Gamma-ray Burst 061004

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:50:44 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     232339,   Seg_Num: 0
GRB_RA:           97.748d {+06h 30m 60s} (J2000),
                  97.796d {+06h 31m 11s} (current),
                  97.392d {+06h 29m 34s} (1950)
GRB_DEC:         -45.894d {-45d 53' 36"} (J2000),
                 -45.899d {-45d 53' 55"} (current),
                 -45.857d {-45d 51' 24"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5100 [cnts]    Image_Peak=231 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   137     E_range: 25-100 keV
BKG_INTEN:       32756 [cnts]
BKG_TIME:        71414.51 SOD {19:50:14.51} UT
BKG_DUR:         8 [sec]
GRB_DATE:        14012 TJD;   277 DOY;   06/10/04
GRB_TIME:        71430.51 SOD {19:50:30.51} UT
GRB_PHI:         173.68 [deg]
GRB_THETA:        16.57 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.19 [sigma]
IMAGE_SIGNIF:    8.20 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2 +14  +0  +0  -2  +1 
SUN_POSTN:       190.52d {+12h 42m 06s}   -4.53d {-04d 31' 35"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.95d {+22h 43m 47s}   -9.55d {-09d 32' 49"}
MOON_DIST:       101.00 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.31,-22.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      105.13,-68.93 [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 = 118.52,-18.75 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:52:02 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     232339,   Seg_Num: 0
GRB_RA:           97.7947d {+06h 31m 10.7s} (J2000),
                  97.8428d {+06h 31m 22.2s} (current),
                  97.4388d {+06h 29m 45.3s} (1950)
GRB_DEC:         -45.9064d {-45d 54' 23.0"} (J2000),
                 -45.9115d {-45d 54' 41.4"} (current),
                 -45.8695d {-45d 52' 10.1"} (1950)
GRB_ERROR:       6.5 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       26 [cnts]
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71490.73 SOD {19:51:30.73} UT,   60.2 [sec] since BAT Trigger Time
CENTROID_X:      264.60,  raw= 265  [pixels]
CENTROID_Y:      280.72,  raw= 281  [pixels]
ROLL:            95.11 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -42.60
GRB_POS_XRT_Z:   -86.49
IMAGE_URL:       sw00232339000msxps_rw.img
SUN_POSTN:       190.52d {+12h 42m 06s}   -4.53d {-04d 31' 37"}
SUN_DIST:         88.61 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.96d {+22h 43m 50s}   -9.54d {-09d 32' 27"}
MOON_DIST:       101.02 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.34,-22.47 [deg] galactic lon,lat of the burst
ECL_COORDS:      105.22,-68.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:51:57 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     232339,   Seg_Num: 0
GRB_RA:           97.7947d {+06h 31m 10.7s} (J2000),
                  97.8428d {+06h 31m 22.2s} (current),
                  97.4388d {+06h 29m 45.3s} (1950)
GRB_DEC:         -45.9064d {-45d 54' 23.0"} (J2000),
                 -45.9115d {-45d 54' 41.4"} (current),
                 -45.8695d {-45d 52' 10.1"} (1950)
GRB_ERROR:       6.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       4.65e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.09 [sigma]
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71490.73 SOD {19:51:30.73} UT,   60.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.60 237.16 261.14 243.45
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       190.52d {+12h 42m 06s}   -4.53d {-04d 31' 36"}
SUN_DIST:         88.61 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.96d {+22h 43m 50s}   -9.54d {-09d 32' 28"}
MOON_DIST:       101.02 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.34,-22.47 [deg] galactic lon,lat of the burst
ECL_COORDS:      105.22,-68.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:51:58 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     232339,   Seg_Num: 0
GRB_RA:           97.7947d {+06h 31m 10.7s} (J2000),
                  97.8428d {+06h 31m 22.2s} (current),
                  97.4388d {+06h 29m 45.3s} (1950)
GRB_DEC:         -45.9064d {-45d 54' 23.0"} (J2000),
                 -45.9115d {-45d 54' 41.4"} (current),
                 -45.8695d {-45d 52' 10.1"} (1950)
GRB_ERROR:       6.5 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       26 [cnts]
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71490.73 SOD {19:51:30.73} UT,   60.2 [sec] since BAT Trigger Time
CENTROID_X:      264.60,  raw= 265  [pixels]
CENTROID_Y:      280.72,  raw= 281  [pixels]
ROLL:            95.11 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -42.60
GRB_POS_XRT_Z:   -86.49
