Gamma-ray Burst 120521A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 06:00:06 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     522578,   Seg_Num: 0
GRB_RA:          148.693d {+09h 54m 46s} (J2000),
                 148.810d {+09h 55m 14s} (current),
                 148.222d {+09h 52m 53s} (1950)
GRB_DEC:         -49.419d {-49d 25' 08"} (J2000),
                 -49.478d {-49d 28' 41"} (current),
                 -49.182d {-49d 10' 54"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2566 [cnts]    Image_Peak=221 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   470     E_range: 25-100 keV
BKG_INTEN:       24071 [cnts]
BKG_TIME:        21567.76 SOD {05:59:27.76} UT
BKG_DUR:         8 [sec]
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        21582.93 SOD {05:59:42.93} UT
GRB_PHI:         -32.75 [deg]
GRB_THETA:        13.14 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     24.69 [sigma]
IMAGE_SIGNIF:    11.48 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  +1  +0  +1 +26  +0 
SUN_POSTN:        58.43d {+03h 53m 44s}  +20.27d {+20d 16' 20"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.34d {+04h 05m 20s}  +21.01d {+21d 00' 19"}
MOON_DIST:       104.23 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.91,  3.96 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      179.17,-56.23 [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 = 229.41,10.82 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 06:01:34 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.706d {+09h 54m 49s} (J2000)
POINT_DEC:       -49.413d {-49d 24' 47"} (J2000)
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21656.65 SOD {06:00:56.65} UT,   73.7 [sec] since BAT Trigger Time
COUNTS:          38    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        4    Max_iter_allowed= 4
ERROR_CODE:      2
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Algorithm did not converge; too many iterations.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 06:03:59 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     522578,   Seg_Num: 0
GRB_RA:          148.693d {+09h 54m 46s} (J2000),
                 148.810d {+09h 55m 14s} (current),
                 148.222d {+09h 52m 53s} (1950)
GRB_DEC:         -49.419d {-49d 25' 08"} (J2000),
                 -49.478d {-49d 28' 41"} (current),
                 -49.182d {-49d 10' 54"} (1950)
GRB_DATE:        16068 TJD;   142 DOY;   12/05/21
GRB_TIME:        21582.93 SOD {05:59:42.93} UT
TRIGGER_INDEX:   470
GRB_PHI:         -32.75 [deg]
GRB_THETA:        13.14 [deg]
DELTA_TIME:      -76.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     24.69 [sigma]
IMAGE_SIGNIF:    11.48 [sigma]
LC_URL:          sw00522578000msb.lc
SUN_POSTN:        58.44d {+03h 53m 45s}  +20.27d {+20d 16' 22"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.37d {+04h 05m 29s}  +21.01d {+21d 00' 30"}
MOON_DIST:       104.21 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.91,  3.96 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      179.17,-56.23 [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 = 229.41,10.82 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 06:04:31 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.706d {+09h 54m 49s} (J2000)
POINT_DEC:       -49.413d {-49d 24' 46"} (J2000)
POINT_ROLL:      283.306d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21659.94 SOD {06:00:59.94} UT,   77.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.706
N_STARS:         190
X_OFFSET:        506 [pixels]
Y_OFFSET:        487 [pixels]
X_MAX:           1465 [pixels]
Y_MAX:           1446 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00522578000msufc0077.fits
SUN_POSTN:        58.44d {+03h 53m 45s}  +20.27d {+20d 16' 23"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.37d {+04h 05m 30s}  +21.01d {+21d 00' 32"}
MOON_DIST:       104.21 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.91,  3.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 06:05:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.706d {+09h 54m 49s} (J2000)
POINT_DEC:       -49.413d {-49d 24' 46"} (J2000)
POINT_ROLL:      283.306d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21659.94 SOD {06:00:59.94} UT,   77.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.706
N_STARS:         190
X_OFFSET:        506 [pixels]
Y_OFFSET:        487 [pixels]
X_MAX:           1465 [pixels]
Y_MAX:           1446 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00522578000msufc0077.fits
SUN_POSTN:        58.44d {+03h 53m 45s}  +20.27d {+20d 16' 23"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.38d {+04h 05m 31s}  +21.01d {+21d 00' 34"}
MOON_DIST:       104.21 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.91,  3.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 06:05:52 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     522578,   Seg_Num: 0
