GRB 121011B

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,

K. Hurley on behalf of the IPN,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro,
Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM
team, and

G. Di Cocco, F. Fuschino, M. Galli, C. Labanti, and M. Marisaldi, on
behalf of the AGILE MCAL team, report:

The short GRB 121011B has been observed so far by Konus-Wind,
INTEGRAL(SPI-ACS), Suzaku(WAM) and AGILE (MCAL) at about 81143 s UT
(22:32:23).

We have triangulated the burst to a preliminary, 3 sigma error box whose
coordinates are:
    ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
     182.809 (12h 11m 14s) +44.113 (+44d 06' 47")
    Corners:
     179.176 (11h 56m 42s) +41.963 (+41d 57' 48")
     178.172 (11h 52m 41s) +41.937 (+41d 56' 14")
     187.165 (12h 28m 40s) +46.167 (+46d 10' 01")
     188.461 (12h 33m 51s) +46.130 (+46d 07' 48")
    ---------------------------------------------
The error box area is 3.43 sq. deg, and its maximum
dimension is 8.49 deg (the minimum one is 0.75 deg).

This box can be improved.

The time history and spectrum will be given in a forthcoming GCN Circular.

S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:

The short-duration hard-spectrum GRB 121011B
(IPN localization: Golenetskii at al., GCN 13863
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triggered Konus-Wind at T0=81140.083s UT (22:32:20.083)

The light curve shows a single pulse with a duration of ~0.35 s.
The emission is seen up to ~7 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB121011_T81140/

As observed by Konus-Wind the burst
had a fluence of (2.8 � 0.3)x10-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.112 s,
of (2.3 � 0.4)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst (measured T0 to T0+0.192 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.45 � 0.37,
the high energy photon index beta = -1.9 � 0.4,
the peak energy Ep = 670 � 340 keV,
chi2 = 16.3/17 dof.

All the quoted results are preliminary.

K. Takaki, Y. Hanabata,  T. Kawano, Y.Tanaka, R. Nakamura, M. Ohno,
Y. Fukazawa (Hiroshima U.),
A. Sakamoto, M. Tashiro, Y. Terada, W. Iwakiri, T. Yasuda, K. Takahara,
M. Asahina, S. Kobayashi, H. Ueno (Saitama U.),
M. Akiyama, N. Ohmori, E. Mochinaga, M. Yamauchi (Univ. of Miyazaki),
Y. E. Nakagawa (Waseda U.), S. Sugita (Nagoya U.), K. Yamaoka,
M. Kokubun, T. Takahashi (ISAS/JAXA), Y. Urata, P. Tsai (NCU), K. Nakazawa,
K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report:

The short, IPN localized GRB 121011B (Golenetskii et al., GCN 13863
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triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 22:32:22.753 UT (=T0).
The observed light curve shows  a single peak structure starting at
T0 s, ending at T0+0.5 s,  with a duration (T90) of about 0.28 seconds.
The fluence in 100 - 1000 keV was 1.21 (-0.07, +0.15) x 10^-6 erg/cm^2
The 1-s peak flux measured from T0-0.5s  was 2.10 (-0.26, +0.15)
photons/cm^2/s in the same  energy range.

Preliminary result shows that the time-averaged spectrum from T0 to
T0+0.5s is well fitted by a power-law with exponential cutoff model:
   dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
   alpha       0.45 (-0.59, +0.50), and
   Epeak       810 (-139, 229) keV (chi^2/d.o.f. = 31.1/24).

We also shows the results with the same spectrum fitted by a GRB Band
model,
the low-energy photon index alpha: -0.39 (-0.53, +0.68),
the high-energy photon index beta: <-2.33
and the peak energy Epeak: 778 (-163, +237) keV
(chi^2/d.o.f = 30.3/23).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.
The light curves for this burst are available at:

http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html