Gamma-ray Burst 170803A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:30:40 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     766081,   Seg_Num: 0
GRB_RA:          174.950d {+11h 39m 48s} (J2000),
                 175.173d {+11h 40m 41s} (current),
                 174.317d {+11h 37m 16s} (1950)
GRB_DEC:         -16.311d {-16d 18' 38"} (J2000),
                 -16.408d {-16d 24' 29"} (current),
                 -16.034d {-16d 02' 00"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       673 [cnts]    Image_Peak=109 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10418     E_range: 25-100 keV
BKG_INTEN:       23346 [cnts]
BKG_TIME:        63012.52 SOD {17:30:12.52} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17968 TJD;   215 DOY;   17/08/03
GRB_TIME:        63026.92 SOD {17:30:26.92} UT
GRB_PHI:          -9.75 [deg]
GRB_THETA:        26.28 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     32.60 [sigma]
IMAGE_SIGNIF:    10.73 [sigma]
MERIT_PARAMS:     +1  +0  +0  -4  +2  +0  +0  +0 -61  +0 
SUN_POSTN:       134.03d {+08h 56m 06s}  +17.31d {+17d 18' 44"}
SUN_DIST:         52.73 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.36d {+17h 45m 26s}  -18.90d {-18d 53' 56"}
MOON_DIST:        85.83 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.04, 43.21 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      182.05,-16.93 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 248.09,-17.77 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(1.0<100sec) coincident with the FERMI_GBM event (trignum=523474232).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:30:58 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     523474232
GRB_RA:          182.717d {+12h 10m 52s} (J2000),
                 182.943d {+12h 11m 46s} (current),
                 182.074d {+12h 08m 18s} (1950)
GRB_DEC:         -13.100d {-13d 05' 59"} (J2000),
                 -13.198d {-13d 11' 51"} (current),
                 -12.822d {-12d 49' 18"} (1950)
GRB_ERROR:       5.98 [deg radius, statistical plus systematic]
GRB_INTEN:       612 [cnts/sec]
DATA_SIGNIF:     31.60 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        17968 TJD;   215 DOY;   17/08/03
GRB_TIME:        63027.11 SOD {17:30:27.11} UT
GRB_PHI:         329.00 [deg]
GRB_THETA:        40.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.86
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      98%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       0,1,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       134.03d {+08h 56m 06s}  +17.31d {+17d 18' 44"}
SUN_DIST:         57.12 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      266.36d {+17h 45m 27s}  -18.90d {-18d 53' 57"}
MOON_DIST:        79.66 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      287.90, 48.58 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      187.76,-10.93 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170803729/quicklook/glg_lc_medres34_bn170803729.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 17.50,-5.93 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=766081).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:31:05 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     523474232
GRB_RA:          181.510d {+12h 06m 02s} (J2000),
                 181.736d {+12h 06m 57s} (current),
                 180.868d {+12h 03m 28s} (1950)
GRB_DEC:         -16.830d {-16d 49' 47"} (J2000),
                 -16.928d {-16d 55' 39"} (current),
                 -16.552d {-16d 33' 05"} (1950)
GRB_ERROR:       3.74 [deg radius, statistical only]
DATA_SIGNIF:     32.30 [sigma]
DATA_INTERVAL:   1.024 [sec]
GRB_DATE:        17968 TJD;   215 DOY;   17/08/03
GRB_TIME:        63027.11 SOD {17:30:27.11} UT
GRB_PHI:         333.00 [deg]
GRB_THETA:        37.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       134.03d {+08h 56m 06s}  +17.31d {+17d 18' 44"}
SUN_DIST:         58.13 [deg]   Sun_angle= -3.2 [hr] (East of Sun)
MOON_POSTN:      266.36d {+17h 45m 27s}  -18.90d {-18d 53' 57"}
MOON_DIST:        79.68 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      287.57, 44.68 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      188.23,-14.81 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170803729/quicklook/glg_lc_medres34_bn170803729.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_523474232.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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=766081).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:34:12 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     766081,   Seg_Num: 0
GRB_RA:          174.950d {+11h 39m 48s} (J2000),
                 175.173d {+11h 40m 41s} (current),
                 174.317d {+11h 37m 16s} (1950)
