The flow-driven picture of molecular cloud formation: A parameter study of the effects of shear on hydrodynamic instabilities and star formation

POSTER

Abstract

In recent years a flow-driven picture of molecular cloud formation has been presented to explain the narrow age spread of stellar clusters in the solar neighborhood. In this scenario clouds of molecular hydrogen form in the shock boundary between two supersonic streams of atomic hydrogen on scales of tens of parsecs, due to thermal, gravitational, and non-linear thin shell instabilities. These instabilities lead to simultaneous local collapse across the length of the cloud, forming dense cores and stars within a few shock-crossing times. In recent simulations of head-on collisions, observable parameters such as age spread and star formation efficiency have been indirectly measured and found to be relatively accurate. In an effort to extend the robustness of these investigations, our work includes the effects of shear; a reasonable expectation in the interstellar medium. In our work we find that shear flows can inhibit global and local collapse, but still permit the formation of dense cores due to breakup of the shock boundary. Final stellar angular momentum distribution and star formation rates are compared, as well as post-processing of data to form CII maps. These simulations are done in AstroBEAR, a magnetohydrodynamic code with adaptive mesh refinement and self-gravity.

Authors

  • Christina Haig

    University of North Carolina, Chapel Hill

  • J.K. Hwang

    Western Kentucky University, University of Pardubice, Francis Marion University, Clemson University Professor, Francis Marion University Professor, Undergraduate Administrator, Oak Ridge National Laboratory, Oak Ridge, Tennessee, Austin Peay State University, University Strenwarte-Muenchen, Seoul National University, Gatton Academy for Science and Mathematics, Alabama A\&M University, Cygnus, Center for Nanophase Materials Science at Oak Ridge National Laboratory, Vanderbilt University, Fisk Univ, 2Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, NOVA Center, Western Kentucky University, Department of Physics, Florida A\&M University, Tallahassee, FL-32307, Correlated Electron Materials Group, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6061 USA, Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA, Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14627, USA, The Institute of Optics, University of Rochester, Rochester, NY 14627, USA, Universidade Estadual Paulista (UNESP), Clark Atlanta University, Deapartment of Physics \& Astronomy, Georgia State University, USA, Department of Electrical and Computer Engineering, McGill University, Montreal, QC H3A 2A7, Canada, Oak Ridge National Laboratory, University of South Alabama, Samford University, University of Rochester, University of North Carolina, Chapel Hill, Sandia National Laboratories, New Mexico State University, University of Tennessee Space Institute, Shanghai Jiao Tong University, Shanghai, China, University of Leeds, Leeds, UK, Georgia State University, Atlanta GA, University of Alabama at Birmingham, National High Magnetic Field Laboratory, Prairie View A\&M University, Brookhaven National Laboratory, University of Southern Indiana, Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, JINR(Dubna), Tsinghua Univ., LBNL, Vanderbilt Univ., Vanderbilt Univ./Univ. of Tennessee, Knoxville, Vanderbilt Univ./Univ. of Kentucky, GANIL, Vanderbilt Univ./Union Univ., JINR, ORAU, Tsinghua University, LNBL

  • J.K. Hwang

    Western Kentucky University, University of Pardubice, Francis Marion University, Clemson University Professor, Francis Marion University Professor, Undergraduate Administrator, Oak Ridge National Laboratory, Oak Ridge, Tennessee, Austin Peay State University, University Strenwarte-Muenchen, Seoul National University, Gatton Academy for Science and Mathematics, Alabama A\&M University, Cygnus, Center for Nanophase Materials Science at Oak Ridge National Laboratory, Vanderbilt University, Fisk Univ, 2Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, NOVA Center, Western Kentucky University, Department of Physics, Florida A\&M University, Tallahassee, FL-32307, Correlated Electron Materials Group, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6061 USA, Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA, Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14627, USA, The Institute of Optics, University of Rochester, Rochester, NY 14627, USA, Universidade Estadual Paulista (UNESP), Clark Atlanta University, Deapartment of Physics \& Astronomy, Georgia State University, USA, Department of Electrical and Computer Engineering, McGill University, Montreal, QC H3A 2A7, Canada, Oak Ridge National Laboratory, University of South Alabama, Samford University, University of Rochester, University of North Carolina, Chapel Hill, Sandia National Laboratories, New Mexico State University, University of Tennessee Space Institute, Shanghai Jiao Tong University, Shanghai, China, University of Leeds, Leeds, UK, Georgia State University, Atlanta GA, University of Alabama at Birmingham, National High Magnetic Field Laboratory, Prairie View A\&M University, Brookhaven National Laboratory, University of Southern Indiana, Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, JINR(Dubna), Tsinghua Univ., LBNL, Vanderbilt Univ., Vanderbilt Univ./Univ. of Tennessee, Knoxville, Vanderbilt Univ./Univ. of Kentucky, GANIL, Vanderbilt Univ./Union Univ., JINR, ORAU, Tsinghua University, LNBL