Gamma-ray Burst 170813A

(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:     Sun 13 Aug 17 01:14:32 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     767563,   Seg_Num: 0
GRB_RA:          201.054d {+13h 24m 13s} (J2000),
                 201.283d {+13h 25m 08s} (current),
                 200.404d {+13h 21m 37s} (1950)
GRB_DEC:          -5.469d {-05d 28' 07"} (J2000),
                  -5.560d {-05d 33' 36"} (current),
                  -5.209d {-05d 12' 30"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=2176 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        17978 TJD;   225 DOY;   17/08/13
GRB_TIME:        4396.48 SOD {01:13:16.48} UT
GRB_PHI:         -34.58 [deg]
GRB_THETA:        30.27 [deg]
SOLN_STATUS:     0x20000013
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    12.29 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  +2  +0  +0 -48  +0 
SUN_POSTN:       142.90d {+09h 31m 37s}  +14.65d {+14d 39' 13"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.52d {+01h 38m 04s}   +5.24d {+05d 14' 08"}
MOON_DIST:       176.76 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.81, 56.45 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      201.50,  3.14 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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 = 242.17,17.04 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(8.0<100sec) coincident with the FERMI_GBM event (trignum=524279593).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:13:32 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     524279593
GRB_RA:          208.900d {+13h 55m 36s} (J2000),
                 209.124d {+13h 56m 30s} (current),
                 208.266d {+13h 53m 04s} (1950)
GRB_DEC:          +2.617d {+02d 37' 00"} (J2000),
                  +2.531d {+02d 31' 51"} (current),
                  +2.861d {+02d 51' 40"} (1950)
GRB_ERROR:       21.87 [deg radius, statistical plus systematic]
GRB_INTEN:       93 [cnts/sec]
DATA_SIGNIF:     7.30 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        17978 TJD;   225 DOY;   17/08/13
GRB_TIME:        4388.80 SOD {01:13:08.80} UT
GRB_PHI:          60.00 [deg]
GRB_THETA:        30.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.48
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       1,1,1, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       142.90d {+09h 31m 36s}  +14.65d {+14d 39' 14"}
SUN_DIST:         66.37 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:       24.51d {+01h 38m 02s}   +5.23d {+05d 13' 57"}
MOON_DIST:       170.97 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      337.73, 61.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      205.91, 13.53 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170813051/quicklook/glg_lc_medres34_bn170813051.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 237.45,-22.62 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:13:42 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      57
TRIGGER_NUM:     524279593
GRB_RA:          211.933d {+14h 07m 44s} (J2000),
                 212.153d {+14h 08m 37s} (current),
                 211.310d {+14h 05m 14s} (1950)
GRB_DEC:          +6.650d {+06d 39' 00"} (J2000),
                  +6.567d {+06d 34' 01"} (current),
                  +6.887d {+06d 53' 13"} (1950)
GRB_ERROR:       10.52 [deg radius, statistical plus systematic]
GRB_INTEN:       117 [cnts/sec]
DATA_SIGNIF:     11.40 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        17978 TJD;   225 DOY;   17/08/13
GRB_TIME:        4388.80 SOD {01:13:08.80} UT
GRB_PHI:          60.00 [deg]
GRB_THETA:        25.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.42
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       1,1,1, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       142.90d {+09h 31m 36s}  +14.65d {+14d 39' 14"}
SUN_DIST:         68.32 [deg]   Sun_angle= -4.6 [hr] (East of Sun)
MOON_POSTN:       24.51d {+01h 38m 02s}   +5.23d {+05d 13' 59"}
MOON_DIST:       165.95 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      347.90, 62.66 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      207.35, 18.37 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170813051/quicklook/glg_lc_medres34_bn170813051.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 237.45,-22.62 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:13:46 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     524279593
GRB_RA:          206.020d {+13h 44m 05s} (J2000),
                 206.239d {+13h 44m 57s} (current),
                 205.400d {+13h 41m 36s} (1950)
GRB_DEC:          +9.310d {+09d 18' 36"} (J2000),
                  +9.222d {+09d 13' 19"} (current),
                  +9.561d {+09d 33' 39"} (1950)
GRB_ERROR:       7.85 [deg radius, statistical only]
DATA_SIGNIF:     13.30 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        17978 TJD;   225 DOY;   17/08/13
GRB_TIME:        4388.80 SOD {01:13:08.80} UT
GRB_PHI:          46.00 [deg]
GRB_THETA:        27.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       142.90d {+09h 31m 36s}  +14.65d {+14d 39' 14"}
SUN_DIST:         62.03 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:       24.51d {+01h 38m 02s}   +5.23d {+05d 13' 60"}
MOON_DIST:       165.44 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      340.30, 68.27 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      200.57, 18.70 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170813051/quicklook/glg_lc_medres34_bn170813051.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_524279593.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/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:15:56 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     767563,   Seg_Num: 0
