TITLE: GCN CIRCULAR NUMBER: 15430 SUBJECT: GRB 131030A - RoboPol optical afterglow polarimetry DATE: 13/11/01 13:16:41 GMT FROM: Dmitry Blinov at U of Crete/FORTH M. Balokovic, T. Hovatta, O. King, T. Pearson, A. Readhead Caltech, USA D. Blinov, N. Kylafis, G. Panopoulou, I. Papadakis, I. Papamastorakis, V. Pavlidou, P. Reig, K. Tassis University of Crete/FORTH, Greece P. Khodade, C. Rajarshi, A. Ramaprakash, R. Rouneq Inter-University Centre for Astronomy and Astrophysics, India E. Angelakis, I. Myserlis, L. Fuhrmann, J. A. Zensus Max Planck Institute for Radio Astronomy, Germany R. Feiler, A. Kus, B. Pazderska, E. Pazderski Nicolaus Copernicus University, Poland We observed GRB 131030A (Swift Trigger 576238; Troja et al. GCN 15402) using the RoboPol (http://robopol.org) polarimeter on the 1.3m Skinakas observatory telescope (Greece). We confirm the presence of an uncatalogued source at the location (RA=23h00m16s, Dec=-05d22m05s). Preliminary analysis showed that emission of the source is linearly polarized at high significance. Further analysis will be presented elsewhere. [GCN OPS NOTE(01nov13): This was delayed in distribution by 17 hours because a new entry in the list had to be added.]