GRB_DEC:         -16.311d {-16d 18' 38"} (J2000),
                 -16.408d {-16d 24' 29"} (current),
                 -16.034d {-16d 02' 00"} (1950)
GRB_DATE:        17968 TJD;   215 DOY;   17/08/03
GRB_TIME:        63027.17 SOD {17:30:27.17} UT
TRIGGER_INDEX:   10418
GRB_PHI:          -9.75 [deg]
GRB_THETA:        26.28 [deg]
DELTA_TIME:      -23.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     32.60 [sigma]
IMAGE_SIGNIF:    10.73 [sigma]
LC_URL:          sw00766081000msb.lc
SUN_POSTN:       134.03d {+08h 56m 07s}  +17.31d {+17d 18' 42"}
SUN_DIST:         52.73 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.39d {+17h 45m 33s}  -18.90d {-18d 54' 04"}
MOON_DIST:        85.86 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.04, 43.21 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      182.05,-16.93 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 248.09,-17.77 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:35:38 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     766081,   Seg_Num: 0
GRB_RA:          174.9353d {+11h 39m 44.47s} (J2000),
                 175.1582d {+11h 40m 37.96s} (current),
                 174.3024d {+11h 37m 12.56s} (1950)
GRB_DEC:         -16.3114d {-16d 18' 41.0"} (J2000),
                 -16.4090d {-16d 24' 32.2"} (current),
                 -16.0342d {-16d 02' 03.2"} (1950)
GRB_ERROR:       3.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63147.00 SOD {17:32:27.00} UT,   120.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       134.03d {+08h 56m 07s}  +17.31d {+17d 18' 41"}
SUN_DIST:         52.72 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.40d {+17h 45m 36s}  -18.90d {-18d 54' 07"}
MOON_DIST:        85.88 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.03, 43.21 [deg] galactic lon,lat of the burst
ECL_COORDS:      182.04,-16.94 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:37:01 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.294d {-16d 17' 39"} (J2000)
POINT_ROLL:      307.998d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63115.18 SOD {17:31:55.18} UT,   88.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.964
N_STARS:         25
X_OFFSET:        329 [pixels]
Y_OFFSET:        616 [pixels]
X_MAX:           1288 [pixels]
Y_MAX:           1575 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw00766081000msufc0088.fits
SUN_POSTN:       134.03d {+08h 56m 07s}  +17.31d {+17d 18' 40"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.41d {+17h 45m 39s}  -18.90d {-18d 54' 10"}
MOON_DIST:        85.90 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:37:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.294d {-16d 17' 39"} (J2000)
POINT_ROLL:      307.998d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63115.18 SOD {17:31:55.18} UT,   88.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.964
N_STARS:         25
X_OFFSET:        329 [pixels]
Y_OFFSET:        616 [pixels]
X_MAX:           1288 [pixels]
Y_MAX:           1575 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw00766081000msufc0088.fits
SUN_POSTN:       134.03d {+08h 56m 07s}  +17.31d {+17d 18' 40"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.42d {+17h 45m 40s}  -18.90d {-18d 54' 11"}
MOON_DIST:        85.90 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:39:22 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.294d {-16d 17' 39"} (J2000)
ROLL:            307.998d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63115.18 SOD {17:31:55.18} UT,   88.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     523474334
X_OFFSET:        648 [pixels]
Y_OFFSET:        935 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       808
Y_GRB_POS:       1095
BINNING_INDEX:   1
IM_URL:          sw00766081000msuni0108.fits
SUN_POSTN:       134.03d {+08h 56m 08s}  +17.31d {+17d 18' 38"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.43d {+17h 45m 44s}  -18.90d {-18d 54' 15"}
MOON_DIST:        85.92 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:39:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.294d {-16d 17' 39"} (J2000)
ROLL:            307.998d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63115.18 SOD {17:31:55.18} UT,   88.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     523474334
X_OFFSET:        648 [pixels]
Y_OFFSET:        935 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       808
Y_GRB_POS:       1095
BINNING_INDEX:   1
IM_URL:          sw00766081000msuni0108.fits
SUN_POSTN:       134.03d {+08h 56m 08s}  +17.31d {+17d 18' 38"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.44d {+17h 45m 45s}  -18.90d {-18d 54' 16"}
MOON_DIST:        85.92 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:40:40 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     766081,   Seg_Num: 0
