NASA's Fermi telescope finds giant structure in the middle of the Milky Way

[News_Editor]

NASA's Fermi telescope finds giant structure in the middle of the Milky Way

2010-11-10 08:37:32 GMT+7 (ICT)

WASHINGTON D.C. (BNO NEWS) -- The National Aeronautics and Space Administration (NASA) on Tuesday announced that its Fermi telescope discovered a giant, mysterious structure in the middle of the Milky Way galaxy.

The structure looks like a pair of bubbles extending above and below the galaxy’s center. From end to end, the newly discovered gamma-ray bubbles spans 50,000 light-years, about half of the galaxy’s diameter, and may be only a few million years old.

"What we see are two gamma-ray-emitting bubbles that extend 25,000 light-years north and south of the galactic center," said Doug Finkbeiner, an astronomer at the Harvard-Smithsonian Center for Astrophysics , who first recognized the feature. "We don't fully understand their nature or origin."

The structure may be the remnant of an eruption from a super sized black hole at the center of the Milky Way. The bubbles extend more than half of the visible sky, from the constellation Virgo to the constellation Grus.

Finkbeiner and his team discovered the giant structure by processing publicly available data from Fermi’s Large Area Telescope (LAT), which is the most sensitive and highest-resolution gamma-ray detector ever launched. Gamma rays are the highest-energy form of light.

The bubbles were not discovered earlier as a fog of gamma rays appears throughout the sky when particles moving near the speed of light interact with light and interstellar gas in the Milky Way. The LAT team constantly refines models to uncover new gamma-ray sources obscured by the diffuse emission.

Finkbeiner and his team used various estimated of the fog in order to isolate it from the LAT data and unveil the giant lobes. Scientists are currently conducting more analyses to better understand how the structure was formed. The bubble emissions are much more energetic than the gamma-ray fog seen elsewhere in the galaxy.

The shape of the structure suggests that it was formed as a result of a large and rapid energy release, but the source of which remains a mystery. One possibility is that fast particle jet powered by matter fell towards the center of the super massive black hole as seen in other galaxies. However, there is no evidence that the Milky Way’s has such jet.

Another theory is that the bubble may have formed as a result of gas outflows from a burst of star formation, possibly the one that produced many massive star clusters in the galaxy’s center several million years ago.

"Whatever the energy source behind these huge bubbles may be, it is connected to many deep questions in astrophysics,†said David Spergel, a scientist at Princeton University in New Jersey.

-- © BNO News All rights reserved 2010-11-10