Gamma-ray Burst 200528A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 28 May 20 10:27:39 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     974827,   Seg_Num: 0
GRB_RA:          176.637d {+11h 46m 33s} (J2000),
                 176.908d {+11h 47m 38s} (current),
                 175.967d {+11h 43m 52s} (1950)
GRB_DEC:         +58.147d {+58d 08' 50"} (J2000),
                 +58.034d {+58d 02' 01"} (current),
                 +58.425d {+58d 25' 30"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       1999 [cnts]    Image_Peak=149 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   41     E_range: 25-100 keV
BKG_INTEN:       21251 [cnts]
BKG_TIME:        37630.98 SOD {10:27:10.98} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37643.84 SOD {10:27:23.84} UT
GRB_PHI:         -131.96 [deg]
GRB_THETA:        27.68 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     15.39 [sigma]
IMAGE_SIGNIF:    9.17 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  +0  +0  +0 -13  +0 
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 03"}
SUN_DIST:         82.28 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.28d {+09h 17m 06s}  +19.85d {+19d 50' 47"}
MOON_DIST:        46.97 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.62, 56.96 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      145.19, 50.09 [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 = 222.06,20.22 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(1.0<100sec) coincident with the FERMI_GBM event (trignum=612354449).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:27:48 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      46
TRIGGER_NUM:     612354449
GRB_RA:          148.550d {+09h 54m 12s} (J2000),
                 148.894d {+09h 55m 35s} (current),
                 147.702d {+09h 50m 48s} (1950)
GRB_DEC:         +54.567d {+54d 34' 00"} (J2000),
                 +54.470d {+54d 28' 11"} (current),
                 +54.803d {+54d 48' 11"} (1950)
GRB_ERROR:       11.30 [deg radius, statistical plus systematic]
GRB_INTEN:       147 [cnts/sec]
DATA_SIGNIF:     10.80 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:          20.00 [deg]
GRB_THETA:        30.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      1.14
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       1,0,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 03"}
SUN_DIST:         68.67 [deg]   Sun_angle= -5.5 [hr] (East of Sun)
MOON_POSTN:      139.28d {+09h 17m 06s}  +19.85d {+19d 50' 46"}
MOON_DIST:        35.39 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      160.01, 47.80 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      129.42, 38.85 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.52,-0.70 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:27:57 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      59
TRIGGER_NUM:     612354449
GRB_RA:          156.750d {+10h 27m 00s} (J2000),
                 157.085d {+10h 28m 20s} (current),
                 155.923d {+10h 23m 41s} (1950)
GRB_DEC:         +58.967d {+58d 58' 00"} (J2000),
                 +58.862d {+58d 51' 44"} (current),
                 +59.222d {+59d 13' 18"} (1950)
GRB_ERROR:       9.35 [deg radius, statistical plus systematic]
GRB_INTEN:       155 [cnts/sec]
DATA_SIGNIF:     16.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:          12.00 [deg]
GRB_THETA:        25.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.86
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      85%  GRB
2nd_MOST_LIKELY:  13%  Generic SGR
DETECTORS:       1,0,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 03"}
SUN_DIST:         72.33 [deg]   Sun_angle= -6.1 [hr] (East of Sun)
MOON_POSTN:      139.28d {+09h 17m 07s}  +19.85d {+19d 50' 44"}
MOON_DIST:        41.09 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      150.88, 49.59 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      131.92, 44.85 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.52,-0.70 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:28:10 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     612354449
GRB_RA:          173.320d {+11h 33m 17s} (J2000),
                 173.606d {+11h 34m 26s} (current),
                 172.613d {+11h 30m 27s} (1950)
GRB_DEC:         +62.660d {+62d 39' 36"} (J2000),
                 +62.547d {+62d 32' 50"} (current),
                 +62.936d {+62d 56' 11"} (1950)
GRB_ERROR:       5.09 [deg radius, statistical only]
DATA_SIGNIF:     17.20 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:         357.00 [deg]
GRB_THETA:        18.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 03"}
SUN_DIST:         78.76 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
MOON_POSTN:      139.28d {+09h 17m 07s}  +19.85d {+19d 50' 43"}
MOON_DIST:        48.75 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      137.45, 52.21 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      138.59, 52.54 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_612354449.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
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(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:28:24 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      87
TRIGGER_NUM:     612354449
GRB_RA:          169.150d {+11h 16m 36s} (J2000),
                 169.454d {+11h 17m 49s} (current),
                 168.400d {+11h 13m 36s} (1950)
GRB_DEC:         +63.450d {+63d 27' 00"} (J2000),
                 +63.338d {+63d 20' 18"} (current),
                 +63.723d {+63d 43' 23"} (1950)
GRB_ERROR:       5.30 [deg radius, statistical plus systematic]
GRB_INTEN:       695 [cnts/sec]
DATA_SIGNIF:     35.90 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:        20.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      1.91
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      85%  GRB
2nd_MOST_LIKELY:  14%  Generic SGR
DETECTORS:       1,0,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 04"}
SUN_DIST:         76.72 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      139.28d {+09h 17m 08s}  +19.84d {+19d 50' 41"}
MOON_DIST:        48.07 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      139.36, 50.55 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      135.39, 51.93 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.52,-0.70 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:28:31 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      90
TRIGGER_NUM:     612354449
GRB_RA:          166.800d {+11h 07m 12s} (J2000),
                 167.103d {+11h 08m 25s} (current),
                 166.052d {+11h 04m 12s} (1950)
GRB_DEC:         +58.567d {+58d 34' 00"} (J2000),
                 +58.456d {+58d 27' 22"} (current),
                 +58.837d {+58d 50' 14"} (1950)
GRB_ERROR:       4.82 [deg radius, statistical plus systematic]
GRB_INTEN:       620 [cnts/sec]
DATA_SIGNIF:     63.90 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:          15.00 [deg]
GRB_THETA:        20.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      2.07
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      76%  GRB
2nd_MOST_LIKELY:  23%  Generic SGR
DETECTORS:       1,0,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 04"}
SUN_DIST:         77.43 [deg]   Sun_angle= -6.8 [hr] (East of Sun)
MOON_POSTN:      139.28d {+09h 17m 08s}  +19.84d {+19d 50' 40"}
MOON_DIST:        43.57 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      145.70, 53.71 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      138.53, 47.35 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 191.52,-0.70 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:28:47 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      0
TRIGGER_NUM:     612354449
GRB_RA:          173.530d {+11h 34m 07s} (J2000),
                 173.818d {+11h 35m 16s} (current),
                 172.819d {+11h 31m 17s} (1950)
GRB_DEC:         +64.730d {+64d 43' 48"} (J2000),
                 +64.617d {+64d 37' 02"} (current),
                 +65.006d {+65d 00' 23"} (1950)
GRB_ERROR:       2.73 [deg radius, statistical only]
DATA_SIGNIF:     17.90 [sigma]
DATA_INTERVAL:   6.144 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:         351.00 [deg]
GRB_THETA:        19.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 04"}
SUN_DIST:         77.96 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
MOON_POSTN:      139.29d {+09h 17m 09s}  +19.84d {+19d 50' 38"}
MOON_DIST:        50.29 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      135.75, 50.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      136.41, 54.15 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_612354449.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
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(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:28:58 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      1
TRIGGER_NUM:     612354449
GRB_RA:          173.600d {+11h 34m 24s} (J2000),
                 173.888d {+11h 35m 33s} (current),
                 172.889d {+11h 31m 33s} (1950)
GRB_DEC:         +64.800d {+64d 47' 60"} (J2000),
                 +64.687d {+64d 41' 13"} (current),
                 +65.076d {+65d 04' 35"} (1950)
GRB_ERROR:       2.05 [deg radius, statistical only]
DATA_SIGNIF:     21.60 [sigma]
DATA_INTERVAL:   10.240 [sec]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:         351.00 [deg]
