TITLE: GCN CIRCULAR NUMBER: 6809 SUBJECT: GRB 070920B: NOT optical observations DATE: 07/09/21 10:54:32 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo, J. Gorosabel, M. Jelinek, A.J. Castro-Tirado (IAA-CSIC, Granada), D. Perez-Ramirez (U. Jaen), R. Corradi (ING, La Palma), T. Liimets (ING, La Palma and Tartuu Obs.) report: We have observed the field of GRB070920B (Racusin et al., GCNC 6808) using the 2.5m NOT telescope (+ALFOSC) at Roque de los Muchachos Observatory in V, R and I bands (180 s each) at high airmass. The mean time of the observations was 21.0486 Sep. 2007 (UT), ~4.1 hours after the burst. We do not detect any bright afterglow candidate within the Swift/BAT error box. However, we do see a red, stationary object (detected in R and I bands) slightly over the DSS2 limit that does not seem to have its correspondent in the DSS2 images. The coordinates of this object are (J2000 +/- 0.5"): R.A.: 00:00:34.56 Dec.: -34:49:08.4 Further observations are needed to confirm wether this could be the optical afterglow of GRB 070920B. A finding chart comparing with the DSS2 can be found at: www.iaa.es/~deugarte/GRBs/070920B/GRB070920B.jpg This message can be quoted.