Gamma-ray Burst 060923

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:12:28 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     230662,   Seg_Num: 0
GRB_RA:          254.623d {+16h 58m 30s} (J2000),
                 254.701d {+16h 58m 48s} (current),
                 254.041d {+16h 56m 10s} (1950)
GRB_DEC:         +12.379d {+12d 22' 45"} (J2000),
                 +12.369d {+12d 22' 09"} (current),
                 +12.454d {+12d 27' 15"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4846 [cnts]    Image_Peak=162 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       32994 [cnts]
BKG_TIME:        18718.53 SOD {05:11:58.53} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14001 TJD;   266 DOY;   06/09/23
GRB_TIME:        18735.37 SOD {05:12:15.37} UT
GRB_PHI:         -78.72 [deg]
GRB_THETA:        33.49 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.87 [sigma]
IMAGE_SIGNIF:    7.22 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +1  +0  +0 -25  +1 
SUN_POSTN:       180.04d {+12h 00m 10s}   -0.02d {-00d 01' 04"}
SUN_DIST:         75.03 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      186.93d {+12h 27m 43s}   -4.23d {-04d 13' 44"}
MOON_DIST:        69.35 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:       31.61, 30.60 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      251.60, 34.84 [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 = 201.92,19.12 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:13:42 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.649d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18816.45 SOD {05:13:36.45} UT,   81.1 [sec] since BAT Trigger Time
COUNTS:          7    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        2    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:15:40 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.649d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
POINT_ROLL:      266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18820.26 SOD {05:13:40.26} UT,   84.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.537
N_STARS:         87
X_OFFSET:        642 [pixels]
Y_OFFSET:        447 [pixels]
X_MAX:           1601 [pixels]
Y_MAX:           1406 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00230662000msufc0084.fits
SUN_POSTN:       180.04d {+12h 00m 10s}   -0.02d {-00d 01' 07"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      186.95d {+12h 27m 48s}   -4.24d {-04d 14' 30"}
MOON_DIST:        69.35 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.63, 34.85 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:16:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.649d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
POINT_ROLL:      266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18820.26 SOD {05:13:40.26} UT,   84.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.537
N_STARS:         87
X_OFFSET:        642 [pixels]
Y_OFFSET:        447 [pixels]
X_MAX:           1601 [pixels]
Y_MAX:           1406 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00230662000msufc0084.fits
SUN_POSTN:       180.04d {+12h 00m 11s}   -0.02d {-00d 01' 07"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      186.95d {+12h 27m 49s}   -4.24d {-04d 14' 35"}
MOON_DIST:        69.35 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.63, 34.85 [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:     Sat 23 Sep 06 05:17:00 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.649d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
ROLL:            266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18820.26 SOD {05:13:40.26} UT,   84.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     180681221
X_OFFSET:        961 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00230662000msuni0084.fits
SUN_POSTN:       180.04d {+12h 00m 11s}   -0.02d {-00d 01' 08"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      186.96d {+12h 27m 51s}   -4.25d {-04d 14' 48"}
MOON_DIST:        69.35 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.63, 34.85 [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:     Sat 23 Sep 06 05:17:14 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     230662,   Seg_Num: 0
GRB_RA:          254.623d {+16h 58m 30s} (J2000),
                 254.701d {+16h 58m 48s} (current),
                 254.041d {+16h 56m 10s} (1950)
GRB_DEC:         +12.379d {+12d 22' 45"} (J2000),
                 +12.369d {+12d 22' 09"} (current),
                 +12.454d {+12d 27' 15"} (1950)
GRB_DATE:        14001 TJD;   266 DOY;   06/09/23
GRB_TIME:        18735.37 SOD {05:12:15.37} UT
TRIGGER_INDEX:   148
GRB_PHI:         -78.72 [deg]
GRB_THETA:        33.49 [deg]
DELTA_TIME:      77.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.87 [sigma]
IMAGE_SIGNIF:    7.22 [sigma]
LC_URL:          sw00230662000msb.lc
SUN_POSTN:       180.04d {+12h 00m 11s}   -0.02d {-00d 01' 08"}
SUN_DIST:         75.03 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      186.96d {+12h 27m 51s}   -4.25d {-04d 14' 52"}
MOON_DIST:        69.32 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:       31.61, 30.60 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      251.60, 34.84 [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 = 201.92,19.12 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:17:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.649d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
ROLL:            266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18820.26 SOD {05:13:40.26} UT,   84.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     180681221
X_OFFSET:        961 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00230662000msuni0084.fits
SUN_POSTN:       180.04d {+12h 00m 11s}   -0.02d {-00d 01' 08"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      186.96d {+12h 27m 51s}   -4.25d {-04d 14' 51"}
MOON_DIST:        69.35 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.63, 34.85 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:23:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.651d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
POINT_ROLL:      266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18926.01 SOD {05:15:26.01} UT,   190.6 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.487
N_STARS:         109
X_OFFSET:        642 [pixels]
