Gamma-ray Burst 090626

(All information courtesy of the instrument teams.)

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Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 26 Jun 09 04:32:25 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      48
TRIGGER_NUM:     267683530
GRB_RA:          170.017d {+11h 20m 04s} (J2000),
                 170.131d {+11h 20m 32s} (current),
                 169.413d {+11h 17m 39s} (1950)
GRB_DEC:         -36.600d {-36d 36' 00"} (J2000),
                 -36.652d {-36d 39' 06"} (current),
                 -36.326d {-36d 19' 33"} (1950)
GRB_ERROR:       4.77 [deg radius, statistical plus systematic]
GRB_INTEN:       646 [cnts/sec]
DATA_SIGNIF:     28.30 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        15008 TJD;   177 DOY;   09/06/26
GRB_TIME:        16328.88 SOD {04:32:08.88} UT
GRB_PHI:         280.00 [deg]
GRB_THETA:        15.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.00
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:     100%  Local Particles
2nd_MOST_LIKELY:   0%  n/a
DETECTORS:       1,0,0, 1,0,0, 1,0,0, 0,0,0, 0,0,
SUN_POSTN:        95.14d {+06h 20m 34s}  +23.35d {+23d 21' 12"}
SUN_DIST:         92.63 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      143.80d {+09h 35m 12s}  +12.46d {+12d 27' 52"}
MOON_DIST:        55.02 [deg]
MOON_ILLUM:      16 [%]
GAL_COORDS:      283.18, 22.74 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      187.88,-37.04 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 188.60,-23.40 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 26 Jun 09 04:32:35 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     267683530
GRB_RA:          170.617d {+11h 22m 28s} (J2000),
                 170.732d {+11h 22m 56s} (current),
                 170.009d {+11h 20m 02s} (1950)
GRB_DEC:         -35.500d {-35d 30' 00"} (J2000),
                 -35.552d {-35d 33' 07"} (current),
                 -35.226d {-35d 13' 31"} (1950)
GRB_ERROR:       3.90 [deg radius, statistical plus systematic]
GRB_INTEN:       1617 [cnts/sec]
DATA_SIGNIF:     146.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        15008 TJD;   177 DOY;   09/06/26
GRB_TIME:        16328.88 SOD {04:32:08.88} UT
GRB_PHI:         280.00 [deg]
GRB_THETA:        15.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.00
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:     100%  Local Particles
2nd_MOST_LIKELY:   0%  n/a
DETECTORS:       1,0,0, 1,0,0, 1,0,0, 0,0,0, 0,0,
SUN_POSTN:        95.14d {+06h 20m 34s}  +23.35d {+23d 21' 12"}
SUN_DIST:         92.56 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      143.80d {+09h 35m 13s}  +12.46d {+12d 27' 49"}
MOON_DIST:        54.35 [deg]
MOON_ILLUM:      16 [%]
GAL_COORDS:      283.23, 23.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      187.74,-35.84 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 188.60,-23.40 [deg].

GCN Circular #9579
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."
GCN Circular #9584
Fred Piron (LPTA), Francesco Longo (INFN/Trieste),=20 Giulia Iafrate (INAF/OA Trieste), Teddy Cheung (NASA/GSFC),=20 Hiro Tajima (SLAC) and Valerie Connaughton (UAH) report on=20 behalf of the Fermi LAT collaboration:
Ground processing of data from the Fermi Large Area Telescope (LAT)=20 reveals that the LAT significantly detects emission from GRB 090626,=20 reported as a bright Fermi Gamma-ray Burst Monitor (GBM) burst (von=20 Kienlin GCN 9579).
The LAT localization of this burst is RA, Dec =3D 170.01, -33.50 =B1=20 0.32 deg (statistical, 95% CL), with an additional systematic error=20 estimated at 0.1 deg. There appears to be significant emission=20 above 100 MeV until about 250 s after the GBM trigger time. =20 Further information will be available following more detailed=20 analysis.
The point of contact for this burst is Fred Piron=20 (frederic.piron@lpta.in2p3.fr).
The Fermi LAT is a pair conversion telescope designed to cover the=20 energy band from 20 MeV to greater than 300 GeV. It is the product of=20 an international collaboration between NASA and DOE in the U.S. and=20 many scientific institutions across France, Italy, Japan and Sweden.
This message can be cited.
GCN Circular #9588
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, and D. Svinkin on behalf of the=20 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=20 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=20 of the Swift-BAT team, and
V. Connaughton, M.S. Briggs and C.A. Meegan on behalf of the Fermi=20 GBM team
report:=20
Suzaku-WAM, Konus-Wind, Konus-RF, Swift-BAT, Odyssey-HEND, and INTEGRAL-SPI-ACS observed the long GRB=20 090626 at about 04:32:08 UT (corresponding to the Fermi/GBM trigger 267683530/ 090626: von Kienlin, GCN 9579; also detected by=20 Fermi/LAT: Piron et al., GCN 9584). The burst was outside the=20 coded field-of-view of the Swift BAT.
Triangulation gives various annuli which are shown in the=20 figure at:
ftp://ftp.nsstc.org/outgoing/mbriggs/ipn_090626/GRB090626_IPN_v2.png.
The Konus-Wind-GBM annulus is centered at=20 RA(2000)=3D257.678 (17h 10m 43s) Dec(2000)=3D-27.309 (-27d 18' 34"), with a radius of 73.391 =B1 0.246 deg (3 sigma). The Konus-Wind-Odyssey annulus is centered at RA(2000)=3D226.080 (15h 04m 19s)=20 Dec(2000)=3D-16.554 (-16d 33' 13"), with a radius of 52.513 =B1 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), so that the IPN localization confirms the LAT location=20 and narrows it to a much smaller region.
The Konus-Wind-GBM and Konus-Wind-Odyssey IPN triangulation=20 map superimposed with the LAT location (95% CL=20 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.
GCN Circular #9595
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; Piron et al., GCN 9584; corresponding to the Fermi/GBM trigger 267683530: von Kienlin, GCN 9579) 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/
GCN Circular #9629
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) 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

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Jochen Greiner, last update: 09-Jul-2009 [Disclaimer]