Gamma-ray Burst 170912B

(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:     Tue 12 Sep 17 06:33:59 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     772052,   Seg_Num: 0
GRB_RA:          215.466d {+14h 21m 52s} (J2000),
                 215.801d {+14h 23m 12s} (current),
                 214.526d {+14h 18m 06s} (1950)
GRB_DEC:         -62.030d {-62d 01' 47"} (J2000),
                 -62.110d {-62d 06' 36"} (current),
                 -61.802d {-61d 48' 06"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       630 [cnts]    Image_Peak=93 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10409     E_range: 15-50 keV
BKG_INTEN:       28924 [cnts]
BKG_TIME:        23612.32 SOD {06:33:32.32} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18008 TJD;   255 DOY;   17/09/12
GRB_TIME:        23626.72 SOD {06:33:46.72} UT
GRB_PHI:         -152.89 [deg]
GRB_THETA:        10.37 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     20.73 [sigma]
IMAGE_SIGNIF:    9.99 [sigma]
MERIT_PARAMS:     +1  +0  +0  -4  +1  +0  +0  +1 -26  +0 
SUN_POSTN:       170.53d {+11h 22m 07s}   +4.08d {+04d 04' 45"}
SUN_DIST:         74.60 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.58d {+04h 22m 19s}  +16.35d {+16d 20' 56"}
MOON_DIST:       129.67 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      237.56,-44.59 [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 = 113.92,-13.96 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=526890831).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:34:11 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     526890831
GRB_RA:          211.383d {+14h 05m 32s} (J2000),
                 211.689d {+14h 06m 45s} (current),
                 210.525d {+14h 02m 06s} (1950)
GRB_DEC:         -56.817d {-56d 49' 00"} (J2000),
                 -56.901d {-56d 54' 01"} (current),
                 -56.578d {-56d 34' 40"} (1950)
GRB_ERROR:       8.62 [deg radius, statistical plus systematic]
GRB_INTEN:       207 [cnts/sec]
DATA_SIGNIF:     14.10 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        18008 TJD;   255 DOY;   17/09/12
GRB_TIME:        23626.91 SOD {06:33:46.91} UT
GRB_PHI:          88.00 [deg]
GRB_THETA:        35.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      2.32
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      75%  GRB
2nd_MOST_LIKELY:  22%  Generic SGR
DETECTORS:       1,0,0, 0,0,0, 0,0,0, 1,0,0, 0,0,
SUN_POSTN:       170.53d {+11h 22m 07s}   +4.08d {+04d 04' 45"}
SUN_DIST:         69.48 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:       65.58d {+04h 22m 19s}  +16.35d {+16d 20' 57"}
MOON_DIST:       132.13 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      312.98,  4.60 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      231.83,-40.88 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170912273/quicklook/glg_lc_medres34_bn170912273.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 147.32,24.70 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=772052).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:34:23 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     526890831
GRB_RA:          208.120d {+13h 52m 29s} (J2000),
                 208.434d {+13h 53m 44s} (current),
                 207.241d {+13h 48m 58s} (1950)
GRB_DEC:         -61.700d {-61d 42' 00"} (J2000),
                 -61.787d {-61d 47' 11"} (current),
                 -61.453d {-61d 27' 11"} (1950)
GRB_ERROR:       4.68 [deg radius, statistical only]
DATA_SIGNIF:     18.60 [sigma]
DATA_INTERVAL:   1.024 [sec]
GRB_DATE:        18008 TJD;   255 DOY;   17/09/12
GRB_TIME:        23626.91 SOD {06:33:46.91} UT
GRB_PHI:          90.00 [deg]
GRB_THETA:        40.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       170.53d {+11h 22m 07s}   +4.08d {+04d 04' 45"}
SUN_DIST:         71.98 [deg]   Sun_angle= -2.5 [hr] (East of Sun)
MOON_POSTN:       65.58d {+04h 22m 20s}  +16.35d {+16d 20' 59"}
MOON_DIST:       127.56 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      310.10,  0.32 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      233.02,-45.97 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2017/bn170912273/quicklook/glg_lc_medres34_bn170912273.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_526890831.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
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(0.0<100sec) coincident with the SWIFT_BAT event (trignum=772052).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:35:03 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     772052,   Seg_Num: 0
GRB_RA:          215.4638d {+14h 21m 51.31s} (J2000),
                 215.7987d {+14h 23m 11.67s} (current),