GRB_RA:          201.0590d {+13h 24m 14.15s} (J2000),
                 201.2881d {+13h 25m 09.14s} (current),
                 200.4092d {+13h 21m 38.21s} (1950)
GRB_DEC:          -5.4918d {-05d 29' 30.4"} (J2000),
                  -5.5832d {-05d 34' 59.6"} (current),
                  -5.2314d {-05d 13' 53.1"} (1950)
GRB_ERROR:       6.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       5.59e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.09 [sigma]
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4530.58 SOD {01:15:30.58} UT,   134.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.22 261.53 243.46
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       142.90d {+09h 31m 37s}  +14.65d {+14d 39' 12"}
SUN_DIST:         61.31 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.53d {+01h 38m 07s}   +5.24d {+05d 14' 23"}
MOON_DIST:       176.75 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.81, 56.43 [deg] galactic lon,lat of the burst
ECL_COORDS:      201.52,  3.12 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.40 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:16:06 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     767563,   Seg_Num: 0
GRB_RA:          201.0590d {+13h 24m 14.1s} (J2000),
                 201.2881d {+13h 25m 09.1s} (current),
                 200.4092d {+13h 21m 38.2s} (1950)
GRB_DEC:          -5.4918d {-05d 29' 30.4"} (J2000),
                  -5.5832d {-05d 34' 59.6"} (current),
                  -5.2314d {-05d 13' 53.1"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       26 [cnts]
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4530.58 SOD {01:15:30.58} UT,   134.1 [sec] since BAT Trigger Time
CENTROID_X:      313.88,  raw= 314  [pixels]
CENTROID_Y:      321.20,  raw= 321  [pixels]
ROLL:            290.08 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   53.76
GRB_POS_XRT_Z:   17.64
IMAGE_URL:       sw00767563000msxps_rw.img
SUN_POSTN:       142.90d {+09h 31m 37s}  +14.65d {+14d 39' 12"}
SUN_DIST:         61.31 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.53d {+01h 38m 07s}   +5.24d {+05d 14' 25"}
MOON_DIST:       176.75 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.81, 56.43 [deg] galactic lon,lat of the burst
ECL_COORDS:      201.52,  3.12 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:16:08 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     767563,   Seg_Num: 0
GRB_RA:          201.0590d {+13h 24m 14.1s} (J2000),
                 201.2881d {+13h 25m 09.1s} (current),
                 200.4092d {+13h 21m 38.2s} (1950)
GRB_DEC:          -5.4918d {-05d 29' 30.4"} (J2000),
                  -5.5832d {-05d 34' 59.6"} (current),
                  -5.2314d {-05d 13' 53.1"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       26 [cnts]
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4530.58 SOD {01:15:30.58} UT,   134.1 [sec] since BAT Trigger Time
CENTROID_X:      313.88,  raw= 314  [pixels]
CENTROID_Y:      321.20,  raw= 321  [pixels]
ROLL:            290.08 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   53.76
GRB_POS_XRT_Z:   17.64
IMAGE_URL:       sw00767563000msxps_rw.img
SUN_POSTN:       142.90d {+09h 31m 37s}  +14.65d {+14d 39' 12"}
SUN_DIST:         61.31 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.53d {+01h 38m 08s}   +5.24d {+05d 14' 26"}
MOON_DIST:       176.75 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.81, 56.43 [deg] galactic lon,lat of the burst
ECL_COORDS:      201.52,  3.12 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:17:24 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     767563,   Seg_Num: 0
GRB_RA:          201.054d {+13h 24m 13s} (J2000),
                 201.283d {+13h 25m 08s} (current),
                 200.404d {+13h 21m 37s} (1950)
GRB_DEC:          -5.469d {-05d 28' 07"} (J2000),
                  -5.560d {-05d 33' 36"} (current),
                  -5.209d {-05d 12' 30"} (1950)
GRB_DATE:        17978 TJD;   225 DOY;   17/08/13
GRB_TIME:        4396.48 SOD {01:13:16.48} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -34.58 [deg]
GRB_THETA:        30.27 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    12.29 [sigma]
LC_URL:          sw00767563000msb.lc
SUN_POSTN:       142.90d {+09h 31m 37s}  +14.65d {+14d 39' 11"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.54d {+01h 38m 10s}   +5.24d {+05d 14' 39"}
MOON_DIST:       176.74 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.81, 56.45 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      201.50,  3.14 [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 an image 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 = 242.17,17.04 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:19:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.475d {-05d 28' 30"} (J2000)
POINT_ROLL:      290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4540.07 SOD {01:15:40.07} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.524
N_STARS:         26
X_OFFSET:        552 [pixels]
Y_OFFSET:        568 [pixels]
X_MAX:           1511 [pixels]
Y_MAX:           1527 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00767563000msufc0143.fits
SUN_POSTN:       142.91d {+09h 31m 37s}  +14.65d {+14d 39' 09"}
SUN_DIST:         61.30 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.56d {+01h 38m 15s}   +5.25d {+05d 15' 05"}
MOON_DIST:       176.72 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:20:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.475d {-05d 28' 30"} (J2000)
POINT_ROLL:      290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4540.07 SOD {01:15:40.07} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.524
N_STARS:         26
X_OFFSET:        552 [pixels]
Y_OFFSET:        568 [pixels]
