Gamma-ray Burst 210723A

(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:     Fri 23 Jul 21 14:46:30 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1061284,   Seg_Num: 0
GRB_RA:          121.726d {+08h 06m 54s} (J2000),
                 121.936d {+08h 07m 45s} (current),
                 121.239d {+08h 04m 57s} (1950)
GRB_DEC:         -32.889d {-32d 53' 20"} (J2000),
                 -32.953d {-32d 57' 08"} (current),
                 -32.744d {-32d 44' 37"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3612 [cnts]    Image_Peak=359 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       14955 [cnts]
BKG_TIME:        53156.57 SOD {14:45:56.57} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19418 TJD;   204 DOY;   21/07/23
GRB_TIME:        53170.91 SOD {14:46:10.91} UT
GRB_PHI:         -15.33 [deg]
GRB_THETA:        31.30 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     36.34 [sigma]
IMAGE_SIGNIF:    14.56 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +3  +0  +1 -60  +0 
SUN_POSTN:       123.19d {+08h 12m 46s}  +19.94d {+19d 56' 18"}
SUN_DIST:         52.90 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      296.94d {+19h 47m 45s}  -24.84d {-24d 50' 18"}
MOON_DIST:       122.01 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.31, -0.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      135.15,-51.47 [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 = 300.10,2.96 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:48:16 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
GRB_RA:          121.7202d {+08h 06m 52.8s} (J2000),
                 121.9304d {+08h 07m 43.2s} (current),
                 121.2328d {+08h 04m 55.8s} (1950)
GRB_DEC:         -32.8866d {-32d 53' 11.7"} (J2000),
                 -32.9499d {-32d 56' 59.6"} (current),
                 -32.7412d {-32d 44' 28.4"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       103 [cnts]
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53260.47 SOD {14:47:40.47} UT,   89.6 [sec] since BAT Trigger Time
CENTROID_X:      341.16,  raw= 341  [pixels]
CENTROID_Y:      313.90,  raw= 314  [pixels]
ROLL:            1.76 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   37.25
GRB_POS_XRT_Z:   79.60
IMAGE_URL:       sw01061284000msxps_rw.img
SUN_POSTN:       123.19d {+08h 12m 47s}  +19.94d {+19d 56' 17"}
SUN_DIST:         52.90 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      296.96d {+19h 47m 50s}  -24.84d {-24d 50' 11"}
MOON_DIST:       122.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.31, -0.34 [deg] galactic lon,lat of the burst
ECL_COORDS:      135.14,-51.47 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:48:19 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
GRB_RA:          121.7202d {+08h 06m 52.8s} (J2000),
                 121.9304d {+08h 07m 43.2s} (current),
                 121.2328d {+08h 04m 55.8s} (1950)
GRB_DEC:         -32.8866d {-32d 53' 11.7"} (J2000),
                 -32.9499d {-32d 56' 59.6"} (current),
                 -32.7412d {-32d 44' 28.4"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       103 [cnts]
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53260.47 SOD {14:47:40.47} UT,   89.6 [sec] since BAT Trigger Time
CENTROID_X:      341.16,  raw= 341  [pixels]
CENTROID_Y:      313.90,  raw= 314  [pixels]
ROLL:            1.76 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   37.25
GRB_POS_XRT_Z:   79.60
IMAGE_URL:       sw01061284000msxps_rw.img
SUN_POSTN:       123.19d {+08h 12m 47s}  +19.94d {+19d 56' 17"}
SUN_DIST:         52.90 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      296.96d {+19h 47m 50s}  -24.84d {-24d 50' 11"}
MOON_DIST:       122.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.31, -0.34 [deg] galactic lon,lat of the burst
ECL_COORDS:      135.14,-51.47 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:48:06 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1061284,   Seg_Num: 0
GRB_RA:          121.7202d {+08h 06m 52.84s} (J2000),
                 121.9304d {+08h 07m 43.29s} (current),
                 121.2328d {+08h 04m 55.86s} (1950)
GRB_DEC:         -32.8866d {-32d 53' 11.7"} (J2000),
                 -32.9499d {-32d 56' 59.6"} (current),
                 -32.7412d {-32d 44' 28.4"} (1950)
GRB_ERROR:       5.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       3.04e-09 [erg/cm2/sec]
GRB_SIGNIF:      10.14 [sigma]
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53260.47 SOD {14:47:40.47} UT,   89.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.69 237.16 261.77 243.47
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       123.19d {+08h 12m 46s}  +19.94d {+19d 56' 18"}
SUN_DIST:         52.90 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      296.95d {+19h 47m 49s}  -24.84d {-24d 50' 12"}
MOON_DIST:       122.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.31, -0.34 [deg] galactic lon,lat of the burst
ECL_COORDS:      135.14,-51.47 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.34 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:48:20 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      49