GRB_RA:          148.7253d {+09h 54m 54.07s} (J2000),
                 148.8422d {+09h 55m 22.13s} (current),
                 148.2539d {+09h 53m 00.94s} (1950)
GRB_DEC:         -49.4178d {-49d 25' 04.0"} (J2000),
                 -49.4768d {-49d 28' 36.3"} (current),
                 -49.1804d {-49d 10' 49.6"} (1950)
GRB_ERROR:       3.9 [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:  21672.00 SOD {06:01:12.00} UT,   89.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        58.44d {+03h 53m 45s}  +20.27d {+20d 16' 23"}
SUN_DIST:        105.53 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.39d {+04h 05m 33s}  +21.01d {+21d 00' 36"}
MOON_DIST:       104.22 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.93,  3.97 [deg] galactic lon,lat of the burst
ECL_COORDS:      179.20,-56.22 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
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:        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 06:06:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.706d {+09h 54m 49s} (J2000)
POINT_DEC:       -49.413d {-49d 24' 46"} (J2000)
ROLL:            283.306d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21659.94 SOD {06:00:59.94} UT,   77.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359272868
X_OFFSET:        825 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00522578000msuni0086.fits
SUN_POSTN:        58.44d {+03h 53m 45s}  +20.27d {+20d 16' 23"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.39d {+04h 05m 33s}  +21.01d {+21d 00' 37"}
MOON_DIST:       104.20 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.91,  3.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 06:06:17 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.706d {+09h 54m 49s} (J2000)
POINT_DEC:       -49.413d {-49d 24' 46"} (J2000)
ROLL:            283.306d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21659.94 SOD {06:00:59.94} UT,   77.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     359272868
X_OFFSET:        825 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00522578000msuni0086.fits
SUN_POSTN:        58.44d {+03h 53m 45s}  +20.27d {+20d 16' 24"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.39d {+04h 05m 33s}  +21.01d {+21d 00' 37"}
MOON_DIST:       104.20 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.91,  3.97 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 #13302
M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), B. Gendre (ASDC), D. M. Palmer (LANL) and G. Stratta (ASDC) report on behalf of the Swift Team:
At 05:59:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120521A (trigger=522578). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 148.693, -49.419 which is
```
   RA(J2000) = 09h 54m 46s
   Dec(J2000) = -49d 25' 08"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short FRED structure with a duration of about 0.7 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0.25 sec after the trigger.
The XRT began observing the field at 06:00:56.6 UT, 73.8 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 148.72544, -49.41760 which is equivalent to:
```
   RA(J2000)  = 09h 54m 54.11s
   Dec(J2000) = -49d 25' 03.4"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 76 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 consistent with the Galactic value of 2.08 x 10^21 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 77 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 large, but uncertain extinction expected.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 21 May 12 06:13:21 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.707d {+09h 54m 50s} (J2000)
POINT_DEC:       -49.415d {-49d 24' 54"} (J2000)
POINT_ROLL:      283.304d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21872.32 SOD {06:04:32.32} UT,   289.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.911
N_STARS:         190
X_OFFSET:        266 [pixels]
Y_OFFSET:        247 [pixels]
X_MAX:           1705 [pixels]
Y_MAX:           1686 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00522578000msufc0289.fits
SUN_POSTN:        58.44d {+03h 53m 46s}  +20.27d {+20d 16' 27"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.45d {+04h 05m 48s}  +21.02d {+21d 00' 58"}
MOON_DIST:       104.17 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.92,  3.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 06:13:47 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.707d {+09h 54m 50s} (J2000)
POINT_DEC:       -49.415d {-49d 24' 54"} (J2000)
POINT_ROLL:      283.304d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21872.32 SOD {06:04:32.32} UT,   289.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.911
N_STARS:         190
X_OFFSET:        266 [pixels]