GRB_RA:          174.9338d {+11h 39m 44.11s} (J2000),
                 175.1567d {+11h 40m 37.60s} (current),
                 174.3009d {+11h 37m 12.20s} (1950)
GRB_DEC:         -16.3105d {-16d 18' 37.8"} (J2000),
                 -16.4081d {-16d 24' 28.9"} (current),
                 -16.0333d {-16d 01' 59.9"} (1950)
GRB_ERROR:       0.8 [arcsec radius, statistical only]
GRB_MAG:         18.12 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63112.00 SOD {17:31:52.00} UT,   85.1 [sec] since BAT Trigger Time
SUN_POSTN:       134.03d {+08h 56m 08s}  +17.31d {+17d 18' 37"}
SUN_DIST:         52.71 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.45d {+17h 45m 47s}  -18.91d {-18d 54' 18"}
MOON_DIST:        85.92 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.21 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      182.03,-16.94 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN Circular #21405
S. J. LaPorte (PSU), A. Cholden-Brown (PSU), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 17:30:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170803A (trigger=766081). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 174.950, -16.311 which is
```
   RA(J2000) = 11h 39m 48s
   Dec(J2000) = -16d 18' 38"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiple-peaked structure with a duration of about 5 sec. The peak count rate was ~15000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 17:32:27.0 UT, 120.1 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 174.93532, -16.31155 which is
```
equivalent to:
   RA(J2000)  = 11h 39m 44.48s
```
Dec(J2000) = -16d 18' 41.6" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 50 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (3.54 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3 (+2.47/-2.15) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 88 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	11:39:44.11 = 174.93381
  DEC(J2000) = -16:18:37.9  = -16.31052
```
with a 90%-confidence error radius of about 0.75 arc sec. This position is 6.1 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.12 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04.
Burst Advocate for this burst is S. J. LaPorte (extragsam AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:45:55 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.933d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
POINT_ROLL:      308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63327.44 SOD {17:35:27.44} UT,   300.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.944
N_STARS:         38
X_OFFSET:        89 [pixels]
Y_OFFSET:        376 [pixels]
X_MAX:           1528 [pixels]
Y_MAX:           1815 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00766081000msufc0300.fits
SUN_POSTN:       134.04d {+08h 56m 09s}  +17.31d {+17d 18' 34"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.49d {+17h 45m 58s}  -18.91d {-18d 54' 29"}
MOON_DIST:        85.97 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:46:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.933d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
POINT_ROLL:      308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63327.44 SOD {17:35:27.44} UT,   300.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.944
N_STARS:         38
X_OFFSET:        89 [pixels]
Y_OFFSET:        376 [pixels]
X_MAX:           1528 [pixels]
Y_MAX:           1815 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00766081000msufc0300.fits
SUN_POSTN:       134.04d {+08h 56m 09s}  +17.31d {+17d 18' 34"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.49d {+17h 45m 58s}  -18.91d {-18d 54' 30"}
MOON_DIST:        85.97 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:47:21 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.933d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
ROLL:            308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63327.44 SOD {17:35:27.44} UT,   300.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     523474546
X_OFFSET:        648 [pixels]
Y_OFFSET:        935 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       808
Y_GRB_POS:       1095
BINNING_INDEX:   1
IM_URL:          sw00766081000msuni0320.fits
SUN_POSTN:       134.04d {+08h 56m 09s}  +17.31d {+17d 18' 33"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.50d {+17h 46m 01s}  -18.91d {-18d 54' 32"}
MOON_DIST:        85.98 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:47:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.933d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
ROLL:            308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63327.44 SOD {17:35:27.44} UT,   300.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     523474546
X_OFFSET:        648 [pixels]
