Gamma-ray Burst 120521C

(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:     Mon 21 May 12 23:33:03 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     522656,   Seg_Num: 0
GRB_RA:          214.290d {+14h 17m 09s} (J2000),
                 214.413d {+14h 17m 39s} (current),
                 213.790d {+14h 15m 10s} (1950)
GRB_DEC:         +42.123d {+42d 07' 23"} (J2000),
                 +42.066d {+42d 03' 58"} (current),
                 +42.354d {+42d 21' 13"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5277 [cnts]    Image_Peak=384 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       26912 [cnts]
BKG_TIME:        84111.76 SOD {23:21:51.76} UT
BKG_DUR:         8 [sec]
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        84127.70 SOD {23:22:07.70} UT
GRB_PHI:          95.50 [deg]
GRB_THETA:        19.17 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     29.41 [sigma]
IMAGE_SIGNIF:    13.33 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +2  +0  +0 +39  +0 
SUN_POSTN:        59.17d {+03h 56m 40s}  +20.42d {+20d 25' 02"}
SUN_DIST:        113.46 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.68d {+04h 42m 43s}  +21.62d {+21d 37' 03"}
MOON_DIST:       108.04 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.08, 66.97 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      190.77, 51.41 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 258.35,20.49 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:33:45 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     522656,   Seg_Num: 0
GRB_RA:          214.2860d {+14h 17m 08.64s} (J2000),
                 214.4095d {+14h 17m 38.28s} (current),
                 213.7871d {+14h 15m 08.89s} (1950)
GRB_DEC:         +42.1438d {+42d 08' 37.6"} (J2000),
                 +42.0869d {+42d 05' 12.6"} (current),
                 +42.3745d {+42d 22' 28.2"} (1950)
GRB_ERROR:       5.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       7.43e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.47 [sigma]
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84196.81 SOD {23:23:16.81} UT,   69.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.22 261.56 243.32
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        59.17d {+03h 56m 40s}  +20.42d {+20d 25' 02"}
SUN_DIST:        113.44 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.69d {+04h 42m 45s}  +21.62d {+21d 37' 04"}
MOON_DIST:       108.02 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.13, 66.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      190.75, 51.42 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.25 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:34:00 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     522656,   Seg_Num: 0
GRB_RA:          214.2860d {+14h 17m 08.6s} (J2000),
                 214.4095d {+14h 17m 38.2s} (current),
                 213.7871d {+14h 15m 08.8s} (1950)
GRB_DEC:         +42.1438d {+42d 08' 37.6"} (J2000),
                 +42.0869d {+42d 05' 12.6"} (current),
                 +42.3745d {+42d 22' 28.2"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       30 [cnts]
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84196.81 SOD {23:23:16.81} UT,   69.1 [sec] since BAT Trigger Time
CENTROID_X:      306.69,  raw= 307  [pixels]
CENTROID_Y:      289.23,  raw= 289  [pixels]
ROLL:            334.57 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -20.66
GRB_POS_XRT_Z:   7.05
IMAGE_URL:       sw00522656000msxps_rw.img
SUN_POSTN:        59.17d {+03h 56m 40s}  +20.42d {+20d 25' 03"}
SUN_DIST:        113.44 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.69d {+04h 42m 45s}  +21.62d {+21d 37' 04"}
MOON_DIST:       108.01 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.13, 66.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      190.75, 51.42 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:33:54 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     522656,   Seg_Num: 0
GRB_RA:          214.2860d {+14h 17m 08.6s} (J2000),
                 214.4095d {+14h 17m 38.2s} (current),
                 213.7871d {+14h 15m 08.8s} (1950)
GRB_DEC:         +42.1438d {+42d 08' 37.6"} (J2000),
                 +42.0869d {+42d 05' 12.6"} (current),
