Gamma-ray Burst 170808B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:28:07 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     523924068
GRB_RA:          153.833d {+10h 15m 20s} (J2000),
                 154.066d {+10h 16m 16s} (current),
                 153.171d {+10h 12m 41s} (1950)
GRB_DEC:          +9.900d {+09d 54' 00"} (J2000),
                  +9.812d {+09d 48' 43"} (current),
                 +10.149d {+10d 08' 57"} (1950)
GRB_ERROR:       18.17 [deg radius, statistical plus systematic]
GRB_INTEN:       398 [cnts/sec]
DATA_SIGNIF:     13.10 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          19.00 [deg]
GRB_THETA:        55.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.81
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       0,1,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       139.01d {+09h 16m 02s}  +15.87d {+15d 52' 23"}
SUN_DIST:         15.87 [deg]   Sun_angle= -1.0 [hr] (East of Sun)
MOON_POSTN:      332.65d {+22h 10m 35s}  -11.78d {-11d 46' 37"}
MOON_DIST:       177.59 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      230.46, 49.42 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      152.16, -0.86 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 206.33,18.33 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:28:16 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     523924068
GRB_RA:           61.467d {+04h 05m 52s} (J2000),
                  61.136d {+04h 04m 33s} (current),
                  62.431d {+04h 09m 44s} (1950)
GRB_DEC:         -81.233d {-81d 13' 59"} (J2000),
                 -81.186d {-81d 11' 09"} (current),
                 -81.364d {-81d 21' 50"} (1950)
GRB_ERROR:       3.28 [deg radius, statistical plus systematic]
GRB_INTEN:       13234 [cnts/sec]
DATA_SIGNIF:     298.80 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          24.00 [deg]
GRB_THETA:       155.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.49
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      91%  GRB
2nd_MOST_LIKELY:   4%  Distant Particles
DETECTORS:       0,1,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       139.01d {+09h 16m 02s}  +15.87d {+15d 52' 23"}
SUN_DIST:        103.85 [deg]   Sun_angle= 5.2 [hr] (West of Sun)
MOON_POSTN:      332.65d {+22h 10m 36s}  -11.78d {-11d 46' 36"}
MOON_DIST:        78.13 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      295.12,-32.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      285.08,-73.74 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 206.33,18.33 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:28:19 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     523924068
GRB_RA:          146.000d {+09h 44m 00s} (J2000),
                 146.235d {+09h 44m 56s} (current),
                 145.333d {+09h 41m 20s} (1950)
GRB_DEC:          +9.580d {+09d 34' 48"} (J2000),
                  +9.499d {+09d 29' 55"} (current),
                  +9.810d {+09d 48' 36"} (1950)
GRB_ERROR:       3.56 [deg radius, statistical only]
DATA_SIGNIF:     42.00 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          10.00 [deg]
GRB_THETA:        57.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       139.01d {+09h 16m 02s}  +15.87d {+15d 52' 23"}
SUN_DIST:          9.50 [deg]   Sun_angle= -0.5 [hr] (East of Sun)
MOON_POSTN:      332.65d {+22h 10m 36s}  -11.78d {-11d 46' 36"}
MOON_DIST:       173.30 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      225.42, 42.53 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      145.01, -3.82 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_523924068.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:28:26 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      71
TRIGGER_NUM:     523924068
GRB_RA:           60.867d {+04h 03m 28s} (J2000),
                  60.566d {+04h 02m 16s} (current),
                  61.745d {+04h 06m 59s} (1950)
GRB_DEC:         -80.800d {-80d 47' 59"} (J2000),
                 -80.752d {-80d 45' 06"} (current),
                 -80.934d {-80d 56' 00"} (1950)
GRB_ERROR:       3.25 [deg radius, statistical plus systematic]
GRB_INTEN:       22059 [cnts/sec]
DATA_SIGNIF:     508.70 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          24.00 [deg]
GRB_THETA:       155.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.60
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      92%  GRB
2nd_MOST_LIKELY:   4%  Distant Particles
DETECTORS:       0,1,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       139.01d {+09h 16m 02s}  +15.87d {+15d 52' 23"}
SUN_DIST:        103.83 [deg]   Sun_angle= 5.2 [hr] (West of Sun)
MOON_POSTN:      332.65d {+22h 10m 36s}  -11.78d {-11d 46' 35"}
MOON_DIST:        78.04 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      294.78,-33.05 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      286.40,-73.99 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 206.33,18.33 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:29:16 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      3
