Gamma-ray Burst 110521A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 15:52:25 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     453788,   Seg_Num: 0
GRB_RA:          120.144d {+08h 00m 35s} (J2000),
                 120.346d {+08h 01m 23s} (current),
                 119.254d {+07h 57m 01s} (1950)
GRB_DEC:         +45.798d {+45d 47' 53"} (J2000),
                 +45.766d {+45d 45' 58"} (current),
                 +45.936d {+45d 56' 09"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       25464 [cnts]    Image_Peak=461 [image_cnts]
TRIGGER_DUR:     8.192 [sec] 
TRIGGER_INDEX:   490     E_range: 50-350 keV
BKG_INTEN:       174509 [cnts]
BKG_TIME:        57001.02 SOD {15:50:01.02} UT
BKG_DUR:         64 [sec]
GRB_DATE:        15702 TJD;   141 DOY;   11/05/21
GRB_TIME:        57091.45 SOD {15:51:31.45} UT
GRB_PHI:         -144.20 [deg]
GRB_THETA:        13.81 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     17.88 [sigma]
IMAGE_SIGNIF:    7.26 [sigma]
MERIT_PARAMS:     +1  +0  +0  +3  +3  -3  +0  +0 -55  +0 
SUN_POSTN:        58.09d {+03h 52m 20s}  +20.20d {+20d 12' 10"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.77d {+19h 43m 04s}  -18.61d {-18d 36' 27"}
MOON_DIST:       152.58 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.70, 30.75 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      112.67, 24.70 [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 = 359.25,19.46 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 15:53:48 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     453788,   Seg_Num: 0
GRB_RA:          120.1347d {+08h 00m 32.32s} (J2000),
                 120.3369d {+08h 01m 20.85s} (current),
                 119.2446d {+07h 56m 58.71s} (1950)
GRB_DEC:         +45.8273d {+45d 49' 38.2"} (J2000),
                 +45.7954d {+45d 47' 43.3"} (current),
                 +45.9652d {+45d 57' 54.7"} (1950)
GRB_ERROR:       5.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       8.07e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.56 [sigma]
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57189.97 SOD {15:53:09.97} UT,   98.5 [sec] since BAT Trigger Time
TAM[0-3]:        327.63 237.22 261.55 243.42
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 10"}
SUN_DIST:         56.48 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.78d {+19h 43m 07s}  -18.60d {-18d 36' 15"}
MOON_DIST:       152.55 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.66, 30.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      112.65, 24.73 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.79 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 15:53:57 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     453788,   Seg_Num: 0
GRB_RA:          120.1347d {+08h 00m 32.3s} (J2000),
                 120.3369d {+08h 01m 20.8s} (current),
                 119.2446d {+07h 56m 58.7s} (1950)
GRB_DEC:         +45.8273d {+45d 49' 38.2"} (J2000),
                 +45.7954d {+45d 47' 43.3"} (current),
                 +45.9652d {+45d 57' 54.7"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       31 [cnts]
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57189.97 SOD {15:53:09.97} UT,   98.5 [sec] since BAT Trigger Time
CENTROID_X:      284.37,  raw= 284  [pixels]
CENTROID_Y:      255.05,  raw= 255  [pixels]
ROLL:            264.89 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -101.23
GRB_POS_XRT_Z:   -42.25
IMAGE_URL:       sw00453788000msxps_rw.img
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 10"}
SUN_DIST:         56.48 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.78d {+19h 43m 08s}  -18.60d {-18d 36' 14"}
MOON_DIST:       152.55 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.66, 30.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      112.65, 24.73 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 15:54:03 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     453788,   Seg_Num: 0
GRB_RA:          120.1347d {+08h 00m 32.3s} (J2000),
                 120.3369d {+08h 01m 20.8s} (current),
                 119.2446d {+07h 56m 58.7s} (1950)
GRB_DEC:         +45.8273d {+45d 49' 38.2"} (J2000),
                 +45.7954d {+45d 47' 43.3"} (current),
                 +45.9652d {+45d 57' 54.7"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       31 [cnts]
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57189.97 SOD {15:53:09.97} UT,   98.5 [sec] since BAT Trigger Time
CENTROID_X:      284.37,  raw= 284  [pixels]
CENTROID_Y:      255.05,  raw= 255  [pixels]
ROLL:            264.89 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -101.23
GRB_POS_XRT_Z:   -42.25
IMAGE_URL:       sw00453788000msxps_rw.img
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 10"}
SUN_DIST:         56.48 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.78d {+19h 43m 08s}  -18.60d {-18d 36' 13"}
