Gamma-ray Burst 060912

(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 12 Sep 06 13:56:12 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     229185,   Seg_Num: 0
GRB_RA:            5.286d {+00h 21m 09s} (J2000),
                   5.373d {+00h 21m 30s} (current),
                   4.636d {+00h 18m 33s} (1950)
GRB_DEC:         +20.971d {+20d 58' 17"} (J2000),
                 +21.009d {+21d 00' 31"} (current),
                 +20.694d {+20d 41' 39"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       8543 [cnts]    Image_Peak=927 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   147     E_range: 25-100 keV
BKG_INTEN:       30788 [cnts]
BKG_TIME:        50142.56 SOD {13:55:42.56} UT
BKG_DUR:         8 [sec]
GRB_DATE:        13990 TJD;   255 DOY;   06/09/12
GRB_TIME:        50154.14 SOD {13:55:54.14} UT
GRB_PHI:         125.74 [deg]
GRB_THETA:        33.16 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     81.38 [sigma]
IMAGE_SIGNIF:    19.85 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +2 +21  +0  +0 +87  +1 
SUN_POSTN:       170.50d {+11h 22m 00s}   +4.09d {+04d 05' 30"}
SUN_DIST:        150.97 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.37d {+03h 29m 28s}  +23.62d {+23d 37' 25"}
MOON_DIST:        43.36 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.50,-41.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       13.39, 17.11 [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 = 130.78,14.57 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 13:57:54 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.314d {+00h 21m 15s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 13"} (J2000)
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50263.03 SOD {13:57:43.03} UT,   108.9 [sec] since BAT Trigger Time
COUNTS:          5    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    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:     Tue 12 Sep 06 13:59:32 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     229185,   Seg_Num: 0
GRB_RA:            5.286d {+00h 21m 09s} (J2000),
                   5.373d {+00h 21m 30s} (current),
                   4.636d {+00h 18m 33s} (1950)
GRB_DEC:         +20.971d {+20d 58' 17"} (J2000),
                 +21.009d {+21d 00' 31"} (current),
                 +20.694d {+20d 41' 39"} (1950)
GRB_DATE:        13990 TJD;   255 DOY;   06/09/12
GRB_TIME:        50154.14 SOD {13:55:54.14} UT
TRIGGER_INDEX:   147
GRB_PHI:         125.74 [deg]
GRB_THETA:        33.16 [deg]
DELTA_TIME:      -37.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     81.38 [sigma]
IMAGE_SIGNIF:    19.85 [sigma]
LC_URL:          sw00229185000msb.lc
SUN_POSTN:       170.50d {+11h 22m 01s}   +4.09d {+04d 05' 26"}
SUN_DIST:        150.97 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.40d {+03h 29m 36s}  +23.63d {+23d 37' 59"}
MOON_DIST:        43.39 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.50,-41.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       13.39, 17.11 [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 = 130.78,14.57 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 13:59:56 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.314d {+00h 21m 15s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 12"} (J2000)
POINT_ROLL:      31.709d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50267.55 SOD {13:57:47.55} UT,   113.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.508
N_STARS:         37
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0113.fits
SUN_POSTN:       170.50d {+11h 22m 01s}   +4.09d {+04d 05' 26"}
SUN_DIST:        150.93 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.40d {+03h 29m 37s}  +23.63d {+23d 38' 03"}
MOON_DIST:        43.36 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:00:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.314d {+00h 21m 15s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 12"} (J2000)
POINT_ROLL:      31.709d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50267.55 SOD {13:57:47.55} UT,   113.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.508
N_STARS:         37
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0113.fits
SUN_POSTN:       170.50d {+11h 22m 01s}   +4.09d {+04d 05' 25"}
SUN_DIST:        150.93 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.41d {+03h 29m 38s}  +23.64d {+23d 38' 08"}
MOON_DIST:        43.37 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:01:16 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.314d {+00h 21m 15s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 12"} (J2000)
ROLL:            31.709d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50267.55 SOD {13:57:47.55} UT,   113.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179762268
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0113.fits
SUN_POSTN:       170.50d {+11h 22m 01s}   +4.09d {+04d 05' 25"}
SUN_DIST:        150.93 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.42d {+03h 29m 40s}  +23.64d {+23d 38' 16"}
MOON_DIST:        43.37 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:01:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.314d {+00h 21m 15s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 12"} (J2000)
ROLL:            31.709d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50267.55 SOD {13:57:47.55} UT,   113.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179762268
