Gamma-ray Burst 150428B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:12:38 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     639278,   Seg_Num: 0
GRB_RA:          292.654d {+19h 30m 37s} (J2000),
                 292.845d {+19h 31m 23s} (current),
                 292.032d {+19h 28m 08s} (1950)
GRB_DEC:          +4.116d {+04d 06' 57"} (J2000),
                  +4.149d {+04d 08' 55"} (current),
                  +4.010d {+04d 00' 36"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       6986 [cnts]    Image_Peak=204 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   473     E_range: 25-100 keV
BKG_INTEN:       69057 [cnts]
BKG_TIME:        11490.49 SOD {03:11:30.49} UT
BKG_DUR:         24 [sec]
GRB_DATE:        17140 TJD;   118 DOY;   15/04/28
GRB_TIME:        11523.51 SOD {03:12:03.51} UT
GRB_PHI:         -154.61 [deg]
GRB_THETA:        43.55 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.24 [sigma]
IMAGE_SIGNIF:    7.45 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +2  -2  +0  +1 +18  +0 
SUN_POSTN:        35.18d {+02h 20m 43s}  +14.02d {+14d 01' 25"}
SUN_DIST:        100.91 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.89d {+10h 07m 35s}   +7.98d {+07d 58' 36"}
MOON_DIST:       139.20 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.79 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      295.21, 25.59 [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 = 12.34,20.51 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:14:16 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     639278,   Seg_Num: 0
GRB_RA:          292.6379d {+19h 30m 33.09s} (J2000),
                 292.8285d {+19h 31m 18.83s} (current),
                 292.0157d {+19h 28m 03.77s} (1950)
GRB_DEC:          +4.1253d {+04d 07' 31.0"} (J2000),
                  +4.1583d {+04d 09' 29.7"} (current),
                  +4.0195d {+04d 01' 10.3"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       8.91e-09 [erg/cm2/sec]
GRB_SIGNIF:      13.30 [sigma]
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11630.99 SOD {03:13:50.99} UT,   107.5 [sec] since BAT Trigger Time
TAM[0-3]:        327.68 237.15 261.56 243.81
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:        35.18d {+02h 20m 43s}  +14.02d {+14d 01' 27"}
SUN_DIST:        100.92 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.91d {+10h 07m 38s}   +7.97d {+07d 58' 22"}
MOON_DIST:       139.17 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the burst
ECL_COORDS:      295.20, 25.61 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.14 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:14:35 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     639278,   Seg_Num: 0
GRB_RA:          292.6379d {+19h 30m 33.0s} (J2000),
                 292.8285d {+19h 31m 18.8s} (current),
                 292.0157d {+19h 28m 03.7s} (1950)
GRB_DEC:          +4.1253d {+04d 07' 31.0"} (J2000),
                  +4.1583d {+04d 09' 29.7"} (current),
                  +4.0195d {+04d 01' 10.3"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       177 [cnts]
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11630.99 SOD {03:13:50.99} UT,   107.5 [sec] since BAT Trigger Time
CENTROID_X:      300.03,  raw= 300  [pixels]
CENTROID_Y:      283.87,  raw= 284  [pixels]
ROLL:            74.78 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -32.82
GRB_POS_XRT_Z:   -12.40
IMAGE_URL:       sw00639278000msxps_rw.img
SUN_POSTN:        35.18d {+02h 20m 44s}  +14.02d {+14d 01' 27"}
SUN_DIST:        100.92 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.91d {+10h 07m 38s}   +7.97d {+07d 58' 19"}
MOON_DIST:       139.17 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the burst
ECL_COORDS:      295.20, 25.61 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:14:32 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     639278,   Seg_Num: 0
GRB_RA:          292.6379d {+19h 30m 33.0s} (J2000),
                 292.8285d {+19h 31m 18.8s} (current),
                 292.0157d {+19h 28m 03.7s} (1950)
GRB_DEC:          +4.1253d {+04d 07' 31.0"} (J2000),
                  +4.1583d {+04d 09' 29.7"} (current),
                  +4.0195d {+04d 01' 10.3"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       177 [cnts]
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11630.99 SOD {03:13:50.99} UT,   107.5 [sec] since BAT Trigger Time
CENTROID_X:      300.03,  raw= 300  [pixels]
CENTROID_Y:      283.87,  raw= 284  [pixels]
