Gamma-ray Burst 110520A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:29:18 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     453747,   Seg_Num: 0
GRB_RA:          134.375d {+08h 57m 30s} (J2000),
                 134.589d {+08h 58m 21s} (current),
                 133.432d {+08h 53m 44s} (1950)
GRB_DEC:         +56.402d {+56d 24' 06"} (J2000),
                 +56.357d {+56d 21' 27"} (current),
                 +56.595d {+56d 35' 42"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       7615 [cnts]    Image_Peak=257 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   271     E_range: 50-350 keV
BKG_INTEN:       69603 [cnts]
BKG_TIME:        73697.02 SOD {20:28:17.02} UT
BKG_DUR:         24 [sec]
GRB_DATE:        15701 TJD;   140 DOY;   11/05/20
GRB_TIME:        73728.19 SOD {20:28:48.19} UT
GRB_PHI:          14.85 [deg]
GRB_THETA:        30.11 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     15.90 [sigma]
IMAGE_SIGNIF:    7.87 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +3  -2  +0  +0 -39  +0 
SUN_POSTN:        57.28d {+03h 49m 06s}  +20.04d {+20d 02' 15"}
SUN_DIST:         66.45 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      284.72d {+18h 58m 53s}  -20.94d {-20d 56' 18"}
MOON_DIST:       138.26 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.68, 39.59 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      119.14, 37.36 [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 = 263.04,12.66 [deg].

red DSS finding chart ps-file

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:34:23 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     3789365,   Seg_Num: 196
GRB_RA:          134.375d {+08h 57m 30s} (J2000),
                 134.589d {+08h 58m 21s} (current),
                 133.432d {+08h 53m 44s} (1950)
GRB_DEC:         +56.402d {+56d 24' 06"} (J2000),
                 +56.357d {+56d 21' 27"} (current),
                 +56.595d {+56d 35' 42"} (1950)
GRB_DATE:        15701 TJD;   140 DOY;   11/05/20
GRB_TIME:        73728.19 SOD {20:28:48.19} UT
TRIGGER_INDEX:   271
GRB_PHI:          14.85 [deg]
GRB_THETA:        30.11 [deg]
DELTA_TIME:      -24138.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    0.00 [sigma]
LC_URL:          sw00453747000msb.lc
SUN_POSTN:        57.28d {+03h 49m 07s}  +20.04d {+20d 02' 17"}
SUN_DIST:         66.45 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      284.77d {+18h 59m 05s}  -20.93d {-20d 55' 47"}
MOON_DIST:       138.27 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.68, 39.59 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      119.14, 37.36 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!  
COMMENTS:           
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 = 263.04,12.66 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:42:13 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.322d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.416d {+56d 24' 58"} (J2000)
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  73828.34 SOD {20:30:28.34} UT,   100.1 [sec] since BAT Trigger Time
COUNTS:          32    Min_needed= 20
STD_DEV:         30.24   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      3
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Standard deviation too large.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:43:56 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.322d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.416d {+56d 24' 57"} (J2000)
POINT_ROLL:      270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  73831.89 SOD {20:30:31.89} UT,   103.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.720
N_STARS:         103
X_OFFSET:        241 [pixels]
Y_OFFSET:        585 [pixels]
X_MAX:           1200 [pixels]
Y_MAX:           1544 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00453747000msufc0103.fits
SUN_POSTN:        57.29d {+03h 49m 09s}  +20.04d {+20d 02' 22"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.86d {+18h 59m 27s}  -20.91d {-20d 54' 47"}
MOON_DIST:       138.31 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.66, 39.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.37 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:44:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.322d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.416d {+56d 24' 57"} (J2000)
POINT_ROLL:      270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  73831.89 SOD {20:30:31.89} UT,   103.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.720
N_STARS:         103
X_OFFSET:        241 [pixels]
Y_OFFSET:        585 [pixels]
X_MAX:           1200 [pixels]
Y_MAX:           1544 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00453747000msufc0103.fits
SUN_POSTN:        57.29d {+03h 49m 09s}  +20.04d {+20d 02' 22"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.87d {+18h 59m 28s}  -20.91d {-20d 54' 45"}
MOON_DIST:       138.31 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.66, 39.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.37 [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:     Fri 20 May 11 20:45:19 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.322d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.416d {+56d 24' 57"} (J2000)
ROLL:            270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  73831.89 SOD {20:30:31.89} UT,   103.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327616238
X_OFFSET:        560 [pixels]
Y_OFFSET:        904 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       720
Y_GRB_POS:       1064
BINNING_INDEX:   1
IM_URL:          sw00453747000msuni0110.fits
SUN_POSTN:        57.29d {+03h 49m 09s}  +20.04d {+20d 02' 23"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.88d {+18h 59m 30s}  -20.91d {-20d 54' 39"}
MOON_DIST:       138.31 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.66, 39.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.37 [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:     Fri 20 May 11 20:45:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.322d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.416d {+56d 24' 57"} (J2000)
ROLL:            270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  73831.89 SOD {20:30:31.89} UT,   103.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327616238
X_OFFSET:        560 [pixels]
Y_OFFSET:        904 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       720
Y_GRB_POS:       1064
BINNING_INDEX:   1
IM_URL:          sw00453747000msuni0110.fits
SUN_POSTN:        57.29d {+03h 49m 09s}  +20.04d {+20d 02' 23"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.88d {+18h 59m 31s}  -20.91d {-20d 54' 36"}
MOON_DIST:       138.31 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.66, 39.56 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.37 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:46:44 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     453747,   Seg_Num: 0
GRB_RA:          134.3420d {+08h 57m 22.08s} (J2000),
                 134.5559d {+08h 58m 13.42s} (current),
                 133.3980d {+08h 53m 35.51s} (1950)
GRB_DEC:         +56.4267d {+56d 25' 36.1"} (J2000),
                 +56.3823d {+56d 22' 56.3"} (current),
                 +56.6196d {+56d 37' 10.7"} (1950)
GRB_ERROR:       3.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  73896.00 SOD {20:31:36.00} UT,   167.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        57.29d {+03h 49m 09s}  +20.04d {+20d 02' 24"}
SUN_DIST:         66.42 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      284.89d {+18h 59m 34s}  -20.91d {-20d 54' 30"}
MOON_DIST:       138.30 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.65, 39.56 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.11, 37.38 [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 Circular #12020
M. De Pasquale (UCL-MSSL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB), V. D'Elia (ASDC), P. A. Evans (U Leicester), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), C. B. Markwardt (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), C. J. Saxton (UCL-MSSL), M. H. Siegel (PSU), C. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team:
At 20:28:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110520A (trigger=453747). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 134.375, +56.402 which is
```
   RA(J2000)  =  08h 57m 30s
   Dec(J2000) = +56d 24' 06"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a FRED-like pulse with a duration of about 30 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 20:30:28.3 UT, 100.1 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 134.34208, 56.42720 which is equivalent to:
```
   RA(J2000)  = 08h 57m 22.10s
   Dec(J2000) = +56d 25' 37.9"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 112 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.73 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.5 (+1.48/-1.31) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 103 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 none of the XRT error circle. 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 0.03.
Burst Advocate for this burst is M. De Pasquale (mdp 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:     Fri 20 May 11 20:53:26 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.320d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.414d {+56d 24' 52"} (J2000)
POINT_ROLL:      270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  74596.46 SOD {20:43:16.46} UT,   868.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.528
N_STARS:         172
X_OFFSET:        1 [pixels]
Y_OFFSET:        345 [pixels]
X_MAX:           1440 [pixels]
Y_MAX:           1784 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00453747000msufc0868.fits
SUN_POSTN:        57.29d {+03h 49m 10s}  +20.04d {+20d 02' 27"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.96d {+18h 59m 49s}  -20.90d {-20d 53' 48"}
MOON_DIST:       138.33 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.67, 39.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.36 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:53:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.320d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.414d {+56d 24' 52"} (J2000)
POINT_ROLL:      270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  74596.46 SOD {20:43:16.46} UT,   868.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.528
N_STARS:         172
X_OFFSET:        1 [pixels]
Y_OFFSET:        345 [pixels]
X_MAX:           1440 [pixels]
Y_MAX:           1784 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00453747000msufc0868.fits
