Gamma-ray Burst 110503A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 17:36:04 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     452685,   Seg_Num: 0
GRB_RA:          132.800d {+08h 51m 12s} (J2000),
                 133.005d {+08h 52m 01s} (current),
                 131.893d {+08h 47m 34s} (1950)
GRB_DEC:         +52.216d {+52d 12' 56"} (J2000),
                 +52.173d {+52d 10' 22"} (current),
                 +52.403d {+52d 24' 11"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       15649 [cnts]    Image_Peak=1256 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   151     E_range: 25-100 keV
BKG_INTEN:       44331 [cnts]
BKG_TIME:        63329.08 SOD {17:35:29.08} UT
BKG_DUR:         8 [sec]
GRB_DATE:        15684 TJD;   123 DOY;   11/05/03
GRB_TIME:        63345.53 SOD {17:35:45.53} UT
GRB_PHI:          23.52 [deg]
GRB_THETA:        48.66 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     134.02 [sigma]
IMAGE_SIGNIF:    20.40 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +7  +0  +0 -18  +0 
SUN_POSTN:        40.49d {+02h 41m 58s}  +15.72d {+15d 43' 19"}
SUN_DIST:         79.16 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.64d {+02h 58m 34s}  +20.15d {+20d 09' 06"}
MOON_DIST:        73.23 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.20, 39.24 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      119.80, 33.11 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 359.60,-14.67 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Tue 03 May 11 17:36:25 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    6170,   Sub_Num: 0
GRB_INTEN:      9.47 [sigma]   
GRB_TIME:       63341.96 SOD {17:35:41.96} UT
GRB_DATE:       15684 TJD;   123 DOY;   11/05/03
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(4.0<100sec) coincident with the SWIFT_BAT event (trignum=452685).
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:
+ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2011-05/2011-05-03T17-35-41.7234-22720-00007-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 17:43:07 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     14532607,   Seg_Num: 0
GRB_RA:          132.800d {+08h 51m 12s} (J2000),
                 133.005d {+08h 52m 01s} (current),
                 131.893d {+08h 47m 34s} (1950)
GRB_DEC:         +52.216d {+52d 12' 56"} (J2000),
                 +52.173d {+52d 10' 22"} (current),
                 +52.403d {+52d 24' 11"} (1950)
GRB_DATE:        15684 TJD;   123 DOY;   11/05/03
GRB_TIME:        63345.53 SOD {17:35:45.53} UT
TRIGGER_INDEX:   151
GRB_PHI:          23.52 [deg]
GRB_THETA:        48.66 [deg]
DELTA_TIME:      3646.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    0.00 [sigma]
LC_URL:          sw00452685000msb.lc
SUN_POSTN:        40.50d {+02h 41m 59s}  +15.72d {+15d 43' 24"}
SUN_DIST:         79.15 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.70d {+02h 58m 49s}  +20.16d {+20d 09' 52"}
MOON_DIST:        73.18 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.20, 39.24 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      119.80, 33.11 [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 = 359.60,-14.67 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 17:37:52 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     452685,   Seg_Num: 0
GRB_RA:          132.7778d {+08h 51m 06.67s} (J2000),
                 132.9826d {+08h 51m 55.82s} (current),
                 131.8710d {+08h 47m 29.03s} (1950)
GRB_DEC:         +52.2067d {+52d 12' 24.1"} (J2000),
                 +52.1638d {+52d 09' 49.5"} (current),
                 +52.3942d {+52d 23' 38.9"} (1950)
GRB_ERROR:       5.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       2.05e-09 [erg/cm2/sec]
GRB_SIGNIF:      8.77 [sigma]
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63439.16 SOD {17:37:19.16} UT,   93.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.62 237.22 261.39 243.51
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        40.49d {+02h 41m 58s}  +15.72d {+15d 43' 20"}
SUN_DIST:         79.14 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.66d {+02h 58m 38s}  +20.15d {+20d 09' 17"}
MOON_DIST:        73.21 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.22, 39.22 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.79, 33.10 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.97 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 17:38:02 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     452685,   Seg_Num: 0
GRB_RA:          132.7778d {+08h 51m 06.6s} (J2000),
                 132.9826d {+08h 51m 55.8s} (current),
                 131.8710d {+08h 47m 29.0s} (1950)
GRB_DEC:         +52.2067d {+52d 12' 24.1"} (J2000),
                 +52.1638d {+52d 09' 49.5"} (current),
                 +52.3942d {+52d 23' 38.9"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       77 [cnts]
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63439.16 SOD {17:37:19.16} UT,   93.6 [sec] since BAT Trigger Time
CENTROID_X:      330.81,  raw= 331  [pixels]
CENTROID_Y:      328.35,  raw= 328  [pixels]
ROLL:            281.55 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   71.55
GRB_POS_XRT_Z:   67.20
IMAGE_URL:       sw00452685000msxps_rw.img
SUN_POSTN:        40.49d {+02h 41m 58s}  +15.72d {+15d 43' 20"}
SUN_DIST:         79.14 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.66d {+02h 58m 38s}  +20.16d {+20d 09' 19"}
MOON_DIST:        73.20 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.22, 39.22 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.79, 33.10 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 17:38:13 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     452685,   Seg_Num: 0
GRB_RA:          132.7778d {+08h 51m 06.6s} (J2000),
                 132.9826d {+08h 51m 55.8s} (current),
                 131.8710d {+08h 47m 29.0s} (1950)
GRB_DEC:         +52.2067d {+52d 12' 24.1"} (J2000),
                 +52.1638d {+52d 09' 49.5"} (current),
                 +52.3942d {+52d 23' 38.9"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       77 [cnts]
