Gamma-ray Burst 110402A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:13:14 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     323395980
GRB_RA:          189.000d {+12h 36m 00s} (J2000),
                 189.123d {+12h 36m 30s} (current),
                 188.451d {+12h 33m 48s} (1950)
GRB_DEC:         +65.017d {+65d 00' 60"} (J2000),
                 +64.955d {+64d 57' 17"} (current),
                 +65.292d {+65d 17' 30"} (1950)
GRB_ERROR:       19.77 [deg radius, statistical plus systematic]
GRB_INTEN:       327 [cnts/sec]
DATA_SIGNIF:     6.60 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        15653 TJD;    92 DOY;   11/04/02
GRB_TIME:        778.54 SOD {00:12:58.54} UT
GRB_PHI:          72.00 [deg]
GRB_THETA:       135.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.81
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 0,1,0, 0,0,
SUN_POSTN:        10.96d {+00h 43m 50s}   +4.71d {+04d 42' 38"}
SUN_DIST:        110.32 [deg]   Sun_angle= -11.9 [hr] (East of Sun)
MOON_POSTN:      352.90d {+23h 31m 35s}   +2.35d {+02d 20' 50"}
MOON_DIST:       111.66 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      125.58, 52.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      144.28, 59.08 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 136.78,24.50 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:13:23 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     323395980
GRB_RA:          182.117d {+12h 08m 28s} (J2000),
                 182.257d {+12h 09m 02s} (current),
                 181.488d {+12h 05m 57s} (1950)
GRB_DEC:         +54.583d {+54d 34' 60"} (J2000),
                 +54.521d {+54d 31' 15"} (current),
                 +54.862d {+54d 51' 42"} (1950)
GRB_ERROR:       4.53 [deg radius, statistical plus systematic]
GRB_INTEN:       1955 [cnts/sec]
DATA_SIGNIF:     16.00 [sigma]
INTEG_TIME:      0.128 [sec]
GRB_DATE:        15653 TJD;    92 DOY;   11/04/02
GRB_TIME:        778.54 SOD {00:12:58.54} UT
GRB_PHI:          79.00 [deg]
GRB_THETA:       145.00 [deg]
DATA_TIME_SCALE: 0.1280 [sec]
HARD_RATIO:      0.40
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       0,0,1, 0,0,0, 0,0,0, 0,1,0, 0,0,
SUN_POSTN:        10.96d {+00h 43m 50s}   +4.71d {+04d 42' 39"}
SUN_DIST:        120.33 [deg]   Sun_angle= -11.4 [hr] (East of Sun)
MOON_POSTN:      352.90d {+23h 31m 36s}   +2.35d {+02d 20' 52"}
MOON_DIST:       122.60 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      135.99, 61.44 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      152.26, 49.13 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 136.78,24.50 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:13:33 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     323395980
GRB_RA:          186.730d {+12h 26m 55s} (J2000),
                 186.864d {+12h 27m 27s} (current),
                 186.134d {+12h 24m 32s} (1950)
GRB_DEC:         +54.720d {+54d 43' 12"} (J2000),
                 +54.658d {+54d 39' 28"} (current),
                 +54.997d {+54d 59' 48"} (1950)
GRB_ERROR:       2.87 [deg radius, statistical only]
DATA_SIGNIF:     18.20 [sigma]
DATA_INTERVAL:   0.128 [sec]
GRB_DATE:        15653 TJD;    92 DOY;   11/04/02
GRB_TIME:        778.54 SOD {00:12:58.54} UT
GRB_PHI:          82.00 [deg]
GRB_THETA:       143.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   413 (Gnd S/W Version number)
SUN_POSTN:        10.96d {+00h 43m 50s}   +4.71d {+04d 42' 39"}
SUN_DIST:        120.53 [deg]   Sun_angle= -11.7 [hr] (East of Sun)
MOON_POSTN:      352.90d {+23h 31m 36s}   +2.35d {+02d 20' 54"}
MOON_DIST:       121.83 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      130.49, 62.05 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      155.40, 50.89 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        Bright hard burst in the GBM.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:14:23 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     450545,   Seg_Num: 0
GRB_RA:          197.419d {+13h 09m 41s} (J2000),
                 197.529d {+13h 10m 07s} (current),
                 196.929d {+13h 07m 43s} (1950)
GRB_DEC:         +61.242d {+61d 14' 30"} (J2000),
                 +61.182d {+61d 10' 55"} (current),
                 +61.508d {+61d 30' 28"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1480 [image_cnts]
TRIGGER_DUR:     72.000 [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:        15653 TJD;    92 DOY;   11/04/02
GRB_TIME:        777.18 SOD {00:12:57.18} UT
GRB_PHI:          28.11 [deg]
GRB_THETA:        48.06 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    11.87 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  +1  +0  +0 +40  +0 
