Gamma-ray Burst 180620B

(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:     Wed 20 Jun 18 15:50:55 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     843211,   Seg_Num: 0
GRB_RA:          357.517d {+23h 50m 04s} (J2000),
                 357.760d {+23h 51m 02s} (current),
                 356.854d {+23h 47m 25s} (1950)
GRB_DEC:         -57.957d {-57d 57' 25"} (J2000),
                 -57.854d {-57d 51' 15"} (current),
                 -58.235d {-58d 14' 06"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       7191 [cnts]    Image_Peak=870 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       26620 [cnts]
BKG_TIME:        57018.86 SOD {15:50:18.86} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18289 TJD;   171 DOY;   18/06/20
GRB_TIME:        57037.16 SOD {15:50:37.16} UT
GRB_PHI:         -176.70 [deg]
GRB_THETA:        30.39 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     59.04 [sigma]
IMAGE_SIGNIF:    16.36 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +4  +0  +0 +35  +0 
SUN_POSTN:        89.21d {+05h 56m 51s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.50d {+12h 14m 00s}   +3.11d {+03d 06' 32"}
MOON_DIST:       125.07 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      325.94,-50.22 [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 = 228.51,-18.51 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(1.0<100sec) coincident with the FERMI_GBM event (trignum=551202641).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:51:03 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      47
TRIGGER_NUM:     551202641
GRB_RA:          330.350d {+22h 01m 24s} (J2000),
                 330.678d {+22h 02m 43s} (current),
                 329.456d {+21h 57m 49s} (1950)
GRB_DEC:         -61.033d {-61d 01' 59"} (J2000),
                 -60.944d {-60d 56' 37"} (current),
                 -61.274d {-61d 16' 26"} (1950)
GRB_ERROR:       10.48 [deg radius, statistical plus systematic]
GRB_INTEN:       262 [cnts/sec]
DATA_SIGNIF:     9.30 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        18289 TJD;   171 DOY;   18/06/20
GRB_TIME:        57036.05 SOD {15:50:36.05} UT
GRB_PHI:         263.00 [deg]
GRB_THETA:       145.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.00
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:     100%  Below horizon
2nd_MOST_LIKELY:   0%  n/a
DETECTORS:       0,0,0, 0,1,0, 0,0,1, 0,0,0, 0,0,
SUN_POSTN:        89.21d {+05h 56m 51s}  +23.43d {+23d 26' 04"}
SUN_DIST:        124.09 [deg]   Sun_angle= 7.9 [hr] (West of Sun)
MOON_POSTN:      183.50d {+12h 14m 00s}   +3.11d {+03d 06' 30"}
MOON_DIST:       117.06 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      330.92,-45.78 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      306.55,-45.02 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180620660/quicklook/glg_lc_medres34_bn180620660.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 294.72,23.55 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=843211).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:51:13 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     551202641
GRB_RA:          330.383d {+22h 01m 32s} (J2000),
                 330.711d {+22h 02m 51s} (current),
                 329.491d {+21h 57m 58s} (1950)
GRB_DEC:         -60.933d {-60d 55' 59"} (J2000),
                 -60.844d {-60d 50' 37"} (current),
                 -61.174d {-61d 10' 26"} (1950)
GRB_ERROR:       8.50 [deg radius, statistical plus systematic]
GRB_INTEN:       328 [cnts/sec]
DATA_SIGNIF:     15.80 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18289 TJD;   171 DOY;   18/06/20
GRB_TIME:        57036.05 SOD {15:50:36.05} UT
GRB_PHI:         263.00 [deg]
GRB_THETA:       145.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.00
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:     100%  Below horizon
2nd_MOST_LIKELY:   0%  n/a
DETECTORS:       0,0,0, 0,1,0, 0,0,1, 0,0,0, 0,0,
SUN_POSTN:        89.21d {+05h 56m 51s}  +23.43d {+23d 26' 04"}
SUN_DIST:        124.10 [deg]   Sun_angle= 7.9 [hr] (West of Sun)
MOON_POSTN:      183.50d {+12h 14m 01s}   +3.11d {+03d 06' 28"}
MOON_DIST:       117.15 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      331.03,-45.85 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      306.64,-44.94 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180620660/quicklook/glg_lc_medres34_bn180620660.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 294.72,23.55 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=843211).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:52:36 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     843211,   Seg_Num: 0
GRB_RA:          357.5191d {+23h 50m 04.5s} (J2000),