IMAGE_URL:       sw00232339000msxps_rw.img
SUN_POSTN:       190.52d {+12h 42m 06s}   -4.53d {-04d 31' 36"}
SUN_DIST:         88.61 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.96d {+22h 43m 50s}   -9.54d {-09d 32' 28"}
MOON_DIST:       101.02 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.34,-22.47 [deg] galactic lon,lat of the burst
ECL_COORDS:      105.22,-68.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:53:40 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.892d {-45d 53' 30"} (J2000)
POINT_ROLL:      95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71499.05 SOD {19:51:39.05} UT,   68.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.412
N_STARS:         190
X_OFFSET:        416 [pixels]
Y_OFFSET:        584 [pixels]
X_MAX:           1375 [pixels]
Y_MAX:           1543 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00232339000msufc0068.fits
SUN_POSTN:       190.53d {+12h 42m 06s}   -4.53d {-04d 31' 38"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.97d {+22h 43m 54s}   -9.53d {-09d 32' 00"}
MOON_DIST:       101.01 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:54:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.892d {-45d 53' 30"} (J2000)
POINT_ROLL:      95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71499.05 SOD {19:51:39.05} UT,   68.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.412
N_STARS:         190
X_OFFSET:        416 [pixels]
Y_OFFSET:        584 [pixels]
X_MAX:           1375 [pixels]
Y_MAX:           1543 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00232339000msufc0068.fits
SUN_POSTN:       190.53d {+12h 42m 06s}   -4.53d {-04d 31' 39"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.98d {+22h 43m 55s}   -9.53d {-09d 31' 51"}
MOON_DIST:       101.00 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.92 [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:     Wed 04 Oct 06 19:54:54 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.892d {-45d 53' 30"} (J2000)
ROLL:            95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71499.05 SOD {19:51:39.05} UT,   68.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     181684300
X_OFFSET:        980 [pixels]
Y_OFFSET:        854 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1140
Y_GRB_POS:       1014
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0068.fits
SUN_POSTN:       190.53d {+12h 42m 06s}   -4.53d {-04d 31' 39"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.99d {+22h 43m 56s}   -9.53d {-09d 31' 38"}
MOON_DIST:       101.00 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:55:09 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     232339,   Seg_Num: 0
GRB_RA:           97.748d {+06h 30m 60s} (J2000),
                  97.796d {+06h 31m 11s} (current),
                  97.392d {+06h 29m 34s} (1950)
GRB_DEC:         -45.894d {-45d 53' 36"} (J2000),
                 -45.899d {-45d 53' 55"} (current),
                 -45.857d {-45d 51' 24"} (1950)
GRB_DATE:        14012 TJD;   277 DOY;   06/10/04
GRB_TIME:        71430.51 SOD {19:50:30.51} UT
TRIGGER_INDEX:   137
GRB_PHI:         173.68 [deg]
GRB_THETA:        16.57 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.19 [sigma]
IMAGE_SIGNIF:    8.20 [sigma]
LC_URL:          sw00232339000msb.lc
SUN_POSTN:       190.53d {+12h 42m 06s}   -4.53d {-04d 31' 40"}
SUN_DIST:         88.65 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.99d {+22h 43m 57s}   -9.53d {-09d 31' 34"}
MOON_DIST:       100.99 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.31,-22.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      105.13,-68.93 [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 = 118.52,-18.75 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 19:55:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.892d {-45d 53' 30"} (J2000)
ROLL:            95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71499.05 SOD {19:51:39.05} UT,   68.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     181684300
X_OFFSET:        980 [pixels]
Y_OFFSET:        854 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1140
Y_GRB_POS:       1014
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0068.fits
SUN_POSTN:       190.53d {+12h 42m 06s}   -4.53d {-04d 31' 40"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      340.99d {+22h 43m 57s}   -9.53d {-09d 31' 33"}
MOON_DIST:       101.00 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:01:26 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
POINT_ROLL:      95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71604.39 SOD {19:53:24.39} UT,   173.9 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.308
