The Magnetic Field Geometry in M82 and Centaurus A

Imaging polarimetry at 1.65 and 2.2 $\mu $m is presented for the classicstarburst galaxy M82 and the advanced merger system Cen A. Polarimetry at nearIR wavelengths allows the magnetic field geometry in galaxies to be probed muchdeeper into dusty regions than optical polarimetry. In M82, the magnetic fieldthroughout the nucleus has a polar geometry, presumably due to the massivevertical flow that is a result of the intense star formation there. Fully twothirds of the line of sight dust through to the center of M82 contains avertical magnetic field. In Cen A, the prominent dust lane shows a normalplanar field geometry. There is no indication of significant disturbance in thefield geometry in the dust lane and the polarization strength is near normalfor the amount of extinction. Either the magnetic field geometry was wellmaintained during the merger, or it reestablished itself very easily