                 357.7625d {+23h 51m 02.9s} (current),
                 356.8566d {+23h 47m 25.5s} (1950)
GRB_DEC:         -57.9639d {-57d 57' 50.0"} (J2000),
                 -57.8612d {-57d 51' 40.2"} (current),
                 -58.2420d {-58d 14' 31.0"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       195 [cnts]
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57120.36 SOD {15:52:00.36} UT,   83.2 [sec] since BAT Trigger Time
CENTROID_X:      309.92,  raw= 310  [pixels]
CENTROID_Y:      285.87,  raw= 286  [pixels]
ROLL:            78.39 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -29.51
GRB_POS_XRT_Z:   8.31
IMAGE_URL:       sw00843211000msxps_rw.img
SUN_POSTN:        89.21d {+05h 56m 51s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.52d {+12h 14m 04s}   +3.10d {+03d 06' 12"}
MOON_DIST:       125.05 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.00,-57.33 [deg] galactic lon,lat of the burst
ECL_COORDS:      325.94,-50.23 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:52:34 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     843211,   Seg_Num: 0
GRB_RA:          357.5191d {+23h 50m 04.5s} (J2000),
                 357.7625d {+23h 51m 02.9s} (current),
                 356.8566d {+23h 47m 25.5s} (1950)
GRB_DEC:         -57.9639d {-57d 57' 50.0"} (J2000),
                 -57.8612d {-57d 51' 40.2"} (current),
                 -58.2420d {-58d 14' 31.0"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       195 [cnts]
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57120.36 SOD {15:52:00.36} UT,   83.2 [sec] since BAT Trigger Time
CENTROID_X:      309.92,  raw= 310  [pixels]
CENTROID_Y:      285.87,  raw= 286  [pixels]
ROLL:            78.39 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -29.51
GRB_POS_XRT_Z:   8.31
IMAGE_URL:       sw00843211000msxps_rw.img
SUN_POSTN:        89.21d {+05h 56m 51s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.51d {+12h 14m 04s}   +3.10d {+03d 06' 13"}
MOON_DIST:       125.05 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.00,-57.33 [deg] galactic lon,lat of the burst
ECL_COORDS:      325.94,-50.23 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:52:24 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     843211,   Seg_Num: 0
GRB_RA:          357.5191d {+23h 50m 04.58s} (J2000),
                 357.7625d {+23h 51m 02.99s} (current),
                 356.8566d {+23h 47m 25.59s} (1950)
GRB_DEC:         -57.9639d {-57d 57' 50.0"} (J2000),
                 -57.8612d {-57d 51' 40.2"} (current),
                 -58.2420d {-58d 14' 31.0"} (1950)
GRB_ERROR:       4.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       7.04e-09 [erg/cm2/sec]
GRB_SIGNIF:      13.96 [sigma]
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57120.36 SOD {15:52:00.36} UT,   83.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.14 261.64 243.61
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        89.21d {+05h 56m 51s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.51d {+12h 14m 03s}   +3.10d {+03d 06' 15"}
MOON_DIST:       125.06 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.00,-57.33 [deg] galactic lon,lat of the burst
ECL_COORDS:      325.94,-50.23 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.41 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:54:53 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.521d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.955d {-57d 57' 16"} (J2000)
POINT_ROLL:      78.392d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57129.05 SOD {15:52:09.05} UT,   91.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.052
N_STARS:         25
X_OFFSET:        472 [pixels]
Y_OFFSET:        560 [pixels]
X_MAX:           1431 [pixels]
Y_MAX:           1519 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00843211000msufc0091.fits
SUN_POSTN:        89.22d {+05h 56m 52s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.54d {+12h 14m 08s}   +3.10d {+03d 05' 46"}
MOON_DIST:       125.06 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.22 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:55:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.521d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.955d {-57d 57' 16"} (J2000)
POINT_ROLL:      78.392d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57129.05 SOD {15:52:09.05} UT,   91.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.052
N_STARS:         25
X_OFFSET:        472 [pixels]
Y_OFFSET:        560 [pixels]
X_MAX:           1431 [pixels]
Y_MAX:           1519 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00843211000msufc0091.fits
SUN_POSTN:        89.22d {+05h 56m 52s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.54d {+12h 14m 09s}   +3.10d {+03d 05' 44"}
