Gamma-ray Burst 060906

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:34:06 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     228316,   Seg_Num: 0
GRB_RA:           40.748d {+02h 42m 60s} (J2000),
                  40.848d {+02h 43m 24s} (current),
                  40.003d {+02h 40m 01s} (1950)
GRB_DEC:         +30.349d {+30d 20' 58"} (J2000),
                 +30.378d {+30d 22' 39"} (current),
                 +30.137d {+30d 08' 14"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1462 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        13984 TJD;   249 DOY;   06/09/06
GRB_TIME:        30766.57 SOD {08:32:46.57} UT
GRB_PHI:         152.19 [deg]
GRB_THETA:        35.27 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.96 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -2  +0  +0 +42  +1 
SUN_POSTN:       164.91d {+10h 59m 37s}   +6.44d {+06d 26' 25"}
SUN_DIST:        115.05 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.62d {+21h 46m 29s}  -16.32d {-16d 19' 20"}
MOON_DIST:        85.24 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.78,-26.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       47.67, 13.86 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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 = 235.12,6.94 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:49:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
POINT_ROLL:      65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31626.41 SOD {08:47:06.41} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.846
N_STARS:         147
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00228316000msufc0859.fits
SUN_POSTN:       164.92d {+10h 59m 40s}   +6.44d {+06d 26' 11"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.77d {+21h 47m 06s}  -16.26d {-16d 15' 29"}
MOON_DIST:        85.11 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:35:24 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.766d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.363d {+30d 21' 49"} (J2000)
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  30915.08 SOD {08:35:15.08} UT,   148.5 [sec] since BAT Trigger Time
COUNTS:          10    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:     Wed 06 Sep 06 08:44:38 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
POINT_ROLL:      65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31023.36 SOD {08:37:03.36} UT,   256.8 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.747
N_STARS:         161
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00228316000msufc0256.fits
SUN_POSTN:       164.91d {+10h 59m 39s}   +6.44d {+06d 26' 15"}
SUN_DIST:        115.03 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.73d {+21h 46m 55s}  -16.28d {-16d 16' 41"}
MOON_DIST:        85.15 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:49:05 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
POINT_ROLL:      65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31626.41 SOD {08:47:06.41} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.846
N_STARS:         147
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00228316000msufc0859.fits
SUN_POSTN:       164.92d {+10h 59m 40s}   +6.44d {+06d 26' 11"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.77d {+21h 47m 05s}  -16.26d {-16d 15' 34"}
MOON_DIST:        85.11 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:38:53 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.766d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.363d {+30d 21' 48"} (J2000)
ROLL:            65.243d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  30918.08 SOD {08:35:18.08} UT,   151.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179224519
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0151.fits
SUN_POSTN:       164.91d {+10h 59m 38s}   +6.44d {+06d 26' 21"}
SUN_DIST:        115.03 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.67d {+21h 46m 41s}  -16.30d {-16d 18' 08"}
MOON_DIST:        85.21 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.87 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:50:25 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
ROLL:            65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31626.41 SOD {08:47:06.41} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179225227
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0859.fits
SUN_POSTN:       164.92d {+10h 59m 40s}   +6.44d {+06d 26' 10"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.78d {+21h 47m 08s}  -16.25d {-16d 15' 13"}
MOON_DIST:        85.09 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [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:     Wed 06 Sep 06 08:50:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
ROLL:            65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31626.41 SOD {08:47:06.41} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179225227
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0859.fits
SUN_POSTN:       164.92d {+10h 59m 40s}   +6.44d {+06d 26' 10"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.79d {+21h 47m 09s}  -16.25d {-16d 15' 10"}
MOON_DIST:        85.09 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:36:38 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     228316,   Seg_Num: 0
GRB_RA:           40.748d {+02h 42m 60s} (J2000),
                  40.848d {+02h 43m 24s} (current),
