Gamma-ray Burst 180404B

(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 04 Apr 18 02:11:59 UT
NOTICE_TYPE:     Swift-BAT GRB Position 
TRIGGER_NUM:     821902,   Seg_Num: 0   
GRB_RA:           53.384d {+03h 33m 32s} (J2000),
                  53.520d {+03h 34m 05s} (current),
                  53.012d {+03h 32m 03s} (1950)
GRB_DEC:         -50.195d {-50d 11' 41"} (J2000),
                 -50.135d {-50d 08' 03"} (current),
                 -50.362d {-50d 21' 42"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5995 [cnts]    Image_Peak=464 [image_cnts]
TRIGGER_DUR:     1.024 [sec]    
TRIGGER_INDEX:   155     E_range: 50-350 keV
BKG_INTEN:       27355 [cnts]
BKG_TIME:        7891.27 SOD {02:11:31.27} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18212 TJD;    94 DOY;   18/04/04
GRB_TIME:        7904.07 SOD {02:11:44.07} UT
GRB_PHI:         -147.22 [deg]
GRB_THETA:        25.14 [deg]
SOLN_STATUS:     0x20010103  
RATE_SIGNIF:     39.33 [sigma]
IMAGE_SIGNIF:    14.59 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +3  +3  +0  +0 -41  +0
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 34"}
SUN_DIST:         65.75 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.45d {+15h 45m 48s}  -14.86d {-14d 51' 20"}
MOON_DIST:       114.96 [deg] 
MOON_ILLUM:      86 [%] 
GAL_COORDS:      260.92,-51.57 [deg] galactic lon,lat of the burst (or transient)      
ECL_COORDS:       23.48,-65.40 [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 position matches one of the nearby galaxy sources in the on-board catalog!
COMMENTS:        This does not match any source in the on-board catalog.
COMMENTS:        This matches a source in the ground catalog: 2M033312-502451, delta=0.225 [deg].
COMMENTS:        This is a GRB in nearby galaxy or it is noise.
COMMENTS:        This trigger occurred at longitude,latitude = 176.20,13.13 [deg].
COMMENTS:
COMMENTS:        NOTE: This BAT event is temporally(6.0<100sec) coincident with the FERMI_GBM event (trignum=544500703).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 04 Apr 18 02:12:05 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      48
TRIGGER_NUM:     544500703
GRB_RA:           72.367d {+04h 49m 28s} (J2000),
                  72.396d {+04h 49m 35s} (current),
                  72.288d {+04h 49m 09s} (1950)
GRB_DEC:         -64.667d {-64d 40' 00"} (J2000),
                 -64.636d {-64d 38' 08"} (current),
                 -64.751d {-64d 45' 03"} (1950)
GRB_ERROR:       16.08 [deg radius, statistical plus systematic]
GRB_INTEN:       167 [cnts/sec]
DATA_SIGNIF:     8.80 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        18212 TJD;    94 DOY;   18/04/04
GRB_TIME:        7898.64 SOD {02:11:38.64} UT
GRB_PHI:         288.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.17
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      98%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 1,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 34"}
SUN_DIST:         82.57 [deg]   Sun_angle= -4.0 [hr] (East of Sun)
MOON_POSTN:      236.45d {+15h 45m 48s}  -14.86d {-14d 51' 20"}
MOON_DIST:        99.58 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      275.34,-37.26 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        6.43,-82.51 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180404091/quicklook/glg_lc_medres34_bn180404091.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 160.17,-10.22 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(6.0<100sec) coincident with the SWIFT_BAT event (trignum=821902).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 04 Apr 18 02:12:18 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      71
TRIGGER_NUM:     544500703
GRB_RA:           60.517d {+04h 02m 04s} (J2000),
                  60.575d {+04h 02m 18s} (current),
                  60.359d {+04h 01m 26s} (1950)
GRB_DEC:         -63.317d {-63d 19' 00"} (J2000),
                 -63.267d {-63d 16' 00"} (current),
                 -63.454d {-63d 27' 14"} (1950)
GRB_ERROR:       5.07 [deg radius, statistical plus systematic]
GRB_INTEN:       522 [cnts/sec]
DATA_SIGNIF:     45.20 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18212 TJD;    94 DOY;   18/04/04
GRB_TIME:        7898.64 SOD {02:11:38.64} UT
GRB_PHI:         295.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.45
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       0,0,0, 1,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 34"}
SUN_DIST:         77.57 [deg]   Sun_angle= -3.2 [hr] (East of Sun)
MOON_POSTN:      236.45d {+15h 45m 49s}  -14.86d {-14d 51' 22"}
MOON_DIST:       101.81 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      276.14,-42.58 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        0.84,-77.23 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180404091/quicklook/glg_lc_medres34_bn180404091.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 160.17,-10.22 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(6.0<100sec) coincident with the SWIFT_BAT event (trignum=821902).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 04 Apr 18 02:12:13 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     544500703
