Gamma-ray Burst 060428

(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:     Fri 28 Apr 06 03:23:02 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     207364,   Seg_Num: 0
GRB_RA:          123.568d {+08h 14m 16s} (J2000),
                 123.626d {+08h 14m 30s} (current),
                 123.103d {+08h 12m 25s} (1950)
GRB_DEC:         -37.165d {-37d 09' 52"} (J2000),
                 -37.184d {-37d 11' 02"} (current),
                 -37.012d {-37d 00' 41"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4861 [cnts]    Image_Peak=189 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   138     E_range: 15-50 keV
BKG_INTEN:       33360 [cnts]
BKG_TIME:        12150.84 SOD {03:22:30.84} UT
BKG_DUR:         8 [sec]
GRB_DATE:        13853 TJD;   118 DOY;   06/04/28
GRB_TIME:        12168.05 SOD {03:22:48.05} UT
GRB_PHI:         137.90 [deg]
GRB_THETA:        25.41 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.43 [sigma]
IMAGE_SIGNIF:    7.35 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +1 +11  +0  +1 +12  +1 
SUN_POSTN:        35.35d {+02h 21m 25s}  +14.08d {+14d 04' 58"}
SUN_DIST:         97.11 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.63d {+02h 34m 31s}  +18.56d {+18d 33' 48"}
MOON_DIST:        97.27 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.72, -1.41 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      140.06,-54.92 [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 = 178.89,-18.75 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:24:36 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     207364,   Seg_Num: 0
GRB_RA:          123.5458d {+08h 14m 10.9s} (J2000),
                 123.6045d {+08h 14m 25.0s} (current),
                 123.0812d {+08h 12m 19.4s} (1950)
GRB_DEC:         -37.1692d {-37d 10' 09.1"} (J2000),
                 -37.1887d {-37d 11' 19.1"} (current),
                 -37.0163d {-37d 00' 58.6"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       117 [cnts]
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  12236.64 SOD {03:23:56.64} UT,   68.6 [sec] since BAT Trigger Time
CENTROID_X:      303.13,  raw= 303  [pixels]
CENTROID_Y:      319.42,  raw= 319  [pixels]
ROLL:            282.34 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   48.61
GRB_POS_XRT_Z:   4.31
IMAGE_URL:       sw00207364000msxps_rw.img
SUN_POSTN:        35.36d {+02h 21m 25s}  +14.08d {+14d 04' 59"}
SUN_DIST:         97.09 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.64d {+02h 34m 34s}  +18.57d {+18d 34' 09"}
MOON_DIST:        97.25 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.71, -1.43 [deg] galactic lon,lat of the burst
ECL_COORDS:      140.04,-54.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:24:52 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     207364,   Seg_Num: 0
GRB_RA:          123.5458d {+08h 14m 10.9s} (J2000),
                 123.6045d {+08h 14m 25.0s} (current),
                 123.0812d {+08h 12m 19.4s} (1950)
GRB_DEC:         -37.1692d {-37d 10' 09.1"} (J2000),
                 -37.1887d {-37d 11' 19.1"} (current),
                 -37.0163d {-37d 00' 58.6"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       117 [cnts]
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  12236.64 SOD {03:23:56.64} UT,   68.6 [sec] since BAT Trigger Time
CENTROID_X:      303.13,  raw= 303  [pixels]
CENTROID_Y:      319.42,  raw= 319  [pixels]
ROLL:            282.34 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   48.61
GRB_POS_XRT_Z:   4.31
IMAGE_URL:       sw00207364000msxps_rw.img
SUN_POSTN:        35.36d {+02h 21m 25s}  +14.08d {+14d 04' 59"}
SUN_DIST:         97.09 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.65d {+02h 34m 35s}  +18.57d {+18d 34' 12"}
MOON_DIST:        97.25 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.71, -1.43 [deg] galactic lon,lat of the burst
ECL_COORDS:      140.04,-54.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:24:34 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     207364,   Seg_Num: 0
GRB_RA:          123.5458d {+08h 14m 10.9s} (J2000),
                 123.6045d {+08h 14m 25.0s} (current),
                 123.0812d {+08h 12m 19.4s} (1950)
GRB_DEC:         -37.1692d {-37d 10' 09.1"} (J2000),
                 -37.1887d {-37d 11' 19.1"} (current),
                 -37.0163d {-37d 00' 58.6"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       3.21e-09 [erg/cm2/sec]
GRB_SIGNIF:      10.81 [sigma]
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  12236.64 SOD {03:23:56.64} UT,   68.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.60 237.16 261.18 243.15
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        35.36d {+02h 21m 25s}  +14.08d {+14d 04' 59"}
