GCN Circular 15570
A.Volnova (IKI), E. Klunko (ISTP), M. Eselevich (ISTP), A. Pozanenko(IKI) report on behalf of larger GRB follow-up collaboration: We report about revised photometry of the GRB 131127A (Markwardt et al., GCN 15516) published earlier (Klunko et al., GCN 15519). Using combined image of full data set of the observations on Nov. 27 we do not detect any optical counterpart in the enhanced XRT error circle (Evans et al., GCN 15520). The details of the photometry are the following: UT start t-T0 Filter Exp. OT UL (mid, days) (s) (3 sigma) 10:40:06 0.04680 R 4650 n/d 22.5 The photometry is based on the same 3 USNO-B1.0 stars listed in the GCN 15519. The deep upper limit obtained at ~67 min (mid time) after burst trigger together with Swift/XRT observations (www.swift.ac.uk/xrt_curves/00579571/flux.qdp) suggests the upper limit of optical-to-X-ray spectral slope beta_OX = -0.02 and classify the GRB 131127A as a dark burst according to Jakobsson (Jakobsson et al., 2004, ApJ, 614, L21).