TRIGGER_NUM:     648744372
GRB_RA:          119.383d {+07h 57m 32s} (J2000),
                 119.568d {+07h 58m 16s} (current),
                 118.956d {+07h 55m 49s} (1950)
GRB_DEC:         -41.283d {-41d 16' 59"} (J2000),
                 -41.342d {-41d 20' 31"} (current),
                 -41.148d {-41d 08' 50"} (1950)
GRB_ERROR:       7.33 [deg radius, statistical plus systematic]
GRB_INTEN:       325 [cnts/sec]
DATA_SIGNIF:     11.90 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        19418 TJD;   204 DOY;   21/07/23
GRB_TIME:        53167.29 SOD {14:46:07.29} UT
GRB_PHI:         299.00 [deg]
GRB_THETA:        95.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.15
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 1,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       123.19d {+08h 12m 47s}  +19.94d {+19d 56' 17"}
SUN_DIST:         61.37 [deg]   Sun_angle= 0.2 [hr] (West of Sun)
MOON_POSTN:      296.96d {+19h 47m 50s}  -24.84d {-24d 50' 11"}
MOON_DIST:       113.78 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      256.47, -6.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      137.46,-59.97 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210723615/quicklook/glg_lc_medres34_bn210723615.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 229.87,15.17 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the CALET_GBM event (trignum=1311086521).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:52:32 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      61
TRIGGER_NUM:     648744372
GRB_RA:          120.700d {+08h 02m 48s} (J2000),
                 120.900d {+08h 03m 36s} (current),
                 120.236d {+08h 00m 57s} (1950)
GRB_DEC:         -36.367d {-36d 22' 00"} (J2000),
                 -36.428d {-36d 25' 40"} (current),
                 -36.226d {-36d 13' 31"} (1950)
GRB_ERROR:       6.40 [deg radius, statistical plus systematic]
GRB_INTEN:       330 [cnts/sec]
DATA_SIGNIF:     25.20 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        19418 TJD;   204 DOY;   21/07/23
GRB_TIME:        53167.29 SOD {14:46:07.29} UT
GRB_PHI:         304.00 [deg]
GRB_THETA:        95.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.32
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      93%  GRB
2nd_MOST_LIKELY:   3%  Distant Particles
DETECTORS:       0,0,0, 1,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       123.20d {+08h 12m 47s}  +19.94d {+19d 56' 15"}
SUN_DIST:         56.41 [deg]   Sun_angle= 0.2 [hr] (West of Sun)
MOON_POSTN:      297.00d {+19h 48m 01s}  -24.83d {-24d 49' 52"}
MOON_DIST:       118.63 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      252.80, -2.91 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      135.83,-55.03 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210723615/quicklook/glg_lc_medres34_bn210723615.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 229.87,15.17 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the CALET_GBM event (trignum=1311086521).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 23 Jul 21 17:39:45 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     648744372
GRB_RA:          118.890d {+07h 55m 34s} (J2000),
                 119.105d {+07h 56m 25s} (current),
                 118.390d {+07h 53m 34s} (1950)
GRB_DEC:         -30.040d {-30d 02' 23"} (J2000),
                 -30.098d {-30d 05' 52"} (current),
                 -29.906d {-29d 54' 22"} (1950)
GRB_ERROR:       2.96 [deg radius, statistical only]
GRB_DATE:        19418 TJD;   204 DOY;   21/07/23
GRB_TIME:        53167.29 SOD {14:46:07.29} UT
GRB_PHI:         310.07 [deg]
GRB_THETA:        92.83 [deg]
E_RANGE:         50.000 - 300.000 [keV]
LOC_ALGORITHM:   415 (Gnd S/W Version number)
SUN_POSTN:       123.31d {+08h 13m 15s}  +19.91d {+19d 54' 48"}
SUN_DIST:         50.18 [deg]   Sun_angle= 0.3 [hr] (West of Sun)
MOON_POSTN:      298.83d {+19h 55m 19s}  -24.62d {-24d 37' 05"}
MOON_DIST:       125.28 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      246.62, -0.89 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      130.12,-49.53 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210723615/quicklook/glg_lc_medres34_bn210723615.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210723615/quicklook/glg_locplot_all_bn210723615.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice has human-in-the-loop processing.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the CALET_GBM event (trignum=1311086521).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:49:54 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1061284,   Seg_Num: 0
GRB_RA:          121.726d {+08h 06m 54s} (J2000),
                 121.936d {+08h 07m 45s} (current),
                 121.239d {+08h 04m 57s} (1950)
GRB_DEC:         -32.889d {-32d 53' 20"} (J2000),
                 -32.953d {-32d 57' 08"} (current),
                 -32.744d {-32d 44' 37"} (1950)
GRB_DATE:        19418 TJD;   204 DOY;   21/07/23
GRB_TIME:        53170.91 SOD {14:46:10.91} UT
TRIGGER_INDEX:   146
GRB_PHI:         -15.33 [deg]
GRB_THETA:        31.30 [deg]