MOON_DIST:       152.55 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.66, 30.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      112.65, 24.73 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 15:55:14 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     453788,   Seg_Num: 0
GRB_RA:          120.144d {+08h 00m 35s} (J2000),
                 120.346d {+08h 01m 23s} (current),
                 119.254d {+07h 57m 01s} (1950)
GRB_DEC:         +45.798d {+45d 47' 53"} (J2000),
                 +45.766d {+45d 45' 58"} (current),
                 +45.936d {+45d 56' 09"} (1950)
GRB_DATE:        15702 TJD;   141 DOY;   11/05/21
GRB_TIME:        57091.45 SOD {15:51:31.45} UT
TRIGGER_INDEX:   490
GRB_PHI:         -144.20 [deg]
GRB_THETA:        13.81 [deg]
DELTA_TIME:      77.00 [sec]
TRIGGER_DUR:     8.192 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     17.88 [sigma]
IMAGE_SIGNIF:    7.26 [sigma]
LC_URL:          sw00453788000msb.lc
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 11"}
SUN_DIST:         56.48 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.79d {+19h 43m 11s}  -18.60d {-18d 36' 04"}
MOON_DIST:       152.57 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.70, 30.75 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      112.67, 24.70 [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 = 359.25,19.46 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 15:56:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.155d {+08h 00m 37s} (J2000)
POINT_DEC:       +45.800d {+45d 48' 02"} (J2000)
POINT_ROLL:      264.890d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57196.43 SOD {15:53:16.43} UT,   105.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.899
N_STARS:         39
X_OFFSET:        528 [pixels]
Y_OFFSET:        488 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1447 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00453788000msufc0104.fits
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 11"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.80d {+19h 43m 13s}  -18.60d {-18d 35' 55"}
MOON_DIST:       152.57 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.70, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 15:56:54 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.155d {+08h 00m 37s} (J2000)
POINT_DEC:       +45.800d {+45d 48' 02"} (J2000)
POINT_ROLL:      264.890d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57196.43 SOD {15:53:16.43} UT,   105.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.899
N_STARS:         39
X_OFFSET:        528 [pixels]
Y_OFFSET:        488 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1447 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00453788000msufc0104.fits
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 12"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.81d {+19h 43m 14s}  -18.60d {-18d 35' 50"}
MOON_DIST:       152.57 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.70, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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:     Sat 21 May 11 15:57:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.155d {+08h 00m 37s} (J2000)
POINT_DEC:       +45.800d {+45d 48' 02"} (J2000)
ROLL:            264.890d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57196.43 SOD {15:53:16.43} UT,   105.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327686003
X_OFFSET:        975 [pixels]
Y_OFFSET:        982 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1135
Y_GRB_POS:       1142
BINNING_INDEX:   1
IM_URL:          sw00453788000msuni0111.fits
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 12"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.82d {+19h 43m 16s}  -18.60d {-18d 35' 43"}
MOON_DIST:       152.57 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.70, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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:     Sat 21 May 11 15:58:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.155d {+08h 00m 37s} (J2000)
POINT_DEC:       +45.800d {+45d 48' 02"} (J2000)
ROLL:            264.890d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57196.43 SOD {15:53:16.43} UT,   105.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327686003
X_OFFSET:        975 [pixels]
Y_OFFSET:        982 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1135
Y_GRB_POS:       1142
BINNING_INDEX:   1
IM_URL:          sw00453788000msuni0111.fits
SUN_POSTN:        58.09d {+03h 52m 21s}  +20.20d {+20d 12' 12"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.82d {+19h 43m 17s}  -18.59d {-18d 35' 41"}
MOON_DIST:       152.57 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.70, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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:     Sat 21 May 11 16:03:28 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
POINT_ROLL:      264.894d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57354.90 SOD {15:55:54.90} UT,   263.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.176
