[vsnet-grb-info 7506] GRB 090328B: MASTER-Irkutsk prompt optical short burst observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9065
SUBJECT: GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
DATE:    09/04/01 08:47:35 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

K.Ivanov, S.Yazev, 
Irkutsk State University


E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov
Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parhomenko,
   Kislovodsk Solar Station of the Pulkovo Observatory

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


There are 6 MASTER Very Wide Field cameras located at Kislovodsk and 
Irkutsk  with common FOW = 6000 square degrees 
(http://observ.pereplet.ru/).

One of the two  MASTER Very Wide Field Cameras located at Irkutsk
(D=50 mm, 2x1000 square degrees, 11 Mpx) has observed  ~20% 1-sigma Fermi
error box  (A. Goldstein, GCN 9056) with 1s exposure
during  all night: befoure, during and after GRB Time
without time gap between images.

Our unfiltered images are calibrated relative to Tycho stars (V).
The magnitude limit of the each emage is  ~9.1 m at the edge of FOW (some 
ising was attend at this night).

We do not detect OT inside 20% part of the error box.


We  conclude (in the case that GRB inside our FOW ):

1). the optical fluence during the short 0.3 s GRBurst is limited by

                        ~<=  3 x 10E-9 erg/cm_2

excluding possible  host galaxy absorbtion.

The event fluence (8-1000 keV) in this time interval is
(9.61 +/- 0.31)E-07 erg/cm^2 (A. Goldstein, GCN 9056).

So:

2).  Optical-Fluence/Gamma-Fluence(8-1000 keV) ~ < 1/300

The same ratio for long GRB080319B is

Optical-Fluence/Gamma-Fluence(8 - 1000 keV) ~ 1/140

(Naked Eye GRB, Racusin, Karpov et al., Nature, vol.455, 183, 2008).


The film of our observations  is available at

http://observ.pereplet.ru/images/GRB090320B/GRB090328B.gif

Black circles are the 1-sigma and 3-sigma 
error boxes (A. Goldstein, GCN 9056).


The reduction is continued.

The message may be cited.

mailto: lipunov at sai.msu.ru