                 214.5245d {+14h 18m 05.87s} (1950)
GRB_DEC:         -61.9964d {-61d 59' 47.0"} (J2000),
                 -62.0765d {-62d 04' 35.3"} (current),
                 -61.7683d {-61d 46' 05.9"} (1950)
GRB_ERROR:       6.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       4.76e-10 [erg/cm2/sec]
GRB_SIGNIF:      4.69 [sigma]
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23676.98 SOD {06:34:36.98} UT,   50.3 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.19 261.64 243.46
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       170.53d {+11h 22m 07s}   +4.08d {+04d 04' 44"}
SUN_DIST:         74.58 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.59d {+04h 22m 21s}  +16.35d {+16d 21' 03"}
MOON_DIST:       129.70 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      313.33, -0.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      237.54,-44.56 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 2.02 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:35:13 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     772052,   Seg_Num: 0
GRB_RA:          215.4638d {+14h 21m 51.3s} (J2000),
                 215.7987d {+14h 23m 11.6s} (current),
                 214.5245d {+14h 18m 05.8s} (1950)
GRB_DEC:         -61.9964d {-61d 59' 47.0"} (J2000),
                 -62.0765d {-62d 04' 35.3"} (current),
                 -61.7683d {-61d 46' 05.9"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       22 [cnts]
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23676.98 SOD {06:34:36.98} UT,   50.3 [sec] since BAT Trigger Time
CENTROID_X:      257.75,  raw= 258  [pixels]
CENTROID_Y:      257.23,  raw= 257  [pixels]
ROLL:            312.97 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -97.04
GRB_POS_XRT_Z:   -114.67
IMAGE_URL:       sw00772052000msxps_rw.img
SUN_POSTN:       170.53d {+11h 22m 07s}   +4.08d {+04d 04' 44"}
SUN_DIST:         74.58 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.59d {+04h 22m 22s}  +16.35d {+16d 21' 04"}
MOON_DIST:       129.70 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      313.33, -0.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      237.54,-44.56 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:35:16 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     772052,   Seg_Num: 0
GRB_RA:          215.4638d {+14h 21m 51.3s} (J2000),
                 215.7987d {+14h 23m 11.6s} (current),
                 214.5245d {+14h 18m 05.8s} (1950)
GRB_DEC:         -61.9964d {-61d 59' 47.0"} (J2000),
                 -62.0765d {-62d 04' 35.3"} (current),
                 -61.7683d {-61d 46' 05.9"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       22 [cnts]
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23676.98 SOD {06:34:36.98} UT,   50.3 [sec] since BAT Trigger Time
CENTROID_X:      257.75,  raw= 258  [pixels]
CENTROID_Y:      257.23,  raw= 257  [pixels]
ROLL:            312.97 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -97.04
GRB_POS_XRT_Z:   -114.67
IMAGE_URL:       sw00772052000msxps_rw.img
SUN_POSTN:       170.53d {+11h 22m 07s}   +4.08d {+04d 04' 44"}
SUN_DIST:         74.58 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.59d {+04h 22m 22s}  +16.35d {+16d 21' 04"}
MOON_DIST:       129.70 [deg]
MOON_ILLUM:      62 [%]
GAL_COORDS:      313.33, -0.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      237.54,-44.56 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:37:29 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     772052,   Seg_Num: 0
GRB_RA:          215.466d {+14h 21m 52s} (J2000),
                 215.801d {+14h 23m 12s} (current),
                 214.526d {+14h 18m 06s} (1950)
GRB_DEC:         -62.030d {-62d 01' 47"} (J2000),
                 -62.110d {-62d 06' 36"} (current),
                 -61.802d {-61d 48' 06"} (1950)
GRB_DATE:        18008 TJD;   255 DOY;   17/09/12
GRB_TIME:        23626.83 SOD {06:33:46.83} UT
TRIGGER_INDEX:   10409
GRB_PHI:         -152.89 [deg]
GRB_THETA:        10.37 [deg]
DELTA_TIME:      -10.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     20.73 [sigma]
IMAGE_SIGNIF:    9.99 [sigma]
LC_URL:          sw00772052000msb.lc
SUN_POSTN:       170.53d {+11h 22m 08s}   +4.08d {+04d 04' 42"}
SUN_DIST:         74.60 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.61d {+04h 22m 27s}  +16.36d {+16d 21' 19"}
MOON_DIST:       129.67 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      237.56,-44.59 [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 = 113.92,-13.96 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:39:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.473d {+14h 21m 54s} (J2000)
