Gamma-ray Burst 200906A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:11:37 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     994856,   Seg_Num: 0
GRB_RA:          272.293d {+18h 09m 10s} (J2000),
                 272.275d {+18h 09m 06s} (current),
                 272.336d {+18h 09m 21s} (1950)
GRB_DEC:         +67.852d {+67d 51' 08"} (J2000),
                 +67.857d {+67d 51' 24"} (current),
                 +67.841d {+67d 50' 27"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       6889 [cnts]    Image_Peak=282 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   473     E_range: 25-100 keV
BKG_INTEN:       66904 [cnts]
BKG_TIME:        47430.41 SOD {13:10:30.41} UT
BKG_DUR:         24 [sec]
GRB_DATE:        19098 TJD;   250 DOY;   20/09/06
GRB_TIME:        47464.07 SOD {13:11:04.07} UT
GRB_PHI:         112.09 [deg]
GRB_THETA:         8.43 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.32 [sigma]
IMAGE_SIGNIF:    8.66 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +2  -1  +0  +0  +0  +0 
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 20"}
SUN_DIST:         90.47 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.47d {+02h 05m 53s}   +8.53d {+08d 31' 45"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       56.53, 88.43 [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 = 74.57,20.35 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:12:26 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     621090718
GRB_RA:          273.233d {+18h 12m 56s} (J2000),
                 273.000d {+18h 12m 00s} (current),
                 273.796d {+18h 15m 11s} (1950)
GRB_DEC:         +77.000d {+77d 00' 00"} (J2000),
                 +77.006d {+77d 00' 23"} (current),
                 +76.983d {+76d 58' 59"} (1950)
GRB_ERROR:       14.75 [deg radius, statistical plus systematic]
GRB_INTEN:       98 [cnts/sec]
DATA_SIGNIF:     8.70 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        19098 TJD;   250 DOY;   20/09/06
GRB_TIME:        47513.38 SOD {13:11:53.38} UT
GRB_PHI:          89.00 [deg]
GRB_THETA:        75.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      2.25
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      74%  GRB
2nd_MOST_LIKELY:  22%  Generic SGR
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 0,1,0, 0,0,
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 20"}
SUN_DIST:         87.85 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
MOON_POSTN:       31.48d {+02h 05m 54s}   +8.53d {+08d 31' 55"}
MOON_DIST:        87.79 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      108.31, 28.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       86.00, 79.52 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_lc_medres34_bn200906550.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 243.58,9.32 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(49.0<100sec) coincident with the SWIFT_BAT event (trignum=994856).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:12:19 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     621090718
GRB_RA:          256.550d {+17h 06m 12s} (J2000),
                 256.608d {+17h 06m 26s} (current),
                 256.411d {+17h 05m 39s} (1950)
GRB_DEC:         +61.600d {+61d 36' 00"} (J2000),
                 +61.573d {+61d 34' 24"} (current),
                 +61.665d {+61d 39' 54"} (1950)
GRB_ERROR:       24.62 [deg radius, statistical plus systematic]
GRB_INTEN:       74 [cnts/sec]
DATA_SIGNIF:     4.70 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        19098 TJD;   250 DOY;   20/09/06
GRB_TIME:        47513.38 SOD {13:11:53.38} UT
GRB_PHI:          85.00 [deg]
GRB_THETA:        90.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      2.71
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      61%  GRB
2nd_MOST_LIKELY:  25%  Generic SGR
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 0,1,0, 0,0,
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 20"}
SUN_DIST:         85.07 [deg]   Sun_angle= -6.1 [hr] (East of Sun)
MOON_POSTN:       31.48d {+02h 05m 54s}   +8.53d {+08d 31' 53"}
MOON_DIST:       101.63 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       91.10, 36.07 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      213.96, 82.34 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_lc_medres34_bn200906550.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 243.58,9.32 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(49.0<100sec) coincident with the SWIFT_BAT event (trignum=994856).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:12:40 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     621090718
GRB_RA:          270.510d {+18h 02m 02s} (J2000),
                 270.371d {+18h 01m 29s} (current),
