1995A&A...303..691H

We observed the radio continuum emission of the interacting spiral galaxy NGC 2276 with the VLA and the WSRT. i) The spectrum of the nonthermal emission is steeper than in normal spiral galaxies and reveals a gradual steepening with frequency, as expected for strong synchrotron losses of cosmic-ray electrons. ii) The radio emission is stronger than can be accounted for by the star formation rate or the assumption of equipartition between cosmic rays and magnetic field so that NGC 2276 clearly deviates from the far-infrared-radio continuum correlation: The radio luminosity is ∼2.5 times higher than expected from the far-infrared luminosity. The total field strength over the whole disk (B_t) of ∼19µG is enhanced by a factor ∼1.6 compared to what is expected from the far-infrared luminosity. iii) The strongest linearly polarized emission is found south of the line-of-nodes along the southwestern sharp edge. The uniform magnetic field component (B_u) is strongest there (∼10µG) and shows a spiral-like structure. iv) The strong overall B_t, the locally strong and aligned B_u, and the long tail of uniform field towards the southeast are probably caused by the interaction between NGC 2276 and NGC 2300 by compression of the gas and the frozen-in field and/or excitation of a strong galactic dynamo, possibly operating in a non-axisymmetric mode.