GRB_THETA:        19.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 04"}
SUN_DIST:         77.96 [deg]   Sun_angle= -7.2 [hr] (East of Sun)
MOON_POSTN:      139.29d {+09h 17m 09s}  +19.84d {+19d 50' 36"}
MOON_DIST:        50.36 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      135.66, 50.38 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      136.36, 54.22 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_612354449.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
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(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 28 May 20 10:36:59 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     612354449
GRB_RA:          169.220d {+11h 16m 53s} (J2000),
                 169.518d {+11h 18m 04s} (current),
                 168.485d {+11h 13m 56s} (1950)
GRB_DEC:         +60.190d {+60d 11' 24"} (J2000),
                 +60.078d {+60d 04' 42"} (current),
                 +60.463d {+60d 27' 47"} (1950)
GRB_ERROR:       1.00 [deg radius, statistical only]
GRB_DATE:        18997 TJD;   149 DOY;   20/05/28
GRB_TIME:        37644.35 SOD {10:27:24.35} UT
GRB_PHI:           9.00 [deg]
GRB_THETA:        19.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        65.77d {+04h 23m 05s}  +21.57d {+21d 34' 07"}
SUN_DIST:         77.97 [deg]   Sun_angle= -6.9 [hr] (East of Sun)
MOON_POSTN:      139.37d {+09h 17m 28s}  +19.83d {+19d 49' 31"}
MOON_DIST:        45.60 [deg]
MOON_ILLUM:      32 [%]
GAL_COORDS:      142.38, 53.22 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      138.61, 49.38 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_locplot_all_bn200528436.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:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=974827).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 22 May 20 11:45:23 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     973628,   Seg_Num: 0
GRB_RA:            5.667d {+00h 22m 40s} (J2000),
                   5.928d {+00h 23m 43s} (current),
                   5.026d {+00h 20m 06s} (1950)
GRB_DEC:          -0.282d {-00d 16' 53"} (J2000),
                  -0.169d {-00d 10' 06"} (current),
                  -0.559d {-00d 33' 31"} (1950)
GRB_DATE:        18991 TJD;   143 DOY;   20/05/22
GRB_TIME:        42094.12 SOD {11:41:34.12} UT
TRIGGER_INDEX:   122
GRB_PHI:         170.50 [deg]
GRB_THETA:        24.82 [deg]
DELTA_TIME:      -70.00 [sec]
TRIGGER_DUR:     0.128 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     30.62 [sigma]
IMAGE_SIGNIF:    9.79 [sigma]
LC_URL:          sw00973628000msb.lc
SUN_POSTN:        59.75d {+03h 58m 59s}  +20.53d {+20d 31' 41"}
SUN_DIST:         56.51 [deg]   Sun_angle= 3.6 [hr] (West of Sun)
MOON_POSTN:       57.53d {+03h 50m 07s}  +17.34d {+17d 20' 38"}
MOON_DIST:        53.70 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      107.32,-62.28 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        5.09, -2.51 [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 = 353.33,-8.35 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 28 May 20 10:29:12 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     974827,   Seg_Num: 0
GRB_RA:          176.6438d {+11h 46m 34.5s} (J2000),
                 176.9155d {+11h 47m 39.7s} (current),
                 175.9742d {+11h 43m 53.8s} (1950)
GRB_DEC:         +58.1921d {+58d 11' 31.5"} (J2000),
                 +58.0787d {+58d 04' 43.2"} (current),
                 +58.4699d {+58d 28' 11.7"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       63 [cnts]
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37713.98 SOD {10:28:33.98} UT,   70.1 [sec] since BAT Trigger Time
CENTROID_X:      245.69,  raw= 246  [pixels]
CENTROID_Y:      248.94,  raw= 249  [pixels]
ROLL:            298.74 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -115.87
GRB_POS_XRT_Z:   -145.44
IMAGE_URL:       sw00974827000msxps_rw.img
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 04"}
SUN_DIST:         82.27 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.29d {+09h 17m 10s}  +19.84d {+19d 50' 34"}
MOON_DIST:        47.00 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.58, 56.92 [deg] galactic lon,lat of the burst
ECL_COORDS:      145.15, 50.12 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 28 May 20 10:28:59 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     974827,   Seg_Num: 0
GRB_RA:          176.6438d {+11h 46m 34.51s} (J2000),
                 176.9155d {+11h 47m 39.72s} (current),
                 175.9742d {+11h 43m 53.81s} (1950)
GRB_DEC:         +58.1921d {+58d 11' 31.5"} (J2000),
                 +58.0787d {+58d 04' 43.2"} (current),
                 +58.4699d {+58d 28' 11.7"} (1950)
