Magnetohydrodynamic Simulations of the Formation of Molecular Clouds toward the Stellar Cluster Westerlund 2: Interaction of a Jet with Clumpy Interstellar Medium

Abstract

The formation mechanism of CO clouds observed with NANTEN2 and Mopra telescope toward the stellar cluster Westerlund 2 is studied by three-dimensional magnetohydrodynamic (MHD) simulations taking into account the interstellar cooling. These molecular clouds show a peculiar shape composing of an arc-shaped cloud in one side of a TeV-ray source HESS J1023-575 and a linear distribution of clouds (jet clouds) in another side. We propose that these clouds are formed by the interaction of a jet with interstellar neutral hydrogen (HI) clumps. By studying the dependence of the shape of dense cold clouds formed by shock compression and cooling on the filling factor of HI clumps, we found that the density distribution of HI clumps determines the shape of molecular clouds formed by the jet-cloud interaction; arc-clouds are formed when the filling factor is large. On the other hand, when the filling factor is small, molecular clouds align with the jet. The jet propagates faster in models with small filling factors.

arXiv comment26 pages, 13 figures; published in ApJ

References in corpus (12)

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Cited by in corpus (4)

• A Small-Scale Investigation of Molecular Emission toward the Tip of the Western Lobe of W50/SS433
• Energy estimation of high energy particles associated with the SS433/W50 system through radio observation at 1.4 GHz
• Molecular clouds at the eastern edge of radio nebula W50
• Young Massive Star Clusters as TeV Emitters: Constraints from H.E.S.S. and LHAASO