Speaker
Anabele-Linda Pardi
(Max-Plank-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany)
Description
Co-authors: Philipp Girichidis1, Thorsten Naab1, Stefanie Walch2, Andrea Gatto1, Richard Wünsch3, Simon C.O. Glover4, Ralf S. Klessen4,5,6, Paul C. Clark7, Christian Baczynski4, Thomas Peters1,8
1Max-Plank-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany
2Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
3Astronomical Institute, Academy of Science of the Czech Republic, Bocni II 1401, 141 31 Prague, Czech Republic
4Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany
5Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
6Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
7School of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3AA, Wales, UK
8Institut für Computergestützte Wissenschaften, Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
We present magnetohydrodynamical (MHD) simulations of the turbulent magnetized
multiphase interstellar medium (ISM) focusing on the connection between the chemical and magnetic filed evolution. In addition to magnetic fields we follow molecule formation and destruction with a background radiation field. Supernova (SN) explosions are the main dynamical driver. The magnetic fields saturate when amplification is balanced by dissipation (or vice-versa) regardless of the initial field strength. For 3 SN/Myr, a density of 1 p/ccm and 2 pc resolution the magnetic field saturates at 1 μG. The saturation level and the saturation time, however, are sensitive to the initial density, SN rate and numerical resolution. A magnetic field of ~ 1 μG suppresses the formation of molecular hydrogen for 50 Myrs due to the additional magnetic pressure in the dense ISM. We find a systematic effect of the magnetic field on the ISM phases volume filling fractions (vff) like a reduced (by a factor of two) vff of the hot ionized gas and we discuss possible reasons. We conclude that magnetic fields change the chemistry and the multiphase structure of the ISM. As our saturated magnetic field strengths are lower than observed values, the results are likely a conservative lower limit.
Author
Anabele-Linda Pardi
(Max-Plank-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany)