Gamma-ray Burst 120521B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 May 12 09:08:24 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     359284074
GRB_RA:          216.017d {+14h 24m 04s} (J2000),
                 216.221d {+14h 24m 53s} (current),
                 215.195d {+14h 20m 47s} (1950)
GRB_DEC:         -48.233d {-48d 13' 59"} (J2000),
                 -48.289d {-48d 17' 19"} (current),
                 -48.007d {-48d 00' 24"} (1950)
GRB_ERROR:       25.87 [deg radius, statistical plus systematic]
GRB_INTEN:       69 [cnts/sec] 
DATA_SIGNIF:     6.00 [sigma]  
INTEG_TIME:      4.096 [sec]   
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        32872.39 SOD {09:07:52.39} UT
GRB_PHI:         162.00 [deg]  
GRB_THETA:        75.00 [deg]  
DATA_TIME_SCALE: 4.0960 [sec]  
HARD_RATIO:      -0.31
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB     
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 1,0,1, 0,0,
SUN_POSTN:        58.56d {+03h 54m 15s}  +20.30d {+20d 17' 55"}
SUN_DIST:        146.74 [deg]   Sun_angle= -10.5 [hr] (East of Sun)
MOON_POSTN:       63.00d {+04h 11m 59s}  +21.15d {+21d 09' 10"} 
MOON_DIST:       145.42 [deg]  
MOON_ILLUM:      0 [%]
GAL_COORDS:      318.46, 11.83 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      230.61,-31.91 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.
COMMENTS:        This trigger occurred at longitude,latitude = 213.12,-24.88 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 21 May 12 09:09:51 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     359284074
GRB_RA:          192.500d {+12h 50m 00s} (J2000),
                 192.671d {+12h 50m 41s} (current),
                 191.813d {+12h 47m 15s} (1950)
GRB_DEC:         -38.820d {-38d 49' 11"} (J2000),
                 -38.887d {-38d 53' 13"} (current),
                 -38.548d {-38d 32' 51"} (1950)
GRB_ERROR:       11.05 [deg radius, statistical only]
DATA_SIGNIF:     7.00 [sigma]  
DATA_INTERVAL:   4.096 [sec]   
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        32872.39 SOD {09:07:52.39} UT
GRB_PHI:         142.00 [deg]  
GRB_THETA:        75.00 [deg]  
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4143 (Gnd S/W Version number)
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 55"}
SUN_DIST:        136.54 [deg]   Sun_angle= -8.9 [hr] (East of Sun)
MOON_POSTN:       63.01d {+04h 12m 03s}  +21.15d {+21d 09' 14"}
MOON_DIST:       133.62 [deg]  
MOON_ILLUM:      0 [%]
GAL_COORDS:      302.63, 24.05 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      207.98,-30.54 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.
COMMENTS:        This Notice was ground-generated -- not flight-generated.
COMMENTS:
COMMENTS:        NOTE: This GBM event is temporally(4.0<100sec) coincident with the SWIFT_BAT event (trignum=522586).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:09:05 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     522586,   Seg_Num: 0
GRB_RA:          197.014d {+13h 08m 03s} (J2000),
                 197.199d {+13h 08m 48s} (current),
                 196.269d {+13h 05m 05s} (1950)
GRB_DEC:         -52.746d {-52d 44' 45"} (J2000),
                 -52.812d {-52d 48' 42"} (current),
                 -52.479d {-52d 28' 44"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       42398 [cnts]    Image_Peak=530 [image_cnts]
TRIGGER_DUR:     12.160 [sec] 
TRIGGER_INDEX:   491     E_range: 50-350 keV
BKG_INTEN:       206815 [cnts]
BKG_TIME:        32775.76 SOD {09:06:15.76} UT
BKG_DUR:         64 [sec]
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        32868.82 SOD {09:07:48.82} UT
GRB_PHI:         102.07 [deg]
GRB_THETA:        29.97 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     11.61 [sigma]
IMAGE_SIGNIF:    8.56 [sigma]
MERIT_PARAMS:     +1  +0  +0  +4  +3  -1  +0  +0 +70  +0 
SUN_POSTN:        58.56d {+03h 54m 16s}  +20.30d {+20d 17' 55"}
SUN_DIST:        134.57 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.00d {+04h 12m 01s}  +21.15d {+21d 09' 11"}
MOON_DIST:       132.88 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.48, 10.04 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      219.61,-41.29 [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 = 168.63,14.41 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(4.0<100sec) coincident with the FERMI_GBM event (trignum=359284074).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:10:36 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     522586,   Seg_Num: 0
GRB_RA:          197.0093d {+13h 08m 02.23s} (J2000),
                 197.1947d {+13h 08m 46.72s} (current),
                 196.2645d {+13h 05m 03.46s} (1950)
GRB_DEC:         -52.7552d {-52d 45' 18.7"} (J2000),
                 -52.8211d {-52d 49' 15.9"} (current),
                 -52.4884d {-52d 29' 18.4"} (1950)
GRB_ERROR:       5.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.42e-09 [erg/cm2/sec]
GRB_SIGNIF:      6.70 [sigma]
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  32987.66 SOD {09:09:47.66} UT,   118.8 [sec] since BAT Trigger Time
TAM[0-3]:        327.68 237.24 261.36 243.90
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 56"}
