Self-consistent modelling of the Milky Way's nuclear stellar disc
(2022) In Monthly Notices of the Royal Astronomical Society 512(2). p.1857-1884- 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}... (More)
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 $M{\rm NSD} = 10.5{+1.1}{-1.0} \times 108 \, \, \rm M\odot$, 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.
(Less)
- author
- organization
- publishing date
- 2022-05-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Galaxy: centre, Galaxy: kinematics and dynamics, Galaxy: structure
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 512
- issue
- 2
- pages
- 1857 - 1884
- publisher
- Oxford University Press
- external identifiers
-
- scopus:85128030913
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/stac639
- language
- English
- LU publication?
- yes
- id
- 01139e01-bd5d-40af-9011-07775591d769
- date added to LUP
- 2022-06-20 16:01:48
- date last changed
- 2024-04-15 18:45:37
@article{01139e01-bd5d-40af-9011-07775591d769, abstract = {{<p>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 $M{\rm NSD} = 10.5{+1.1}{-1.0} \times 108 \, \, \rm M\odot$, 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. </p>}}, author = {{Sormani, Mattia C. and Sanders, Jason L. and Fritz, Tobias K. and Smith, Leigh C. and Gerhard, Ortwin and Schödel, Rainer and Magorrian, John and Neumayer, Nadine and Nogueras-Lara, Francisco and Feldmeier-Krause, Anja and Mastrobuono-Battisti, Alessandra and Schultheis, Mathias and Shahzamanian, Banafsheh and Vasiliev, Eugene and Klessen, Ralf S. and Lucas, Philip and Minniti, Dante}}, issn = {{0035-8711}}, keywords = {{Galaxy: centre; Galaxy: kinematics and dynamics; Galaxy: structure}}, language = {{eng}}, month = {{05}}, number = {{2}}, pages = {{1857--1884}}, publisher = {{Oxford University Press}}, series = {{Monthly Notices of the Royal Astronomical Society}}, title = {{Self-consistent modelling of the Milky Way's nuclear stellar disc}}, url = {{http://dx.doi.org/10.1093/mnras/stac639}}, doi = {{10.1093/mnras/stac639}}, volume = {{512}}, year = {{2022}}, }