GRB_ERROR:       5.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       4.08e-08 [erg/cm2/sec]
GRB_SIGNIF:      7.93 [sigma]
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37713.98 SOD {10:28:33.98} UT,   70.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.61 237.20 261.57 243.63
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 04"}
SUN_DIST:         82.27 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.29d {+09h 17m 09s}  +19.84d {+19d 50' 36"}
MOON_DIST:        47.00 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.58, 56.92 [deg] galactic lon,lat of the burst
ECL_COORDS:      145.15, 50.12 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 2.71 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 28 May 20 10:31:35 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     974827,   Seg_Num: 0
POINT_RA:        176.678d {+11h 46m 43s} (J2000)
POINT_DEC:       +58.144d {+58d 08' 37"} (J2000)
POINT_ROLL:      298.732d
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37724.04 SOD {10:28:44.04} UT,   80.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.619
N_STARS:         61
X_OFFSET:        584 [pixels]
Y_OFFSET:        424 [pixels]
X_MAX:           1543 [pixels]
Y_MAX:           1383 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00974827000msufc0080.fits
SUN_POSTN:        65.77d {+04h 23m 04s}  +21.57d {+21d 34' 05"}
SUN_DIST:         82.30 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.31d {+09h 17m 15s}  +19.84d {+19d 50' 15"}
MOON_DIST:        46.98 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.59, 56.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      145.22, 50.10 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 28 May 20 10:29:16 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     974827,   Seg_Num: 0
GRB_RA:          176.6438d {+11h 46m 34.5s} (J2000),
                 176.9155d {+11h 47m 39.7s} (current),
                 175.9742d {+11h 43m 53.8s} (1950)
GRB_DEC:         +58.1921d {+58d 11' 31.5"} (J2000),
                 +58.0787d {+58d 04' 43.2"} (current),
                 +58.4699d {+58d 28' 11.7"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       63 [cnts]
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37713.98 SOD {10:28:33.98} UT,   70.1 [sec] since BAT Trigger Time
CENTROID_X:      245.69,  raw= 246  [pixels]
CENTROID_Y:      248.94,  raw= 249  [pixels]
ROLL:            298.74 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -115.87
GRB_POS_XRT_Z:   -145.44
IMAGE_URL:       sw00974827000msxps_rw.img
SUN_POSTN:        65.76d {+04h 23m 03s}  +21.57d {+21d 34' 04"}
SUN_DIST:         82.27 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.29d {+09h 17m 10s}  +19.84d {+19d 50' 34"}
MOON_DIST:        47.00 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.58, 56.92 [deg] galactic lon,lat of the burst
ECL_COORDS:      145.15, 50.12 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN Circular #27831
The Fermi GBM team reports the detection of a likely LONG GRB
At 10:27:24 UT on 28 May 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200528A (trigger 612354449.346938 / 200528436).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 169.2, Dec = 60.2 (J2000 degrees, equivalent to J2000 11h 16m, 60d 12'), with a statistical uncertainty of 1.0 degrees.
The angle from the Fermi LAT boresight is 19.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_skymap_all_bn200528436.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/bn200528436/quicklook/glg_healpix_all_bn200528436.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200528436/quicklook/glg_lc_medres34_bn200528436.gif
GCN Circular #27832
E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC), P. A. Evans (U Leicester), J.D. Gropp (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), F. E. Marshall (NASA/GSFC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team:
At 10:27:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200528A (trigger=974827). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 176.637, +58.147 which is
```
   RA(J2000) = 11h 46m 33s
   Dec(J2000) = +58d 08' 50"
```
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 60 sec. The peak count rate was ~19000 counts/sec (15-350 keV), at ~33 sec after the trigger.
The XRT began observing the field at 10:28:33.9 UT, 70.2 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 176.6438, 58.1921 which is equivalent to:
```
   RA(J2000)  = 11h 46m 34.51s
   Dec(J2000) = +58d 11' 31.6"
```
with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 162 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.
The initial flux in the 0.1 s image was 4.08e-08 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 80 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 0.01.