Y_OFFSET:        247 [pixels]
X_MAX:           1705 [pixels]
Y_MAX:           1686 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00522578000msufc0289.fits
SUN_POSTN:        58.44d {+03h 53m 46s}  +20.27d {+20d 16' 27"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.46d {+04h 05m 49s}  +21.02d {+21d 00' 59"}
MOON_DIST:       104.17 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.92,  3.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 06:14:02 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     522578,   Seg_Num: 0
GRB_RA:          148.7247d {+09h 54m 53.92s} (J2000),
                 148.8416d {+09h 55m 21.99s} (current),
                 148.2533d {+09h 53m 00.80s} (1950)
GRB_DEC:         -49.4172d {-49d 25' 01.9"} (J2000),
                 -49.4762d {-49d 28' 34.2"} (current),
                 -49.1798d {-49d 10' 47.4"} (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:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21672.00 SOD {06:01:12.00} UT,   89.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        58.44d {+03h 53m 46s}  +20.27d {+20d 16' 27"}
SUN_DIST:        105.52 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.46d {+04h 05m 50s}  +21.02d {+21d 01' 00"}
MOON_DIST:       104.18 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.93,  3.97 [deg] galactic lon,lat of the burst
ECL_COORDS:      179.20,-56.22 [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 06:15:03 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.707d {+09h 54m 50s} (J2000)
POINT_DEC:       -49.415d {-49d 24' 54"} (J2000)
ROLL:            283.304d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21872.32 SOD {06:04:32.32} UT,   289.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     359273080
X_OFFSET:        825 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00522578000msuni0298.fits
SUN_POSTN:        58.44d {+03h 53m 46s}  +20.27d {+20d 16' 28"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.47d {+04h 05m 52s}  +21.02d {+21d 01' 03"}
MOON_DIST:       104.16 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.92,  3.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 06:15:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     522578,   Seg_Num: 0
POINT_RA:        148.707d {+09h 54m 50s} (J2000)
POINT_DEC:       -49.415d {-49d 24' 54"} (J2000)
ROLL:            283.304d
IMG_START_DATE:  16068 TJD;   142 DOY;   12/05/21
IMG_START_TIME:  21872.32 SOD {06:04:32.32} UT,   289.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     359273080
X_OFFSET:        825 [pixels]
Y_OFFSET:        806 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       985
Y_GRB_POS:       966
BINNING_INDEX:   1
IM_URL:          sw00522578000msuni0298.fits
SUN_POSTN:        58.44d {+03h 53m 46s}  +20.27d {+20d 16' 28"}
SUN_DIST:        105.51 [deg]   Sun_angle= -6.0 [hr] (East of Sun)
MOON_POSTN:       61.47d {+04h 05m 52s}  +21.02d {+21d 01' 04"}
MOON_DIST:       104.16 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      275.92,  3.96 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      179.18,-56.22 [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 #13303
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 120521A detected by SWIFT (trigger 522578) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile.
The observations started 35.2s after the GRB trigger (15.1s after the notice). The elevation of the field decreased from 10 degrees above horizon and weather conditions were good.
The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT in the XRT position (Chester et al. GCNC 13302) with a limiting magnitude of: t0+35.2s to t0+95.2s : R > 15.8
The second image is 30.0s exposure in tracking mode: t0+108.9s to t0+138.9s : R > 16.5
We co-added a series of exposures: t0+109s to t0+533s : R > 17.4
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
GCN Circular #13304
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 508 s of XRT Photon Counting mode data and 1 UVOT images for GRB 120521A, 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 = 148.72462, -49.41733 which is equivalent to:
```
RA (J2000): 09h 54m 53.91s
Dec (J2000): -49d 25' 02.4"
```
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 #13310
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), 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-239 to T+363 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120521A (trigger #522578) (Chester, et al., GCN Circ. 13302). The BAT ground-calculated position is RA, Dec = 148.692, -49.422 deg, which is
```
   RA(J2000)  =  09h 54m 46.1s 
   Dec(J2000) = -49d 25' 17.8" 
```
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shows FRED pulse starting at ~T+0.0, peaking at ~T+0.1, and ending at ~T+1.0 sec. T90 (15-350 keV) is 0.45 +- 0.08 sec (estimated error including systematics).