MOON_DIST:       125.05 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.22 [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:     Wed 20 Jun 18 15:56:16 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.521d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.955d {-57d 57' 16"} (J2000)
ROLL:            78.392d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57129.05 SOD {15:52:09.05} UT,   91.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     551202750
X_OFFSET:        811 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       971
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00843211000msuni0113.fits
SUN_POSTN:        89.22d {+05h 56m 52s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.55d {+12h 14m 11s}   +3.09d {+03d 05' 29"}
MOON_DIST:       125.05 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.22 [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:     Wed 20 Jun 18 15:56:24 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     843211,   Seg_Num: 0
GRB_RA:          357.517d {+23h 50m 04s} (J2000),
                 357.760d {+23h 51m 02s} (current),
                 356.854d {+23h 47m 25s} (1950)
GRB_DEC:         -57.957d {-57d 57' 25"} (J2000),
                 -57.854d {-57d 51' 15"} (current),
                 -58.235d {-58d 14' 06"} (1950)
GRB_DATE:        18289 TJD;   171 DOY;   18/06/20
GRB_TIME:        57037.16 SOD {15:50:37.16} UT
TRIGGER_INDEX:   146
GRB_PHI:         -176.70 [deg]
GRB_THETA:        30.39 [deg]
DELTA_TIME:      -70.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     59.04 [sigma]
IMAGE_SIGNIF:    16.36 [sigma]
LC_URL:          sw00843211000msb.lc
SUN_POSTN:        89.22d {+05h 56m 52s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.55d {+12h 14m 12s}   +3.09d {+03d 05' 28"}
MOON_DIST:       125.05 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      325.94,-50.22 [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 = 228.51,-18.51 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 15:56:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.521d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.955d {-57d 57' 16"} (J2000)
ROLL:            78.392d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57129.05 SOD {15:52:09.05} UT,   91.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     551202750
X_OFFSET:        811 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       971
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00843211000msuni0113.fits
SUN_POSTN:        89.22d {+05h 56m 52s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.55d {+12h 14m 12s}   +3.09d {+03d 05' 27"}
MOON_DIST:       125.05 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.22 [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:     Wed 20 Jun 18 15:57:01 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     843211,   Seg_Num: 0
GRB_RA:          357.5212d {+23h 50m 05.08s} (J2000),
                 357.7646d {+23h 51m 03.49s} (current),
                 356.8588d {+23h 47m 26.10s} (1950)
GRB_DEC:         -57.9622d {-57d 57' 43.9"} (J2000),
                 -57.8595d {-57d 51' 34.1"} (current),
                 -58.2403d {-58d 14' 24.9"} (1950)
GRB_ERROR:       0.8 [arcsec radius, statistical only]
GRB_MAG:         17.97 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57126.00 SOD {15:52:06.00} UT,   88.8 [sec] since BAT Trigger Time
SUN_POSTN:        89.22d {+05h 56m 52s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.43 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.55d {+12h 14m 13s}   +3.09d {+03d 05' 21"}
MOON_DIST:       125.04 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.00,-57.33 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      325.94,-50.23 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 7.2 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 16:00:08 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 04s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 27"} (J2000)
POINT_ROLL:      78.396d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57340.96 SOD {15:55:40.96} UT,   303.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.307
N_STARS:         16
X_OFFSET:        491 [pixels]
Y_OFFSET:        597 [pixels]
X_MAX:           1450 [pixels]
Y_MAX:           1556 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00843211000msufc0303.fits
SUN_POSTN:        89.22d {+05h 56m 53s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.58d {+12h 14m 19s}   +3.08d {+03d 04' 44"}
MOON_DIST:       125.03 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 16:00:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 04s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 27"} (J2000)