TRIGGER_NUM:     523924068
GRB_RA:          146.270d {+09h 45m 05s} (J2000),
                 146.506d {+09h 46m 01s} (current),
                 145.600d {+09h 42m 24s} (1950)
GRB_DEC:         +10.560d {+10d 33' 36"} (J2000),
                 +10.478d {+10d 28' 42"} (current),
                 +10.791d {+10d 47' 26"} (1950)
GRB_ERROR:       1.71 [deg radius, statistical only]
DATA_SIGNIF:     60.90 [sigma]
DATA_INTERVAL:   12.288 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          10.00 [deg]
GRB_THETA:        56.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41531 (Gnd S/W Version number)
SUN_POSTN:       139.01d {+09h 16m 03s}  +15.87d {+15d 52' 22"}
SUN_DIST:          9.07 [deg]   Sun_angle= -0.5 [hr] (East of Sun)
MOON_POSTN:      332.66d {+22h 10m 38s}  -11.77d {-11d 46' 27"}
MOON_DIST:       173.83 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      224.41, 43.22 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      144.94, -2.81 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_523924068.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:29:20 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      5
TRIGGER_NUM:     523924068
GRB_RA:          146.010d {+09h 44m 02s} (J2000),
                 146.245d {+09h 44m 59s} (current),
                 145.343d {+09h 41m 22s} (1950)
GRB_DEC:          +9.590d {+09d 35' 24"} (J2000),
                  +9.509d {+09d 30' 31"} (current),
                  +9.820d {+09d 49' 12"} (1950)
GRB_ERROR:       1.15 [deg radius, statistical only]
DATA_SIGNIF:     185.90 [sigma]
DATA_INTERVAL:   14.336 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          10.00 [deg]
GRB_THETA:        57.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41531 (Gnd S/W Version number)
SUN_POSTN:       139.01d {+09h 16m 03s}  +15.87d {+15d 52' 22"}
SUN_DIST:          9.50 [deg]   Sun_angle= -0.5 [hr] (East of Sun)
MOON_POSTN:      332.66d {+22h 10m 38s}  -11.77d {-11d 46' 27"}
MOON_DIST:       173.30 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      225.41, 42.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      145.02, -3.81 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_523924068.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:29:24 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      4
TRIGGER_NUM:     523924068
GRB_RA:          146.010d {+09h 44m 02s} (J2000),
                 146.245d {+09h 44m 59s} (current),
                 145.343d {+09h 41m 22s} (1950)
GRB_DEC:          +9.590d {+09d 35' 24"} (J2000),
                  +9.509d {+09d 30' 31"} (current),
                  +9.820d {+09d 49' 12"} (1950)
GRB_ERROR:       1.07 [deg radius, statistical only]
DATA_SIGNIF:     126.00 [sigma]
DATA_INTERVAL:   13.312 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          10.00 [deg]
GRB_THETA:        57.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41531 (Gnd S/W Version number)
SUN_POSTN:       139.01d {+09h 16m 03s}  +15.87d {+15d 52' 22"}
SUN_DIST:          9.50 [deg]   Sun_angle= -0.5 [hr] (East of Sun)
MOON_POSTN:      332.66d {+22h 10m 38s}  -11.77d {-11d 46' 26"}
MOON_DIST:       173.30 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      225.41, 42.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      145.02, -3.81 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_523924068.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 08 Aug 17 22:29:44 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      8
TRIGGER_NUM:     523924068
GRB_RA:          146.500d {+09h 46m 00s} (J2000),
                 146.736d {+09h 46m 57s} (current),
                 145.828d {+09h 43m 19s} (1950)
GRB_DEC:         +11.500d {+11d 30' 00"} (J2000),
                 +11.418d {+11d 25' 05"} (current),
                 +11.731d {+11d 43' 53"} (1950)
GRB_ERROR:       1.00 [deg radius, statistical only]
DATA_SIGNIF:     384.10 [sigma]
DATA_INTERVAL:   23.552 [sec]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.10 SOD {22:27:43.10} UT
GRB_PHI:          10.00 [deg]
GRB_THETA:        55.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41531 (Gnd S/W Version number)
SUN_POSTN:       139.01d {+09h 16m 03s}  +15.87d {+15d 52' 22"}
SUN_DIST:          8.73 [deg]   Sun_angle= -0.5 [hr] (East of Sun)
MOON_POSTN:      332.66d {+22h 10m 39s}  -11.77d {-11d 46' 24"}
MOON_DIST:       174.18 [deg]
MOON_ILLUM:      99 [%]
GAL_COORDS:      223.39, 43.85 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      144.84, -1.85 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170808936/quicklook/glg_lc_medres34_bn170808936.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_523924068.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN Circular #21429
P Veres and C Meegan (both UAH) report on behalf of the Fermi GBM Team:
"At 22:27:43.10 UT on 8 August 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170808B (trigger 523924068 / 170808936).
