TITLE: GCN CIRCULAR NUMBER: 10525 SUBJECT: GRB 100316D: Possible Supernova DATE: 10/03/19 12:32:17 GMT FROM: Andrew Levan at U.of Leicester K. Wiersema (U. Leicester), P. D'Avanzo (INAF-OAB), A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), D. Malesani (DARK/NBI), S. Covino (INAF-OAB) report for a larger collaboration: "We obtained a third epoch of observations of the localization of GRB 100316D (Stamatikos et al. GCN 10496; Starling et al. GCN 10519) using Gemini South and GMOS. Observations began at 23:48 UT on March 18, and were obtained in the r-band under excellent seeing (0.5"). Image subtraction reveals that the source previously identified by Levan et al (GCN 10523), has brightened between the two observations by ~0.3 magnitudes. We suggest that this object represents the rising supernova associated with GRB 100316D. Images of the field, and the subtraction can be found at http://www.star.le.ac.uk/~anl/100316D Further observations are planned. We thank the staff of Gemini for their help in executing these observations"