Letter to the Editor

The characteristic polarized radio continuum distribution of cluster spiral galaxies

¹ CDS, Observatoire astronomique de Strasbourg, 11 rue de l'université, 67000 Strasbourg, France e-mail: bvollmer@astro.u-strasbg.fr
² Astronomical Observatory, Jagiellonian University, Kraków, Poland
³ Max-Planck-Insitut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
⁴ Yale University Astronomy Department, PO Box 208101, New Haven, CT 06520-8101, USA
⁵ Department of Astronomy, Columbia University, 538 West 120th Street, New York, NY 10027, USA

Received: 20 December 2006
Accepted: 19 January 2007

Abstract

Deep observations are presented of the 6 cm polarized radio continuum emission of 8 Virgo spiral galaxies. All galaxies show strongly asymmetric distributions of polarized intensity with elongated ridges located in the outer galactic disk. These features are not found in existing observations of polarized radio continuum emission of field spiral galaxies, where the distribution of 6 cm polarized intensity is generally relatively symmetric and strongest in the interarm regions. We therefore conclude that most Virgo spiral galaxies and, most probably, the majority of cluster spiral galaxies show asymmetric distributions of polarized radio continuum emission due to their interaction with the cluster environment. The polarized continuum emission is sensitive to compression and shear motions in the plane of the sky and thus contains important information about the velocity distortions caused by these interactions.