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0113.fits
SUN_POSTN:       170.50d {+11h 22m 01s}   +4.09d {+04d 05' 24"}
SUN_DIST:        150.93 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.42d {+03h 29m 41s}  +23.64d {+23d 38' 19"}
MOON_DIST:        43.38 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:07:17 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
POINT_ROLL:      31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50372.84 SOD {13:59:32.84} UT,   218.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.437
N_STARS:         43
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0218.fits
SUN_POSTN:       170.51d {+11h 22m 02s}   +4.09d {+04d 05' 19"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.48d {+03h 29m 55s}  +23.65d {+23d 39' 18"}
MOON_DIST:        43.43 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:07:35 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
POINT_ROLL:      31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50372.84 SOD {13:59:32.84} UT,   218.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.437
N_STARS:         43
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0218.fits
SUN_POSTN:       170.51d {+11h 22m 02s}   +4.09d {+04d 05' 19"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.48d {+03h 29m 56s}  +23.66d {+23d 39' 21"}
MOON_DIST:        43.43 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:08:30 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
ROLL:            31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50372.84 SOD {13:59:32.84} UT,   218.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179762374
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0218.fits
SUN_POSTN:       170.51d {+11h 22m 02s}   +4.09d {+04d 05' 18"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.49d {+03h 29m 58s}  +23.66d {+23d 39' 30"}
MOON_DIST:        43.44 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:08:51 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
ROLL:            31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50372.84 SOD {13:59:32.84} UT,   218.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179762374
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0218.fits
SUN_POSTN:       170.51d {+11h 22m 02s}   +4.09d {+04d 05' 17"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.49d {+03h 29m 59s}  +23.66d {+23d 39' 33"}
MOON_DIST:        43.44 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:10:39 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     229185,   Seg_Num: 0
GRB_RA:            5.2839d {+00h 21m 08.13s} (J2000),
                   5.3710d {+00h 21m 29.04s} (current),
                   4.6342d {+00h 18m 32.21s} (1950)
GRB_DEC:         +20.9715d {+20d 58' 17.3"} (J2000),
                 +21.0086d {+21d 00' 31.0"} (current),
                 +20.6941d {+20d 41' 38.8"} (1950)
GRB_ERROR:       0.4 [arcsec radius, statistical only]
GRB_MAG:         16.10 +/- 0.50 [mag]
FILTER:          10, White
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50267.00 SOD {13:57:47.00} UT,   112.9 [sec] since BAT Trigger Time
SUN_POSTN:       170.51d {+11h 22m 03s}   +4.09d {+04d 05' 16"}
SUN_DIST:        150.98 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.51d {+03h 30m 03s}  +23.66d {+23d 39' 52"}
MOON_DIST:        43.49 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.49,-41.34 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       13.39, 17.11 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:12:11 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
POINT_ROLL:      31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51012.60 SOD {14:10:12.60} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.527
N_STARS:         38
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0858.fits
SUN_POSTN:       170.51d {+11h 22m 03s}   +4.09d {+04d 05' 14"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.53d {+03h 30m 07s}  +23.67d {+23d 40' 07"}
MOON_DIST:        43.47 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:12:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
POINT_ROLL:      31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51012.60 SOD {14:10:12.60} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.527
N_STARS:         38
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0858.fits
SUN_POSTN:       170.51d {+11h 22m 03s}   +4.09d {+04d 05' 14"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.53d {+03h 30m 08s}  +23.67d {+23d 40' 11"}
MOON_DIST:        43.47 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:13:24 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
ROLL:            31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51012.60 SOD {14:10:12.60} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179763014
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0858.fits
SUN_POSTN:       170.51d {+11h 22m 03s}   +4.09d {+04d 05' 13"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.54d {+03h 30m 10s}  +23.67d {+23d 40' 20"}
MOON_DIST:        43.48 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:13:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 09"} (J2000)
ROLL:            31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51012.60 SOD {14:10:12.60} UT,   858.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179763014
