Photometric Observations of Supernova 2013cq Associated with GRB 130427A

We observed the afterglow of GRB 130427A with the RATIR instrument on the 1.5-m Harold L. Johnson telescope of the Observatorio Astronomico Nacional on Sierra San Pedro Martir. Our homogenous $griZYJH$ photometry extends from the night of burst to three years later. We fit a model for the afterglow. There is a significant positive residual which matches the behavior of SN 1998bw in the $griZ$ filters; we suggest that this is a photometric signature of the supernova SN 2013cq associated with the GRB. The peak absolute magnitude of the supernova is $M_r=-18.43\pm0.11$.