TITLE: GCN CIRCULAR NUMBER: 8597 SUBJECT: GRB 081130B: MASTER prompt optical observations DATE: 08/12/03 17:13:15 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalognikh Ural State University, Kourovka S.Yazev, K.Ivanov Irkutsk State University One of the four MASTER Very Wide Field Cameras located at Kislovodsk (http://apollo.sai.msu.ru/, D=50 mm, 4x1000 square degrees, 35'' per pix) has observed Fermi error box (A.J. van der Horst, GCN Circ 8593) with 5s exposures during all night without time gap between images (Gorbovskoy et al., GCN 8585). These unfiltered images are calibrated relative to Tycho stars (V). The magnitude limit of the each emage is ~11m. Now we present results final result. We do not detect any new source inside error box (A.J. van der Horst, GCN Circ 8593) brighter than 12.0 mag before and after trigger time. The optical fluence during the 15s-GRBurst is limited by <= 1.5 x 10_-9 erg/cm_2 excluding possible absorbtion. The fluence (50-300 keV) in this time interval is (1.3 +/- 0.1)E-6 erg/cm^2 (A.J. van der Horst, GCN Circ 8593). So: Optical Fluence/Gamma-Fluence(50-300 keV) ~ < 1/1000 The ratio for GRB080319B is Optical Fluence/Gamma-Fluence(15-150 keV) ~ 1/25 (Naked Eye GRB, Racusin, Karpov et al., Nature, vol.455, 183, 2008). The video and other info are available at http://observ.pereplet.ru/images/GRB081130B/grb_film.html Note: the GRB was at the edge of the FOW. The message may be cited. mailto: lipunov@sai.msu.ru