Y_OFFSET:        447 [pixels]
X_MAX:           1601 [pixels]
Y_MAX:           1406 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00230662000msufc0190.fits
SUN_POSTN:       180.05d {+12h 00m 12s}   -0.02d {-00d 01' 14"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.01d {+12h 28m 02s}   -4.27d {-04d 16' 17"}
MOON_DIST:        69.31 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.64, 34.85 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:23:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.651d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
POINT_ROLL:      266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18926.01 SOD {05:15:26.01} UT,   190.6 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.487
N_STARS:         109
X_OFFSET:        642 [pixels]
Y_OFFSET:        447 [pixels]
X_MAX:           1601 [pixels]
Y_MAX:           1406 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00230662000msufc0190.fits
SUN_POSTN:       180.05d {+12h 00m 12s}   -0.02d {-00d 01' 15"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.01d {+12h 28m 02s}   -4.27d {-04d 16' 22"}
MOON_DIST:        69.31 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.64, 34.85 [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:     Sat 23 Sep 06 05:24:26 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.651d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
ROLL:            266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18926.01 SOD {05:15:26.01} UT,   190.6 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     180681327
X_OFFSET:        961 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00230662000msuni0190.fits
SUN_POSTN:       180.05d {+12h 00m 12s}   -0.02d {-00d 01' 15"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.02d {+12h 28m 04s}   -4.28d {-04d 16' 34"}
MOON_DIST:        69.30 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.64, 34.85 [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:     Sat 23 Sep 06 05:24:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.651d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
ROLL:            266.609d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18926.01 SOD {05:15:26.01} UT,   190.6 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     180681327
X_OFFSET:        961 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00230662000msuni0190.fits
SUN_POSTN:       180.05d {+12h 00m 12s}   -0.02d {-00d 01' 16"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.02d {+12h 28m 04s}   -4.28d {-04d 16' 38"}
MOON_DIST:        69.30 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.64, 34.85 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:28:00 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.651d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
POINT_ROLL:      266.608d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  19603.83 SOD {05:26:43.83} UT,   868.5 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        0.220
N_STARS:         46
X_OFFSET:        642 [pixels]
Y_OFFSET:        447 [pixels]
X_MAX:           1601 [pixels]
Y_MAX:           1406 [pixels]
DET_THRESH:      5
PHOTO_THRESH:    2
SL_URL:          sw00230662000msufc0868.fits
SUN_POSTN:       180.05d {+12h 00m 12s}   -0.02d {-00d 01' 19"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.04d {+12h 28m 10s}   -4.29d {-04d 17' 24"}
MOON_DIST:        69.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.64, 34.85 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:29:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.651d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
ROLL:            266.608d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  19603.83 SOD {05:26:43.83} UT,   868.5 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     180682005
X_OFFSET:        961 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00230662000msuni0868.fits
SUN_POSTN:       180.05d {+12h 00m 12s}   -0.02d {-00d 01' 20"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.05d {+12h 28m 12s}   -4.29d {-04d 17' 39"}
MOON_DIST:        69.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.64, 34.85 [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:     Sat 23 Sep 06 05:29:19 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     230662,   Seg_Num: 0
POINT_RA:        254.651d {+16h 58m 36s} (J2000)
POINT_DEC:       +12.383d {+12d 22' 58"} (J2000)
ROLL:            266.608d
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  19603.83 SOD {05:26:43.83} UT,   868.5 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     180682005
X_OFFSET:        961 [pixels]
Y_OFFSET:        766 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1121
Y_GRB_POS:       926
BINNING_INDEX:   1
IM_URL:          sw00230662000msuni0868.fits
SUN_POSTN:       180.05d {+12h 00m 12s}   -0.02d {-00d 01' 20"}
SUN_DIST:         75.05 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.05d {+12h 28m 12s}   -4.30d {-04d 17' 43"}
MOON_DIST:        69.27 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.62, 30.58 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      251.64, 34.85 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 23 Sep 06 05:38:26 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     230662,   Seg_Num: 0
GRB_RA:          254.6177d {+16h 58m 28.2s} (J2000),
                 254.6960d {+16h 58m 47.0s} (current),
                 254.0361d {+16h 56m 08.6s} (1950)
GRB_DEC:         +12.3620d {+12d 21' 43.2"} (J2000),
                 +12.3521d {+12d 21' 07.5"} (current),
                 +12.4372d {+12d 26' 13.9"} (1950)
GRB_ERROR:       9.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.70e-11 [erg/cm2/sec]
GRB_SIGNIF:      5.00 [sigma]
IMG_START_DATE:  14001 TJD;   266 DOY;   06/09/23
IMG_START_TIME:  18816.45 SOD {05:13:36.45} UT,   81.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.61 237.19 261.35 242.66
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       180.06d {+12h 00m 14s}   -0.03d {-00d 01' 29"}
SUN_DIST:         75.01 [deg]   Sun_angle= -5.0 [hr] (East of Sun)
MOON_POSTN:      187.12d {+12h 28m 28s}   -4.33d {-04d 19' 51"}
MOON_DIST:        69.18 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       31.59, 30.60 [deg] galactic lon,lat of the burst
ECL_COORDS:      251.60, 34.82 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values are not valid.

