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GCN Circular 8516

GRB 081102: MASTER refind and final results
2008-11-11T15:50:10Z (16 years ago)
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.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinski, I.Zalognikh
Ural State University, Kourovka

S.Yazev, K.Ivanov
Irkutsk State University

Two of the four  MASTER Very Wide Field Cameras located at Kislovodsk
(, D=50 mm, 4x1000 square degrees, 35'' per pix) has 
observed the Swift-BAT GRB081102 error box  (Mangano et al., GCN Circ 
8470, Lipunov et al., GCN 8464, 8471) 
with 5s exposures during all night without time gap between images. There 
are  two  separeted (~702m) mount with double cameras.

Now we present results from the North and South mounts.

These unfiltered images are calibrated relative to Tycho stars (V).
We do not detect any new source at the XRT position
reported in GCN Circ. 8470 (Mangano et al.) brighter than 13.0 
mag before and after trigger time.
The photometry results +-4 min around trigger time:

  T-T_trigger            m_lim (S/N=3)         Exposure         Coadd

-255s... 0... 255 s       11.8                  5s              yes 
-2min...0...+2 min        12.7                 2x30s             12
-2min...0...+2 min        13.0                 2x60s             24

The optical fluence during the 40s-GRBurst is limited by

     <= 1.6x10_-8 erg/cm_2

including 2.8 magnitude  absorbtion (Ukwatta et al., Circ 8462).
The  BAT-fluence is aboute 2.3x10_-6 erg/cm_2 (15-150 keV) 
(Fenimore et al., GCN 8468).


Optical Fluence/Gamma-Fluence(15-150keV) ~ < 1/140

Same ratio for GRB080319B is ~ 1/25 (Naked Eye GRB) in 15-150 keV 
(Racusin, Karpov et al., Nature, vol.455, 183, 2008).

Scientific Master Team Report   are available at

Note: the GRB was at the edge of the FOW in both cameras.
The message may be cited.

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