                 +42.3745d {+42d 22' 28.2"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       30 [cnts]
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84196.81 SOD {23:23:16.81} UT,   69.1 [sec] since BAT Trigger Time
CENTROID_X:      306.69,  raw= 307  [pixels]
CENTROID_Y:      289.23,  raw= 289  [pixels]
ROLL:            334.57 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -20.66
GRB_POS_XRT_Z:   7.05
IMAGE_URL:       sw00522656000msxps_rw.img
SUN_POSTN:        59.17d {+03h 56m 40s}  +20.42d {+20d 25' 03"}
SUN_DIST:        113.44 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.69d {+04h 42m 45s}  +21.62d {+21d 37' 04"}
MOON_DIST:       108.01 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.13, 66.96 [deg] galactic lon,lat of the burst
ECL_COORDS:      190.75, 51.42 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:34:42 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     522656,   Seg_Num: 0
GRB_RA:          214.290d {+14h 17m 09s} (J2000),
                 214.413d {+14h 17m 39s} (current),
                 213.790d {+14h 15m 10s} (1950)
GRB_DEC:         +42.123d {+42d 07' 23"} (J2000),
                 +42.066d {+42d 03' 58"} (current),
                 +42.354d {+42d 21' 13"} (1950)
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        84127.70 SOD {23:22:07.70} UT
TRIGGER_INDEX:   146
GRB_PHI:          95.50 [deg]
GRB_THETA:        19.17 [deg]
DELTA_TIME:      7.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     29.41 [sigma]
IMAGE_SIGNIF:    13.33 [sigma]
LC_URL:          sw00522656000msb.lc
SUN_POSTN:        59.17d {+03h 56m 40s}  +20.42d {+20d 25' 03"}
SUN_DIST:        113.46 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.69d {+04h 42m 47s}  +21.62d {+21d 37' 05"}
MOON_DIST:       108.03 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.08, 66.97 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      190.77, 51.41 [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 = 258.35,20.49 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:35:08 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.143d {+42d 08' 34"} (J2000)
POINT_ROLL:      334.565d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84204.48 SOD {23:23:24.48} UT,   76.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.029
N_STARS:         52
X_OFFSET:        320 [pixels]
Y_OFFSET:        624 [pixels]
X_MAX:           1279 [pixels]
Y_MAX:           1583 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00522656000msufc0076.fits
SUN_POSTN:        59.17d {+03h 56m 40s}  +20.42d {+20d 25' 03"}
SUN_DIST:        113.44 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.70d {+04h 42m 48s}  +21.62d {+21d 37' 05"}
MOON_DIST:       108.01 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [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 23:35:53 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.143d {+42d 08' 34"} (J2000)
POINT_ROLL:      334.565d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84204.48 SOD {23:23:24.48} UT,   76.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.029
N_STARS:         52
X_OFFSET:        320 [pixels]
Y_OFFSET:        624 [pixels]
X_MAX:           1279 [pixels]
Y_MAX:           1583 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00522656000msufc0076.fits
SUN_POSTN:        59.17d {+03h 56m 41s}  +20.42d {+20d 25' 03"}
SUN_DIST:        113.44 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.71d {+04h 42m 49s}  +21.62d {+21d 37' 06"}
MOON_DIST:       108.00 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:36:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.143d {+42d 08' 34"} (J2000)
ROLL:            334.565d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84204.48 SOD {23:23:24.48} UT,   76.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359335412
X_OFFSET:        789 [pixels]
Y_OFFSET:        922 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       949
Y_GRB_POS:       1082
BINNING_INDEX:   1
IM_URL:          sw00522656000msuni0085.fits
SUN_POSTN:        59.17d {+03h 56m 41s}  +20.42d {+20d 25' 04"}
SUN_DIST:        113.44 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.71d {+04h 42m 51s}  +21.62d {+21d 37' 07"}
