The Origin of Magnetic Fields in Galaxies: What Should to See at High Redshifts?
Spiral galaxies, including our own, have magnetic fields embedded in the
gas of their disks. These fields are typically coherent and have an energy
density comparable to the turbulent energy density of the interstellar
medium. Conventional dynamo theory has some difficulty explaining the
existence of these fields at the current epoch, so recent observations
showing that magnetic fields with comparable amplitudes were present when
the universe was about a billion years old have come as a surprise. I
will review the arguments for weak seed fields from the early universe,
and show that turbulent processes in young galaxies can explain these
results. I argue that observations of magnetic fields at high redshift
cannot be used to argue for novel processes in the early universe.
|Date: ||Mardi, le 2 décembre 2008|
|Lieu: ||Université McGill|
| ||Ernest Rutherford Physics Building, R.E. Bell Conference Room (room 103)|