POINT_ROLL:      78.396d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57340.96 SOD {15:55:40.96} UT,   303.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.307
N_STARS:         16
X_OFFSET:        491 [pixels]
Y_OFFSET:        597 [pixels]
X_MAX:           1450 [pixels]
Y_MAX:           1556 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00843211000msufc0303.fits
SUN_POSTN:        89.22d {+05h 56m 53s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.58d {+12h 14m 20s}   +3.08d {+03d 04' 42"}
MOON_DIST:       125.03 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [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:     Wed 20 Jun 18 16:01:31 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 04s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 27"} (J2000)
ROLL:            78.396d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57340.96 SOD {15:55:40.96} UT,   303.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     551202962
X_OFFSET:        811 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       971
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00843211000msuni0325.fits
SUN_POSTN:        89.22d {+05h 56m 53s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.59d {+12h 14m 22s}   +3.07d {+03d 04' 28"}
MOON_DIST:       125.03 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [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:     Wed 20 Jun 18 16:01:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 04s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 27"} (J2000)
ROLL:            78.396d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57340.96 SOD {15:55:40.96} UT,   303.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     551202962
X_OFFSET:        811 [pixels]
Y_OFFSET:        917 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       971
Y_GRB_POS:       1077
BINNING_INDEX:   1
IM_URL:          sw00843211000msuni0325.fits
SUN_POSTN:        89.22d {+05h 56m 53s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.59d {+12h 14m 23s}   +3.07d {+03d 04' 27"}
MOON_DIST:       125.03 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [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:     Wed 20 Jun 18 16:08:57 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 26"} (J2000)
POINT_ROLL:      78.395d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57894.76 SOD {16:04:54.76} UT,   857.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        7.626
N_STARS:         71
X_OFFSET:        251 [pixels]
Y_OFFSET:        357 [pixels]
X_MAX:           1690 [pixels]
Y_MAX:           1796 [pixels]
DET_THRESH:      24
PHOTO_THRESH:    15
SL_URL:          sw00843211000msufc0857.fits
SUN_POSTN:        89.23d {+05h 56m 54s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.66d {+12h 14m 38s}   +3.05d {+03d 03' 02"}
MOON_DIST:       125.00 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 16:09:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 26"} (J2000)
POINT_ROLL:      78.395d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57894.76 SOD {16:04:54.76} UT,   857.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        7.626
N_STARS:         71
X_OFFSET:        251 [pixels]
Y_OFFSET:        357 [pixels]
X_MAX:           1690 [pixels]
Y_MAX:           1796 [pixels]
DET_THRESH:      24
PHOTO_THRESH:    15
SL_URL:          sw00843211000msufc0857.fits
SUN_POSTN:        89.23d {+05h 56m 54s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.66d {+12h 14m 39s}   +3.05d {+03d 02' 59"}
MOON_DIST:       125.00 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [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:     Wed 20 Jun 18 16:09:32 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     843211,   Seg_Num: 0
GRB_RA:          357.5212d {+23h 50m 05.08s} (J2000),
                 357.7646d {+23h 51m 03.49s} (current),
                 356.8588d {+23h 47m 26.10s} (1950)
GRB_DEC:         -57.9628d {-57d 57' 46.0"} (J2000),
                 -57.8601d {-57d 51' 36.2"} (current),
                 -58.2409d {-58d 14' 27.1"} (1950)
GRB_ERROR:       2.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57382.00 SOD {15:56:22.00} UT,   344.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        89.23d {+05h 56m 54s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.66d {+12h 14m 39s}   +3.05d {+03d 02' 55"}
MOON_DIST:       124.99 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.00,-57.33 [deg] galactic lon,lat of the burst
ECL_COORDS:      325.94,-50.23 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 20 Jun 18 16:10:38 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 26"} (J2000)
ROLL:            78.395d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57894.76 SOD {16:04:54.76} UT,   857.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     551203515
X_OFFSET:        810 [pixels]
Y_OFFSET:        916 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1076
BINNING_INDEX:   1
IM_URL:          sw00843211000msuni0879.fits
SUN_POSTN:        89.23d {+05h 56m 54s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.67d {+12h 14m 42s}   +3.04d {+03d 02' 42"}
MOON_DIST:       124.99 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [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:     Wed 20 Jun 18 16:10:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     843211,   Seg_Num: 0
POINT_RA:        357.519d {+23h 50m 05s} (J2000)
POINT_DEC:       -57.958d {-57d 57' 26"} (J2000)
ROLL:            78.395d
IMG_START_DATE:  18289 TJD;   171 DOY;   18/06/20
IMG_START_TIME:  57894.76 SOD {16:04:54.76} UT,   857.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     551203515
X_OFFSET:        810 [pixels]
Y_OFFSET:        916 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1076
BINNING_INDEX:   1
IM_URL:          sw00843211000msuni0879.fits
SUN_POSTN:        89.23d {+05h 56m 54s}  +23.43d {+23d 26' 04"}
SUN_DIST:        110.44 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:      183.68d {+12h 14m 42s}   +3.04d {+03d 02' 39"}
MOON_DIST:       124.99 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:      318.01,-57.34 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      325.95,-50.23 [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 #22807
P. A. Evans (U Leicester), A. A. Breeveld (UCL-MSSL), A. Deich (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 15:50:37 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180620B (trigger=843211). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 357.517, -57.957 which is
```
   RA(J2000) = 23h 50m 04s
   Dec(J2000) = -57d 57' 25"
```
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 30 sec. The peak count rate was ~9000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 15:52:00.3 UT, 83.2 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 357.52114, -57.96306 which is equivalent to:
```
   RA(J2000)  = 23h 50m 05.07s
   Dec(J2000) = -57d 57' 47.0"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 23 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 1.39 x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 7.04e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 91 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	23:50:05.10 = 357.52126
  DEC(J2000) = -57:57:44.1  = -57.96224
```
with a 90%-confidence error radius of about 0.75 arc sec. This position is 1.7 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.98 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #22813
B. Mailyan (UAH) reports on behalf of the Fermi GBM Team:
"At 15:50:36.05 UT on 20 June 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 180620B (trigger 551202641 / 180620660), which was also detected by the Swift/BAT and XRT (Evans et al. 2018, GCN 22807). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 137 degrees.
The GBM light curve shows multi-peaked structure with a duration (T90) of about 46.7 s (50-300 keV). Evans et al. 2018 report a shorter duration of ~30 s in the Swift/BAT. We suggest the discrepancy may be due to extended hard emission of this GRB.
The time-averaged spectrum from T0 to T0+46 s is adequately fit a power law function with an exponential high-energy cutoff. The power law index is 0.85 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 149 +/- 11 KeV. A Band function fits the spectrum equally well with Epeak= 106 +/- 15 keV, alpha = -0.5 +/- 0.2 and beta = -2.2 +/- 0.1.
The event fluence (10-1000 keV) in this time interval is (7.7 +/- 0.04)E-06 erg/cm^2. The 1-s peak photon flux measured starting from T0 in the 10-1000 keV band is 6.8 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #22814
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 3193 s of XRT Photon Counting mode data and 4 UVOT images for GRB 180620B, 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 = 357.52122, -57.96243 which is equivalent to:
```
RA (J2000): 23h 50m 5.09s
Dec (J2000): -57d 57' 44.8"
```
with an uncertainty of 1.4 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 #22817
A. Melandri (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/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 P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.6 ks of XRT data for GRB 180620B (Evans et al. GCN Circ. 22807), from 89 s to 56.0 ks after the BAT trigger. The data comprise 237 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 22814).