MOON_DIST:       108.00 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:36:22 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.143d {+42d 08' 34"} (J2000)
ROLL:            334.565d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84204.48 SOD {23:23:24.48} UT,   76.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359335412
X_OFFSET:        789 [pixels]
Y_OFFSET:        922 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       949
Y_GRB_POS:       1082
BINNING_INDEX:   1
IM_URL:          sw00522656000msuni0085.fits
SUN_POSTN:        59.17d {+03h 56m 41s}  +20.42d {+20d 25' 04"}
SUN_DIST:        113.44 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.71d {+04h 42m 50s}  +21.62d {+21d 37' 07"}
MOON_DIST:       108.00 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:40:19 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.277d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.145d {+42d 08' 43"} (J2000)
POINT_ROLL:      334.564d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84416.59 SOD {23:26:56.59} UT,   288.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.439
N_STARS:         76
X_OFFSET:        469 [pixels]
Y_OFFSET:        602 [pixels]
X_MAX:           1428 [pixels]
Y_MAX:           1561 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00522656000msufc0288.fits
SUN_POSTN:        59.17d {+03h 56m 41s}  +20.42d {+20d 25' 06"}
SUN_DIST:        113.43 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.74d {+04h 42m 59s}  +21.62d {+21d 37' 11"}
MOON_DIST:       107.98 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [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 23:40:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.277d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.145d {+42d 08' 43"} (J2000)
POINT_ROLL:      334.564d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84416.59 SOD {23:26:56.59} UT,   288.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.439
N_STARS:         76
X_OFFSET:        469 [pixels]
Y_OFFSET:        602 [pixels]
X_MAX:           1428 [pixels]
Y_MAX:           1561 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00522656000msufc0288.fits
SUN_POSTN:        59.17d {+03h 56m 41s}  +20.42d {+20d 25' 06"}
SUN_DIST:        113.43 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.75d {+04h 42m 59s}  +21.62d {+21d 37' 12"}
MOON_DIST:       107.98 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:42:22 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     193276,   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:  24772 TJD;   8846 DOY;   12/135764275/-1075607480
IMG_START_TIME:  19873.14 SOD {05:31:13.14} UT,   22145.4 [sec] since BAT Trigger Time
FILTER:          0, illegal value
EXPOSURE_ID:     216401929
X_OFFSET:        723 [pixels]
Y_OFFSET:        22 [pixels]
WIDTH:           1344 [pixels]
HEIGHT:          1440 [pixels]
X_GRB_POS:       90
Y_GRB_POS:       642
BINNING_INDEX:   4
IM_URL:          sw00522656000msuni0297.fits
SUN_POSTN:        59.17d {+03h 56m 42s}  +20.42d {+20d 25' 07"}
SUN_DIST:         60.79 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       70.76d {+04h 43m 03s}  +21.62d {+21d 37' 14"}
MOON_DIST:        71.66 [deg]
MOON_ILLUM:      1 [%]
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 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:     Mon 21 May 12 23:42:40 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     193276,   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:  24772 TJD;   8846 DOY;   12/135764275/-1075607480
IMG_START_TIME:  19873.14 SOD {05:31:13.14} UT,   22145.4 [sec] since BAT Trigger Time
FILTER:          0, illegal value
EXPOSURE_ID:     216401929
X_OFFSET:        723 [pixels]
Y_OFFSET:        22 [pixels]
WIDTH:           1344 [pixels]
HEIGHT:          1440 [pixels]
X_GRB_POS:       90
Y_GRB_POS:       642
BINNING_INDEX:   4
IM_URL:          sw00522656000msuni0297.fits
SUN_POSTN:        59.17d {+03h 56m 42s}  +20.42d {+20d 25' 07"}
SUN_DIST:         60.79 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       70.77d {+04h 43m 04s}  +21.62d {+21d 37' 14"}
MOON_DIST:        71.66 [deg]
MOON_ILLUM:      1 [%]
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 Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 16x16 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.  
