Comparison between the observations of SN 2012au at ∼289 d after explosion and a set of contemporaneous He-star explosion models with magnetar power. For comparison, a model with decay power only is also shown (bottom-row panel). The observations have been corrected for redshift and extinction and the model has been scaled to the distance of SN 2012au. Any additional flux scaling is indicated by a label at right. [See Section 10.1 for discussion.]