                 270.845d {+18h 03m 23s} (1950)
GRB_DEC:         +74.080d {+74d 04' 48"} (J2000),
                 +74.081d {+74d 04' 51"} (current),
                 +74.077d {+74d 04' 36"} (1950)
GRB_ERROR:       5.70 [deg radius, statistical only]
DATA_SIGNIF:     9.00 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        19098 TJD;   250 DOY;   20/09/06
GRB_TIME:        47513.38 SOD {13:11:53.38} UT
GRB_PHI:          89.00 [deg]
GRB_THETA:        78.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 19"}
SUN_DIST:         88.08 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       31.48d {+02h 05m 55s}   +8.53d {+08d 31' 57"}
MOON_DIST:        89.85 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      105.02, 29.39 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       88.93, 82.48 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_lc_medres34_bn200906550.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_621090718.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(49.0<100sec) coincident with the SWIFT_BAT event (trignum=994856).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:13:19 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      0
TRIGGER_NUM:     621090718
GRB_RA:          266.610d {+17h 46m 26s} (J2000),
                 266.606d {+17h 46m 25s} (current),
                 266.620d {+17h 46m 29s} (1950)
GRB_DEC:         +66.850d {+66d 50' 60"} (J2000),
                 +66.843d {+66d 50' 35"} (current),
                 +66.866d {+66d 51' 59"} (1950)
GRB_ERROR:       4.72 [deg radius, statistical only]
DATA_SIGNIF:     11.10 [sigma]
DATA_INTERVAL:   10.240 [sec]
GRB_DATE:        19098 TJD;   250 DOY;   20/09/06
GRB_TIME:        47513.38 SOD {13:11:53.38} UT
GRB_PHI:          89.00 [deg]
GRB_THETA:        85.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 19"}
SUN_DIST:         88.63 [deg]   Sun_angle= -6.7 [hr] (East of Sun)
MOON_POSTN:       31.48d {+02h 05m 56s}   +8.53d {+08d 32' 05"}
MOON_DIST:        94.93 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       96.76, 31.14 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      166.27, 88.63 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_lc_medres34_bn200906550.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_621090718.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(49.0<100sec) coincident with the SWIFT_BAT event (trignum=994856).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:21:15 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     621090718
GRB_RA:          270.000d {+18h 00m 00s} (J2000),
                 269.972d {+17h 59m 53s} (current),
                 270.068d {+18h 00m 16s} (1950)
GRB_DEC:         +68.560d {+68d 33' 36"} (J2000),
                 +68.560d {+68d 33' 36"} (current),
                 +68.560d {+68d 33' 35"} (1950)
GRB_ERROR:       4.08 [deg radius, statistical only]
GRB_DATE:        19098 TJD;   250 DOY;   20/09/06
GRB_TIME:        47513.38 SOD {13:11:53.38} UT
GRB_PHI:          90.00 [deg]
GRB_THETA:        83.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       165.64d {+11h 02m 33s}   +6.14d {+06d 08' 11"}
SUN_DIST:         89.45 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       31.54d {+02h 06m 11s}   +8.56d {+08d 33' 36"}
MOON_DIST:        92.91 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       98.69, 29.79 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       90.00, 88.00 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_lc_medres34_bn200906550.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_locplot_all_bn200906550.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 was generated completely by automated pipeline processing.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(49.0<100sec) coincident with the SWIFT_BAT event (trignum=994856).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:12:50 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     994856,   Seg_Num: 0
GRB_RA:          272.2759d {+18h 09m 06.2s} (J2000),
                 272.2578d {+18h 09m 01.8s} (current),
                 272.3196d {+18h 09m 16.6s} (1950)
GRB_DEC:         +67.8795d {+67d 52' 46.1"} (J2000),
                 +67.8841d {+67d 53' 02.5"} (current),
                 +67.8683d {+67d 52' 06.0"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       35 [cnts]
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47530.81 SOD {13:12:10.81} UT,   66.7 [sec] since BAT Trigger Time
CENTROID_X:      313.97,  raw= 314  [pixels]
CENTROID_Y:      261.98,  raw= 262  [pixels]
ROLL:            287.68 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -85.12
GRB_POS_XRT_Z:   15.49
IMAGE_URL:       sw00994856000msxps_rw.img