The on-ground calculated location, using the GBM trigger data, is RA = 146.49, DEC = -2.96 (J2000 degrees, equivalent to 09 h 46 m, -02 d 58 '), with an uncertainty of 1 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).
This burst was also independently detected by INTEGRAL SPI-ACS.
The trigger resulted in an Autonomous Repoint Request (ARR) by the GBM Flight Software owing to the high fluence of the GRB. This ARR was accepted and the spacecraft slewed to the GBM in-flight location. The initial angle from the Fermi LAT boresight to the GBM ground best location is 69 degrees.
The GBM light curve shows multiple overlapping pulses with a duration (T90) of about 17.7 s (50-300 keV). The time-averaged spectrum from T0 to T0+27.1 s is best fit by a Band function with Epeak = 262 +/- 5 keV, alpha = -1.01+/- 0.01, and beta = -2.30 +/- 0.03.
The event fluence (10-1000 keV) in this time interval is (1.176 +/- 0.005)E-4 erg/cm^2. The 1-sec peak photon flux measured starting from T0+15.9 s in the 10-1000 keV band is 169.4 +/- 0.7 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."

GCN Notice

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 09 Aug 17 05:26:34 UT
NOTICE_TYPE:     Fermi-LAT Offline Position
TRIGGER_NUM:     523924068
GRB_RA:          145.660d {+09h 42m 38s} (J2000), 
                 145.888d {+09h 43m 33s} (current),
                 145.013d {+09h 40m 03s} (1950)
GRB_DEC:          +2.180d {+02d 10' 48"} (J2000),
                  +2.099d {+02d 05' 56"} (current),
                  +2.409d {+02d 24' 32"} (1950)
GRB_ERROR:       20.40 [arcmin radius, 90% containment, statistical only]
GRB_DATE:        17973 TJD;   220 DOY;   17/08/08
GRB_TIME:        80863.09 SOD {22:27:43.09} UT
TRIGGER_ID:      0x0
MISC:            0x40000000
SUN_POSTN:       139.29d {+09h 17m 09s}  +15.79d {+15d 47' 22"}
SUN_DIST:         15.16 [deg]   Sun_angle= -0.4 [hr] (East of Sun)
MOON_POSTN:      336.30d {+22h 25m 12s}  -10.77d {-10d 46' 06"} 
MOON_DIST:       166.51 [deg]  
MOON_ILLUM:      98 [%]
GAL_COORDS:      233.54, 38.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      147.17,-10.91 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi LAT Offline position.
COMMENTS:        This Notice was ground-generated -- not flight-generated.
COMMENTS:        It is the result of human-in-the-loop processing.
COMMENTS:        This is a human generated position of a LAT ground detection.
COMMENTS:        This source corresponds to GBM trigger.

GCN Circular #21430
F. Longo (University and INFN, Trieste) and D. Kocevski (NASA MSFC) report on behalf of the Fermi-LAT team: At 22:27:43.10 UT on August 08, 2017, Fermi-LAT detected high-energy emission from GRB 170808B, which was also detected by Fermi-GBM (Veres and Meegan GCN 21429). The best LAT on-ground location is found to be
RA, Dec 145.66, 2.18 deg, J2000
with an error radius of 0.34 deg (90% containment, statistical error only). This was 69 deg from the LAT boresight at the time of the trigger and triggered an autonomous repoint of the spacecraft.
The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM detection with high significance.
The highest-energy photon is a 1.62 GeV event which is observed 162 seconds after the GBM trigger.
A Swift ToO has been requested for this burst. The Fermi-LAT point of contact for this burst is Francesco Longo (francesco.longo@ts.infn.it).
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.
GCN Circular #21447
A.Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration, very bright GRB 170808B (Fermi GBM observation: Veres et al., GCN 21429; Fermi LAT Detection: Longo et al., GCN 21430) triggered Konus-Wind at T0=80859.187 s UT (22:27:39.187).
The burst light curve shows a double-peaked structure which starts at ~T0-2.3 s and has a total duration of ~18.5 s. The emission is seen up to ~10 MeV.
As observed by Konus-Wind, the burst had a fluence of 2.20(-0.08,+0.08)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+15.008 s, of 7.54(-1.02,+1.03)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst (measured from T0 to T0+23.808 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.92(-0.06,+0.07), the high energy photon index beta = -2.33(-0.09,+0.07), the peak energy Ep = 238(-16,+17) keV (chi2 = 96/98 dof)
The spectrum near the maximum count rate (measured from T0+14.848 to T0+15.616 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.52(-0.12,+0.13), the high energy photon index beta = -2.45(-0.13,+0.10), the peak energy Ep = 282(-26,+29) keV (chi2 = 80/67 dof)
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170808_T80859/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.

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Jochen Greiner, last update: 10-Aug-2017 [Disclaimer]