SUN_DIST:         97.09 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.64d {+02h 34m 34s}  +18.57d {+18d 34' 08"}
MOON_DIST:        97.25 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.71, -1.43 [deg] galactic lon,lat of the burst
ECL_COORDS:      140.04,-54.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:27:07 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     207364,   Seg_Num: 0
GRB_RA:          123.568d {+08h 14m 16s} (J2000),
                 123.626d {+08h 14m 30s} (current),
                 123.103d {+08h 12m 25s} (1950)
GRB_DEC:         -37.165d {-37d 09' 52"} (J2000),
                 -37.184d {-37d 11' 02"} (current),
                 -37.012d {-37d 00' 41"} (1950)
GRB_DATE:        13853 TJD;   118 DOY;   06/04/28
GRB_TIME:        12168.05 SOD {03:22:48.05} UT
TRIGGER_INDEX:   138
GRB_PHI:         137.90 [deg]
GRB_THETA:        25.41 [deg]
DELTA_TIME:      38.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     9.43 [sigma]
IMAGE_SIGNIF:    7.35 [sigma]
LC_URL:          sw00207364000msb.lc
SUN_POSTN:        35.36d {+02h 21m 26s}  +14.08d {+14d 05' 01"}
SUN_DIST:         97.11 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.67d {+02h 34m 40s}  +18.58d {+18d 34' 43"}
MOON_DIST:        97.25 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.72, -1.41 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      140.06,-54.92 [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 = 178.89,-18.75 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:33:30 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.548d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.156d {-37d 09' 20"} (J2000)
POINT_ROLL:      282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  12238.18 SOD {03:23:58.18} UT,   70.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.841
N_STARS:         190
X_OFFSET:        409 [pixels]
Y_OFFSET:        465 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1424 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00207364000msufc0070.fits
SUN_POSTN:        35.36d {+02h 21m 27s}  +14.09d {+14d 05' 06"}
SUN_DIST:         97.09 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.73d {+02h 34m 55s}  +18.60d {+18d 36' 09"}
MOON_DIST:        97.20 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:35:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.548d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.156d {-37d 09' 20"} (J2000)
POINT_ROLL:      282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  12238.18 SOD {03:23:58.18} UT,   70.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.841
N_STARS:         190
X_OFFSET:        409 [pixels]
Y_OFFSET:        465 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1424 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00207364000msufc0070.fits
SUN_POSTN:        35.36d {+02h 21m 27s}  +14.09d {+14d 05' 08"}
SUN_DIST:         97.09 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.75d {+02h 35m 00s}  +18.61d {+18d 36' 38"}
MOON_DIST:        97.19 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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:     Fri 28 Apr 06 03:35:54 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.548d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.156d {-37d 09' 20"} (J2000)
ROLL:            282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  12238.18 SOD {03:23:58.18} UT,   70.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     167887439
X_OFFSET:        729 [pixels]
Y_OFFSET:        785 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       945
BINNING_INDEX:   1
IM_URL:          sw00207364000msuni0070.fits
SUN_POSTN:        35.36d {+02h 21m 27s}  +14.09d {+14d 05' 08"}
SUN_DIST:         97.09 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.75d {+02h 35m 01s}  +18.61d {+18d 36' 41"}
MOON_DIST:        97.19 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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:     Fri 28 Apr 06 03:37:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.548d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.156d {-37d 09' 20"} (J2000)
ROLL:            282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  12238.18 SOD {03:23:58.18} UT,   70.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     167887439
X_OFFSET:        729 [pixels]
Y_OFFSET:        785 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       945
BINNING_INDEX:   1
IM_URL:          sw00207364000msuni0070.fits
SUN_POSTN:        35.36d {+02h 21m 28s}  +14.09d {+14d 05' 10"}
SUN_DIST:         97.09 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.77d {+02h 35m 05s}  +18.62d {+18d 37' 09"}
MOON_DIST:        97.18 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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:     Fri 28 Apr 06 03:44:12 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 13"} (J2000)
