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

Abstract

The formation mechanism of CO clouds observed with the NANTEN2 and Mopra telescopes toward the stellar cluster Westerlund 2 is studied by 3D magnetohydrodynamic simulations, taking into account the interstellar cooling. These molecular clouds show a peculiar shape composed of an arc-shaped cloud on one side of the TeV γ -ray source HESS J1023-575 and a linear distribution of clouds (jet clouds) on the other side. We propose that these clouds are formed by the interaction of a jet with clumps of interstellar neutral hydrogen (H i). By studying the dependence of the shape of dense cold clouds formed by shock compression and cooling on the filling factor of H i clumps, we found that the density distribution of H i 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.

Authors:
;  [1]; ; ; ;  [2];  [3]
  1. National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan)
  2. Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)
  3. Department of Physics, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan)
Publication Date:
OSTI Identifier:
22663764
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 836; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON MONOXIDE; CLOUDS; DISTRIBUTION; GAMMA RADIATION; GAMMA SOURCES; HYDROGEN; INTERACTIONS; INTERSTELLAR SPACE; MAGNETOHYDRODYNAMICS; SHOCK WAVES; SIMULATION; STAR CLUSTERS; TELESCOPES; TEV RANGE

Citation Formats

Asahina, Yuta, Kawashima, Tomohisa, Furukawa, Naoko, Enokiya, Rei, Yamamoto, Hiroaki, Fukui, Yasuo, and Matsumoto, Ryoji, E-mail: asahina@cfca.jp. Magnetohydrodynamic Simulations of the Formation of Molecular Clouds toward the Stellar Cluster Westerlund 2: Interaction of a Jet with a Clumpy Interstellar Medium. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA5C86.
Asahina, Yuta, Kawashima, Tomohisa, Furukawa, Naoko, Enokiya, Rei, Yamamoto, Hiroaki, Fukui, Yasuo, & Matsumoto, Ryoji, E-mail: asahina@cfca.jp. Magnetohydrodynamic Simulations of the Formation of Molecular Clouds toward the Stellar Cluster Westerlund 2: Interaction of a Jet with a Clumpy Interstellar Medium. United States. doi:10.3847/1538-4357/AA5C86.
Asahina, Yuta, Kawashima, Tomohisa, Furukawa, Naoko, Enokiya, Rei, Yamamoto, Hiroaki, Fukui, Yasuo, and Matsumoto, Ryoji, E-mail: asahina@cfca.jp. Mon . "Magnetohydrodynamic Simulations of the Formation of Molecular Clouds toward the Stellar Cluster Westerlund 2: Interaction of a Jet with a Clumpy Interstellar Medium". United States. doi:10.3847/1538-4357/AA5C86.
@article{osti_22663764,
title = {Magnetohydrodynamic Simulations of the Formation of Molecular Clouds toward the Stellar Cluster Westerlund 2: Interaction of a Jet with a Clumpy Interstellar Medium},
author = {Asahina, Yuta and Kawashima, Tomohisa and Furukawa, Naoko and Enokiya, Rei and Yamamoto, Hiroaki and Fukui, Yasuo and Matsumoto, Ryoji, E-mail: asahina@cfca.jp},
abstractNote = {The formation mechanism of CO clouds observed with the NANTEN2 and Mopra telescopes toward the stellar cluster Westerlund 2 is studied by 3D magnetohydrodynamic simulations, taking into account the interstellar cooling. These molecular clouds show a peculiar shape composed of an arc-shaped cloud on one side of the TeV γ -ray source HESS J1023-575 and a linear distribution of clouds (jet clouds) on the other side. We propose that these clouds are formed by the interaction of a jet with clumps of interstellar neutral hydrogen (H i). By studying the dependence of the shape of dense cold clouds formed by shock compression and cooling on the filling factor of H i clumps, we found that the density distribution of H i 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.},
doi = {10.3847/1538-4357/AA5C86},
journal = {Astrophysical Journal},
number = 2,
volume = 836,
place = {United States},
year = {Mon Feb 20 00:00:00 EST 2017},
month = {Mon Feb 20 00:00:00 EST 2017}
}