Gamma-ray Burst 110915A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:21:00 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     503219,   Seg_Num: 0
GRB_RA:          310.851d {+20h 43m 24s} (J2000),
                 311.001d {+20h 44m 00s} (current),
                 310.207d {+20h 40m 50s} (1950)
GRB_DEC:          -0.709d {-00d 42' 33"} (J2000),
                  -0.667d {-00d 40' 00"} (current),
                  -0.890d {-00d 53' 24"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4647 [cnts]    Image_Peak=148 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   147     E_range: 25-100 keV
BKG_INTEN:       31296 [cnts]
BKG_TIME:        48032.63 SOD {13:20:32.63} UT
BKG_DUR:         8 [sec]
GRB_DATE:        15819 TJD;   258 DOY;   11/09/15
GRB_TIME:        48044.40 SOD {13:20:44.40} UT
GRB_PHI:          81.84 [deg]
GRB_THETA:        33.01 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.61 [sigma]
IMAGE_SIGNIF:    7.14 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -3  +0  +0 +74  +0 
SUN_POSTN:       172.98d {+11h 31m 56s}   +3.03d {+03d 01' 53"}
SUN_DIST:        137.98 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.71d {+01h 34m 51s}  +14.04d {+14d 02' 15"}
MOON_DIST:        73.41 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.88,-25.04 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      313.10, 16.83 [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 = 84.54,-14.37 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:22:34 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     503219,   Seg_Num: 0
GRB_RA:          310.8242d {+20h 43m 17.80s} (J2000),
                 310.9748d {+20h 43m 53.94s} (current),
                 310.1807d {+20h 40m 43.36s} (1950)
GRB_DEC:          -0.7231d {-00d 43' 23.1"} (J2000),
                  -0.6804d {-00d 40' 49.5"} (current),
                  -0.9039d {-00d 54' 14.1"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.02e-08 [erg/cm2/sec]
GRB_SIGNIF:      13.67 [sigma]
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48120.52 SOD {13:22:00.52} UT,   76.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.68 237.23 261.57 243.61
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       172.98d {+11h 31m 56s}   +3.03d {+03d 01' 52"}
SUN_DIST:        137.95 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.73d {+01h 34m 54s}  +14.04d {+14d 02' 29"}
MOON_DIST:        73.46 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.85,-25.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      313.07, 16.82 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.79 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:22:46 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     503219,   Seg_Num: 0
GRB_RA:          310.8242d {+20h 43m 17.8s} (J2000),
                 310.9748d {+20h 43m 53.9s} (current),
                 310.1807d {+20h 40m 43.3s} (1950)
GRB_DEC:          -0.7231d {-00d 43' 23.1"} (J2000),
                  -0.6804d {-00d 40' 49.5"} (current),
                  -0.9039d {-00d 54' 14.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       187 [cnts]
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48120.52 SOD {13:22:00.52} UT,   76.1 [sec] since BAT Trigger Time
CENTROID_X:      284.66,  raw= 285  [pixels]
CENTROID_Y:      304.01,  raw= 304  [pixels]
ROLL:            273.74 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   14.17
GRB_POS_XRT_Z:   -44.87
IMAGE_URL:       sw00503219000msxps_rw.img
SUN_POSTN:       172.98d {+11h 31m 56s}   +3.03d {+03d 01' 52"}
SUN_DIST:        137.95 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.73d {+01h 34m 55s}  +14.04d {+14d 02' 31"}
MOON_DIST:        73.46 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.85,-25.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      313.07, 16.82 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:22:55 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     503219,   Seg_Num: 0
GRB_RA:          310.8242d {+20h 43m 17.8s} (J2000),
                 310.9748d {+20h 43m 53.9s} (current),
                 310.1807d {+20h 40m 43.3s} (1950)
GRB_DEC:          -0.7231d {-00d 43' 23.1"} (J2000),
                  -0.6804d {-00d 40' 49.5"} (current),
                  -0.9039d {-00d 54' 14.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       187 [cnts]
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48120.52 SOD {13:22:00.52} UT,   76.1 [sec] since BAT Trigger Time
CENTROID_X:      284.66,  raw= 285  [pixels]
CENTROID_Y:      304.01,  raw= 304  [pixels]
ROLL:            273.74 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   14.17
GRB_POS_XRT_Z:   -44.87
IMAGE_URL:       sw00503219000msxps_rw.img
SUN_POSTN:       172.98d {+11h 31m 56s}   +3.03d {+03d 01' 51"}
SUN_DIST:        137.95 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.73d {+01h 34m 55s}  +14.04d {+14d 02' 32"}
MOON_DIST:        73.46 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.85,-25.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      313.07, 16.82 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:24:39 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     503219,   Seg_Num: 0
