Abstract
We follow the near radial infall of a prolate cloud on to a 4 ×
106 M⊙ supermassive black hole in the Galactic
Centre using smoothed particle hydrodynamics. We show that a prolate
cloud oriented perpendicular to its orbital plane naturally produces a
spread in angular momenta in the gas which can translate into misaligned
discs as is seen in the young stars orbiting Sagittarius A*. A turbulent
or otherwise highly structured cloud is necessary to avoid cancelling
too much angular momentum through shocks at closest approach. Our
standard model of a 2 × 104 M⊙ gas cloud
brought about the formation of a disc within 0.3 pc from the black hole
and a larger, misaligned streamer at 0.5 pc. A total of 1.5 ×
104 M⊙ of gas formed these structures. Our
exploration of the simulation parameter space showed that when star
formation occurred, it resulted in top-heavy initial mass functions with
stars on eccentric orbits with semi-major axes 0.02-0.3 pc and
inclinations following the gas discs and streamers. We suggest that the
single event of an infalling prolate cloud can explain the occurrence of
multiple misaligned discs of young stars.
| Original language | English |
|---|---|
| Pages (from-to) | 353-365 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 433 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Jul 2013 |
Keywords / Materials (for Non-textual outputs)
- accretion
- accretion discs
- hydrodynamics
- stars: formation
- Galaxy: centre