ROLL:            74.78 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -32.82
GRB_POS_XRT_Z:   -12.40
IMAGE_URL:       sw00639278000msxps_rw.img
SUN_POSTN:        35.18d {+02h 20m 44s}  +14.02d {+14d 01' 27"}
SUN_DIST:        100.92 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.91d {+10h 07m 38s}   +7.97d {+07d 58' 20"}
MOON_DIST:       139.17 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the burst
ECL_COORDS:      295.20, 25.61 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:16:04 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     639278,   Seg_Num: 0
GRB_RA:          292.654d {+19h 30m 37s} (J2000),
                 292.845d {+19h 31m 23s} (current),
                 292.032d {+19h 28m 08s} (1950)
GRB_DEC:          +4.116d {+04d 06' 57"} (J2000),
                  +4.149d {+04d 08' 55"} (current),
                  +4.010d {+04d 00' 36"} (1950)
GRB_DATE:        17140 TJD;   118 DOY;   15/04/28
GRB_TIME:        11523.51 SOD {03:12:03.51} UT
TRIGGER_INDEX:   473
GRB_PHI:         -154.61 [deg]
GRB_THETA:        43.55 [deg]
DELTA_TIME:      57.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.24 [sigma]
IMAGE_SIGNIF:    7.45 [sigma]
LC_URL:          sw00639278000msb.lc
SUN_POSTN:        35.18d {+02h 20m 44s}  +14.02d {+14d 01' 28"}
SUN_DIST:        100.91 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.92d {+10h 07m 41s}   +7.97d {+07d 58' 07"}
MOON_DIST:       139.18 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.79 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      295.21, 25.59 [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 = 12.34,20.51 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:17:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.633d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.134d {+04d 08' 01"} (J2000)
POINT_ROLL:      74.782d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11640.53 SOD {03:14:00.53} UT,   117.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.543
N_STARS:         190
X_OFFSET:        664 [pixels]
Y_OFFSET:        624 [pixels]
X_MAX:           1623 [pixels]
Y_MAX:           1583 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00639278000msufc0117.fits
SUN_POSTN:        35.18d {+02h 20m 44s}  +14.02d {+14d 01' 29"}
SUN_DIST:        100.92 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.93d {+10h 07m 43s}   +7.97d {+07d 57' 57"}
MOON_DIST:       139.15 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.12, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.62 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:17:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.633d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.134d {+04d 08' 01"} (J2000)
POINT_ROLL:      74.782d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11640.53 SOD {03:14:00.53} UT,   117.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.543
N_STARS:         190
X_OFFSET:        664 [pixels]
Y_OFFSET:        624 [pixels]
X_MAX:           1623 [pixels]
Y_MAX:           1583 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00639278000msufc0117.fits
SUN_POSTN:        35.18d {+02h 20m 44s}  +14.02d {+14d 01' 29"}
SUN_DIST:        100.92 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.93d {+10h 07m 44s}   +7.96d {+07d 57' 53"}
MOON_DIST:       139.14 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.12, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.62 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:19:08 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.633d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.134d {+04d 08' 01"} (J2000)
ROLL:            74.782d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11640.53 SOD {03:14:00.53} UT,   117.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     451883654
X_OFFSET:        854 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1014
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00639278000msuni0131.fits
SUN_POSTN:        35.18d {+02h 20m 44s}  +14.03d {+14d 01' 30"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.95d {+10h 07m 47s}   +7.96d {+07d 57' 41"}
MOON_DIST:       139.13 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.12, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.62 [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:     Tue 28 Apr 15 03:19:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.633d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.134d {+04d 08' 01"} (J2000)