POINT_DEC:       -62.038d {-62d 02' 15"} (J2000)
POINT_ROLL:      312.968d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23685.58 SOD {06:34:45.58} UT,   58.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.075
N_STARS:         190
X_OFFSET:        544 [pixels]
Y_OFFSET:        536 [pixels]
X_MAX:           1503 [pixels]
Y_MAX:           1495 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00772052000msufc0058.fits
SUN_POSTN:       170.53d {+11h 22m 08s}   +4.08d {+04d 04' 40"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.63d {+04h 22m 31s}  +16.36d {+16d 21' 30"}
MOON_DIST:       129.66 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:39:33 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.473d {+14h 21m 54s} (J2000)
POINT_DEC:       -62.038d {-62d 02' 15"} (J2000)
POINT_ROLL:      312.968d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23685.58 SOD {06:34:45.58} UT,   58.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.075
N_STARS:         190
X_OFFSET:        544 [pixels]
Y_OFFSET:        536 [pixels]
X_MAX:           1503 [pixels]
Y_MAX:           1495 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00772052000msufc0058.fits
SUN_POSTN:       170.53d {+11h 22m 08s}   +4.08d {+04d 04' 40"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.63d {+04h 22m 32s}  +16.36d {+16d 21' 32"}
MOON_DIST:       129.66 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:41:20 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.473d {+14h 21m 54s} (J2000)
POINT_DEC:       -62.038d {-62d 02' 15"} (J2000)
ROLL:            312.968d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23685.58 SOD {06:34:45.58} UT,   58.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     526890905
X_OFFSET:        1093 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1253
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00772052000msuni0078.fits
SUN_POSTN:       170.53d {+11h 22m 08s}   +4.08d {+04d 04' 38"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.65d {+04h 22m 36s}  +16.36d {+16d 21' 44"}
MOON_DIST:       129.66 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:41:35 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.473d {+14h 21m 54s} (J2000)
POINT_DEC:       -62.038d {-62d 02' 15"} (J2000)
ROLL:            312.968d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23685.58 SOD {06:34:45.58} UT,   58.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     526890905
X_OFFSET:        1093 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1253
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00772052000msuni0078.fits
SUN_POSTN:       170.53d {+11h 22m 08s}   +4.08d {+04d 04' 38"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.65d {+04h 22m 37s}  +16.36d {+16d 21' 45"}
MOON_DIST:       129.66 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:47:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
POINT_ROLL:      312.963d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23898.00 SOD {06:38:18.00} UT,   271.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.748
N_STARS:         143
X_OFFSET:        773 [pixels]
Y_OFFSET:        597 [pixels]
X_MAX:           1732 [pixels]
Y_MAX:           1556 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00772052000msufc0271.fits
SUN_POSTN:       170.54d {+11h 22m 09s}   +4.08d {+04d 04' 32"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.72d {+04h 22m 52s}  +16.37d {+16d 22' 26"}
MOON_DIST:       129.65 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.01 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN Circular #21864
S. J. LaPorte (PSU), J. A. Kennea (PSU), P. T. O'Brien (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team:
At 06:33:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170912B (trigger=772052). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 215.466, -62.030 which is
```
   RA(J2000) = 14h 21m 52s
   Dec(J2000) = -62d 01' 47"
```
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 20 sec. The peak count rate was ~9500 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 06:34:36.9 UT, 50.3 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 215.45921, -61.99674 which is equivalent to:
```
   RA(J2000)  = 14h 21m 50.21s
   Dec(J2000) = -61d 59' 48.3"
```
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 120 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 does not constrain the column density.
The initial flux in the 2.5 s image was 4.76e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 58 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. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the large, but uncertain extinction expected.
