Gamma-ray Burst 180924A

(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:     Mon 24 Sep 18 15:23:01 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     863186,   Seg_Num: 0
GRB_RA:           49.161d {+03h 16m 39s} (J2000),
                  49.272d {+03h 17m 05s} (current),
                  48.865d {+03h 15m 28s} (1950)
GRB_DEC:         -58.505d {-58d 30' 19"} (J2000),
                 -58.437d {-58d 26' 14"} (current),
                 -58.688d {-58d 41' 16"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       11890 [cnts]    Image_Peak=305 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   289     E_range: 15-50 keV
BKG_INTEN:       105139 [cnts]
BKG_TIME:        55282.35 SOD {15:21:22.35} UT
BKG_DUR:         40 [sec]
GRB_DATE:        18385 TJD;   267 DOY;   18/09/24
GRB_TIME:        55342.38 SOD {15:22:22.38} UT
GRB_PHI:         145.70 [deg]
GRB_THETA:         8.21 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.48 [sigma]
IMAGE_SIGNIF:    7.17 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +1  -3  +0  +0 +34  +0 
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 33"}
SUN_DIST:        110.00 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      357.99d {+23h 51m 58s}   -5.13d {-05d 07' 54"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.32,-49.78 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        3.92,-69.97 [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 = 216.57,-12.29 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Sep 18 15:24:12 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     863186,   Seg_Num: 0
GRB_RA:           49.2001d {+03h 16m 48.02s} (J2000),
                  49.3112d {+03h 17m 14.68s} (current),
                  48.9044d {+03h 15m 37.05s} (1950)
GRB_DEC:         -58.5335d {-58d 32' 00.5"} (J2000),
                 -58.4654d {-58d 27' 55.5"} (current),
                 -58.7160d {-58d 42' 57.4"} (1950)
GRB_ERROR:       5.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.35e-09 [erg/cm2/sec]
GRB_SIGNIF:      7.21 [sigma]
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55419.15 SOD {15:23:39.15} UT,   76.8 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.20 261.66 243.34
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 34"}
SUN_DIST:        109.97 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.00d {+23h 52m 00s}   -5.13d {-05d 07' 41"}
MOON_DIST:        66.31 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.33,-49.74 [deg] galactic lon,lat of the burst
ECL_COORDS:        3.90,-70.01 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 2.08 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Sep 18 15:24:22 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     863186,   Seg_Num: 0
GRB_RA:           49.2001d {+03h 16m 48.0s} (J2000),
                  49.3112d {+03h 17m 14.6s} (current),
                  48.9044d {+03h 15m 37.0s} (1950)
GRB_DEC:         -58.5335d {-58d 32' 00.5"} (J2000),
                 -58.4654d {-58d 27' 55.5"} (current),
                 -58.7160d {-58d 42' 57.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       52 [cnts]
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55419.15 SOD {15:23:39.15} UT,   76.8 [sec] since BAT Trigger Time
CENTROID_X:      272.68,  raw= 273  [pixels]
CENTROID_Y:      281.53,  raw= 282  [pixels]
ROLL:            128.04 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -39.76
GRB_POS_XRT_Z:   -79.47
IMAGE_URL:       sw00863186000msxps_rw.img
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 35"}
SUN_DIST:        109.97 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.00d {+23h 52m 01s}   -5.13d {-05d 07' 39"}
MOON_DIST:        66.31 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.33,-49.74 [deg] galactic lon,lat of the burst
ECL_COORDS:        3.90,-70.01 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Sep 18 15:24:26 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     863186,   Seg_Num: 0
GRB_RA:           49.2001d {+03h 16m 48.0s} (J2000),
                  49.3112d {+03h 17m 14.6s} (current),
                  48.9044d {+03h 15m 37.0s} (1950)
GRB_DEC:         -58.5335d {-58d 32' 00.5"} (J2000),
                 -58.4654d {-58d 27' 55.5"} (current),
                 -58.7160d {-58d 42' 57.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       52 [cnts]
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55419.15 SOD {15:23:39.15} UT,   76.8 [sec] since BAT Trigger Time
CENTROID_X:      272.68,  raw= 273  [pixels]
CENTROID_Y:      281.53,  raw= 282  [pixels]
ROLL:            128.04 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -39.76
GRB_POS_XRT_Z:   -79.47
IMAGE_URL:       sw00863186000msxps_rw.img
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 35"}
SUN_DIST:        109.97 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.00d {+23h 52m 01s}   -5.13d {-05d 07' 38"}