GCN Circular #5583
M. Stamatikos (NASA/ORAU), D. N. Burrows (PSU), M. Capalbi (ASDC), M.L. Conciatore (ASDC), N. Gehrels (NASA/GSFC), C. Guidorzi (Univ Bicocca&INAF-OAB), S. T. Holland (GSFC/USRA), D. M. Palmer (LANL), M. Perri (ASDC), T. Sakamoto (NASA/ORAU) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 05:12:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060923 (trigger=230662). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 254.623, +12.379 {16h 58m 30s, +12d 22' 45"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed at least two peaks, lasting 12 seconds. The peak count rate was ~1200 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began taking data at 05:13:36 UT, 81 seconds after the BAT trigger. The XRT found a previously uncatalogued X-ray source in the field of view at the following coordinates:
```
   RA(J2000) =  16 58 28.27
   Dec(J2000)=  +12 21 43.3
```
with an uncertainty of 6.9 arcseconds radius (90% containment). This position lies 67 arcseconds from the center of the BAT error circle. The approximate initial flux is 1.7e-11 erg/cm2/sec (0.2-10 keV).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 85 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The overlap of the sub-image and the XRT error circle is 100%. The overlap of the 8'x8' region for the list of sources generated on-board and the XRT error circle is 100%. The limiting magnitude of the finding chart image is approximately 18.5. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06.
GCN Circular #5584
W. Li, N. Butler, J. S. Bloom, and A. V. Filippenko, University of California, Berkeley, on behalf of the KAIT GRB team, report:
The robotic 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory observed GRB 060923, detected with Swift (Trigger 230662; Stamatikos et al. GCN 5583). The automatic sequence started at 05:12:33, 18 s after the burst. The first two images, however, failed due to some technical issues. In subsequent images, Our image processing pipeline did not find any new objects, and reported the following photometry limits (calibrated with USNO B1.0):
======================================================================
```
Start UT   t(GRB)   Filter    Exp(s)  3sigma-limit      

05:13:57    102s    I         15.0     <16.9
05:14:21    126s    clear     20.0     <17.9
05:14:52    157s    V         45.0     <16.9
05:15:48    213s    I         45.0     <17.5
05:16:43    268s    clear     45.0     <18.5
05:17:39    324s    V         60.0     <17.2
```
========================================================================
More analyses are in progress.
GCN Circular #5585
Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg (NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J. Brinkmann (APO), Donald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel E. Vanden Berk (PSU) report:
The Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB060923 prior to the burst. As these data should be useful as a pre-burst comparison and for calibrating photometry, we are supplying the images and photometry measurements for this GRB field to the community.
Data from the SDSS, including 5 FITS images, 3 JPGS, and 3 files of photometry and astrometry, are being placed at http://mizar.as.arizona.edu/~grb/public/GRB060923
We supply FITS images in each of the 5 SDSS bands of a 8'x8' region centered on the GRB position (ra=254.618 (16:58:28.3), dec=12.3620 (12:21:43.2); GCN 5583), as well as 3 gri color-composite JPGs (with different stretches). The units in the FITS images are nanomaggies per pixel. A pixel is 0.396 arcsec on a side. A nanomaggie is a flux-density unit equal to 10^-9 of a magnitude 0 source or, to the extent that SDSS is an AB system, 3.631e-6 Jy. The FITS images have WCS astrometric information.