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:     Mon 21 May 12 23:44:15 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.145d {+42d 08' 42"} (J2000)
POINT_ROLL:      334.564d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84995.80 SOD {23:36:35.80} UT,   868.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.511
N_STARS:         190
X_OFFSET:        229 [pixels]
Y_OFFSET:        362 [pixels]
X_MAX:           1668 [pixels]
Y_MAX:           1801 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00522656000msufc0868.fits
SUN_POSTN:        59.17d {+03h 56m 42s}  +20.42d {+20d 25' 08"}
SUN_DIST:        113.43 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.78d {+04h 43m 07s}  +21.62d {+21d 37' 16"}
MOON_DIST:       107.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [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 23:44:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.145d {+42d 08' 42"} (J2000)
POINT_ROLL:      334.564d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84995.80 SOD {23:36:35.80} UT,   868.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.511
N_STARS:         190
X_OFFSET:        229 [pixels]
Y_OFFSET:        362 [pixels]
X_MAX:           1668 [pixels]
Y_MAX:           1801 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00522656000msufc0868.fits
SUN_POSTN:        59.18d {+03h 56m 42s}  +20.42d {+20d 25' 08"}
SUN_DIST:        113.43 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.78d {+04h 43m 08s}  +21.62d {+21d 37' 16"}
MOON_DIST:       107.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 23:45:43 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.145d {+42d 08' 42"} (J2000)
ROLL:            334.564d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84995.80 SOD {23:36:35.80} UT,   868.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359336204
X_OFFSET:        788 [pixels]
Y_OFFSET:        921 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       948
Y_GRB_POS:       1081
BINNING_INDEX:   1
IM_URL:          sw00522656000msuni0877.fits
SUN_POSTN:        59.18d {+03h 56m 42s}  +20.42d {+20d 25' 08"}
SUN_DIST:        113.43 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.79d {+04h 43m 10s}  +21.62d {+21d 37' 18"}
MOON_DIST:       107.96 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [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 23:46:00 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     522656,   Seg_Num: 0
POINT_RA:        214.278d {+14h 17m 07s} (J2000)
POINT_DEC:       +42.145d {+42d 08' 42"} (J2000)
ROLL:            334.564d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  84995.80 SOD {23:36:35.80} UT,   868.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359336204
X_OFFSET:        788 [pixels]
Y_OFFSET:        921 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       948
Y_GRB_POS:       1081
BINNING_INDEX:   1
IM_URL:          sw00522656000msuni0877.fits
SUN_POSTN:        59.18d {+03h 56m 42s}  +20.42d {+20d 25' 08"}
SUN_DIST:        113.43 [deg]   Sun_angle= -10.3 [hr] (East of Sun)
MOON_POSTN:       70.80d {+04h 43m 11s}  +21.62d {+21d 37' 18"}
MOON_DIST:       107.96 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       79.14, 66.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      190.74, 51.42 [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 #13318
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and G. Stratta (ASDC) report on behalf of the Swift Team:
At 23:22:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120521C (trigger=522656). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 214.290, +42.123 which is
```
   RA(J2000) = 14h 17m 09s
   Dec(J2000) = +42d 07' 23"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single FRED structure with a duration of about 20 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 23:23:16.8 UT, 69.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 214.28671, 42.14311 which is equivalent to:
```
   RA(J2000)  = 14h 17m 08.81s
   Dec(J2000) = +42d 08' 35.2"
```
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This location is 72 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. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.05 x 10^20 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 7.43e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 76 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. Results from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is W. H. Baumgartner (wayne 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 Circular #13319
Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 120521C detected by SWIFT (trigger 522656) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France.
The observations started 23 min after the GRB trigger. The elevation of the field decreased from 68 degrees above horizon but humidity was higher than 93% until 23 min after the trigger preventing the record of the beginning of the event.
We co-added a series of exposures. No OT was found in the XRT error box (Baumgartner et al. GCNC 13318).
```
start   stop
23min   37min   R > 19.4
```
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular #13320
David Bersier (LJMU) reports on behalf of the Liverpol GRB collaboration:
The Liverpool Telescope responded automatically to Swift trigger 522656 (Baumgartner et al, GCN 13318) 11 minutes after the trigger.