SUN_POSTN:        10.96d {+00h 43m 50s}   +4.71d {+04d 42' 39"}
SUN_DIST:        113.91 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      352.91d {+23h 31m 38s}   +2.35d {+02d 21' 04"}
MOON_DIST:       113.70 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.75 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      154.74, 59.50 [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 = 225.26,10.99 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:17:01 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     450545,   Seg_Num: 0
GRB_RA:          197.419d {+13h 09m 41s} (J2000),
                 197.529d {+13h 10m 07s} (current),
                 196.929d {+13h 07m 43s} (1950)
GRB_DEC:         +61.242d {+61d 14' 30"} (J2000),
                 +61.182d {+61d 10' 55"} (current),
                 +61.508d {+61d 30' 28"} (1950)
GRB_DATE:        15653 TJD;    92 DOY;   11/04/02
GRB_TIME:        777.18 SOD {00:12:57.18} UT
TRIGGER_INDEX:   20000
GRB_PHI:          28.11 [deg]
GRB_THETA:        48.06 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     72.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    11.87 [sigma]
LC_URL:          sw00450545000msb.lc
SUN_POSTN:        10.96d {+00h 43m 51s}   +4.71d {+04d 42' 42"}
SUN_DIST:        113.91 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      352.93d {+23h 31m 42s}   +2.36d {+02d 21' 35"}
MOON_DIST:       113.69 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.75 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      154.74, 59.50 [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 = 225.26,10.99 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:22:07 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.422d {+13h 09m 41s} (J2000)
POINT_DEC:       +61.256d {+61d 15' 23"} (J2000)
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1321.50 SOD {00:22:01.50} UT,   544.3 [sec] since BAT Trigger Time
COUNTS:          1    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        0    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:37:42 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.421d {+13h 09m 41s} (J2000)
POINT_DEC:       +61.257d {+61d 15' 24"} (J2000)
POINT_ROLL:      7.055d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1325.02 SOD {00:22:05.02} UT,   547.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.595
N_STARS:         177
X_OFFSET:        386 [pixels]
Y_OFFSET:        632 [pixels]
X_MAX:           1345 [pixels]
Y_MAX:           1591 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00450545000msufc0547.fits
SUN_POSTN:        10.97d {+00h 43m 54s}   +4.72d {+04d 43' 02"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.08d {+23h 32m 20s}   +2.43d {+02d 25' 40"}
MOON_DIST:       113.65 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:38:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.421d {+13h 09m 41s} (J2000)
POINT_DEC:       +61.257d {+61d 15' 24"} (J2000)
POINT_ROLL:      7.055d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1325.02 SOD {00:22:05.02} UT,   547.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.595
N_STARS:         177
X_OFFSET:        386 [pixels]
Y_OFFSET:        632 [pixels]
X_MAX:           1345 [pixels]
Y_MAX:           1591 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00450545000msufc0547.fits
SUN_POSTN:        10.97d {+00h 43m 54s}   +4.72d {+04d 43' 02"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.09d {+23h 32m 21s}   +2.43d {+02d 25' 45"}
MOON_DIST:       113.65 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:39:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.421d {+13h 09m 41s} (J2000)
POINT_DEC:       +61.257d {+61d 15' 24"} (J2000)
ROLL:            7.055d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1325.02 SOD {00:22:05.02} UT,   547.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     323396531
X_OFFSET:        705 [pixels]
Y_OFFSET:        951 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       865
Y_GRB_POS:       1111
BINNING_INDEX:   1
IM_URL:          sw00450545000msuni0554.fits
SUN_POSTN:        10.98d {+00h 43m 54s}   +4.72d {+04d 43' 03"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.09d {+23h 32m 23s}   +2.43d {+02d 25' 57"}
MOON_DIST:       113.64 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:39:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.421d {+13h 09m 41s} (J2000)
POINT_DEC:       +61.257d {+61d 15' 24"} (J2000)
ROLL:            7.055d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1325.02 SOD {00:22:05.02} UT,   547.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     323396531