X_MAX:           1511 [pixels]
Y_MAX:           1527 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00767563000msufc0143.fits
SUN_POSTN:       142.91d {+09h 31m 37s}  +14.65d {+14d 39' 09"}
SUN_DIST:         61.30 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.57d {+01h 38m 16s}   +5.25d {+05d 15' 09"}
MOON_DIST:       176.72 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [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:     Sun 13 Aug 17 01:21:16 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.475d {-05d 28' 30"} (J2000)
ROLL:            290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4540.07 SOD {01:15:40.07} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     524279759
X_OFFSET:        729 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw00767563000msuni0163.fits
SUN_POSTN:       142.91d {+09h 31m 38s}  +14.65d {+14d 39' 08"}
SUN_DIST:         61.30 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.58d {+01h 38m 19s}   +5.26d {+05d 15' 21"}
MOON_DIST:       176.71 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:21:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.475d {-05d 28' 30"} (J2000)
ROLL:            290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4540.07 SOD {01:15:40.07} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     524279759
X_OFFSET:        729 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw00767563000msuni0163.fits
SUN_POSTN:       142.91d {+09h 31m 38s}  +14.65d {+14d 39' 08"}
SUN_DIST:         61.30 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.58d {+01h 38m 19s}   +5.26d {+05d 15' 25"}
MOON_DIST:       176.71 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:26:43 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
POINT_ROLL:      290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4698.16 SOD {01:18:18.16} UT,   301.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.593
N_STARS:         13
X_OFFSET:        409 [pixels]
Y_OFFSET:        489 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1448 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00767563000msufc0301.fits
SUN_POSTN:       142.91d {+09h 31m 38s}  +14.65d {+14d 39' 04"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.63d {+01h 38m 30s}   +5.27d {+05d 16' 21"}
MOON_DIST:       176.66 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:27:00 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
POINT_ROLL:      290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4698.16 SOD {01:18:18.16} UT,   301.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.593
N_STARS:         13
X_OFFSET:        409 [pixels]
Y_OFFSET:        489 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1448 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00767563000msufc0301.fits
SUN_POSTN:       142.91d {+09h 31m 38s}  +14.65d {+14d 39' 04"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.63d {+01h 38m 31s}   +5.27d {+05d 16' 24"}
MOON_DIST:       176.66 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [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:     Sun 13 Aug 17 01:27:17 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     767563,   Seg_Num: 0
GRB_RA:          201.0571d {+13h 24m 13.70s} (J2000),
                 201.2862d {+13h 25m 08.69s} (current),
                 200.4073d {+13h 21m 37.75s} (1950)
GRB_DEC:          -5.4908d {-05d 29' 26.8"} (J2000),
                  -5.5822d {-05d 34' 56.0"} (current),
                  -5.2304d {-05d 13' 49.5"} (1950)
GRB_ERROR:       2.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4579.00 SOD {01:16:19.00} UT,   182.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       142.91d {+09h 31m 39s}  +14.65d {+14d 39' 04"}
SUN_DIST:         61.30 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.63d {+01h 38m 32s}   +5.27d {+05d 16' 27"}
MOON_DIST:       176.66 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.81, 56.43 [deg] galactic lon,lat of the burst
ECL_COORDS:      201.51,  3.12 [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:     Sun 13 Aug 17 01:28:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
ROLL:            290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4698.16 SOD {01:18:18.16} UT,   301.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     524279917
X_OFFSET:        729 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw00767563000msuni0321.fits
SUN_POSTN:       142.91d {+09h 31m 39s}  +14.65d {+14d 39' 03"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.64d {+01h 38m 33s}   +5.28d {+05d 16' 35"}
MOON_DIST:       176.65 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:28:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
ROLL:            290.083d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  4698.16 SOD {01:18:18.16} UT,   301.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     524279917
X_OFFSET:        729 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw00767563000msuni0321.fits
SUN_POSTN:       142.91d {+09h 31m 39s}  +14.65d {+14d 39' 03"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.64d {+01h 38m 34s}   +5.28d {+05d 16' 37"}
MOON_DIST:       176.65 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.14 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #21468
K. L. Page (U Leicester), J. A. Kennea (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Swift Team:
At 01:13:16 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170813A (trigger=767563). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 201.054, -5.469 which is
```
   RA(J2000) = 13h 24m 13s
   Dec(J2000) = -05d 28' 07"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 30 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~6 sec before the trigger.