We do not detect any variable source inside the XRT error circle. A representative upper limit is R=21.5 at 35 minutes after the burst, calibrated with respect to USNO-B.
GCN Circular #13321
A. De Cia (U. of Iceland), A. Sandberg (Oskar Klein Centre), J.Hjorth (DARK), N.R. Tanvir (U. of Leicester) and P. Jakobsson (U. of Iceland) report:
We observed the field of GRB 120521C (Baumgartner et al., GCN 13318) with the NOT equipped with MOSCA in the Sloan r and i filters for 10 minutes, starting at 0:09 UT (47 min after the GRB trigger).
No significant source was detected at the burst position, down to r > 23.6 mag, calibrated against SDSS stars.
GCN Circular #13322
A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), M. Hrudkova (ING) report for a larger collaboration:
"We obtained observations of GRB 120521C (Baumgartner et al. GCN 13318) with the William Herschel Telescope equipped with ACAM in the r and z-bands. Our observations started at 00:01UT, 39 minutes after the burst trigger. We do not detect any afterglow candidates within the XRT error circle. Provisional limits, calibrated against SDSS suggest r>24.0, z>22.5"
GCN Circular #13323
M. Jelinek (IAA-CSIC), P. Kubanek (IP AS CR), A.J. Castro-Tirado (IAA-CSIC), J. Gorosabel (IAA-CSIC), report on behalf of a larger collaboration:
"The 0.3-m robotic telescope at the BOOTES-1 station in south Spain (INTA-CEDEA) responded automatically to GRB 120521C (Baumgartner et al., GCN Circ. 13318), performing clear-band observations on May 21.98180 -- 21.98863 UT (11.7 -- 21.5 minutes post burst). No object is detected within the XRT circle down to R~20.5"
GCN Circular #13324
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 2020 s of XRT Photon Counting mode data and 2 UVOT images for GRB 120521C, 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 = 214.28648, +42.14467 which is equivalent to:
```
RA (J2000): 14h 17m 8.76s
Dec (J2000): +42d 08' 40.8"
```
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 #13325
A. N. Morgan (UC Berkeley) reports:
We observed the field of GRB 120521C (Baumgartner et al., GCN 13318) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2012-May-22 03h52m27s UT, ~4.5 hours after the Swift trigger. In mosaics (effective exposure time of 1568 s) taken simultaneously in the J, H, and Ks filters, we do not detect any source within the enhanced XRT error circle (Beardmore et al. GCN 13324).
```
post burst
t_mid (hr) exp.(hr) filt  U. Limit (3 sig)
4.99      0.44     J     > 18.5
4.99      0.44     H     > 17.6
4.99      0.44     Ks    > 16.0
```
All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.
GCN Circular #13329
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
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)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB120521C 60 sec after notice time and 715 sec after GRB time at 2012-05-21 23:34:03 UT in two polarizations. We haven`t found optical transient within Swift BAT error-box (Baumgartner et al., GCN 13318) . The 5-sigma upper limit has been about 20.0 mag for mean time after trigger 1492s (total exposition 1370s).
The direct copy from MASTER DataBase is:
```
Pro.type   Date      time      Exp.time	Limit  Filt.	Tube.

Alert 	2012-05-21 23:34:03	130	17.7	P|	EAST
Alert 	2012-05-21 23:34:03	130	18.2	P-	WEST
Alert 	2012-05-21 23:34:03	130	18.2	P-	WEST
Alert 	2012-05-21 23:36:45	160	18.6	P-	WEST
Alert 	2012-05-21 23:36:45	160	18.1	P|	EAST
Alert 	2012-05-21 23:39:48	180	18.9	P-	WEST
Alert 	2012-05-21 23:39:48	180	18.4	P|	EAST
Alert 	2012-05-21 23:43:13	180	18.4	P|	EAST
Alert 	2012-05-21 23:43:13	180	19.0	P-	WEST
Alert 	2012-05-21 23:46:37	180	18.3	P|	EAST
Alert 	2012-05-21 23:46:38	180	18.4	P-	WEST
Alert 	2012-05-21 23:50:02	180	18.4	P|	EAST
Alert 	2012-05-21 23:50:02	180	19.1	P-	WEST
Alert 	2012-05-21 23:53:27	180	18.4	P|	EAST
Alert 	2012-05-21 23:53:27	180	19.1	P-	WEST
Alert 	2012-05-21 23:56:57	180	18.4	P|	EAST
Alert 	2012-05-21 23:56:57	180	19.0	P-	WEST 
AddWest 2012-05-21 23:34:03    1370     20.0    P-      WEST
```
The message may be cited.