The late-time light curve (from T0+4.3 ks) can be modelled with a power-law decay with a decay index of alpha=0.61 (+/-0.08).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.34 (+/-0.05). The best-fitting absorption column is 2.30 (+/-0.15) x 10^21 cm^-2, in excess of the Galactic value of 1.4 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.99 (+0.11, -0.10) and a best-fitting absorption column of 1.6 (+/-0.3) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.6 (+/-0.3) x 10^21 cm^-2
Galactic foreground: 1.4 x 10^20 cm^-2
Excess significance: 7.9 sigma
Photon index:	     1.99 (+0.11, -0.10)
```
If the light curve continues to decay with a power-law decay index of 0.61, the count rate at T+24 hours will be 0.12 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.1 x 10^-12 (5.5 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00843211.
This circular is an official product of the Swift-XRT team.
GCN Circular #22819
Tassilo Schweyer and Patricia Schady (MPE Garching) report:
We observed the field of GRB 180620B (Swift trigger 843211; Evans et al., GCN #22807) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).
Observations started at 05:06 UT on 2018-06-21, 13.3 hours after the GRB trigger. They were performed at an average seeing of 1.6" and at an average airmass of 1.5.
We found a single, bright point source within the 1.4" Swift-XRT enhanced error circle reported by Beardmore et al. (GCN #22814) at
```
RA (J2000.0) = 23:50:05.088
Dec (J2000.0) = -57:57:43.88
```
with an uncertainty of 0.14" in each coordinate.
Based on a total exposure time of around 30mins we estimate the following AB magnitudes:
```
g' = 21.3 +/- 0.1 mag
r' = 20.8 +/- 0.1 mag
i' = 20.4 +/- 0.1 mag
z' = 20.3 +/- 0.1 mag
J = 19.7 +/- 0.1 mag
H = 19.6 +/- 0.2 mag
K = 19.1 +/- 0.4 mag
```
Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.01 in the direction of the burst (Schlafly & Finkbeiner 2011).
We thank Markus Rabus for the excellent support from La Silla.
GCN Circular #22821
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), P. A. Evans (U Leicester), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-179 to T+843 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180620B (trigger #843211) (Evans et al., GCN Circ. 22807). The BAT ground-calculated position is RA, Dec = 357.514, -57.954 deg which is
```
  RA(J2000)  =  23h 50m 03.3s
  Dec(J2000) = -57d 57' 13.5"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 78%.
The mask-weighted light curve shows a multi-peaked structure that starts at ~T-160 s and ends at ~T+160 s. The three main peaks occur at ~T0, ~T+40 s, and ~T+100 s, respectively. Note that because the event data are only available from ~T-180 s, there might be additional burst emission before the available event data range. T90 (15-350 keV) is 198.8 +- 27.4 sec (estimated error including systematics).
The time-averaged spectrum from T-159.376 to T+162.428 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.30 +- 0.20, and Epeak of 123.9 +- 68.3 keV (chi squared 58.09 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.0 +- 0.03 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T-0.33 sec in the 15-150 keV band is 3.6 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.60 +- 0.05 (chi squared 65.76 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/843211/BA/
GCN Circular #22823
L. Izzo (HETH/IAA-CSIC), M. Arabsalmani (CEA Saclay), D. B. Malesani (DAWN/NBI and DARK/NBI), K. Wiersema (Warwick), G. Pugliese (API/U. Amsterdam), S. D. Vergani (GEPI/Obs. Paris), A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), K. E. Heintz (Univ. Iceland and DAWN/NBI), D.A. Kann (HETH/IAA-CSIC), P. Schady (MPE), N.R. Tanvir (Leicester), J.P.U. Fynbo (DAWN/NBI), C. C. Thoene (HETH/IAA-CSIC), J. Bolmer (MPE Garching), report on behalf of the Stargate Consortium:
We observed the optical afterglow of GRB 180620B (Evans et al. GCN 22807; Schweyer & Schady GCN 22819) using the ESO Very Large Telescope (VLT) UT2 equipped with the X-shooter spectrograph. Spectroscopic observations started on 09:27 UT on 21 June 2018, i.e. 0.73 days after burst. In the resulting spectrum, we find a series of strong absorption lines that we identify as Fe II, Mg II, Mg I, Zn II, Cr II, Al II and Al III at a common redshift of 1.1175. At this redshift, we also detect emission lines of [O II], [Ne III] and Balmer lines. Both absorption and emission lines show velocity structure. The absorption profiles are broad and spread over more than 800 km/s in velocity space.