In the file GRB060923_sdss.calstar.dat, we report photometry and astrometry of 1668 bright stars (r<20.5) within 15' of the burst location. The magnitudes presented in this file are asinh magnitudes as are standard in the SDSS (Lupton 1999, AJ, 118, 1406). Beware that some of these stars are not well-detected in the u-band; use the errors and object flags to monitor data quality.
In the files GRB060923_sdss.objects_flux.dat and GRB060923_sdss.objects_magnitudes.dat, we report photometry of 2573 objects detected within 6' of the GRB position. We have removed saturated objects and objects with model magnitudes fainter than 23.0 in the r-band. The fluxes listed in GRB060923_sdss.objects_flux.dat are in nanomaggies while the magnitudes listed in GRB060923_sdss.objects_magnitudes.dat are asinh magnitudes.
All quantities reported are standard SDSS photometry, meaning that they are very close to AB zeropoints and magnitudes are quoted in asinh magnitudes. Photometric zeropoints are known to about 2% rms. None of the photometry is corrected for dust extinction. The Schlegel, Finkbeiner, and Davis (1998) predictions for this region are A_U=0.287 mag, A_g=0.211 mag, A_r = 0.153 mag, A_i=0.116 mag, and A_z=0.082 mag.
There are currently no objects within 6 arcminutes of the GRB position in the SDSS spectroscopic database.
SDSS astrometry is generally better than 0.1 arcsecond per coordinate. Users requiring high precision astrometry should take note that the SDSS astrometric system can differ from other systems such as those used in other notices; we have not checked the offsets in this region.
More detailed information pertaining to our SDSS GRB releases can be found in our initial data release paper (Cool et al. 2006, astro-ph/0601218). See the SDSS DR4 documentation for more details: http://www.sdss.org/dr5.
These data have been reduced using a slightly different pipeline than that used for SDSS public data releases. We cannot guarantee that the values here will exactly match those in the data release in which these data are included. In particular, we expect the photometric calibrations to differ by of order 0.01 mag.
This note may be cited, but please also cite the SDSS data release paper, Adelman-McCarthy et al. (2006, ApJS, 162, 38), when using the data or referring to the technical documentation. grb@mizar:/home/grb/public_html/private/sdss/GRB060923
GCN Circular #5586
A. Melandri (Liverpool JMU) and A. Gomboc (University of Ljubljana) report on behalf of the RoboNet-1.0 collaboration:
The 2m Faulkes North Telescope (Hawaii) automatically reacted to the Swift burst GRB060923 (trigger 230662, Stamatikos et al. GCN 5583). Observations started 2.8 min after the trigger time. In first images we do not detect any new source brighter than R~19.
Further analysis are ongoing.
GCN Circular #5587
N. Tanvir (U. Leicester), A. Levan (U. Hertfordshire), M. Jarvis (U. Oxford), T. Wold (JACH)
We observed the field of GRB 060923 with UFTI on UKIRT, beginning at 06:07 (UT), approximately 55 minutes post-burst. We detect a faint source in the K-band image at approximately:
```
 16 58 28.18  +12 21 38.9
```
This position (based on provisional astrometry) is only 4.6 arcsec from the reported XRT position (Stamatikos et al. GCN 5583). The source appears to have faded in another (shallower) K-band observation made 30 mins later, and therefore is likely to be the afterglow of this burst.
Further analysis is ongoing.
GCN Circular #5588
G. G. Williams (MMTO) and P. A. Milne (Steward Observatory), on behalf of the Super-LOTIS Collaboration, report:
The robotic 0.6-m Super-LOTIS telescope began observing the error box of GRB 060923 (Swift Trigger 230662, Stamatikos et al. GCN 5583) at 05:12:56.1 UT, 41.1 seconds after the trigger. Our initial observations include 5 x 10s exposures, 5 x 20s exposures, and 30 x 60s exposures, all in the R-band. The observations began at a high airmass of 2.92.
We do not detect any variable sources or afterglow candidates within the XRT error box in our earliest exposure or in the sum of our first five exposures to the following 3-sigma limiting magnitudes determined from nearby USNO-B1.0 stars:
```
t_start (UT)	exp t (s)	t_start-t_0 (s)	Limit
--------------------------------------------------------
05:12:56.1	10.0 		41.1 		R > 16.6 +/- 0.15
05:12:56.1      5 x 10.0        41.1            R > 18.3 +/- 0.15
```
The errors are dominated by scatter in the USNO-B1.0 stars.