GRB_RA:          310.851d {+20h 43m 24s} (J2000),
                 311.001d {+20h 44m 00s} (current),
                 310.207d {+20h 40m 50s} (1950)
GRB_DEC:          -0.709d {-00d 42' 33"} (J2000),
                  -0.667d {-00d 40' 00"} (current),
                  -0.890d {-00d 53' 24"} (1950)
GRB_DATE:        15819 TJD;   258 DOY;   11/09/15
GRB_TIME:        48044.40 SOD {13:20:44.40} UT
TRIGGER_INDEX:   147
GRB_PHI:          81.84 [deg]
GRB_THETA:        33.01 [deg]
DELTA_TIME:      -56.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.61 [sigma]
IMAGE_SIGNIF:    7.14 [sigma]
LC_URL:          sw00503219000msb.lc
SUN_POSTN:       172.98d {+11h 31m 56s}   +3.03d {+03d 01' 50"}
SUN_DIST:        137.98 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.74d {+01h 34m 58s}  +14.05d {+14d 02' 49"}
MOON_DIST:        73.44 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.88,-25.04 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      313.10, 16.83 [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 = 84.54,-14.37 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:25:04 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.837d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 11"} (J2000)
POINT_ROLL:      273.737d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48129.23 SOD {13:22:09.23} UT,   84.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.333
N_STARS:         127
X_OFFSET:        424 [pixels]
Y_OFFSET:        680 [pixels]
X_MAX:           1383 [pixels]
Y_MAX:           1639 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00503219000msufc0084.fits
SUN_POSTN:       172.98d {+11h 31m 56s}   +3.03d {+03d 01' 49"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.75d {+01h 34m 59s}  +14.05d {+14d 02' 52"}
MOON_DIST:        73.46 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.09, 16.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:25:23 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.837d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 11"} (J2000)
POINT_ROLL:      273.737d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48129.23 SOD {13:22:09.23} UT,   84.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.333
N_STARS:         127
X_OFFSET:        424 [pixels]
Y_OFFSET:        680 [pixels]
X_MAX:           1383 [pixels]
Y_MAX:           1639 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00503219000msufc0084.fits
SUN_POSTN:       172.98d {+11h 31m 56s}   +3.03d {+03d 01' 49"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.75d {+01h 35m 00s}  +14.05d {+14d 02' 55"}
MOON_DIST:        73.47 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.09, 16.82 [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:     Thu 15 Sep 11 13:26:27 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.837d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 11"} (J2000)
ROLL:            273.737d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48129.23 SOD {13:22:09.23} UT,   84.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     337785736
X_OFFSET:        852 [pixels]
Y_OFFSET:        817 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1012
Y_GRB_POS:       977
BINNING_INDEX:   1
IM_URL:          sw00503219000msuni0092.fits
SUN_POSTN:       172.99d {+11h 31m 57s}   +3.03d {+03d 01' 48"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.76d {+01h 35m 02s}  +14.05d {+14d 03' 05"}
MOON_DIST:        73.47 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.09, 16.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:26:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.837d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 11"} (J2000)
ROLL:            273.737d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48129.23 SOD {13:22:09.23} UT,   84.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     337785736
X_OFFSET:        852 [pixels]
Y_OFFSET:        817 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1012
Y_GRB_POS:       977
BINNING_INDEX:   1
IM_URL:          sw00503219000msuni0092.fits
SUN_POSTN:       172.99d {+11h 31m 57s}   +3.03d {+03d 01' 48"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.76d {+01h 35m 03s}  +14.05d {+14d 03' 08"}
MOON_DIST:        73.48 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.09, 16.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #12335
S. T. Holland (CRESST/USRA/GSFC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), J. R. Cummings (NASA/UMBC), P. D'Avanzo (INAF-OAB), P. A. Evans (U Leicester), C. Gronwall (PSU), E. A. Hoversten (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), P. T. O'Brien (U Leicester), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU), C. A. Swenson (PSU) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift Team:
At 13:20:44 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110915A (trigger=503219). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 310.851, -0.709 which is
```
   RA(J2000)  =  20h 43m 24s
   Dec(J2000) = -00d 42' 33"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks with a total duration of about 95 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~68 sec after the trigger.