We are grateful to the visiting observers, Jean-Christophe Loison and Pedro Machado, for giving up some of their observing time. We thank the ESO staff, Marcela Espinoza and Alain Smette, for excellent support.
GCN Circular #22825
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 180620B (Swift-BAT detection: Evans et al., GCN Circ. 22807; Fermi-GBM detection: Mailyan, GCN Circ. 22813) triggered Konus-Wind at T0=57039.332 s UT (15:50:39.332).
The burst light curve shows a multi-peaked structure which starts at ~T0-156 s and has a total duration of ~260 s. The emission is seen up to 0.8 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180620_T57039/
As observed by Konus-Wind, the burst had a fluence of 1.19(-0.12,+0.14)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0-0.056 s, of 1.52(-0.61,+0.72)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The spectrum integrated over the most intense part of the burst (measured from T0 to T0+49.408 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.04(-0.31,+0.36) and Ep = 118(-16,+23) keV (chi2 = 44/57 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 44/56 dof).
The spectrum near the maximum count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: with alpha = -0.74(-0.33,+0.37) and Ep = 129(-15,+21) keV (chi2 = 66/57 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 66/56 dof).
Assuming the redshift z=1.1175 (Izzo et al., GCN Circ. 22823) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, and Omega_Lambda = 0.73, we estimate the following rest-frame parameters: the isotropic energy release E_iso is ~3.9x10^52 erg, the peak luminosity L_iso is ~1.0x10^52 erg/s, and the rest-frame peak energy of the time-integrated spectrum, Ep,i, is ~273 keV.
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #22827
A. A. Breeveld (UCL-MSSL), P. A. Evans (U. Leicester) and M. De Pasquale=20 (U. Instanbul) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180620B 92=20 s after the BAT trigger (Evans et al., GCN Circ. 22807). A source consistent with the enhanced XRT position (Beardmore et al.,=20 GCN Circ. 22814) and the Grond position (Schweyer and Schady, GCN Circ.=20 22819), and also detected by Izzo et al. (GCN Circ. 22823) is detected=20 in the initial UVOT exposures in all filters except uvw2. The=20 non-detection in the uvw2 filter is consistent with the redshift of 1.12=20 (Izzo et al. GCN Circ. 22823).
Preliminary detections and 3-sigma upper limits using the UVOT=20 photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for=20 the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               92          242          147         18.06 =B1 0.08
v                  634          826           39         17.41 =B1 0.22
b                  559          579           20         17.56 =B1 0.18
u                  304          554          246         17.40 =B1 0.09
uvw1              9950        18219         1394         20.17 =B1 0.2
uvm2              6563        16382          804         20.6 =B1 0.3
uvw2              4256         4443          183         > 19.7
```
The magnitudes in the table are not corrected for the Galactic=20 extinction due to the reddening of E(B-V) =3D 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #22844
V. Sharma, A. Vibhute and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:
Analysis of Astrosat CZTI data showed the detection of a long GRB 180620B, which was also detected by Swift (Evans P. A. et al., GCN 22807), Fermi-GBM (Mailyan B. et al., GCN 22813), Konus-Wind (Svinkin D. et al., GCN 22825).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 15:50:37.5 UT. The measured peak count rate is 259.6 cts/s above the background in combined data of four quadrants, with a total of 2643 cts. The local mean background count rate was 582.3 cts/s. Using cumulative rates, we measure a T90 of 22.3 s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.

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Jochen Greiner, last update: 25-Jun-2018 [Disclaimer]