POINT_ROLL:      282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13025.18 SOD {03:37:05.18} UT,   857.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.789
N_STARS:         190
X_OFFSET:        409 [pixels]
Y_OFFSET:        465 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1424 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00207364000msufc0857.fits
SUN_POSTN:        35.37d {+02h 21m 29s}  +14.09d {+14d 05' 15"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.83d {+02h 35m 20s}  +18.64d {+18d 38' 33"}
MOON_DIST:        97.14 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:46:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 13"} (J2000)
POINT_ROLL:      282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13025.18 SOD {03:37:05.18} UT,   857.1 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.789
N_STARS:         190
X_OFFSET:        409 [pixels]
Y_OFFSET:        465 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1424 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00207364000msufc0857.fits
SUN_POSTN:        35.37d {+02h 21m 29s}  +14.09d {+14d 05' 16"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.85d {+02h 35m 25s}  +18.65d {+18d 39' 01"}
MOON_DIST:        97.13 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN Circular #5014
V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. R. Cummings (NASA/ORAU), N. Gehrels (NASA/GSFC), S. T. Holland (GSFC/USRA), J. A. Kennea (PSU), C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 03:22:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060428 (trigger=207364). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 123.568, -37.165 {08h 14m 16s, -37d 09' 52"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a main peak starting at ~T-5 sec and ending at ~T+15 sec. There is a possible second peak going from T+20 to T+40 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~4 sec after the trigger.
The XRT began observing the field at 03:23:56 UT, 69 seconds after the BAT trigger. XRT found a fading, uncatalogued X-ray source located at RA(J2000) = 08h 14m 10.9s, Dec(J2000) = -37d 10' 09.1", with an estimated uncertainty of 4.7 arcseconds (90% confidence radius). This location is 65 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 3.2e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 400 seconds with the V filter starting 71 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 3-sigma upper limit is about 19.1 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The limiting magnitude is expected to be about 17.5. No correction has been made for the large, but uncertain extinction expected.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:46:34 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 13"} (J2000)
ROLL:            282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13025.18 SOD {03:37:05.18} UT,   857.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     167888226
X_OFFSET:        729 [pixels]
Y_OFFSET:        785 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       945
BINNING_INDEX:   1
IM_URL:          sw00207364000msuni0857.fits
SUN_POSTN:        35.37d {+02h 21m 29s}  +14.09d {+14d 05' 17"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.86d {+02h 35m 26s}  +18.65d {+18d 39' 05"}
MOON_DIST:        97.13 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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:     Fri 28 Apr 06 03:48:31 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 13"} (J2000)
ROLL:            282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13025.18 SOD {03:37:05.18} UT,   857.1 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     167888226
X_OFFSET:        729 [pixels]
Y_OFFSET:        785 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       945
BINNING_INDEX:   1
IM_URL:          sw00207364000msuni0857.fits
SUN_POSTN:        35.37d {+02h 21m 29s}  +14.09d {+14d 05' 18"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.88d {+02h 35m 30s}  +18.66d {+18d 39' 31"}
MOON_DIST:        97.12 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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:     Fri 28 Apr 06 03:50:56 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 12"} (J2000)
POINT_ROLL:      282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13428.86 SOD {03:43:48.86} UT,   1260.8 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.803
N_STARS:         190
X_OFFSET:        409 [pixels]
Y_OFFSET:        465 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1424 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00207364000msufc1260.fits
