight MH17 claimed lives of HIV/AIDS cure scientists
Researchers, advocates, health workers among those on shot-down plane
Forty-five years ago: FOOTPRINTS FOUND ON MOON
NASA won't be back any time soon, sadly
Mwa-ha-ha-ha! Eccentric billionaire Musk gets his PRIVATE SPACEPORT
In the Lone Star State, perhaps appropriately enough
MARS NEEDS OCEANS to support life - and so do exoplanets
Just being in the Goldilocks zone doesn't mean there'll be anyone to eat the porridge
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Diary note: Pluto's close-up is a year from … now!
New Horizons is less than a year from the dwarf planet
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?
prev story

Whitepapers

Reducing security risks from open source software
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
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.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.