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0858.fits
SUN_POSTN:       170.51d {+11h 22m 03s}   +4.09d {+04d 05' 13"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.54d {+03h 30m 10s}  +23.67d {+23d 40' 22"}
MOON_DIST:        43.48 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:18:56 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 10"} (J2000)
POINT_ROLL:      31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51117.84 SOD {14:11:57.84} UT,   963.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.428
N_STARS:         41
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0963.fits
SUN_POSTN:       170.52d {+11h 22m 04s}   +4.09d {+04d 05' 08"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.60d {+03h 30m 23s}  +23.69d {+23d 41' 16"}
MOON_DIST:        43.53 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:19:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 10"} (J2000)
POINT_ROLL:      31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51117.84 SOD {14:11:57.84} UT,   963.7 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.428
N_STARS:         41
X_OFFSET:        189 [pixels]
Y_OFFSET:        651 [pixels]
X_MAX:           1148 [pixels]
Y_MAX:           1610 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00229185000msufc0963.fits
SUN_POSTN:       170.52d {+11h 22m 04s}   +4.09d {+04d 05' 07"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.60d {+03h 30m 24s}  +23.69d {+23d 41' 20"}
MOON_DIST:        43.53 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:20:09 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 10"} (J2000)
ROLL:            31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51117.84 SOD {14:11:57.84} UT,   963.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179763119
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0963.fits
SUN_POSTN:       170.52d {+11h 22m 04s}   +4.09d {+04d 05' 07"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.61d {+03h 30m 26s}  +23.69d {+23d 41' 28"}
MOON_DIST:        43.54 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 12 Sep 06 14:20:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     229185,   Seg_Num: 0
POINT_RA:          5.316d {+00h 21m 16s} (J2000)
POINT_DEC:       +21.003d {+21d 00' 10"} (J2000)
ROLL:            31.712d
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  51117.84 SOD {14:11:57.84} UT,   963.7 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179763119
X_OFFSET:        508 [pixels]
Y_OFFSET:        970 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       668
Y_GRB_POS:       1130
BINNING_INDEX:   1
IM_URL:          sw00229185000msuni0963.fits
SUN_POSTN:       170.52d {+11h 22m 04s}   +4.09d {+04d 05' 06"}
SUN_DIST:        150.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.61d {+03h 30m 27s}  +23.69d {+23d 41' 31"}
MOON_DIST:        43.54 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.54,-41.32 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       13.43, 17.12 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 12 Sep 06 14:23:53 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     229185,   Seg_Num: 0
GRB_RA:            5.2842d {+00h 21m 08.2s} (J2000),
                   5.3713d {+00h 21m 29.1s} (current),
                   4.6345d {+00h 18m 32.2s} (1950)
GRB_DEC:         +20.9718d {+20d 58' 18.4"} (J2000),
                 +21.0089d {+21d 00' 32.1"} (current),
                 +20.6944d {+20d 41' 39.9"} (1950)
GRB_ERROR:       3.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.00 [sigma]
IMG_START_DATE:  13990 TJD;   255 DOY;   06/09/12
IMG_START_TIME:  50263.02 SOD {13:57:43.02} UT,   108.9 [sec] since BAT Trigger Time
TAM[0-3]:        327.61 237.19 261.35 242.66
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       170.52d {+11h 22m 04s}   +4.08d {+04d 05' 03"}
SUN_DIST:        150.99 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:       52.65d {+03h 30m 35s}  +23.70d {+23d 42' 06"}
MOON_DIST:        43.61 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      113.50,-41.34 [deg] galactic lon,lat of the burst
ECL_COORDS:       13.39, 17.11 [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 #5558
C. P. Hurkett (U Leicester), S. D. Barthelmy (GSFC), P. J. Brown (PSU), D. N. Burrows (PSU), M. M. Chester (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), C. Guidorzi (Univ Bicocca&INAF-OAB), S. T. Holland (GSFC/USRA), S. Immler (GSFC/USRA), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), F. E. Marshall (NASA/GSFC), K. M. McLean (LANL/UTD), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC), P. Romano (INAF-OAB), T. Sakamoto (NASA/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (NASA/ORAU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 13:55:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060912 (trigger=229185). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 5.286, +20.971 {00h 21m 09s, +20d 58' 17"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single FRED-like peak (FWHM ~3 sec) with a total duration of about 7 sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~1 sec after the trigger. We note that the spectrum is hard and the main emission is confined to ~3 sec. It is possible that the burst is short, although it appears with existing data to be long. A lag analysis will be done with the event data in ~3 hours.
