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Archive for March 14, 2012

Getting a Full Picture of an Elusive Subject

March 14, 2012 Leave a comment

Two teams of astronomers have used data from NASA’s Chandra X-ray Observatory and other telescopes to map the distribution of dark matter in a galaxy cluster known as Abell 383, which is located about 2.3 billion light years from Earth. Not only were the researchers able to find where the dark matter lies in the two dimensions across the sky, they were also able to determine how the dark matter is distributed along the line of sight.

Dark matter is invisible material that does not emit or absorb any type of light, but is detectable through its gravitational effects. Several lines of evidence indicate that there is about six times as much dark matter as “normal,” or baryonic, matter in the Universe. Understanding the nature of this mysterious matter is one of the outstanding problems in astrophysics.

Galaxy clusters are the largest gravitationally-bound structures in the universe, and play an important role in research on dark matter and cosmology, the study of the structure and evolution of the universe. The use of clusters as dark matter and cosmological probes hinges on scientists’ ability to use objects such as Abell 383 to accurately determine the three-dimensional structures and masses of clusters.

Full Story: http://www.nasa.gov/mission_pages/chandra/multimedia/abell383.html

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Astronomers Get Rare Peek at Early Stage of Star Formation

March 14, 2012 Leave a comment

Image Credit: Bill Saxton, NRAO/AUI/NSF

Image Credit: Bill Saxton, NRAO/AUI/NSF

Using radio and infrared telescopes, astronomers have obtained a first tantalizing look at a crucial early stage in star formation. The new observations promise to help scientists understand the early stages of a sequence of events through which a giant cloud of gas and dust collapses into dense cores that, in turn, form new stars.

The scientists studied a giant cloud about 770 light-years from Earth in the constellation Perseus. They used the European Space Agency’s Herschel Space Observatory and the National Science Foundation’s Green Bank Telescope (GBT) to make detailed observations of a clump, containing nearly 100 times the mass of the Sun, within that cloud.

Full Story: http://www.nrao.edu/pr/2012/clumpcores/

Bright Comet Dives Into Radiation Storm

March 14, 2012 Leave a comment

A bright comet is diving into the sun. It was discovered just last week by SOHO’s SWAN instrument, so it has been named “Comet SWAN.” The comet’s death plunge ( or “swan dive”) comes just as the sun has unleashed a strong flare and radiation storm around Earth. SOHO images of the comet are confused to some degree by energetic protons striking the camera.

Full Story: http://spaceweather.com/archive.php?view=1&day=14&month=03&year=2012

Recycling Galaxies Caught in the Act

March 14, 2012 Leave a comment

When astronomers add up all the gas and dust contained in ordinary galaxies (like our own Milky Way), they find a discrepancy: there is not nearly enough matter for stars to form at the observed rates for long. As a (partial) solution, a matter cycle on gigantic scales has been proposed. In our local galactic neighbourhood, traces of this mechanism had already been found. Now, a study led by Kate Rubin of the Max Planck Institute for Astronomy has found the first direct evidence of such gas flowing back into distant galaxies that are actively forming new stars, validating a key part of “galactic recycling”.

Full Story: http://www.mpia.de/Public/menu_q2.php?Aktuelles/PR/2012/PR120314/PR_120314_en.html

Feeding Habits of Teenage Galaxies

March 14, 2012 Leave a comment

New observations made with ESO’s Very Large Telescope are making a major contribution to understanding the growth of adolescent galaxies. In the biggest survey of its kind astronomers have found that galaxies changed their eating habits during their teenage years – the period from about 3 to 5 billion years after the Big Bang. At the start of this phase smooth gas flow was the preferred snack, but later, galaxies mostly grew by cannibalising other smaller galaxies.

Astronomers have known for some time that the earliest galaxies were much smaller than the impressive spiral and elliptical galaxies that now fill the Universe. Over the lifetime of the cosmos galaxies have put on a great deal of weight but their food, and eating habits, are still mysterious. A new survey of carefully selected galaxies has focussed on their teenage years — roughly the period from about 3 to 5 billion years after the Big Bang.

By employing the state-of-the-art instruments on ESO’s Very Large Telescope an international team is unravelling what really happened. In more than one hundred hours of observations the team has collected the biggest ever set of detailed observations of gas-rich galaxies at this early stage of their development

Full Story: http://www.eso.org/public/news/eso1212/