Gamma-ray Burst 090107B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 07 Jan 09 16:20:58 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     253038044
GRB_RA:          161.000d {+10h 44m 00s} (J2000),
                 161.343d {+10h 45m 22s} (current),
                 158.972d {+10h 35m 53s} (1950)
GRB_DEC:         +85.950d {+85d 57' 00"} (J2000),
                 +85.902d {+85d 54' 09"} (current),
                 +86.212d {+86d 12' 42"} (1950)
GRB_ERROR:       26.08 [deg radius, statistical plus systematic]
GRB_INTEN:       97 [cnts/sec]
DATA_SIGNIF:     5.00 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        14838 TJD;     7 DOY;   09/01/07
GRB_TIME:        58842.77 SOD {16:20:42.77} UT
GRB_PHI:         185.00 [deg]
GRB_THETA:       100.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.64
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      68%  GRB
2nd_MOST_LIKELY:  19%  Cyg X-1
DETECTORS:       0,0,0, 0,0,0, 0,0,1, 0,0,1, 0,0,
SUN_POSTN:       288.97d {+19h 15m 53s}  -22.29d {-22d 17' 30"}
SUN_DIST:        114.75 [deg]   Sun_angle= 8.5 [hr] (West of Sun)
MOON_POSTN:       55.69d {+03h 42m 45s}  +24.70d {+24d 42' 17"}
MOON_DIST:        66.46 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      125.41, 30.55 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       99.08, 64.96 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.
COMMENTS:        This trigger occurred at longitude,latitude = 119.02,21.93 [deg].

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Wed 07 Jan 09 16:21:00 UT
NOTICE_TYPE:    INTEGRAL Wakeup
TRIGGER_NUM:    5398,   Sub_Num: 0
GRB_RA:         284.8111d {+18h 59m 15s} (J2000),
                284.8439d {+18h 59m 23s} (current),
                284.6288d {+18h 58m 31s} (1950)
GRB_DEC:        +59.5941d {+59d 35' 39"} (J2000),
                +59.6070d {+59d 36' 25"} (current),
                +59.5234d {+59d 31' 24"} (1950)
GRB_ERROR:      3.00 [arcmin, radius, statistical only]
GRB_INTEN:      10.47 [sigma]
GRB_TIME:       58840.70 SOD {16:20:40.70} UT
GRB_DATE:       14838 TJD;     7 DOY;   09/01/07
SC_RA:          275.64 [deg] (J2000)
SC_DEC:          64.92 [deg] (J2000)
SUN_POSTN:      288.97d {+19h 15m 53s}  -22.29d {-22d 17' 30"}
SUN_DIST:        81.97 [deg]   Sun_angle= 0.3 [hr] (West of Sun)
MOON_POSTN:      55.69d {+03h 42m 45s}  +24.70d {+24d 42' 18"}
MOON_DIST:       86.56 [deg]
GAL_COORDS:      89.82, 22.21 [deg] galactic lon,lat of the burst
ECL_COORDS:     320.71, 80.38 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Possibly real GRB event

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 07 Jan 09 16:21:09 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      57
TRIGGER_NUM:     253038044
GRB_RA:          278.233d {+18h 32m 56s} (J2000),
                 277.324d {+18h 29m 18s} (current),
                 283.167d {+18h 52m 40s} (1950)
GRB_DEC:         +87.217d {+87d 12' 60"} (J2000),
                 +87.223d {+87d 13' 24"} (current),
                 +87.165d {+87d 09' 53"} (1950)
GRB_ERROR:       18.43 [deg radius, statistical plus systematic]
GRB_INTEN:       82 [cnts/sec]
DATA_SIGNIF:     6.30 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        14838 TJD;     7 DOY;   09/01/07
GRB_TIME:        58842.77 SOD {16:20:42.77} UT
GRB_PHI:         188.00 [deg]
GRB_THETA:       105.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.93
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      69%  GRB
2nd_MOST_LIKELY:  13%  Cyg X-1
DETECTORS:       0,0,0, 0,0,0, 0,0,1, 0,0,1, 0,0,
