TITLE: GCN CIRCULAR NUMBER: 13920 SUBJECT: GRB 121027A: Brightening IR counterpart DATE: 12/10/29 08:36:06 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan (U. Warwick), R.Starling, N.R. Tanvir, K. Wiersema (U. Leicester), A. R. Lopez-Sanchez (AAO/Macquarie University), T. Young (ANU), K. Glazebrook (Swinburne), L. Spitler (Macquarie University/AAO), and S. Lee (AAO) report: "We observed the candidate afterglow of GRB 121027A (Evans et al. GCN 13906; Starling et al. GCN 13916) with the Anglo Australian Telescope for a second epoch on the night of 28 October 2012. The second epoch was obtained ~32 hours after the burst, and 26 hours after the first epoch reported in Starling et al. (GCN 13916). We clearly detect the afterglow candidate, and find that it has brightened by approximately 1 magnitude in the K-band between the two epochs. This confirms it as the infrared afterglow of GRB 121027A. We note that rising behaviour in the IR over this time period is extremely unusual, and given the extremely bright, and long lived X-ray afterglow (e.g. Serino et al. GCN 13908) could be indicative of an event similar in nature to Swift J1644+57."