The centre of our Galaxy hosts almost two hundreds of very young stars , a subset of which is orbiting the central supermassive black hole ( SMBH ) in a relatively thin disc-like structure .
First analyses indicated a power-law surface density profile of the disc , \Sigma \propto R ^ { \beta } with \beta = -2 .
Recently , however , speculations about this profile arose .
In particular , it now seems to be better described by a sort of broken power-law .
By means of both analytical arguments and numerical N -body modelling , we show that such a broken power-law profile is a natural consequence of the two-body relaxation of the disc which is , due to small relative velocities of stars on nearby co-planar Keplerian orbits around the SMBH , effective enough to affect the evolution of the disc on time-scales comparable to its estimated age .
In the inner , densest part of the disc , the profile becomes rather flat ( \beta \approx - 1 ) while the outer parts keep imprints of the initial state .
Our numerical models show that the observed projected surface density profile of the young stellar disc can result from two-body relaxation driven evolution of a disc with initial single power-law profile with -2 \lesssim \beta \lesssim - 1.5 .
In addition , we suggest that two-body relaxation may have caused a significant radial migration of the S-stars towards the central SMBH , thus playing an important role in their formation scenario .