GCN Circular #5589
J. Tueller (GSFC) L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU) on behalf of the Swift-BAT team:
Using the data set from T-240 to T+879 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060923 (trigger #230662) (Stamatikos, et al., GCN Circ. 5583). The BAT ground-calculated position is RA,Dec = 254.623, 12.341 deg {16h 58m 29.6s, 12d 20' 28.1"} (J2000) +- 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%.
The burst started with a 6-sec wide peak at T-42 sec. The main peak starts at T-5 sec, peaks at T+1 sec, and ends at T+20 sec. There is a possible third peak at T+19 sec. T90 (15-350 keV) is 51.7 +- 1 sec (estimated error including systematics).
The time-averaged spectrum from T-42.3 to T+11.5 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.69 +- 0.23. The fluence in the 15-150 keV band is 8.7 +- 1.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.03 sec in the 15-150 keV band is 1.3 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #5597
D.B. Fox (Penn State), A. Rau (Caltech), & E.O. Ofek (Caltech) report on behalf of a larger collaboration:
"We have imaged the Swift XRT localization region for GRB060923A (Trigger 230662; Stamatikos et al., GCN 5583) with Keck-I + LRIS (I-band) and Gemini-North + NIRI (J- and K-band). We identify the candidate afterglow of Tanvir et al. (GCN 5587) in our K-band images as the only point source consistent with the XRT localization, with a brightness estimated as follows:
K-band: Ks~20.6 mag at 07:04 UT We estimate its brightness (without correcting for Galactic extinction) by reference to the 2MASS star at R.A. 16:58:31.463, Dec. +12:22:12.88 (J2000), which has J=15.175 mag, H=14.585 mag, and Ks=14.457 mag in that catalog.
The position of the source by reference to NOMAD catalog sources in the vicinity is:
```
    R.A. 16:58:28.15, Dec. +12:21:38.9 (J2000)
```
with an estimated uncertainty of less than 0.5" in each coordinate.
The source is undetected in our earlier J-band and I-band images. Our upper limits on the brightness of the source in these bands are:
```
   I-band:  I>23.5 mag at 06:11 UT
   J-band:  J>23.7 mag at 06:42 UT
```
The I-band photometry is referenced to the SDSS imaging of this field (Cool et al., GCN 5585) while the J-band zero-point is derived from the 2MASS star referenced above. Magnitudes have not been corrected for Galactic extinction.
If this source is the afterglow of GRB060923A, the red colors are suggestive of a highly extinguished or high-redshift burst. In particular, correcting for the Schlegel, Finkbeiner & Davis (1998) estimate of E(B-V)=0.058 mag Galactic extinction, and assuming a temporal decay of t^(-1) and an intrinsic afterglow spectrum of F_nu ~ nu^(-1), these limits indicate suppression of the afterglow flux (relative to K-band) by a factor of >18 at 0.9 micron (I-band) and by a factor of >14 at 1.23 micron (J-band).
GCN Circular #5599
We have analysed the first five orbits of Swift XRT data from GRB 060923A (Stamatikos et al., GCN 5583). A ~2.5ks PC mode image provides a refined X-ray position of:
```
RA(J2000)  =  16h 58m 28.2s
Dec(J2000) = +12d 21' 40.0"
```
with an uncertainty of 6.0 arcseconds radius (90% containment).This is 3.4 arcseconds from the XRT position given by Stamatikos et al.(GCN 5583) and 74.8 arcsec from the refined (ground-calculated) BAT position (Tueller et al., GCN 5589). This position is 1.14 arcseconds from the detected source reported by Tanvir et al. (GCN 5587), and 1.32 arcseconds from the one reported by Fox et al. (GCN 5597) as a candidate counterpart afterglow.
X-ray light curve shows an initial power-law decay with a decay index of 2.7+/-0.3. Then, after a slow rebrightening starting at ~650s, from T+4200 the source decays with a slope of 1.23 +/-0.1.
An absorbed power-law fit to the X-ray spectrum from T+100s to T+960s gave a photon index of 2.1+/-0.2 and a column density of (1.2+/0.1)e21 cm**-2. We note the galactic hydrogen column density in the direction of the burst is 5.1e20 cm**-2. The 0.2-10.0 keV observed flux for this spectrum is 4.1e-11 ergs cm**-2 s**-1, which corresponds to an unabsorbed flux of 4.9e-11 ergs cm**-2 s**-1.