N_STARS:         190
X_OFFSET:        660 [pixels]
Y_OFFSET:        534 [pixels]
X_MAX:           1619 [pixels]
Y_MAX:           1493 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00232339000msufc0173.fits
SUN_POSTN:       190.53d {+12h 42m 07s}   -4.53d {-04d 31' 46"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.05d {+22h 44m 11s}   -9.50d {-09d 29' 47"}
MOON_DIST:       100.99 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:01:51 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
POINT_ROLL:      95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71604.39 SOD {19:53:24.39} UT,   173.9 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.308
N_STARS:         190
X_OFFSET:        660 [pixels]
Y_OFFSET:        534 [pixels]
X_MAX:           1619 [pixels]
Y_MAX:           1493 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00232339000msufc0173.fits
SUN_POSTN:       190.53d {+12h 42m 07s}   -4.53d {-04d 31' 46"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.05d {+22h 44m 12s}   -9.49d {-09d 29' 40"}
MOON_DIST:       100.99 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [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:     Wed 04 Oct 06 20:02:40 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
ROLL:            95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71604.39 SOD {19:53:24.39} UT,   173.9 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     181684405
X_OFFSET:        980 [pixels]
Y_OFFSET:        854 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1140
Y_GRB_POS:       1014
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0173.fits
SUN_POSTN:       190.53d {+12h 42m 08s}   -4.53d {-04d 31' 47"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.06d {+22h 44m 14s}   -9.49d {-09d 29' 26"}
MOON_DIST:       100.99 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:02:56 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
ROLL:            95.108d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  71604.39 SOD {19:53:24.39} UT,   173.9 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     181684405
X_OFFSET:        980 [pixels]
Y_OFFSET:        854 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1140
Y_GRB_POS:       1014
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0173.fits
SUN_POSTN:       190.53d {+12h 42m 08s}   -4.53d {-04d 31' 47"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.06d {+22h 44m 15s}   -9.49d {-09d 29' 22"}
MOON_DIST:       100.98 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:07:09 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
POINT_ROLL:      95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72308.43 SOD {20:05:08.43} UT,   877.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.106
N_STARS:         190
X_OFFSET:        660 [pixels]
Y_OFFSET:        534 [pixels]
X_MAX:           1619 [pixels]
Y_MAX:           1493 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00232339000msufc0877.fits
SUN_POSTN:       190.53d {+12h 42m 08s}   -4.53d {-04d 31' 51"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.10d {+22h 44m 24s}   -9.47d {-09d 28' 10"}
MOON_DIST:       100.98 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:07:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
POINT_ROLL:      95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72308.43 SOD {20:05:08.43} UT,   877.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.106
N_STARS:         190
X_OFFSET:        660 [pixels]
Y_OFFSET:        534 [pixels]
X_MAX:           1619 [pixels]
Y_MAX:           1493 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00232339000msufc0877.fits
SUN_POSTN:       190.53d {+12h 42m 08s}   -4.53d {-04d 31' 51"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.10d {+22h 44m 25s}   -9.47d {-09d 28' 04"}
MOON_DIST:       100.97 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [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:     Wed 04 Oct 06 20:10:32 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
ROLL:            95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72308.43 SOD {20:05:08.43} UT,   877.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     181685109
X_OFFSET:        979 [pixels]
Y_OFFSET:        853 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1139
Y_GRB_POS:       1013
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0877.fits
SUN_POSTN:       190.54d {+12h 42m 09s}   -4.53d {-04d 31' 54"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.13d {+22h 44m 32s}   -9.45d {-09d 27' 12"}
MOON_DIST:       100.97 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [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).  
