GRB 111016B

K. Hurley, on behalf of the Mars Odyssey and MESSENGER GRB teams,

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

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

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

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

D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, and W.
Hajdas, on behalf of the RHESSI GRB team,

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

The long-duration, intense GRB 111016B was observed by Konus-Wind, Mars 
Odyssey (HEND), MESSENGER (GRNS), RHESSI, and Swift (BAT) (outside the 
coded field of view) at 81700 s UT (22:41:40). We have triangulated it 
to a preliminary, 3 sigma error box whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   290.499 (19h 22m 00s)  -4.578 ( -4d 34' 39")
  Corners:
   290.322 (19h 21m 17s)  -4.416 ( -4d 24' 56")
   290.513 (19h 22m 03s)  -4.048 ( -4d 02' 53")
   290.676 (19h 22m 42s)  -4.740 ( -4d 44' 24")
   290.487 (19h 21m 57s)  -5.119 ( -5d 07' 09")
  ---------------------------------------------

The error box area is 696 sq. arcmin, and its maximum
dimension is 64 arcmin.

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 long hard intense GRB 111016B
(localized by IPN: Hurley et al., GCN 12452
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triggered Konus-Wind at T0=81700.723s UT (22:41:40.723)

The light curve shows a multi-peaked complex with
a total duration of ~150 s.
The emission is seen up to ~5 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB111016_T81700/

As observed by Konus-Wind the burst
had a fluence of 1.37(-0.05,+0.05)x10-4 erg/cm2,
and a 256-ms peak flux, measured from T0+1.792 s,
of 3.7(-0.3,+0.3)x10-6 erg/cm2/s
(both in the 20 keV - 5 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+145.408 s)
is best fitted in the 20 keV - 5 MeV range
by a power law with exponential cutoff model, for which
alpha = -0.78 (-0.06, +0.06),
and Ep = 378(-19, +21) keV,
chi2 = 58.7/76 dof.
Fitting this spectrum by the GRB (Band) function yields
the same alpha and Ep with a high energy photon index
beta < -3.0 (chi2 = 58.7/75 dof).

The spectrum at the maximum count rate
(measured from T0 to T0+6.144 s)
is best fitted in the 20 keV - 5 MeV range
by a power law with exponential cutoff model, for which
alpha = -0.72 (-0.10, +0.11),
and Ep = 327(-26, +30) keV,
chi2 = 86.4/76 dof.

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