SUN_POSTN:       288.97d {+19h 15m 53s}  -22.29d {-22d 17' 30"}
SUN_DIST:        109.57 [deg]   Sun_angle= 0.8 [hr] (West of Sun)
MOON_POSTN:       55.69d {+03h 42m 45s}  +24.71d {+24d 42' 19"}
MOON_DIST:        67.38 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      119.81, 27.32 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       88.87, 69.31 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 119.02,21.93 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 07 Jan 09 16:21:13 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      68
TRIGGER_NUM:     253038044
GRB_RA:          288.833d {+19h 15m 20s} (J2000),
                 288.898d {+19h 15m 35s} (current),
                 288.476d {+19h 13m 54s} (1950)
GRB_DEC:         +47.100d {+47d 06' 00"} (J2000),
                 +47.116d {+47d 06' 58"} (current),
                 +47.011d {+47d 00' 39"} (1950)
GRB_ERROR:       9.03 [deg radius, statistical plus systematic]
GRB_INTEN:       173 [cnts/sec]
DATA_SIGNIF:     8.00 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        14838 TJD;     7 DOY;   09/01/07
GRB_TIME:        58842.77 SOD {16:20:42.77} UT
GRB_PHI:         193.00 [deg]
GRB_THETA:       145.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.69
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      71%  Cyg X-1
2nd_MOST_LIKELY:  25%  GRB
DETECTORS:       0,0,0, 0,0,0, 0,0,1, 0,0,1, 0,0,
SUN_POSTN:       288.97d {+19h 15m 53s}  -22.29d {-22d 17' 30"}
SUN_DIST:         69.41 [deg]   Sun_angle= 0.0 [hr] (West of Sun)
MOON_POSTN:       55.69d {+03h 42m 45s}  +24.71d {+24d 42' 19"}
MOON_DIST:        93.67 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:       78.24, 15.72 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      306.25, 68.18 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 119.02,21.93 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 07 Jan 09 16:21:44 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      67
TRIGGER_NUM:     253038044
GRB_RA:          288.890d {+19h 15m 34s} (J2000),
                 288.837d {+19h 15m 21s} (current),
                 289.181d {+19h 16m 43s} (1950)
GRB_DEC:         +74.270d {+74d 16' 12"} (J2000),
                 +74.286d {+74d 17' 10"} (current),
                 +74.179d {+74d 10' 45"} (1950)
GRB_ERROR:       8.36 [deg radius, statistical only]
DATA_SIGNIF:     9.60 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        14838 TJD;     7 DOY;   09/01/07
GRB_TIME:        58842.77 SOD {16:20:42.77} UT
GRB_PHI:         189.00 [deg]
GRB_THETA:       118.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   1 (Gnd S/W Version number)
SUN_POSTN:       288.97d {+19h 15m 53s}  -22.29d {-22d 17' 30"}
SUN_DIST:         96.58 [deg]   Sun_angle= 0.0 [hr] (West of Sun)
MOON_POSTN:       55.69d {+03h 42m 47s}  +24.71d {+24d 42' 23"}
MOON_DIST:        75.24 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      105.71, 24.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       59.25, 80.11 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 07 Jan 09 16:21:49 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     253038044
GRB_RA:           32.010d {+02h 08m 02s} (J2000),
                  34.311d {+02h 17m 15s} (current),
                  23.294d {+01h 33m 11s} (1950)
GRB_DEC:         +89.260d {+89d 15' 36"} (J2000),
                 +89.302d {+89d 18' 07"} (current),
                 +89.010d {+89d 00' 35"} (1950)
GRB_ERROR:       11.63 [deg radius, statistical only]
DATA_SIGNIF:     6.90 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        14838 TJD;     7 DOY;   09/01/07