X_OFFSET:        705 [pixels]
Y_OFFSET:        951 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       865
Y_GRB_POS:       1111
BINNING_INDEX:   1
IM_URL:          sw00450545000msuni0554.fits
SUN_POSTN:        10.98d {+00h 43m 54s}   +4.72d {+04d 43' 04"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.10d {+23h 32m 23s}   +2.43d {+02d 26' 01"}
MOON_DIST:       113.64 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:40:38 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.416d {+13h 09m 40s} (J2000)
POINT_DEC:       +61.258d {+61d 15' 28"} (J2000)
POINT_ROLL:      7.049d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1659.22 SOD {00:27:39.22} UT,   882.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.598
N_STARS:         190
X_OFFSET:        146 [pixels]
Y_OFFSET:        392 [pixels]
X_MAX:           1585 [pixels]
Y_MAX:           1831 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00450545000msufc0882.fits
SUN_POSTN:        10.98d {+00h 43m 54s}   +4.72d {+04d 43' 05"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.10d {+23h 32m 25s}   +2.44d {+02d 26' 15"}
MOON_DIST:       113.64 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:41:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.416d {+13h 09m 40s} (J2000)
POINT_DEC:       +61.258d {+61d 15' 28"} (J2000)
POINT_ROLL:      7.049d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1659.22 SOD {00:27:39.22} UT,   882.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.598
N_STARS:         190
X_OFFSET:        146 [pixels]
Y_OFFSET:        392 [pixels]
X_MAX:           1585 [pixels]
Y_MAX:           1831 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00450545000msufc0882.fits
SUN_POSTN:        10.98d {+00h 43m 54s}   +4.72d {+04d 43' 05"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.11d {+23h 32m 26s}   +2.44d {+02d 26' 20"}
MOON_DIST:       113.64 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:42:09 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.416d {+13h 09m 40s} (J2000)
POINT_DEC:       +61.258d {+61d 15' 28"} (J2000)
ROLL:            7.049d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1659.22 SOD {00:27:39.22} UT,   882.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     323396866
X_OFFSET:        705 [pixels]
Y_OFFSET:        951 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       865
Y_GRB_POS:       1111
BINNING_INDEX:   1
IM_URL:          sw00450545000msuni0889.fits
SUN_POSTN:        10.98d {+00h 43m 55s}   +4.72d {+04d 43' 06"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.12d {+23h 32m 28s}   +2.44d {+02d 26' 33"}
MOON_DIST:       113.64 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:42:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     450545,   Seg_Num: 0
POINT_RA:        197.416d {+13h 09m 40s} (J2000)
POINT_DEC:       +61.258d {+61d 15' 28"} (J2000)
ROLL:            7.049d
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1659.22 SOD {00:27:39.22} UT,   882.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     323396866
X_OFFSET:        705 [pixels]
Y_OFFSET:        951 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       865
Y_GRB_POS:       1111
BINNING_INDEX:   1
IM_URL:          sw00450545000msuni0889.fits
SUN_POSTN:        10.98d {+00h 43m 55s}   +4.72d {+04d 43' 07"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.12d {+23h 32m 29s}   +2.44d {+02d 26' 37"}
MOON_DIST:       113.64 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.04, 55.73 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      154.72, 59.51 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 02 Apr 11 00:43:07 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     450545,   Seg_Num: 0
GRB_RA:          197.4019d {+13h 09m 36.45s} (J2000),
                 197.5118d {+13h 10m 02.83s} (current),
                 196.9119d {+13h 07m 38.86s} (1950)
GRB_DEC:         +61.2526d {+61d 15' 09.3"} (J2000),
                 +61.1929d {+61d 11' 34.2"} (current),
                 +61.5186d {+61d 31' 07.0"} (1950)
GRB_ERROR:       2.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  15653 TJD;    92 DOY;   11/04/02
IMG_START_TIME:  1334.00 SOD {00:22:14.00} UT,   556.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        10.98d {+00h 43m 55s}   +4.72d {+04d 43' 07"}
SUN_DIST:        113.89 [deg]   Sun_angle= 11.6 [hr] (West of Sun)
MOON_POSTN:      353.12d {+23h 32m 30s}   +2.45d {+02d 26' 44"}
MOON_DIST:       113.65 [deg]
MOON_ILLUM:      2 [%]
GAL_COORDS:      119.05, 55.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      154.72, 59.50 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 1.1% < P(seren) < 2.8%.