COMMENTS:        This notice was forced out after watchdog timer expiring -- most likely due to missing packet(s);  
COMMENTS:        as a consequence some of the fields may be incoorect (eg TRIGGER_NUM,RA,DEC).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:10:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
ROLL:            95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72308.43 SOD {20:05:08.43} UT,   877.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     181685109
X_OFFSET:        979 [pixels]
Y_OFFSET:        853 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1139
Y_GRB_POS:       1013
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0877.fits
SUN_POSTN:       190.54d {+12h 42m 09s}   -4.53d {-04d 31' 55"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.13d {+22h 44m 32s}   -9.45d {-09d 27' 08"}
MOON_DIST:       100.97 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [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.  
COMMENTS:        This notice was forced out after watchdog timer expiring -- most likely due to missing packet(s);  
COMMENTS:        as a consequence some of the fields may be incoorect (eg TRIGGER_NUM,RA,DEC).

GCN Circular #5691
H. Ziaeepour (UCL-MSSL), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), S. R. Oates (UCL-MSSL), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), G. Sato (GSFC/ISAS), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 19:50:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 061004 (trigger=232339). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 97.748, -45.894 {06h 30m 60s, -45d 53' 36"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a peak with a duration of about 6 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 19:51:30 UT, 60 seconds after the BAT trigger. XRT found a bright, variable, uncatalogued X-ray source located at RA(J2000) = 06h 31m 10.52s, Dec(J2000) = -45d 54' 24.0", with an estimated uncertainty of 6 arcseconds (90% confidence radius). This location is 124 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 4.6e-10 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 69 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 18.0 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.049

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:24:25 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
POINT_ROLL:      95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72413.68 SOD {20:06:53.68} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        2.289
N_STARS:         190
X_OFFSET:        660 [pixels]
Y_OFFSET:        534 [pixels]
X_MAX:           1619 [pixels]
Y_MAX:           1493 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00232339000msufc0983.fits
SUN_POSTN:       190.55d {+12h 42m 11s}   -4.54d {-04d 32' 08"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.26d {+22h 45m 03s}   -9.39d {-09d 23' 16"}
MOON_DIST:       100.94 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 04 Oct 06 20:24:54 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
POINT_ROLL:      95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72413.68 SOD {20:06:53.68} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        2.289
N_STARS:         190
X_OFFSET:        660 [pixels]
Y_OFFSET:        534 [pixels]
X_MAX:           1619 [pixels]
Y_MAX:           1493 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00232339000msufc0983.fits
SUN_POSTN:       190.55d {+12h 42m 11s}   -4.54d {-04d 32' 08"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.27d {+22h 45m 04s}   -9.39d {-09d 23' 08"}
MOON_DIST:       100.94 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [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:     Wed 04 Oct 06 20:25:51 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
ROLL:            95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72413.68 SOD {20:06:53.68} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     181685215
X_OFFSET:        979 [pixels]
Y_OFFSET:        853 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1139
Y_GRB_POS:       1013
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0983.fits
