GRB 091130, GRB 091130A

Y.L. Qiu, X.F. Wang, C. Wu, L.P. Xin,  J. Wang, 
J.Y. Wei, W. K. Zheng, J. S. Deng, and J. Y. Hu 
on behalf of EAFON report:

We observed the optical afterglow of GRB 091130A
(Krimm et al. GCN 10212
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 ) with Xinglong TNT telescope 
from Nov. 30th, 18:25:41 (UT), 2.27 hours after the burst. 
The weather is not good with a bright moon. 
After stacked 31*300s images, the 3 sigma upper limit 
is estimated to be R-21 mag from the SDSS magnitude, 
at the meam time of 4.2 hours after the burst.

This message may be cited.  

for more information about Xinglong GRBs Follow-up 
observations,  please visit the web-site
http://www.xinglong-naoc.org/grb/

H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), J. R. Cummings (CRESST/GSFC/UMBC),
E. Hoversten (PSU), on behalf of the Swift team.

Using the Swift/BAT data set from T-60 to T+236 sec and the
XRT data set beginning at T+58 minutes from recent telemetry
downlinks, we report that BAT trigger 356516 (reported as
possible GRB 091130A, Krimm et al, Circ 10212) is probably
not a GRB.  We base this conclusion on the low significance
in the BAT and the lack of a counterpart in the XRT.
However, we can not rule out that this is an astrophysical
event which was extended in duration in the BAT (the
original trigger was a 400-sec integration), but rapidly
fading prior to the XRT observations.

The BAT image shows a 3.5 sigma bump and the mask-weighted
light curve shows an integrated 5-sigma positive excess out
to T+236 sec.  If the source is real, it is at RA, Dec =
161.854, +11.580 deg with an uncertainty of 4.5 arcmin,
(radius, sys+stat, 90% containment). The partial coding is 97%.

In 2.57 ks of Swift-XRT photon counting mode data beginning
at T+58 minutes, we do not detect any X-ray source in the
BAT error circle to a 3 sigma upper limit count rate
of 8.0e-3 count/s. This corresponds to a  0.3-10 keV
observed flux limit of 3.1e-13 erg cm-2 s-1, assuming a
typical counts-to-flux conversion factor
of 3.9e-11 erg cm-2 count-1.

UVOT took a finding chart exposure of 150 seconds with
the White filter starting 3592 seconds after the BAT trigger.
No credible afterglow candidate has been found in the initial
data products. The 2.7'x 2.7' sub-image covers 25% of the BAT
error circle. The typical 3-sigma upper limit has been
about 19.6 mag. The 8'x8' region for the list of sources
generated on-board covers 100% of the BAT error circle.
The list of sources is typically complete to about 18 mag.
No correction has been made for the expected extinction
corresponding to E(B-V) of 0.03.

S.Sergienko, V.Yurkov
Blagoveschensk Educational State University, Blagoveschensk


E. Gorbovskoy, D. Zimnukhov, V. Lipunov, V.Kornilov, A.Belinski, 
D.Kuvshinov,  N.Shatskiy,  N.Tyurina, P.Balanutsa, V.V.Chazov,
A.Kuznetsov

Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parkhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

S.Yazev, K.Ivanov, N.M.Budnev, E.Konstantinov, V.Lenok Irkutsk State University


MASTER  robotic telescope (MASTER-Net: http://observ.pereplet.ru, D= 200 
mm, FOV= 7  square degrees, 16 Mpx Apogee CCD, testing mode) located
at Blagoveschensk   was responted to the  GRB 091130
(Krimm et al., GCN 10212
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 )   23 sec after Notice time and
7 min 22 s after the GRB time.

The first images are saturated due to the Moon light and cloudes.

After exposition correction we took several dozens succesfull images with 
limit ~14.5 mag.

   Time         T_start-T_GRB      ExpTime  m_lim

  16:43:56        35:45             60s       14.5

  16:43:56      35:45-47:03       10x60s      16

We do not see OT brighter 14 mag  in BAT error box.

The reduction is continued.

The message may be cited.
The summ of the images is available at 
http://observ.pereplet.ru/images/GRB091130/grb091130.jpeg.
We note that MASTER-Amur-Blagoveschensk are in testing mode now.

mailto: lipunov@sai.msu.ru

H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), S. Campana (INAF-OAB),
J. R. Cummings (NASA/UMBC), P.A. Curran (MSSL-UCL), V. D'Elia (ASDC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU), N. P. M. Kuin (MSSL),
V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-IASFPA),
M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC),
E. Troja (NASA/GSFC/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 16:08:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located possible GRB 091130 (trigger=377436).  Swift did not immediately slew
to this burst due to the Earth limb constraint. 
The BAT on-board calculated location is 
RA, Dec 161.881, +11.626 which is 
   RA(J2000) = 10h 47m 32s
   Dec(J2000) = +11d 37' 32"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for an image trigger, the
light curve shows no obvious burst-like structure. 

Due to an observing constraint, Swift will not slew until 
T0+49.3 minutes. There will be no XRT or UVOT data until
this time. 

Without observations by XRT or UVOT, without a clear light curve,
and with only a marginal (7.13 sigma) image, we cannot confirm
at this time that this is a true GRB.  This uncertainty will be
resolved if the XRT detects a source during its observation,
or when the full BAT data is downlinked via Malindi. 

Burst Advocate for this burst is H. A. Krimm (krimm AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)