On the number of young stellar discs in the Galactic Centre

Lockmann, U. and Baumgardt, H. (2009) On the number of young stellar discs in the Galactic Centre. Monthly Notices of the Royal Astronomical Society, 394 4: 1841-1846. doi:10.1111/j.1365-2966.2009.14466.x


Author Lockmann, U.
Baumgardt, H.
Title On the number of young stellar discs in the Galactic Centre
Journal name Monthly Notices of the Royal Astronomical Society   Check publisher's open access policy
ISSN 0035-8711
1365-2966
Publication date 2009-04
Sub-type Article (original research)
DOI 10.1111/j.1365-2966.2009.14466.x
Open Access Status DOI
Volume 394
Issue 4
Start page 1841
End page 1846
Total pages 6
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Language eng
Formatted abstract
Observations of the Galactic Centre show evidence of disc-like structures of very young stars orbiting the central supermassive black hole within a distance of a few 0.1 pc. While it is widely accepted that about half of the stars form a relatively flat disc rotating clockwise on the sky, there is a substantial ongoing debate on whether there is a second, counter-clockwise disc of stars.
By means of N-body simulations using our BHINT code, we show that two highly inclined stellar discs with the observed properties cannot be recognized as two flat circular discs after 5Myr of mutual interaction. Instead, our calculations predict a significant warping of the two discs, which we show to be apparent among the structures observed in the Galactic Centre. While the high eccentricities of the observed counter-clockwise orbits suggest an eccentric origin of this system, we show the eccentricity distribution in the inner part of the more massive clockwise disc to be perfectly consistent with an initially circular disc in which stellar eccentricities increase due to both non-resonant and resonant relaxation. We conclude that the relevant question to ask is therefore not whether there are two discs of young stars, but whether there were two such discs to begin with.
Keyword Black hole physics
Stellar dynamics
Methods: N-body simulations
Galaxy: centre
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
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