GCN Circular #13331
S. R. Oates (MSSL-UCL) and W. H. Baumgartner (GSFC/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120521C 77 s after the BAT trigger (Baumgartner et al., GCN Circ. 13318). No optical afterglow consistent with the XRT position (Beardmore et al., GCN Circ. 13324) 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            77          227          147         >20.9
u_FC               289          539          246         >20.4
white               77         2226          470         >21.7
v                  621         2276          194         >19.8
b                  546         2201          156         >20.4
u                  289         2177          343         >20.7
w1                 670         2325          194         >20.4
m2                 645         2128          136         >19.9
w2                 596         2251          156         >20.4
```
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 #13332
D. A. Perley (Caltech), O. Yaron (Weizmann), Y. Cao, and S. R. Kulkarni (Caltech) report:
We observed the position of GRB 120521C (Baumgartner et al., GCN 13318) with the Keck I 10m telescope (+LRIS) starting at 10:39 UT on 2012-05-22. We acquired a total of 1200s of imaging in I-band and 1360s in g-band. Seeing conditions were relatively poor (1.5").
At the position of the enhanced XRT error circle (Beardmore et al., GCN 13324) we clearly identify a extended source in both the g-band and I-band images. It appears to consist of at least two components; a red source at the southern edge of the XRT error circle and a bluer source at the western edge of the error circle. The relation of these sources to each other and to GRB 120521C is not yet clear, but they could represent a host-galaxy merger system, an afterglow superposed on a host, or two unrelated galaxies at different redshifts.
The early nondetections of an afterglow (e.g. Klotz et al., GCN 13319; Bersier et al., GCN 13320; De Cia et al., GCN 13321; Levan et al., GCN 13322; Jelinek et al., GCN 13323; Morgan et al., GCN 13325; Gorbovskoy et al., GCN 13329; Oates et al., GCN 13331) are characteristic of a dark burst. Further observations of this event (in particular in the NIR) are encouraged.
An image of the field is posted to: http://www.astro.caltech.edu/~dperley/gcn/120521c/120521c.png
GCN Circular #13333
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), 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-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120521C (trigger #522656) (Baumgartner, et al., GCN Circ. 13318). The BAT ground-calculated position is RA, Dec = 214.288, 42.144 deg, which is
```
   RA(J2000)  =  14h 17m 09.1s 
   Dec(J2000) = +42d 08' 39.8" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%.
The mask-weighted light curves shows a FRED peak starting at ~T-2 sec, peaking at ~T+1 sec, abd ending at ~T+40 sec. T90 (15-350 keV) is 26.7 +- 4.4 sec (estimated error including systematics).
The time-averaged spectrum from T-1.03 to T+31.84 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.73 +- 0.11. The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.02 sec in the 15-150 keV band is 1.9 +- 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/522656/BA/
GCN Circular #13334
M.C. Stroh (PSU), D.N. Burrows (PSU), P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), J.P. Osborne (U. Leicester), A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU) and W.H. Baumgartner report on behalf of the Swift-XRT team:
We have analysed 7.2 ks of XRT data for GRB 120521C (Baumgartner et al. GCN Circ. 13318), from 59 s to 29.2 ks after the BAT trigger. The data comprise 101 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 13324).
