GRB 090626

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

"At 04:32:08.88  UT on 26 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090626 (trigger 267683530  / 090626189).
The on-ground calculated location, using the GBM trigger data,
is RA = 169.3, DEC = -36.1 (J2000 degrees, equivalent to 11h 17m, -36d 06'),

with a statistical uncertainty of less than 1 degree 
(radius, 1-sigma containment) and an additional systematic error which 
is currently estimated to be 2 to 3 degrees. 
The angle from the Fermi LAT boresight is 15 degrees.

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

The GBM light curve consists of four main peaks with a duration (T90) 
of about 70 s (8-1000 keV). The time-averaged spectrum from 
T0-0.256 s to T0+69.377 s is best fit by a Band function with 
Epeak = 175 +/- 12 keV, alpha = -1.29 +/- 0.02, and 
beta = -1.98 +/- 0.02 (chi squared 578 for 477 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(3.5 +/- 0.1)E-05 erg/cm^2. The 1.024-sec peak photon flux measured 
starting from T0+1.024 s in the 8-1000 keV band 
is 17.9 +/- 1.4 ph/s/cm^2.

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

Fred Piron (LPTA), Francesco Longo (INFN/Trieste), 
Giulia Iafrate (INAF/OA Trieste), Teddy Cheung (NASA/GSFC), 
Hiro Tajima (SLAC) and Valerie Connaughton (UAH) report on 
behalf of the Fermi LAT collaboration:

Ground processing of data from the Fermi Large Area Telescope (LAT) 
reveals that the LAT significantly detects emission from GRB 090626, 
reported as a bright Fermi Gamma-ray Burst Monitor (GBM) burst (von 
Kienlin GCN 9579
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 ).

The LAT localization of this burst is RA, Dec = 170.01, -33.50 � 
0.32 deg (statistical, 95% CL), with an additional systematic error 
estimated at 0.1 deg.   There appears to be significant emission 
above 100 MeV until about 250 s after the GBM trigger time.  
Further information will be available following more detailed 
analysis.

The point of contact for this burst is Fred Piron 
(frederic.piron@lpta.in2p3.fr).

The Fermi LAT is a pair conversion telescope designed to cover the 
energy band from 20 MeV to greater than 300 GeV. It is the product of 
an international collaboration between NASA and DOE in the U.S. and 
many scientific institutions across France, Italy, Japan and Sweden.

This message can be cited.

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, and D. Svinkin on behalf of the 
Konus-Wind and Konus-RF teams, 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,

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

A. von Kienlin, G. Lichti, and A. Rau on behalf of the
INTEGRAL SPI-ACS GRB team,

K. Hurley, on behalf of the INTEGRAL and Odyssey teams,

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

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


report: 

Suzaku-WAM, Konus-Wind, Konus-RF, Swift-BAT, Odyssey-HEND,
and INTEGRAL-SPI-ACS observed the long GRB 
090626 at about 04:32:08 UT (corresponding to the Fermi/GBM
trigger 267683530/ 090626: von Kienlin, GCN 9579
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 ; also detected by 
Fermi/LAT: Piron et al., GCN 9584
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 ).  The burst was outside the 
coded field-of-view of the Swift BAT.

Triangulation gives various annuli which are shown in the 
figure at:

ftp://ftp.nsstc.org/outgoing/mbriggs/ipn_090626/GRB090626_IPN_v2.png.

The Konus-Wind-GBM annulus is centered at 
RA(2000)=257.678 (17h 10m 43s)  Dec(2000)=-27.309 (-27d 18' 34"), with a
radius of 73.391 � 0.246 deg (3 sigma).  The Konus-Wind-Odyssey
annulus is centered at RA(2000)=226.080 (15h 04m 19s) 
Dec(2000)=-16.554 (-16d 33' 13"), with a radius of 52.513 � 0.163 deg 
(3 sigma).

These annuli intersect to form the following 
3-sigma error box:

-----------------------------------------------
   RA(2000), deg               Dec(2000), deg
-----------------------------------------------
Center:
  170.419 (11h 21m 41s)   -33.051 (-33d 03' 04")
Corners:
  170.543 (11h 22m 10s)   -32.147 (-32d 08' 48")
  170.207 (11h 20m 50s)   -32.836 (-32d 50' 11")
  170.305 (11h 21m 13s)   -33.942 (-33d 56' 31")
  170.633 (11h 22m 32s)   -33.264 (-33d 15' 51")

-----------------------------------------------

The error box area is 0.363 sq. deg (1307.6 sq. arcmin).
This error box may be improved.


The box contains the LAT location (Piron et al., GCN 9584
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 ),
so that the IPN localization confirms the LAT location 
and narrows it to a much smaller region.

The Konus-Wind-GBM and Konus-Wind-Odyssey IPN triangulation 
map superimposed with the LAT location (95% CL 
error, statistical only) is available at 

ftp://ftp.nsstc.org/outgoing/mbriggs/ipn_090626/loc_090626_ipn_teeny.gif.

We encourage follow-up observations of the overlapping region 
between the IPN box and the LAT error circle.

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

The long bright GRB 090626 localized by IPN and Fermi/LAT (Golenetskii 
et al., GCN 9588
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 ; Piron et al., GCN 9584
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 ; corresponding to the Fermi/GBM
trigger 267683530: von Kienlin, GCN 9579
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 ) triggered Konus-Wind at 
T0(KW)=16330.962 s UT (04:32:10.962) and Konus-RF at T0(KRF)=16332.013 s 
UT (04:32:12.013).

The burst light curve shows a multipeaked structure with a duration of
~60 s

As observed by Konus-Wind the burst
had a fluence of 7.78(-1.01, +0.91)x10^-5 erg/cm2,
and a 64-ms peak flux measured from T0+21.056 s
of 1.41(-0.25, +0.24)x10^-5 erg/cm2/s
(both in the 20 keV - 7 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+61.696 s) can be fitted (in the 20 keV - 7 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -1.26(-0.08, +0.09),
the high energy photon index beta = -2.43(-0.54, +0.20),
the peak energy Ep = 202(-24, +29) keV (chi2 = 98.7/78 dof).

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

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090626_T16332/

K. Noda, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi,
K. Kono, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:


The long GRB 090626 (Fermi/GBM trigger 267683530 / 090626189 ; A. von Kienlin et al.,
GCN 9579
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 ) triggered the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 04:32:09 UT (=T0). The observed
light curve shows a multi-peaked structure lasting from T0-2 s, ending at
T0+65 s, with a duration (T90) of about 45 seconds.

The fluence in 100 - 1000 keV was 3.60 (-0.07, +0.22) x10-5 erg/cm2.
The 1-s peak flux measured from T0+2 s was 10.51 (-0.76, +0.67)
photons/cm2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-2s to T0+65s is well fitted by a power-law with exponential cutoff model:
  dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha 1.76(-0.18, +0.17), and
  Epeak 270(-79, +63) keV (chi2/d.o.f. = 26/22).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

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