MOON_DIST:        66.31 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.33,-49.74 [deg] galactic lon,lat of the burst
ECL_COORDS:        3.90,-70.01 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Sep 18 15:26:27 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     863186,   Seg_Num: 0
GRB_RA:           49.161d {+03h 16m 39s} (J2000),
                  49.272d {+03h 17m 05s} (current),
                  48.865d {+03h 15m 28s} (1950)
GRB_DEC:         -58.505d {-58d 30' 19"} (J2000),
                 -58.437d {-58d 26' 14"} (current),
                 -58.688d {-58d 41' 16"} (1950)
GRB_DATE:        18385 TJD;   267 DOY;   18/09/24
GRB_TIME:        55342.38 SOD {15:22:22.38} UT
TRIGGER_INDEX:   289
GRB_PHI:         145.70 [deg]
GRB_THETA:         8.21 [deg]
DELTA_TIME:      76.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.48 [sigma]
IMAGE_SIGNIF:    7.17 [sigma]
LC_URL:          sw00863186000msb.lc
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 37"}
SUN_DIST:        110.00 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.02d {+23h 52m 05s}   -5.12d {-05d 07' 17"}
MOON_DIST:        66.27 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.32,-49.78 [deg] galactic lon,lat of the burst (or transient
)
ECL_COORDS:        3.92,-69.97 [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 = 216.57,-12.29 [de
g].

GCN NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Mon 24 Sep 18 15:26:52 UT
NOTICE_TYPE:     Swift-UVOT Source List 
TRIGGER_NUM:     863186,   Seg_Num: 0 
POINT_RA:         49.180d {+03h 16m 43s} (J2000) 
POINT_DEC:       -58.511d {-58d 30' 39"} (J2000) 
POINT_ROLL:      128.047d 
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24 
IMG_START_TIME:  55425.16 SOD {15:23:45.16} UT,   82.8 [sec] since BAT Trigger Time 
FILTER:          10, White 
BKG_MEAN:        2.058 
N_STARS:         51 
X_OFFSET:        400 [pixels] 
Y_OFFSET:        592 [pixels] 
X_MAX:           1359 [pixels] 
Y_MAX:           1551 [pixels] 
DET_THRESH:      12 
PHOTO_THRESH:    6 
SL_URL:          sw00863186000msufc0082.fits 
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 37"} 
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun) 
MOON_POSTN:      358.02d {+23h 52m 06s}   -5.12d {-05d 07' 12"} 
MOON_DIST:        66.28 [deg] 
MOON_ILLUM:      100 [%] 
GAL_COORDS:      274.31,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.93,-69.99 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Sep 18 15:27:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     863186,   Seg_Num: 0
POINT_RA:         49.180d {+03h 16m 43s} (J2000)
POINT_DEC:       -58.511d {-58d 30' 39"} (J2000)
POINT_ROLL:      128.047d
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55425.16 SOD {15:23:45.16} UT,   82.8 [sec] since BAT Trigger T
ime
FILTER:          10, White
BKG_MEAN:        2.058
N_STARS:         51
X_OFFSET:        400 [pixels]
Y_OFFSET:        592 [pixels]
X_MAX:           1359 [pixels]
Y_MAX:           1551 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00863186000msufc0082.fits
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 37"}
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.02d {+23h 52m 06s}   -5.12d {-05d 07' 10"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.31,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.93,-69.99 [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:     Mon 24 Sep 18 15:28:12 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     863186,   Seg_Num: 0
POINT_RA:         49.180d {+03h 16m 43s} (J2000)
POINT_DEC:       -58.511d {-58d 30' 39"} (J2000)
ROLL:            128.047d
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55425.16 SOD {15:23:45.16} UT,   82.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     559495446
X_OFFSET:        961 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw00863186000msuni0104.fits
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 38"}
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.03d {+23h 52m 08s}   -5.12d {-05d 06' 58"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.31,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.93,-69.99 [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:     Mon 24 Sep 18 15:28:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     863186,   Seg_Num: 0
POINT_RA:         49.180d {+03h 16m 43s} (J2000)
POINT_DEC:       -58.511d {-58d 30' 39"} (J2000)
ROLL:            128.047d
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55425.16 SOD {15:23:45.16} UT,   82.8 [sec] since BAT Trigger T
ime
FILTER:          10, White
EXPOSURE_ID:     559495446
X_OFFSET:        961 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw00863186000msuni0104.fits
SUN_POSTN:       181.41d {+12h 05m 38s}   -0.61d {-00d 36' 39"}
