[vsnet-grb-info 7013] GRB 081130B: MASTER prompt optical observations

[GCN Circulars]

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  <gcncirc at observ.inetcomm.ru>

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 at sai.msu.ru