The light curve can be modelled with an initial power-law decay with an index of alpha=2.78 (+0.19, -0.17), followed by a break at T+489 s to an alpha of 0.51 (+0.11, -0.10).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.78 (+0.25, -0.16). The best-fitting absorption column is consistent with the Galactic value of 1.0 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 3.9 x 10^-11 (4.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     0 (+4.2, -0) x 10^20 cm^-2
Galactic foreground: 1.0 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.78 (+0.25, -0.16)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00522656.
This circular is an official product of the Swift-XRT team.
GCN Circular #13336
A. Zauderer and E. Berger (Harvard) report on behalf of a larger collaboration:
"We observed the position of GRB 120521C (GCN 13318) beginning 2012 May 22.12 (3.6 hours after the burst) with the EVLA. At a mean frequency of 21.8 GHz, we find no significant radio emission within the refined Swift-XRT error circle (GCN 13324) to a 3-sigma limit of ~50 uJy."
GCN Circular #13337
D. A. Kann, B. Stecklum and U. Laux (TLS Tautenburg) report:
We observed to position of Swift GRB 120521C (Trigger 522656, Baumgartner et al., GCN 13318) with the TLS 1.34m Schmidt telescope. Conditions were mediocre, with good seeing but bad transparency. Observations were triggered manually and began 28 minutes after the trigger (17 minutes after the alert). We obtained 5 x 60 s images in Rc, 4 x 180 s images also in Rc, and 1 x 600 s each in Z and Ic. The Ic image is affected in depth by passing clouds.
At the position of the enhanced X-ray afterglow (Beardmore et al., GCN 13324), we do not detect any source, in agreement with earlier results (Klotz et al., GCN 13319; Bersier et al., GCN 13320; De Cia et al., GCN 13321; Levan et al., GCN 13322; Jelinek et al., GCN 13323; Morgan et al., GCN 13325; Gorbovskoy et al., GCN 13329; Oates et al., GCN 13331). The possible host galaxy (Perley et al., GCN 13332) is not detected.
We us the SDSS star at RA, Dec. (J2000) = 14:17:02.836, +42:6:07.62 (214.26181759, 42.10211787, catalog ID 1237661874023500000) as a comparison star. Using the transformations of Lupton (2005), we find Rc = 18.33, Ic = 17.93 and Z = 17.78 for this star.
We find the following 2 sigma limiting magnitudes:
```
Time (days)	Exposure (s)	Filter	UL
0.019827	1 x 60		Rc	21.0
0.022275	5 x 60		Rc	21.8
0.027171	1 x 180		Rc	21.5
0.030760	4 x 180		Rc	22.5
0.040247	1 x 600		Z	20.2
0.048757	1 x 600		Ic	19.3
```
We note that while the non-detections we as well as other telescopes have found point to this being a dark GRB, the X-ray absorption seen by Swift is small. The Keck detection of a possible host galaxy in g' band likely rules out a high-z interpretation, though.
No further observations are planned.
This message may be cited.
GCN Circular #13343
A. Zauderer and E. Berger (Harvard) report on behalf of a larger collaboration:
"We re-observed the position of GRB 120521C (GCN 13318) on 2012 May 23.12 UT (1.15 d after the burst) with the EVLA at 21.8 GHz. Within the enhanced Swift-XRT error circle (GCN 13324) we detect a brightening radio source with a flux density that is about a factor of two above our early 3-sigma limit of 50 uJy (GCN 13336). We conclude that this is the radio afterglow of GRB 120521C. Follow-up observations at multiple frequencies are in progress."
GCN Circular #13344
A. Zauderer, E. Berger and T. Laskar (Harvard) report on behalf of a larger collaboration:
"Further to GCN 13343, we note that the EVLA 21.8 GHz brightening source within the XRT enhanced error circle of GRB 120521C (GCNs 13318, 13324) is located at (J2000):
```
RA:   14:17:08.802 (+/- 0.002)
Dec: +42:08:41.22  (+/- 0.02).
