TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5080 SUBJECT: GRB060425: new MASTER survey method DATE: 06/05/06 14:15:34 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, N.Tyurina, A.Belinski, D.Kuvshinov, E.Gorbovskoy, A.Krylov, N.Shatskiy, G.Borisov, A.Sankovich, V.Vladimirov, P.Gritsyk, S.Korobkin Sternberg Astronomical Institute, Moscow Union 'Optic' In this circular we proposed and tested new method of optical observations of GRBs by wide field robotic telescopes: survey search of the optical transient like supurnovae in large error box GRBs or dark not X-ray GRB. Especially this method is very important for bright short GRB, that frequently detected by all sky gamma-ray detectors (Konus-Wind, Ulysses, Odyssey, etc) and for which connection with supernovae is not clear. The difference between "OT" and "SN" is the following: OT - is the new optical object without known galaxy. The SN pipe line reduction is based on the searching of the uncatalogized candidate near known galaxies (for example from HyperLeda, http://www-obs.univ-lyon1.fr/hypercat/). MASTER robotic system (http://observ.pereplet.ru, 6 square degrees field) observed GRB060425 error box (GRB_TIME is 2006-04-25 16:57:40 UT, IPN triangulation GCN5005) in survey mode at considerable zenit distances. The weather was good. We have 4 nights (1-2 hours per night) observations: Date Days after GRB Note Limit mean 2006-04-26 1.1 (Lipunov et al.GCN5008) 17.5 2006-04-27 2.1 (Lipunov et al.GCN5026) 17.5 2006-04-30 5.2 17.8 2006-05-03 8.1 17.6 The location of our samples you can find at http://observ.pereplet.ru/images/GRB060425/GRB060425_ErrorBox_master.jpg The unfiltered image is calibrated relative to USNO A2.0 (0.8 R + 0.2 B). The robot not find OT brighter then 17.0 in large IPN error box (J. Cummings, S. Barthelmy et al. GCN5005). The robot not find SN brighter then 17.5. Father observations of the GRB050425 not planed. MASTER team thanks to Konus-Wind team for collaboration. This work is supported by RFFI 04-02-16411 grant. This message can be cited. Mailto: lipunov@sai.msu.ru