GRB_TIME:        58842.77 SOD {16:20:42.77} UT
GRB_PHI:         189.00 [deg]
GRB_THETA:       102.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   1 (Gnd S/W Version number)
SUN_POSTN:       288.97d {+19h 15m 53s}  -22.29d {-22d 17' 30"}
SUN_DIST:        112.47 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       55.70d {+03h 42m 47s}  +24.71d {+24d 42' 23"}
MOON_DIST:        64.64 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      123.21, 26.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       88.45, 66.16 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Wed 07 Jan 09 16:21:10 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    5398,   Sub_Num: 1
GRB_RA:         284.8037d {+18h 59m 13s} (J2000),
                284.8365d {+18h 59m 21s} (current),
                284.6212d {+18h 58m 29s} (1950)
GRB_DEC:        +59.5862d {+59d 35' 10"} (J2000),
                +59.5990d {+59d 35' 56"} (current),
                +59.5154d {+59d 30' 56"} (1950)
GRB_ERROR:      2.62 [arcmin, radius, statistical only]
GRB_INTEN:      22.11 [sigma]
GRB_TIME:       58846.49 SOD {16:20:46.49} UT
GRB_DATE:       14838 TJD;     7 DOY;   09/01/07
SC_RA:          275.64 [deg] (J2000)
SC_DEC:          64.92 [deg] (J2000)
SUN_POSTN:      288.97d {+19h 15m 53s}  -22.29d {-22d 17' 30"}
SUN_DIST:        81.96 [deg]   Sun_angle= 0.3 [hr] (West of Sun)
MOON_POSTN:      55.69d {+03h 42m 45s}  +24.71d {+24d 42' 19"}
MOON_DIST:       86.57 [deg]
GAL_COORDS:      89.81, 22.21 [deg] galactic lon,lat of the burst
ECL_COORDS:     320.66, 80.37 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Possibly real GRB event

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Wed 07 Jan 09 16:23:58 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    5398,   Sub_Num: 2
GRB_RA:         284.8161d {+18h 59m 16s} (J2000),
                284.8489d {+18h 59m 24s} (current),
                284.6337d {+18h 58m 32s} (1950)
GRB_DEC:        +59.5909d {+59d 35' 27"} (J2000),
                +59.6038d {+59d 36' 14"} (current),
                +59.5202d {+59d 31' 13"} (1950)
GRB_ERROR:      2.58 [arcmin, radius, statistical only]
GRB_INTEN:      24.99 [sigma]
GRB_TIME:       58854.57 SOD {16:20:54.57} UT
GRB_DATE:       14838 TJD;     7 DOY;   09/01/07
SC_RA:          275.64 [deg] (J2000)
SC_DEC:          64.92 [deg] (J2000)
SUN_POSTN:      288.97d {+19h 15m 54s}  -22.29d {-22d 17' 29"}
SUN_DIST:        81.97 [deg]   Sun_angle= 0.3 [hr] (West of Sun)
MOON_POSTN:      55.72d {+03h 42m 52s}  +24.71d {+24d 42' 39"}
MOON_DIST:       86.57 [deg]
GAL_COORDS:      89.81, 22.20 [deg] galactic lon,lat of the burst
ECL_COORDS:     320.71, 80.37 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Possibly real GRB event

GCN Circular #8786
D. Gotz (CEA-Saclay), S.Mereghetti, A.Paizis (IASF-Milano), C. Ferrigno, V.Beckmann, M. Beck (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
A GRB lasting about 20 s has been detected by IBAS in IBIS/ISGRI data at 16:20:36 UT on January 7th. The refined coordinates (J2000) are:
```
RA = 284.8075 [degrees]
DEC= 59.5924 [degrees]
```
with an uncertainty of 1.5 arcmin (90% c.l.).
A preliminary analysis gives a peak flux in the 20-200 keV range of about 1.6 ph/cmsq/s (1-s integration time) and a fluence over the same energy range of about 1.5e-6 erg/cmsq. Both values have to be considered lower limits, since the burst is affected by telemetry saturation.
A plot of the light curve will be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
This message can be cited.