The XRT began observing the field at 01:15:30.5 UT, 134.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 201.0572, -5.4909 which is equivalent to:
```
   RA(J2000)  = 13h 24m 13.73s
   Dec(J2000) = -05d 29' 27.1"
```
with an uncertainty of 2.8 arcseconds (radius, 90% containment). This location is 79 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 consistent with the Galactic value of 2.73 x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 5.59e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 143 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). 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:     Sun 13 Aug 17 01:34:25 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
POINT_ROLL:      290.084d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  5254.52 SOD {01:27:34.52} UT,   858.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.528
N_STARS:         59
X_OFFSET:        169 [pixels]
Y_OFFSET:        249 [pixels]
X_MAX:           1608 [pixels]
Y_MAX:           1688 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00767563000msufc0858.fits
SUN_POSTN:       142.92d {+09h 31m 40s}  +14.65d {+14d 38' 58"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.70d {+01h 38m 47s}   +5.30d {+05d 17' 44"}
MOON_DIST:       176.60 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.13 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 13 Aug 17 01:34:40 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
POINT_ROLL:      290.084d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  5254.52 SOD {01:27:34.52} UT,   858.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.528
N_STARS:         59
X_OFFSET:        169 [pixels]
Y_OFFSET:        249 [pixels]
X_MAX:           1608 [pixels]
Y_MAX:           1688 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw00767563000msufc0858.fits
SUN_POSTN:       142.92d {+09h 31m 40s}  +14.65d {+14d 38' 58"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.70d {+01h 38m 48s}   +5.30d {+05d 17' 47"}
MOON_DIST:       176.59 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.13 [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:     Sun 13 Aug 17 01:35:59 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
ROLL:            290.084d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  5254.52 SOD {01:27:34.52} UT,   858.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     524280474
X_OFFSET:        728 [pixels]
Y_OFFSET:        808 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       888
Y_GRB_POS:       968
BINNING_INDEX:   1
IM_URL:          sw00767563000msuni0878.fits
SUN_POSTN:       142.92d {+09h 31m 40s}  +14.65d {+14d 38' 57"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.71d {+01h 38m 50s}   +5.30d {+05d 18' 01"}
MOON_DIST:       176.58 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.13 [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:     Sun 13 Aug 17 01:36:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     767563,   Seg_Num: 0
POINT_RA:        201.060d {+13h 24m 14s} (J2000)
POINT_DEC:        -5.479d {-05d 28' 42"} (J2000)
ROLL:            290.084d
IMG_START_DATE:  17978 TJD;   225 DOY;   17/08/13
IMG_START_TIME:  5254.52 SOD {01:27:34.52} UT,   858.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     524280474
X_OFFSET:        728 [pixels]
Y_OFFSET:        808 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       888
Y_GRB_POS:       968
BINNING_INDEX:   1
IM_URL:          sw00767563000msuni0878.fits
SUN_POSTN:       142.92d {+09h 31m 40s}  +14.65d {+14d 38' 57"}
SUN_DIST:         61.29 [deg]   Sun_angle= -3.9 [hr] (East of Sun)
MOON_POSTN:       24.71d {+01h 38m 51s}   +5.30d {+05d 18' 03"}
MOON_DIST:       176.58 [deg]
MOON_ILLUM:      72 [%]
GAL_COORDS:      317.82, 56.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      201.51,  3.13 [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 #21469
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1507 s of XRT Photon Counting mode data and 3 UVOT images for GRB 170813A, 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 = 201.05759, -5.49079 which is equivalent to:
```
RA (J2000): 13h 24m 13.82s
Dec (J2000): -05d 29' 26.9"
```
with an uncertainty of 1.9 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 #21470
A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U. Leicester) and K. L. Page (U Leicester) report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 170813A (Page et al. GCN Circ. 21468), from 124 s to 39.0 ks after the BAT trigger. The data comprise 26 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 Osborne et al. (GCN Circ. 21469).