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63439.16 SOD {17:37:19.16} UT,   93.6 [sec] since BAT Trigger Time
CENTROID_X:      330.81,  raw= 331  [pixels]
CENTROID_Y:      328.35,  raw= 328  [pixels]
ROLL:            281.55 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   71.55
GRB_POS_XRT_Z:   67.20
IMAGE_URL:       sw00452685000msxps_rw.img
SUN_POSTN:        40.49d {+02h 41m 58s}  +15.72d {+15d 43' 20"}
SUN_DIST:         79.14 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.66d {+02h 58m 38s}  +20.16d {+20d 09' 20"}
MOON_DIST:        73.20 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.22, 39.22 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.79, 33.10 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 17:56:39 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:        132.752d {+08h 51m 00s} (J2000)
POINT_DEC:       +52.229d {+52d 13' 44"} (J2000)
POINT_ROLL:      281.546d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63557.73 SOD {17:39:17.73} UT,   212.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.310
N_STARS:         23
X_OFFSET:        252 [pixels]
Y_OFFSET:        619 [pixels]
X_MAX:           1211 [pixels]
Y_MAX:           1578 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    6
SL_URL:          sw00452685000msufc0212.fits
SUN_POSTN:        40.50d {+02h 42m 01s}  +15.73d {+15d 43' 34"}
SUN_DIST:         79.11 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.82d {+02h 59m 18s}  +20.19d {+20d 11' 20"}
MOON_DIST:        73.06 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.19, 39.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.76, 33.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 17:57:01 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:        132.752d {+08h 51m 00s} (J2000)
POINT_DEC:       +52.229d {+52d 13' 44"} (J2000)
POINT_ROLL:      281.546d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63557.73 SOD {17:39:17.73} UT,   212.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.310
N_STARS:         23
X_OFFSET:        252 [pixels]
Y_OFFSET:        619 [pixels]
X_MAX:           1211 [pixels]
Y_MAX:           1578 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    6
SL_URL:          sw00452685000msufc0212.fits
SUN_POSTN:        40.50d {+02h 42m 01s}  +15.73d {+15d 43' 34"}
SUN_DIST:         79.11 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.83d {+02h 59m 18s}  +20.19d {+20d 11' 22"}
MOON_DIST:        73.06 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.19, 39.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.76, 33.12 [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:     Tue 03 May 11 17:58:00 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:        132.752d {+08h 51m 00s} (J2000)
POINT_DEC:       +52.229d {+52d 13' 44"} (J2000)
ROLL:            281.546d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63557.73 SOD {17:39:17.73} UT,   212.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     326137164
X_OFFSET:        571 [pixels]
Y_OFFSET:        938 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       731
Y_GRB_POS:       1098
BINNING_INDEX:   1
IM_URL:          sw00452685000msuni0219.fits
SUN_POSTN:        40.51d {+02h 42m 01s}  +15.73d {+15d 43' 35"}
SUN_DIST:         79.11 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.83d {+02h 59m 20s}  +20.19d {+20d 11' 29"}
MOON_DIST:        73.05 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.19, 39.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.76, 33.12 [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:     Tue 03 May 11 17:58:18 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:        132.752d {+08h 51m 00s} (J2000)
POINT_DEC:       +52.229d {+52d 13' 44"} (J2000)
ROLL:            281.546d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63557.73 SOD {17:39:17.73} UT,   212.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     326137164
X_OFFSET:        571 [pixels]
Y_OFFSET:        938 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       731
Y_GRB_POS:       1098
BINNING_INDEX:   1
IM_URL:          sw00452685000msuni0219.fits
SUN_POSTN:        40.51d {+02h 42m 01s}  +15.73d {+15d 43' 35"}
SUN_DIST:         79.11 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.84d {+02h 59m 21s}  +20.19d {+20d 11' 31"}
MOON_DIST:        73.05 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.19, 39.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.76, 33.12 [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 #11991
M. Stamatikos (OSU/NASA/GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), O. M. Littlejohns (U Leicester), V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), P. T. O\'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), M. H. Siegel (PSU), R. L. C. Starling (U Leicester), C. A. Swenson (PSU), E. Troja (NASA/GSFC/ORAU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team:
At 17:35:45 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110503A (trigger=452685). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 132.800, +52.216 which is
```
   RA(J2000)  =  08h 51m 12s
   Dec(J2000) = +52d 12' 56"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single structure with a duration of about 10 sec. The peak count rate was ~17,000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 17:37:19.2 UT, 93.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 132.7778, +52.2067 which is equivalent to:
```
   RA(J2000)  = 08h 51m 06.67s
   Dec(J2000) = +52d 12' 24.1"
```
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This location is 58 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
UVOT took a finding chart exposure of nominal 150.000 seconds with the White filter starting 212 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at
```
  RA(J2000)  =	08:51:06.24 = 132.77598
  DEC(J2000) = +52:12:27.5  =  52.20764
```
with a 90%-confidence error radius of about 1.10 arc sec. This position is 5.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 15.75. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02.
Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 18:02:43 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:        132.752d {+08h 51m 00s} (J2000)
POINT_DEC:       +52.229d {+52d 13' 45"} (J2000)
POINT_ROLL:      281.545d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  64209.48 SOD {17:50:09.48} UT,   864.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.182
N_STARS:         66
X_OFFSET:        12 [pixels]
Y_OFFSET:        379 [pixels]
X_MAX:           1451 [pixels]
Y_MAX:           1818 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00452685000msufc0863.fits
SUN_POSTN:        40.51d {+02h 42m 02s}  +15.73d {+15d 43' 38"}
SUN_DIST:         79.11 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.88d {+02h 59m 30s}  +20.20d {+20d 11' 59"}
MOON_DIST:        73.02 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.19, 39.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.76, 33.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 03 May 11 18:03:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:        132.752d {+08h 51m 00s} (J2000)
POINT_DEC:       +52.229d {+52d 13' 45"} (J2000)
POINT_ROLL:      281.545d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  64209.48 SOD {17:50:09.48} UT,   864.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.182
N_STARS:         66
X_OFFSET:        12 [pixels]
Y_OFFSET:        379 [pixels]
X_MAX:           1451 [pixels]
Y_MAX:           1818 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00452685000msufc0863.fits
SUN_POSTN:        40.51d {+02h 42m 02s}  +15.73d {+15d 43' 39"}
SUN_DIST:         79.11 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.88d {+02h 59m 31s}  +20.20d {+20d 12' 02"}
MOON_DIST:        73.02 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.19, 39.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.76, 33.12 [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:     Tue 03 May 11 18:04:52 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     452685,   Seg_Num: 0
GRB_RA:          132.7747d {+08h 51m 05.92s} (J2000),
                 132.9795d {+08h 51m 55.08s} (current),
                 131.8678d {+08h 47m 28.28s} (1950)
GRB_DEC:         +52.2077d {+52d 12' 27.7"} (J2000),
                 +52.1648d {+52d 09' 53.1"} (current),
                 +52.3952d {+52d 23' 42.5"} (1950)
GRB_ERROR:       2.4 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  64200.00 SOD {17:50:00.00} UT,   854.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        40.51d {+02h 42m 02s}  +15.73d {+15d 43' 40"}
SUN_DIST:         79.13 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.90d {+02h 59m 35s}  +20.20d {+20d 12' 13"}
MOON_DIST:        73.02 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.22, 39.22 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.79, 33.10 [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:     Tue 03 May 11 18:05:34 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:          0.000d {+00h 00m 00s} (J2000)
POINT_DEC:        +0.000d {+00d 00' 00"} (J2000)
ROLL:            52.229d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  64676.63 SOD {17:57:56.63} UT,   1331.1 [sec] since BAT Trigger Time
FILTER:          0, illegal value
EXPOSURE_ID:     65537
X_OFFSET:        911 [pixels]
Y_OFFSET:        1281 [pixels]
WIDTH:           386 [pixels]
HEIGHT:          1063 [pixels]
X_GRB_POS:       0
Y_GRB_POS:       0
BINNING_INDEX:   0
IM_URL:          sw00452685000msuni0870.fits
SUN_POSTN:        40.51d {+02h 42m 02s}  +15.73d {+15d 43' 40"}
SUN_DIST:         42.80 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:       44.90d {+02h 59m 36s}  +20.21d {+20d 12' 18"}
MOON_DIST:        48.18 [deg]
MOON_ILLUM:      0 [%]
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:        WARNING: This Notice was received with 1 (or more) critical values out of range.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 1x1 binning (ie no 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:     Tue 03 May 11 18:05:51 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     452685,   Seg_Num: 0
POINT_RA:          0.000d {+00h 00m 00s} (J2000)
POINT_DEC:        +0.000d {+00d 00' 00"} (J2000)
ROLL:            52.229d
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  64676.63 SOD {17:57:56.63} UT,   1331.1 [sec] since BAT Trigger Time
FILTER:          0, illegal value
EXPOSURE_ID:     65537
X_OFFSET:        911 [pixels]
Y_OFFSET:        1281 [pixels]
WIDTH:           386 [pixels]
HEIGHT:          1063 [pixels]
X_GRB_POS:       0
Y_GRB_POS:       0
BINNING_INDEX:   0
IM_URL:          sw00452685000msuni0870.fits
SUN_POSTN:        40.51d {+02h 42m 03s}  +15.73d {+15d 43' 41"}
SUN_DIST:         42.80 [deg]   Sun_angle= 2.7 [hr] (West of Sun)
MOON_POSTN:       44.90d {+02h 59m 37s}  +20.21d {+20d 12' 20"}
MOON_DIST:        48.18 [deg]
MOON_ILLUM:      0 [%]
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:        WARNING: This Notice was received with 1 (or more) critical values out of range.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 1x1 binning (ie no compression).  