Burst Advocate for this burst is E. Ambrosi (elena.ambrosi AT inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 28 May 20 10:31:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     974827,   Seg_Num: 0
POINT_RA:        176.678d {+11h 46m 43s} (J2000)
POINT_DEC:       +58.144d {+58d 08' 37"} (J2000)
POINT_ROLL:      298.732d
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37724.04 SOD {10:28:44.04} UT,   80.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.619
N_STARS:         61
X_OFFSET:        584 [pixels]
Y_OFFSET:        424 [pixels]
X_MAX:           1543 [pixels]
Y_MAX:           1383 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00974827000msufc0080.fits
SUN_POSTN:        65.77d {+04h 23m 04s}  +21.57d {+21d 34' 05"}
SUN_DIST:         82.30 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.32d {+09h 17m 16s}  +19.84d {+19d 50' 13"}
MOON_DIST:        46.98 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.59, 56.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      145.22, 50.10 [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:     Thu 28 May 20 10:36:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1703945,   Seg_Num: 0
POINT_RA:          0.000d {+00h 00m 00s} (J2000)
POINT_DEC:        +0.000d {+00d 00' 00"} (J2000)
ROLL:            0.000d
IMG_START_DATE:  27108 TJD;   8260 DOY;   20/34/5894495
IMG_START_TIME:  56655.12 SOD {15:44:15.12} UT,   19011.3 [sec] since BAT Trigger Time
FILTER:          2, UVW2
EXPOSURE_ID:     623450917
X_OFFSET:        658 [pixels]
Y_OFFSET:        1172 [pixels]
WIDTH:           1184 [pixels]
HEIGHT:          1317 [pixels]
X_GRB_POS:       658
Y_GRB_POS:       1168
BINNING_INDEX:   4
IM_URL:          sw00974827000msuni0317.fits
SUN_POSTN:        65.77d {+04h 23m 05s}  +21.57d {+21d 34' 07"}
SUN_DIST:         66.97 [deg]   Sun_angle= 4.3 [hr] (West of Sun)
MOON_POSTN:      139.36d {+09h 17m 26s}  +19.83d {+19d 49' 37"}
MOON_DIST:       134.95 [deg]
MOON_ILLUM:      32 [%]
GAL_COORDS:       96.34,-60.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        0.00,  0.00 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The Pointing RA,Dec,Roll values came from the 1st Image Notice.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 16x16 binning (compression).  
COMMENTS:        This notice was forced out after watchdog timer expiring -- most likely due to missing packet(s);  
COMMENTS:        as a consequence some of the fields may be incoorect (eg TRIGGER_NUM,RA,DEC).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 28 May 20 10:32:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     974827,   Seg_Num: 0
POINT_RA:        176.678d {+11h 46m 43s} (J2000)
POINT_DEC:       +58.144d {+58d 08' 37"} (J2000)
ROLL:            298.732d
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37724.04 SOD {10:28:44.04} UT,   80.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     612354549
X_OFFSET:        1164 [pixels]
Y_OFFSET:        938 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1324
Y_GRB_POS:       1098
BINNING_INDEX:   1
IM_URL:          sw00974827000msuni0106.fits
SUN_POSTN:        65.77d {+04h 23m 04s}  +21.57d {+21d 34' 05"}
SUN_DIST:         82.30 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.33d {+09h 17m 18s}  +19.83d {+19d 50' 04"}
MOON_DIST:        46.97 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.59, 56.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      145.22, 50.10 [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:     Thu 28 May 20 10:33:20 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     974827,   Seg_Num: 0
POINT_RA:        176.678d {+11h 46m 43s} (J2000)
POINT_DEC:       +58.144d {+58d 08' 37"} (J2000)
ROLL:            298.732d
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37724.04 SOD {10:28:44.04} UT,   80.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     612354549
X_OFFSET:        1164 [pixels]
Y_OFFSET:        938 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1324
Y_GRB_POS:       1098
BINNING_INDEX:   1
IM_URL:          sw00974827000msuni0106.fits
SUN_POSTN:        65.77d {+04h 23m 04s}  +21.57d {+21d 34' 06"}
SUN_DIST:         82.30 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.33d {+09h 17m 19s}  +19.83d {+19d 50' 01"}
MOON_DIST:        46.97 [deg]
MOON_ILLUM:      31 [%]
GAL_COORDS:      138.59, 56.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      145.22, 50.10 [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:     Thu 28 May 20 10:34:17 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     974827,   Seg_Num: 0
POINT_RA:        176.678d {+11h 46m 43s} (J2000)
POINT_DEC:       +58.144d {+58d 08' 37"} (J2000)
POINT_ROLL:      298.732d
IMG_START_DATE:  18997 TJD;   149 DOY;   20/05/28
IMG_START_TIME:  37935.82 SOD {10:32:15.82} UT,   292.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.020
N_STARS:         6
X_OFFSET:        844 [pixels]
Y_OFFSET:        618 [pixels]
X_MAX:           1803 [pixels]
Y_MAX:           1577 [pixels]
DET_THRESH:      3
PHOTO_THRESH:    2
SL_URL:          sw00974827000msufc0291.fits
SUN_POSTN:        65.77d {+04h 23m 04s}  +21.57d {+21d 34' 06"}
SUN_DIST:         82.30 [deg]   Sun_angle= -7.4 [hr] (East of Sun)
MOON_POSTN:      139.34d {+09h 17m 22s}  +19.83d {+19d 49' 53"}
MOON_DIST:        46.97 [deg]
MOON_ILLUM:      32 [%]
GAL_COORDS:      138.59, 56.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      145.22, 50.10 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN Circular #27833
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), and D. A. Kann (HETH/IAA-CSIC) report:
Within the XRT error circle of GRB 200528A (Fermi GBM team, GCN #27831; Ambrosi et al., GCN #27832), a bright, extended object is detected, at position (J2000, from SDSS):
```
RA = 176.64297
Dec. = 58.19313
```
It is found to have (from SDSS):
```
u' = 22.28 +/-0.42 mag;
g' = 21.46 +/- 0.075 mag;
r' = 20.45 +/- 0.047 mag;
i' = 20.13 +/- 0.052 mag;
z' = 19.88 +/- 0.147 mag.
