SDSSg-band image (7.7 arcmin × 7.2 arcmin) of the SN field containing the galaxy M95. A vector with a degree of polarization 0.23 per cent and position angle of 147° is drawn at the location of SN 2012aw (see text in Section 3.2 for details). A vector with a 0.20 per cent polarization and PA of 90° is shown for a reference (top right). The approximate orientation of the magnetic field at the location of SN has been determined on the basis of structure of the spiral arm (see Section 3.2 for more details). The location of the SN is represented by a square symbol. North is up and east is to left as shown in the figure.