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 19"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.48d {+02h 05m 55s}   +8.53d {+08d 31' 59"}
MOON_DIST:        92.54 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.91, 28.95 [deg] galactic lon,lat of the burst
ECL_COORDS:       57.29, 88.41 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:12:51 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     994856,   Seg_Num: 0
GRB_RA:          272.2759d {+18h 09m 06.2s} (J2000),
                 272.2578d {+18h 09m 01.8s} (current),
                 272.3196d {+18h 09m 16.6s} (1950)
GRB_DEC:         +67.8795d {+67d 52' 46.1"} (J2000),
                 +67.8841d {+67d 53' 02.5"} (current),
                 +67.8683d {+67d 52' 06.0"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       35 [cnts]
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47530.81 SOD {13:12:10.81} UT,   66.7 [sec] since BAT Trigger Time
CENTROID_X:      313.97,  raw= 314  [pixels]
CENTROID_Y:      261.98,  raw= 262  [pixels]
ROLL:            287.68 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -85.12
GRB_POS_XRT_Z:   15.49
IMAGE_URL:       sw00994856000msxps_rw.img
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 19"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.48d {+02h 05m 55s}   +8.53d {+08d 31' 59"}
MOON_DIST:        92.54 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.91, 28.95 [deg] galactic lon,lat of the burst
ECL_COORDS:       57.29, 88.41 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:12:39 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     994856,   Seg_Num: 0
GRB_RA:          272.2759d {+18h 09m 06.21s} (J2000),
                 272.2578d {+18h 09m 01.87s} (current),
                 272.3196d {+18h 09m 16.69s} (1950)
GRB_DEC:         +67.8795d {+67d 52' 46.1"} (J2000),
                 +67.8841d {+67d 53' 02.5"} (current),
                 +67.8683d {+67d 52' 06.0"} (1950)
GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       2.09e-08 [erg/cm2/sec]
GRB_SIGNIF:      5.91 [sigma]
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47530.81 SOD {13:12:10.81} UT,   66.7 [sec] since BAT Trigger Time
TAM[0-3]:        327.63 237.16 261.69 243.61
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 19"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.48d {+02h 05m 55s}   +8.53d {+08d 31' 57"}
MOON_DIST:        92.54 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.91, 28.95 [deg] galactic lon,lat of the burst
ECL_COORDS:       57.29, 88.41 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.68 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:14:59 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     994856,   Seg_Num: 0
GRB_RA:          272.293d {+18h 09m 10s} (J2000),
                 272.275d {+18h 09m 06s} (current),
                 272.336d {+18h 09m 21s} (1950)
GRB_DEC:         +67.852d {+67d 51' 08"} (J2000),
                 +67.857d {+67d 51' 24"} (current),
                 +67.841d {+67d 50' 27"} (1950)
GRB_DATE:        19098 TJD;   250 DOY;   20/09/06
GRB_TIME:        47464.07 SOD {13:11:04.07} UT
TRIGGER_INDEX:   473
GRB_PHI:         112.09 [deg]
GRB_THETA:         8.43 [deg]
DELTA_TIME:      -5.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.32 [sigma]
IMAGE_SIGNIF:    8.66 [sigma]
LC_URL:          sw00994856000msb.lc
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 17"}
SUN_DIST:         90.47 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.50d {+02h 05m 59s}   +8.54d {+08d 32' 24"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.94 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       56.53, 88.43 [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 = 74.57,20.35 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:15:23 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.251d {+18h 09m 00s} (J2000)
POINT_DEC:       +67.856d {+67d 51' 22"} (J2000)
POINT_ROLL:      287.685d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47540.59 SOD {13:12:20.59} UT,   76.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.268
N_STARS:         73
X_OFFSET:        360 [pixels]
Y_OFFSET:        624 [pixels]
X_MAX:           1319 [pixels]
Y_MAX:           1583 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00994856000msufc0076.fits
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 17"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.50d {+02h 06m 00s}   +8.54d {+08d 32' 29"}
MOON_DIST:        92.56 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.09, 88.44 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:15:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.251d {+18h 09m 00s} (J2000)
POINT_DEC:       +67.856d {+67d 51' 22"} (J2000)