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.04d {+23h 52m 08s}   -5.12d {-05d 06' 56"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.31,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.93,-69.99 [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:     Mon 24 Sep 18 15:34:34 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     863186,   Seg_Num: 0
POINT_RA:         49.178d {+03h 16m 43s} (J2000)
POINT_DEC:       -58.514d {-58d 30' 48"} (J2000)
POINT_ROLL:      128.046d
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55583.25 SOD {15:26:23.25} UT,   240.9 [sec] since BAT Trigger 
Time
FILTER:          7, U
BKG_MEAN:        1.327
N_STARS:         14
X_OFFSET:        641 [pixels]
Y_OFFSET:        537 [pixels]
X_MAX:           1600 [pixels]
Y_MAX:           1496 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00863186000msufc0240.fits
SUN_POSTN:       181.41d {+12h 05m 39s}   -0.61d {-00d 36' 45"}
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.09d {+23h 52m 21s}   -5.10d {-05d 05' 49"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.32,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.92,-69.99 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 24 Sep 18 15:35:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     863186,   Seg_Num: 0
POINT_RA:         49.178d {+03h 16m 43s} (J2000)
POINT_DEC:       -58.514d {-58d 30' 48"} (J2000)
POINT_ROLL:      128.046d
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55583.25 SOD {15:26:23.25} UT,   240.9 [sec] since BAT Trigger 
Time
FILTER:          7, U
BKG_MEAN:        1.327
N_STARS:         14
X_OFFSET:        641 [pixels]
Y_OFFSET:        537 [pixels]
X_MAX:           1600 [pixels]
Y_MAX:           1496 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00863186000msufc0240.fits
SUN_POSTN:       181.41d {+12h 05m 39s}   -0.61d {-00d 36' 45"}
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.09d {+23h 52m 22s}   -5.10d {-05d 05' 42"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.32,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.92,-69.99 [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:     Mon 24 Sep 18 15:35:46 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     863186,   Seg_Num: 0
POINT_RA:         49.178d {+03h 16m 43s} (J2000)
POINT_DEC:       -58.514d {-58d 30' 48"} (J2000)
ROLL:            128.046d
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55583.25 SOD {15:26:23.25} UT,   240.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     559495604
X_OFFSET:        961 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw00863186000msuni0262.fits
SUN_POSTN:       181.41d {+12h 05m 39s}   -0.61d {-00d 36' 46"}
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.10d {+23h 52m 23s}   -5.09d {-05d 05' 36"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.32,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.92,-69.99 [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:     Mon 24 Sep 18 15:35:55 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     863186,   Seg_Num: 0
POINT_RA:         49.178d {+03h 16m 43s} (J2000)
POINT_DEC:       -58.514d {-58d 30' 48"} (J2000)
ROLL:            128.046d
IMG_START_DATE:  18385 TJD;   267 DOY;   18/09/24
IMG_START_TIME:  55583.25 SOD {15:26:23.25} UT,   240.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     559495604
X_OFFSET:        961 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw00863186000msuni0262.fits
SUN_POSTN:       181.41d {+12h 05m 39s}   -0.61d {-00d 36' 46"}
SUN_DIST:        109.99 [deg]   Sun_angle= 8.8 [hr] (West of Sun)
MOON_POSTN:      358.10d {+23h 52m 23s}   -5.09d {-05d 05' 34"}
MOON_DIST:        66.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      274.32,-49.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        3.92,-69.99 [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 #23261
T. N. Ukwatta (LANL), A. P. Beardmore (U Leicester), A. A. Breeveld (UCL-MSSL), P. A. Evans (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), M. H. Siegel (PSU) and R. L. C. Starling (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team:
At 15:22:22 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180924A (trigger=863186). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 49.161, -58.505 which is
```
   RA(J2000) = 03h 16m 39s
   Dec(J2000) = -58d 30' 19"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 130 sec. The peak count rate was ~1492 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 15:23:39.1 UT, 76.8 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 49.2002, -58.5321 which is equivalent to:
```
   RA(J2000)  = 03h 16m 48.05s
   Dec(J2000) = -58d 31' 55.6"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 122 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 2.03 x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 1.35e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 82 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 0.03.
