Fitting the magnetar model to the observed BVR_cI_c quasi-bolometric light curve of SN 2012aa. We adopted the model proposed by Inserra et al. (2013). However, we only consider the power supplied by the magnetar, not that of radioactive decay. The errors associated with the observations have been calculated after propageting the errors in magnitudes only. While getting the best-fit model we have excluded the data that corresponds to the bump in the light curve (marked by the open circles). The Residual of the best-fit model has been shown in the lower panel along with the fitted data points (filled circles). Here Residual is defined as: Residual = (Observeddata−Modeldata) /Modeldata. For the best-fit model we found M_ej = 16.0 ± 1.7 M_⊙, the magnetic field of the proto-magnetar B = (6.5 ± 0.3) × 10¹⁴ G, and the initial spin period P = 7.1 ± 0.6 ms.