POINT_ROLL:      287.685d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47540.59 SOD {13:12:20.59} UT,   76.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.268
N_STARS:         73
X_OFFSET:        360 [pixels]
Y_OFFSET:        624 [pixels]
X_MAX:           1319 [pixels]
Y_MAX:           1583 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00994856000msufc0076.fits
SUN_POSTN:       165.63d {+11h 02m 32s}   +6.14d {+06d 08' 16"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.50d {+02h 06m 01s}   +8.54d {+08d 32' 33"}
MOON_DIST:        92.56 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.09, 88.44 [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:     Sun 06 Sep 20 13:25:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
ROLL:            287.681d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47752.75 SOD {13:15:52.75} UT,   288.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     621090978
X_OFFSET:        851 [pixels]
Y_OFFSET:        1040 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       1200
BINNING_INDEX:   1
IM_URL:          sw00994856000msuni0314.fits
SUN_POSTN:       165.64d {+11h 02m 34s}   +6.14d {+06d 08' 08"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.57d {+02h 06m 18s}   +8.57d {+08d 34' 19"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [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 #28370
The Fermi GBM team reports the detection of a likely LONG GRB
At 13:11:53 UT on 6 Sep 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200906A (trigger 621090718.377264 / 200906550).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 270.0, Dec = 68.6 (J2000 degrees, equivalent to J2000 18h 00m, 68d 35'), with a statistical uncertainty of 4.1 degrees.
The angle from the Fermi LAT boresight is 83.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_skymap_all_bn200906550.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_healpix_all_bn200906550.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200906550/quicklook/glg_lc_medres34_bn200906550.gif

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:29:59 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
POINT_ROLL:      287.680d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  48330.58 SOD {13:25:30.58} UT,   866.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.266
N_STARS:         190
X_OFFSET:        291 [pixels]
Y_OFFSET:        480 [pixels]
X_MAX:           1730 [pixels]
Y_MAX:           1919 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00994856000msufc0866.fits
SUN_POSTN:       165.64d {+11h 02m 34s}   +6.13d {+06d 08' 03"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.61d {+02h 06m 27s}   +8.59d {+08d 35' 16"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:30:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
POINT_ROLL:      287.680d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  48330.58 SOD {13:25:30.58} UT,   866.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.266
N_STARS:         190
X_OFFSET:        291 [pixels]
Y_OFFSET:        480 [pixels]
X_MAX:           1730 [pixels]
Y_MAX:           1919 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00994856000msufc0866.fits
SUN_POSTN:       165.64d {+11h 02m 35s}   +6.13d {+06d 08' 03"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.61d {+02h 06m 27s}   +8.59d {+08d 35' 20"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [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:     Sun 06 Sep 20 13:31:24 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
ROLL:            287.680d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  48330.58 SOD {13:25:30.58} UT,   866.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     621091556
X_OFFSET:        850 [pixels]
Y_OFFSET:        1039 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1010
Y_GRB_POS:       1199
BINNING_INDEX:   1
IM_URL:          sw00994856000msuni0892.fits
SUN_POSTN:       165.64d {+11h 02m 35s}   +6.13d {+06d 08' 02"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.62d {+02h 06m 29s}   +8.59d {+08d 35' 32"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [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 Circular #28371
K. L. Page (U Leicester), D. N. Burrows (PSU), J.D. Gropp (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
At 13:11:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200906A (trigger=994856). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 272.293, +67.852 which is
```
   RA(J2000) = 18h 09m 10s
   Dec(J2000) = +67d 51' 08"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed two main peaks with a duration of about 80 sec. The second, larger, peak extends past the end of the slew and into the interval observed by XRT and UVOT. The peak count rate was ~3000 counts/sec (15-350 keV), at ~52 sec after the trigger.