SUN_POSTN:       190.55d {+12h 42m 11s}   -4.54d {-04d 32' 09"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.28d {+22h 45m 06s}   -9.38d {-09d 22' 52"}
MOON_DIST:       100.93 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [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 04 Oct 06 20:26:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     232339,   Seg_Num: 0
POINT_RA:         97.762d {+06h 31m 03s} (J2000)
POINT_DEC:       -45.895d {-45d 53' 40"} (J2000)
ROLL:            95.109d
IMG_START_DATE:  14012 TJD;   277 DOY;   06/10/04
IMG_START_TIME:  72413.68 SOD {20:06:53.68} UT,   983.2 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     181685215
X_OFFSET:        979 [pixels]
Y_OFFSET:        853 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1139
Y_GRB_POS:       1013
BINNING_INDEX:   1
IM_URL:          sw00232339000msuni0983.fits
SUN_POSTN:       190.55d {+12h 42m 11s}   -4.54d {-04d 32' 09"}
SUN_DIST:         88.64 [deg]   Sun_angle= 6.2 [hr] (West of Sun)
MOON_POSTN:      341.28d {+22h 45m 07s}   -9.38d {-09d 22' 46"}
MOON_DIST:       100.93 [deg]
MOON_ILLUM:      92 [%]
GAL_COORDS:      254.32,-22.49 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.15,-68.93 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #5693
D.B. Fox (Penn State) reports:
"I note the presence of a 2MASS galaxy, 2MASX J06310985-4554013, at 23 arcsec distance from the XRT position for GRB 061004 (Ziaeepour et al., GCN 5691). Estimated magnitudes of the host galaxy from the 2MASS catalog, via NED, are: J=15.17(24) mag, H=14.72(35) mag, and Ks=13.60(22) mag (uncertainties in the least significant digits are given in parentheses). The proximity of this galaxy to the X-ray afterglow may be interesting in light of the relatively short 6-s duration of GRB 061004."
GCN Circular #5694
H. Krimm (GSFC/USRA), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), 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-239.0 to T+595.8 sec from the recent telemetry downlink, we report further analysis of BAT GRB 061004 (trigger #232339) (Ziaeepour, et al., GCN Circ. 5691). The BAT ground-calculated position is RA,Dec = 97.795, -45.903 deg {6h 31m 10.8s, -45d 54' 9.8"} (J2000) +- 0.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%.
The light curve shows a single peak, extending out to T+8 seconds. T90 (15-350 keV) is 6.2 +- 0.3 sec (estimated error including systematics).
The time-averaged spectrum from T+0.2 to T+8.1 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.81 +- 0.10. The fluence in the 15-150 keV band is 5.7 +- 0.3 x 10-07 erg/cm2. The 1-sec peak photon flux measured from T+2.67 sec in the 15-150 keV band is 2.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #5695
K.L. Page, A.P. Beardmore (U. Leicester) & H. Ziaeepour (UCL-MSSL) report on behalf of the Swift-XRT Team:
We have analysed the first 2 orbits of Swift-XRT data obtained for GRB 061004 (GCN Circ. 5691; Ziaeepour et al.). Using 3.8 ks of Photon Counting mode data, we derive a refined position of:
```
RA(J2000) =   06 31 10.48
Dec(J2000) = -45 54 24.6
```
with an estimated error radius of 5.5 arcsec (90% confidence, including boresight uncertainties). This lies 0.7 arcsec from the original XRT position given in GCN Circ. 5691 and 14.2 arcsec from the ground-calculated BAT position in GCN Circ. 5694 (Krimm et al).
The X-ray light-curve shows an initial decay of alpha = 1.62 +/- 0.14, breaking around 375 seconds after the burst to a flatter decay slope of 0.61 +/- 0.10.
The WT spectrum can be modelled using a power-law of Gamma = 1.53 +/- 0.48, absorbed by the Galactic column of 5.7e20 cm^-2. There is no evidence for any excess NH. The mean observed (unabsorbed) flux over 0.3-10 keV for this spectrum (spanning a time of 68-86 seconds after the trigger) is 2.83e-10 (3.07e-10) erg cm^-2 s^-1.
If the decay continues with a slope of alpha ~ 0.61, the count rate at 24 hours after the burst is predicted to be 0.012 count s^-1. Using a conversion factor of 1 count s^-1 being approximately equivalent to 4.6e-11 erg cm^-2 s^-1 (observed flux), this corresponds to a flux of 2.8e-11 erg cm^-2 s^-1 (over 0.3-10 keV). The predicted unabsorbed flux at 24 hours is 3.2e-11 erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.