The XRT began observing the field at 13:22:00.5 UT, 76.1 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 310.8242, -0.7231 which is equivalent to:
```
    RA(J2000)  = 20h 43m 17.80s
    Dec(J2000) = -00d 43' 23.1"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 108 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 150 seconds with the White filter starting 84 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06.
Burst Advocate for this burst is S. T. Holland (Stephen.T.Holland 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:     Thu 15 Sep 11 13:31:33 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.835d {+20h 43m 20s} (J2000)
POINT_DEC:        -0.721d {-00d 43' 13"} (J2000)
POINT_ROLL:      273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48341.60 SOD {13:25:41.60} UT,   297.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.631
N_STARS:         107
X_OFFSET:        532 [pixels]
Y_OFFSET:        497 [pixels]
X_MAX:           1491 [pixels]
Y_MAX:           1456 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00503219000msufc0297.fits
SUN_POSTN:       172.99d {+11h 31m 57s}   +3.03d {+03d 01' 43"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.80d {+01h 35m 12s}  +14.06d {+14d 03' 53"}
MOON_DIST:        73.52 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:31:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.835d {+20h 43m 20s} (J2000)
POINT_DEC:        -0.721d {-00d 43' 13"} (J2000)
POINT_ROLL:      273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48341.60 SOD {13:25:41.60} UT,   297.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.631
N_STARS:         107
X_OFFSET:        532 [pixels]
Y_OFFSET:        497 [pixels]
X_MAX:           1491 [pixels]
Y_MAX:           1456 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00503219000msufc0297.fits
SUN_POSTN:       172.99d {+11h 31m 57s}   +3.03d {+03d 01' 43"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.80d {+01h 35m 12s}  +14.07d {+14d 03' 56"}
MOON_DIST:        73.52 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [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:     Thu 15 Sep 11 13:33:01 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.835d {+20h 43m 20s} (J2000)
POINT_DEC:        -0.721d {-00d 43' 13"} (J2000)
ROLL:            273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48341.60 SOD {13:25:41.60} UT,   297.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     337785948
X_OFFSET:        852 [pixels]
Y_OFFSET:        817 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1012
Y_GRB_POS:       977
BINNING_INDEX:   1
IM_URL:          sw00503219000msuni0305.fits
SUN_POSTN:       172.99d {+11h 31m 57s}   +3.03d {+03d 01' 42"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.81d {+01h 35m 15s}  +14.07d {+14d 04' 06"}
MOON_DIST:        73.53 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:33:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.835d {+20h 43m 20s} (J2000)
POINT_DEC:        -0.721d {-00d 43' 13"} (J2000)
ROLL:            273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48341.60 SOD {13:25:41.60} UT,   297.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     337785948
X_OFFSET:        852 [pixels]
Y_OFFSET:        817 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1012
Y_GRB_POS:       977
BINNING_INDEX:   1
IM_URL:          sw00503219000msuni0305.fits
SUN_POSTN:       172.99d {+11h 31m 58s}   +3.03d {+03d 01' 41"}
SUN_DIST:        137.96 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.81d {+01h 35m 16s}  +14.07d {+14d 04' 10"}
MOON_DIST:        73.53 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:38:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.836d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 12"} (J2000)
POINT_ROLL:      273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48921.31 SOD {13:35:21.31} UT,   876.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.194
N_STARS:         190
X_OFFSET:        292 [pixels]
Y_OFFSET:        257 [pixels]
X_MAX:           1731 [pixels]
Y_MAX:           1696 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00503219000msufc0876.fits
SUN_POSTN:       172.99d {+11h 31m 58s}   +3.03d {+03d 01' 37"}
SUN_DIST:        137.95 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.85d {+01h 35m 25s}  +14.08d {+14d 04' 56"}
MOON_DIST:        73.57 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:38:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.836d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 12"} (J2000)
POINT_ROLL:      273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48921.31 SOD {13:35:21.31} UT,   876.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.194
N_STARS:         190