COMMENTS:        All 4 attachments are included.  
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:     Tue 03 May 11 18:08:11 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     452685,   Seg_Num: 0
GRB_RA:          132.7759d {+08h 51m 06.21s} (J2000),
                 132.9807d {+08h 51m 55.37s} (current),
                 131.8690d {+08h 47m 28.57s} (1950)
GRB_DEC:         +52.2077d {+52d 12' 27.7"} (J2000),
                 +52.1648d {+52d 09' 53.1"} (current),
                 +52.3952d {+52d 23' 42.5"} (1950)
GRB_ERROR:       0.7 [arcsec radius, statistical only]
GRB_MAG:         15.81 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  15684 TJD;   123 DOY;   11/05/03
IMG_START_TIME:  63562.00 SOD {17:39:22.00} UT,   216.5 [sec] since BAT Trigger Time
SUN_POSTN:        40.51d {+02h 42m 03s}  +15.73d {+15d 43' 42"}
SUN_DIST:         79.13 [deg]   Sun_angle= -6.2 [hr] (East of Sun)
MOON_POSTN:       44.92d {+02h 59m 42s}  +20.21d {+20d 12' 35"}
MOON_DIST:        73.00 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      166.22, 39.22 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      119.79, 33.10 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 5.4 arcsec from the XRT position.

GCN Circular #11992
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 995 s of XRT Photon Counting mode data and 1 UVOT images for GRB 110503A, 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 = 132.77598, +52.20753 which is equivalent to:
```
RA (J2000): 08h 51m 6.24s
Dec (J2000): +52d 12' 27.1"
```
with an uncertainty of 1.8 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 #11993
A. de Ugarte Postigo (DARK/NBI), A.J. Castro-Tirado, J.C. Tello (IAA-CSIC), A. Cabrera Lavers, D. Reverte (GTC) report on behalf of a larger collaboration:
We have observed the afterglow of GRB 110503A (Stamatikos et al. GCNC11991) using OSIRIS at the 10.4m GTC telescope (La Palma, Spain). Observations consisted on 2x900s using the R500B grating, starting at 21:36UT (4.0h after the burst). In a preliminary analysis, using archival calibrations, we detect a high signal to noise ratio continuum with absorption features that include SiIV, SiII, CIV, FeII, AlII, AlIII, ZnII, MgII and MgI at a common redshift of z=1.613, which we identify as the redshift of the afterglow.
GCN Circular #11994
G. Leloudas (DARK/NBI), D. Xu (WIS), A. de Ugarte Postigo (DARK/NBI), P. Jakobsson (U. Iceland), L. Guaita, A. Sandberg (OKC/Stockholm), report on behalf of a larger collaboration.
We used the Nordic Optical Telescope (La Palma, Spain) equipped with MOSCA to observe GRB 110503A (Stamatikos et al., GCN 11991). Observations were conducted in the UBVRI filters starting at 21:18 UT (222.3 min after the BAT trigger). The exposure times were 600, 300, 300, 300 and 400 s respectively.
The afterglow is well detected in all filters at a position consistent with the UVOT observations (Stamatikos et al., GCN 11991).
Photometry, using stars 1422-0232263 and 1422-0232264 of the USNO B1.0 catalog as comparison, gives B ~ 19.7 and R ~ 19.3.
GCN Circular #11995
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-124 to T+689 sec from recent telemetry downlinks, we report further analysis of BAT GRB 110503A (trigger #452685) (Stamatikos, et al., GCN Circ. 11991). The BAT ground-calculated position is RA, Dec = 132.799, 52.211 deg which is
```
 
   RA(J2000)  =  08h 51m 11.8s  
   Dec(J2000) = +52d 12' 40.4"  
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 11%.