The XRT began taking data at 13:57:43 UT, 109 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image but ground analysis of flight data reveals a fading source at Ra, Dec 00h 21m 08.2 +20 58 18.6 (J2000), with an uncertainty of 3.9" (radius, 90% containment). This is 7 arcseconds from the BAT position and 1 arcsecond from the UVOT position.
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 113 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 00:21:08.16 (5.2840) DEC(J2000) = +20:58:17.8 (20.9716) with a 1-sigma error radius of about 0.5 arc sec. This position is 7.0 arc sec. from the center of the BAT error circle. The estimated magnitude is 16.1 with a 1-sigma error of about 0.5 mag. The afterglow fades to about 18th magnitude in the subsequent white finding chart. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05.
We note that there is a 2MASS galaxy in the Hyperleda catalog at 00:21:08.6 20:58:08 (PGC # 1639821), 11.5 arc sec from the UVOT position. The diameter of the galaxy is 0.36 arcmin.

GCN Circular #5559
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GCN Circular #5560: Correction to GCN 5559
M.Zhai, L.P. Xing, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng, Y. Urata and W.K. Zheng, on behalf of EAFON report:
We have imaged the field of GRB 060912 with the TNT 0.8m telescope at Xinglong Observatory.The first image was taken at 13:57:23 UT, 89s after the burst. The optical counterpart (Hurkett et al. GCN 5558) were well detected in our clear and R band images.Preliminary analysis shows the OT fade to ~19 about 35 minutes after the burst in our white images. We encourage deeper observation. Further analysis is under progress.
This message may be cited.
We apologize for the mistake about the character format.
GCN Circular #5561
A. Parsons (GSFC), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMD), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), C. P. Hurkett (U Leicester), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), J. Norris (GSFC), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-120 to T+183 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060912 (trigger #229185) (Hurkett, et al., GCN Circ. 5558). The BAT ground-calculated position is RA,Dec = 5.286,+20.971 deg {0h 21m 8.7s,+20d 58' 16.3"} (J2000) +- 0.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%.
The mask-weighted lightcurve has a single peak with a faster rise than decay. T90 (15-350 keV) is 5.0 +- 0.5 sec (estimated error including systematics).
The time-averaged spectrum from T-0.6 to T+6.1 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.74 +- 0.09. The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.02 sec in the 15-150 keV band is 8.5 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The spectral lag calculation (Norris & Bonnell, ApJ, 2006) shows this burst to be clearly in the long-burst class. The lag is 190 +28 -40 ms between the 15-25 and 50-100 keV bands and 83 +43 -43 ms between the 25-50 and 100-350 bands.
GCN Circular #5562
C. P. Hurkett, K.L. Page and E. Rol (U Leicester) report on behalf of the Swift XRT team:
We have analysed the Swift XRT data from the first orbit observation of GRB 060912 (Hurkett et al., GCN 5558), with a total exposure of 1.7 ks seconds. The refined XRT position is:
```
   RA(J2000) =  00 21 08.23
  Dec(J2000) = +20 58 15.8
```
This position is 10.9 arcseconds from the BAT position given in GCN 5558 (Hurkett et al. 2006), 2.8 arcseconds from the XRT position and 2.0 arcseconds from the UVOT given in the same GCN. We estimate an uncertainty of 3.6 arcseconds radius (90% containment).
The 0.3-10.0 keV Photon Counting (PC) mode starts 135 seconds after the BAT trigger (T0). The count rate is declining with a decay slope of 0.62 (+/-0.12).
