The link between solenoidal turbulence and slow star formation in G0.253+0.016

Abstract

Star formation in the Galactic disc is primarily controlled by gravity, turbulence, and magnetic fields. It is not clear that this also applies to star formation near the Galactic Centre. Here we determine the turbulence and star formation in the CMZ cloud G0.253+0.016. Using maps of 3mm dust emission and HNCO intensity-weighted velocity obtained with ALMA, we measure the volume-density variance ${\sigma }_{\rho /{\rho }_0}=1.3\pm 0.5$ and turbulent Mach number $\mathcal{M}=11\pm 3$. Combining these with turbulence simulations to constrain the plasma $\beta =0.34\pm 0.35$, we reconstruct the turbulence driving parameter $b=0.22\pm 0.12$ in G0.253+0.016. This low value of $b$ indicates solenoidal (divergence-free) driving of the turbulence in G0.253+0.016. By contrast, typical clouds in the Milky Way disc and spiral arms have a significant compressive (curl-free) driving component ($b>0.4$). We speculate that shear causes the solenoidal driving in G0.253+0.016 and show that this may reduce the star formation rate by a factor of 7 compared to nearby clouds.

IAU Symposium 322 "The Multi-Messenger Astrophysics of the Galactic Centre", eds. R. M. Crocker, S. N. Longmore, G. V. Bicknell

References in corpus (20)

• Theory of Star Formation
• The Density Probability Distribution in Compressible Isothermal Turbulence: Solenoidal versus Compressive Forcing
• What is Driving the HI Velocity Dispersion?
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
• Magnetic Fields in High-Mass Infrared Dark Clouds
• Magnetically Regulated Star Formation in 3D: The Case of Taurus Molecular Cloud Complex
• The Global Evolution of Giant Molecular Clouds. I: Model Formulation and Quasi-Equilibrium Behavior
• Modeling jet and outflow feedback during star cluster formation
• Driving Turbulence and Triggering Star Formation by Ionizing Radiation
• Unfolding the Laws of Star Formation: The Density Distribution of Molecular Clouds
• A cluster in the making: ALMA reveals the initial conditions for high-mass cluster formation
• The density structure and star formation rate of non-isothermal polytropic turbulence
• Turbulence sets the initial conditions for star formation in high-pressure environments
• The ISM in spiral galaxies: can cooling in spiral shocks produce molecular clouds?
• Simulations of spiral galaxies with an active potential: molecular cloud formation and gas dynamics
• Can Protostellar Jets Drive Supersonic Turbulence in Molecular Clouds?
• Time Varying Dynamical Star Formation Rate
• Assessing molecular outflows and turbulence in the protostellar cluster Serpens South
• Protostellar Outflow Evolution in Turbulent Environments

Cited by in corpus (11)

• Seed magnetic fields in turbulent small-scale dynamos
• The IMF and multiplicity of stars from gravity, turbulence, magnetic fields, radiation and outflow feedback
• The SAMI Galaxy Survey: Gas velocity dispersions in low-$z$ star-forming galaxies and the drivers of turbulence
• Magnetic field fluctuations in anisotropic, supersonic turbulence
• Quantifying the effects of spatial resolution and noise on galaxy metallicity gradients
• A new method for spatially resolving the turbulence driving mixture in the ISM with application to the Small Magellanic Cloud
• The SAMI Galaxy Survey: Bayesian Inference for Gas Disk Kinematics using a Hierarchical Gaussian Mixture Model
• Growth or Decay -- I: universality of the turbulent dynamo saturation
• Lagrangian statistics of a shock-driven turbulent dynamo in decaying turbulence
• Gravitationally Bound Gas Determines Star Formation in the Galaxy
• The turbulence driving parameter of molecular clouds in disc galaxies