We performed an integrated optical polarization survey of 70 nearby galaxies to study the relationship between linear polarization and galaxy properties. To date this is the largest survey of its kind. The data were collected at McDonald Observatory using the Imaging Grism Polarimeter on the Otto Struve 2.1 m telescope. Most of the galaxies did not have significant level of linear polarization, where the bulk is <1%. A fraction of the galaxies showed a loose correlation between the polarization and position angle of the galaxy, indicating that dust scattering is the main source of optical polarization. The unbarred spiral galaxies are consistent with the predicted relationship with inclination from scattering models of ~sin 2 i.
The Astrophysical Journal
- Pub Date:
- March 2012
- galaxies: ISM;
- magnetic fields;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- accepted in ApJ, 21 pages, 5 figures