GCN Circular #11857
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), C. J. Saxton (UCL-MSSL), M. C. Stroh (PSU), C. A. Swenson (PSU) and E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:
At 00:12:57 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110402A (trigger=450545). Swift slewed to the burst at T+9 min. The BAT on-board calculated location is RA, Dec 197.419, +61.242 which is
```
   RA(J2000) = 13h 09m 41s
   Dec(J2000) = +61d 14' 30"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed multiple short spikes with a total duration of about 40 sec. The peak count rate was ~9000 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 00:22:01.5 UT, 544.3 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 197.4014, 61.2527 which is equivalent to:
```
   RA(J2000)  = 13h 09m 36.33s
   Dec(J2000) = +61d 15' 09.6"
```
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 49 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.62 x 10^20 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 547 seconds after the BAT trigger. No credible 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 19.6 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 0.02.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #11858
C.G. Mundell (Liverpool), A. Melandri (INAF-OAB) and N. Tanvir (Leicester) report on behalf of a larger collaboration:
"The 2-m Liverpool Telescope robotically followed up GRB110402 (SWIFT trigger 450545; Ukwatta et al. GCN 11857) 14.85 min after the GRB trigger time.
We identify a faint source detected within the XRT error circle in R, i' and z' band images at:
RA = 13:09:36.64 Dec = +61:15:09.7 +/-0.1" (J2000)
```
with  R = 20.8 (+/-0.1)    mag at t=28.0 min
      I = 20.75 (+/-0.17)  mag at t=33.0 min  (vs USNOB1)
```
Fading is yet to be confirmed.
This message may be cited"
GCN Circular #11859
G. Leloudas (DARK/NBI), D. Xu (WIS), P. Jakobsson (U. Iceland), M. Bayliss (U. Chicago/KICP), report on behalf of a larger collaboration:
We observed the field of GRB 110402A (Ukwatta et al., GCN 11857) with the Nordic Optical Telescope (La Palma, Spain) equipped with MOSCA.
Observations started at 01:26:09.0 UT (73.9 mins after the GRB). We obtained 3x300 s in the R filter. We detect a transient within the XRT error circle consistent with the position reported in Mundell et al. (GCN 11858).
Between the 1st and 3rd exposures, the optical transient shows marginal decay from 21.10 +- 0.02 to 21.17 +- 0.04 mag, calibrated with respect to the USNO B1 star 1512-0199231 (R1= 16.71 mag).
Since the object has also faded by 0.3 mag with respect to GCN 11858, we suggest that this is the afterglow of GRB 110402A.
GCN Circular #11860
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1602 s of XRT Photon Counting mode data and 4 UVOT images for GRB 110402A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 197.40226, +61.25285 which is equivalent to:
```
RA (J2000): 13h 09m 36.54s
Dec (J2000): +61d 15' 10.3"
```
with an uncertainty of 2.0 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #11861
A. N. Morgan, C. R. Klein, and J. S. Bloom (UC Berkeley) report:
We observed the field of GRB 110402A (Ukwatta et al., GCN 11857) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2011-04-02 04:28:41 UT, ~4.26 hours after the Swift Trigger. In mosaics (effective exposure time of 0.63 hours) taken simultaneously in the J and H filters, we do not detect any source at the optical afterglow location (Mundell et al., GCN 11858, Leloudas et al., GCN 11859). Our preliminary Ks band reduction is corrupted.
The preliminary photometry yields:
```
post burst
t_mid (hr) exp.(hr) filt  U. Limit (3 sig)
4.77       0.63     J     > 19.1
4.77       0.63     H     > 18.2
```
Further observations are ongoing to obtain a deeper limit. All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.
GCN Circular #11863
G. Leloudas (DARK/NBI), D. Xu (WIS), J. Hjorth (DARK/NBI), P. Jakobsson (U. Iceland), M. Bayliss (U. Chicago/KICP), report on behalf of a larger collaboration:
We re-observed the field of GRB 110402A (Ukwatta et al., GCN 11857) with the Nordic Optical Telescope (La Palma, Spain) equipped with MOSCA. We obtained two more 600 s R-band exposures starting at 02:38 UT and 04:24 UT.