The light curve can be modelled with an initial power-law decay with an index of alpha=3.35 (+0.20, -0.18), followed by a break at T+796 s to an alpha of 0.9 (+0.5, -0.8).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.8 (+/-0.4). The best-fitting absorption column is 2.3 (+1.7, -1.3) x 10^21 cm^-2, in excess of the Galactic value of 2.7 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 4.0 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.3 (+1.7, -1.3) x 10^21 cm^-2
Galactic foreground: 2.7 x 10^20 cm^-2
Excess significance: 2.5 sigma
Photon index:	     1.8 (+/-0.4)
```
If the light curve continues to decay with a power-law decay index of 0.9, the count rate at T+24 hours will be 4.2 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-14 (2.2 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00767563.
This circular is an official product of the Swift-XRT team.
GCN Circular #21472
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Harvey Moseley (GSFC= ), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 170813A (Page, et al., GCN 21468) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional = on Sierra San Pedro M=E1rtir from 2017/08 13.15 to 2017/08 13.18 UTC (2.48 t= o 3.06 hours after the BAT trigger), obtaining a total of 0.36 hours exposu= re in the r and i bands and 0.15 hours exposure in the Z, Y, J, and H bands.
For a source within the Swift-XRT error circle (Osborne, et al., GCN 21469), in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma):
```
  r > 22.46
  i > 22.08
  Z > 20.23
  Y > 19.82
  J > 19.38
  H > 19.13
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #21473
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester), 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-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170813A (trigger #767563) (Page, et al., GCN Circ. 21468). The BAT ground-calculated position is RA, Dec = 201.057, -5.527 deg which is
```
 RA(J2000)  =  13h 24m 13.7s
 Dec(J2000) = -05d 31' 37.4"
```
with an uncertainty of 3.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 71%.
The mask-weighted light curve shows a initial ragged pulse with a fast rise starting at about T-10 sec, peaking at T+3 sec and then decaying to near background by T+40, followed by a second weaker pulse from T+40 to T+80 sec. T90 (15-350 keV) is 75.5 +- 10.9 sec (estimated error including systematics).
The time-averaged spectrum from T-9.2 to T+78.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.17 +- 0.14. The fluence in the 15-150 keV band is 1.9 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+2.64 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec. 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/767563/BA/

GCN Circular #21480
F. E. Marshall (NASA/GSFC) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170813A 144 s after the BAT trigger (Page et al., GCN Circ. 21468). No optical afterglow consistent with the enhanced XRT position (Osborne et al. GCN Circ. 21469) is detected in the initial UVOT exposures. 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           144          293          147         >20.1
u_FC               302          551          246         >19.8
white              144         6769          727         >21.4
v                  632        11867         1140         >19.3
b                  557         6564          432         >20.7
u                  302         6359          659         >20.4
w1                 682         6154          413         >19.9
m2                4314        12580         1090         >20.5
w2                5339        10954         1145         >20.4

GCN Circular #21491
S. Poolakkil (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 01:13:25 UT on 13 August 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170813A (trigger 524279593/ 170813051), which was also detected by the Swift/BAT (Page et al. 2017, GCN 21468). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 41 degrees.
The GBM light curve shows multiple pulses with a duration (T90) of about 112 s (50-300 keV). The time-averaged spectrum from T0-2.0 s to T0+23.6 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -0.52 +/- 0.11 and the cutoff energy, parameterized as Epeak, is 547 +/- 85 keV.
The event fluence (10-1000 keV) in this time interval is (8.09 +/- 0.51)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.7 s in the 10-1000 keV band is 2.36 +/- 0.17 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."

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Jochen Greiner, last update: 15-Aug-2017 [Disclaimer]