Y_OFFSET:        935 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       808
Y_GRB_POS:       1095
BINNING_INDEX:   1
IM_URL:          sw00766081000msuni0320.fits
SUN_POSTN:       134.04d {+08h 56m 09s}  +17.31d {+17d 18' 33"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.50d {+17h 46m 01s}  -18.91d {-18d 54' 33"}
MOON_DIST:        85.98 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:46:32 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     766081,   Seg_Num: 0
GRB_RA:          174.9337d {+11h 39m 44.08s} (J2000),
                 175.1566d {+11h 40m 37.57s} (current),
                 174.3008d {+11h 37m 12.18s} (1950)
GRB_DEC:         -16.3105d {-16d 18' 37.8"} (J2000),
                 -16.4081d {-16d 24' 28.9"} (current),
                 -16.0333d {-16d 01' 59.9"} (1950)
GRB_ERROR:       2.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63147.00 SOD {17:32:27.00} UT,   120.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       134.04d {+08h 56m 09s}  +17.31d {+17d 18' 33"}
SUN_DIST:         52.71 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.50d {+17h 45m 59s}  -18.91d {-18d 54' 31"}
MOON_DIST:        85.97 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.21 [deg] galactic lon,lat of the burst
ECL_COORDS:      182.03,-16.94 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:50:26 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
POINT_ROLL:      308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63904.23 SOD {17:45:04.23} UT,   877.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.826
N_STARS:         62
X_OFFSET:        89 [pixels]
Y_OFFSET:        376 [pixels]
X_MAX:           1528 [pixels]
Y_MAX:           1815 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    11
SL_URL:          sw00766081000msufc0877.fits
SUN_POSTN:       134.04d {+08h 56m 09s}  +17.31d {+17d 18' 31"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.53d {+17h 46m 07s}  -18.91d {-18d 54' 39"}
MOON_DIST:        86.00 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:50:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
POINT_ROLL:      308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63904.23 SOD {17:45:04.23} UT,   877.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.826
N_STARS:         62
X_OFFSET:        89 [pixels]
Y_OFFSET:        376 [pixels]
X_MAX:           1528 [pixels]
Y_MAX:           1815 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    11
SL_URL:          sw00766081000msufc0877.fits
SUN_POSTN:       134.04d {+08h 56m 10s}  +17.31d {+17d 18' 31"}
SUN_DIST:         52.70 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.53d {+17h 46m 08s}  -18.91d {-18d 54' 39"}
MOON_DIST:        86.00 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:52:27 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
ROLL:            308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63904.23 SOD {17:45:04.23} UT,   877.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     523475123
X_OFFSET:        648 [pixels]
Y_OFFSET:        935 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       808
Y_GRB_POS:       1095
BINNING_INDEX:   1
IM_URL:          sw00766081000msuni0897.fits
SUN_POSTN:       134.04d {+08h 56m 10s}  +17.31d {+17d 18' 30"}
SUN_DIST:         52.69 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.55d {+17h 46m 11s}  -18.91d {-18d 54' 43"}
MOON_DIST:        86.02 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 03 Aug 17 17:52:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     766081,   Seg_Num: 0
POINT_RA:        174.934d {+11h 39m 44s} (J2000)
POINT_DEC:       -16.295d {-16d 17' 42"} (J2000)
ROLL:            308.000d
IMG_START_DATE:  17968 TJD;   215 DOY;   17/08/03
IMG_START_TIME:  63904.23 SOD {17:45:04.23} UT,   877.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     523475123
X_OFFSET:        648 [pixels]
Y_OFFSET:        935 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       808
Y_GRB_POS:       1095
BINNING_INDEX:   1
IM_URL:          sw00766081000msuni0897.fits
SUN_POSTN:       134.04d {+08h 56m 10s}  +17.31d {+17d 18' 29"}
SUN_DIST:         52.69 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      266.55d {+17h 46m 12s}  -18.91d {-18d 54' 44"}
MOON_DIST:        86.02 [deg]
MOON_ILLUM:      85 [%]
GAL_COORDS:      279.02, 43.22 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      182.03,-16.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #21406
P Veres and C Meegan (both UAH) report on behalf of the Fermi GBM Team:
"At 17:30:27.112 UT on 3 August 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170803A (trigger 523474232 / 170803729) which was also detected by the Swift/BAT (LaPorte et al., GCN 21405). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 40 degrees.