SUN_POSTN:        35.37d {+02h 21m 30s}  +14.09d {+14d 05' 20"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.90d {+02h 35m 36s}  +18.67d {+18d 40' 03"}
MOON_DIST:        97.11 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 28 Apr 06 03:53:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 12"} (J2000)
POINT_ROLL:      282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13428.86 SOD {03:43:48.86} UT,   1260.8 [sec] since BAT Trigger Time
FILTER:          3, V
BKG_MEAN:        1.803
N_STARS:         190
X_OFFSET:        409 [pixels]
Y_OFFSET:        465 [pixels]
X_MAX:           1368 [pixels]
Y_MAX:           1424 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00207364000msufc1260.fits
SUN_POSTN:        35.37d {+02h 21m 30s}  +14.09d {+14d 05' 22"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.92d {+02h 35m 41s}  +18.68d {+18d 40' 36"}
MOON_DIST:        97.10 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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:     Fri 28 Apr 06 03:53:39 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 12"} (J2000)
ROLL:            282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13428.86 SOD {03:43:48.86} UT,   1260.8 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     167888630
X_OFFSET:        729 [pixels]
Y_OFFSET:        785 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       945
BINNING_INDEX:   1
IM_URL:          sw00207364000msuni1260.fits
SUN_POSTN:        35.38d {+02h 21m 30s}  +14.09d {+14d 05' 22"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.93d {+02h 35m 42s}  +18.68d {+18d 40' 40"}
MOON_DIST:        97.10 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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:     Fri 28 Apr 06 03:55:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     207364,   Seg_Num: 0
POINT_RA:        123.547d {+08h 14m 11s} (J2000)
POINT_DEC:       -37.154d {-37d 09' 12"} (J2000)
ROLL:            282.336d
IMG_START_DATE:  13853 TJD;   118 DOY;   06/04/28
IMG_START_TIME:  13428.86 SOD {03:43:48.86} UT,   1260.8 [sec] since BAT Trigger Time
FILTER:          3, V
EXPOSURE_ID:     167888630
X_OFFSET:        729 [pixels]
Y_OFFSET:        785 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       889
Y_GRB_POS:       945
BINNING_INDEX:   1
IM_URL:          sw00207364000msuni1260.fits
SUN_POSTN:        35.38d {+02h 21m 30s}  +14.09d {+14d 05' 24"}
SUN_DIST:         97.08 [deg]   Sun_angle= -5.9 [hr] (East of Sun)
MOON_POSTN:       38.95d {+02h 35m 47s}  +18.69d {+18d 41' 08"}
MOON_DIST:        97.08 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      254.70, -1.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      140.03,-54.92 [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 #5018
V. Mangano (INAF-IASFPA), E. Troja (INAF-IASFPA), D. N. Burrows (PSU) report on behalf of the Swift XRT Team:
We have analyzed the first orbit data of GRB060428A (Mangano et al 2006, GCN 5014). The XRT data set consists of 39 s exposure in Windowed Timing (WT) mode followed by 1670 s exposure in Photon Counting (PC) mode.
The refined position of the source is
```
    RA  (2000) =  08h 14m 10.98s 
    Dec (2000) = -37d 10' 10.3"
```
with an uncertainty of 3.6 arcsec (90% confinement). This position is only 1.5 arcsec from the onboard detected position (Mangano et al 2006, GCN 5014).
The 0.2-10 keV X-ray light curve shows an initial very fast decay with slope -6.3 +/- 0.4, a break at 144 +/- 6 s from the trigger and a flattening with a decay slope of -0.11 +/- 0.03. A small flare with a gaussian profile is present at 676 +/- 56 s after the trigger.
The WT and PC spectra were fitted separately with an absorbed power law model and showed photon indices of 3.2 +/- 0.4 and 1.9 +/- 0.2, respectively (90% confidence level). The WT spectrum, covering the time interval 77-116 s, mostly accounts for the pre-break phase of the light curve.
Both spectra are highly absorbed, but do not show evidence of an absorption column in excess with respect to the Galactic value of 8.5 x 10^21 cm^-2. The 0.2-10 keV unabsorbed fluxes of the two spectra are 2.9 x 10^-9 and 7.6 x 10^-11 erg cm^-2 s^-1, respectively.
If decaying at the present rate the source will be at the flux level of 2.7 x 10^-11 erg cm^-2 s^-1 (corresponding to a count rate level of 0.18 counts s^-1) after one day.
This Circular is an official product of the Swift XRT Team.
GCN Circular #5022
C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), V. Mangano (INAF-IASFPA), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 060428A (trigger #207364) (Mangano, et al., GCN 5014). The BAT ground-calculated position is RA,Dec = 123.535,-37.169 deg {8h 14m 8.5s, -37d 10' 8.6"} (J2000) +- 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 65%.