DELTA_TIME:      6.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     36.34 [sigma]
IMAGE_SIGNIF:    14.56 [sigma]
LC_URL:          sw01061284000msb.lc
SUN_POSTN:       123.19d {+08h 12m 47s}  +19.94d {+19d 56' 17"}
SUN_DIST:         52.90 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      296.97d {+19h 47m 54s}  -24.83d {-24d 50' 04"}
MOON_DIST:       122.02 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.31, -0.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      135.15,-51.47 [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 = 300.10,2.96 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:51:44 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.734d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.864d {-32d 51' 51"} (J2000)
POINT_ROLL:      1.756d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53270.06 SOD {14:47:50.06} UT,   99.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.508
N_STARS:         190
X_OFFSET:        305 [pixels]
Y_OFFSET:        608 [pixels]
X_MAX:           1264 [pixels]
Y_MAX:           1567 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw01061284000msufc0099.fits
SUN_POSTN:       123.20d {+08h 12m 47s}  +19.94d {+19d 56' 16"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      296.99d {+19h 47m 59s}  -24.83d {-24d 49' 56"}
MOON_DIST:       122.05 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.30, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 14:52:01 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.734d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.864d {-32d 51' 51"} (J2000)
POINT_ROLL:      1.756d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53270.06 SOD {14:47:50.06} UT,   99.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.508
N_STARS:         190
X_OFFSET:        305 [pixels]
Y_OFFSET:        608 [pixels]
X_MAX:           1264 [pixels]
Y_MAX:           1567 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw01061284000msufc0099.fits
SUN_POSTN:       123.20d {+08h 12m 47s}  +19.94d {+19d 56' 15"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.00d {+19h 47m 59s}  -24.83d {-24d 49' 55"}
MOON_DIST:       122.05 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.30, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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:     Fri 23 Jul 21 14:53:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.734d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.864d {-32d 51' 51"} (J2000)
ROLL:            1.756d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53270.06 SOD {14:47:50.06} UT,   99.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     648744497
X_OFFSET:        625 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       785
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw01061284000msuni0127.fits
SUN_POSTN:       123.20d {+08h 12m 47s}  +19.94d {+19d 56' 15"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.02d {+19h 48m 04s}  -24.83d {-24d 49' 47"}
MOON_DIST:       122.05 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.30, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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:     Fri 23 Jul 21 15:00:05 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
POINT_ROLL:      1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53482.89 SOD {14:51:22.89} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.782
N_STARS:         186
X_OFFSET:        305 [pixels]
Y_OFFSET:        575 [pixels]
X_MAX:           1264 [pixels]
Y_MAX:           1534 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01061284000msufc0311.fits
SUN_POSTN:       123.20d {+08h 12m 48s}  +19.94d {+19d 56' 11"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.09d {+19h 48m 21s}  -24.82d {-24d 49' 19"}
MOON_DIST:       122.06 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 15:00:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
POINT_ROLL:      1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53482.89 SOD {14:51:22.89} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.782
N_STARS:         186
X_OFFSET:        305 [pixels]
Y_OFFSET:        575 [pixels]
X_MAX:           1264 [pixels]
Y_MAX:           1534 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01061284000msufc0311.fits
SUN_POSTN:       123.20d {+08h 12m 48s}  +19.94d {+19d 56' 11"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.09d {+19h 48m 21s}  -24.82d {-24d 49' 18"}
MOON_DIST:       122.06 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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:     Fri 23 Jul 21 15:01:27 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
ROLL:            1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53482.89 SOD {14:51:22.89} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     648744710
X_OFFSET:        625 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       785
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw01061284000msuni0339.fits
SUN_POSTN:       123.20d {+08h 12m 49s}  +19.94d {+19d 56' 11"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.10d {+19h 48m 24s}  -24.82d {-24d 49' 13"}
