Self-consistent modelling of the Milky Way’s nuclear stellar disc

• Verfasst von: Sormani, Mattia C. [VerfasserIn]
• Verfasst von: Sanders, Jason L [VerfasserIn]
• Verfasst von: Fritz, Tobias K [VerfasserIn]
• Verfasst von: Smith, Leigh C [VerfasserIn]
• Verfasst von: Gerhard, Ortwin [VerfasserIn]
• Verfasst von: Schödel, Rainer [VerfasserIn]
• Verfasst von: Magorrian, John [VerfasserIn]
• Verfasst von: Neumayer, Nadine [VerfasserIn]
• Verfasst von: Nogueras-Lara, Francisco [VerfasserIn]
• Verfasst von: Feldmeier-Krause, Anja [VerfasserIn]
• Verfasst von: Mastrobuono-Battisti, Alessandra [VerfasserIn]
• Verfasst von: Schultheis, Mathias [VerfasserIn]
• Verfasst von: Shahzamanian, Banafsheh [VerfasserIn]
• Verfasst von: Vasiliev, Eugene [VerfasserIn]
• Verfasst von: Klessen, Ralf S. [VerfasserIn]
• Verfasst von: Lucas, Philip [VerfasserIn]
• Verfasst von: Minniti, Dante [VerfasserIn]
• Titel: Self-consistent modelling of the Milky Way’s nuclear stellar disc
• Verf.angabe: Mattia C. Sormani, Jason L. Sanders, Tobias K. Fritz, Leigh C. Smith, Ortwin Gerhard, Rainer Schödel, John Magorrian, Nadine Neumayer, Francisco Nogueras-Lara, Anja Feldmeier-Krause, Alessandra Mastrobuono-Battisti, Mathias Schultheis, Banafsheh Shahzamanian, Eugene Vasiliev, Ralf S. Klessen, Philip Lucas and Dante Minniti
• E-Jahr: 2022
• Jahr: 2022 March 22
• Umfang: 28 S.
• Fussnoten: Gesehen am 22.04.2022
• Titel Quelle: Enthalten in: Royal Astronomical SocietyMonthly notices of the Royal Astronomical Society
• Ort Quelle: Oxford : Oxford Univ. Press, 1827
• Jahr Quelle: 2022
• Band/Heft Quelle: 512(2022), 2, Seite 1857-1884
• ISSN Quelle: 1365-2966
• DOI: doi:10.1093/mnras/stac639
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1799284506

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.