SUN_DIST:        134.57 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.02d {+04h 12m 04s}  +21.15d {+21d 09' 16"}
MOON_DIST:       132.87 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.48, 10.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      219.62,-41.30 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.58 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:10:48 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     522586,   Seg_Num: 0
GRB_RA:          197.0093d {+13h 08m 02.2s} (J2000),
                 197.1947d {+13h 08m 46.7s} (current),
                 196.2645d {+13h 05m 03.4s} (1950)
GRB_DEC:         -52.7552d {-52d 45' 18.7"} (J2000),
                 -52.8211d {-52d 49' 15.9"} (current),
                 -52.4884d {-52d 29' 18.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       45 [cnts]
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  32987.66 SOD {09:09:47.66} UT,   118.8 [sec] since BAT Trigger Time
CENTROID_X:      331.34,  raw= 331  [pixels]
CENTROID_Y:      306.31,  raw= 306  [pixels]
ROLL:            240.77 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   19.60
GRB_POS_XRT_Z:   65.16
IMAGE_URL:       sw00522586000msxps_rw.img
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 56"}
SUN_DIST:        134.57 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.02d {+04h 12m 05s}  +21.15d {+21d 09' 16"}
MOON_DIST:       132.86 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.48, 10.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      219.62,-41.30 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:11:18 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     522586,   Seg_Num: 0
GRB_RA:          197.0093d {+13h 08m 02.2s} (J2000),
                 197.1947d {+13h 08m 46.7s} (current),
                 196.2645d {+13h 05m 03.4s} (1950)
GRB_DEC:         -52.7552d {-52d 45' 18.7"} (J2000),
                 -52.8211d {-52d 49' 15.9"} (current),
                 -52.4884d {-52d 29' 18.4"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       45 [cnts]
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  32987.66 SOD {09:09:47.66} UT,   118.8 [sec] since BAT Trigger Time
CENTROID_X:      331.34,  raw= 331  [pixels]
CENTROID_Y:      306.31,  raw= 306  [pixels]
ROLL:            240.77 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   19.60
GRB_POS_XRT_Z:   65.16
IMAGE_URL:       sw00522586000msxps_rw.img
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 56"}
SUN_DIST:        134.57 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.02d {+04h 12m 06s}  +21.15d {+21d 09' 17"}
MOON_DIST:       132.86 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.48, 10.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      219.62,-41.30 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:12:22 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     522586,   Seg_Num: 0
GRB_RA:          197.014d {+13h 08m 03s} (J2000),
                 197.199d {+13h 08m 48s} (current),
                 196.269d {+13h 05m 05s} (1950)
GRB_DEC:         -52.746d {-52d 44' 45"} (J2000),
                 -52.812d {-52d 48' 42"} (current),
                 -52.479d {-52d 28' 44"} (1950)
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        32868.82 SOD {09:07:48.82} UT
TRIGGER_INDEX:   491
GRB_PHI:         102.07 [deg]
GRB_THETA:        29.97 [deg]
DELTA_TIME:      -25.00 [sec]
TRIGGER_DUR:     12.160 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.61 [sigma]
IMAGE_SIGNIF:    8.56 [sigma]
LC_URL:          sw00522586000msb.lc
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 57"}
SUN_DIST:        134.57 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.03d {+04h 12m 08s}  +21.16d {+21d 09' 20"}
MOON_DIST:       132.86 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.48, 10.04 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      219.61,-41.29 [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 = 168.63,14.41 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:13:18 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.979d {+13h 07m 55s} (J2000)
POINT_DEC:       -52.759d {-52d 45' 32"} (J2000)
POINT_ROLL:      240.767d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  32996.21 SOD {09:09:56.21} UT,   127.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.944
N_STARS:         190
X_OFFSET:        312 [pixels]
Y_OFFSET:        648 [pixels]
X_MAX:           1271 [pixels]
Y_MAX:           1607 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00522586000msufc0127.fits
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 57"}
SUN_DIST:        134.55 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.04d {+04h 12m 10s}  +21.16d {+21d 09' 23"}
MOON_DIST:       132.84 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:13:55 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.979d {+13h 07m 55s} (J2000)
POINT_DEC:       -52.759d {-52d 45' 32"} (J2000)
POINT_ROLL:      240.767d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  32996.21 SOD {09:09:56.21} UT,   127.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.944
N_STARS:         190
X_OFFSET:        312 [pixels]
Y_OFFSET:        648 [pixels]
X_MAX:           1271 [pixels]
Y_MAX:           1607 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00522586000msufc0127.fits