MOON_DIST:       122.07 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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:     Fri 23 Jul 21 15:01:35 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
ROLL:            1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53482.89 SOD {14:51:22.89} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     648744710
X_OFFSET:        625 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       785
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw01061284000msuni0339.fits
SUN_POSTN:       123.20d {+08h 12m 49s}  +19.94d {+19d 56' 11"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.10d {+19h 48m 25s}  -24.82d {-24d 49' 13"}
MOON_DIST:       122.07 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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 #30485
T. Sbarrato (INAF-OAB), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), J. A. Kennea (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII), N. P. M. Kuin (UCL-MSSL), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
At 14:46:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210723A (trigger=1061284). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 121.726, -32.889 which is
```
   RA(J2000) = 08h 06m 54s
   Dec(J2000) = -32d 53' 20"
```
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 50 sec. The peak count rate was ~2200 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 14:47:40.4 UT, 89.6 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 121.72157, -32.88624 which is equivalent to:
```
   RA(J2000)  = 08h 06m 53.18s
   Dec(J2000) = -32d 53' 10.5"
```
with an uncertainty of 7.0 arcseconds (radius, 90% containment). This position may be improved as more data are received; the latest position is available at https://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 7.70 x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 3.04e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 99 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.
Although the data from this burst are consistent with a classical long GRB, we note that this source is close to the Galactic plane (lat = -0.34 degrees) which raises the possibility that this is a Galactic transient. If further analysis determines that to be the case, we would name the object Swift J0806.9-3253 .
Burst Advocate for this burst is T. Sbarrato (tullia.sbarrato AT inaf.it). 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/)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 15:08:08 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
POINT_ROLL:      1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  54038.17 SOD {15:00:38.17} UT,   867.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.876
N_STARS:         190
X_OFFSET:        65 [pixels]
Y_OFFSET:        335 [pixels]
X_MAX:           1504 [pixels]
Y_MAX:           1774 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw01061284000msufc0867.fits
SUN_POSTN:       123.21d {+08h 12m 50s}  +19.94d {+19d 56' 07"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.17d {+19h 48m 42s}  -24.81d {-24d 48' 44"}
MOON_DIST:       122.08 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 15:08:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
POINT_ROLL:      1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  54038.17 SOD {15:00:38.17} UT,   867.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.876
N_STARS:         190
X_OFFSET:        65 [pixels]
Y_OFFSET:        335 [pixels]
X_MAX:           1504 [pixels]
Y_MAX:           1774 [pixels]
DET_THRESH:      23
PHOTO_THRESH:    14
SL_URL:          sw01061284000msufc0867.fits
SUN_POSTN:       123.21d {+08h 12m 50s}  +19.94d {+19d 56' 07"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.18d {+19h 48m 42s}  -24.81d {-24d 48' 43"}
MOON_DIST:       122.08 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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:     Fri 23 Jul 21 15:08:32 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1061284,   Seg_Num: 0
GRB_RA:          121.7211d {+08h 06m 53.06s} (J2000),
                 121.9313d {+08h 07m 43.51s} (current),
                 121.2337d {+08h 04m 56.08s} (1950)
GRB_DEC:         -32.8853d {-32d 53' 07.0"} (J2000),
                 -32.9486d {-32d 56' 54.9"} (current),
                 -32.7399d {-32d 44' 23.7"} (1950)
GRB_ERROR:       1.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53536.00 SOD {14:52:16.00} UT,   365.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       123.21d {+08h 12m 50s}  +19.94d {+19d 56' 07"}
SUN_DIST:         52.90 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.18d {+19h 48m 43s}  -24.81d {-24d 48' 42"}
MOON_DIST:       122.06 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.31, -0.34 [deg] galactic lon,lat of the burst
ECL_COORDS:      135.14,-51.47 [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 0.11% < P(seren) < 0.58%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 23 Jul 21 15:10:02 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
ROLL:            1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  54038.17 SOD {15:00:38.17} UT,   867.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     648745265