```
It is also detected in PanSTARRS and WISE with W1 = 16.7 +/- 0.1 mag.
The photometric redshift in SDSS is given as z = 0.380 +/- 0.0792.
We suggest this galaxy to be the host galaxy of GRB 200528A. The early non-detection in UVOT indicates this might be an optically dark GRB, as the X-ray light curve is very bright early on. The X-ray column density is unknown so far (Ambrosi et al., GCN #27832) but likely to be high.
Confirmation or rejection awaits a refined XRT position once data are obtainable in PC mode.
GCN Circular #27834
R. Adachi, R. Hosokawa, K. L. Murata, M. Niwano, F. Ogawa, N. Nakamura, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 200528A (Fermi GBM team, GCN #27831; Ambrosi et al., GCN #27832) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescopes of Akeno Observatory in Japan.
The observation started on 10:28:31.87 UT. The first 40 images were heavily affected by twilight and bad weather at Akeno Observatory. We checked single images and combined images. We did not find any new point sources within the Swift/XRT error circle (Ambrosi et al., GCN #27832) in all three bands. Also, we did not detect the potential host galaxy (de Ugarte Postigo et al., GCN #27833) due to shallow upper limits of our observation. We obtained the 5-sigma limits as follows.
```
T0+[min] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
36.7 11:28:34 1020 g'>18.9, Rc>18.3, Ic>17.4
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used the UCAC4 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al., submitted; https://github.com/MNiwano/Eclair).
GCN Circular #27835
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),
H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
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-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the Swift GRB 200528A ( E. Ambrosi et al., GCN 27832) errorbox 9786 sec after notice time and 9804 sec after trigger time at 2020-05-28 13:10:47 UT, with upper limit up to 16.7 mag. Observations started at twilight. The observations began at zenith distance = 22 deg. The sun altitude is -12.3 deg.
The galactic latitude b = 57 deg., longitude l = 138 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1368165
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

    9894 |         MASTER-Amur |   C |   180 | 16.7 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #27836
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 910 s of XRT Photon Counting mode data and 3 UVOT images for GRB 200528A, 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 = 176.63744, +58.19257 which is equivalent to:
```
RA (J2000): 11h 46m 32.99s
Dec (J2000): +58d 11' 33.3"
```
with an uncertainty of 1.8 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 #27837
Z.P. Zhu, S.Y. Fu, 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 2005528A (Ambrosi et al., GCN 27832) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained 5x120s frames in the Sloan r-band, starting at 15:55:41 UT on 2020-05-28, i.e., 5.47 hr after the burst.
No optical source is detected in our stacked image at the enhanced XRT position (Evans et al., GCN 27836), down to a limiting magnitude of r~20.1, calibrated with nearby SDSS field.
GCN Circular #27838
A. Kumar (ARIES), S. B. Pandey (ARIES), R. Gupta (ARIES), K. Misra (ARIES), A. Aryan (ARIES), A. Ghosh (ARIES), and Dimple (ARIES) report:
We carried out observation of Fermi GBM detected GRB 200528A (GCN 27831, Ambrosi et al., GCN 27832) with the 1.3m Devasthal Fast Optical Telescope (DFOT) at Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), India.
The observation was started on 2020-05-28T15:37:05 UTC. We observed a series of 4 x 300s exposures using the Bessell I filter covering Swift XRT enhanced position (Evans et al., 27836).
We do not detect any new optical source within the Swift XRT enhanced error circle in individual as well as in the stacked image (Adachi et al., GCN 27834, Lipunov et al., GCN 27835 and Zhu et al., GCN 27837).
