January 04, 2013 - SPACE - Colossal magnetized fountains of gamma-ray-emitting gas are spewing from the center of our Milky Way galaxy, researchers say. The amount of magnetic energy contained in these geyser-like outflows "corresponds to the energy liberated by about a million supernova explosions — that is a lot!" study lead author Ettore Carretti, an astrophysicist at the Commonwealth Scientific and Industrial Research Organization in Australia, told SPACE.com. These outflows could help solve mysteries concerning the magnetic field of the Milky Way galaxy, Carretti added.
The galactic halo "was supposed to be a quiet place," Carretti said. "We now know it is continuously fueled with a massive amount of energy." These cone-shaped outflows have denser ridges corkscrewing around their surfaces much like strings of lights wrapped around Christmas trees. These ridges are about 13,000 to 16,000 light-years long and 1,000 light-years wide. "They are made of relativistic charged particles — high-energy particles that move nearly at the speed of light," Carretti said. One of these ridges, dubbed the Galactic Center spur, apparently stems from a super-stellar cluster orbiting the galaxy's center. Super-stellar clusters contain a very large number of young, massive stars. These ridges take on a corkscrew form because matter spewing out from the spinning center of the galaxy moves in spirals. This is because of conservation of angular momentum, the same property that causes ice skaters to spin faster if they draw their arms in. The other two ridges the researchers see are not connected to super-stellar clusters. The researchers suggest the clusters they originated from may no longer be active, thus shedding light on the history of star activity in the galactic core. These outflows might help explain mysteries surrounding the galaxy's magnetic field. "How the galactic magnetic field is generated and sustained is still a mystery, and our finding can be crucial to solve it," Carretti said. The outflows carry magnetic material from the galactic center to the galactic halo, helping to explain why a magnetic field pervades the galaxy, he said. As monstrous as these outflows are, they are no danger to us, Carretti said. "They are not coming in our direction, but go up and down from the galactic plane. We are 30,000 light-years away from the galactic centre, in the plane," he explained in a statement. In the future, the researchers would like to identify the roots of the outflows and their ridges and investigate any connections between the magnetic fields of the outflows and the galaxy's. The scientists detailed their findings in the January issue of the journal Nature. - SPACE.
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A depiction of the magnetic outflows from the Milky Way's center the researchers detected. CREDIT: E. Carretti et al., Nature. |