Gamma-ray Burst 170526A

(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 26 May 17 13:36:15 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     754549,   Seg_Num: 0
GRB_RA:            4.708d {+00h 18m 50s} (J2000),
                   4.931d {+00h 19m 43s} (current),
                   4.067d {+00h 16m 16s} (1950)
GRB_DEC:          +1.240d {+01d 14' 22"} (J2000),
                  +1.336d {+01d 20' 10"} (current),
                  +0.962d {+00d 57' 43"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       14422 [cnts]    Image_Peak=314 [image_cnts]
TRIGGER_DUR:     5.504 [sec] 
TRIGGER_INDEX:   476     E_range: 25-100 keV
BKG_INTEN:       115592 [cnts]
BKG_TIME:        48836.88 SOD {13:33:56.88} UT
BKG_DUR:         48 [sec]
GRB_DATE:        17899 TJD;   146 DOY;   17/05/26
GRB_TIME:        48908.94 SOD {13:35:08.94} UT
GRB_PHI:         158.22 [deg]
GRB_THETA:        18.21 [deg]
SOLN_STATUS:     0x83
RATE_SIGNIF:     8.88 [sigma]
IMAGE_SIGNIF:    6.86 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +2  -3  +0  +0 -49  +0 
SUN_POSTN:        63.59d {+04h 14m 20s}  +21.22d {+21d 13' 04"}
SUN_DIST:         60.45 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.55d {+05h 02m 12s}  +18.02d {+18d 01' 07"}
MOON_DIST:        71.17 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.17,-60.57 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        4.81, -0.73 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 333.48,14.51 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 26 May 17 13:37:20 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.702d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.237d {+01d 14' 14"} (J2000)
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49033.20 SOD {13:37:13.20} UT,   124.3 [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:     Fri 26 May 17 13:39:04 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     754549,   Seg_Num: 0
GRB_RA:            4.708d {+00h 18m 50s} (J2000),
                   4.931d {+00h 19m 43s} (current),
                   4.067d {+00h 16m 16s} (1950)
GRB_DEC:          +1.240d {+01d 14' 22"} (J2000),
                  +1.336d {+01d 20' 10"} (current),
                  +0.962d {+00d 57' 43"} (1950)
GRB_DATE:        17899 TJD;   146 DOY;   17/05/26
GRB_TIME:        48908.94 SOD {13:35:08.94} UT
TRIGGER_INDEX:   476
GRB_PHI:         158.22 [deg]
GRB_THETA:        18.21 [deg]
DELTA_TIME:      -5.00 [sec]
TRIGGER_DUR:     5.504 [sec] 
SOLN_STATUS:     0x83
RATE_SIGNIF:     8.88 [sigma]
IMAGE_SIGNIF:    6.86 [sigma]
LC_URL:          sw00754549000msb.lc
SUN_POSTN:        63.59d {+04h 14m 21s}  +21.22d {+21d 13' 06"}
SUN_DIST:         60.45 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.58d {+05h 02m 19s}  +18.02d {+18d 01' 21"}
MOON_DIST:        71.20 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.17,-60.57 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        4.81, -0.73 [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:        Since the IMAGE_SIGNIF is less than 7 sigma, this is a questionable detection.  
COMMENTS:        This trigger occurred at longitude,latitude = 333.48,14.51 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 26 May 17 13:43:45 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     754549,   Seg_Num: 0
GRB_RA:            4.7069d {+00h 18m 49.65s} (J2000),
                   4.9300d {+00h 19m 43.20s} (current),
                   4.0660d {+00h 16m 15.82s} (1950)
GRB_DEC:          +1.2775d {+01d 16' 39.0"} (J2000),
                  +1.3740d {+01d 22' 26.4"} (current),
                  +0.9999d {+00d 59' 59.6"} (1950)
GRB_ERROR:       5.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49041.00 SOD {13:37:21.00} UT,   132.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        63.59d {+04h 14m 22s}  +21.22d {+21d 13' 08"}
SUN_DIST:         60.44 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.63d {+05h 02m 31s}  +18.03d {+18d 01' 43"}
MOON_DIST:        71.24 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.18,-60.53 [deg] galactic lon,lat of the burst
ECL_COORDS:        4.83, -0.70 [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:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 1.1% < P(seren) < 2.8%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 26 May 17 13:45:41 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.703d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.237d {+01d 14' 14"} (J2000)
POINT_ROLL:      66.212d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49036.72 SOD {13:37:16.72} UT,   127.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.488
N_STARS:         9
X_OFFSET:        502 [pixels]
Y_OFFSET:        530 [pixels]
X_MAX:           1461 [pixels]
Y_MAX:           1489 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    16
SL_URL:          sw00754549000msufc0127.fits
SUN_POSTN:        63.59d {+04h 14m 22s}  +21.22d {+21d 13' 08"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.65d {+05h 02m 36s}  +18.03d {+18d 01' 52"}
MOON_DIST:        71.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 26 May 17 13:45:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.703d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.237d {+01d 14' 14"} (J2000)
POINT_ROLL:      66.212d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49036.72 SOD {13:37:16.72} UT,   127.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.488
N_STARS:         9
X_OFFSET:        502 [pixels]
Y_OFFSET:        530 [pixels]
X_MAX:           1461 [pixels]
Y_MAX:           1489 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    16
SL_URL:          sw00754549000msufc0127.fits
SUN_POSTN:        63.59d {+04h 14m 22s}  +21.22d {+21d 13' 08"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.65d {+05h 02m 37s}  +18.03d {+18d 01' 52"}
MOON_DIST:        71.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [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 26 May 17 13:47:18 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.703d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.237d {+01d 14' 14"} (J2000)
ROLL:            66.212d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49036.72 SOD {13:37:16.72} UT,   127.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     517498655
X_OFFSET:        821 [pixels]