X_OFFSET:        292 [pixels]
Y_OFFSET:        257 [pixels]
X_MAX:           1731 [pixels]
Y_MAX:           1696 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00503219000msufc0876.fits
SUN_POSTN:       172.99d {+11h 31m 58s}   +3.03d {+03d 01' 36"}
SUN_DIST:        137.95 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.86d {+01h 35m 26s}  +14.08d {+14d 04' 60"}
MOON_DIST:        73.57 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [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:     Thu 15 Sep 11 13:39:05 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     503219,   Seg_Num: 0
GRB_RA:          310.8258d {+20h 43m 18.19s} (J2000),
                 310.9764d {+20h 43m 54.32s} (current),
                 310.1823d {+20h 40m 43.74s} (1950)
GRB_DEC:          -0.7245d {-00d 43' 28.2"} (J2000),
                  -0.6818d {-00d 40' 54.6"} (current),
                  -0.9053d {-00d 54' 19.1"} (1950)
GRB_ERROR:       5.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48620.00 SOD {13:30:20.00} UT,   575.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       172.99d {+11h 31m 58s}   +3.03d {+03d 01' 36"}
SUN_DIST:        137.94 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.86d {+01h 35m 26s}  +14.08d {+14d 05' 02"}
MOON_DIST:        73.59 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.85,-25.03 [deg] galactic lon,lat of the burst
ECL_COORDS:      313.07, 16.82 [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 1.1% < P(seren) < 2.8%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 15 Sep 11 13:39:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.836d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 12"} (J2000)
ROLL:            273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48921.31 SOD {13:35:21.31} UT,   876.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     337786528
X_OFFSET:        851 [pixels]
Y_OFFSET:        816 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       976
BINNING_INDEX:   1
IM_URL:          sw00503219000msuni0884.fits
SUN_POSTN:       172.99d {+11h 31m 59s}   +3.03d {+03d 01' 35"}
SUN_DIST:        137.95 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.87d {+01h 35m 28s}  +14.09d {+14d 05' 09"}
MOON_DIST:        73.58 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [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:     Thu 15 Sep 11 13:40:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     503219,   Seg_Num: 0
POINT_RA:        310.836d {+20h 43m 21s} (J2000)
POINT_DEC:        -0.720d {-00d 43' 12"} (J2000)
ROLL:            273.736d
IMG_START_DATE:  15819 TJD;   258 DOY;   11/09/15
IMG_START_TIME:  48921.31 SOD {13:35:21.31} UT,   876.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     337786528
X_OFFSET:        851 [pixels]
Y_OFFSET:        816 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       976
BINNING_INDEX:   1
IM_URL:          sw00503219000msuni0884.fits
SUN_POSTN:       172.99d {+11h 31m 59s}   +3.03d {+03d 01' 35"}
SUN_DIST:        137.95 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:       23.87d {+01h 35m 28s}  +14.09d {+14d 05' 12"}
MOON_DIST:        73.58 [deg]
MOON_ILLUM:      91 [%]
GAL_COORDS:       45.86,-25.04 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      313.08, 16.82 [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 #12336
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 110915A, we find an enhanced XRT position of the afterglow: RA, Dec: 310.8242, -0.7241 which is equivalent to:
```
   RA (J2000)  = 20 43 17.81
   Dec (J2000) = -00 43 26.7
```
with an uncertainty of 3.4 arc sec (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/503219.
Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #12337
V.Yurkov, Yu.Sergienko, E.Sinyakov, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk
K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev,E.Konstantinov, Irkutsk State University
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.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Sankovich Sternberg Astronomical Institute, Moscow State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka
MASTER robotic telescope (MASTER-Net: http://observ.pereplet.ru) located at Blagoveschensk (Amur-site) was pointed to the GRB110915A 15 sec after notice time and 31 sec after GRB time at 2011-09-15 13:21:15 UT. On our first (10s exposure) MASTER II telescope set we haven`t found optical transient within SWIFT error-box (Holland et al., GCN Circ 12335). Unfortunatelly the main telescopes was not in focus.
On our first (5s exposure) MASTER VWF (Very Wide Field Camera - FOV=420 square degrees) set we haven`t found optical transient within SWIFT error-box (Holland et al., GCN Circ 12335).