X_OFFSET:        624 [pixels]
Y_OFFSET:        894 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       784
Y_GRB_POS:       1054
BINNING_INDEX:   1
IM_URL:          sw01061284000msuni0895.fits
SUN_POSTN:       123.21d {+08h 12m 50s}  +19.94d {+19d 56' 06"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.19d {+19h 48m 47s}  -24.81d {-24d 48' 36"}
MOON_DIST:       122.08 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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:     Fri 23 Jul 21 14:54:01 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.734d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.864d {-32d 51' 51"} (J2000)
ROLL:            1.756d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  53270.06 SOD {14:47:50.06} UT,   99.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     648744497
X_OFFSET:        625 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       785
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw01061284000msuni0127.fits
SUN_POSTN:       123.20d {+08h 12m 47s}  +19.94d {+19d 56' 14"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.02d {+19h 48m 05s}  -24.83d {-24d 49' 46"}
MOON_DIST:       122.05 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.30, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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:     Fri 23 Jul 21 15:10:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1061284,   Seg_Num: 0
POINT_RA:        121.732d {+08h 06m 56s} (J2000)
POINT_DEC:       -32.865d {-32d 51' 52"} (J2000)
ROLL:            1.759d
IMG_START_DATE:  19418 TJD;   204 DOY;   21/07/23
IMG_START_TIME:  54038.17 SOD {15:00:38.17} UT,   867.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     648745265
X_OFFSET:        624 [pixels]
Y_OFFSET:        894 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       784
Y_GRB_POS:       1054
BINNING_INDEX:   1
IM_URL:          sw01061284000msuni0895.fits
SUN_POSTN:       123.21d {+08h 12m 50s}  +19.94d {+19d 56' 06"}
SUN_DIST:         52.88 [deg]   Sun_angle= 0.1 [hr] (West of Sun)
MOON_POSTN:      297.20d {+19h 48m 47s}  -24.81d {-24d 48' 35"}
MOON_DIST:       122.09 [deg]
MOON_ILLUM:      100 [%]
GAL_COORDS:      250.29, -0.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      135.14,-51.45 [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 #30486
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 210723A, we find an enhanced XRT position of the afterglow: RA, Dec: 121.7213, -32.8851 which is equivalent to:
```
   RA (J2000)  = 08 06 53.12
   Dec (J2000) = -32 53 06.4
```
with an uncertainty of 1.9 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/1061284.
Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #30491
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
MASTER-OAFA robotic telescope (Global 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 the Swift GRB 210723A ( T. Sbarrato et al., GCN 30485) errorbox 29771 sec after notice time and 29801 sec after trigger time at 2021-07-23 23:02:52 UT, with upper limit up to 15.3 mag. Observations started at twilight. The observations began at zenith distance = 80 deg. The sun altitude is -14.6 deg.
The galactic latitude b = -0 deg., longitude l = 251 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1668344
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   29891 |         MASTER-OAFA |   C |   180 | 15.3 |        
   30091 |         MASTER-OAFA |   C |   180 | 14.7 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #30493
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), J.P. Osborne (U. Leicester) and T. Sbarrato report on behalf of the Swift-XRT team:
We have analysed 6.3 ks of XRT data for GRB 210723A (Sbarrato et al. GCN Circ. 30485), from 79 s to 57.3 ks after the BAT trigger. The data comprise 267 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. Using 3236 s of PC mode data and 6 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 121.72115, -32.88570 which is equivalent to:
```
RA (J2000): 08h 06m 53.08s
Dec(J2000): -32d 53' 08.5"
```
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=2.45 (+/-0.15). At T+154 s the decay flattens to an alpha of 1.67 (+/-0.09) before breaking again at T+959 s to a final decay with index alpha=1.04 (+0.09, -0.23).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.75 (+0.11, -0.10). The best-fitting absorption column is 1.26 (+0.14, -0.13) x 10^22 cm^-2, in excess of the Galactic value of 7.7 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.71 (+0.26, -0.25) and a best-fitting absorption column of 1.6 (+0.4, -0.3) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 6.5 x 10^-11 (1.1 x 10^-10) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.6 (+0.4, -0.3) x 10^22 cm^-2
Galactic foreground: 7.7 x 10^21 cm^-2
Excess significance: 4.1 sigma
Photon index:	     1.71 (+0.26, -0.25)
```
If the light curve continues to decay with a power-law decay index of 1.04, the count rate at T+24 hours will be 7.0 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.6 x 10^-13 (7.7 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/01061284.