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 57"}
SUN_DIST:        134.55 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.05d {+04h 12m 11s}  +21.16d {+21d 09' 24"}
MOON_DIST:       132.83 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [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:     Mon 21 May 12 09:15:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.979d {+13h 07m 55s} (J2000)
POINT_DEC:       -52.759d {-52d 45' 32"} (J2000)
ROLL:            240.767d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  32996.21 SOD {09:09:56.21} UT,   127.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359284204
X_OFFSET:        647 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       807
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00522586000msuni0136.fits
SUN_POSTN:        58.57d {+03h 54m 17s}  +20.30d {+20d 17' 58"}
SUN_DIST:        134.55 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.06d {+04h 12m 14s}  +21.16d {+21d 09' 27"}
MOON_DIST:       132.83 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [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:     Mon 21 May 12 09:14:48 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.979d {+13h 07m 55s} (J2000)
POINT_DEC:       -52.759d {-52d 45' 32"} (J2000)
ROLL:            240.767d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  32996.21 SOD {09:09:56.21} UT,   127.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359284204
X_OFFSET:        647 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       807
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00522586000msuni0136.fits
SUN_POSTN:        58.57d {+03h 54m 16s}  +20.30d {+20d 17' 58"}
SUN_DIST:        134.55 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.05d {+04h 12m 13s}  +21.16d {+21d 09' 27"}
MOON_DIST:       132.83 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [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:     Mon 21 May 12 09:21:03 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 35"} (J2000)
POINT_ROLL:      240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33154.47 SOD {09:12:34.47} UT,   285.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.883
N_STARS:         190
X_OFFSET:        327 [pixels]
Y_OFFSET:        587 [pixels]
X_MAX:           1286 [pixels]
Y_MAX:           1546 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00522586000msufc0285.fits
SUN_POSTN:        58.57d {+03h 54m 18s}  +20.30d {+20d 18' 01"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.11d {+04h 12m 26s}  +21.16d {+21d 09' 43"}
MOON_DIST:       132.80 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:21:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 35"} (J2000)
POINT_ROLL:      240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33154.47 SOD {09:12:34.47} UT,   285.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.883
N_STARS:         190
X_OFFSET:        327 [pixels]
Y_OFFSET:        587 [pixels]
X_MAX:           1286 [pixels]
Y_MAX:           1546 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00522586000msufc0285.fits
SUN_POSTN:        58.57d {+03h 54m 18s}  +20.30d {+20d 18' 01"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.11d {+04h 12m 28s}  +21.16d {+21d 09' 45"}
MOON_DIST:       132.80 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [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:     Mon 21 May 12 09:21:54 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     522586,   Seg_Num: 0
GRB_RA:          197.0099d {+13h 08m 02.37s} (J2000),
                 197.1953d {+13h 08m 46.87s} (current),
                 196.2650d {+13h 05m 03.61s} (1950)
GRB_DEC:         -52.7548d {-52d 45' 17.2"} (J2000),
                 -52.8207d {-52d 49' 14.5"} (current),
                 -52.4880d {-52d 29' 16.9"} (1950)
GRB_ERROR:       2.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33024.00 SOD {09:10:24.00} UT,   155.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        58.57d {+03h 54m 18s}  +20.30d {+20d 18' 01"}
SUN_DIST:        134.56 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.12d {+04h 12m 28s}  +21.16d {+21d 09' 45"}
MOON_DIST:       132.82 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.48, 10.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      219.62,-41.30 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:22:33 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 35"} (J2000)
ROLL:            240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33154.47 SOD {09:12:34.47} UT,   285.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     359284362
X_OFFSET:        647 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       807
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00522586000msuni0294.fits
SUN_POSTN:        58.57d {+03h 54m 18s}  +20.30d {+20d 18' 02"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.12d {+04h 12m 29s}  +21.16d {+21d 09' 47"}
MOON_DIST:       132.79 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [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:     Mon 21 May 12 09:22:47 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 35"} (J2000)