                  40.003d {+02h 40m 01s} (1950)
GRB_DEC:         +30.349d {+30d 20' 58"} (J2000),
                 +30.378d {+30d 22' 39"} (current),
                 +30.137d {+30d 08' 14"} (1950)
GRB_DATE:        13984 TJD;   249 DOY;   06/09/06
GRB_TIME:        30766.57 SOD {08:32:46.57} UT
TRIGGER_INDEX:   20000
GRB_PHI:         152.19 [deg]
GRB_THETA:        35.27 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.96 [sigma]
LC_URL:          sw00228316000msb.lc
SUN_POSTN:       164.91d {+10h 59m 38s}   +6.44d {+06d 26' 23"}
SUN_DIST:        115.05 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.65d {+21h 46m 36s}  -16.31d {-16d 18' 42"}
MOON_DIST:        85.22 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.78,-26.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       47.67, 13.86 [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 an image 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 = 235.12,6.94 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:38:42 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.766d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.363d {+30d 21' 48"} (J2000)
ROLL:            65.243d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  30918.08 SOD {08:35:18.08} UT,   151.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     179224519
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0151.fits
SUN_POSTN:       164.91d {+10h 59m 38s}   +6.44d {+06d 26' 21"}
SUN_DIST:        115.03 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.67d {+21h 46m 40s}  -16.30d {-16d 18' 10"}
MOON_DIST:        85.21 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.87 [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:     Wed 06 Sep 06 08:46:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
ROLL:            65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31023.36 SOD {08:37:03.36} UT,   256.8 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179224624
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0256.fits
SUN_POSTN:       164.91d {+10h 59m 39s}   +6.44d {+06d 26' 14"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.74d {+21h 46m 58s}  -16.27d {-16d 16' 17"}
MOON_DIST:        85.14 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:44:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
POINT_ROLL:      65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31023.36 SOD {08:37:03.36} UT,   256.8 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.747
N_STARS:         161
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00228316000msufc0256.fits
SUN_POSTN:       164.91d {+10h 59m 39s}   +6.44d {+06d 26' 15"}
SUN_DIST:        115.03 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.73d {+21h 46m 55s}  -16.28d {-16d 16' 36"}
MOON_DIST:        85.15 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:37:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.766d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.363d {+30d 21' 48"} (J2000)
POINT_ROLL:      65.243d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  30918.08 SOD {08:35:18.08} UT,   151.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.800
N_STARS:         117
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00228316000msufc0151.fits
SUN_POSTN:       164.91d {+10h 59m 38s}   +6.44d {+06d 26' 22"}
SUN_DIST:        115.03 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.66d {+21h 46m 38s}  -16.31d {-16d 18' 27"}
MOON_DIST:        85.22 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.87 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:37:19 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.766d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.363d {+30d 21' 48"} (J2000)
POINT_ROLL:      65.243d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  30918.08 SOD {08:35:18.08} UT,   151.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.800
N_STARS:         117
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00228316000msufc0151.fits
SUN_POSTN:       164.91d {+10h 59m 38s}   +6.44d {+06d 26' 22"}
SUN_DIST:        115.03 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.65d {+21h 46m 37s}  -16.31d {-16d 18' 31"}
MOON_DIST:        85.23 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.87 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:45:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.361d {+30d 21' 41"} (J2000)
ROLL:            65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31023.36 SOD {08:37:03.36} UT,   256.8 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179224624
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0256.fits
SUN_POSTN:       164.91d {+10h 59m 39s}   +6.44d {+06d 26' 14"}
SUN_DIST:        115.03 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.74d {+21h 46m 58s}  -16.27d {-16d 16' 21"}
MOON_DIST:        85.14 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [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:     Wed 06 Sep 06 08:55:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.362d {+30d 21' 42"} (J2000)
POINT_ROLL:      65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31731.64 SOD {08:48:51.64} UT,   965.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.703
N_STARS:         140
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00228316000msufc0965.fits
SUN_POSTN:       164.92d {+10h 59m 41s}   +6.43d {+06d 26' 05"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.84d {+21h 47m 21s}  -16.23d {-16d 13' 51"}