In the table below we summarize all photometry obtained at the NOT, where we have also re-calibrated the photometry in Leloudas et al. (GCN 11859) based on several USNO B1.0 stars in the field:
```
t_start (min) 	R (mag)
83.1		21.15 +- 0.06
96.6		21.10 +- 0.08
145.5		21.10 +- 0.06
251.6		21.50 +- 0.07
```
The source has faded significantly between our last two observations confirming its transient nature.
GCN Circular #11864
M.Sokolowski,T.Batsch,A.Majcher,A.Majczyna,K.Nawrocki,J.Uzycki,G.Wrochna (IPJ, Swierk), M.Cwiok,W.Dominik,L.W.Piotrowski,A.F.Zarnecki (University of Warsaw), K.Malek,L.Mankiewicz,R.Opiela,M.Siudek,V.Repei (CFT PAN), G.Kasprowicz,M.Zaremba (Warsaw University of Technology), from the "Pi of the Sky" collaboration (http://grb.fuw.edu.pl ). M. Jelinek and A. J.Castro-Tirado (IAA-CSIC Granada) on behalf of a larger collaboration.
The wide field "Pi of the Sky North" apparatus installed in the BOOTES-1 station at ESAt/INTA-CEDEA in Mazagon (Huelva, Spain; http://grb.fuw.edu.pl/pi/index.html#piinta_site.htm ) observed field of GRB 110402A at the time of Fermi-GMB and Swift-BAT triggers. No new source brighter than 11 mag has been identified on 10s exposures:
```
t_start - t0      start (UT)  end (UT)     3-sigma limit

       -6           00:12:52    00:13:02     11.0
       +7           00:13:05    00:13:15     11.0
```
where limit is based on the reference star magnitudo in V filter.
GCN Circular #11865
C. Pagani (U. Leicester) and T. N. Ukwatta (MSU) report on behalf of the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 110402A (Ukwatta et al. GCN Circ. 11857), from 552 s to 24.7 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 11860).
The late-time light curve (from T0+6.4 ks) can be modelled with a power-law decay with a decay index of alpha=1.3 (+/-0.4).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.31 (+0.25, -0.27). The best-fitting absorption column is 10.0 (+2.9, -5.6) x 10^20 cm^-2, in excess of the Galactic value of 1.6 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     10.0 (+2.9, -5.6) x 10^20 cm^-2
Galactic foreground: 1.6 x 10^20 cm^-2
Excess significance: 2.9 sigma
Photon index:	     2.31 (+0.25, -0.27)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00450545.
This circular is an official product of the Swift-XRT team.
GCN Circular #11866
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. 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 110402A (trigger #450545) (Ukwatta, et al., GCN Circ. 11857). The BAT ground-calculated position is RA, Dec = 197.432, 61.247 deg, which is
```
   RA(J2000)  =  13h 09m 43.7s 
   Dec(J2000) = +61d 14' 49.6" 
```
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 10%.
The mask-weighted light curve shows 5 spikes (each with a duration less than 0.5 sec) with the first at ~T+1.5 sec and the last at ~T+6 sec. These are followed by softer emission out to ~T+90 sec. T90 (15-350 keV) is 60.9 +- 6.9 sec (estimated error including systematics).
The time-averaged spectrum from T-0.4 to T+69.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.59 +- 0.17. The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+3.18 sec in the 15-150 keV band is 4.1 +- 0.7 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/450545/BA/
GCN Circular #11868
J. Kelemen,(Konkoly Obs.) on behalf of the GRB OT observing program at the Konkoly Observatory.
We observed the field of GRB 110402A using the enhanced Swift-XRT position A.P. Beardmore et al. (GCN 11860) with a 60/90 cm Schmidt telescope located at the Mountain Station of the Konkoly Observatory. Within the XRT error circle we found an OT candidate at the position:
```
RA(2000) 13h 09m 36.64s
Dec(2000) +61d 15' 09.7" 
```
With an uncertainty of 0.15 arcsec.
For the photometry of the source on the coadded frames (total exp time 900 sec) nearby stars of the UCAC3 catalogue were used.
