GRB 081130B
GCN Circular 8597
Subject
GRB 081130B: MASTER prompt optical observations
Date
2008-12-03T17:13:15Z (18 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@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@sai.msu.ru
GCN Circular 8593
Subject
GRB 081130B: Fermi GBM detection
Date
2008-12-02T21:26:01Z (18 years ago)
From
Alexander van der Horst at NASA/MSFC <Alexander.J.VanDerHorst@nasa.gov>
A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the Fermi GBM
Team:
"At 15:05:15.72 UT on 30 November 2008, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 081130 (trigger 249750316 / 081130.629).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 14.1, Dec = +4.2 (J2000 degrees, equivalent to J2000 0h 56m,
+4d 10'), with a statistical uncertainty of 3.5 degrees (radius, 1-sigma
containment, statistical only; there is additionally a systematic error
which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 66 degrees.
The GBM light curve shows a spike of ~12 seconds and a possible precursor
at ~T0-28 seconds. The time-averaged spectrum from T0-0.8s to T0+7.4s is
best fit by a power-law function with an exponential high-energy cutoff.
The power-law index is -0.77 +/- 0.12 and the cutoff energy, parameterized
as Epeak, is 152 +/- 17 keV. The fluence (50-300 keV) in this time
interval is (1.3 +/- 0.1)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.3s in the 50-300 keV band is 1.8 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."