GCN Circular #5696
S. R. Oates (UCL-MSSL), H. Ziaeepour (UCL-MSSL) report on behalf of the Swift UVOT team
The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB061004 at 19:51:14 UT, ~51 seconds after the initial Swift BAT trigger (Ziaeepour et al, GCN 5691). No optical counterpart was detected at the XRT position (Page et al, 6595) within the coadded images or with the V and white finding charts.
The 3 sigma upper limits are provided for the coadded images and the finding charts below:

Filter           Start      Stop    Exposure  3SigmaUL
--------------------------------------------------------
WHITE (finding)    68        168        100     18.4
V (finding)       174        574        400     20.0

V                 704      24752       1477     18.9
B                 652      13187        928     19.9
U                 625      18969       1225     20.5
UVW1              604      18895       2121     21.2
UVM2              580      17988       1357     20.4
UVW2              680      24092       1337     20.5
WHITE             665       6706        520     20.3
--------------------------------------------------------

The values quoted above are not corrected for the expected Galactic extinction of E_{B-V}=0.049.

GCN Circular #5697
E. Berger (Carnegie), S. Gonzalez, and W. Krzeminski (LCO) report:
"We observed the XRT position (GCN 5695) of GRB 061004 (GCN 5694) using the du Pont 100-inch telescope in K-band and the Swope 40-inch telescope in r-band. A total of 1215 sec and 1200 sec were obtained in each filter, respectively, starting on 2006 Oct 5.313 and Oct 5.338 UT. We do not detect any sources within the XRT error circle to a 3-sigma limit of K=18.9 mag and r=22.0 mag."
GCN Circular #5698
Pall Jakobsson (U. Hertfordshire), Johan P. U. Fynbo, Brian L. Jensen , Jens Hjorth (DARK, NBI), Andrew Levan (U. Hertfordshire), Nial Tanvir (U. Leicester), Paul Vreeswijk and Cedric Ledoux (ESO) report on behalf of a larger collaboration:
Using FORS1 on the Very Large Telescope, we have imaged the GRB 061004 field (Ziaeepour et al. GCN 5691) on Oct 5.369 (0.542 days post-burst). Inside the revised XRT circle (Page et al. GCN 5695) we find an R ~ 23 mag point source, using photometric zeropoints from the ESO webpages. At present we cannot confirm that the source is fading. Its coordinates are:
```
R.A.(J2000) =  06:31:10.71
Dec(J2000)  = -45:54:28.7
```
with a 0.3" error in each coordinate.
We obtained a 30 min spectrum (300V grating) of this source immediately after imaging. The spectrum displays an absorption feature around 5230 A, with the flux dropping substantially blueward of this feature. Associating it with Ly-alpha gives a redshift of z ~ 3.3 for this proposed afterglow candidate.
A finding chart can be found at: http://www.dark-cosmology.dk/~brian_j/grb/grb061004.827/
We thank the Paranal staff, especially Chris Lidman and Rachel Gilmour for excellent support.
GCN Report 4.1
GCN_Report 4.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_4_1.pdf by H.Ziaeepour titled: "Swift Observations of GRB 061004"
GCN Circular #5774
J. L. Racusin (PSU), D. N. Burrows (PSU), K. L. Page (U Leicester), H. Ziaeepour (UCL-MSSL), and N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT team:
We have re-analyzed the full XRT data set of GRB 061004. XRT observed the field of GRB 061004 for a total exposure time of 61 ks between October 4 and October 10, 2006 in Photon Counting mode.
Applying the new XRT boresight definition (Burrows et al., GCN 5750), we find a boresight corrected position of RA(J2000): 06h 31m 10.68s, Dec(J2000): -45d 54' 22.7", with an estimated uncertainty of 3.6 arcseconds (radius, 90% containment).