A preliminary spectral fit to the PC data gives a spectral power law photon index of 2.08 +/- 0.20 in the [0.3-10] keV band, with a free absorption of 0.17 (+/- 0.06)e22 cm^-2 (Galactic absorption at this location is 4.20e20 cm^-2). The average (in the time range 135-1860 seconds from trigger) estimated unabsorbed 0.3-10 keV flux is then about 2.9E-11 erg/cm2/s.
The XRT count rate extrapolated to T0+24 hr is estimated to be about 0.025 cps, corresponding to an unabsorbed 0.3-10 keV flux of about 1.73E-12 erg/cm2/s.
This Circular is an official product of the Swift XRT Team.
GCN Circular #5564
A. Stefanescu, F. Schrey, S. Duscha, M. Muehlegger, N. Primak, G. Kanbach, H. Steinle (MPE Garching) of the OPTIMA-Burst Team report the following:
"OPTIMA-Burst at the 1.3m Skinakas Observatory, of the University of Crete, Greece observed the Swift XRT-errorcircle of GRB 060912 (GCN Circ. 5558, C.P. Hurkett et al.) starting at 19:21UT (~5.5h after the Burst).
We detect a source consistent with the source reported by C.P. Hurkett et al. and M. Zhai et al. (GCN Circ. 5560). We estimate the magnitude of the source as R=21.6 +- 0.2
There is no known minor planet brighter than 23 mag within 5' of the source according to MPChecker"
GCN Circular #5565
P. J. Brown (PSU) & C. P. Hurkett (U Leicester) report on behalf of the Swift UVOT team:
Swift/UVOT began settled observations of GRB060912 (BAT trigger 229185) at 13:57:47 UT, 113 seconds after the initial Swift BAT trigger (Hurkett et al., GCN Circ. 5558). The fading optical counterpart seen in the white finding charts was also detected by UVOT in V, B, U, UVW1 and marginally in UVM2. The relatively shallow upper limit in UVW2 prevents us from constraining the redshift well.
The magnitudes from early observations and the upper limit in UVW2 are tabulated below.
```
Filter  T_range(s)    Exp(s)     Magnitude

White   113-212       100        16.0 +/- 0.1
White   859-958       100        18.1 +/- 0.1

V       219-618       400        17.4 +/- 0.1
V       964-1363      400        18.4 +/- 0.2

B       697-1776      79         19.5 +/- 0.4

U       672-691       20         17.6 +/- 0.2

UVW1    649-668       20         18.51 +/- 0.4

UVM2    624-1861      119        19.3 +/- 0.4

UVW2    725-1814      78       > 19.5 (3.0-sigma)
```
T_range is the span of the exposure in seconds from the BAT trigger.
The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)=0.05.
GCN Circular #5567
B. Hafizov, M. Ibrahimov (MAO), A. Pozanenko (IKI), on behalf of larger GRB follow up collaboration report:
We observed the afterglow of GRB060912 (Hurkett et al. GCN 5558) with 1.5m telescope of Maidanak Astronomical Observatory (MAO) in BR-bands on September 12 between (UT) 17:25 and 19:30. The afterglow candidate (Hurkett et al. GCN 5558, Zhai et al. GCN 5560) is detected on a single 120 s images. Preliminary photometry of the optical transient in R-band at Sep. 12 17:30 (UT) is R~20.5m.
GCN Circular #5568
E. Berger (Carnegie Observatories) reports on behalf of a larger collaboration:
"Starting on 2006 Sep. 13.22 UT we used GMOS on Gemini-South to obtain an 1800 sec spectrum of the bright 2MASS galaxy located 11" away from the optical afterglow position of GRB 060912 (GCN 5558), at a position angle that also included the afterglow position. The spectrum of the 2MASS galaxy it typical of an early-type galaxy with CaII H&K, Mg b, and Na D absorption features at a redshift, z=0.0936. At the position of the afterglow we do not detect any clear continuum emission or emission lines (4000-7000 A). If the 2MASS galaxy is in fact the host galaxy of GRB 060912, then the isotropic-equivalent gamma-ray energy is only 2.6e49 erg. Moreover, the nature of the host galaxy would suggest that the GRB is most likely to be a short burst. Deep imaging observations to search for a faint galaxy at the position of the afterglow are planned."