GRB_RA:           60.517d {+04h 02m 04s} (J2000),
                  60.575d {+04h 02m 18s} (current),
                  60.359d {+04h 01m 26s} (1950)
GRB_DEC:         -63.317d {-63d 19' 00"} (J2000),
                 -63.267d {-63d 16' 00"} (current),
                 -63.454d {-63d 27' 14"} (1950)
GRB_ERROR:       5.63 [deg radius, statistical plus systematic]
GRB_INTEN:       375 [cnts/sec]
DATA_SIGNIF:     31.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18212 TJD;    94 DOY;   18/04/04
GRB_TIME:        7898.64 SOD {02:11:38.64} UT
GRB_PHI:         295.00 [deg]
GRB_THETA:        50.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      0.38
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,0,0, 1,1,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 34"}
SUN_DIST:         77.57 [deg]   Sun_angle= -3.2 [hr] (East of Sun)
MOON_POSTN:      236.45d {+15h 45m 49s}  -14.86d {-14d 51' 21"}
MOON_DIST:       101.81 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      276.14,-42.58 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        0.84,-77.23 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2018/bn180404091/quicklook/glg_lc_medres34_bn180404091.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 160.17,-10.22 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(6.0<100sec) coincident with the SWIFT_BAT event (trignum=821902).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 18 02:13:21 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     821902,   Seg_Num: 0
GRB_RA:           53.3967d {+03h 33m 35.20s} (J2000),
                  53.5326d {+03h 34m 07.83s} (current),
                  53.0247d {+03h 32m 05.93s} (1950)
GRB_DEC:         -50.2151d {-50d 12' 54.3"} (J2000),
                 -50.1546d {-50d 09' 16.5"} (current),
                 -50.3818d {-50d 22' 54.5"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.24e-08 [erg/cm2/sec]
GRB_SIGNIF:      15.09 [sigma]
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7973.96 SOD {02:12:53.96} UT,   69.9 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.22 261.58 243.49
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 35"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.46d {+15h 45m 51s}  -14.86d {-14d 51' 30"}
MOON_DIST:       114.94 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.95,-51.56 [deg] galactic lon,lat of the burst
ECL_COORDS:       23.47,-65.42 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This matches a source in the BAT ground catalog: 2M033312-502451,   delta=0.208 [deg].  
COMMENTS:        The XRT position is 1.30 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 04 Apr 18 02:13:37 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     821902,   Seg_Num: 0
GRB_RA:           53.3967d {+03h 33m 35.2s} (J2000),
                  53.5326d {+03h 34m 07.8s} (current),
                  53.0247d {+03h 32m 05.9s} (1950)
GRB_DEC:         -50.2151d {-50d 12' 54.3"} (J2000),
                 -50.1546d {-50d 09' 16.5"} (current),
                 -50.3818d {-50d 22' 54.5"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       228 [cnts]
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7973.96 SOD {02:12:53.96} UT,   69.9 [sec] since BAT Trigger Time
CENTROID_X:      311.92,  raw= 312  [pixels]
CENTROID_Y:      313.11,  raw= 313  [pixels]
ROLL:            315.12 [deg]
GAIN:            8
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   34.68
GRB_POS_XRT_Z:   13.01
IMAGE_URL:       sw00821902000msxps_rw.img
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 35"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.46d {+15h 45m 52s}  -14.86d {-14d 51' 32"}
MOON_DIST:       114.93 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.95,-51.56 [deg] galactic lon,lat of the burst
ECL_COORDS:       23.47,-65.42 [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 04 Apr 18 02:13:30 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     821902,   Seg_Num: 0
GRB_RA:           53.3967d {+03h 33m 35.2s} (J2000),
                  53.5326d {+03h 34m 07.8s} (current),
                  53.0247d {+03h 32m 05.9s} (1950)
GRB_DEC:         -50.2151d {-50d 12' 54.3"} (J2000),
                 -50.1546d {-50d 09' 16.5"} (current),
                 -50.3818d {-50d 22' 54.5"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       228 [cnts]
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7973.96 SOD {02:12:53.96} UT,   69.9 [sec] since BAT Trigger Time
CENTROID_X:      311.92,  raw= 312  [pixels]
CENTROID_Y:      313.11,  raw= 313  [pixels]
ROLL:            315.12 [deg]
GAIN:            8
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   34.68
GRB_POS_XRT_Z:   13.01