This source lies within the current (Sector 2) field-of-view of TESS camera 3.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta 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 Circular #23262
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1363 s of XRT Photon Counting mode data and 4 UVOT images for GRB 180924A, 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 = 49.19945, -58.53258 which is equivalent to:
```
RA (J2000): 03h 16m 47.87s
Dec (J2000): -58d 31' 57.3"
```
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 #23264
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+304 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180924A (trigger #863186) (Ukwata, et al., GCN Circ. 23261). The BAT ground-calculated position is RA, Dec = 49.207, -58.524 deg, which is
```
   RA(J2000)  =  03h 16m 49.7s 
   Dec(J2000) = -58d 31' 27.6" 
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shpws a couple peaks starting at ~T-90 sec, peaking at ~T=50 and ~T0 sec, and returning to baseline ~T+30 sec. T90 (15-350 keV) is 95.1 +- 10.9 sec (estimated error including systematics).
The time-averaged spectrum from T-85.15 to T+26.35 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.94 +- 0.14. The fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+2.73 sec in the 15-150 keV band is 0.6 +- 0.1 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/863186/BA/
GCN Circular #23266
A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and T.N. Ukwatta report on behalf of the Swift-XRT team:
We have analysed 6.4 ks of XRT data for GRB 180924A (Ukwatta et al. GCN Circ. 23261), from 82 s to 52.3 ks after the BAT trigger. The data comprise 141 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 23262).
The light curve can be modelled with an initial power-law decay with an index of alpha=2.23 (+0.11, -0.09), followed by a break at T+485 s to an alpha of 0.70 (+0.06, -0.05).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.96 (+0.14, -0.13). The best-fitting absorption column is 1.0 (+/-0.4) x 10^21 cm^-2, in excess of the Galactic value of 2.0 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.88 (+0.20, -0.19) and a best-fitting absorption column of 6.9 (+5.2, -4.5) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:        6.9 (+5.2, -4.5) x 10^20 cm^-2 
Galactic foreground: 2.0 x 10^20 cm^-2 
Excess significance: 1.8 sigma 
Photon index:        1.88 (+0.20, -0.19) 
```
If the light curve continues to decay with a power-law decay index of 0.70, the count rate at T+24 hours will be 0.017 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.8 x 10^-13 (6.6 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/00863186.
This circular is an official product of the Swift-XRT team.
GCN Circular #23267
V. Lipunov, E. Gorbovskoy, D. Vlasenko, N.Tiurina, V.Kornilov, A.Kuznetsov, V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, Lomonosov Moscow State University,SAI
A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
D. Buckley, South African Astronomical Observatory (SAAO)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias (IAC)
R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA)
H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University (ISU)
A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University (BSPU)
MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to Swift GRB 180924A (Ukwatta et al. GCN 23261, Evans et al. GCN 23262, Stamatikos et al. GCN 23264, Melandri et al. GCN 23266) 57128 sec after notice time and 57128 sec after trigger time at 2018-09-25 07:14:30 UT.
There is no new astrophysical sources detected brighter then 19.3m (unfiltered) inside Swift XRT error-box (03h 16m 47.87s -58d 31' 57.3", r=1.7arcsec Evans et al. GCN 23262)
The message may be cited.
====================================================================
The galacitc latitude b = -49.7 deg. The observations made on zenit distance = 27 deg. The moon (99.8 % bright part) was 40 deg. above the horizon. The distance between moon and object is 66 The sun altitude was -35.5 deg.
GCN Circular #23277
M. H. Siegel (PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180924A 83 s after the BAT trigger (Ukwatta et al., GCN Circ. 23261). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 23262) 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            83          233          147         >20.8
u_FC               241          491          246         >19.7
white               83          542          167         >20.9
v                  572          592           19         >17.1
b                  497          517           19         >18.4
u                  241          491          246         >19.7
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).

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Jochen Greiner, last update: 28-Sep-2018 [Disclaimer]