The mask-weighted light curve shows a single FRED-like peak starting at ~T-4 sec, peaking at ~T+0.2 sec, and returning to background around T+20 sec. There there is a long low-level emission from T+50 to T+200 sec. T90 (15-350 keV) is 10.0 +- 3.5 sec (estimated error including systematics).
The time-averaged spectrum from T-6.6 to T+16.3 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.88 +- 0.25, and Epeak of 133 +- 54 keV (chi squared 84.4 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.00 +- 0.04 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T-0.12 sec in the 15-150 keV band is 29.7 +- 1.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.35 +- 0.06 (chi squared 95.5 for 57 d.o.f.). 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/452685/BA/
GCN Circular #11996
D. A. Kann, S. Schmidl, C. Hoegner, B. Stecklum, S. Schumann and M. Hartmann (TLS Tautenburg) report:
We observed the afterglow of GRB 110503A (M. Stamatikos et al., GCN 11991, G. Leloudas et al., GCN 11994) at z=1.613 (A. de Ugarte Postigo et al., GCN 11993) with the 2m/1.34m Schmidt telescope of the Thueringer Landessternwarte Tautenburg under excellent observing conditions (low airmass, good transparency and seeing) starting during dawn at 0.098715 days after the GRB.
Observations consisted of 3 x 180 s each in Z, Ic, Rc, V, B, followed by 3 x 300 s each in Z, Ic, Rc, V, B. The afterglow is detected on the single images.
Assuming the USNO-B1.0 1421-0227752 star at RA = 08:51:10.01 (132.791692) Dec. = +52:11:04.75 (+52.184653) has R = 16.91 (mean of R1 and R2 mags, 0.06 mags difference), we find for two Rc band observations:
```
 
t (days after trigger) = 0.1187616, Rc = 19.07 +/- 0.03 
t (days after trigger) = 0.1750347, Rc = 19.51 +/- 0.04 
```
Errors are statistical only.
Observations are continuing as weather permits with 600 s exposures in all five colors.
This message may be cited.
GCN Circular #11997
P. D'Avanzo (INAF/OAB), V. D'Elia (ASI/ASDC), L. Di Fabrizio, A. Gurtu (INAF/TNG), report on behalf of a larger collaboration:
We observed the optical afterglow of GRB 110503A (Stamatikos et al. GCN 11991) with the Italian TNG located in La Palma, equipped with the DOLORES camera in spectroscopic mode. The optical afterglow (Leloudas et al. GCN 11994; Kann et al. GCN 11996) is clearly detected in the unfiltered acquisition image, with a magnitude R~19.5 at at t-t0=4.85 hours (using the calibration of Kann et al. GCN 11996).
A low-resolution spectrum was taken at a mean time t-t0=5.25 hours. The adopted grism was LR-B, covering the wavelength range 3900-8200 AA with a resolution of R~600. Using a preliminary wavelength calibration we clearly detect several absorption features, including CIV, SiII, AlIII, AlII, MgII and MgI, all at a common redshift z=1.61, in agreement with the value reported by de Ugarte Postigo et al. (GCN 11993). At the same redshift we also detect the fine structure line SiII*1533. This absorption feature is likely produced in the GRB host, further supporting the statement that z=1.61 is the afterglow redshift.
GCN Circular #11998
A. N. Morgan, and J. S. Bloom (UC Berkeley) report:
We observed the field of GRB 110503A (Stamatikos et al., GCN 11991) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona under poor sky conditions. Observations began at 2011-05-04 02:46:35 UT, ~9.2 hours after the Swift Trigger. In mosaics (effective exposure time of 1.28 hours) taken simultaneously in the J and H filters, we marginally detect a source at the optical afterglow location (Stamatikos et al., GCN 11991; Leloudas et al., GCN 11994; Kann et al., GCN 11996). Our preliminary Ks band reduction is corrupted.
The preliminary photometry yields:
```
post burst
t_mid (hr) exp.(hr) filt  mag    m_err
10.2       1.28     J     18.19  0.26
10.2       1.28     H     17.86  0.36
```
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 #11999
K.L. Page (U. Leicester) and M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift-XRT team:
We have analysed 8.2 ks of XRT data for GRB 110503A (Stamatikos et al. GCN Circ. 11991), from 166 s to 28.4 ks after the BAT trigger. The data comprise 1.1 ks in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 11992).
The light curve can be modelled with a power-law decay with a decay index of alpha=1.059 (+/-0.013).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.86 (+/-0.04). The best-fitting absorption column is 2.2 (+/-0.6) x 10^21 cm^-2, at a redshift of 1.613, in addition to the Galactic value of 2.6 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.01 (+/-0.08) and a best-fitting absorption column of 2.4 (+/-1.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Galactic foreground: 2.6 x 10^20 cm^-2
Intrinsic column:    2.4 (+/-1.0) x 10^21 cm^-2 at z=1.613
Photon index:	     2.01 (+/-0.08)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00452685.