IMAGE_URL:       sw00821902000msxps_rw.img
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 35"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.46d {+15h 45m 51s}  -14.86d {-14d 51' 31"}
MOON_DIST:       114.94 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.95,-51.56 [deg] galactic lon,lat of the burst
ECL_COORDS:       23.47,-65.42 [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 04 Apr 18 02:13:37 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     821902,   Seg_Num: 0
GRB_RA:           53.3967d {+03h 33m 35.2s} (J2000),
                  53.5326d {+03h 34m 07.8s} (current),
                  53.0247d {+03h 32m 05.9s} (1950)
GRB_DEC:         -50.2151d {-50d 12' 54.3"} (J2000),
                 -50.1546d {-50d 09' 16.5"} (current),
                 -50.3818d {-50d 22' 54.5"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       228 [cnts]
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7973.96 SOD {02:12:53.96} UT,   69.9 [sec] since BAT Trigger Time
CENTROID_X:      311.92,  raw= 312  [pixels]
CENTROID_Y:      313.11,  raw= 313  [pixels]
ROLL:            315.12 [deg]
GAIN:            8
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   34.68
GRB_POS_XRT_Z:   13.01
IMAGE_URL:       sw00821902000msxps_rw.img
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 35"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.46d {+15h 45m 52s}  -14.86d {-14d 51' 32"}
MOON_DIST:       114.93 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.95,-51.56 [deg] galactic lon,lat of the burst
ECL_COORDS:       23.47,-65.42 [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 04 Apr 18 02:16:11 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.403d {+03h 33m 37s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 17"} (J2000)
POINT_ROLL:      315.122d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7985.56 SOD {02:13:05.56} UT,   81.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.961
N_STARS:         27
X_OFFSET:        420 [pixels]
Y_OFFSET:        490 [pixels]
X_MAX:           1379 [pixels]
Y_MAX:           1449 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    9
SL_URL:          sw00821902000msufc0081.fits
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 38"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.49d {+15h 45m 57s}  -14.86d {-14d 51' 52"}
MOON_DIST:       114.94 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.41 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 18 02:16:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.403d {+03h 33m 37s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 17"} (J2000)
POINT_ROLL:      315.122d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7985.56 SOD {02:13:05.56} UT,   81.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.961
N_STARS:         27
X_OFFSET:        420 [pixels]
Y_OFFSET:        490 [pixels]
X_MAX:           1379 [pixels]
Y_MAX:           1449 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    9
SL_URL:          sw00821902000msufc0081.fits
SUN_POSTN:        13.14d {+00h 52m 33s}   +5.63d {+05d 37' 38"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.49d {+15h 45m 57s}  -14.86d {-14d 51' 53"}
MOON_DIST:       114.94 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.41 [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 04 Apr 18 02:18:01 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.403d {+03h 33m 37s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 17"} (J2000)
ROLL:            315.122d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7985.56 SOD {02:13:05.56} UT,   81.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     544500806
X_OFFSET:        740 [pixels]
Y_OFFSET:        810 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       900
Y_GRB_POS:       970
BINNING_INDEX:   1
IM_URL:          sw00821902000msuni0102.fits
SUN_POSTN:        13.14d {+00h 52m 34s}   +5.63d {+05d 37' 40"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.50d {+15h 46m 01s}  -14.87d {-14d 52' 05"}
MOON_DIST:       114.93 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.41 [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 04 Apr 18 02:18:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.403d {+03h 33m 37s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 17"} (J2000)
ROLL:            315.122d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7985.56 SOD {02:13:05.56} UT,   81.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     544500806
X_OFFSET:        740 [pixels]
Y_OFFSET:        810 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       900
Y_GRB_POS:       970
BINNING_INDEX:   1
IM_URL:          sw00821902000msuni0102.fits
SUN_POSTN:        13.14d {+00h 52m 34s}   +5.63d {+05d 37' 40"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.50d {+15h 46m 01s}  -14.87d {-14d 52' 07"}