MOON_DIST:        85.04 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:56:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.362d {+30d 21' 42"} (J2000)
POINT_ROLL:      65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31731.64 SOD {08:48:51.64} UT,   965.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.703
N_STARS:         140
X_OFFSET:        361 [pixels]
Y_OFFSET:        652 [pixels]
X_MAX:           1320 [pixels]
Y_MAX:           1611 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00228316000msufc0965.fits
SUN_POSTN:       164.92d {+10h 59m 41s}   +6.43d {+06d 26' 05"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.84d {+21h 47m 22s}  -16.23d {-16d 13' 46"}
MOON_DIST:        85.04 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 06 Sep 06 08:57:10 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.362d {+30d 21' 42"} (J2000)
ROLL:            65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31731.64 SOD {08:48:51.64} UT,   965.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179225333
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0965.fits
SUN_POSTN:       164.92d {+10h 59m 41s}   +6.43d {+06d 26' 04"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.85d {+21h 47m 24s}  -16.23d {-16d 13' 31"}
MOON_DIST:        85.03 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [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:     Wed 06 Sep 06 08:57:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     228316,   Seg_Num: 0
POINT_RA:         40.768d {+02h 43m 04s} (J2000)
POINT_DEC:       +30.362d {+30d 21' 42"} (J2000)
ROLL:            65.245d
IMG_START_DATE:  13984 TJD;   249 DOY;   06/09/06
IMG_START_TIME:  31731.64 SOD {08:48:51.64} UT,   965.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     179225333
X_OFFSET:        680 [pixels]
Y_OFFSET:        971 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       840
Y_GRB_POS:       1131
BINNING_INDEX:   1
IM_URL:          sw00228316000msuni0965.fits
SUN_POSTN:       164.92d {+10h 59m 41s}   +6.43d {+06d 26' 03"}
SUN_DIST:        115.04 [deg]   Sun_angle= 8.3 [hr] (West of Sun)
MOON_POSTN:      326.85d {+21h 47m 25s}  -16.22d {-16d 13' 28"}
MOON_DIST:        85.02 [deg]
MOON_ILLUM:      97 [%]
GAL_COORDS:      149.79,-26.62 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       47.69, 13.86 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #5528
J. L. Racusin (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), C. Guidorzi (Univ Bicocca&INAF-OAB), S. D. Hunsberger (PSU), V. Mangano (INAF-IASFPA), D. C. Morris (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), E. Rol (U Leicester), P. Romano (INAF-OAB), G. Sato (GSFC/ISAS), M. Stamatikos (NASA/ORAU) and H. Z. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team:
At 08:32:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060906 (trigger=228316). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 40.748, +30.349 {02h 42m 60s, +30d 20' 58"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is complicated by the fact that the spacecraft was slewing just prior to the image trigger. There appears to be an ~5 sec wide peak starting at T_zero. There are possibly two smaller peaks at T-15 and T-21 sec, but these are during the slew and may be caused by the slew. The peak count rate is ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began taking data at 08:35:15 UT, 148 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image but ground analysis of 5 seconds of flight data available at this time reveals a possible faint source at the following coordinates:
```
RA(J2000): 2h 43m 00.9s
Dec(J2000): +30 21 38.95   
```
with an error of 8 arcseconds (90% confidence). Further analysis of ground data is necessary to determine the properties of the possible source.
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 152 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 18.5 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT 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 0.20.
We will have the full data set downlinked and processed by ~11:00 UT.
GCN Circular #5529
S. B. Cenko, E. O. Ofek (Caltech) and D. B. Fox (Penn State) report on behalf of a larger collaboration:
We have imaged the field of Swift trigger 228316 (GRB 060906?) with the automated Palomar 60-inch telescope. Observations were taken in the Kron R filter beginning approximately 12 minutes after the burst. Inside the BAT error circle, we find a stationary object not present in the Digitized Sky Survey at the location (J2000.0):
```
	RA: 02:43:00.9
	Dec: +30:21:42.12
```
We estimate the magnitude of the object to be R ~ 19.0, based on comparison with several USNO-B objects in the field. Given the brightness and stationary nature of the object, we consider it a possible optical afterglow. Further observations are underway to search for variability.
GCN Circular #5530
P. Kubanek (AsU AV CR Ondrejov & ISDC Versoix) and M.Prouza (FZU Praha, UC NY) reports on behalf of the FRAM collaboration:
We observed location of GRB 060906 (GCN Circ. 5528, S. Barthelmy et al.) with FRAM telescope at Pierre Auger Observatory, Argentina. Inside XRT error circle, in R band single image, we detected bright flash at location:
02:42:49.5 +30:24:21.7 (J2000)
Object is not present in DSS images, nor in USNO catalogue.