This circular is an official product of the Swift-XRT team.
GCN Circular #12000
S. R. Oates (MSSL-UCL) & M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift-UVOT team
The Swift/UVOT began settled observations of the field of GRB 110503A 212s after the trigger (Stamatikos et al., GCN Circ. 11991). We detect a fading source in all filters at a refined position of RA(J2000), DEC(J2000)= 132.77588 deg,52.20767 deg. This is equivalent to:
```
     RA (J2000)   8:51:06.21
    Dec (J2000)  52:12:27.6
```
with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence). This is consistent with the UVOT position reported in Stamatikos et al. (GCN Circ. 11991) and with the enhanced position of the X-ray afterglow (Goad et al., GCN Circ. 11992).
Preliminary magnitudes using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the finding chart (FC) and summed exposures at the location of the optical afterglow are:
```
Filter  T_start(s)  T_stop(s)   Exp(s)       Mag
#####################################################
wh (FC)    212        362        147     15.82 +/- 0.02
wh         864        1014       147     17.09 +/- 0.03
v          368        388        20      16.23 +/- 0.14
b          469        488        19      16.79 +/- 0.10      
u          445        464        19      15.87 +/- 0.09
uvw1       419        438        19      16.15 +/- 0.15
uvm2       394        414        19      17.27 +/- 0.32
uvw2       519        539        19      17.72 +/- 0.31
#####################################################
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #12001
Adria C. Updike (NASA/GSFC), D. A. Kann (TLS Tautenburg), Dieter H. Hartmann (Clemson University), and Ken Rumstay (Valdosta State University) report:
We observed the field of GRB 110503A (M. Stamatikos et al., GCN 11991) with the SARA-North 0.9m telescope located at KPNO under good conditions beginning about 13 hours after the trigger and continuing for half an hour. We detect the afterglow in each 120 sec exposure. In a stacked 20 min image with mean time 0.5484375 days after the trigger, we detect the afterglow at R = 20.20 +/- 0.07 using the SDSS-derived magnitude of the comparison star given by Kann et al. (GCN 11996). Further observations are planned.
The comparison star utilized by Kann et al. has the following SDSS magnitudes (transformation from Lupton (2005) and Jordi et al. (2006):
```
u = 21.214
g = 18.546
r = 17.166
i = 16.485
z = 16.111
```
and Vega magnitudes:
```
U = 20.431
B = 19.193
V = 17.802
R = 16.819
I = 15.942
Z = 15.562
```
GCN Circular #12002
A. de Ugarte Postigo (DARK/NBI), G. Petitpas (SMA) and S. Martin (ESO) report on behalf of a larger collaboration:
We have observed the afterglow of GRB 110503A (Stamatikos et al. GCNC11991) with the Submillimeter Array (SMA, Hawaii, U.S.A.). Observations were performed at 217GHz (1.4 mm) using 5 antennas under unstable weather conditions (optical depth at 225 GHz ~0.25, humidity ~50%). The GRB field was observed for 268 minutes (on-source), starting at 1:15 UT, with mean epoch on 4 May at 5:36 UT, 12.0 hours after the burst. We do not detect any significant flux at the position of the optical afterglow, imposing a 3-sigma detection limit of 5.1 mJy.
GCN Circular #12003
Dale A. Frail (NRAO), Ashley Zauderer (Harvard), and Edo Berger (Harvard) report on behalf of a larger collaboration:
We imaged a field toward the Swift burst GRB 110503A (GCN 11991,11995) with the EVLA starting on 2011 May 4.04 (i.e. 7.4 hrs after the burst). The EVLA observed at two frequencies (1 GHz bandwidth each) centered at 19.2 GHz and 24.5 GHz. In a preliminary data analysis we find a unresolved radio source within the UVOT error circle (GCN 12000) with a mean flux density of 160 +/- 15 uJy and a position (J2000) of RA=08:51:06.21, Dec.=+52 12 27.43, with a conservative error of +/-0.05 arcsec.
We caution that these results are only preliminary. Further observations are planned.
GCN Circular #12004
Myungshin Im (CEOU/Seoul National Univ), Hyun-Il Sung (KASI), and Yuji Urata (NCU) on behalf of EAFON
We observed GRB 110503A (Stamatikos et al., GCN 11991) in R-band with a 1.0-m telescope at Mt. Lemmon, Arizona. The observation started at 05-04-03:24:30 UT. We detect the afterglow with a magnitude at R ~ 20.28 +- 0.09 mag (mid-time of ~10.0 hrs after BAT alert) based on the photometry calibration star reported by Updike et al.(GCN 12001).