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:     Tue 12 Sep 17 06:48:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
POINT_ROLL:      312.963d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23898.00 SOD {06:38:18.00} UT,   271.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.748
N_STARS:         143
X_OFFSET:        773 [pixels]
Y_OFFSET:        597 [pixels]
X_MAX:           1732 [pixels]
Y_MAX:           1556 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00772052000msufc0271.fits
SUN_POSTN:       170.54d {+11h 22m 09s}   +4.08d {+04d 04' 32"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.72d {+04h 22m 53s}  +16.37d {+16d 22' 29"}
MOON_DIST:       129.65 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.01 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:49:20 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
ROLL:            312.963d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23898.00 SOD {06:38:18.00} UT,   271.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     526891117
X_OFFSET:        1093 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1253
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00772052000msuni0291.fits
SUN_POSTN:       170.54d {+11h 22m 09s}   +4.08d {+04d 04' 31"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.73d {+04h 22m 56s}  +16.38d {+16d 22' 36"}
MOON_DIST:       129.65 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.01 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:49:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
ROLL:            312.963d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23898.00 SOD {06:38:18.00} UT,   271.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     526891117
X_OFFSET:        1093 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1253
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00772052000msuni0291.fits
SUN_POSTN:       170.54d {+11h 22m 09s}   +4.08d {+04d 04' 30"}
SUN_DIST:         74.61 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.73d {+04h 22m 56s}  +16.38d {+16d 22' 37"}
MOON_DIST:       129.65 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.01 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:53:53 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
POINT_ROLL:      312.964d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  24503.17 SOD {06:48:23.17} UT,   876.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.860
N_STARS:         190
X_OFFSET:        533 [pixels]
Y_OFFSET:        357 [pixels]
X_MAX:           1972 [pixels]
Y_MAX:           1796 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    11
SL_URL:          sw00772052000msufc0876.fits
SUN_POSTN:       170.54d {+11h 22m 10s}   +4.07d {+04d 04' 26"}
SUN_DIST:         74.60 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.78d {+04h 23m 07s}  +16.38d {+16d 23' 05"}
MOON_DIST:       129.65 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 17 06:54:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
POINT_ROLL:      312.964d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  24503.17 SOD {06:48:23.17} UT,   876.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.860
N_STARS:         190
X_OFFSET:        533 [pixels]
Y_OFFSET:        357 [pixels]
X_MAX:           1972 [pixels]
Y_MAX:           1796 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    11
SL_URL:          sw00772052000msufc0876.fits
SUN_POSTN:       170.54d {+11h 22m 10s}   +4.07d {+04d 04' 26"}
SUN_DIST:         74.60 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.78d {+04h 23m 07s}  +16.39d {+16d 23' 07"}
MOON_DIST:       129.65 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:55:25 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
ROLL:            312.964d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  24503.17 SOD {06:48:23.17} UT,   876.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     526891722
X_OFFSET:        1092 [pixels]
Y_OFFSET:        916 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1252
Y_GRB_POS:       1076
BINNING_INDEX:   1
IM_URL:          sw00772052000msuni0896.fits
SUN_POSTN:       170.54d {+11h 22m 10s}   +4.07d {+04d 04' 25"}
SUN_DIST:         74.60 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.79d {+04h 23m 10s}  +16.39d {+16d 23' 15"}
MOON_DIST:       129.64 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 06:55:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     772052,   Seg_Num: 0
POINT_RA:        215.479d {+14h 21m 55s} (J2000)
POINT_DEC:       -62.037d {-62d 02' 14"} (J2000)
ROLL:            312.964d
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  24503.17 SOD {06:48:23.17} UT,   876.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     526891722
X_OFFSET:        1092 [pixels]
Y_OFFSET:        916 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1252
Y_GRB_POS:       1076
BINNING_INDEX:   1
IM_URL:          sw00772052000msuni0896.fits
SUN_POSTN:       170.54d {+11h 22m 10s}   +4.07d {+04d 04' 25"}
