• Corpus ID: 3090770

New clues to the magnetic field structure of M 31

@article{Han1998NewCT,
  title={New clues to the magnetic field structure of M 31},
  author={J. L. Han and Rainer Beck and Ewine F. van Dishoeck Max-Planck-Institut fuer Radioastronomie and Bonn and Germany Shanghai Astronomical Observatory and Chinese Academy of Sciences and Beijing and China.},
  journal={Astronomy and Astrophysics},
  year={1998},
  volume={335},
  pages={1117-1123}
}

• J. Han, R. Beck, +5 authors China.
• Published 4 May 1998
• Physics
• Astronomy and Astrophysics

We observed 21 polarized background radio sources in the field of M31 at 1.365 GHz and 1.652 GHz, and determined their rotation measures (RMs). The RM data show that the regular magnetic field of the disk probably extends from about 5 kpc to 25 kpc from the center with similar structure. The RMs obtained from the polarized emission from M31 at $\lambda$6 cm and $\lambda$11 cm indicate that M31 might have a weak poloidal field in its tenuous halo. Observational features of the odd and even dynamo modes in a galaxy are discussed. An even mode (S0) dynamo may operate in M31.