ROLL:            240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33154.47 SOD {09:12:34.47} UT,   285.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     359284362
X_OFFSET:        647 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       807
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00522586000msuni0294.fits
SUN_POSTN:        58.57d {+03h 54m 18s}  +20.30d {+20d 18' 02"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.12d {+04h 12m 30s}  +21.16d {+21d 09' 48"}
MOON_DIST:       132.79 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [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 #13305
J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC), M. M. Chester (PSU), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), B. Gendre (ASDC), D. M. Palmer (LANL), E. Sonbas (NASA/GSFC/Adiyaman Univ.) and G. Stratta (ASDC) report on behalf of the Swift Team:
At 09:07:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120521B (trigger=522586). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 197.014, -52.746 which is
```
   RA(J2000)  =  13h 08m 03s
   Dec(J2000) = -52d 44' 45"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple overlapping peaks with a duration of about 40 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~6 sec after the trigger.
The XRT began observing the field at 09:09:47.6 UT, 118.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 197.0100, -52.7548 which is equivalent to:
```
   RA(J2000)  = 13h 08m 02.41s
   Dec(J2000) = -52d 45' 17.4"
```
with an uncertainty of 2.5 arcseconds (radius, 90% containment). This location is 32 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.27 x 10^21 cm^-2, Kalberla et al. 2005), with an excess column of 2.2 (+1.94/-1.36) x 10^22 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 1.42e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 127 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 0.45.
Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:29:09 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 34"} (J2000)
POINT_ROLL:      240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33734.37 SOD {09:22:14.37} UT,   865.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.769
N_STARS:         190
X_OFFSET:        87 [pixels]
Y_OFFSET:        347 [pixels]
X_MAX:           1526 [pixels]
Y_MAX:           1786 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00522586000msufc0865.fits
SUN_POSTN:        58.58d {+03h 54m 19s}  +20.30d {+20d 18' 05"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.18d {+04h 12m 44s}  +21.17d {+21d 10' 05"}
MOON_DIST:       132.77 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:29:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 34"} (J2000)
POINT_ROLL:      240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33734.37 SOD {09:22:14.37} UT,   865.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.769
N_STARS:         190
X_OFFSET:        87 [pixels]
Y_OFFSET:        347 [pixels]
X_MAX:           1526 [pixels]
Y_MAX:           1786 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00522586000msufc0865.fits
SUN_POSTN:        58.58d {+03h 54m 19s}  +20.30d {+20d 18' 05"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.19d {+04h 12m 45s}  +21.17d {+21d 10' 06"}
MOON_DIST:       132.76 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [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:     Mon 21 May 12 09:30:44 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 34"} (J2000)
ROLL:            240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33734.37 SOD {09:22:14.37} UT,   865.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359284942
X_OFFSET:        646 [pixels]
Y_OFFSET:        906 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       806
Y_GRB_POS:       1066
BINNING_INDEX:   1
IM_URL:          sw00522586000msuni0874.fits
SUN_POSTN:        58.58d {+03h 54m 19s}  +20.30d {+20d 18' 06"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.20d {+04h 12m 47s}  +21.17d {+21d 10' 09"}
MOON_DIST:       132.76 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 09:31:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     522586,   Seg_Num: 0
POINT_RA:        196.976d {+13h 07m 54s} (J2000)
POINT_DEC:       -52.760d {-52d 45' 34"} (J2000)
ROLL:            240.770d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  33734.37 SOD {09:22:14.37} UT,   865.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359284942
X_OFFSET:        646 [pixels]
Y_OFFSET:        906 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       806
Y_GRB_POS:       1066
BINNING_INDEX:   1
IM_URL:          sw00522586000msuni0874.fits
SUN_POSTN:        58.58d {+03h 54m 19s}  +20.30d {+20d 18' 06"}
SUN_DIST:        134.54 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       63.20d {+04h 12m 48s}  +21.17d {+21d 10' 10"}
MOON_DIST:       132.76 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      305.46, 10.03 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      219.60,-41.31 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #13306
Gendre B. (ASDC/INAF-OAR), Klotz A. (IRAP-CNRS-OMP), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 120521B detected by SWIFT (trigger 522586) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile.