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Wed 07 Jan 09 17:17:13 UT
NOTICE_TYPE:    INTEGRAL Offline
TRIGGER_NUM:    5398,   Sub_Num: 3
GRB_RA:         284.8075d {+18h 59m 14s} (J2000),
                284.8403d {+18h 59m 22s} (current),
                284.6251d {+18h 58m 30s} (1950)
GRB_DEC:        +59.5924d {+59d 35' 32"} (J2000),
                +59.6052d {+59d 36' 19"} (current),
                +59.5216d {+59d 31' 18"} (1950)
GRB_ERROR:      1.50 [arcmin, radius, statistical only]
GRB_INTEN:      24.99 [sigma]
GRB_TIME:       58854.57 SOD {16:20:54.57} UT
GRB_DATE:       14838 TJD;     7 DOY;   09/01/07
SC_RA:          275.64 [deg] (J2000)
SC_DEC:          64.92 [deg] (J2000)
SUN_POSTN:      289.01d {+19h 16m 03s}  -22.29d {-22d 17' 12"}
SUN_DIST:        81.96 [deg]   Sun_angle= 0.3 [hr] (West of Sun)
MOON_POSTN:      56.30d {+03h 45m 13s}  +24.81d {+24d 48' 49"}
MOON_DIST:       86.68 [deg]
GAL_COORDS:      89.81, 22.21 [deg] galactic lon,lat of the burst
ECL_COORDS:     320.69, 80.38 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       refined_coordinates_after_offline_analysis

GCN Circular #8787
GRB 090107B: ROTSE-III Optical Limits
T. Guver (U Arizona), H. Swan (U Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIId, located at the TUBITAK National Observatory at Bakirlitepe, Turkey, responded to GRB 090107B (INTEGRAL trigger 5398; D. Gotz, GCN 8786), producing images beginning 0.0 s after the GCN notice time. An automated response took the first image at 16:20:40.7 UT, 4.7 s after the burst, and during the gamma-ray emission, under fair conditions. We took 10 5-sec, 10 20-sec and 63 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is on going.
Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma INTEGRAL/IBIS error circle, for both single images and coadding into sets of 10. Individual images have limiting magnitudes ranging from 16.2-16.6; we set the following specific limits.
```
start UT	end UT 	t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
16:26:35.8	16:26:55.8	20	16.6	359.8	N
16:28:03.0	16:32:41.6	278	17.7	447.0	Y
```
GCN Circular #8788
Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports via the AAVSO High Energy Network the following optical observations of the INTEGRAL burst GRB 090107B (Gotz et al., GCN Circular #8786):
Unfiltered observations were made using a 0.4-meter RC telescope with an SBIG STL-1001E CCD. The full INTEGRAL error box was observed unfiltered starting at 16:35UT, 15 minutes after the burst. Combining ten 60-second exposures, we do not see any optical afterglow to a limiting magnitude of 20.5 (compared with the DSS2 red plate).
A FITS image of this observation is available at the following URL: ftp://ftp.aavso.org/grb/ArtoOksanen_GRB090107_2454839.23238_.fits
The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network.
GCN Circular #8789
M. Perri (ASDC) and P. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift began observing the field of the INTEGRAL GRB 090107B (Gotz et al., GCN Circ. 8786) 4.2 ks after the trigger. A single uncatalogued source was identified within the IBIS/ISGRI error circle.
Using 1314 s of XRT Photon Counting mode data and 2 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 284.81750, 59.59510 which is equivalent to:
```
RA (J2000):  18 59 16.21
Dec (J2000): +59 35 42.3
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence). The source lies 21 arcsec from the IBIS/ISGRI centroid and has a count rate of ~0.25 counts/s during this observation.
Currently we cannot determine if this source is fading, and therefore cannot confirm if this source is associated with GRB 090107B. Observations of this source are on-going.
This circular is an official product of the Swift-XRT team.
GCN Circular #8790
F.E. Marshall (NASA/GSFC) reports on behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 090107B starting 4396 s after the INTEGRAL trigger (Gotz et al., GCN Circ. 8786). No optical afterglow is detected in the initial UVOT exposures at the position of the candidate X-ray afterglow (Perri et al., GCN Circ. 8789). There is also no obvious optical afterglow candidate elsewhere in the INTEGRAL error circle.