The XRT began observing the field at 13:12:10.8 UT, 66.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 272.2731, 67.8791 which is equivalent to:
```
   RA(J2000)  = 18h 09m 05.54s
   Dec(J2000) = +67d 52' 44.8"
```
with an uncertainty of 2.6 arcseconds (radius, 90% containment). This location is 101 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 https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (5.25 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 5.5 (+6.91/-5.25) x 10^21 cm^-2 (90% confidence).
The initial flux in the 0.1 s image was 2.09e-08 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 76 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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/)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:31:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
ROLL:            287.680d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  48330.58 SOD {13:25:30.58} UT,   866.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     621091556
X_OFFSET:        850 [pixels]
Y_OFFSET:        1039 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1010
Y_GRB_POS:       1199
BINNING_INDEX:   1
IM_URL:          sw00994856000msuni0892.fits
SUN_POSTN:       165.64d {+11h 02m 35s}   +6.13d {+06d 08' 02"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.62d {+02h 06m 30s}   +8.59d {+08d 35' 35"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:24:34 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
ROLL:            287.681d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47752.75 SOD {13:15:52.75} UT,   288.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     621090978
X_OFFSET:        851 [pixels]
Y_OFFSET:        1040 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       1200
BINNING_INDEX:   1
IM_URL:          sw00994856000msuni0314.fits
SUN_POSTN:       165.64d {+11h 02m 34s}   +6.14d {+06d 08' 08"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.57d {+02h 06m 17s}   +8.57d {+08d 34' 14"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [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:     Sun 06 Sep 20 13:16:44 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.251d {+18h 09m 00s} (J2000)
POINT_DEC:       +67.856d {+67d 51' 22"} (J2000)
ROLL:            287.685d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47540.59 SOD {13:12:20.59} UT,   76.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     621090766
X_OFFSET:        851 [pixels]
Y_OFFSET:        1040 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       1200
BINNING_INDEX:   1
IM_URL:          sw00994856000msuni0102.fits
SUN_POSTN:       165.64d {+11h 02m 32s}   +6.14d {+06d 08' 16"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.51d {+02h 06m 02s}   +8.55d {+08d 32' 44"}
MOON_DIST:        92.56 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.09, 88.44 [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:     Sun 06 Sep 20 13:23:20 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
POINT_ROLL:      287.681d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47752.75 SOD {13:15:52.75} UT,   288.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.347
N_STARS:         35
X_OFFSET:        531 [pixels]
Y_OFFSET:        720 [pixels]
X_MAX:           1490 [pixels]
Y_MAX:           1679 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw00994856000msufc0288.fits
SUN_POSTN:       165.64d {+11h 02m 33s}   +6.14d {+06d 08' 09"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.56d {+02h 06m 14s}   +8.57d {+08d 33' 60"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 06 Sep 20 13:17:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.251d {+18h 09m 00s} (J2000)
POINT_DEC:       +67.856d {+67d 51' 22"} (J2000)
ROLL:            287.685d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47540.59 SOD {13:12:20.59} UT,   76.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     621090766
X_OFFSET:        851 [pixels]
Y_OFFSET:        1040 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       1200
BINNING_INDEX:   1
IM_URL:          sw00994856000msuni0102.fits
SUN_POSTN:       165.64d {+11h 02m 33s}   +6.14d {+06d 08' 15"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.51d {+02h 06m 03s}   +8.55d {+08d 32' 49"}
MOON_DIST:        92.56 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.95 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.09, 88.44 [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:     Sun 06 Sep 20 13:23:35 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     994856,   Seg_Num: 0
POINT_RA:        272.246d {+18h 08m 59s} (J2000)
POINT_DEC:       +67.858d {+67d 51' 30"} (J2000)
POINT_ROLL:      287.681d
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47752.75 SOD {13:15:52.75} UT,   288.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.347