SUN_POSTN:        57.29d {+03h 49m 10s}  +20.04d {+20d 02' 27"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.96d {+18h 59m 50s}  -20.90d {-20d 53' 46"}
MOON_DIST:       138.33 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.67, 39.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.36 [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:     Fri 20 May 11 20:54:10 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.320d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.414d {+56d 24' 52"} (J2000)
ROLL:            270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  74596.46 SOD {20:43:16.46} UT,   868.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327617003
X_OFFSET:        560 [pixels]
Y_OFFSET:        904 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       720
Y_GRB_POS:       1064
BINNING_INDEX:   1
IM_URL:          sw00453747000msuni0875.fits
SUN_POSTN:        57.29d {+03h 49m 10s}  +20.04d {+20d 02' 27"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.96d {+18h 59m 51s}  -20.90d {-20d 53' 43"}
MOON_DIST:       138.33 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.67, 39.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.36 [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:     Fri 20 May 11 20:54:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     453747,   Seg_Num: 0
POINT_RA:        134.320d {+08h 57m 17s} (J2000)
POINT_DEC:       +56.414d {+56d 24' 52"} (J2000)
ROLL:            270.893d
IMG_START_DATE:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  74596.46 SOD {20:43:16.46} UT,   868.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     327617003
X_OFFSET:        560 [pixels]
Y_OFFSET:        904 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       720
Y_GRB_POS:       1064
BINNING_INDEX:   1
IM_URL:          sw00453747000msuni0875.fits
SUN_POSTN:        57.29d {+03h 49m 11s}  +20.04d {+20d 02' 28"}
SUN_DIST:         66.41 [deg]   Sun_angle= -5.1 [hr] (East of Sun)
MOON_POSTN:      284.97d {+18h 59m 52s}  -20.90d {-20d 53' 41"}
MOON_DIST:       138.33 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.67, 39.55 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.10, 37.36 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 20 May 11 20:54:36 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     453747,   Seg_Num: 0
GRB_RA:          134.3403d {+08h 57m 21.67s} (J2000),
                 134.5542d {+08h 58m 13.01s} (current),
                 133.3963d {+08h 53m 35.10s} (1950)
GRB_DEC:         +56.4269d {+56d 25' 36.8"} (J2000),
                 +56.3825d {+56d 22' 57.0"} (current),
                 +56.6198d {+56d 37' 11.4"} (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:  15701 TJD;   140 DOY;   11/05/20
IMG_START_TIME:  73896.00 SOD {20:31:36.00} UT,   167.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        57.29d {+03h 49m 11s}  +20.04d {+20d 02' 28"}
SUN_DIST:         66.42 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      284.97d {+18h 59m 52s}  -20.89d {-20d 53' 41"}
MOON_DIST:       138.31 [deg]
MOON_ILLUM:      86 [%]
GAL_COORDS:      160.65, 39.56 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.10, 37.38 [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 Circular #12021
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
O. Gres, K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Chuvalaev Irkutsk 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 Ural(Kaurovka) was pointed to the GRB110520A 53 sec after GRB time and 23 sec after the trigger at 2011-05-20 20:29:41.097 UT. On our first (10s exposure) set we haven`t found optical transient within SWIFT error-box (ra=08 57 31 dec=+56 23 59 r=0.050000). The our unfilterd 5-sigma upper limit has been about 17.0 mag
MASTER II robotic telescope in Tunka(Siberia) also pointed to this GRB, 28 sec after trigger time in two polarizations. But the Sun was too high (only 5 deg. below horizont) and upper limit is about 15.0 mag on the bosh first 10 sec sets.
This message may be cited.
GCN Circular #12022
Klotz A. (CESR-OMP), Gendre B. (ASDC), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 110520A detected by SWIFT (trigger 453747) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France.
The observations started 45s after the GRB trigger (15s after the notice). The elevation of the field decreased from 51 degrees above horizon and weather conditions were good.
The date of trigger : t0 = 2011-05-20T20:28:48
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 error box with a limiting magnitude of: t0+44.9s to t0+104.9s : R > 17.3
The second image is 30.0s exposure in tracking mode: t0+119.6s to t0+149.6s : R > 18.5
We co-added a series of exposures: t0+119.6s to t0+310.9s : R > 19.0
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular #12023
R.J. Smith (Liverpool), A Melandri (INAF-OAB), N. Tanvir (Leicester), C.G. Mundell (Liverpool) report on behalf of a larger collaboration:
The 2-m Liverpool Telescope followed up GRB110520A (SWIFT trigger 453747; De Pasquale et al. GCN 12020) and obtained a 1200sec r' integration centred 1.36 hours after the SWIFT burst time. We do not detect any optical transient to a 3 sigma detection limit of R > 23.5, based on comparison to nearby USNO-B catalogue stars.
No further observations are planned.
This message may be cited.
