The link between solenoidal turbulence and slow star formation in G0.253+0.016
| Autor: | Christoph Federrath, Andrew Walsh, John Bally, James M. Jackson, J. M. D. Kruijssen, Yanett Contreras, Roland M. Crocker, Guido Garay, Steven N. Longmore, Leonardo Testi, Jill Rathborne |
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| Rok vydání: | 2016 |
| Předmět: |
010504 meteorology & atmospheric sciences
Milky Way FOS: Physical sciences Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences symbols.namesake 0103 physical sciences 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics QC QB 0105 earth and related environmental sciences Physics Spiral galaxy Solenoidal vector field Turbulence Star formation Astronomy and Astrophysics Plasma Astrophysics - Astrophysics of Galaxies Magnetic field Astrophysics - Solar and Stellar Astrophysics Mach number Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) symbols Astrophysics::Earth and Planetary Astrophysics |
| Zdroj: | Proceedings of the International Astronomical Union |
| ISSN: | 1743-9221 1743-9213 |
| Popis: | 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. Comment: IAU Symposium 322 "The Multi-Messenger Astrophysics of the Galactic Centre", eds. R. M. Crocker, S. N. Longmore, G. V. Bicknell |
| Databáze: | OpenAIRE |
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