GRB 110705A

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 03:37:11.94 UT on 05 July 2011, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 110705A (trigger 331529833 / 110705151).

The on-ground calculated location, using the GBM trigger 
data, is RA = 160.6, DEC = +24.0 (J2000 degrees, 
equivalent to 10h 42m, 24d 0'), with an uncertainty 
of 4.7 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 75 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of one short spike  
with a duration (T90) of about 0.2 s (50-300 keV). 
The time-averaged spectrum from T0-0.016 s to T0+0.208 s is 
best fit by a Band function with Epeak = 1010 +90/-80 keV, 
alpha = -0.17  +/- 0.07, and beta = -3.0 +0.2/-0.4.

The event fluence (10-1000 keV) in this time interval is 
(3.3 +/- 0.1)E-06 erg/cm^2. The 0.016-sec peak photon flux measured 
starting from T0+0.0 s in the 10-1000 keV band 
is 50 +/- 4 ph/s/cm^2.

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

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 Mars Odyssey and MESSENGER GRB teams,

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

J. Goldsten on behalf of the MESSENGER GRNS 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,

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

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

and

A. von Kienlin, X. Zhang, and A. Rau, on behalf of the
INTEGRAL SPI-ACS GRB team, report:

The short hard GRB 110705A (Fermi/GBM trigger 331529833: von Kienlin, 
GCN 12108
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 ) was also detected by Konus-Wind, INTEGRAL (SPI-ACS), Suzaku 
(WAM), MESSENGER (GRNS), Mars Odyssey (HEND), and Swift (BAT). The burst 
was outside the coded  field of view of the BAT.

We have triangulated it to a 3 sigma error box whose coordinates are:
-----------------------------------------------
    RA(2000), deg              Dec(2000), deg
-----------------------------------------------
Center:
  156.024 (10h 24m 06s)   +40.099 (+40d 05' 56")
Corners:
  155.925 (10h 23m 42s)   +39.620 (+39d 37' 11")
  156.230 (10h 24m 55s)   +40.438 (+40d 26' 16")
  156.122 (10h 24m 29s)   +40.574 (+40d 34' 26")
  155.820 (10h 23m 17s)   +39.759 (+39d 45' 31")
-----------------------------------------------

The error box area is 354 sq. arcmin.
The maximum distance between the box corners is 0.97 deg.
This error box may be improved.

The GBM location (von Kienlin, GCN 12108
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 ) is 16.6 deg from the center of 
the IPN box.

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 hard GRB 110705A (Fermi/GBM trigger 331529833 / 110705151:
von Klienin, GCN 12108
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 ; localized by IPN: Golenetskii et al., GCN 12110
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 )
triggered Konus-Wind at T0=13029.942s UT (03:37:09.942)

The burst light curve shows double-peaked pulse
with a total duration of ~0.25 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/GRB110705_T13029/

As observed by Konus-Wind the burst
had a fluence of (6.0 � 1.0)x10-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.144 s,
of (3.7 � 0.9)x10-5 erg/cm2/s
(both in the 20 keV - 5 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+0.256 s) is best fitted
in the 20 keV - 5 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.14 (-0.28, +0.37),
the high energy photon index beta = -2.7 (<-2.1),
the peak energy Ep = 820(-146, +205) keV,
chi2 = 20.9/30 dof.

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

T. Yasuda, Y. Terada, M. Tashiro, W. Iwakiri, K. Takahara (Saitama U.),
T. Uehara, Y. Hanabata, T. Takahashi, M. Mizuno, M. Ohno, Y. Fukazawa
(Hiroshima U.), S. Sugita (Nagoya U.), K. Yamaoka (Aoyama Gakuin U.),
M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), N.
Ohmori, M. Akiyama, M. Yamauchi (Univ.of Miyazaki), Y. Urata, P. Tsai,
C-J. Chuang (NCU), K. Nakazawa, K. Makishima (Univ.of Tokyo), on behalf
of the Suzaku WAM team, report:

The short GRB 110705A (Fermi Gamma-Ray Burst Monitor trigger 331529833,
GCN12108
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 ; von Kienlin et al.) triggered the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at
03:37:11.933 UT (=T0).

The observed light curve shows double-peaked structure starting at
T0+0.008s, ending at T0+0.258s with a duration (T90) of about 0.25
seconds. The fluence in 100 - 1000 keV was
2.31(+0.10/-0.13) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0
was 4.24 (+0.19/-0.20) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0 to
T0+1s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha of
0.30 (+0.18/-0.10), and Epeak of 1030 (+139/-113) keV
(chi^2/d.o.f. = 45/53).

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