GCN Circular #12024
A. LaCluyze, M. Maturi, K. Ivarsen, J. Haislip, D. Reichart, J. Moore, A. Trotter, A. Foster, R.Egger, A. Oza, E. Speckhard, J. A. Crain, and M. Nysewanderreport:
Skynet observed the Swift/XRT localization of GRB 110520A (Swift trigger#453747) with the Dolomites Astronomical Observatory located at the Carlo Magno Hotel Spa Resort in Italy. Due to local twilight, observations in SDSS g',r',i' and z' did not begin until ~25 minutes after the trigger.
We do not detect an optical transit within the Swift error circle in any filter. Our earliest time photometry yields the following 3-sigma limiting magnitudes: g' 17.8 (mean time of 26.78 minutes after trigger), r' 19.7 (mean time of 31.32 minutes after trigger, two combined exposures), i' 18.5 (mean time of 37.10 minutes after trigger, two combined exposures), z' 17.8 (mean time of 41.95 minutes after trigger) based on comparison ~6 nearby SDSS sources.
This message may be cited.
GCN Circular #12025
S. Schulze (U. Iceland), D. Xu (WIS), D. Malesani (DARK/NBI), P. =20 Jakobsson (U. Iceland), S. Asadi, A. Barekat, L. Guaita, I. A. Gumus, S. Lindgren, J. =20 Lindkvist, K. Migotto, A. Razza, T. Str=F6m, F. Taddia, G. Olofsson (Stockholm Observatory), report on =20 behalf of a larger collaboration:
We observed the field of GRB 110520A (De Pasquale et al., GCN 12020) =20 with the Nordic Opitcal Telescope (NOT) equipped with ALFOSC. We obtained 3x600 s R-band and 6x300 s I-band images. Observations started at 21:19:16.9 UT on May 20 (i.e., 0.8414 hr after the burst).
An optical source is clearly detected in each of the stacked R-band and I-band images at coordinates
```
RA(J2000)  =3D 08:57:21.84
Dec(J2000) =3D +56:25:40.2
Error-radius: ~0.1 arcsec
```
which is 2.7 arcsec away of the XRT position center reported at http://www.swift.ac.uk/sper/index.php.
This source has R~23.7 mag at a median time 1.118 hrs post-burst, calibrated with the #1464-0205280 star (R1=3D18.97, R2=3D18.92) in the USNO B1 catalog. At the moment our data does not allow to test for variability of the source.
GCN Circular #12026
A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), R. Canning (U. Cambridge), F. Riddick (ING) report on behalf of a larger collaboration:
"We observed the location of GRB 110520A (GCN 12020) using the William Herschel Telescope equipped with LIRIS. Observations began at 22:21 UT on 20 May 2011, 1.9 hours after the burst, and were conducted in the zYJHK bands. We do not find any sources with the XRT localization of GRB 110520A, down to preliminary limiting magnitudes of z>22.1, J>20.8, H>20.1, K>19.5, calibrated against SDSS and 2MASS observations of the field.
We do note two sources which lie just outside the XRT localization. The object noted by Schulze et al. (GCN 12025) is very weakly detected in our images, while an additional object at
```
RA(J2000) 08:57:22.02 
DEC(J2000) 56:25:35.31 
+/- 0.2"
```
is also present in all our observed bands, but is offset ~4" from the XRT location. At this stage we cannot ascertain if either of these sources is a plausible afterglow for GRB 110520A."
GCN Circular #12027
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1918 s of XRT Photon Counting mode data and 2 UVOT images for GRB 110520A, 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 = 134.34074, +56.42735 which is equivalent to:
```
RA (J2000): 08h 57m 21.78s
Dec (J2000): +56d 25' 38.5"
```
with an uncertainty of 1.5 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 #12028
A.P. Beardmore (U. Leicester) and M. De Pasquale (UCL-MSSL) report on behalf of the Swift-XRT team:
We have analysed 11 ks of XRT data for GRB 110520A (De Pasquale et al. GCN Circ. 12020), from 84 s to 25.2 ks after the BAT trigger. The data comprise 74 s in Windowed Timing (WT) mode (the first 9 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 Osborne et al. (GCN. Circ 12027).