```
       Date           T_start-T_trig     ExpTime   Limit  Coadd  Instrum
       (UT)                  (s)            (s)   (unfilt)
      13:21:15               31             10      12      No  MASTER II
      13:21:17               33              5      12      No  MASTER VWF
      13:21:17               33             60      14      12  MASTER VWF
```
The message may be cited.
GCN Circular #12338
K. Kawakami, K. Tokoyoda, Y. Yatsu, Y. Aoki, M. Hayashi, S. Song, R. Usui, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed GRB 110915A (S. T. Holland et al, GCN12335) with the optical three color (g, Rc, and Ic) CCD camera attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The follow-up observation was started at 14:29:30, ~69 min after the BAT trigger.
We did not find any new point source within the enhanced XRT error circle (P.A. Evans et al., GCNC 12336) in two bands.
Photometric results and are listed below. We used GSC2.3 catalog for flux calibration.
```
T0+[s]      MID-UT     T-EXP[sec]      g'             Rc           Ic
-------------------------------------------------------------------------------
 +4126   14:34:59          1440           ---          >17.6     >17.6
-------------------------------------------------------------------------------
T0+ : Elapsed time after the burst [sec]
T-EXP: Total Exposure time [sec]
```
GCN Circular #12339
X.-H. Zhao (YNAO), D. Xu (WIS), J.-R. Mao & J.-M. Bai (YNAO) report on a larger collaboration:
We observed the XRT field (Evans, GCN 12336) of GRB 110915A (Holland et al., GCN 12335) with the 2.4m GMG telescope in Yunnan, China equipped with YFOSC. Observations started at 13:58:09 UT, 15th Sep. 2011 (i.e., 0.6236 hr after the burst), and 1x20 min R-band and 1x20 min V-band images were obtained under the cloudy weather.
No optical source was present within the XRT error circle in GCN #12336, which sets a 3\sigma upper limit of R~21.6 mag, calibrated with the USNO B1 catalog.
GCN Circular #12340
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 2062 s of XRT Photon Counting mode data and 4 UVOT images for GRB 110915A, 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 = 310.82447, -0.72312 which is equivalent to:
```
RA (J2000): 20h 43m 17.87s
Dec (J2000): -00d 43' 23.2"
```
with an uncertainty of 1.6 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 #12342
R. Sanchez-Ramirez (IAA-CSIC), N. Morales (IAA-CSIC), J. Gorosabel (IAA-CSIC), J.L. Ortiz (IAA-CSIC), P. Kubanek (U. Valencia & IAA-CSIC), A. de Ugarte Postigo (DARK/NBI), A.J. Castro-Tirado (IAA-CSIC), report on behalf of a larger collaboration:
"We imaged the field of the Swift GRB 110915A (Holland et al., GCN Circ 12335) with the 1.23m Calar Alto telescope. The observations were carried out in the I-band on Sep 15.7984-15.8500 UT (starting 5.81 hours after the GRB) with a total exposure time of 25 X 180 = 4500s. No object brighter than I=21.5 is detected in the XRT error circle (Evans et al., GCN Circ 12340)."
GCN Circular #12343
D. Malesani (DARK, NBI), P. Jakobsson (U. Iceland), A. de Ugarte Postigo (DARK, NBI), J. Lykke (NOT), D. Xu (WIS), and N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration:
Using ALFOSC on the Nordic Optical Telescope (NOT) we have obtained R-band (3 x 600 s) and z-band (18 x 300 s) imaging of the GRB 110915A field (Holland et al., GCN 12335) starting on 2011 September 15.87 UT (around 7.5 hr after the burst).
We do not detect any object within the refined XRT error circle (Evans et al., GCN 12340). The limiting magnitudes are R(Vega) = 24.3 and z(AB) = 23.5, calibrated against the USNO-B1 and SDSS catalogs, respectively.
Using our R-band limit and preliminary X-ray fluxes, we obtain a corresponding upper limit on beta_OX of around 0.1, rendering the burst dark according to the definition proposed by Jakobsson et al. (2004, ApJ, 617, L21). This burst may therefore be at high redshift, or suffer from significant dust extinction. The presence of significant excess absorption in the X-ray afterglow spectrum (http://www.swift.ac.uk/xrt_spectra/00503219/) makes the second option more likely.
GCN Circular #12344
D. Kuroda, (OAO, NAOJ), H. Hanayama (IAO, NAOJ), K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), T. Miyaji J. Watanabe, (IAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 110915A (Holland et al., GCNC 12335) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory and the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
We did not find any new point source within the enhanced XRT error circle (Evans, GCNC 12336) in all the three bands.
Three sigma upper limits of the OT are listed below. We used SDSS catalog for flux calibration.
Ishigakijima Astronomical Observatory: The observation started on 2011-09-15 13:28:55 UT (~8.2 min after the burst).
```
T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.07421    15:07:35    9360.0    >22.0  >21.8  >20.7
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
Okayama Astrophysical Observatory: The observation started on 2011-09-15 14:58:17 UT (~1.6 h after the burst).
```
T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.08645    15:25:12    3060.0    >19.8 >20.2  >19.34
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #12345
Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Kiichi Okita (OAO/NAOJ), Michitoshi Yoshida (Hiroshima-U), Kouji Ohta(Kyoto-U) and Nobuyuki Kawai(Tokyo Tech.) report on behalf of the MITSuME collaboration.
We observed the field of GRB110915A (Holland et al, GCN12355) in J-band with a wide-field near infrared imager at Okayama Astrophysical Observatory (Japan). The imager has effective aperture of 0.91 m.
Observations started from 15:19 UT on 15th September, just 2 hours after the BAT trigger, to 16:02 UT. The total exposure of 35 min was successfully obtained.
In our co-add image, we did not find any new point source within the enhanced XRT error circle (P.A. Evans et al., GCNC 12340) down to limiting magnitude of J=17.3 (Vega, S/N=3) . The photometric calibration was made against 2MASS field stars.
```
T0+[s]      MID-UT     T-EXP[sec]      J
---------------------------------------------------
 +8130      15:35          2110       >17.3
---------------------------------------------------
T0+ : Elapsed time after the burt [sec]
T-EXP: Total Exposure time [sec]
```
GCN Circular #12346
D. A. Perley (Caltech), A. Cucchiara (UC Santa Cruz), and N. R. Tanvir (Leicester) report on behalf of a larger collaboration:
We imaged the field of GRB 110915A (Holland et al., GCN 12335) with GMOS-S on Gemini-South starting at 00:36 UT on 2011-09-16. We acquired 6x240 seconds in i-band, and 7x240 seconds in z-band. Conditions were clear with generally good seeing (0.7").
We find no significant sources within the XRT error circle in either filter. We calculate the following 3-sigma limits:
```
   i > 26.0 mag  (t_mid = 11.49 hr)
   z > 24.9 mag  (t_mid = 12.03 hr)
```
Given the bright X-ray afterglow and and other optical limits reported to date, these results indicate that GRB 110915A is a very dark burst, as also noted by Malesani et al (GCN 12343). Infrared and radio follow-up is encouraged.
GCN Circular #12349
E. Berger, R. Chornock, J. Strader (Harvard) and L. Spitler (Swinburne) report:
"We imaged the field of GRB 110915A (GCN 12335) with the FourStar near-IR imager mounted on the Magellan/Baade 6.5-m telescope starting on 2011 Sep 16.155 UT (14.4 hr after the burst). Observations were obtained in the J and Ks filters in good seeing (0.6"). We do not detect any sources in coincidence with the enhanced XRT position (GCN 12340) to a 3-sigma limit of J>23.5 mag and Ks>23.0 mag (AB). The X-ray flux on the same timescale (extrapolated from the existing XRT light curve) is F_X ~ 4e-12 cgs, indicating an expected near-IR brightness of J~19 mag and K~18.5 mag. If due to extinction, the required ~4.5 mag in J and Ks are suggestive of an unusually large A_V."
GCN Circular #12351
B. Sbarufatti (INAF-OAB/IASFPA) and S. T. Holland (CRESST/USRA/GSFC) report on behalf of the Swift-XRT team:
We have analysed 3.3 ks of XRT data for GRB 110915A (Holland et al. GCN Circ. 12335), from 82 s to 7.7 ks after the BAT trigger. The data comprise 1.6 ks in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN. Circ 12336).
The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=5.6 (+0.6, -0.4). At T+120 s the decay flattens to an alpha of 0.49 (+0.15, -1.09) before breaking again at T+309 s to a final decay with index alpha=0.84 (+0.04, -0.03).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.98 (+/-0.05). The best-fitting absorption column is 2.69 (+0.18, -0.17) x 10^21 cm^-2, in excess of the Galactic value of 5.3 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.04 (+0.21, -0.20) and a best-fitting absorption column of 2.6 (+/-0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 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 (+/-0.7) x 10^21 cm^-2
Galactic foreground: 5.3 x 10^20 cm^-2
Excess significance: 6.5 sigma
Photon index:	     2.04 (+0.21, -0.20)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00503219.
This circular is an official product of the Swift-XRT team.
GCN Circular #12352
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), S. T. Holland (CRESST/USRA/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-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 110915A (trigger #503219) (Holland, et al., GCN Circ. 12335). The BAT ground-calculated position is RA, Dec = 310.830, -0.713 deg which is
```
     RA(J2000)  =  20h 43m 19.2s
     Dec(J2000) = -00d 42' 45.8"
```
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 25%.
The light curve consists first of a group of multiple overlapping peaks lasting from T0-5 sec to T0+45 sec. This is followed by a second cluster from T0+55 sec to T0+85 sec, containing the brightest peak at ~T0+70 sec. T90 (15-350 keV) is 78.76 +- 1.25 sec (estimated error including systematics).
The time-averaged spectrum from -2.74 to 92.1 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.94 +- 0.23, and Epeak of 124.8 +- 41.4 keV (chi squared 58.07 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.7 +- 0.2 x 1006 erg/cm2 and the 1-sec peak flux measured from T+68.04 sec in the 15-150 keV band is 3.3 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.41 +- 0.05 (chi squared 72.11 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/503219/BA/
GCN Circular #12353
J. Elliott (MPE Garching), D. A. Kann (Tautenburg Obs.), and J. Greiner (also MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 110915A (Swift trigger 503219; Holland et al., GCN 12335) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile).
Observations started at 23:26 UT on 15 September, 10.1 hours after the GRB trigger. They were performed at an average seeing of 1.1 and at an average airmass of 1.2.
We do not detect a source within the enhanced UVOT/Swift-XRT error circle reported by Evans et al. (GCN 12340). For a total exposure time of 6003 s in g'r'i'z' and 4800 s in JHK, we do not detect a source down to:
```
g' > 25.5,
r' > 25.4,
i' > 24.3,
z' > 23.8,
J > 21.2,
H > 20.0, and
K > 18.6
```
The given limits are derived based on calibrating the images against GROND zeropoints (g'r'i'z' are AB mags) and 2MASS field stars (JHK are Vega mags) and are not corrected for the Galactic foreground extinction corresponding to a reddening of E(B-V) = 0.058 in the direction of the burst (Schlegel et al. 1998).
These upper limits are in agreement with the i/z upper limits from Perley et al. (GCN 12345) and the J/Ks upper limits from Berger et al. (GCN 12349).
GCN Circular #12355
E. A. Hoversten (PSU) and S. T. Holland (CRESST/USRA/GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 110915A 84 ks after the BAT trigger (Holland et al., GCN Circ. 12335). No optical afterglow consistent with the enhanced XRT position (Evans et al., GCN Circ. 12340) is detected in the initial UVOT exposures. UVOT magnitude 3-sigma upper limits are reported in the following table:
```
Filter  T_start  T_stop  Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white      84     1884    429       > 21.46
v         616     5316    203       > 19.35
b         540     1858    136       > 20.10
u         284     1834    362       > 20.36
uvw1      665     1809    136       > 19.59
uvm2      641     1784    136       > 19.46
uvw2      592     1897    144       > 19.82
```
The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.06 (Schlegel et al. 1998). All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular #12358
V. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, and T. Cline on behalf of the Konus-Wind team,
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), and T. Ukwatta (GWU)
report:
We performed the Konus-Wind and the Swift/BAT joint spectral analysis of GRB 110915A (Swift/BAT trigger #503219: Holland et al., GCN Circ. 12335, Ukwatta et al. GCN Circ. 12352). Since the Konus-Wind observed this GRB in the waiting mode, we only have 3 channel spectral data for the Konus-Wind which cover the energy range from 20 keV to 1.2 MeV. The joint spectral analysis of the Konus-Wind and the Swift/BAT data allows us to derive the broad-band spectral parameters of this burst.
The time interval of the spectral data for each instrument is chosen from T0(BAT)-3.3 to T0(BAT)+82.1 s where T0(BAT) is the trigger time of BAT at 13:20:44.40 UTC. The energy ranges which we used in the joint spectral analysis are 20-1200 keV and 14-150 keV for the Konus-Wind and the Swift/BAT respectively. The spectral data of two instruments are fitted with the spectral model multiplied by the constant factor to take into account the systematic effective area uncertainties in the response matrices of each instrument.
The spectrum is well fitted with a power-law with exponential cutoff model: dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak). No systematic residual from the best fit model is seen in the spectral data of each instrument. The BAT constant factor is 0.76(-0.08,+0.09) (the KW constant factor is fixed to 1). The best fit spectral parameters are: alpha = -1.08 (-0.14/+0.19) and Epeak = 183 (-48/+80) keV (chi2/dof = 62/58). The best fit spectral parameters for the GRB (Band) model are: alpha = -0.90(-0.21,+0.24), beta = -2.2(-0.8,+0.3), and Epeak = 132(-28,+57) keV (chi2/dof = 58/57). The derived alpha and Epeak are in agreement with those derived from analysis of the BAT data alone (Ukwatta et al. GCN Circ. 12352). The energy fluence in the 15-1200 keV band calculated by a power-law with exponential cutoff model for this 85.4 s interval is 1.35(-0.20,+0.25)x10^-5 erg/cm2.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110915A/
All the quoted errors are at the 90% confidence level.
GCN Report 344.1
GCN_Report 344.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_344_1.pdf by S.T. Holland at CRESST/USRA/GSFC titled: "Final Swift Observations of GRB 110915A"

GCN Circular #12786
V.V. Golovnya (Main Astro Obs, Kyiv) report:
We have undertaken the review of the sky area in vicinity of=20 GRB 110915A (Evans et al., GCN Circ.12340) on astronegatives, collected in Ukrainian NAS Main astronomical observatory plate=20 archive (1976-1996). All the plates with the possible object=20 appearance are digitized using Microtek ScanMaker 9800XL TMA=20 and Epson Expression 10000XL flatbed scanners and have been=20 placed into Golosiiv Plate Archive database DBGPA with open=20 access to them.

 	The list of plates is given in the table:
YYYYMMDD/TimeUT	--Plates--	Exp.	LimMag	Star USNOA2=20
19810930/180433	GUA040C000001A	27.0	16.50	0825-18636133
19820827/205711	GUA040C002422	60.3	14.40	0825-18638528
19820827/205711	GUA040D002423	60.3	14.40	0825-18638528
19820827/223853	GUA040C002424	15.0	13.75	0825-18638504
19820909/165505	TAS040A000325	23.0	17.10	0825-18635715
19820918/160521	TAS040A000331	23.0	16.50	0825-18636133
19910709/231157	GUA040C001830A	22.5	15.50	0825-18638699
Plates: =20
GUA040C,=96the plates archive identifier of DWA (D/F=3D400/2000,=20
GUA040D  M=3D103"/mm) of the Ukrainian NAS Main Astro obs.
         (Marsden's number - 83) the plate number [1].
TAS040A -the plates archive identifier of DAZ (D/F=3D400/3000,
         M=3D68.8"/mm) of the Tashkent Astro obs.
         (Marsden's number - 186) the plate number [1].
Exp.   - Duration of the maximum exposure (minutes).=20
LimMag - Limited V mag, derived in the 15 minutes area around=20
       the location given in GCN Circ.12340:=20
       RA(J2000): 20h 43m 17.87s, Dec(J2000): -00d 43' 23.2"
Star USNOA2 - Comparison star.
  The preview images of 7 areas together with =20
the 15x15 min.of arc area from SkyMap can be found in =20
http://gua.db.ukr-vo.org/img/grb/110915A/index.html
The images with full resolution are available via e-mail on demand.
References:
1. L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0),
http://gua.db.ukr-vo.org

Back to JG's homepage

Jochen Greiner, last update: 30-Dec-2011 [Disclaimer]