Radio and Polarization Properties in the Disk and Halo of Edge-On Spirals

Abstract

AbstractWe have observed a small sample of edge-on galaxies in total and linearly polarized radio continuum emission at λ6.2 cm, using the Effelsberg 100m telescope. The resulting maps were combined with available VLA data in order to obtain high-sensitivity radio images which have a sufficient angular resolution and do not suffer from the so-called missing-spacing problem.From an analysis of these images (together with 2.8cm and 20cm data) we get the following results: 1. The radio emission perpendicular to the plane can be described by a two-component exponential distribution with scale-heights of ~ 300 pc and ~ 1.8 kpc, independently of the star forming activity and interaction state. 2. In the disk of the non-interacting galaxies of our sample the thermal fraction of the emission seems to be higher than usually deduced from observations of face-on galaxies. 3. The fractional polarization p increases with increasing galactic height, reaches a maximum at h ~ 1 – 3 kpc, and decreases again. In general p is lower in actively star forming galaxies.