We obtained the 3-sigma upper limit as follows:
```
T_start-T0(hrs) Start Date (UTC)  End Date (UTC)   Filter  Limit (mag)
-----------------------------------------------------------------------------------------------
5.161    2020-05-28T15:37:05  2020-05-28T15:58:42   I     20.2 +- 0.2
```
Photometry is done based on the USNO-B1.0 catalog. This magnitude is not corrected for Galactic extinction in the direction of the GRB.
GCN Circular #27839
S. D. Barthelmy (GSFC), E. Ambrosi (INAF-IASFPA), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), 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-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200528A (trigger #974827) (Ambrosi, et al., GCN Circ. 27832). The BAT ground-calculated position is RA, Dec = 176.637, 58.185 deg which is
```
  RA(J2000)  =  11h 46m 32.8s 
  Dec(J2000) = +58d 11' 07.3" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 62%.
The mask-weighted light curve shows a multi-peaked structure rising just before T0, peaking around T+35 sec and decaying to background by T+120 sec. T90 (15-350 keV) is 58.7 +- 1.4 sec (estimated error including systematics).
The time-averaged spectrum from T-1.02 to T+112.88 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.62 +- 0.14, and Epeak of 40.1 +- 5.5 keV (chi squared 25.28 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.8 +- 0.0 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+33.82 sec in the 15-150 keV band is 17.5 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.14 +- 0.03 (chi squared 69.65 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/974827/BA/
GCN Circular #27840
F. E. Marshall (NASA/GSFC) and E. Ambrosi (INAF-IASFPA) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200528A 81 s after the BAT trigger (Ambrosi et al., GCN Circ. 27832). No optical afterglow consistent with the enhanced XRT position (Evans et al. GCN Circ. 27836) 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            81          231          147         >21.1
u                  293          305           12         >18.7
v                 5743         5942          197         >18.8
b                 5127         5327          169         >20.7
uvw2              5538         5738          197         >21.0
```
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 #27841
C. Fletcher (USRA), A. von Kienlin and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 10:27:24.35 UT on 28 May 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200528A (trigger 612354449 / 200528436) which was also detected by the Swift/BAT (Ambrosi et al. 2020, GCN 27832) The Fermi GBM Final Real-time Localization (GCN 27831) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 16 degrees.
The GBM light curve shows multiple peaks with a duration (T90) of about 56 s (50-300 keV). The time-averaged spectrum from T0+2.05 s to T0+59.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.39 +/- 0.02 and the cutoff energy, parameterized as Epeak, is 55.5 +/- 0.8 keV.
The event fluence (10-1000 keV) in this time interval is (2.54 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+33.3 s in the 10-1000 keV band is 27.2 +/- 0.4 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 #27842
D. B. Malesani (DTU Space), J. P. U. Fynbo (DAWN/NBI), L. Izzo (DARK/NBI), D. Xu (NAOC/CAS), T. Pursimo (NOT), report on behalf of a larger collaboration:
We observed the field of GRB 200528A (Ambrosi et al., GCN 27832) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations were carried out under variable, thin clouds. After stacking the good images in each filter, no afterglow is visible in either band within the XRT position (Evans et al., GCN 27836). At mean epochs May 28.926 and 28.927 UT (11.78 and 11.80 hr after the GRB, respectively), we derive limiting magnitudes r > 23.5 and z > 22 AB (calibrated against nearby stars in the Pan-STARRS catalog).
We note that the galaxy visible in the archival surveys and noted by de Ugarte Postigo & Kann (GCN 27833) is about 10.6 arcsec away of the UVOT-enhanced XRT position (1.5" error; Evans et al., GCN 27836), and is thus likely unrelated to the GRB.
GCN Circular #27849
S. Belkin (IKI), V. Kim (AFIF, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (AFIF), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of larger GRB IKI FuN collaboration:
We observed GRB 200528A (Fermi GBM Team GCN 27831; Ambrosi et al., GCN 27832) with AZT-20 1.5 m telescope of Assy-Turgen observatory starting on May., 28 (UT) 16:16:12. We do not detect any sources in the Swift-XRT extended position (Evans et al., GCN 27836).
Preliminary photometry of the field is following.
```
Date       UT start   t-T0       Filter Exp.   OT   Err.   UL (3sigma)
                       (mid, days)        (s)

2020-05-28 16:16:12   0.26777    r(AB)  54*60  n/d  n/d    22.4
```
The photometry is based on the nearby stars of SDSS catalog
```
SDSS-DR12_id        r
J114613.33+581329.5 19.455
J114632.90+581307.2 19.190
J114549.81+581044.3 19.004
J114600.53+580839.6 16.985
```
GCN Circular #27852
M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and E. Ambrosi report on behalf of the Swift-XRT team:
We have analysed 5.7 ks of XRT data for GRB 200528A (Ambrosi et al. GCN Circ. 27832), from 73 s to 50.9 ks after the BAT trigger. The data comprise 226 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 27836).