```
Time from 
the trigger    magnitude       Band
----------------------------------------
9523 sec      21.0 +/- 0.2      R 
```
Further observations planned.
GCN Circular #11869
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
The long GRB 110402A, (Swift/BAT trigger=3D450545: Ukwatta et al., GCN 11857; Stamatikos et.al, GCN 11866) triggered Konus-Wind at T0=3D00781.989s UT (00:13:01.989)
The burst light curve started with a hard multi-peaked pulse followed, after ~5s, by a softer decaying emission. The total duration of of the burst is ~70 s. The emission in the initial hard pulse is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110402_T00781/
As observed by Konus-Wind the burst had a fluence of (1.6 =B1 0.5)x10-5 erg/cm2, and a 16-ms peak flux, measured from T0, of (2.3 =B1 0.9)x10-5 erg/cm2/s (both in the 20 keV - 5 MeV energy range).
The time-integrated spectrum of the burst (from T0 to T0+65.792 s) is best fitted in the 20 keV - 5 MeV range by a simple power law function with the photon index (1.67 +- 0.09), chi2 = 86.6/78 dof.
The spectrum at the maximum count rate (measured from T0 to T0+0.256 s) is best fitted in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which alpha = -1.03 (-0.14, +0.16), and Ep = 1395(-604, +1835) keV, chi2 = 23.9/21 dof.
All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.
GCN Circular #11870
S.D. Barthelmy (GSFC) and J. Norris (BSU) report:
For GRB 110402A (Trigger 450545, GCNs 11857 & 11866), the spectral lag analysis of the Swift-BAT data from T+0.8 sec to T+6.0 sec (the initial 5 spikes), yields a lag of 3.7 +2.5/-2.9 msec for the 25-50 to 100-300 keV bands using a lightcurve binning of 4 msec. While the 5.2 sec duration for the 5 spikes is formally beyond the cononical 2-s boundary in duration for short bursts, the small lag value favors a short burst identification.
We note that there is on-going, much softer emission from T+5 to T+78 sec, and lacking sufficient structure to yield a significant lag measurement.
GCN Circular #11871
C. A. Swenson (PSU) and T. N. Ukwatta (MSU)report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 110402A 548 s after the BAT trigger (Ukwatta et al., GCN Circ. 11857). We find a faint new source consistent with the enhanced XRT position (Beardmore et al., GCN Circ. 11860).
Preliminary magnitudes and 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter        T_start(s)    T_stop(s)   Exp(s)    Mag
---------------------------------------------------------------------
white_FC         548           698       147     >20.5
white            548         24657      1628      20.89 =B10.11
v                704         18897       510     >20.1
b                803         24593      1544      20.84 =B10.20
u                778         30417       430     >20.6
w1               754         30390      1296      20.39 =B10.22
m2              7176          7376       197     >19.7
w2              6767         18791      1112      20.29 =B10.20
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) =3D 0.02 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #11873
D. Kuroda, (OAO, NAOJ), H. Hanayama (IAO, NAOJ), K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), T. Miyaji J. Watanabe, (IAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 110402A (Ukwatta et al., GCN 11857) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory and the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
We did not find any new point source within the enhanced XRT error circle (Beardmore et al., GCNC 11860) in all the three bands. We could not detect the previously reported afterglow (Mundell et al., GCN 11858).
Ishigakijima Astronomical Observatory: The observation started on 2011-04-02 12:18:01 UT, (~12.1 h after the burst).
```
T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.53014    12:56:21    3540.0    >21.4  >21.4  >20.4
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
Okayama Astrophysical Observatory: The observation started on 2011-04-02 13:51:58 UT, (13.7 h after the burst).
Three sigma upper limits of the OT are listed below. We used SDSS catalog for flux calibration.
```
T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.56634    13:48:29    8400.0    >19.6  >20.0  >19.4
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #11875
X. Bros, Agrupaci=C3=B3 Astron=C3=B2mica de Sabadell, Spain, has done a positive observation of GRB 110402A afterglow on three unfiltered images done from ANYSLLUM OBSERVATORY, Ager, Spain using a Newtonian reflector of 350mm f4.6.