N_STARS:         22
X_OFFSET:        655 [pixels]
Y_OFFSET:        662 [pixels]
X_MAX:           1614 [pixels]
Y_MAX:           1621 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00453788000msufc0263.fits
SUN_POSTN:        58.09d {+03h 52m 22s}  +20.20d {+20d 12' 15"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.87d {+19h 43m 29s}  -18.58d {-18d 34' 57"}
MOON_DIST:       152.56 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 16:03:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
POINT_ROLL:      264.894d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57354.90 SOD {15:55:54.90} UT,   263.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.176
N_STARS:         22
X_OFFSET:        655 [pixels]
Y_OFFSET:        662 [pixels]
X_MAX:           1614 [pixels]
Y_MAX:           1621 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00453788000msufc0263.fits
SUN_POSTN:        58.09d {+03h 52m 22s}  +20.20d {+20d 12' 15"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.87d {+19h 43m 29s}  -18.58d {-18d 34' 54"}
MOON_DIST:       152.56 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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:     Sat 21 May 11 16:03:55 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     453788,   Seg_Num: 0
GRB_RA:          120.1326d {+08h 00m 31.82s} (J2000),
                 120.3348d {+08h 01m 20.35s} (current),
                 119.2425d {+07h 56m 58.21s} (1950)
GRB_DEC:         +45.8263d {+45d 49' 34.6"} (J2000),
                 +45.7944d {+45d 47' 39.7"} (current),
                 +45.9642d {+45d 57' 51.0"} (1950)
GRB_ERROR:       2.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57228.00 SOD {15:53:48.00} UT,   136.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        58.09d {+03h 52m 22s}  +20.20d {+20d 12' 15"}
SUN_DIST:         56.47 [deg]   Sun_angle= -4.1 [hr] (East of Sun)
MOON_POSTN:      295.87d {+19h 43m 30s}  -18.58d {-18d 34' 53"}
MOON_DIST:       152.54 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.67, 30.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      112.65, 24.73 [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:     Sat 21 May 11 16:04:54 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
ROLL:            264.894d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57354.90 SOD {15:55:54.90} UT,   263.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     327686161
X_OFFSET:        975 [pixels]
Y_OFFSET:        982 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1135
Y_GRB_POS:       1142
BINNING_INDEX:   1
IM_URL:          sw00453788000msuni0270.fits
SUN_POSTN:        58.09d {+03h 52m 23s}  +20.20d {+20d 12' 16"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.88d {+19h 43m 32s}  -18.58d {-18d 34' 45"}
MOON_DIST:       152.56 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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:     Sat 21 May 11 16:05:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
ROLL:            264.894d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57354.90 SOD {15:55:54.90} UT,   263.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     327686161
X_OFFSET:        975 [pixels]
Y_OFFSET:        982 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1135
Y_GRB_POS:       1142
BINNING_INDEX:   1
IM_URL:          sw00453788000msuni0270.fits
SUN_POSTN:        58.09d {+03h 52m 23s}  +20.20d {+20d 12' 16"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.89d {+19h 43m 33s}  -18.58d {-18d 34' 42"}
MOON_DIST:       152.56 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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 #12031
S. R. Oates (UCL-MSSL), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), C. B. Markwardt (NASA/GSFC), A. Melandri (INAF-OAB), P. T. O\'Brien (U Leicester), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL) and E. Sonbas (GSFC/USRA/Adiyaman Univ.) report on behalf of the Swift Team:
At 15:51:31.45 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110521A (trigger=453788). Swift slewed immediately to this burst. The BAT on-board calculated location is RA, Dec 120.144, +45.798, which is
```
   RA(J2000)  =  08h 00m 35s
   Dec(J2000) = +45d 47' 53"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a few pulses with a total duration of about 20 sec. The peak count rate was ~1800 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the field at 15:53:10.0 UT, 98.5 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 120.1327, 45.8264 which is equivalent to:
```
   RA(J2000)  = 08h 00m 31.84s
   Dec(J2000) = +45d 49' 35.1"
```
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 106 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 (4.51 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 5.5 (+2.93/-2.35) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 8.07e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 104 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 0.09.
