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jueves, 28 de mayo de 2009

NEW SUPERNOVA PICTURE: Blast Seen in "Exploding" Galaxy

Peering behind the dusty veil of a nearby galaxy, astronomers have found a new supernova, the closest seen in the past five years.

The stellar explosion happened in the galaxy M82, which lies a mere 12 million light-years from Earth. Visible-light images of the galaxy—such as the Hubble Space Telescope picture at left—make M82 look as if it's exploding, due to a plethora of supernovae happening deep inside.

Thick dust and gas shroud the explosions from view, but instruments that can see in radio wavelengths had previously revealed the vast number of supernova remnants, so astronomers were sure that a new supernova would be due anytime.

Sure enough, an international team of astronomers using radio telescopes spotted the recent supernova in M82 on April 8 (bottom-right inset).

"I then looked back into older data we had from March and May last year [middle insets], and there it was as well, outshining the entire galaxy!" team member Andreas Brunthaler, of the Max Planck Institute for Radio Astronomy in Germany, said in a statement.

Combining data from several telescopes, the team revealed that the supernova had created a ring of debris, which is expanding at more than 25 million miles (40 million kilometers) an hour. Working backward, the study authors estimate that the star exploded in late January or early February 2008.

The explosion happened close enough that, if it hadn't been for its surroundings of dense material, the bright flash would have been visible from Earth via backyard telescopes, noted team member Heino Falcke from Radboud University Nijmegen in the Netherlands.

"This cosmic catastrophe," Falcke said, "shows that, using our radio telescopes, we have a front-row seat to observe the otherwise hidden universe."

Findings published this week in the journal Astronomy & Astrophysics.

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