N_STARS:         35
X_OFFSET:        531 [pixels]
Y_OFFSET:        720 [pixels]
X_MAX:           1490 [pixels]
Y_MAX:           1679 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw00994856000msufc0288.fits
SUN_POSTN:       165.64d {+11h 02m 33s}   +6.14d {+06d 08' 09"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.56d {+02h 06m 15s}   +8.57d {+08d 34' 03"}
MOON_DIST:        92.55 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.88, 28.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.19, 88.44 [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:     Sun 06 Sep 20 13:23:53 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     994856,   Seg_Num: 0
GRB_RA:          272.2730d {+18h 09m 05.52s} (J2000),
                 272.2549d {+18h 09m 01.18s} (current),
                 272.3166d {+18h 09m 15.99s} (1950)
GRB_DEC:         +67.8790d {+67d 52' 44.4"} (J2000),
                 +67.8835d {+67d 53' 00.7"} (current),
                 +67.8679d {+67d 52' 04.2"} (1950)
GRB_ERROR:       2.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19098 TJD;   250 DOY;   20/09/06
IMG_START_TIME:  47628.00 SOD {13:13:48.00} UT,   163.9 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       165.64d {+11h 02m 34s}   +6.14d {+06d 08' 09"}
SUN_DIST:         90.46 [deg]   Sun_angle= -7.1 [hr] (East of Sun)
MOON_POSTN:       31.56d {+02h 06m 15s}   +8.57d {+08d 34' 06"}
MOON_DIST:        92.53 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:       97.91, 28.95 [deg] galactic lon,lat of the burst
ECL_COORDS:       57.32, 88.42 [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 Circular #28372
S.Y. Fu, Z.P. Zhu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), X. Zhang, J.Z. Liu (XAO) report:
We observed the field of GRB 200906A (Page et al., GCN 28371) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We only obtained 2x120s frames in the Sloan r-band due to the cloudy weather, starting at 15:03:47 UT on 2020-09-06, i.e., 1.88 hr after the BAT trigger.
No optical source is detected in our stacked image at the XRT position (Page et al., GCN 28371), down to a limiting magnitude of r~19.3, calibrated with the nearby PanSTARRS field.
GCN Circular #28373
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 687 s of XRT Photon Counting mode data and 1 UVOT images for GRB 200906A, 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 = 272.27532, +67.88001 which is equivalent to:
```
RA (J2000): 18h 09m 6.08s
Dec (J2000): +67d 52' 48.1"
```
with an uncertainty of 1.9 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 #28374
R. Hamburg (UAH), C. Malacaria (NASA-MSFC/USRA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 13:11:53.38 UT on 06 September 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200906A (trigger 621090718 / 200906550) which was also detected by the Swift/BAT and Swift/XRT (Page et al. 2020, GCN 28371). The Fermi GBM Final Real-time Localization (GCN 28370) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 74 degrees.
The GBM light curve shows two peaks with a duration (T90) of about 67.3 s (50-300 keV), starting at T0-49 s. The time-averaged spectrum from T0-4.1 s to T0+16.4 s is best fit by a Band function with Epeak = 50.5 +/- 9.9 keV, alpha = -1.1 +/- 0.2 , and beta = -2.1 +/- 0.1
The event fluence (10-1000 keV) in this time interval is (3.9 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.8 s in the 10-1000 keV band is 4.5 +/- 0.2 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 #28375
A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (ASDC), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), P.A. Evans (U. Leicester) and K.L. Page report on behalf of the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 200906A (Page et al. GCN Circ. 28371), from 70 s to 41.5 ks after the BAT trigger. The data comprise 121 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. 28373).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.60 (+/-0.05).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.11 (+/-0.09). The best-fitting absorption column is 7.2 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 5.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.22 (+0.26, -0.24) and a best-fitting absorption column of 7.0 (+1.7, -1.5) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (8.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     7.0 (+1.7, -1.5) x 10^21 cm^-2
Galactic foreground: 5.2 x 10^20 cm^-2
Excess significance: 7.1 sigma
Photon index:	     2.22 (+0.26, -0.24)
```
If the light curve continues to decay with a power-law decay index of 0.60, the count rate at T+24 hours will be 0.013 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.2 x 10^-13 (1.1 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/00994856.