```
1) exp 180 sec at 0h 52m 12 sec UT of 2011/04/02 (39 minutes 15 sec after SWIFT detection)
2) exp 300 sec at 0h 57m 26 sec UT (44 minutes 29 sec after SWIFT detection)
3) exp 300 sec at 1h 07m 48 sec UT (54 minutes 51 sec after SWIFT detection)
```
The afterglow is visible in all of these images. Position measured using UCAC 2 reference stars:
```
13h 09m 36.57s
+61d 15' 10.2"
```
Magnitude estimation on the combined add image (180sec+300sec+300sec) of 20.8CR, (unfiltered) using R reference stars from USNO A2.0 (18.7R, 18.8R, 19.5R). The image is linked in: http://anysllum.com/GRB%20110402A%20X%20Bros.jpg
[GCN OPS NOTE(04apr11). This circular was delayed in distribution for 15 hours while an account was set up.]
GCN Circular #11876
A. Volnova (SAI MSU), A. Pozanenko (IKI), E. Elunko (ISTP) on behalf of larger GRB follow up collaboration report:
We observed the field of GRB 110402A (Ukwatta et al. GCN 11857) with AZT-33IK telescope of Sayan observatory (Mondy) on April, 2 between (UT) 13:04:22 - 14:37:38 under moderate weather condition and seeing of about 2". In a stacked image we clearly detect optical counterpart (Mundell et al. GCN 11858, Leloudas et al. GCN 11859). The position of the counterpart is (J2000) RA= 13:09:36.42 Dec= +61:15:10.35 with uncertainty of 0,4" in both coordinates. The position is 1.7" apart from initial position reported by Mundell et al. (GCN 11858). The photometry is based on the USNO B1 star 1512-0199231 assuming R= 16.71
```
T0+         Filter,   Exposure, OT mag.,            UpperLimit (3 sigma)
(mid, d)              (s)

0.56809    R        5430    21.35 +/- 0.10       22.9
```
Since the position of counterpart is marginally different from initial position and the R-magnitude does not change since 251.6 minutes after burst (see Leloudas et al. GCN 11863) we can suggest that host galaxy dominates in our observations.
GCN Circular #11877
P. N. Bhat (UAH) reports on behalf of the Fermi GBM Team:
"At 00:12:58.54 UT on 02 April 2011, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 110402A (trigger 323395980 / 110402009). which was also detected by the Swift/BAT (Ukwatta et al. 2011, GCN 11857) The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 134.5 degrees.
The GBM light curve consists of multiple sharp pulses with a duration (T90) of about 36 s (50-300 keV). The time-averaged spectrum from T0-2.4 s to T0+59 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -1.29 +/- 0.07 and the cutoff energy, parameterized as Epeak, is 1025 +/- 409 keV
The event fluence (10-1000 keV) in this time interval is (1.3 +/- 0.06)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.8 s in the 10-1000 keV band is 7.82 +/- 0.47 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #11879
D. Frederiks and D. Svinkin on behalf of the Konus-Wind team, report:
1. The further analysis of the Konus-Wind detection (GCN 11869) of GRB 110402A (GCN 11857, 11866) confirms the zero spectral lag in the initial hard pulse reported with the Swift-BAT data (Barthelmy and Norris, GCN 11870). The following lag values between the Konus-Wind light curves are obtained:
```
-------------------------------------------------------------
LC1(keV)     LC2(keV)   Search Interval(s) Scale   Lag(ms)
-------------------------------------------------------------
G2(70-300)   G1(18-70)   -0.512:+0.320     8 ms   +3.5 =B1 12.5
G3(300-1160) G1(18-70)   -0.512:+0.280     8 ms   +3.2 =B1 12.3
G3(300-1160) G2(70-300)  -0.340:+0.320     4 ms   -0.3 =B1 4.8
-------------------------------------------------------------
```
The errors are given on 1 sigma level.
2. The total burst fluence S=3D(1.6 =B1 0.5)x10-5 erg/cm2 reported in GCN 11869 is divided between the hard initial pulse and the softer extended emission as follows: T0(-0.512 : +2.816) -> S1=3D(5.7 =B1 1.9)x10-6 erg/cm2 (initial pulse) T0(2.816 : +65.792) -> S2=3D(9.9 =B1 2.9)x10-6 erg/cm2 (extended emission= )
The K-W spectrum of the latter part (measured from T0+8.448s to T0+65.792s) can be fitted in the 20-5000 keV range by the simple power law function with the index of (1.81 =B1 0.13), chi2 =3D 93.4/78
The errors are given on 90% confidence level.