MOON_DIST:       114.93 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.41 [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 04 Apr 18 02:19:59 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     821902,   Seg_Num: 0
GRB_RA:           53.3926d {+03h 33m 34.22s} (J2000),
                  53.5285d {+03h 34m 06.85s} (current),
                  53.0206d {+03h 32m 04.94s} (1950)
GRB_DEC:         -50.2150d {-50d 12' 54.0"} (J2000),
                 -50.1545d {-50d 09' 16.1"} (current),
                 -50.3817d {-50d 22' 54.2"} (1950)
GRB_ERROR:       0.8 [arcsec radius, statistical only]
GRB_MAG:         18.61 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  7982.00 SOD {02:13:02.00} UT,   77.9 [sec] since BAT Trigger Time
SUN_POSTN:        13.14d {+00h 52m 34s}   +5.63d {+05d 37' 41"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.52d {+15h 46m 05s}  -14.87d {-14d 52' 20"}
MOON_DIST:       114.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.95,-51.56 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       23.46,-65.42 [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 9.4 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 18 02:23:58 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.407d {+03h 33m 38s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 18"} (J2000)
POINT_ROLL:      315.118d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  8198.64 SOD {02:16:38.64} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.134
N_STARS:         17
X_OFFSET:        420 [pixels]
Y_OFFSET:        490 [pixels]
X_MAX:           1379 [pixels]
Y_MAX:           1449 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00821902000msufc0294.fits
SUN_POSTN:        13.14d {+00h 52m 35s}   +5.63d {+05d 37' 45"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.56d {+15h 46m 13s}  -14.88d {-14d 52' 51"}
MOON_DIST:       114.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Apr 18 02:24:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.407d {+03h 33m 38s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 18"} (J2000)
POINT_ROLL:      315.118d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  8198.64 SOD {02:16:38.64} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.134
N_STARS:         17
X_OFFSET:        420 [pixels]
Y_OFFSET:        490 [pixels]
X_MAX:           1379 [pixels]
Y_MAX:           1449 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00821902000msufc0294.fits
SUN_POSTN:        13.14d {+00h 52m 35s}   +5.63d {+05d 37' 46"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.56d {+15h 46m 14s}  -14.88d {-14d 52' 53"}
MOON_DIST:       114.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.42 [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 04 Apr 18 02:25:25 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.407d {+03h 33m 38s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 18"} (J2000)
ROLL:            315.118d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  8198.64 SOD {02:16:38.64} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     544501019
X_OFFSET:        740 [pixels]
Y_OFFSET:        810 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       900
Y_GRB_POS:       970
BINNING_INDEX:   1
IM_URL:          sw00821902000msuni0315.fits
SUN_POSTN:        13.15d {+00h 52m 35s}   +5.63d {+05d 37' 47"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.57d {+15h 46m 16s}  -14.88d {-14d 53' 02"}
MOON_DIST:       114.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.42 [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 04 Apr 18 02:25:33 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     821902,   Seg_Num: 0
POINT_RA:         53.407d {+03h 33m 38s} (J2000)
POINT_DEC:       -50.205d {-50d 12' 18"} (J2000)
ROLL:            315.118d
IMG_START_DATE:  18212 TJD;    94 DOY;   18/04/04
IMG_START_TIME:  8198.64 SOD {02:16:38.64} UT,   294.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     544501019
X_OFFSET:        740 [pixels]
Y_OFFSET:        810 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       900
Y_GRB_POS:       970
BINNING_INDEX:   1
IM_URL:          sw00821902000msuni0315.fits
SUN_POSTN:        13.15d {+00h 52m 35s}   +5.63d {+05d 37' 47"}
SUN_DIST:         65.77 [deg]   Sun_angle= -2.7 [hr] (East of Sun)
MOON_POSTN:      236.57d {+15h 46m 17s}  -14.88d {-14d 53' 03"}
MOON_DIST:       114.92 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      260.93,-51.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       23.49,-65.42 [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 #22590
S. J. LaPorte (PSU), C. Gronwall (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 02:11:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180404B (trigger=821902). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 53.384, -50.195 which is
```
   RA(J2000) = 03h 33m 32s
   Dec(J2000) = -50d 11' 41"
```
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 50 sec. The peak count rate was ~9000 counts/sec (15-350 keV), at ~9 sec after the trigger.