This circular is an official product of the Swift-XRT team.
GCN Circular #30495
H. A. Krimm (NSF), S. D. Barthelmy (GSFC), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), T. Sbarrato (INAF-OAB), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+861 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210723A (trigger #1061284) (Sbarrato et al., GCN Circ. 30485). The BAT ground-calculated position is RA, Dec = 121.723, -32.893 deg which is
```
   RA(J2000)  =  08h 06m 53.4s
   Dec(J2000) = -32d 53' 35.8"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 77%.
The mask-weighted light curve shows a single-pulse structure that starts at ~T-5 s, peaks at ~T0, and ends at ~T+65 s. T90 (15-350 keV) is 48.54 +- 3.50 sec (estimated error including systematics).
The time-averaged spectrum from T-4.59 to T+66.64 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.85 +- 0.29, and Epeak of 88.2 +- 15.3 keV (chi squared 54.48 for 52 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.3 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+2.68 sec in the 15-150 keV band is 3.1 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.60 +- 0.06 (chi squared 75.55 for 53 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1061284/BA/
GCN Circular #30499
S. Lesage (UAH), B. Hristov (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
At 14:46:07 UT on 23 July 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210723A (trigger 648744372/210723615). which was also detected by Swift BAT (T. Sbarrato et al. 2021, GCN 30485) The Fermi GBM on-ground location is consistent with the Swift BAT position.
The angle from the Fermi LAT boresight is 94 degrees.
The GBM light curve consists of a single emission episode with a duration (T90) of about 43 s (10-1000 keV). The time-averaged spectrum from T0+1.5 to T0+36.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.67 +/- 0.07 and the cutoff energy, parameterized as Epeak, is 113 +/- 5 keV.
The event fluence (10-1000 keV) in this time interval is (7.6 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1 s in the 10-1000 keV band is 4.7 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular #30506
Y. Asaoka (ICRR), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
The long GRB 210723A (Swift detection: Sbarrato et al., GCN Circ. 30485, Krimm and Barthelmy, GCN Circ. 30495; Fermi GBM Observation: Lesage et al., GCN Circ. 30499; https://gcn.gsfc.nasa.gov/other/210723A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 14:46:05.572 UTC on 23 July 2021 (http://cgbm.calet.jp/cgbm_trigger/flight/1311086521/index.html). The burst signal was seen only by the SGM detector.
The burst light curve shows a single-pulse structure which starts at T+0.9 sec, peaks at T+12.6 sec,and ends at T+22.0 sec. The T90 and T50 durations measured by the SGM data are 17.2 +- 3.2 sec and 10.6 +- 3.2 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1311086521/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #30528
GRB 210723A: Swift/UVOT Upper Limits
S. J. LaPorte (PSU) and Sbarrato (INAF-OAB) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210723A 99 s after the BAT trigger (Sbarrato et al., GCN Circ. 30485). No optical afterglow consistent with the XRT position (Evans GCN Circ. 30486) 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            99          249          147         >20.6
u_FC               312          562          246         >19.2
white               99         1364          369         >20.6
v                  641         1241           78         >18.2
b                  567         1339           78         >19.3
u                  312         1315          304         >19.4
w1                 691         1290           58         >19.0
m2                 666         1266           78         >18.8
w2                 617         1217           78         >19.5
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.962 in the direction of the burst (Schlegel et al. 1998).

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Jochen Greiner, last update: 27-Jul-2021 [Disclaimer]