Broad-band polarimetric follow-up of Type IIP SN 2012aw

Abstract

We present the results based on R-band polarimetric follow-up observations of the nearby (∼10 Mpc) Type II-plateau SN 2012aw. Starting from ∼10 d after the supernova (SN) explo- sion, these polarimetric observations cover ∼90 d (during the plateau phase) and are distributed over nine epochs. To characterize the Milky Way interstellar polarization (ISPMW ), we have observed 14 field stars lying in a radius of 10° around the SN. We have also tried to subtract the host galaxy dust polarization component assuming that the dust properties in the host galaxy are similar to that observed for Galactic dust and the general magnetic field follow the large-scale structure of the spiral arms of a galaxy. After correcting the ISPmw , our analysis infer that SN 2012aw has maximum polarization of 0.85 ± 0.08 per cent but polarization angle does not show much variation with a weighted mean value of ∼138° . However, if both ISPmw and host galaxy polarization components are subtracted from the observed polarization values of SN, maximum polarization of the SN becomes 0.68 ± 0.08 per cent. The distribution of Q and U parameters appears to follow a loop-like structure. The evolution of polarimetric light curve properties of this event is also compared with other well-studied core-collapse SNe of similar type.