About SciDoc
Document Search

DOCUMENT METADATA
SLAC Publication: SLAC-PUB-17052
SLAC Release Date: July 7, 2017
AB INITIO SIMULATIONS OF A SUPERNOVA DRIVEN GALACTIC DYNAMO IN AN ISOLATED DISK GALAXY
Butsky, Iryna.
We study the magnetic field evolution of an isolated spiral galaxy, using isolated Milky Way-mass galaxy formation simulations and a novel prescription for agnetohydrodynamic (MHD) supernova feedback. Our main result is that a galactic dynamo can be seeded and driven by supernova explosions, resulting in magnetic fields whose strength and morphology is consistent with observations. In our model, supernovae supply thermal energy, and a low level magnetic field along with their ejecta. The thermal... Show Full Abstract
We study the magnetic field evolution of an isolated spiral galaxy, using isolated Milky Way-mass galaxy formation simulations and a novel prescription for agnetohydrodynamic (MHD) supernova feedback. Our main result is that a galactic dynamo can be seeded and driven by supernova explosions, resulting in magnetic fields whose strength and morphology is consistent with observations. In our model, supernovae supply thermal energy, and a low level magnetic field along with their ejecta. The thermal expansion drives turbulence, which serves a dual role by fficiently mixing the magnetic field into the interstellar medium, and amplifying it by means of turbulent dynamo. The computational prescription for MHD supernova feedback has been implemented within the publicly available ENZO code, and is fully described in this paper. This improves upon ENZOs existing modules for hydrodynamic feedback from stars and active galaxies. We find that the field attains mG-levels over Gyr-time scales throughout the disk. The field also develops large-scale tructure, which appears to be correlated with the disks spiral arm density tructure. We find that seeding of the galactic dynamo by supernova ejecta predicts a persistent correlation between gas metallicity and magnetic field strength. We also generate all-sky maps of the Faraday rotation measure from the simulation-predicted magnetic field, and present a direct comparison with observations. Show Partial Abstract
Download File: