Sormani, Mattia C;
Sanders, Jason L;
Fritz, Tobias K;
Smith, Leigh C;
Gerhard, Ortwin;
Schodel, Rainer;
Magorrian, John;
... Minniti, Dante; + view all
(2022)
Self-consistent modelling of the Milky Way's nuclear stellar disc.
Monthly Notices of the Royal Astronomical Society
, 512
(2)
pp. 1857-1884.
10.1093/mnras/stac639.
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Abstract
The nuclear stellar disc (NSD) is a flattened high-density stellar structure that dominates the gravitational field of the Milky Way at Galactocentric radius $30\, {\rm pc}\lesssim R\lesssim 300\, {\rm pc}$. We construct axisymmetric self-consistent equilibrium dynamical models of the NSD in which the distribution function is an analytic function of the action variables. We fit the models to the normalized kinematic distributions (line-of-sight velocities + VIRAC2 proper motions) of stars in the NSD survey of Fritz et al., taking the foreground contamination due to the Galactic Bar explicitly into account using an N-body model. The posterior marginalized probability distributions give a total mass of $M_{\rm NSD} = 10.5^{+1.1}_{-1.0} \times 10^8 \, \, \rm M_\odot$, roughly exponential radial and vertical scale lengths of $R_{\rm disc} = 88.6^{+9.2}_{-6.9} \, {\rm pc}$ and $H_{\rm disc}=28.4^{+5.5}_{-5.5} \, {\rm pc}$, respectively, and a velocity dispersion $\sigma \simeq 70\, {\rm km\, s^{-1}}$ that decreases with radius. We find that the assumption that the NSD is axisymmetric provides a good representation of the data. We quantify contamination from the Galactic Bar in the sample, which is substantial in most observed fields. Our models provide the full 6D (position + velocity) distribution function of the NSD, which can be used to generate predictions for future surveys. We make the models publicly available as part of the software package agama.
| Type: | Article |
|---|---|
| Title: | Self-consistent modelling of the Milky Way's nuclear stellar disc |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stac639 |
| Publisher version: | https://doi.org/10.1093/mnras/stac639 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions. |
| Keywords: | Galaxy: centre, Galaxy: kinematics and dynamics, Galaxy: structure |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10147284 |
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