The observations started 88.8s after the GRB trigger (25.6s after the notice). The elevation of the field decreased from 12 degrees above horizon and weather conditions were poor.
In a clean exposure, taken between T0 + 473.1s and T0 + 563.1s, we do not detect any afterglow with a limiting magnitude of R > 17.2.
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=305.4846 lat=+10.0434 and the galactic extinction in R band is 1.2 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S.
This message may be cited.
GCN Circular #13307
D Bersier, C. Guidorzi, A. Melandri, J. Jalpelj report:
The Faulkes Telescope South robotically observed GRB120521A (Swift trigger 522586, Cumming et al, GCN 13305). The first exposure started approximately 240 seconds after the trigger time. Digital image subtraction does not reveal any variable source inside the XRT error circle. We find upper limits in R ~ 22.0 (40 minutes after the burst).
GCN Circular #13308
D. Bersier wishes to apologise for any confusion related to the wrong title of GCN 13307. The GCN Circular reports observations of GRB120521B, not GRB120521A. The title should read: "GRB120521B: Faulkes Telescope South observations".
I thank C. Guidorzi for drawing my attention to this mistake.
GCN Circular #13309
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, D.Denisenko, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, A.Kuznetsov Moscow Lomonosov State University, Sternberg Astronomical Institute,
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
V.Krushinski, I.Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University
MASTER VWF robotic cameras (400 square degrees, 1 pix = 22 arcsec, http://observ.pereplet.ru) located in Argentina (Observatorio Astronomico Felix Aguilar) was pointed to the Fermi Trigger 359284074 12 sec before Swift notice time and 65 sec after Swift trigger (Cummings et al., GCN Circ 13305) time at 2012-05-21 09:08:53 UT.
On our first image (5 sec exposure) we have not found any OT.
```
T_start(UT)  T - T_trig  MeanTime     Exp   Limit  Coadd?   Filter
----------------------------------------------------------------------
09 08 53       65 s       67.5s        5s    11.5    No     Unfiltered
09 08 53       65 s       77.5s       25s    12.4    Yes    Unfiltered
```
The message may be cited.
GCN Circular #13311
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 809 s of XRT Photon Counting mode data and 1 UVOT images for GRB 120521B, 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 = 197.00990, -52.75479 which is equivalent to:
```
RA (J2000): 13h 08m 2.38s
Dec (J2000): -52d 45' 17.2"
```
with an uncertainty of 2.0 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 #13316
P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), J.A. Kennea (PSU), M.C. Stroh (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA) and J.R. Cummings report on behalf of the Swift-XRT team:
We have analysed 9.1 ks of XRT data for GRB 120521B (Cummings et al. GCN Circ. 13305), from 125 s to 19.4 ks after the BAT trigger. The data comprise 28 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 13311).
The light curve can be modelled with an initial power-law decay with an index of alpha=5.0 (+0.7, -0.6), followed by a break at T+267 s to an alpha of 0.69 (+/-0.07).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.9 (+0.4, -0.3). The best-fitting absorption column is 1.5 (+0.4, -0.3) x 10^22 cm^-2, in excess of the Galactic value of 2.3 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 6.6 x 10^-11 (1.4 x 10^-10) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.5 (+0.4, -0.3) x 10^22 cm^-2
Galactic foreground: 2.3 x 10^21 cm^-2
Excess significance: 6.2 sigma
Photon index:	     1.9 (+0.4, -0.3)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00522586.