Further analysis of the data and the follow-up observations of the object is ongoing. We thank the LOAO operator, I.-K. Baek for her assistance with the observation.
GCN Circular #12005
E. Pavlenko (CraO), A. Volnova (SAI MSU), A. Baklanov (CrAO), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We observed the field of GRB 110503A (Stamatikos et al. GCN 11991) with Shajn telescope of CrAO observatory on May. 3 starting (UT) 23:56. We took several frames with exposure of 60s in R-band. The afterglow (Stamatikos et al. GCN 11991) is well detected in each single frame. A preliminary photometry is based on the USNO B1.0 star 1421-0227752 (08:51:10.01 +52:11:04.75) assuming R=16.819 (Updike et al. GCN 12001):
```
T0+         Filter,   Exposure, mag.
(mid, d)               (s)

0.26433    R         60       19.00 +/- 0.08
0.27991    R         60       19.24 +/- 0.18
0.29450    R         60       19.22 +/- 0.08
```
GCN Circular #12008
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
The long GRB 110503A, (Swift/BAT trigger=3D452685: Stamatikos et al., GCN 11991; Sakamoto et.al, GCN 11995) triggered Konus-Wind at T0=3D63341.862s UT (17:35:41.862)
The burst light curve consists of a single pulse with a total duration of ~12 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110503_T63341/
As observed by Konus-Wind the burst had a fluence of (2.6 =B1 0.2)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+2.304 s, of (1.0 =B1 1)x10-5 erg/cm2/s (both in the 20 keV - 5 MeV energy range).
The time-integrated spectrum of the burst (from T0 to T0+10.752 s) is best fitted in the 20 keV - 5 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha =3D -0.98 (-0.08, +0.09), the high energy photon index beta =3D -2.7 (-0.5, +0.2), the peak energy Ep =3D 219(-19, +20) keV, chi2 =3D 69.5/76 dof.
The spectrum at the maximum count rate (measured from T0+1.792 s to T0+2.560 s) can be fitted in the 20 keV - 5 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha =3D -0.44 (-0.16, +0.19), the high energy photon index beta =3D -2.75 (-0.4, +0.3), the peak energy Ep =3D 211(-23, +25) keV, chi2 =3D 55.4/48 dof.
Assuming the afterglow redshift z =3D 1.61 (de Ugarte Postigo et al., GCN 11993; D'Avanzo et al., GCN 11997) and a standard cosmology model with H_0 =3D 71 km/s/Mpc, Omega_M =3D 0.27, Omega_Lambda =3D 0.73, the isotropic energy release E_iso is (1.77 =B1 0.15)x10^53 erg, the peak luminosity L_iso_max is (1.83 =B1 0.18)x10^53 erg/s, and Ep_rest is 570 =B1 50 keV.
All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.
GCN Circular #12009
Eric Broens (Mol, Belgium) and David Boyd (West Challow, Oxfordshire, UK) separately reported to the AAVSO International High Energy Network the following optical observations of GRB 110503A (GCN Circ. #11991, Stamatikos et al.):
E. Broens (VVS WVS, Belgium) reports a detection of GRB 110503A at CR = 19.6 +/- 0.2 on 2011 May 3.921 UT (JD 2455685.421; midpoint of exposures), approximately 4.5 hours after the Swift trigger (GCN Circ. #11991, Stamatikos et al.). Broens obtained 41 frames of 60 seconds exposure in a clear filter using a 0.2-meter f7 SCT telescope with SBIG ST-7MXE CCD camera. An ensemble of three nearby SDSS stars were used as comparisons, with their R-band magnitudes calculated using the Jester et al. (2009, AJ 130, 873) relations. Comparison stars used were: SDSS J085110.53+521301.8 (R = 17.98) and SDSS J085110.02+521104.6 (R=17.20). The measured position of the GRB was:
RA: 08 51 06.3 , Dec: +52 12 26.9
Prior to acquisition of the unfiltered frames, a total of thirty 60-second frames (1800s total) were taken with a Cousins R filter centered at 2011 May 3.895 approximately four hours after the burst. The filtered observations yielded an upper limit of Rc < 18.7.
D. Boyd (West Challow, Oxfordshire, UK) reports V-band optical time series of GRB 110503A obtained using a 0.35-m SCT with a Starlight Express SXVR-H9 CCD camera. A total of 150 60-second frames were obtained, and these were stacked in groups of 30 to obtain five 1800-second integrations. The burst was detected in all frames. The resulting time-series are as follows:
```
2011 May 3.89920 UT	V=19.40 +/- 0.04
2011 May 3.92022 UT	V=19.57 +/- 0.04
2011 May 3.94123 UT	V=19.71 +/- 0.04
2011 May 3.96225 UT	V=19.74 +/- 0.05
2011 May 3.98326 UT	V=19.96 +/- 0.05
```
Magnitudes were obtained using Astrometrica software using UCAC3 for positions and photometry; Boyd reports that magnitudes were obtained using varying ensembles of between 14 and 19 stars per stacked image. Boyd also notes that the coorindates of the GRB on all frames was
RA: 08 51 06.19 , Dec: +52 12 27.3 (J2000)
The AAVSO International High Energy Network was made possible through grants from the Charles Curry Foundation and NASA.
GCN Circular #12010
D. A. Kann, S. Schmidl, B. Stecklum and C. Hoegner (TLS Tautenburg) report:
Observations of GRB 110503A (M. Stamatikos et al., GCN 11991) and its afterglow are continuing at TLS Tautenburg (D. A. Kann et al., GCN 11996). In the first night, we observed for a total of 6 hours, with conditions becoming worse (increasing airmass and passing clouds). 43 detections in BVRIZ were secured.
In the second night, observational conditions were challenging, with passing clouds and high airmass at the time observations could begin. We obtained 3 x 300 s in Rc, 3 x 450 s in V and only a single 450 s B observation. The afterglow is faintly detected in the Rc and V stacks as well as the B image. Using the comparison star of GCN 11996, as calibrated by A. Updike et al. (GCN 12001), we find:
t (days after trigger) = 1.24878, Rc = 21.39 +/- 0.12
We re-observed the afterglow position in the third night under moderate conditions (low airmass, good seeing, but low transparency). We obtained 6 x 600 s in the Rc band. Even in the stack, the afterglow is only faintly detected. We find:
t (days after trigger) = 2.14026, Rc = 22.63 +/- 0.28
Fitting our Rc band data shows a clear break, with alpha_1 = 0.83 +/- 0.03, alpha_2 = 2.3 +/- 0.6 (due to sparse data with large errors), t_b = 1.06 +/- 0.14 days. While both the post-break decay slope as well as the break time are insecure due to sparsity of the data, the data point at 2.14 days lies a complete magnitude under the extrapolation of the early decay, making the existence of a break itself secure.
We propose this is the jet break of the afterglow.
Deeper follow-up with telescopes of larger aperature is highly encouraged.
This message may be cited.
GCN Circular #12011
Klotz A. (CESR-OMP), Gendre B. (ASDC), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 110503A detected by SWIFT (trigger 451901) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France.
The observations started 1.9h after the GRB trigger (trigger occured during daytime). The elevation of the field decreased from 69 degrees above horizon and weather conditions were good.
We detect the candidate couterpart mentioned by Stamatikos et al. 2011 (GCNC 11991) on co-added series of exposures. We used the reference star USNO B1.0 1421-0227752 (08:51:10.01 +52:11:04.75 J2000) described by Kann et al. 2011 (GCNC 11996) assuming R=16.819 (Updike et al. GCN 12001).
```
start   stop   R
1.96h - 2.65h  18.42 +/- 0.15
2.71h - 3.99h  19.11 +/- 0.10
4.04h - 5.33h  19.51 +/- 0.12
5.38h - 7.43h  19.93 +/- 0.15
```
Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.
From 1.96h to 7.43h, the decay slope is alpha = 1.1.
GCN Circular #12014
Andrea Tasselli (Lincoln, Lincolnshire, UK) reports to the AAVSO International High Energy Network the following optical observation of GRB 110503A (GCN Circ. #11991, Stamatikos et al.):
A. Tasselli (Lincoln, Lincolnshire, UK) reports a detection of GRB 110503A at an unfiltered, Sloan r-derived magnitude of cr = 19.1 +/- 0.1 on 2011 May 05.9167 (JD 2455685.4167; midpoint of exposures), approximately 4 hours after the Swift trigger (GCN Circ. #11991, Stamatikos et al.). Tasselli obtained 30 unfiltered images of 120 seconds exposure for a total of 3600 seconds. Tasselli used a 0.2-meter Maksutov-Cassegrain (f/6.8) with a Starlight SXV-H9 CCD camera. Photometry of the OT was done using the Iris photometry package with an ensemble of six SDSS stars:
```
SDSS J085118.11+521119.2, r=14.756;
SDSS J085118.96+521055.4, r=15.565;
SDSS J085110.02+521104.6, r=17.177;
SDSS J085119.59+521406.2, r=13.871;
SDSS J085131.83+521343.8, r=13.893; and
SDSS J085110.53+521301.8, r=17.749.
```
The position of the OT was measured using the Astrometrica package with 55 UCAC3 reference stars, and was found to be
```
 	RA(J2000)  =  08 51 06.2
 	Dec(J2000) = +52 12 30
```
in good agreement with other measurements.
The AAVSO International High Energy Network was made possible through grants from the Charles Curry Foundation and NASA.

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Jochen Greiner, last update: 16-May-2011 [Disclaimer]