The light curve initially follows a power-law decline with decay index alpha=2.0, then shows a small flare from T+137 s to T+516 s, reaching a peak count rate of 12 c/s at T+254 s, after which it decays with an index of 1.42 (+0.12, -0.11).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.77 (+/-0.17). The best-fitting absorption column is 2.9 (+/-0.6) x 10^21 cm^-2, in excess of the Galactic value of 2.7 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 5.0 x 10^-11 (7.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.9 (+/-0.6) x 10^21 cm^-2
Galactic foreground: 2.7 x 10^20 cm^-2
Excess significance: 7.4 sigma
Photon index:	     1.77 (+/-0.17)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00453747.
This circular is an official product of the Swift-XRT team.
GCN Circular #12029
J. Gorosabel (IAA-CSIC, Granada), R. Barrena (IAC, Tenerife), A.J. Castro-Tirado (IAA-CSIC, Granada), A. de Ugarte Postigo (DARK/NBI, Copenhagen), D. Malesani (DARK/NBI, Copenhagen), report on behalf of a larger collaboration:
"We have observed the field of GRB 110520A (De Pasquale et al., GCNC 12020) with the 82cm IAC80 telescope located at the Observatory of Teide, Tenerife. The observations were carried out in the I band on May 20.87397-20.94593 UT (0.495-2.222 hours after the GRB). No object is detected within the enhanced XRT error circle (Osborne et al. GCN 12027) down to I~22.1 (calibration based on USNO-B1). The objects noted by Schulze et al. (GCNC 12025) and Levan et al. (GCNC 12026) are not present in our co-added image."
GCN Circular #12030
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), M. De Pasquale (UCL-MSSL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 110520A (trigger #453747) (De Pasquale, et al., GCN Circ. 12020). The BAT ground-calculated position is RA, Dec = 134.363, 56.418 deg which is
```
   RA(J2000)  =  08h 57m 27.1s 
   Dec(J2000) = +56d 25' 04.9" 
```
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 69%.
The mask-weighted light curve shows a single FRED peak starting at ~T-2 sec, peaking at ~T+4 sec, and ending at ~T+40 sec. T90 (15-350 keV) is 15.7 +- 1.8 sec (estimated error including systematics).
The time-averaged spectrum from T-1.2 to T+16.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.13 +- 0.10. 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+4.15 sec in the 15-150 keV band is 1.1 +- 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/453747/BA/
GCN Circular #12032
M. De Pasquale (MSSL-UCL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 110520A 104 s after the BAT trigger (De Pasquale et al., GCN Circ. 12020). No optical afterglow consistent with the enhanced XRT position (Osborne et al., GCN Circ. 12027) or at the position of the NOT and WHT sources (Schulze et al., GCN Circ 12025; Levan et al. GCN Circ 12026) is detected in the initial and in the summed 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           104          253          147 	>21.1
u_FC               316          565          246 	>20.4
white              104        30973         3040 	>22.9
v                  645        23608         2083 	>21.0
b                  571        36751         2946 	>22.1
u                  316        42529         3178 	>21.8
w1                 694        41871         2965 	>21.8
m2                 842        40964         2262 	>21.8
w2                 621        19418         1911 	>22.0
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #12037
D. Xu (WIS), S. Schulze, P. Jakobsson (U. Iceland), T. Pursimo (NOT), report on behalf of a larger collaboration:
We continued to observe the field of GRB 110520A (De Pasquale et al., GCN 12020) with the Nordic Opitcal Telescope (NOT) equipped with ALFOSC. We obtained 6x300 s R-band images, starting at 23:02:40.4 UT on May 21 (i.e., 26.565 hrs after the burst).
There was nothing visible within the enhanced XRT error circle (Osborne et al., GCN 12027). The optical source identified in our previous imaging (Schulze et al., GCN 12025) is ~1.9" northeast away of the center of the enhanced XRT error circle, which has a radius of 1.5" (90% C.L.). The source is still point-like and has R=23.7+/-0.1 mag, same as our previous measurement.
The optical source noted by Levan et al. (GCN 12026) was clearly detected in our previous imaging. It was largely point-like and had R=23.9+/-0.1 mag, calibrated with the #1464-0205280 star (R1=18.97, R2=18.92) in the USNO B1 catalog. Now it has become extended (about 3.5" southeast away of the center of the enhanced XRT error circle) and decayed to R=24.5+/-0.2 mag.
GCN Report 335.1
GCN_Report 335.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_335_1.pdf by M. De Pasquale at MSSL-UCL titled: "Final Report on Swift GRB 110520A"

Back to JG's homepage

Jochen Greiner, last update: 22-May-2011 [Disclaimer]