GRB 140416A

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 long-duration, very intense GRB 140416A
(Fermi GBM detection: Jenke, GCN 16115
Loading...
 
 ;
IPN triangulation: Hurley at al., GCN 16116
Loading...
 
 )
triggered Konus-Wind at T0=5196.209 s UT (01:26:36.209).

The burst light curve shows multiple peaks from ~T0-24 s to ~T0+28 s.
The emission is seen up to ~8 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140416_T05196/

As observed by Konus-Wind, the burst
had a fluence of 6.9(-0.1,+0.1)x10-5 erg/cm2,
and a 64-ms peak flux, measured from T0+7.168 s,
of 1.5(-0.1,+0.1)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+32.768 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.43 (-0.06,+0.07),
the high energy photon index beta = -2.95 (-0.31,+0.18),
the peak energy Ep = 97 (-4,+4) keV,
chi2 = 88.4/96 dof.

The spectrum near the maximum count rate
(measured from T0+6.912 to T0+7.424 s)
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.78 (-0.14,+0.15),
the high energy photon index beta = -3.8 (-6.2,+0.6),
the peak energy Ep = 176 (-16,+18) keV,
chi2 = 81.5/90 dof.

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

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,

V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein,
on behalf of the Fermi GBM team,

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

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

The long-duration very intense GRB 140416A (P. Jenke, GCN Circ. 16115
Loading...
 
 ) 
has been observed by Fermi (GBM: trigger 419304403), Konus-Wind, AGILE 
(MCAL), MESSENGER (GRNS), and Mars-Odyssey (HEND), so far, at about 5201 
s UT (01:26:41).

These annuli intersect to form a long arc, whose coordinates are:
  ---------------------------------------------
     RA(2000), deg                 Dec(2000), deg
    ---------------------------------------------
    Center:
      40.186 (02h 40m 45s) +39.527 (+39d 31' 37")
    Corners:
      25.842 (01h 43m 22s) +45.226 (+45d 13' 35")
      27.972 (01h 51m 53s) +44.893 (+44d 53' 35")
      50.081 (03h 20m 20s) +30.017 (+30d 01' 02")
      50.783 (03h 23m 08s) +28.603 (+28d 36' 11")
    ---------------------------------------------
The error box area is 2.023 sq. deg, and its maximum dimension is 25.8 
deg (the minimum one is 0.164 deg).

This error box may be improved.

Because the Earth, the Wind, the Mars-Odyssey, and the MESSENGER 
satellites are nearly aligned at the moment (the angular distance 
between Wind and MESSENGER is 10.3 deg and between Wind and Mars-Odyssey 
is 170 deg), the annuli intersect at grazing incidence and the resulting 
3-sigma box is long.

The center of the GBM ground position given in P. Jenke, GCN Circ. 16115
Loading...
 
  
(that is RA, Dec, RErr = 35.4, 43.9, 1.0 deg) is 5.4 deg from the box 
center and is 1.5 deg from the center line of the Konus-MESSENGER annulus.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB140416_T05196/IPN/

P. Jenke (UAH) reports on behalf of the Fermi GBM Team:

"At 01:26:40.94 UT on April 16 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140416A (trigger 419304403/140416060).  
The GBM on-ground location, using the Fermi GBM trigger
data, is RA = 35.4, Dec = 43.9 (J2000 degrees, equivalent to 
02h 21m 36s, 43d 54'), with an uncertainty of 1 
degree (radius, 1-sigma containment,
statistical only; there is additionally a systematic error which is
currently estimated to be 2 to 3 degrees).

The angle of the burst direction to the Fermi LAT boresight is 
138 degrees.

The GBM light curve consists of several peaks with a duration
 (T90) of about 28.5 s (50-300 keV).
The time-averaged spectrum from T0-10.0 s to T0+31.0s is
well fit by a Band function with Epeak = 78 +/- 2 keV, 
Alpha = -1.01 +/- 0.04 and Beta = -2.44 +/- 0.03.

The event fluence (10-1000 keV) in this time interval is
(7.20 +/- 0.06)E-05 erg/cm^2. The 1.0-sec peak photon flux measured
starting from T0+6.4 s in the 10-1000 keV band
is 71 +/- 1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."