This circular is an official product of the Swift-XRT team.
GCN Circular #28376
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), and V. Casanova (IAA-CSIC) report:
We observed the location (Beardmore et al., GCN #28373) of the Swift GRB 200906A (Page et al., GCN #28371; GBM detection: Fermi GBM Team, GCN #28370, Hamburg et al., GCN #28374) with the 1.5m telescope of the Observatorio Sierra Nevada, in Granada, Spain. We obtained 78 x 100 s images beginning 2020-09-06 21:29:03.51 UT, after clouds had cleared.
In a stack of all images, centered at 0.39467 days after the GRB, no source is detected at the enhanced XRT position. Measured against two nearby USNO-B1.0 stars, we derive an upper limit of
Ic > 23.4 mag.
This agrees with the non-detection reported by Fu et al. (GCN #28372). We note the refined XRT analysis (Beardmore et al., GCN #28375) also reports an NH column density significantly exceeding the Galactic value, indicating this is a dark GRB.
GCN Circular #28377
H. Kumar (IITB), P. Dorje (IIA), V. Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA), report on behalf of the GROWTH-India collaboration:
We observed GRB200906A reported by Swift-BAT (K. L. Page et al., (GCN 28371), see also S.Y. Fu et al.,(GCN 28372), A.P. Beardmore
Et al., (GCN 28373), R. Hamburg et al., (GCN 28374) & D. A. Kann et al., (GCN 28376) with 0.7m GROWTH-India telescope. The field was observed in the SDSS r filter starting at 2020-09-06T16:34:48 UT i.e. ~ 3.33 hrs after the event detection by Swift-BAT. We didn’t find any new source within an uncertainty region of 1.9 arcsec around Ra(J2000) = 18:09:06.08, Dec(J2000) = +67:52:48.1 (GCN 28373) with an upper limit of*: *
r > 20.14 mag
(calibrated against PanSTARRs PS1 data release, Flewelling et al., 2018)
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).
GCN Circular #28379
GRB 200906A: Swift/UVOT Upper Limits
J. D. Gropp (PSU) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200906A 76 s after the BAT trigger (Page et al., GCN Circ. 28371). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 28373) 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            76          226          147         >21.2
u_FC               289          538          246         >20.4
white               76         5054          472         >21.3
v                  618         1413           97         >19.4
b                  544         4948          274         >20.1
u                  289         1487          324         >20.4
w1                 668         1462           97         >19.3
m2                 643         1438           78         >20.1
w2                 594         1389           97         >19.5
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #28380
S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), K. L. Page (U Leicester), 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 200906A (trigger #994856) (Page et al., GCN Circ. 28371). The BAT ground-calculated position is RA, Dec = 272.284, 67.887 deg which is
```
   RA(J2000)  =  18h 09m 08.2s
   Dec(J2000) = +67d 53' 13.4"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 97%.
The mask-weighted light curve shows a double-peaked structure. The first pulse starts at ~T-9 s and peaks at ~T+5 s. The second pulse starts at ~T+46 s, peaks at ~T+51 s, and ends at ~T+90 s. T90 (15-350 keV) is 70.90 +- 7.63 sec (estimated error including systematics).
The time-averaged spectrum from T-8.70 to T+90.01 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.00 +- 0.09. The fluence in the 15-150 keV band is 2.8 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+50.96 sec in the 15-150 keV band is 2.5 +- 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/994856/BA/
GCN Circular #28381
A. Rossi (INAF-OAS) reports on behalf of the CIBO collaboration:
We observed the location of the X-ray afterglow (Beardmore et al., GCN 28373) of the Swift GRB 200906A (Page et al., GCN 28371) simultaneously in the H and Ks bands with the LUCI near-infrared imager and spectrograph mounted on the Large Binocular Telescope (LBT, Mt Graham, AZ, USA). Observations started at 03:57 UT on 2020-09-07, and allowed us to obtain 18 min of exposure in each band. Unfortunately, observations were performed under variable sky conditions with passing clouds.