ROLL:            74.782d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11640.53 SOD {03:14:00.53} UT,   117.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     451883654
X_OFFSET:        854 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1014
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00639278000msuni0131.fits
SUN_POSTN:        35.18d {+02h 20m 44s}  +14.03d {+14d 01' 31"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.95d {+10h 07m 48s}   +7.96d {+07d 57' 38"}
MOON_DIST:       139.13 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.12, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.62 [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:     Tue 28 Apr 15 03:25:17 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
POINT_ROLL:      74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11852.62 SOD {03:17:32.62} UT,   329.1 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.031
N_STARS:         190
X_OFFSET:        534 [pixels]
Y_OFFSET:        587 [pixels]
X_MAX:           1493 [pixels]
Y_MAX:           1546 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00639278000msufc0329.fits
SUN_POSTN:        35.19d {+02h 20m 45s}  +14.03d {+14d 01' 35"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      151.99d {+10h 07m 59s}   +7.95d {+07d 56' 49"}
MOON_DIST:       139.09 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:25:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
POINT_ROLL:      74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11852.62 SOD {03:17:32.62} UT,   329.1 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.031
N_STARS:         190
X_OFFSET:        534 [pixels]
Y_OFFSET:        587 [pixels]
X_MAX:           1493 [pixels]
Y_MAX:           1546 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00639278000msufc0329.fits
SUN_POSTN:        35.19d {+02h 20m 45s}  +14.03d {+14d 01' 36"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      152.00d {+10h 08m 00s}   +7.95d {+07d 56' 45"}
MOON_DIST:       139.09 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:26:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
ROLL:            74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11852.62 SOD {03:17:32.62} UT,   329.1 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     451883866
X_OFFSET:        854 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1014
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00639278000msuni0343.fits
SUN_POSTN:        35.19d {+02h 20m 45s}  +14.03d {+14d 01' 36"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      152.01d {+10h 08m 01s}   +7.94d {+07d 56' 37"}
MOON_DIST:       139.08 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [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:     Tue 28 Apr 15 03:27:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 32s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
ROLL:            74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  11852.62 SOD {03:17:32.62} UT,   329.1 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     451883866
X_OFFSET:        854 [pixels]
Y_OFFSET:        907 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1014
Y_GRB_POS:       1067
BINNING_INDEX:   1
IM_URL:          sw00639278000msuni0343.fits
SUN_POSTN:        35.19d {+02h 20m 46s}  +14.03d {+14d 01' 37"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      152.01d {+10h 08m 02s}   +7.94d {+07d 56' 34"}
MOON_DIST:       139.08 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [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:     Tue 28 Apr 15 03:30:20 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 31s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
POINT_ROLL:      74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  12382.77 SOD {03:26:22.77} UT,   859.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.276
N_STARS:         190
X_OFFSET:        294 [pixels]
Y_OFFSET:        347 [pixels]
X_MAX:           1733 [pixels]
Y_MAX:           1786 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00639278000msufc0859.fits
SUN_POSTN:        35.19d {+02h 20m 46s}  +14.03d {+14d 01' 39"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      152.03d {+10h 08m 08s}   +7.94d {+07d 56' 07"}
MOON_DIST:       139.05 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:30:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 31s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
POINT_ROLL:      74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  12382.77 SOD {03:26:22.77} UT,   859.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.276