```
This position appears to be offset from the two galaxies at the edge of the Swift-XRT error circle based on the image provided by Perley et al. in GCN 13332."
GCN Circular #13348
N. R. Tanvir, K. Wiersema (U. Leicester), A. J. Levan (U. Warwick), A. Cucchiara (UCSC/UCO Lick), D. Perley (Caltech), P. Hirst (Gemini), T. Carroll, T. Kerr, W. Varricatt (JACH), C. Farina, M. Hrudkova (ING), L. Ker (Edinburgh) report on behalf of a larger collaboration:
We have combined observations of GRB 120521C (Baumgartner et al. GCN 13318) made using the WHT (Levan et al., GCN 13322), Keck (Perley et al. GCN 13332), UKIRT and Gemini-N telescopes across the optical-IR region in r,i,z,J,H,K.
Analysis of further WHT z-band imaging, obtained at 01:54 UT, 2 hours after our initial epoch (Levan et al. GCN 13322) shows a faint source within the XRT error circle. This source is also seen at high confidence in z-band imaging obtained with Gemini-N at 07:03 UT, and photometry shows that it brightened by 0.5 magnitudes over this period, suggesting it is the afterglow of GRB 120521C. This source is only very weakly visible in contemporaneous I-band imaging obtained with Keck (Perley et al. GCN 13332), and this indicates a red colour i-z >2.3 . However, the source is not detected in our initial reductions of the UKIRT WFCAM imaging in JHK, suggesting that z-K < 1.3 (AB, corresponding to f(nu) ~ nu^-beta with beta<1.3). This is indicative of a high-redshift, rather than a highly reddened afterglow. We note that the position of the afterglow candidate in our data matches the radio position reported by Zauderer et al (GCN 13344) within our calibration uncertainty of ~0.3 arcseconds.
Gemini-North GMOS spectroscopy was obtained in poor conditions, using the R400 grating centered at 8000 A, giving a wavelength range of approximately 5850-10100 A. Observations (2 x 1800 s) started at 12:03 UT on 23 May 2012. We used the GMOS Nod&Shuffle observing mode to improve skyline subtraction.
In the resulting spectrum, a weak trace is seen at the expected location, which is only detected redward of ~8700 A. The absence of any emission bluewards of this wavelength is suggestive of a high redshift of this source, z~6.0. The low signal of the trace precludes detection of absorption lines.
Further analysis of the data is ongoing.
1307.6586 from 26 Jul 13
T. Laskar et al.: GRB 120521C at z~6 and the Properties of High-redshift GRBs
We present optical, near-infrared, and radio observations of the afterglow of GRB 120521C. By modeling the multi-wavelength dataset, we derive a photometric redshift of z~6.0, which we confirm with a low signal-to-noise ratio spectrum of the afterglow. We find that a model with a constant-density environment provides a good fit to the afterglow data, with an inferred density of 0.05/cm^3. The radio observations reveal the presence of a jet break at 7 d, corresponding to a jet opening angle of ~ 3 deg. The beaming-corrected gamma-ray and kinetic energies are both ~ 3e50 erg. We quantify the uncertainties in our results using a detailed Markov Chain Monte Carlo analysis, which allows us to uncover degeneracies between the physical parameters of the explosion. To compare GRB 120521C to other high-redshift bursts in a uniform manner we re-fit all available afterglow data for the two other bursts at z>6 with radio detections (GRBs 050904 and 090423). We find a jet break at ~ 15 d for GRB 090423, in contrast to previous work. Based on these three events, we find that GRBs at z>6 appear to explode in constant-density environments, and exhibit a wide range of energies and densities that span the range inferred for lower redshift bursts. On the other hand, we find a hint for narrower jets in the z>6 bursts, potentially indicating a larger true event rate at these redshifts. Overall, our results indicate that long GRBs share a common progenitor population at least to z~8.

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Jochen Greiner, last update: 26-Jul-2013 [Disclaimer]