The mask-weighted lightcurve shows a bright peak (starting at T-8 sec until T+20 sec with the peak at T+5 sec) and a weaker peak (T+22 sec until T+42 sec). T90 (15-350 keV) is 39.4 +- 2 sec (estimated error including systematics).
The time-averaged spectrum from T-6.8 to T+43.0 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.04 +- 0.11. The fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+4.41 sec in the 15-150 keV band is 2.4 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
GCN Circular #5024
M. De Pasquale (UCL-MSSL), V. Mangano (IASF Palermo) report on behalf of the Swift/UVOT team:
The Swift/UVOT began taking data on the field of GRB060428A at 03:23:48 UT on 2006-04-28, 60 s after the BAT trigger (Mangano et al., GCN 5014), with the settling exposure. In the refined XRT error circle (Magano et al., GCN 5018), we find a weak (4 sigma detection) optical source in the V band at about V=20, not present in USNO B1.0 catalogue. This source however appears to be constant throughout the observation, thus further observations will be needed to determine if it is the optical afterglow of this burst.
No other afterglow candidate was detected at the refined XRT position in summed images from any of the filters down to the following three-sigma upper limits.
```
   Filter  T_range(s)  Exp(s) 3sig_UL

   V        60-7526    1657   20.2
   B       548-7116    442    20.5
   U       524-13380   436    20.5
   UVW1    500-12666   1358   20.0
   UVM2    476-11758   1425   19.9
   UVW2    563-7322    472    19.5
```
These upper limits are uncorrected for the strong estimated Galactic reddening of E_{B-V} = 1.25 mag (Schlegel et al. 1998).
GCN Circular #5033
J. Haislip, M. Nysewander, A. Foster, A. LaCluyze, D. Reichart, J. A. Crain, K. Ivarsen, J. Kirschbrown, C. MacLeod, A. Trotter, and J. Carpenter report on behalf of the UNC team of the FUN GRB Collaboration:
Skynet observed the localization of GRB 060428A (Mangano et al., GCN 5014) with three of the 16-inch PROMPT telescopes at CTIO beginning 58 sec after the burst (44 sec after notification) in Ug'r'i'z' (three simultaneously).
No new source is found to z' > 17.1 mag (3 sigma; 10 sec exposure) at 63 sec after the burst and z' > 19.1 (3 sigma; 4 x 40 sec exposures) at 5.3 min after the burst.
PROMPT is currently being built and commissioned.
GCN Circular #5111
B. E. Cobb (Yale), part of the larger SMARTS consortium, reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 060428a (GCN 5014, Mangano et al.) with a mid-exposure time of 2006-04-29 00:17 UT, which is ~20.9 hours post-burst and again at 2006-04-30 23:46 UT (~68.4 hours post-burst). For each observation total summed exposure times amounted to 36 minutes in I and 30 minutes in J.
In our first epoch images, a source is visible in both I and J within the X-ray error region reported by Mangano et al. (GCN 5018). This source may correspond to the V-band source detected by De Pasquale & Mangano (GCN 5024) in the Swift UVOT imaging. The coordinates are:
```
RA: 8:14:10.8
DEC: -37:10:11.4
```
The source is absent in our second epoch images. Its transient nature (see magnitudes below) suggests that the source is the afterglow of GRB 060428a.
```
time
post-burst      I magnitude             J magnitude
------------------------------------------------------
20.9 hours      21.14 +/- 0.16          18.98 +/- 0.14
68.4 hours      >22.2+/-0.2             >19.6+/-0.2
```
These preliminary magnitudes were calibrated using several USNO-B1.0 stars in the I-band and several 2MASS standards in J.
The afterglow decay index is constrained by our observations to be alpha >~ -0.8 from ~1 to 3 days post-burst. Because no optical source was detected with magnitude <20 at only minutes post-burst (see GCN 5033, Haislip et al. [z'>19.1 at 5.3 minutes] and GCN 5024, De Pasquale & Mangano [V=20 at 1 minute]), our I-band detection at 20.9 hours suggests that the early time decay rate of the afterglow must have been significantly more shallow than -0.8. This may partially account for the lack of detected variability of the UVOT source at early times. Possibly, a light curve break occurred between our two sets of observations.

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Jochen Greiner, last update: 11-May-2006 [Disclaimer]