N_STARS:         190
X_OFFSET:        294 [pixels]
Y_OFFSET:        347 [pixels]
X_MAX:           1733 [pixels]
Y_MAX:           1786 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00639278000msufc0859.fits
SUN_POSTN:        35.19d {+02h 20m 46s}  +14.03d {+14d 01' 40"}
SUN_DIST:        100.93 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      152.04d {+10h 08m 09s}   +7.93d {+07d 56' 04"}
MOON_DIST:       139.05 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:31:58 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 31s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
ROLL:            74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  12382.77 SOD {03:26:22.77} UT,   859.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     451884396
X_OFFSET:        853 [pixels]
Y_OFFSET:        906 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1066
BINNING_INDEX:   1
IM_URL:          sw00639278000msuni0873.fits
SUN_POSTN:        35.19d {+02h 20m 46s}  +14.03d {+14d 01' 41"}
SUN_DIST:        100.94 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      152.05d {+10h 08m 11s}   +7.93d {+07d 55' 53"}
MOON_DIST:       139.04 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Apr 15 03:32:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     639278,   Seg_Num: 0
POINT_RA:        292.631d {+19h 30m 31s} (J2000)
POINT_DEC:        +4.131d {+04d 07' 53"} (J2000)
ROLL:            74.784d
IMG_START_DATE:  17140 TJD;   118 DOY;   15/04/28
IMG_START_TIME:  12382.77 SOD {03:26:22.77} UT,   859.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     451884396
X_OFFSET:        853 [pixels]
Y_OFFSET:        906 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1066
BINNING_INDEX:   1
IM_URL:          sw00639278000msuni0873.fits
SUN_POSTN:        35.19d {+02h 20m 46s}  +14.03d {+14d 01' 41"}
SUN_DIST:        100.94 [deg]   Sun_angle= 6.8 [hr] (West of Sun)
MOON_POSTN:      152.05d {+10h 08m 12s}   +7.93d {+07d 55' 51"}
MOON_DIST:       139.04 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:       41.11, -6.77 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      295.19, 25.61 [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 #17766
K. L. Page (U Leicester), M. M. Chester (PSU), F. E. Marshall (NASA/GSFC), T. Sakamoto (AGU) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 03:12:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150428B (trigger=639278). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 292.654, +4.116 which is
```
   RA(J2000) = 19h 30m 37s
   Dec(J2000) = +04d 06' 57"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 30 sec. The peak count rate was ~1800 counts/sec (15-350 keV), at ~3 sec after the trigger.
The XRT began observing the field at 03:13:50.9 UT, 107.5 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 292.63764, 4.12529 which is equivalent to:
```
   RA(J2000)  = 19h 30m 33.03s
   Dec(J2000) = +04d 07' 31.0"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 67 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 3.26 x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 8.91e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 117 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. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.40.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). 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 #17773
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1321 s of XRT Photon Counting mode data and 1 UVOT images for GRB 150428B, 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 = 292.63941, +4.12505 which is equivalent to:
```
RA (J2000): 19h 30m 33.46s
Dec (J2000): +04d 07' 30.2"
```
with an uncertainty of 1.6 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 #17776
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):=20
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150428B (trigger #639278) (Page, et al., GCN Circ. 17766). The BAT ground-calculated position is RA, Dec =3D 292.661, 4.114 deg which is
```
 RA(J2000)  =  19h 30m 38.8s
 Dec(J2000) = +04d 06' 52.2
```
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 40%.
The mask-weighted light curve shows three peaks. The first peak starts at T-40 sec, peaks at T-25 sec and ends at T-20 sec. The second peak starts at T-15 sec, peaks=20 at T+5 sec and ends at T+50 sec. And the third peak starts at T+55 sec, peaks at T+65 sec and ends at T+120 sec. T90 (15-350 keV) is 130.9 +- 15.6 sec (estimated error including systematics).
