Almost every galaxy is known to have a supermassive black hole at its centre and our Milky Way is no different. Little is known about why all galaxies have this super-dense element deep in their heart, but there is new information regarding a specific black hole that is in our galaxy.
A new study shows that the supermassive black hole at the centre of the Milky Way galaxy is not spinning as much which means it is unlikely to have a jet. A jet is formed when ionised matter (charge) outflows from a disc of rotation when a black hole spins; it can almost reach the speed of light.
The research was carried out by Centre for Astrophysics, Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) at Northwestern University, and Harvard & Smithsonian (CfA), and published in Letters.
Supermassive Black Holes (SMBH) are humongous. They are characterised by their spin and mass. The SMBH in Milky Way Galaxy has been named as Sgr A*. These SMBHs are said to influence everything; from formation to the evolution of their galaxies.
“Black holes release a huge amount of energy that removes gas from galaxies and therefore shapes their star formation history,” said one of the co-authors, Dr Avi Loeb, a professor and astronomer, according to ANI.
Though we know SMBH has a critical impact on the host galaxy, little is known about their spin or how it adds up to the bigger picture. The effect might be too subtle to study, said Loeb.
Loeb, along with Dr Giacomo Fragione, of CIERA, has been studying Sgr A* to learn more about the birth of our own galaxy.
For this, they studied stellar orbits around it because black holes are just a little tricky to understand and fully explore.
They focused on S-star spatial distribution (the stars closest to SgrA*). Through these, they analysed the light’s speed; to constrain, or place limits on the spin of the black hole.
“We concluded that the supermassive black hole in the centre of our galaxy is spinning slowly. This can have major implications for the detectability of activity in the centre of our galaxy and the future observations of the Event Horizon Telescope,” said Fragione.
The S-Stars seem to be in two organised lanes. The team says if Sgr A* was spinning faster, the surrounding stars would be a little misaligned by now.
They assume that Sgr A* could be spinning at 10% of its maximal value (in correlation with SMBH at light speed spin). And this conclusion also suggests that the jets associated with fast-spinning SMBHs cannot be present in a slow-spinning SMBH like Sgr A*. However, to confirm this, the team is awaiting data analysis from the Event Horizon Telescope.