The time-averaged spectrum from T+0.02 to T+0.56 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.98 +- 0.22. The fluence in the 15-150 keV band is 7.8 +- 1.1 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.21 sec in the 15-150 keV band is 0.9 +- 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/522578/BA/
GCN Circular #13312
S. R. Oates (MSSL-UCL) and M. M. Chester (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120521A 77 s after the BAT trigger (Chester et al., GCN Circ. 13302). No optical afterglow consistent with the XRT position (Goad et al., GCN Circ. 13304) 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         >21.4
u_FC               289          539          246         >20.9
white               77         5491          363         >21.9
v                 4266         5901          393         >19.7
b                  545        11343          766         >21.9
u                  289        10775         1386         >21.6
w1                4676         6312          393         >20.4
m2                4470         6106          393         >20.6
w2                4061         5697          393         >20.2
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.43 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #13326
J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA) and M.M. Chester report on behalf of the Swift-XRT team:
We have analysed 4.3 ks of XRT data for GRB 120521A (Chester et al. GCN Circ. 13302), from 83 s to 11.3 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 13304).
The light curve can be modelled with a power-law decay with a decay index of alpha=anf (+/anf).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.81 (+0.36, -0.29). The best-fitting absorption column is 2.6 (+1.4, -0.5) x 10^21 cm^-2, consistent with the Galactic value of 2.1 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 4.6 x 10^-11 (6.3 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.6 (+1.4, -0.5) x 10^21 cm^-2
Galactic foreground: 2.1 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.81 (+0.36, -0.29)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00522578.
This circular is an official product of the Swift-XRT team.
GCN Circular #13327
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
There was an error in GCN 13326: the light curve decay slope was reported as infinity.
The XRT light curve in fact shows a plateau (alpha=0.2 +/-0.4) until T0+270 seconds. After this it undergoes an extremely sharp decay (alpha~10) and is not detected in X-rays after T0+1ks.
GCN Circular #13335
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 120521A (Swift trigger 522578; Chester et al., GCN 13302) 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 22:53 UT on 2012-05-21, 16.9 h after the GRB trigger, and lasted for 100 minutes. They were performed under good sky conditions at an average seeing of 0.9 and at an average airmass of 1.1.
Using an exposure of 50 minutes in the optical and 40 minutes in the NIR we do not detect any source within the Swift-XRT error circle reported by Goad et al. (GCN 13304). Preliminary observed upper limits (AB mags) are:
```
g' > 25.5
r' > 25.0
i' > 24.0
z' > 23.7
J > 20.9
H > 20.3
K > 19.1
```
The given limits are derived based on calibrating the images against 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)= 0.43 mag (Schlegel et al. 1998).
GCN Circular #13338
P. Hancock, T. Murphy, B. Gaensler, M. Bell, D. Burlon (University of Sydney/CAASTRO), A. de Ugarte Postigo (Dark Cosmology / IAA)
We observed GRB120521A (GCN13302) with the Australia Telescope Compact Array at 34GHz for 112 mins centered on 07:55UT May 22 2012 (T0+1.08days).
We detect no radio source at the location of the GRB (GCN13304) and place a 3sigma upper limit of 95uJy on the flux of an afterglow.
These observations were obtained as part of ATCA project C2689. We thank the observatory staff for their support and scheduling the observations. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.
GCN Report 414.1
GCN_Report 414.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_414_1.pdf by D. Grupe at PSU titled: "Swift Observations of GRB 120521A"

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Jochen Greiner, last update: 10-Jan-2013 [Disclaimer]