All times are given relative to K-W T0=3D781.989s UT.
GCN Circular #11885
Yiseul Jeon, Myungshin Im (SNU), and Yuji Urata (NCU)
We observed GRB 110402A (Ukwatta et al. GCN 11857) in R, I, z, and Y-bands using the 1 meter telescope at Mt. Lemmon, AZ, USA. The observations started at Arpil 2, 04:18:22UT(245.4 min after the BAT trigger), with the total integration time in each filter at 3 x 300 sec. A faint source is identified at the positon reported in Mundell et al. (GCN 11858). A preliminary analysis shows that the R-band magnitude is R=21.0 +- 0.3, calibrated using R2 magnitude of USNO-B1 stars in the vicinty.
We thank the LOAO operator, J. Yoon for his assistance for this observation.
[GCN OPS NOTE(05apr11): This circular was delay in distribution by ~10 hours waiting for a new accont to be enetered.]
GCN Circular #11887
T. Yasuda, Y. Terada, M. Tashiro, W. Iwakiri, K. Takahara (Saitama U.), T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.), N. Vasquez (Tokyo Tech.) K. Yamaoka (Aoyama Gakuin U.), S. Sugita (Nagoya U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), Y. E. Nakagawa, T. Tamagawa (RIKEN), N. Ohmori, M. Yamauchi (Univ. of Miyazaki), Y. Urata, P. Tsai (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report:
The GRB 110402A (Swift/BAT trigger #450545; Ukwatta et al.) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2011-04-02 00:12:58.49 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0-1.5s, ending at T0+83.5s, with a duration (T90) of about 70 seconds. The fluence in 100 - 1000 keV was 9.1 (+0.9, -0.9) x 10^-6 erg/cm^2.
The 1-s peak flux measured from T0+1s was 5.72 photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from T0-1.5 s to T0+83.5 s is well fitted by a single power-law with a photon index of 1.57 (+0.11, -0.10) (chi^2/d.o.f = 44.73/31).
All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included.
The light curves for this burst will be update at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN Circular #11888
R. Ruffini, L. Izzo, A.V. Penacchioni, C.L. Bianco (ICRANet, ICRA and Rome University "La Sapienza") report:
From theoretical considerations on the transparency of the P-GRB (between t0 and t0+6 s), we infer for GRB 110402A a redshift z between 2.02 and 2.48. We strongly encourage a spectroscopic identification of the redshift.
GCN Circular #11889
V. Rumyantsev (CrAO), A. Pozanenko (IKI), A. Volnova (SAI MSU) on behalf of larger GRB follow up collaboration report:
We observed the field of GRB 110402A (Ukwatta et al. GCN 11857) with Shajn telescope of CrAO observatory on Apr. 3 between (UT) 18:41 and 19:59 under seeing of about 2.6 arsces. We took several frames with exposure of 60s in R-band. On a stacked image we detected the optical counterpart (Mundell et al. GCN 11858, Leloudas et al. GCN 11859). The counterpart has coordinates (J2000) RA = 13h 09m 36.63s, Dec = +61d 15' 09.5'' with uncertainty of 0.1" in both coordinates which are fully compatible with initial counterpart coordinates (Mundell et al. GCN 11858). The photometry is based on the USNO B1.0 star 1512-0199231 (13 09 43.16 +61 14 38.5) assuming R=16.71.
```
T0+         Filter,   Exposure, mag.                uplim (3 sigma)
(mid, d)               (s)

1.79672  R         73x60       23.11+/-0.12  24.4 
```
GCN Circular #11892
R. Ruffini, L. Izzo, A.V. Penacchioni, C.L. Bianco (ICRANet, ICRA and Rome University "La Sapienza") report:
A more accurate evaluation of GRB 110402A rebinned data leads to an estimate of the redshift z between 0.7 and 1.0.
GCN Report 331.1
GCN_Report 331.1 has been posted: http://gcn.gsfc.nasa.gov/reports/report_331_1.pdf by T.N. Ukwatta at MSU titled: "Final Report on Swift GRB 110402A"
Redshift z= 0.854 +- 0.001 from host galaxy emission ([OII])
B. O'Connor et al. 2022, MN 515, 4890

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Jochen Greiner, last update: 16-Jan-2023 [Disclaimer]