Kinematics of Galactic Centre clouds shaped by shear-seeded solenoidal turbulence
Journal article, 2023
The Central Molecular Zone (CMZ; the central ∼500 pc of the Galaxy) is a kinematically unusual environment relative to the Galactic disc, with high-velocity dispersions and a steep size-linewidth relation of the molecular clouds. In addition, the CMZ region has a significantly lower star formation rate (SFR) than expected by its large amount of dense gas. An important factor in explaining the low SFR is the turbulent state of the star-forming gas, which seems to be dominated by rotational modes. However, the turbulence driving mechanism remains unclear. In this work, we investigate how the Galactic gravitational potential affects the turbulence in CMZ clouds. We focus on the CMZ cloud G0.253+0.016 ('the Brick'), which is very quiescent and unlikely to be kinematically dominated by stellar feedback. We demonstrate that several kinematic properties of the Brick arise naturally in a cloud-scale hydrodynamics simulation, that takes into account the Galactic gravitational potential. These properties include the line-of-sight velocity distribution, the steepened size-linewidth relation, and the predominantly solenoidal nature of the turbulence. Within the simulation, these properties result from the Galactic shear in combination with the cloud's gravitational collapse. This is a strong indication that the Galactic gravitational potential plays a crucial role in shaping the CMZ gas kinematics, and is a major contributor to suppressing the SFR, by inducing predominantly solenoidal turbulent modes.
Galaxy: centre
stars: formation
ISM: kinematics and dynamics
galaxies: ISM
ISM: evolution
ISM: clouds
Author
Maya Petkova
Astronomisches Rechen-Institut Heidelberg
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
J. M. D. Kruijssen
Technical University of Munich
Coolresearch.io
Jonathan D. Henshaw
Liverpool John Moores University
Max Planck Society
S. Longmore
Coolresearch.io
Liverpool John Moores University
S. C.O. Glover
Heidelberg University
Mattia C. Sormani
Heidelberg University
Lucia Armillotta
Princeton University
Ashley T. Barnes
University of Bonn
R. S. Klessen
Heidelberg University
Francisco Nogueras-Lara
European Southern Observatory (ESO)
Robin G. Tress
Observatoire de Sauverny
Jairo Armijos-Abendaño
Escuela Politécnica Nacional
Cardiff University
L. Colzi
Centro de Astrobiologia (CAB)
C. Federrath
Australian National University
Australian Research Council (ARC) Discovery Project Funding and Discovery International Award (DIA)
P. J.V. Garcia
Universidad Catolica del Norte
Chinese Academy of Sciences
A. Ginsburg
University of Florida
C. Henkel
King Abdulaziz University
Max Planck Society
S. Martin
European Southern Observatory Santiago
Atacama Large Millimeter-submillimeter Array (ALMA)
D. Riquelme
Max Planck Society
University of La Serena
Víctor M. Rivilla
Centro de Astrobiologia (CAB)
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 525 1 962-968Subject Categories
Astronomy, Astrophysics and Cosmology
Other Physics Topics
DOI
10.1093/mnras/stad2344