WE WARN THAT THIS OBJECT IS MOST PROBABLY ARTIFACT FROM CAMERA SHUTTER FAILURE. At present time, we are unsure about nature of that event. We kindly request observers with all-sky cameras to check for that object.
Finding chart is available at:
http://lascaux.asu.cas.cz/~petr/20060906.png
Bigger circle is XRT location, smaller is OT candidate (GCN Circ. 5529, S. Bradley Cenko et al.) and object mentioned above. First image is 20 sec R band exposure starting at 08:34:53 (125 sec post GRB), second is 20 sec starting at 08:35:20. Object is not visible at second image. Line going from object down is in image Y axis direction, so it might be a object bloom.
Futher observations, as well as analysis, are in progress.
GCN Circular #5531
S. B. Cenko (Caltech) reports on behalf of a larger collaboration:
We have continued to image the field of GRB060906 (Racusin et al; GCN 5528) with the automated Palomar 60-inch telescope. Our observations indicate the candidate identified by Cenko, Ofek and Fox (GCN 5529) has faded and is therefore the optical afterglow of GRB060906. In particular, the object faded by ~ 0.9 mag in R-band images taken 11 min and 53 min after the burst, corresponding to a shallow power-law decay index (t ^ -0.5).
GCN Circular #5532
W. Li and J. Bloom (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 060906, detected with Swift (Trigger 228316; Racusin et al. GCN 5528). The automatic sequence started at 08:34:32, 106 s after the burst. In a 15 s unfiltered image, no afterglow candidate is detected to a limiting magnitude of 18.2 (from comparison with the USNO B1.0 catalog). We detected the optical afterglow reported by Cenko et al. (GCN 5529, 5531) in a 45 s unfiltered image started at 336 s after the burst, with the following precise (+/- 0.2") position:
RA = 2:43:00.84 Dec = +39:21:41.9 (J2000.)
A table of photometry (3-sigma limits and detections) is reported below.
```
======================================================================

Start UT   t(GRB)   Filter    Exp(s)  3sigma-limit       detection 

08:34:32    106s    clear     15.0     <18.2
08:35:07    141s    V         15.0     <16.7
08:35:33    167s    I         15.0     <17.5
08:35:59    193s    clear     20.0     <18.4
08:36:30    224s    V         45.0     <17.3
08:37:27    281s    I         45.0     <18.3
08:38:22    336s    clear     45.0                          18.9 +/- 0.3

========================================================================
```
GCN Circular #5533
P.Kubanek (AsU AV CR Ondrejov, ISDC Versoix) reports:
The object mentioned in GCN Circ.5530 is:
```
- outside XRT and BAT location
- show second object roughly 10 arcmin apart (~27m @ 10km)
```
so it is most probably airplane. This object is not related to GRB 060906.
I apologize for error in position determination - I forget to switch from BAT arcmin error box to XRT arcsec error box when I plot localizations. I thank to S.B.Cenko for pointing that out.
GCN Circular #5534
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMD), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), J.L. Racusin (PSU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-119 to T+183 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060906 (trigger #228316) (Racusin, et al., GCN Circ. 5528). The BAT ground-calculated position is RA,Dec = 40.710, 30.356 deg {2h 42m 50.4s, 30d 21' 21.3"} (J2000) +- 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 45%.
This burst started at ~T-50 sec while the spacecraft was still slewing between regularly scheduled follow-up targets. The initial emission is a broad peak of roughly constant flux. It returns to background level at ~T-4 sec and then the peak which BAT actually triggerred on starts. It peaks at T~T+4 sec at a level about half of the initial broad peak. T90 (15-350 keV) is 43.6 +- 1 sec (estimated error including systematics).
Because most of the burst happened during slewing, our standard processing for the spectral, flux, and fluence results are not appropriate. We will issue another circular with those results when they become available.
GCN Circular #5535
Paul Vreeswijk (ESO/Cerro Calan), Pall Jakobsson (Hertfordshire), Cedric Ledoux (ESO), Christina Thoene, Johan Fynbo (DARK) report on behalf of a larger collaboration:
We observed the optical afterglow (Cenko et al., GCN 5529) of GRB 060906 detected by Swift (Racusin et al., GCN 5528) with ESO's Very Large Telescope UT2 (Kueyen) at Paranal, Chile. One single FORS1 spectrum with an exposure time of 10min. was taken in twilight, with the 300V grism and a 1" slit, providing a wavelength coverage of 3800-8900 at a resolution of 12 A.