Burst Advocate for this burst is S. R. Oates (sro AT mssl.ucl.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 16:08:53 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
POINT_ROLL:      264.893d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57958.59 SOD {16:05:58.59} UT,   867.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.881
N_STARS:         135
X_OFFSET:        415 [pixels]
Y_OFFSET:        422 [pixels]
X_MAX:           1854 [pixels]
Y_MAX:           1861 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00453788000msufc0867.fits
SUN_POSTN:        58.10d {+03h 52m 23s}  +20.20d {+20d 12' 18"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.92d {+19h 43m 41s}  -18.57d {-18d 34' 13"}
MOON_DIST:       152.55 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 11 16:09:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
POINT_ROLL:      264.893d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57958.59 SOD {16:05:58.59} UT,   867.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.881
N_STARS:         135
X_OFFSET:        415 [pixels]
Y_OFFSET:        422 [pixels]
X_MAX:           1854 [pixels]
Y_MAX:           1861 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00453788000msufc0867.fits
SUN_POSTN:        58.10d {+03h 52m 23s}  +20.21d {+20d 12' 18"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.92d {+19h 43m 42s}  -18.57d {-18d 34' 08"}
MOON_DIST:       152.55 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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:     Sat 21 May 11 16:10:24 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
ROLL:            264.893d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57958.59 SOD {16:05:58.59} UT,   867.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327686765
X_OFFSET:        974 [pixels]
Y_OFFSET:        981 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1134
Y_GRB_POS:       1141
BINNING_INDEX:   1
IM_URL:          sw00453788000msuni0874.fits
SUN_POSTN:        58.10d {+03h 52m 23s}  +20.21d {+20d 12' 19"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.93d {+19h 43m 44s}  -18.57d {-18d 34' 00"}
MOON_DIST:       152.55 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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:     Sat 21 May 11 16:10:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     453788,   Seg_Num: 0
POINT_RA:        120.159d {+08h 00m 38s} (J2000)
POINT_DEC:       +45.804d {+45d 48' 13"} (J2000)
ROLL:            264.893d
IMG_START_DATE:  15702 TJD;   141 DOY;   11/05/21
IMG_START_TIME:  57958.59 SOD {16:05:58.59} UT,   867.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327686765
X_OFFSET:        974 [pixels]
Y_OFFSET:        981 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1134
Y_GRB_POS:       1141
BINNING_INDEX:   1
IM_URL:          sw00453788000msuni0874.fits
SUN_POSTN:        58.10d {+03h 52m 23s}  +20.21d {+20d 12' 19"}
SUN_DIST:         56.49 [deg]   Sun_angle= -4.2 [hr] (East of Sun)
MOON_POSTN:      295.94d {+19h 43m 45s}  -18.57d {-18d 33' 58"}
MOON_DIST:       152.55 [deg]
MOON_ILLUM:      79 [%]
GAL_COORDS:      173.69, 30.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      112.68, 24.71 [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 #12033
O. Gres, K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Chuvalaev Irkutsk State University
V.Krushinski, I.Zalozhnich, A. Popov Ural State University, Kourovka
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M.Kornilov, A.Sankovich Sternberg Astronomical Institute, Moscow State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov,V. Senik Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka(Siberia) was pointed to the GRB110521A (Oates et al., GCN Circ 12031) 32 sec s after notice time and 92 sec after GRB time at 2011-05-21 15:53:03.316 UT. On our first (20s exposure) set we haven`t found optical transient within SWIFT error-box . The 3-sigma upper limit has been about 16.0 mag
The Swift erros box was inside FOV of the one of the 2 Very Wide Field Cameras (2x480 square degrees, 2x12 Mpixs). We have images before, during and after GRB . The 3-sigma upper limit has been about 12.0 mag each image (5 s exposition). The data reduction is continued.
This message may be cited.
GCN Circular #12034
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 428 s of XRT Photon Counting mode data and 1 UVOT images for GRB 110521A, 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 = 120.13290, +45.82658 which is equivalent to:
```
RA (J2000): 08h 00m 31.90s
Dec (J2000): +45d 49' 35.7"
```
with an uncertainty of 1.9 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #12035
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), S. R. Oates (UCL-MSSL), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+529 sec from recent telemetry downlinks, we report further analysis of BAT GRB 110521A (trigger #453788) (Oates, et al., GCN Circ. 12031). The BAT ground-calculated position is RA, Dec = 120.132, 45.818 deg, which is
```
   RA(J2000)  =  08h 00m 31.7s 
   Dec(J2000) = +45d 49' 05.3" 
```
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shows several overlapping peaks starting at ~T_zero, with the maximum peak at ~T+8 sec, and ending at ~T+18 sec. There is a low significance tail out to around T+60 sec. T90 (15-350 keV) is 13.8 +- 3.3 sec (estimated error including systematics).