Inspection of the combined H-band images (mid-time of 0.628 days after the GRB), does not reveal any source down to the limiting magnitude H<21.8 mag (AB system).
A preliminary comparison of the simultaneous Swift/XRT flux of 1.06e-07 Jy at a mid-frequency 3.8E+17 Hz (1.6 keV), gives a X-ray to infrared slope-index b_OX<0.5, confirming the dark nature of this GRB. This XRT flux has been obtained modelling the XRT lightcurve after 200 seconds with a power-law with decay-index 0.60+-0.04.
We acknowledge the excellent support from the LBTO and LBT-INAF staff, particularly B. Rothberg, F. Cusano, S. Paiano and D. Paris, in obtaining these observations.
GCN Circular #28382
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), D. Reverte Paya (GTC) report:
We observed the field of GRB 200906A (Page et al., GCN #28371; GBM detection: Fermi GBM Team, GCN #28370; Hamburg et al., GCN #28374) with EMIR on the 10.4m GTC telescope, at the Roque de los Muchachos Observatory (La Palma, Spain). The observation consisted of H-band imaging with a total integration time of 955 s, and a mean epoch on the 6th of September at 23:57:35 UT (10.5753 hr after the Swift trigger).
No source is detected within the refined XRT error circle (Beardmore et al., GCN #28373) down to a 3-sigma limit of
H(AB) > 23.5 mag
This non detection is consistent with the previously reported limits (Fu et al., GCN#28372; Kann et al., GCN#28376; Kumar et al., GCN#28377; Gropp et al., GCN#28379; Rossi et al. GCN#28381) and confirms the dark nature of the burst.
GCN Circular #28386
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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 200906A ( Fermi GBM team, GCN 28370) errorbox 1 days 28040 sec after notice time and 1 days 28073 sec after trigger time at 2020-09-07 20:59:46 UT, with upper limit up to 18.7 mag. The observations began at zenith distance = 41 deg. The sun altitude is -39.4 deg.
The galactic latitude b = 30 deg., longitude l = 99 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1434684
We obtain a following upper limits.
```
Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

  114563 | 2020-09-07 20:59:46 |      MASTER-Tavrida | (18h 06m 25.68s , +67d 46m 47.4s) |   C |   180 | 18.6 |        
  114764 | 2020-09-07 21:03:07 |      MASTER-Tavrida | (18h 06m 28.97s , +67d 47m 45.3s) |   C |   180 | 18.7 |        
  114965 | 2020-09-07 21:06:28 |      MASTER-Tavrida | (18h 06m 23.16s , +67d 46m 55.2s) |   C |   180 | 18.6 |        
  115166 | 2020-09-07 21:09:49 |      MASTER-Tavrida | (18h 06m 25.23s , +67d 47m 41.8s) |   C |   180 | 18.7 |        
  115366 | 2020-09-07 21:13:09 |      MASTER-Tavrida | (18h 06m 30.87s , +67d 46m 28.9s) |   C |   180 | 18.7 |        
  115567 | 2020-09-07 21:16:30 |      MASTER-Tavrida | (18h 06m 25.58s , +67d 45m 15.3s) |   C |   180 | 18.6 |        
  115769 | 2020-09-07 21:19:52 |      MASTER-Tavrida | (18h 06m 32.36s , +67d 45m 24.9s) |   C |   180 | 18.6 |        
  115970 | 2020-09-07 21:23:13 |      MASTER-Tavrida | (18h 06m 30.08s , +67d 46m 46.7s) |   C |   180 | 18.6 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

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Jochen Greiner, last update: 07-Sep-2020 [Disclaimer]