This circular is an official product of the Swift-XRT team.
GCN Circular #13317
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120521B (trigger #522586) (Cummngs, et al., GCN Circ. 13305). The BAT ground-calculated position is RA, Dec = 197.016, -52.742 deg, which is
```
   RA(J2000)  =  13h 08m 03.9s 
   Dec(J2000) = -52d 44' 31.9" 
```
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%.
The mask-weighted light curve shows several overlapping peaks starting at ~T-1 sec, with equal-amplitude maximum peaks at ~T+6 and ~T+32 sec, and ending at around T+180 sec. There is a possibility (at the 2-sigma level) that emission continues out past the T+243sec end of the downlinked data. T90 (15-350 keV) is 31.4 +- 4.0 sec (estimated error including systematics).
The time-averaged spectrum from T-1.39 to T+35.58 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.97 +- 0.15. The fluence in the 15-150 keV band is 1.5 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+31.04 sec in the 15-150 keV band is 0.9 +- 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/522586/BA/
GCN Circular #13328
A. Rossi (TLS Tautenburg), M. Nardini (Universita'degli Studi Milano-Bicocca), S. Klose (TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 120521B (Swift trigger 522586; Cummings et al., GCN 13305) simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile).
Observations started at 00:35 UT on 2012-05-22, 15.3 h after the GRB trigger, and lasted for 140 minutes. They were performed with good sky conditions at an average seeing of 0.8" and at an average airmass of 1.05. (At the time of the GRB trigger the field was already too close to the telescope's horizon distance limit in order to observe it with GROND.)
Based on an exposure of 37 minutes in the optical and 30 minutes in the NIR we do not detect any source within the Swift-XRT error circle reported by Osborne et al. (GCN 13311). Preliminary observed upper limits (AB mags) are:
```
  g' > 24.5
  r' > 24.2
  i' > 23.9
  z' > 23.9
  J  > 21.3
  H  > 20.3
  Ks > 19.3.
```
These limits are derived based on GROND zeropoints (g'r'i'z') and 2MASS stars (JHK). We note that the Galactic reddening along the line of sight is E_(B-V)= 0.45 mag (Schlegel et al. 1998).
GCN Circular #13330
S. R. Oates (MSSL-UCL) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120521B 127 s after the BAT trigger (Cummings et al., GCN Circ. 13305). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 13311) 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           127          277          147         >19.4
u_FC               286          535          246         >19.4
white              127        30912         2930         >19.8
v                  615        23584         2045         >18.7
b                  541        36686         2819         >19.7
u                  286        36128         2526         >20.2
w1                 665        35215         2046         >20.7
m2                5582        24489         1279         >21.0
w2                 765        19363         1746         >21.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.45 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #13339
David Gruber (MPE) reports on behalf of the Fermi GBM Team:
"At 09:07:52.39 UT on 21 May 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 120521B (trigger 359284074 / 120521380). which was also detected by the Swift/BAT (Krimm et al. 2012, GCN 13317) The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 84 degrees.
The GBM light curve consists of a single pulse with a duration (T90) of about 91 s (50-300 keV). The time-averaged spectrum from T0-5 s to T0+29 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.34 +/- 0.20 and the cutoff energy, parameterized as Epeak, is 213 +/- 29 keV
The event fluence (10-1000 keV) over the T90 time interval is (3.11 +/- 0.07)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.4 s in the 10-1000 keV band is 1.55 +/- 0.23 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #13342
S. Rapoport, S. Sweet, J. Scharwachter, B. Schmidt, M. Childress
report observations of GRB120521B taken on 2012-05-21.42 UTC (2.7 hours post-alert) using the Wide Field Spectrograph (WiFeS) on the ANU 2.3m, obtaining 3x900s integration at resolution R=3000.
Spectral summation of the sky-subtracted data cube in a 3" radius centered at the GRB location shows no detectable optical counterpart to the GRB and no detectable host galaxy. Based on measurement of a nearby field star in the data cube (m_B=18.4, m_R=17.2 -- USNO) we estimate a non-detection upper limit of m_R=20.5 and m_B=20.0 at 5 sigma for the GRB or its host galaxy.

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Jochen Greiner, last update: 24-May-2012 [Disclaimer]