Galactic Magnetic Fields: Cellular or Filamentary Structure?
Abstract
We have examined the possibility that the galactic field is composed of cells or filaments elongated by plasma motions or by the differential rotation of the galactic disk. Such cells could result from special events, and each would then contain its own independent magnetic-field structure. Our analysis of available data indicates that there is a significant correlation between the signs of the observed rotation measure between different radio sources as a function of their angular separation out to angles of about 40 . The anticorrelation expected for a uniform field component is absent, indicating that any uniform component would have to be an order of magnitude weaker than the ambient fields. One or more localized field "patches" seem indicated near 100 = 80 , b" = 0 . We discuss these results in terms of a cellular field model. Cosmic-ray propagation would be sensitive to such structuring. Stars are also shown to be a potential source of very fine filamentary field (much less than a parsec in width) which would not be resolved in the rotation measure data, but which might account for the starlight polarization data. Subject headings: interstellar matter - magnetic fields - stellar winds
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1973
- DOI:
- 10.1086/151914
- Bibcode:
- 1973ApJ...179..771M