The time-averaged spectrum from T-40.1 to T+121.7 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.0 +- 0.5, and Epeak of 55 +- 10 keV (chi squared 37.44 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.7 +- 0.3 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+1.36 sec in the 15-150 keV band is 1.5 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.87 +- 0.10 (chi squared 49.44 for 57 d.o.f.). 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/639278/BA/
GCN Circular #17780
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
MASTER II robotic telescope (MASTER-SAAO: http://observ.pereplet.ru) located in SAAO was pointed to the GRB150428B 24 sec after notice time and 59 sec after trigger time at 2015-04-28 03:13:03 UT in two polarizations. On our first (10s exposure) set we haven`t found optical transient within SWIFT BAT (Page et. al GCN 17766) and XRT (Beardmore et al. GCN 17773) error-boxes . We have 3x2 images during Gamma Ray activity (see Page et al., GCN 17777) in two polarizations. So our observations is prompt observations. We obtain a followin upper limits on single and coadd images:
```
Date start  T_start -T_trig  T_mid-T_trig  Expt.  Limit Coadd

03:13:03.3        59             64         10    16.5   no
03:13:03.3        59             97         50    17.4    3
03:13:03.3        59            529        810    19.3   12
```
Data analysis was hampered by a high density of stars in the error box. XRT position covered by bright (~15m) star USNO B1 0941-0468603.
The message may be cited.
GCN Circular #17781
P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U. Leicester), A. Amaral-Rogers (U. Leicester), J.P. Osborne (U. Leicester), M. de Pasquale (INAF-IASFPA) and K.L. Page report on behalf of the Swift-XRT team:
We have analysed 8.3 ks of XRT data for GRB 150428B (Page et al. GCN Circ. 17766), from 100 s to 34.4 ks after the BAT trigger. The data comprise 187 s in Windowed Timing (WT) mode (the first 6 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 17773).
The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=2.31 (+0.16, -0.20). At T+170 s the decay steepens to an alpha of 4.92 (+0.15, -0.16) before breaking again at T+618 s to a final decay with index alpha=0.29 (+/-0.07).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.93 (+0.06, -0.05). The best-fitting absorption column is 3.51 (+0.28, -0.25) x 10^21 cm^-2, consistent with the Galactic value of 3.3 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.90 (+0.16, -0.08) and a best-fitting absorption column consistent with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (5.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.3 (+0.3, -0.0) x 10^21 cm^-2
Galactic foreground: 3.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.90 (+0.16, -0.08)
```
If the light curve continues to decay with a power-law decay index of 0.29, the count rate at T+24 hours will be 0.027 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x 10^-12 (1.5 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00639278.
This circular is an official product of the Swift-XRT team.
GCN Circular #17787
M. M. Chester (PSU) and K. L. Page (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150428B 117 s after the BAT trigger (Page et al., GCN Circ. 17766). No optical afterglow consistent with the enhanced XRT position (Beardmore et al., GCN Circ. 17773) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposures and subsequent exposures are:
```
Filter      T_start(s)   T_stop(s)   Exp(s)    UL (3-sigma)

white_FC       117          267        146       >20.9
u_FC           329          579        246       >20.1
white          117         5414        588       >21.6
v              659         5825        313       >19.6
b              584         6598        445       >20.8
u              329         6440        717       >20.8
w1             708         6235        293       >20.0
m2             683         6030        294       >19.9
w2             634         5620        313       >20.2
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.40 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #17788
K. L. Murata (Nagoya U.), S. Nishiyama, A. Iwamatsu, I. Kawamata (Miyagi University of Education), and T. Nagayama (Kagoshima U.)
We observed the field of GRB 150428B ( Page et al., GCN Circular #17766) with the near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS attached to 1.4 m telescope IRSF ( InfraRed Survey Facility) in Sutherland observatory, South Africa.
The observations started on 2015-04-28 03:59:59 UT (~ 48 min. after the burst). We could not detect the afterglow within the XRT error circle reported in the GCN circular in the three bands. We have obtained the following preliminary upper limits (Vega magnitude system):
```
 J  > 17.4
 H  > 16.8
 Ks > 15.3.
```
Given magnitudes were calibrated against 2MASS point sources in this field. The upper limits were determined as the magnitudes of the faintest star within 1 arcmin from the XRT position.
This observation was carried out by IRSF and OISTER collaboration.

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Jochen Greiner, last update: 30-Apr-2015 [Disclaimer]