We detect a damped Ly alpha line and various other absorption features such as Si II, Si II*, O I, C II, Si IV at a redshift of z=3.685.
It's a pleasure to thank the excellent support of the Paranal staff, and in particular that of Claudio Melo, Chris Lidman and Linda Schmidtobreick.
GCN Circular #5536
P. Schady (MSSL-UCL) and J.L. Racusin (PSU) report on behalf of the Swift-UVOT team:
The Swift UVOT began observing GRB 060906 152 seconds after the BAT trigger (GCN 5528). No optical afterglow is detected at the 3-sigma level in the XRT error circle (GCN 5528) or at the location of the afterglow reported by Cenko et al. (GCN 5529) in individual or coadded exposures of any of the UVOT filters.
The 3-sigma limiting magnitudes for the coadded images of the UVOT filters are listed below:
```
Filter  T_range(s)      Exp(s)  Upper limit (3sig)
WHITE   201-8121        583     20.6
V       457-7210        1297    20.1
B       739-8029        520     20.3
U       720-7824        529     20.0
W1      697-7619        549     19.6
M2      672-7415        549     19.9
W2      773-7006        320     19.7
```
where T_range is the start and end times of the coadded exposures. No correction has been made for Galactic reddening along the line of sight (E(B-V) = 0.20 mag).
GCN Circular #5537
J. L. Racusin, D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), D. Grupe, J. A. Kennea (PSU) report on behalf of the Swift XRT team:
We have analysed the Swift-XRT data from the first 6 orbits of GRB 060906 (Racusin et al., GCN Circ. 5528), with a total exposure of 12200 seconds. The refined XRT position is:
```
RA(J2000): 2h 43m 00.66s
Dec(J2000): +30d 21' 37.82"
```
with an uncertainty of 4 arcseconds (90% containment). This position is 134 arcseconds from the refined BAT position given in GCN Circ. 5534 (Sakamoto et al.), 3.3 arcseconds from the XRT position given in GCN 5528, and 5.3 arcseconds from the optical counterpart reported by Cenko et al. (GCN 5529).
The light-curve starts 153 seconds after the BAT trigger and shows a steep decline with a decay index of -3.4 +/- 1.3 followed by a flattening at ~400 seconds described by a power-law with index -0.2 +/- 0.1, and breaking again at ~11000 seconds to a power-law index of -1.7 +/- 0.3.
A preliminary spectral fit to the WT data gives a spectral power law photon index of 2.5 +/- 0.5 in the [0.3-10] keV band, with absorption column density consistent with the Galactic value (9.66e20 cm^-2). The average (in the time range 153-776 seconds from trigger) estimated unabsorbed 0.3-10 keV flux was 1.37e-11 erg cm^-2 s^-1.
The XRT count rate extrapolated to T+24 hr is estimated to be about 0.002 counts/s, corresponding to an unabsorbed 0.3-10 keV flux of about 1.72e-13 erg cm^-2 s^-1.
This Circular is an official product of the Swift XRT Team.
GCN Circular #5538
G. Sato (GSFC/ISAS), T. Sakamoto (GSFC/ORAU), C. Markwardt (GSFC/UMD), D. Palmer (LANL), S. D. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/UMD), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), A. Parsons (GSFC), J.L. Racusin (PSU), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC) on behalf of the Swift-BAT team:
We report the spectral analysis of Swift-BAT GRB 060906 (trigger #228316) (Racusin, et al., GCN Circ. 5528; & Sakamoto, et al., GCN Circ. 5534). Using the response matrix appropriate for the burst position in the BAT field-of-view during the slew: The time-averaged spectrum from T-41.8 to T+6.0 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.02 +- 0.11. The fluence in the 15-150 keV band is 2.21 +- 0.14 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-24.86 sec in the 15-150 keV band is 2.0 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #5539
J. Wren, W.T. Vestrand, P.R. Wozniak, R. White, S. Evans, and J. Pergande of Los Alamos National Laboratory report:
The RAPTOR array of telescopes autonomously responded to Swift trigger 228316. Conditions were cloudy at our primary telescope site but our wide-field RAPTOR-B small telescope array, located at our secondary site, imaged the event under clear conditions. Imaging began at 08:34:12.53 UTC (86.0 s after the trigger, 5.8 s after receipt). We do not detect the counterpart seen by the Swift XRT (Racusin et al. GCN 5528) and P60 (Cenko et al. GCN 5529). The initial unfiltered 5 s exposure yields a 3-sigma limiting magnitude at the counterpart location of R=15.2 when calibrated against the GSC 1.1 R-band. This limit has not been corrected for foreground galactic extinction.
