Signs of star formation close to supermassive black hole detected
Washington: Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have discovered signs of star formation perilously close to the supermassive black hole at the center of the Milky Way Galaxy.
If confirmed, this would be the first time that star formation was observed so close to the galactic center.
The center of our galaxy, 27,000 light-years away in the direction of the constellation Sagittarius, is home to a monstrous black hole with a mass of four million Suns.
Extending outward from this gravitational behemoth for many light-years is a turbulent region of space that is thought to be wracked by such extreme tidal forces that any star-forming clouds of dust and gas would be stretched thin and shredded long before infant stars could emerge.
Yet against these extreme odds, ALMA spotted telltale jets of material bursting out of what appear to be dense cocoons of gas and dust.
These jets, if they were observed in more placid surroundings, would indicate the formation of a young star.
"People think it is very hard to form stars near a supermassive black hole," Northwestern University's Farhad Zadeh, first author of the paper, said.
"This is because the gravity of the black hole produces extreme tidal forces that would stretch and elongate molecular clouds, preventing them from ever accumulating enough mass to trigger star formation. But what we seem to have found are patches of dust and gas that have become so dense that they are able to overcome their inhospitable surroundings," he said.
Zadeh and his colleagues speculate that these molecular clouds have become so massive and dense, possibly by colliding together, that they cross the all-important threshold that allows internal gravity to take over, starting a chain of events that inexorably leads to the birth of a new star.
As this process evolves, material in these clouds clumps together and collapses into an ever-denser mass that begins to rotate faster and faster.
This rapid rotation, possibly coupled with the star's magnetic field, accelerates some of the material and shoots it out into space along the nascent star's axis of rotation.
The findings are published in the Astrophysical Journal Letters.