TITLE: GCN CIRCULAR NUMBER: 22107 SUBJECT: GRB 171010A: possible SN component DATE: 17/11/07 00:01:02 GMT FROM: Antonino Cucchiara at UVI A. Cucchiara (University of the Virgin Islands), L. G. Strolger (STScI) report on behalf of a larger collaboration: We observed the location of the LAT GRB 171010A (Omodei et al., GCN 21985; Poolakkil & Meegan, GCN 21992; Sharma et al., GCN 21990) at z = 0.33 (Kankare et al., GCN 22002) with the 1.3 m Remotely Controlled Telescope (RCT) located at Kitt Peak Observatory in optical R-band. We performed a series of 120s exposures under good conditions (2.2 arcseconds seeing) and airmass of 1.4 on average. Beginnng October 23.41 UT (12.21 days post burst) we identified an excess over the host galaxy flux and a subsequent fading optical source at the location of the GRB+Host galaxy. These are indicative of a possible supernova component (as suggested by de Ugarte Postigo et al. GCN 22096). T-T0 R Mag (days) (Host+SN) 12.21 18.87 +- 0.10 14.21 19.64 +- 0.13 15.21 20.21 +- 0.19 The magnitude are calibrated agains several USNO-B1 objects in the field and are not corrected for galactic extinction. Further observations are planned. We thank the RCT Consortium for permitting these observations. RCT is operated by South Carolina State University, Villanova University, and University of Western Kentucky.