The time-averaged spectrum from T+0.2 to T+18.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.90 +- 0.22. The fluence in the 15-150 keV band is 4.4 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+7.88 sec in the 15-150 keV band is 0.5 +- 0.1 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/453788/BA/
GCN Circular #12036
S. Schulze (U. Iceland), D. Xu (WIS), P. Jakobsson (U. Iceland), T. Pursimo (NOT Observatory), report on behalf of a larger collaboration:
We observed the field of GRB 110521A (Oates et al., GCN 12031) with the Nordic Opitcal Telescope (NOT) equipped with ALFOSC. We obtained 3x300 s R-band and 6x300 s I-band images. Observations started at 22:01 UT on May 21 (i.e., 6.1604 hrs after the burst).
We do not detect any source in the stacked R-band and I-band images at the refined XRT position (Beardmore et al., GCN 12034).
The limiting magnitudes are R ~ 24.4 mag at the mid-exposure time t = 6.285 hrs post-burst, and I ~ 23.8 mag at the mid-exposure time t = 6.745 hrs post-burst, calibrated with the #1358-0196725 star (R1 = 19.57, R2 = 19.58, and I =18.81) in the USNO B1 catalogue.
GCN Circular #12038
O. M. Littlejohns (U. Leicester) and S. R. Oates (UCL-MSSL) reports on behalf of the Swift-XRT team:
We have analysed 21 ks of XRT data for GRB 110521A (Oates et al. GCN Circ. 12031), from 87 s to 47.7 ks after the BAT trigger. The data comprise 61 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 12034).
The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=1.5 (+0.4, -0.3). At T+299 s the decay steepens to an alpha of 7.1 (+2.9, -1.3) before breaking again at T+529 s to a final decay with index alpha=1.0 (+0.5, -1.9).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+0.3, -0.6). The best-fitting absorption column is 4.3 (+1.5, -2.6) x 10^21 cm^-2, in excess of the Galactic value of 4.5 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.7 x 10^-11 (7.9 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     4.3 (+1.5, -2.6) x 10^21 cm^-2
Galactic foreground: 4.5 x 10^20 cm^-2
Excess significance: 2.7 sigma
Photon index:	     2.0 (+0.3, -0.6)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00453788.
This circular is an official product of the Swift-XRT team.

GCN Circular #12039
S. R. Oates (MSSL-UCL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 110521A 105 s after the BAT trigger (Oates et al., GCN Circ. 12031). No optical afterglow consistent with the XRT position (Beardmore et al., GCN Circ. 12034) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
---------------------------------------------------------------
white_FC           105          255          147         >20.4
u_FC               263          513          246         >20.0
white              105         6615          766         >21.0
v                  594        41254         2261         >20.5
b                  519        30377         1766         >21.1
u                  263        36155         3624         >21.7
w1                 644        35466         3860         >22.0
m2                 618        41934         3564         >22.3
w2                 570        40340         2262         >22.3
--------------------------------------------------------------

The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.09 in the direction of the burst (Schlegel et al. 1998).

GCN Circular #12040
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M.Kornilov, A.Sankovich Sternberg Astronomical Institute, Moscow State University
O. Gres, K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Chuvalaev Irkutsk State University
V.Krushinski, I.Zalozhnich, A. Popov Ural State University, Kourovka
A. Tlatov, A.V. Parhomenko, D. Dormidontov,V. Senik Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk
The Swift erros box has casually appeared inside FOV of the one of the 2 Very Wide Field Cameras (Gres et al., GCN Circ 12033). We have images before, during and after GRB . The 3-sigma upper limit has been about 12.0 mag (unfiltered, close to V) each image (5 s exposition). The upper limit of coadded images during 15 sec GRB is 12.7. The corresponding optical fluence less than 10^-9 erg/cm^2 The best-fitting absorption column is 4.3 (+1.5, -2.6) x 10^21 cm^-2, in excess of the Galactic value of 4.5 x 10^20 cm^-2 (Littlejohns et al., GCN Circ 12038). The fluence in the 15-150 keV band is 4.4 +- 0.5 x 10^-7 erg/cm2 (Barthelmy et al., GCN Circ 12035). So including ~2 mag absorption:
Fluence_opt/Fluemce_gamma(15-150) < ~1/60
The video is available at http://observ.pereplet.ru/images/GRB110521A/grb110521A.gif .
This message may be cited.
GCN Report 333.1
GCN_Report 333.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_333_1.pdf by S. Oates at MSSL-UCL titled: "Final Report on Swift GRB 110521A"

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Jochen Greiner, last update: 23-May-2011 [Disclaimer]