Subscribe free to our newsletters via your
. 24/7 Space News .

Candels Team Discovers Dusty Galaxies At Ancient Epoch With Hubble Space Telescope
by Staff Writers
Austin TX (SPX) Oct 10, 2012

illustration only

Dust is an annoyance in everyday life, but an important building block of stars and planets. As such, astronomers need to understand how cosmic dust forms over time - it's an integral step in figuring out the evolution of galaxies, and the stars and planets within them.

To better understand cosmic dust, University of Texas at Austin assistant professor Steven Finkelstein and colleagues are pursuing one of the largest Hubble Space Telescope projects to date, studying dust in thousands of galaxies over a wide range of cosmic time. They published some early results in a paper led by Finkelstein in a recent issue of The Astrophysical Journal [].

"We don't yet understand how galaxies build up their dust reservoirs," Finkelstein said. "We know that dust builds up through time, but exactly when the formation of dust begins is unknown."

Finkelstein is part of a large team of astronomers working to rectify that knowledge gap. They are studying nearly 3,000 galaxies seen 500 million to 1,500 million years after the Big Bang - only a moment after the initial event, when compared to the 13.7-billion-year age of the universe. The project is called CANDELS: the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey.

Some of the galaxies came from the team's own ongoing Hubble observations: more than 900 orbits studying distant galaxies with the Wide Field Camera 3 (WFC3). They also include data from several other large Hubble galaxy surveys (including Great Observatories Origins Deep Survey (GOODS) and the Hubble Ultra-Deep Field survey).

Finkelstein said that previous studies with smaller surveys, including some of his own, appeared to indicate that ancient galaxies were dust free. But CANDELS has found that even at a very early epoch, massive galaxies already contain a lot of dust, in the form of grains of carbon and silicon (in astronomical jargon, "heavy metals").

"We found something we wouldn't expect," Finkelstein said. "Although dust can form quickly, I don't think many people expected galaxies at only 800 million years after the Big Bang to have a lot of dust. These observations caused us to change our thinking."

Studying such ancient, and thus faint, galaxies is tricky even for Hubble. Only a miniscule amount of information comes through in the tiny stream of photons they send our way, but their color can be determined. This was the team's quarry. Galaxy colors are a clue to the amount of dust a galaxy contains: The redder a galaxy appears, the more dust it contains. The bluer it appears, the less dust it contains.

And finding a significant amount of "heavy metal" dust in these early massive galaxies means they must have been forming stars for a while, Finkelstein said. That's because heavy elements were not created in the Big Bang itself. They are built up over time inside stars, as they fuse lighter elements into heavier ones through nuclear fusion at their cores. When a massive star runs through all of this nuclear fuel, it explodes as a spectacular supernova, spewing these heavy elements into the galaxy. These heavy elements are the building blocks for the dust for which CANDELS was looking.

"These results are very interesting because they tell us that dust does form at early times," he said. "This is important because the same elements that compose the dust grains are necessary for the formation of planets. Also, we think that dust is a key component in allowing hydrogen gas to form molecules, which is necessary for star formation."

Additionally, the team found that in between 800 million and 1.5 billion years after the Big Bang, "all galaxies - not just massive ones - get dusty," Finkelstein said.

This work has him excited about the future, Finkelstein said. "The presence of dust means that a previous generation of stars has lived and died. So, when we can peer back to even farther later this decade with JWST [the James Webb Space Telescope], there should be a lot for us to see!"


Related Links
McDonald Observatory
Astronomy Program at UT Austin
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Large water reservoirs at the dawn of stellar birth
Paris, France (ESA) Oct 10, 2012
ESA's Herschel space observatory has discovered enough water vapour to fill Earth's oceans more than 2000 times over, in a gas and dust cloud that is on the verge of collapsing into a new Sun-like star. Stars form within cold, dark clouds of gas and dust - 'pre-stellar cores' - that contain all the ingredients to make solar systems like our own. Water, essential to life on Earth, has ... read more

China has no timetable for manned moon landing

Senior scientist discusses China's lunar orbiter challenges

NASA sees 'gateway' for space missions

Protection for Moon, Mars astronauts eyed

First Scoopful A Success

Checking a Bright Object on the Ground

China to collect samples from Mars by 2030: Xinhua

Mars rover finds 'bright object'

Dead stars could be cosmic 'GPS'

Dead stars could be the future of spacecraft navigation

Interstellar Travelers of the Future May be Helped by MU Physicist's Calculations

Singer Sarah Brightman to become space tourist

ChangE-2 Mission To Lagrange L2 Point

Meeting of heads of ESA and China Manned Space Agency

China Spacesat gets 18-million-USD gov't support

Tiangong Orbit Change Signals Likely Date for Shenzhou 10

NASA and International Partners Approve Year Long ISS Stay

Year on ISS planned ahead of manned Mars mission

NASA Celebrates Milestone Liftoff

45th Space Wing Supports First SpaceX Launch for NASA's Commercial Resupply Services

SpaceX capsule links up with space station: NASA

Assembled and poised for launch: Soyuz is ready with its two Galileo navigation satellites

SpaceX On Course For Crew Resupply Cargo Delivery To Space Station

SpaceX craft on way to ISS in first supply run

Candels Team Discovers Dusty Galaxies At Ancient Epoch With Hubble Space Telescope

Large water reservoirs at the dawn of stellar birth

Comet crystals found in a nearby planetary system

The Magnetic Wakes of Pulsar Planets

Court delays Australian miner's Malaysia plant

Making computer data storage cheaper and easier

Architect shares simple green architecture improvements for homes and offices

An operating system in the cloud

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement