TITLE: GCN CIRCULAR NUMBER: 6532 SUBJECT: SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations DATE: 07/06/14 02:14:40 GMT FROM: Alexander Stefanescu at MPE A. Stefanescu (1), A. Slowikowska (2)(3), G. Kanbach (1), S. Duscha (1), F. Schrey (1), H. Steinle (1), Z. Ioannou (4) of the OPTIMA-Burst Team report the following: (1)=MPE, Garching, (2)=FORTH, Heraklion (3)=NCAC, Torun (4)=Univ. of Crete "OPTIMA-Burst at the 1.3m Skinakas Observatory of the University of Crete, Greece continued observations of the OT associated with SWIFT J195509.6+261406 (GRB 070610). On 2007-06-12 we observed the source during 21:00-23:10 UT, using our photon counting mode. In this period we detected flaring activity consisting of only four short, dim flares: t_start duration approx peak mag. 21:55:45 16s 18.9 22:23:13 18s 18.7 22:26:33 45s 18.4 22:34:14 17s 19.2 On 2007-06-13 we observed the source between 20:15-20:43 UT and 20:59-22:10 UT. We did not detect any flaring activity, the source stayed below the background level detected by our photon counters at all times. The brightness of a fluctuation 1 sigma above background noise corresponds roughly to 21.4 mag. We conclude that the flaring activity of the optical counterpart of SWIFT J195509.6+261406 (GRB 070610) is greatly diminished, or may have even come to an end." This message may be cited. [GCN OPS NOTE(17jun07): Per author's request, the two epoch dates were corrected from "2007-06-13" to "2007-06-12" in the 2nd paragraph and from "2007-06-14" to "2007-06-13" in the 3rd paragraph.]