The XRT began observing the field at 02:12:53.9 UT, 69.9 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 53.3967, -50.2151 which is equivalent to:
```
   RA(J2000)  = +03h 33m 35.21s
   Dec(J2000) = -50d 12' 54.4"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 78 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 81 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	03:33:34.24 =  53.39265
  DEC(J2000) = -50:12:54.1  = -50.21504
```
with a 90%-confidence error radius of about 0.76 arc sec. This position is 9.3 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.61 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is S. J. LaPorte (extragsam AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #22594
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 305 s of XRT Photon Counting mode data and 1 UVOT images for GRB 180404B, 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 = 53.39268, -50.21550 which is equivalent to:
```
RA (J2000): 03h 33m 34.24s
Dec (J2000): -50d 12' 55.8"
```
with an uncertainty of 2.9 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #22596
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, A.Kuznetsov, V.V.Chazov, A.V. Krylov, I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, P.Balanutsa Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA)
H.Levato, C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
D. Buckley South African Astronomical Observatory
O. Gres, N.M. Budnev, Yu.Ishmuhametova Irkutsk State University
A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk
MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Argentina was pointed to the GRB180404B (LaPorte et al. GCN 22590; Beardmore et al. GCN 22594) 27 sec after notice time and 45 sec after trigger time at 2018-04-04 02:12:29 UT. On our first 10s exposure image with unfiltered mlim=16.5 (5-sigma) we don't found optical transient within SWIFT error-box (ra=53.3792 dec=-50.195 r=0.05 LaPorte et al. GCN 22590)
MASTER auto-detection system detected OT with RA,Dec=53.392900; -50.214903 and unfiltered m_OT = 18.4 (automatic reduction) on the summary image with 670s exposition started on 2018-04-04 02:12:29 (mlim=19.7)
The message may be cited.
====================================================================
The observations started at zenit distance = 73 degrees, galaxy latitude b = -51 degree. The moon (86 % bright part) is 16 degrees above the horizon. The distance between moon and object is 115 The sun altitude was -46.8 degree.
GCN Circular #22597
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 02:11:38.64 UT on 04 April 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 180404B (trigger 544500703 / 180404091), which was also detected by the Swift/BAT (LaPorte et al. 2018, GCN 22590). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 61.3 degrees.
The GBM light curve shows a single bright peak followed by a secondary emission episode with a duration (T90) of about 80 s (50-300 keV). The time-averaged spectrum from T0+0.003 s to T0+33.281 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.40 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 209 +/- 6 keV.
The event fluence (10-1000 keV) in this time interval is (3.3 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+12.86 s in the 10-1000 keV band is 8.0 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak= 204 +/- 8 keV, alpha = -0.38 +/- 0.04 and beta = -3.3 +/- 0.6.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #22598
D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and S.J. LaPorte report on behalf of the Swift-XRT team:
We have analysed 8.4 ks of XRT data for GRB 180404B (LaPorte et al. GCN Circ. 22590), from 63 s to 30.6 ks after the BAT trigger. The data comprise 349 s in Windowed Timing (WT) mode (the first 5 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 22594).
The late-time light curve (from T0+5.2 ks) can be modelled with a power-law decay with a decay index of alpha=1.52 (+0.14, -0.13).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.61 (+/-0.04). The best-fitting absorption column is 3.00 (+0.25, -0.23) x 10^21 cm^-2, in excess of the Galactic value of 1.1 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.06 (+/-0.14) and a best-fitting absorption column of 4.2 (+/-0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.8 x 10^-11 (6.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     4.2 (+/-0.7) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^20 cm^-2
Excess significance: 10.0 sigma
Photon index:	     2.06 (+/-0.14)
```
If the light curve continues to decay with a power-law decay index of 1.52, the count rate at T+24 hours will be 4.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-13 (2.8 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/00821902.
This circular is an official product of the Swift-XRT team.
GCN Circular #22601
J. R. Cummings (CPI), S. D. Barthelmy (GSFC), H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180404B (trigger #821902) (LaPorte et al., GCN Circ. 22590). The BAT ground-calculated position is RA, Dec = 53.390, -50.213 deg which is
```
  RA(J2000)  =  03h 33m 33.6s
  Dec(J2000) = -50d 12' 47.4"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 84%.