SUN_DIST:         74.60 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.79d {+04h 23m 11s}  +16.39d {+16d 23' 16"}
MOON_DIST:       129.64 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.32, -1.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      237.57,-44.60 [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:     Tue 12 Sep 17 07:08:37 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     772052,   Seg_Num: 0
GRB_RA:          215.4586d {+14h 21m 50.06s} (J2000),
                 215.7935d {+14h 23m 10.42s} (current),
                 214.5193d {+14h 18m 04.63s} (1950)
GRB_DEC:         -61.9968d {-61d 59' 48.4"} (J2000),
                 -62.0769d {-62d 04' 36.7"} (current),
                 -61.7687d {-61d 46' 07.3"} (1950)
GRB_ERROR:       3.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18008 TJD;   255 DOY;   17/09/12
IMG_START_TIME:  23715.00 SOD {06:35:15.00} UT,   88.3 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       170.55d {+11h 22m 12s}   +4.07d {+04d 04' 12"}
SUN_DIST:         74.56 [deg]   Sun_angle= -3.0 [hr] (East of Sun)
MOON_POSTN:       65.93d {+04h 23m 42s}  +16.41d {+16d 24' 41"}
MOON_DIST:       129.65 [deg]
MOON_ILLUM:      61 [%]
GAL_COORDS:      313.33, -0.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      237.53,-44.57 [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:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN Circular #21868
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1328 s of XRT Photon Counting mode data and 3 UVOT images for GRB 170912B, 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 = 215.45854, -61.99709 which is equivalent to:
```
RA (J2000): 14h 21m 50.05s
Dec (J2000): -61d 59' 49.5"
```
with an uncertainty of 1.8 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 #21872
P Veres (UAH), A von Kienlin (MPE) and C Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 06:33:46.91 UT on 12 September 2017, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170912B (trigger 526890831 / 170912273) which was also detected by the Swift satellite (LaPorte et al., GCN 21864). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 39 degrees.
The GBM light curve shows multiple overlapping peaks with a duration (T90) of about 13.3 s (50-300 keV). The time-averaged spectrum from T0-1.7 s to T0+13.7 s is best fit by a Band function with Epeak = 45.2 +/- 6.0 keV, alpha = -0.88 +/- 0.23, and beta = -2.13 +/- 0.06.
The event fluence (10-1000 keV) in this time interval is (4.5 +/- 0.2)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 8.7 +/- 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 #21873
S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and S.J. LaPorte report on behalf of the Swift-XRT team:
We have analysed 6.5 ks of XRT data for GRB 170912B (LaPorte et al. GCN Circ. 21864), from 45 s to 23.8 ks after the BAT trigger. The data comprise 15 s in Windowed Timing (WT) mode (the first 3 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. 21868).
The light curve can be modelled with an initial power-law decay with an index of alpha=0.69 (+/-0.09), followed by a break at T+3083 s to an alpha of 1.9 (+0.4, -0.3).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.7 (+/-0.3). The best-fitting absorption column is 4.1 (+0.9, -0.8) x 10^22 cm^-2, in excess of the Galactic value of 1.7 x 10^22 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 8.9 x 10^-11 (1.7 x 10^-10) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     4.1 (+0.9, -0.8) x 10^22 cm^-2
Galactic foreground: 1.7 x 10^22 cm^-2
Excess significance: 4.8 sigma
Photon index:	     1.7 (+/-0.3)
```
If the light curve continues to decay with a power-law decay index of 1.9, the count rate at T+24 hours will be 4.4 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.9 x 10^-14 (7.6 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/00772052.
This circular is an official product of the Swift-XRT team.
GCN Circular #21879
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), 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+480 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170912B (trigger #772052) (LaPorte et al., GCN Circ. 21864). The BAT ground-calculated position is RA, Dec = 215.464, -61.997 deg which is
```
  RA(J2000)  =  14h 21m 51.3s
  Dec(J2000) = -61d 59' 50.8"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shows several overlapping pulses that starts at ~ T0 and ends at ~ T+40 s. T90 (15-350 keV) is 19.6 +- 6.2 sec (estimated error including systematics).
The time-averaged spectrum from T-0.93 to T+38.75 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.88 +- 0.07. The fluence in the 15-150 keV band is 2.4 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.07 sec in the 15-150 keV band is 5.7 +- 0.3 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/772052/BA/

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Jochen Greiner, last update: 13-Sep-2017 [Disclaimer]