On the Formation of Compact Stellar Disks Around Sgr A*

Understand

The recent identification of one or two sub-parsec disks of young, massive stars orbiting the ~4e6 solar mass black hole Sgr A* has prompted an "in-situ" scenario for star formation in disks of gas formed from a cloud captured from the Galactic center environment.

• To date there has been no explanation given for the low angular momentum of the disks relative to clouds passing close to the center.
• Here we show that the partial accretion of extended Galactic center clouds, such as the 50 km/s giant molecular cloud, that temporarily engulf Sgr A* during their passage through the central region of the Galaxy provide a natural explanation for the angular momentum and surface density of the the observed stellar disks.
• The captured cloud material is gravitationally unstable and forms stars as it circularizes, potentially explaining the large eccentricity and range of inclinations of the observed stellar orbits.