Assuming that the X-ray emission continues to decline at the same rate, we predict a 0.2-10 keV XRT count rate of 0.006 count/s at T+24hr, which corresponds to an observed 0.2-10 keV flux of 2.4e-13 erg/cm**2/s.
This circular is an official product of the Swift XRT Team.
GCN Circular #5605
D.B. Fox (Penn State) reports on behalf of a larger collaboration:
"We have imaged the Swift XRT localization region for GRB060923A (Stamatikos et al., GCN 5583) with Gemini-North + NIRI on a second occasion. The candidate afterglow of Tanvir et al. (GCN 5587) and Fox et al. (GCN 5597) is no longer detected, and we estimate its brightness as:
K-band: Ks>21.5 mag at 05:05 UT, 24 Sep (mean epoch)
using the same photometric calibration as for the previous night (GCN 5597). Fading of the candidate by >~1 mag between our two epochs is separately confirmed in an image subtraction analysis.
This confirms the afterglow nature of the source, and thus the highly reddened, high-redshift and/or highly-extinguished nature of the afterglow of GRB 060923A."
GCN Circular #5620
Dale A. Frail (NRAO) and P. Chandra (NRAO/UVA) report on behalf of a larger collaboration:
"We used the Very Large Array to observe the field of view toward GRB060923A (GCN 5583) at a frequency of 8.46 GHz on 2006 October 26.06 UT. The peak radio brightness at the position of the afterglow of Tanvir et al. (GCN 5587) and Fox et al. (GCN 5597) is -30 uJy +/- 55 uJy. Further observations are planned.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."
GCN Circular #5624
D.B. Fox (Penn State) reports on behalf of a larger collaboration:
"We have activated a sequence of Spitzer Space Telescope IRAC imaging observations of the afterglow of GRB 060923A (Stamatikos et al., GCN 5583). Projected start times for these observations are:
```
   Epoch 1:  10:45 UT on 27 Sep 2006
   Epoch 2:  04:00 UT on 29 Sep 2006 (est.)
   Epoch 3:  15:15 UT on  3 Oct 2006 (est.)
```
Observations for each epoch will last approximately 80 minutes. Observers interested in coordination with Epochs 2 and 3 should contact the author by email in advance to confirm the final schedule."
GCN Circular #5671
P. Chandra (UVA/NRAO) and D. A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward GRB060923A (GCN 5583) at a frequency of 22.5 GHz on 2006 September 30 starting at 19.65 UT. The peak radio brightness at the position of the afterglow of Fox et al. (GCN 5597) is -200 uJy =B1 260 uJy.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."
GCN Circular #5673
A.J. Levan (Hertfordshire), N.R. Tanvir (Leicester), J. Gorosabel (IAA-CSIC) report for a larger collaboration:
We observed the location of GRB 060923A (Tanvir et al. GCN Circ 5587; Fox et al. GCN Circ 5597) in the R-band using the VLT and FORS2. At the location of the afterglow we find a faint, extended source (angular size ~2") with R~25.5. We suggest this is likely to be the host galaxy of GRB 060923A.
If this galaxy is the host of GRB 060923A then its detection in the R-band implies an upper limit for the redshift of z~5. Therefore we believe that extinction is the most likely cause for the extremely red J-K colour for the afterglow at early times.
We that the staff of the VLT for their excellent support.
0803.4100 from 28 Mar 2008 to MNRAS (revised
Tanvir: The extreme, red afterglow of GRB 060923A: Distance or dust?
Abstract: Gamma-ray bursts are powerful probes of the early universe, but locating and identifying very distant GRBs remains challenging. We report here the discovery of the K-band afterglow of Swift GRB 060923A, imaged within the first hour post-burst, and the faintest so far found. It was not detected in any bluer bands to deep limits, making it a candidate very high redshift burst (z>11). However, our later-time optical imaging and spectroscopy reveal a faint galaxy coincident with the GRB position which, if it is the host, implies a more moderate redshift (most likely z<2.8) and therefore that dust is the likely cause of the very red afterglow colour. This being the case, it is one of the few instances so far found of a GRB afterglow with high dust extinction.

Back to JG's homepage

Jochen Greiner, last update: 31-Mar-2008 [Disclaimer]