Early optical imaging polarimetry of type I superluminous supernova 2020ank

We present imaging polarimetry observations of the recently discovered type I superluminous supernova 2020ank, in order to use (a)symmetry of the ejecta and SN photosphere that manifest themselves in the supernova lights as a probe of its explosion mechanism and investigate the energy sources that power the superluminous supernovae behind the scene. We have obtained linear imaging polarimetry in the optical with the Alhambra Faint Object Spectrograph and Camera mounted on the 2.5 m Nordic Optical Telescope. Our observations on March 1, 2020 manifest negligible polarization at 0.6 ± 0.3% level, shortly after the supernova reached its maximum brightness in mid-February. The low degree of polarization implies that the explosion of SN 2020ank is nearly spherical; this is consistent with results of polarimetric observations of other superluminous supernovae at early epochs.