The late-time light curve (from T0+5.1 ks) can be modelled with a power-law decay with a decay index of alpha=0.97 (+/-0.07).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.30 (+/-0.05). The best-fitting absorption column is 3.63 (+0.19, -0.18) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.24 (+0.16, -0.15) and a best-fitting absorption column of 3.8 (+0.7, -0.6) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (6.1 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.8 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 1.2 x 10^20 cm^-2
Excess significance: 9.8 sigma
Photon index:	     2.24 (+0.16, -0.15)
```
If the light curve continues to decay with a power-law decay index of 0.97, the count rate at T+24 hours will be 0.041 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x 10^-12 (2.5 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00974827.
This circular is an official product of the Swift-XRT team.
GCN Circular #27855
V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
The long soft GRB 200528A (Swift detection: Ambrosi et al., GCN Circ. 27832, Barthelmy et al., GCN Circ. 27839; Fermi GBM observation: Fletcher and Meegan, GCN Circ. 27841; https://gcn.gsfc.nasa.gov/other/200528A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 10:27:27.087 UTC on 28 May 2020. The burst signal was seen by all CGBM detectors. Because of a problem in one of the ground alert processing script, the GCN notice was not distributed automatically for this event.
The burst light curve shows a multi-peaked structure which starts at T-4.5 sec, peaks at T+30.8 sec and ends at T+35.1 sec. The T90 and T50 durations measured by the SGM data are 36.6 +- 3.2 sec and 27.9 +- 4.0 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1274696855/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #27860
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), M. Blazek, C. C. Thoene, J. F. Agui Fernandez (all HETH/IAA-CSIC), and I. Hermelo (CAHA) report:
We observed the XRT error circle (Evans et al., GCN #27836) of the bright GRB 200528A (Swift detection: Ambrosi et al., GCN #27832; Fermi GBM detection: The Fermi GBM team, GCN #27831) with the 2.2m telescope at CAHA (Almeria, Spain), equipped with the CAFOS detector. We obtained 21 x 180 s exposures in the Ic band under adverse observing conditions (moonlight, bad seeing and transparency).
At the enhanced XRT position, we detect no source (but would have preferred to). We derive a 3 sigma limiting magnitude of Ic > 23.5 mag (Vega) at 0.440865 days after the GRB, calibrated against SDSS standard stars transformed to the Ic band following Lupton (2005). This limit is comparable to those achieved by NOT about an hour later (Malesani et al., GCN #27842).
GCN Circular #27883
A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Ridnaia and T. Cline on behalf of the Konus-Wind team, report:
The long-duration, soft-spectrum GRB200528A (Swift detection: Ambrosi et al., GCN 27832; Barthelmy et al., GCN 27839; Fermi GBM Observation: Fletcher, von Kienlin & Meegan, GCN 27841; CALET Gamma-Ray Burst Monitor detection: Pal'shin et al., GCN 27855) triggered Konus-Wind at T0=37675.256 s UT (10:27:55.256).
The burst light curve shows a complex structure which starts at ~T0-33.8 s, with a total duration of~60.0 s, and comprises two double-peaked emission episodes. The emission is seen up to ~1 MeV.
As observed by Konus-Wind, the burst had a fluence of 2.12(-0.07,+0.07)x10^-5 erg/cm2, and a 64-ms peak energy flux, measured from T0+1.696 s, of 2.38(-0.35,+0.35)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+33.024 s) is best fit in the 20 keV - 1 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with� alpha = -1.41(-0.14,+0.14), and Ep = 64(-5,+5) keV (chi2 = 50/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.89 (chi2 = 49/59 dof).
The spectrum near the peak count rate (measured from T0+0.256 to T0+8.448 s) is best fit in the 20 keV - 1 MeV range by the power law with exponential cutoff model with� alpha = -1.14(-0.15,+0.16), and Ep = 75(-4,+5) keV (chi2 = 52/60 dof). Fitting by the GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.03 (chi2 = 51/59 dof).
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB200528_T37675/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.

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Jochen Greiner, last update: 02-Jun-2020 [Disclaimer]