To further improve the accuracy of this position, we performed an astrometry correction using 54 ks of the total exposure time (when the satellite position was stable). In this data set we find 26 serendipitous X-ray sources detected with the XIMAGE detect algorithm with S/N > 3, 5 of which have near-by optical counterparts in the USNO-B1 catalog. We match these sources to obtain a best fit mean frame shift, carefully accounting for several instrumental factors including exposure map correction, and additional hot pixel removal.
We calculate the statistical position errors using the empirical fits as described in Moretti et al. (2006, A&A, 448, L9), assuming that the astrometric correction removes the 3.5" systematic error normally applied to XRT positions to account for errors in the star tracker attitude solution.
The result of this analysis leads to a mean frame shift from the previously reported position (Page et al., GCN 5695), of:
RA offset: +0.49s +/- 0.07s Dec offset: +1.3" +/- 1.0"
and a new XRT astrometry corrected position of:
```
RA(J2000):   06h 31m 10.94s
Dec(J2000): -45d 54' 23.3"
```
with an estimated uncertainty of 2.0 arcseconds (radius, 90% containment).
This position is 5.0 arcseconds from the original refined XRT position given in Page et al. (GCN 5695), 2.8 arcseconds from the boresight corrected XRT position, and 5.9 arcseconds from the faint VLT optical object described in Jakobsson et al. (GCN 5698).
A figure comparing all of these positions is available at: http://www.swift.psu.edu/images/grb061004_astrometry.gif
This Circular is an official product of the Swift XRT team.
GCN Circular #5782
Pall Jakobsson (U. Hertfordshire), Johan P. U. Fynbo, Brian L. Jensen , Jens Hjorth, Maximilian D. Stritzinger (DARK, NBI), Andrew Levan (U. Hertfordshire), Nial Tanvir (U. Leicester), Paul Vreeswijk, Cedric Ledoux (ESO), Houri Ziaeepour (UCL-MSSL) and Mathew Smith (U. Portsmouth) report on behalf of a larger collaboration:
We have performed follow-up observations of the GRB 061004 optical afterglow candidate (S1) reported in Jakobsson et al. (GCN 5698). The S1 flux is roughly constant between the three epochs of observations:
```
Tel/inst   Date (UT)    Delta-t   Exp. time     Magnitude
                         (days)    (s)
--------------------------------------------------------------
VLT/FORS1  Oct  5.366    0.539    2*300         22.55 +/- 0.09
VLT/FORS1  Oct  7.344    2.517    2*300 + 120   22.82 +/- 0.07
NTT/EMMI   Oct 15.352   10.525    3*500         22.73 +/- 0.20
```
In addition, S1 is 3.9" from the edge of the revised XRT error circle (Racusin et al. GCN 5774). The most likely conclusion is that S1 is not associated with the GRB.
There is no evidence for other sources inside the revised XRT error circle. The limiting magnitude of our first epoch observation is R > 25.1 (2 sigma). The corresponding upper limit on beta_OX is 0.42, rendering the burst dark according to the definition proposed by Jakobsson et al. (2004, ApJ, 617, L21).
Considering the brightness of S1, it is unlikely that it is a normal galaxy if z ~ 3.3 (GCN 5698). The relatively low S/N of the VLT spectrum makes it difficult to reach a firm conclusion on the reality of absorption features (apart from the feature around 5230 A). The lack of broad emission lines and the marginal evidence for optical variability might indicate that S1 is a blazar. An alternative scenario is that S1 is at a lower redshift. The 5230 A feature could be the Balmer/4000 A break, indicating a redshift of z ~ 0.3.
We thank Kim Page for providing us with the afterglow X-ray flux.
GCN Report 4.2
GCN_Report 4.2 has been posted: http://gcn.gsfc.nasa.gov/reports/report_4_2.pdf by H.Ziaeepour at MSSL/UCL titled: "Updated Swift Observations of GRB 061004"

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Jochen Greiner, last update: 06-Nov-2006 [Disclaimer]