GCN Circular #5540
K. Torii (Osaka U.) reports:
The error region of GRB 060906 (Racusin et al. GCN 5528) was observed with the 0.3m telescope in the New Mexico Skies Observatory. Starting at 08:39:08 UT (6.4 minutes after the trigger), 120s x 20 frames were acquired through Ic filter.
At the position of the optical afterglow (Cenko et al. GCN 5529, 5531), we identify a marginal excess (at 3.2 sigma) that corresponds to I=17.7 (USNO-B1.0 magnitude) in a stacked frame (120s x first 10 frames). The analysis is preliminary.
GCN Circular #5542
F. Terra (Second University of Roma "Tor Vergata"), G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"), I. Bruni (Bologna Observatory), F. Strafella(University of Lecce and INFN, Lecce) and G. Pizzichini (INAF/IASF Bologna) report:
Using the 152 cm Loiano telescope equipped with the BFOSC camera system, in poor sky conditions (full moon, seeing = 1.8"), we obtained one Rc-band image (1 x 900 sec) of the field of GRB060906 (Racusin et al., GCN 5540), starting on September 6.962 . At a 3-sigma level the OT reported by Cenko et al. (GCN 5529) is not detected in our frame, which is slightly deeper than Rc=20.3. We used NOMAD1 as our reference catalog.
GCN Circular #5557
K. Wiersema (University of Amsterdam) and E. Rol (University of Leicester) report:
We observed the position of GRB060906 (Racusin et al. GCN5528) with the Danish 1.5m telescope at La Silla equipped with DFOSC. Observations were done under high airmass, starting on September 8 08:06 UT and ending at 08:52 UT. In the sum of 7 x 5 min exposures in I band we do not detect the optical afterglow (Cenko et al. GCN5529). Using a sample of 23 USNO-B stars we find a 3 sigma upper limit of I = 21.95. The standard deviation in the zeropoint as determined from the USNO stars is 0.24 mag.
astro-ph/0609450 from 15 Sep 2006
Jakobsson et al: HI column densities of z > 2 Swift gamma-ray bursts
Context: Before the launch of the Swift satellite, the majority of the gamma-ray burst (GRB) afterglows for which Ly-alpha was redshifted into the observable spectrum showed evidence for a damped Ly-alpha absorber. This small sample indicated that GRBs explode either in galaxies, or regions within them, having high neutral hydrogen column densities. Aims: To increase the spectroscopic sample of GRBs with z > 2 and hence establish the N(HI) distribution along GRB lines-of-sight. Methods: We have obtained six z > 2 GRB afterglow spectra and fitted the Ly-alpha absorption line in each case to determine N(HI). This has been complemented with 12 other Swift N(HI) values from the literature. Results: We show that the peak of the GRB N(HI) distribution is qualitatively consistent with a model where GRBs originate in Galactic-like molecular clouds. However, a systematic difference, in particular an excess of low column-density systems compared to the predictions, indicates that selection effects and conditions within the cloud (e.g. strong ionization) influence the observed N(HI) range. We also report the discovery of Ly-alpha emission from the GRB 060714 host, corresponding to a star-formation rate of approximately 0.8 M_Sun/year. Finally, we present accurate redshifts of the six bursts: z = 3.240 +/- 0.001 (GRB 050319), z = 2.198 +/- 0.002 (GRB 050922C), z = 3.221 +/- 0.001 (GRB 060526), z = 3.425 +/- 0.002 (GRB 060707), z = 2.711 +/- 0.001 (GRB 060714) and z = 3.686 +/- 0.002 (GRB 060906).

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Jochen Greiner, last update: 18-Oct-2006 [Disclaimer]