http://arxiv.org/abs/1910.08656
Stars form from gravitationally unstable clumps, which can be interpreted as the near inner scale of a mass conserving, fragmentation cascade of giant molecular clouds (GMC). We first show that the properties of a mass conserving fragmentation cascade are consistent with a scale-independence of $\epsilon_{ff}(R)$–the ratio of star formation rate to the total cloud mass of scale $R$ divided by the corresponding free fall time. We further show that the amount of feedback needed to stop the fragmentation cascade and suppress star formation decreases with the scale at which this feedback couples to the clouds. Regulating feedback by low mass stellar outflows couples to the gas on small, sub-parsec, scales leaving most of inertial range of fragmentation cascade unfettered, but still suppressing the star formation rate. Destructive feedback from high mass stars globally destroys the cloud complexes. This duality combines to maintain a low star formation rate, scale independence of $\epsilon_{ff}$, Larson-type relations, the required conversion rate of $H_2$ back to $H I$ in the Galaxy, and contributes turbulent fluctuations for reseeding the next fragmentation cascade.
E. Blackman
Tue, 22 Oct 19
5/91
Comments: 6 pages, submitted to MNRAS
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