GRB 140308A

K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,

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

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey 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

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on
behalf of the Swift-BAT team, report:

The long-duration, intense GRB 140308A has been observed by Konus-Wind, 
Suzaku (WAM), MESSENGER (GRNS), Swift (BAT), and Mars Odyssey (HEND), so 
far, at about 13766 s UT (03:49:26). The burst was outside the coded 
field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   357.561 (23h 50m 15s) -33.348 (-33d 20' 54")
  Corners:
   357.844 (23h 51m 23s) -33.006 (-33d 00' 20")
   357.443 (23h 49m 46s) -33.802 (-33d 48' 06")
   357.271 (23h 49m 05s) -33.688 (-33d 41' 17")
   357.673 (23h 50m 42s) -32.891 (-32d 53' 28")
  ---------------------------------------------
The error box area is 549 sq. arcmin, and its maximum
dimension is 56 arcmin (the minimum one is 11 arcmin).
The Sun distance was 29.6 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB140308_T13764/IPN/

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

The bright long-duration hard-spectrum 140308A (IPN triangulation: 
Hurley et al., GCN 15941
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 ) triggered Konus-Wind at T0=13764.906 s UT 
(03:49:24.906).

The burst light curve shows a multi-peaked structure with a total 
duration of ~90 s. The emission is seen up to ~18 MeV.

As observed by Konus-Wind, the burst
had a fluence of (1.01 +/- 0.10)x10^-4 erg/cm2,
and a 256-ms peak flux, measured from T0+16.976 s,
of (8.7 +/- 1.6)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+65.024 s)
is best fit in the 26 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.81 (-0.15,+0.17),
the high energy photon index beta = -2.07 (-0.16,+0.11),
the peak energy Ep = 246 (-35, 45) keV,
chi2 = 109/97 dof.

The spectrum near the maximum count rate
(measured from T0+15.872 to T0+24.064 s)
is best fit in the 26 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.67 (-0.26,+0.29),
the high energy photon index beta = -2.06 (-0.26,+0.14),
the peak energy Ep = 228 (-43, 74) keV,
chi2 = 96/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140308_T13764/

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.

T. Nagayoshi, M. Tashiro, Y. Terada, S. Koyama, T. Yasuda, S. Takeda,
Y.���Ishida, H. Ueno, S. Sugimoto (Saitama U.),
M. Yamauchi, N. Ohmori, M. Akiyama, R. Kinoshita (Univ. of Miyazaki),
M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui,���Y. Fukazawa 
(Hiroshima U.), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.),
Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri (RIKEN), Y. Hanabata (ICRR), Y. Urata (NCU), K. Nakazawa,
K. Makishima (Univ. of Tokyo) on behalf of the Suzaku WAM team, report:

The long GRB 140308A (Konus-Wind detection: S. Golenetskii et al.,
GCN 15943
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 , IPN localization: S. Golenetskii et al., GCN 15941
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 )
was triggered the Suzaku Wide-band All-sky Monitor (WAM)
which covers an energy range of 50 keV - 5 MeV at 03:49:26.030 UT (=T0).

The observed light curve shows a multi-peaked structure starting at 
T0-10 s, ending at T0+80 s with a duration (T90) of about 64 seconds.
The fluence in 100 - 1000 keV was 4.02 (-0.78, +0.14) x10^-5 erg/cm^2.
The 1-s peak flux measured from T0+20 s was
7.71 (-5.71, +0.07) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-10 s
to T0+80 s is well fitted by a GRB Band model in 90 keV to 5 MeV.
the low-energy photon index alpha: -0.95 (-0.44, +1.11),
the high-energy photon index beta: -2.20 (-0.23, +0.14),
and the peak energy Epeak: 386 (-128, +132) keV
(chi^2/d.o.f = 24.9/25).

Due to the brightness of this burst, a 3% systematic error was added for
low energy channels. All the quoted errors are at statistical 90% 
confidence level.

The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html