Juan Diego Soler, Patrick Hennebelle, Peter G. Martin, Marc-Antoine Miville-Deschênes, C. Barth Netterfield, Laura M. Fissel
We describe a morphological imprint of magnetization found when considering the relative orientation of the magnetic field direction with respect to the density structures in simulated turbulent molecular clouds. This imprint was found using the Histogram of Relative Orientations (HRO): a new technique that utilizes the gradient to characterize the directionality of density and column density structures on multiple scales. We present results of the HRO analysis in three models of molecular clouds in which the initial magnetic field strength is varied, but an identical initial turbulent velocity field is introduced, which subsequently decays. The HRO analysis was applied to the simulated data cubes and mock-observations of the simulations produced by integrating the data cube along particular lines of sight. In the 3D analysis we describe the relative orientation of the magnetic field with respect to the density structures, showing that: 1.The magnetic field shows a preferential orientation parallel to most of the density structures in the three simulations. 2.The relative orientation changes from parallel to perpendicular in regions with density over a critical density $n_{T}$ in the highest magnetization case. 3.The change in the relative orientation is largest for the highest magnetization and decreases in the lower magnetization cases. This effect is also present in the projected maps, where we consider the relative orientation of column density structures and polarization pseudovectors. The described change in the relative orientation of the magnetic field is potentially measurable using submillimeter polarization observations of molecular clouds and can be used to complement the estimates of magnetic field strength found with techniques based on the Chandrasekhar-Fermi method.
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http://arxiv.org/abs/1303.1830
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