The 3-sigma upper limits in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for detecting a source at the position of the XRT candidate are:
```
Filter          T_start(s)   T_stop(s)      Exp(s)       Mag 

white             5420         5535          113        >20.9
v                 4396         4595          197        >19.6
b                 5216         5415          197        >20.3
u                 5010         5209          197        >20.1
uvw1              4806         5005          197        >20.3
uvm2              4600         4799          197        >20.3
uvw2              4191         4390          197        >20.6
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.046 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #8791
G. Stratta (ASDC), M. Perri (ASDC) and J. R. Cummings (GSFC/UMBC) report on behalf of the Swift-XRT team:
The Swift ToO observations of GRB 090107B started on 2009 Jan 7th at 17:30:50 UT. XRT data set consists of 5.7 ks exposure in PC mode. The single, uncatalogued X-ray source observed in the field of INTEGRAL, previously reported by Perri et al. (GCN Circ. 8789), shows fading flux, confirming its afterglow nature.
The 0.3-10 keV light curve from T + 4.2 ks to T + 96.4 ks possibly indicates evidence for a plateau phase followed by a steeper decay, but the available data prevented us from constraining the parameters (i.e. the temporal break and the two decay indexes). Assuming a simple power law model, the best fit decay index is alpha = 1.3 +/- 0.1.
The average spectrum accumulated in the same time interval was fitted with an absorbed power law. The best fit photon index is 1.8 +/- 0.4. The spectrum shows evidence of absorption at the level of (9 +/- 1)e20 cm-2, in excess of the estimated Galactic value (5e20 cm-2, Kalberla et al. 2005). The average observed[unabsorbed] 0.3-10 keV average flux is about 2.8[3.6]e-12 ergs cm-2 s-1.
The predicted count rate 48 hours after the trigger is 0.002 cts/s The count-rate-to-flux conversion factor is 5.2e-11 ergs cm-2 cts-1
All quoted errors are at 90% confidence level.
Burst Advocate for this burst is J. R. Cummings.
This circular is an official product of the Swift-XRT team.
GCN Circular #8793
A. Goldstein (UAH), R. Preece (UAH), and A.J. van der Horst (NASA/ORAU) report on behalf of the Fermi GBM Team:
"At 16:20:42.77 UT on 07 January 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090107B (trigger 25303844 / 090107681).
This burst was also detected by the INTEGRAL IBAS (D. Gotz et al. 2009, GCN 8786) The GBM on-ground location is consistent with the INTEGRAL position.
The GBM light curve consists of two main emission peaks and apparent substructure with a duration (T90) of about 24.1 s (8-1000 keV). The time-averaged spectrum from T0-4.1 s to T0+20.5 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -0.68 +/- 0.26 and the cutoff energy, parameterized as Epeak, is 106.1 +/- 14.8 keV (chi squared 530.4 for 486 d.o.f.).
The event fluence (8-1000 keV) in this time interval is (1.75 +/- 0.37)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.1 s in the 8-1000 keV band is 3.68 +/- 0.27 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #8794
Y. E. Nakagawa, T. Tamagawa (RIKEN), H. Hayashi, E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono (Univ. of Miyazaki), A. Endo, M. Tashiro, Y. Terada, Y. Urata, K. Onda, N. Kodaka, K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Sugita, K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira (Hiroshima U.), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report:
The long GRB 090107B (Gotz et al., GCN 8786) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2009-01-07 16:20:35 UT (=T0).
The observed light curve shows a double-peaked structure lasting from T0-1 s to T0+20 s with a duration (T90) of about 14 seconds. The fluence in 100 - 1000 keV was 1.3 (+0.7, -0.9) * 10^-6 erg/cm^2. The 1-s peak flux measured from T0+13 s was 0.4 +/- 0.3 photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-1 s to T0+20 s is well fitted by a single power-law with a photon index of 2.0 +/- 0.4 (chi^2/d.o.f = 6/10).
All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included.
The light curves with 1-sec time resolution for this burst will be appeared at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html

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Jochen Greiner, last update: 10-Jan-2009 [Disclaimer]