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

TL;DR

This study presents R-band polarimetric observations of SN 2012aw over 90 days, analyzing interstellar and host galaxy polarization effects to understand the supernova's intrinsic polarization and its evolution.

Contribution

It provides the first detailed polarimetric follow-up of SN 2012aw, including correction for interstellar polarization and analysis of polarization evolution during the plateau phase.

Findings

Maximum polarization of 0.85% observed in SN 2012aw.

Polarization angle remains relatively constant at ~138 degrees.

Polarimetric light curve shows loop-like structure in Q-U space.

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 days after the SN explosion, these polarimetric observations cover ~90 days (during the plateau phase) and are distributed over 9 epochs. To characterize the Milky Way interstellar polarization (ISP_MW ), we have observed 14 field stars lying in a radius of 10 degree 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 IS_PMW , our analysis infer that SN 2012aw has maximum polarization of 0.85% +- 0.08% but polarization angle does not show much variation with a weighted mean value of ~138 degree. However, if both ISP_MW and host galaxy polarization (ISP_HG ) components are subtracted from the observed polarization values of SN, maximum polarization of the SN becomes 0.68% +- 0.08%. The distribution of Q and U parameters appears to follow a loop like structure. The evolution of polarimetric light curve (PLC) properties of this event is also compared with other well studied core-collapse supernovae of similar type.