The mask-weighted light curve shows a major pulse that starts at ~ T-6 s and peaks at ~ T+ 10 s. Another weaker pulse arises at the end of the major pulse at ~ T+40 s. The second pulse peaks at ~ T+50 s and lasts until ~ T+200 s. T90 (15-350 keV) is 111.5 +- 7.1 sec (estimated error including systematics).
The time-averaged spectrum from T-5.91 to T+195.64 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.35 +- 0.04. The fluence in the 15-150 keV band is 1.20 +- 0.02 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+8.88 sec in the 15-150 keV band is 5.2 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/821902/BA/
GCN Circular #22604
C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a large collaboration report:
We began observing Swift GRB180404B (LaPorte et al. GCN 22590) on April 4, 08:50 UT (mid time of 0.28 days post burst) with the LCO 2-m Faulkes Telescope South unit in Siding Springs in the SDSS-I filter. We do not detect the optical afterglow (LaPorte et al.; Lipunov et al. GCN 22596) down to the following limit:
```
Mid time since GRB=A0=A0=A0=A0 Exp=A0=A0=A0=A0=A0=A0=A0 Filter=A0=A0=A0=A0=
=A0=A0=A0=A0 Magnitude
(days)=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (s)
-------------------------------------------------------------
0.28=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 5x120=A0=A0=A0=
=A0=A0 SDSS-I=A0=A0=A0=A0=A0=A0=A0=A0 > 20.2
-------------------------------------------------------------
```
as calibrated against nearby USNO UCAC4 objects.
GCN Circular #22609
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 180404B (Swift-BAT detection: LaPorte et al., GCN Circ. 22590; Fermi-GBM observation: von Kienlin, GCN Circ. 22597) triggered Konus-Wind at T0=7898.049 s UT (02:11:38.049).
The burst light curve shows the bright pulse which starts at ~T0-3.4 s and has a total duration of ~29 s followed by a weaker pulse seen up to ~T0+100 s. The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180404_T07898/
As observed by Konus-Wind, the burst had a fluence of 2.60(-0.16,+0.18)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+8.832 s, of 2.07(-0.66,+0.66)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst (measured from T0 to T0+73.984 s) is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.65(-0.15,+0.16) and Ep = 205(-17,+21) keV (chi2 = 82/73 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.0 (chi2 = 82/72 dof).
The spectrum near the maximum count rate (measured from T0+8.448 to T0+16.640 s) is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model: with alpha = -0.19(-0.16,+0.17) and Ep = 186(-11,+12) keV (chi2 = 90/73 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.2 (chi2 = 90/72 dof).
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.

GCN Circular #22611
M. H. Siegel (PSU) and S. J. LaPorte (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180404B 82 s after the BAT trigger (LaPorte et al., GCN Circ. 22590). A fading source consistent with the XRT position (Beardmore et al. GCN Circ. 22594) is detected in the initial UVOT exposures.
The preliminary UVOT position is:

   RA  (J2000) =  03:33:34.23 =  53.39262 (deg.)
   Dec (J2000) = -50:12:54.2  = -50.21506 (deg.)

with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white (fc)          82          231          147         18.66 +/- 0.09
white               82         1720          411         19.39 +/- 0.09
white             6421         6620          196        >20.7
v                  624         7031          510        >19.5
b                  550         7661          322        >20.3
u (fc)             295          545          245         19.49 +/- 0.31
u                  295         1670          343         19.70 +/- 0.29
u                 6011         7648          393        >20.1
w1                 674         7442          510        >20.6
m2                1600         7236          413        >20.5
w2                 600         6826          452        >20.2

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).

GCN Circular #22645
V. Sharma (IUCAA), V. Bhalerao (IIT-B), D. Bhattacharya (IUCAA), 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 180404B, which was also detected by Swift (Palmer D. et al., GCN 22590), Fermi-GBM (Kienlin A. V. et al., GCN 22597) and Konus-Wind (Svinkin D. et al., GCN 22609).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 02:11:53.5 UT, ~9.5 s after the Swift trigger. The measured peak count rate is 281.6 cts/s above the background in combined data of four quadrants, with a total of 3662 cts. The local mean background count rate was 541 cts/s. Using cumulative rates, we measure a T90 of 44 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: 16-Apr-2018 [Disclaimer]