GCN Circular #5570
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report:
The GRB 060912 (Swift-BAT trigger 229185, GCN 5558) triggered Konus-Wind at 50157.788 s UT (13:55:57.788). As observed by Konus-Wind, it had a duration of ~8 s. Its spectrum is well fitted by a power law model in the energy range 20 keV - 2 MeV, with alpha = -1.94 +/- 0.2 for time interval T0 - (T0 + 8s).
The burst fluence is ~4x10-6 erg/cm2 and the 256-ms peak flux is 1.8x10-6 erg/cm2 s (both in the 20 keV - 2 MeV energy range).
GCN Circular #5573
A.J. Levan, P. Jakobsson, R. Chapman (U. Hertfordshire), N. Tanvir, E.Rol (U. Leicester) report for a larger collaboration:
We observed the location of GRB 050912A using the VLT and FORS1 in the VRI bands beginning at Sept 14. 03:51 UT. At the location of the optical afterglow given by Hurkett et al. (GCN Circ. 5558) we find an extended source which we suggest is the host galaxy of GRB 060912A. The location of the afterglow lies at the eastern end of this galaxy and the afterglow may still contribute significantly at this time.
Images of the field can be found at
http://star-www.herts.ac.uk/~levan/060912A/
We thank the staff of the VLT for their assistance with these observations.
GCN Circular #5574
P. Chandra (UVA/NRAO) and D. A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration:
"We observed the field centered on the BAT position of the Swift burst GRB 060912A (GCN#5562) using the VLA at a frequency of 8.46 GHz and starting at 8.19 UT on September 14, 2006. There is no detection of the GRB with 2-sigma upper limit of 65 microJy.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."
GCN Circular #5617
GRB 060912A: Redshift of probable host galaxy
P. Jakobsson, A. Levan, R. Chapman (U. Hertfordshire), E. Rol, N. Tanvir (U. Leicester), P. Vreeswijk (ESO), D. Watson (DARK, NBI)
We obtained 6*1200 s spectra of the proposed host galaxy of GRB 060912A (Levan et al. GCN 5573), using FORS2 on the VLT. The combined spectrum shows a very strong emission line at 7218A which we identify with [OII] 3727A at a redshift of z = 0.937. At the same redshift we also identify H-gamma in emission and possibly NeIII 3869A. The properties of this host galaxy (in particular strong [OII] emission) are similar to those seen in long-duration GRB hosts. We conclude that the proximity of this burst to a low redshift elliptical galaxy was most likely coincidental.
We thank the VLT staff for their assistance in these observations.
A case of mistaken identity? GRB060912A and the nature of the long-short GRB divide, MN 378 (2007) 1439
Abstract: We investigate the origin of the GRB060912A, which has observational properties that make its classification as either a long or short burst ambiguous. Short-duration gamma-ray bursts (SGRBs) are thought to have typically lower energies than long-duration bursts, can be found in galaxies with populations of all ages and are likely to originate from different progenitors to the long-duration bursts. However, it has become clear that duration alone is insufficient to make a distinction between the two populations in many cases, leading to a desire to find additional discriminators of burst type. GRB060912A had a duration of 6s and occurred only ~10arcsec from a bright, low-redshift (z = 0.0936) elliptical galaxy, suggesting that this may have been the host, which would favour it being a short burst. However, our deep optical imaging and spectroscopy of the location of GRB060912A using the Very Large Telescope (VLT) shows that GRB060912A more likely originates in a distant star-forming galaxy at z = 0.937, and is most likely a long burst. This demonstrates the risk in identifying bright, nearby galaxies as the hosts of given gamma-ray bursts (GRBs) without further supporting evidence. Further, it implies that, in the absence of secure identifications, `host' type, or more broadly discriminators that rely on galaxy redshifts, may not be good indicators of the true nature of any given GRB.

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Jochen Greiner, last update: 18-Apr-2008 [Disclaimer]