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DR. BRIAN LACKI
On Tuesday, January 21, 2014, Dr. Brian Lacki from Princeton University New Jersey, USA will give a talk on "Storm and Stress: Supernova-Driven Turbulence and the Chaotic Starburst ISM" starting at 10:15 am in NB 7/67.
Interested parties are welcome to attend!
Abstract: I explain my investigation into how supernovae power turbulence in the ISMs of starburst regions, and the implications for magnetic fields and cosmic rays. In weaker starbursts, supernovae blast open a hot (~40 MK) phase that escapes as a superwind. I calculate that supernovae can drive Mach ~ 1 turbulence in the hot wind. In the densest starbursts, like Arp 220, the volume is instead filled by cold molecular gas. Supernovae alone can drive turbulence in this gas to ~20 - 30 km/s, despite strong radiative losses. I predict magnetic field strengths of 70 microGauss in the Galactic Center starburst, 200 microGauss in NGC 253 and M82, and 2 milliGauss in Arp 220's nuclei. I show how supernova driving of turbulence naturally results in equipartition between several ISM phases in starbursts. I also discuss why CR diffusion may be very slow in these regions. Instead, turbulent mixing by the ISM may transport CRs, a very different process.