NASA's Chandra Observatory Confirms Evidence of Jet in Milky Way's Black Hole Sagittarius A*
NASA's Chandra Observatory has finally confirmed the evidence of jets in the Sagittarius A* (Sgr A*), a supermassive black hole located 26,000 light years away from Earth in the center of the Milky Way Galaxy.
Ever since Sgr A* was discovered in 1974, it is being constantly monitored by the X-ray telescopes of Swift satellite. After decades of search using a variety of telescopes including NASA's Chandra X-ray Observatory and the National Science Foundation's Very Large Array (VLA) radio telescope have finally confirmed the evidence of a jetsof high energy particle in Milky Way's black hole Sgr A*.
"For decades astronomers have looked for a jet associated with the Milky Way's black hole. Our new observations make the strongest case yet for such a jet," Zhiyuan Li of Nanjing University in China, lead author of a study said in a statement.
Jet streams of high energy are not new concept as they are found throughout the Universe both on large and small scales. Jets are emitted by young stars as well as black holes a thousand times bigger than the Milky Way's black hole. They play a crucial role in transferring energy away from the central object and also regulating the rate at which the new stars are formed.
"We were very eager to find a jet from Sgr A* because it tells us the direction of the black hole's spin axis. This gives us important clues about the growth history of the black hole," said Mark Morris of the University of California at Los Angeles, a co-author of the study.
Based on the observations, the study reveals that the spin axis of Sgr A* is pointing in a direction that is parallel to the rotation axis of the Milky Way, indicating that the gas and the dust slowly drifted into Sgr A* over the past 10 billion years. They also suspect that if there was a collision of the Milky Way with other large galaxies in the recent past, the central black holes then would merge with Sgr A* and due to this the jet could point in random directions.
It appears that the jet is gushing into gas near Sgr A*due to which it produced X-ray whose presence was detected by Chandra and the radio emission was observed by VLA. The straight line of X-ray emitting gas pointing towards Sgr A* and shock front are two key evidences for jet. Shock front are like the sonic boom that is seen in radio data, it is here where the jets strike the gas.
The scientists, who have been observing these jets for decades, assume that the jets are emitted when some material approaching the black hole is redirected outward. It is known that at the moment Sgr A* is consuming less material, hence it is not surprising that the jet produced is weak. They also suspect that the reason why the jet is not seen in the opposite direction is due to the gas and dust that obstructs the sight from our planet or the lack of material required to propagate the jet.
Researchers suggest that the jet may have been inactive for the past few hundred years based on the faint region surrounding the Sgr A*,. A previous Chandra study declared that the black hole was a million times brighter than what it appears today.
"We know this giant black hole has been much more active at consuming material in the past. When it stirs again, the jet may brighten dramatically," said co-author Frederick K. Baganoff of the Massachusetts Institute of Technology in Cambridge, Mass.
The findings appear in an upcoming edition of The Astrophysical Journal.