The GBM light curve consists of a single pulse with a duration (T90) of about 3.6 s (50-300 keV). The time-averaged spectrum from T0-0.1 s to T0+2.2 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.71 +/- 0.12 and the cutoff energy, parameterized as Epeak, is 154 +/- 13 keV.
The event fluence (10-1000 keV) in this time interval is (1.65 +/- 0.076)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.1 s in the 10-1000 keV band is 9.1 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #21407
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 2272 s of XRT Photon Counting mode data and 1 UVOT images for GRB 170803A, 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 = 174.93434, -16.31002 which is equivalent to:
```
RA (J2000): 11h 39m 44.24s
Dec (J2000): -16d 18' 36.1"
```
with an uncertainty of 1.7 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #21408
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), B. Mingo (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Cholden-Brown (PSU) and S.J. LaPorte report on behalf of the Swift-XRT team:
We have analysed 6.1 ks of XRT data for GRB 170803A (LaPorte et al. GCN Circ. 21405), from 68 s to 30.1 ks after the BAT trigger. The data comprise 312 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 21407).
The late-time light curve (from T0+5.6 ks) can be modelled with a power-law decay with a decay index of alpha=1.00 (+/-0.28).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.86 (+0.13, -0.12). The best-fitting absorption column is 1.3 (+/-0.4) x 10^21 cm^-2, in excess of the Galactic value of 3.5 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.3 (+/-0.4) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^20 cm^-2
Excess significance: 4.5 sigma
Photon index:	     1.86 (+0.13, -0.12)
```
If the light curve continues to decay with a power-law decay index of 1.00, the count rate at T+24 hours will be 6.3 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x 10^-13 (2.8 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00766081.
This circular is an official product of the Swift-XRT team.
GCN Circular #21411
S.W.K. Emery (UCL-MSSL) and S. J. LaPorte (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170803A 88 s after the BAT trigger (LaPorte et al., GCN Circ. 21405). GRB 170803A was also triggered by Fermi GBM (Veres and Meegan GCN Circ. 21406) A fading source consistent with the XRT position (Beardmore et al., GCN Circ. 21407) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
    RA  (J2000) =  11:39:44.11 = 174.93380 (deg.)
    Dec (J2000) = -16:18:38.0  = -16.31055 (deg.)
```
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white_FC            88          238          147         18.10 +/- 0.06
white              580         2241          322         19.69 +/- 0.12
u_FC               300          550          246         18.58 +/- 0.16
u                  775         2366          175         >19.34
b                  556         2386          191         20.02 +/- 0.35
uvw1              6216        23821          982         >20.74
uvm2             17025        17715          679         >20.57
uvw2              5602        30135          990         >21.05
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #21412
J. R. Cummings (CPI), S. D. Barthelmy (GSFC), H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+200 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170803A (trigger #766081) (LaPorte et al., GCN Circ. 21405). The BAT ground-calculated position is RA, Dec = 174.947, -16.312 deg which is
```
  RA(J2000)  =  11h 39m 47.2s
  Dec(J2000) = -16d 18' 41.9"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 94%.
The mask-weighted light curve shows a multi-peaked structure that starts at ~T-0.7 s and ends at ~T+4 s. The main peak occurs at ~T+0.1 s T90 (15-350 keV) is 3.82 +- 0.23 sec (estimated error including systematics).
The time-averaged spectrum from T-0.69 to T+4.14 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.65 +- 0.28, and Epeak of 100.2 +- 20.5 keV (chi squared 47.53 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 9.8 +- 0.4 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T-0.12 sec in the 15-150 keV band is 6.5 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.39 +- 0.06 (chi squared 71.10 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/766081/BA/
GCN Circular #21418
J. P. Norris (BSU), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), A. Y. Lien (GSFC/UMBC) report on behalf of the Swift-BAT team:
We report the spectral lag analysis for GRB 170803A (LaPorte et al., GCN Circ. 21405) based on the BAT data. The lag analysis finds a lag of 43 (+12, -12) ms for the 100-350 keV to 25-50 keV band, and 76 (+40, -26) ms for the 50-100 keV to 15-25 keV band. These values are consistent with those of long GRBs.

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Jochen Greiner, last update: 05-Aug-2017 [Disclaimer]