Sunday, 7 December 2014
Astronomers Discover Extremely Rare Jet-Emitting Spiral Galaxy
(Click image to Dwonload)
1649+2635 is a spiral galaxy located about 800 million light-years away from our Solar System.
It is only the fourth spiral galaxy known to produce large, powerful jets of subatomic particles moving at nearly the speed of light.
The first galaxy of this type, 0313-192, was found in 1998 in the galaxy cluster Abell 428.
The second, Speca (J1409-030), was revealed in 2011 by images from the Sloan Digital Sky Survey and the Very Large Array.
And the third, J2345-0449, was found earlier this year near the massive galaxy cluster RBS 2042.
Giant jets of superfast particles are powered by supermassive black holes at the cores of galaxies. Both elliptical and spiral galaxies harbor such black holes, but only J1649+2635 and three other spiral galaxies have been seen to produce large jets. These jets pour outward from the poles of rapidly-rotating disks of material orbiting the black hole.
The problem is that spiral galaxies are not supposed to have such large jets.
“In order to figure out how these jets can be produced by the ‘wrong’ kind of galaxy, we realized we needed to find more of them,” said Dr Minnie Mao from the National Radio Astronomy Observatory, who is the lead author of the paper accepted for publication in the Monthly Notices of the Royal Astronomical Society (arXiv.org preprint).
Dr Mao and his colleagues, with help from participants of an online project called the Galaxy Zoo, looked at images of galaxies from the visible-light Sloan Digital Sky Survey and classified them as spiral, elliptical, or other types.
Next, they decided to cross-match the SDSS visible-light spirals with galaxies in a catalog that combines data from the NRAO VLA Sky Survey and the Faint Images of the Radio Sky at Twenty Centimeters survey.
The results of the cross-matching showed that one of the galaxies, J1649+2635, is both a spiral galaxy and has powerful twin radio jets.
“This is the first time that a galaxy was first identified as a spiral, then subsequently found to have large radio jets. It was exciting to make such a rare find,” said team member Dr Ryan Duffin from the University of Virginia and the National Radio Astronomy Observatory.
J1649+2635 is unusual not only because of its jets, but also because it is the first example of a ‘grand design’ spiral galaxy with a large optical halo (about 313,000 light-years in diameter) surrounding it.
The galaxy harbors an enormous black hole with the mass of 300 million to 700 million times the mass of the Sun.
“This galaxy presents us with many mysteries. We want to know how it became such a strange beast,” Dr Mao said.
Source : Sci-news