Virial Ratio: Direct Evaluation from Molecular Cloud Data and the Challenges of Improving Accuracy
arXiv:1905.00024 · doi:10.3847/1538-4357/ab1e4f
Abstract
The virial ratio between kinetic and gravitational terms provides key insight into the balance of forces that confine a molecular cloud, but the clumpy and filamentary structures of resolved clouds make it difficult to evaluate this ratio in a consistent way. For clouds with resolved maps of column density as well as a line tracer, we demonstrate that the gravitational energy can be estimated directly from observations in a manner similar to the kinetic energy. This offers improved diagnostic power and consistency. Disentangling a cloud from foreground and background materials is a persistent challenge, for which we introduce a strategy based on Abel's transform. We provide proofs of principle using simulated clouds.
Published to ApJ, 9 pages, 6 figures, 1 table
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- Cloud fragmentation cascades and feedback: on reconciling an unfettered inertial range with a low star formation rate
- Why most molecular clouds are gravitationally dominated