Proceedings of the International Astronomical Union

Table of Contents - 2008 - Volume 4, Symposium S259 (Cosmic Magnetic Fields: From Planets, to Stars and Galaxies)  

Contributed Papers

Magnetism in the nearby galaxy M 33

F. S. Tabatabaeia1, M. Krausea1, R. Becka1 and A. Fletchera2

a1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany email: tabataba@mpifr-bonn.mpg.de, mkrause@mpifr-bonn.mpg.de, rbeck@mpifr-bonn.mpg.de

a2 School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K., email: andrew.fletcher@ncl.ac.uk

Abstract

Using high-resolution data of the linearly polarized intensity and polarization angle at 3.6, 6.2, and 20 cm together with a 3-D model of the regular magnetic field, we study variations of the structure, strength, and energy density of the magnetic field in the Scd galaxy M 33. The regular magnetic field consists of a horizontal component (represented by an axisymmetric mode from 1 to 3 kpc radius and a superposition of axisymmetric and bisymmetric modes from 3 to 5 kpc radius) and a vertical component. However, the inferred ‘vertical field’ may be partly due to a galactic warp. We estimate the average total and regular magnetic field strengths as xs22436.4 and 2.5 μG, respectively. Generation of interstellar magnetic fields by turbulent gas motion in M 33 is indicated as the turbulent and magnetic energy densities are about equal.

Keywords

  • Galaxies: individual: M33 – radio continuum: galaxies – galaxies: magnetic field – galaxies: ISM