Y_OFFSET:        849 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       981
Y_GRB_POS:       1009
BINNING_INDEX:   1
IM_URL:          sw00754549000msuni0147.fits
SUN_POSTN:        63.59d {+04h 14m 22s}  +21.22d {+21d 13' 09"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.67d {+05h 02m 41s}  +18.03d {+18d 01' 59"}
MOON_DIST:        71.29 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [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 26 May 17 13:47:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.703d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.237d {+01d 14' 14"} (J2000)
ROLL:            66.212d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49036.72 SOD {13:37:16.72} UT,   127.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     517498655
X_OFFSET:        821 [pixels]
Y_OFFSET:        849 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       981
Y_GRB_POS:       1009
BINNING_INDEX:   1
IM_URL:          sw00754549000msuni0147.fits
SUN_POSTN:        63.59d {+04h 14m 22s}  +21.22d {+21d 13' 09"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.67d {+05h 02m 41s}  +18.03d {+18d 02' 00"}
MOON_DIST:        71.30 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [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:     Fri 26 May 17 13:49:29 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.704d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.236d {+01d 14' 11"} (J2000)
POINT_ROLL:      66.210d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49194.59 SOD {13:39:54.59} UT,   285.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        3.569
N_STARS:         21
X_OFFSET:        262 [pixels]
Y_OFFSET:        290 [pixels]
X_MAX:           1701 [pixels]
Y_MAX:           1729 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00754549000msufc0285.fits
SUN_POSTN:        63.59d {+04h 14m 23s}  +21.22d {+21d 13' 10"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.69d {+05h 02m 47s}  +18.04d {+18d 02' 10"}
MOON_DIST:        71.32 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 26 May 17 13:49:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.704d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.236d {+01d 14' 11"} (J2000)
POINT_ROLL:      66.210d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49194.59 SOD {13:39:54.59} UT,   285.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        3.569
N_STARS:         21
X_OFFSET:        262 [pixels]
Y_OFFSET:        290 [pixels]
X_MAX:           1701 [pixels]
Y_MAX:           1729 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00754549000msufc0285.fits
SUN_POSTN:        63.59d {+04h 14m 23s}  +21.22d {+21d 13' 10"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.70d {+05h 02m 47s}  +18.04d {+18d 02' 10"}
MOON_DIST:        71.32 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [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 26 May 17 13:50:15 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     754549,   Seg_Num: 0
GRB_RA:            4.7073d {+00h 18m 49.75s} (J2000),
                   4.9304d {+00h 19m 43.30s} (current),
                   4.0664d {+00h 16m 15.92s} (1950)
GRB_DEC:          +1.2773d {+01d 16' 38.2"} (J2000),
                  +1.3738d {+01d 22' 25.7"} (current),
                  +0.9997d {+00d 59' 58.9"} (1950)
GRB_ERROR:       4.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49041.00 SOD {13:37:21.00} UT,   132.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        63.60d {+04h 14m 23s}  +21.22d {+21d 13' 10"}
SUN_DIST:         60.44 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.70d {+05h 02m 49s}  +18.04d {+18d 02' 13"}
MOON_DIST:        71.31 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.18,-60.53 [deg] galactic lon,lat of the burst
ECL_COORDS:        4.83, -0.70 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 26 May 17 13:51:02 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.704d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.236d {+01d 14' 11"} (J2000)
ROLL:            66.210d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49194.59 SOD {13:39:54.59} UT,   285.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     517498813
X_OFFSET:        821 [pixels]
Y_OFFSET:        849 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       981
Y_GRB_POS:       1009
BINNING_INDEX:   1
IM_URL:          sw00754549000msuni0305.fits
SUN_POSTN:        63.60d {+04h 14m 23s}  +21.22d {+21d 13' 11"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.71d {+05h 02m 51s}  +18.04d {+18d 02' 17"}
MOON_DIST:        71.33 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [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 26 May 17 13:51:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     754549,   Seg_Num: 0
POINT_RA:          4.704d {+00h 18m 49s} (J2000)
POINT_DEC:        +1.236d {+01d 14' 11"} (J2000)
ROLL:            66.210d
IMG_START_DATE:  17899 TJD;   146 DOY;   17/05/26
IMG_START_TIME:  49194.59 SOD {13:39:54.59} UT,   285.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     517498813
X_OFFSET:        821 [pixels]
Y_OFFSET:        849 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       981
Y_GRB_POS:       1009
BINNING_INDEX:   1
IM_URL:          sw00754549000msuni0305.fits
SUN_POSTN:        63.60d {+04h 14m 23s}  +21.22d {+21d 13' 11"}
SUN_DIST:         60.46 [deg]   Sun_angle= 3.9 [hr] (West of Sun)
MOON_POSTN:       75.71d {+05h 02m 51s}  +18.04d {+18d 02' 18"}
MOON_DIST:        71.33 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      106.16,-60.57 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:        4.81, -0.73 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #21149
B. Sbarufatti (INAF-OAB/PSU), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), C. Gronwall (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 13:35:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170526A (trigger=754549). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 4.708, +1.240 which is
```
   RA(J2000)  =  00h 18m 50s
   Dec(J2000) = +01d 14' 22"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 8 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 13:37:13.2 UT, 124.3 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 4.7074, 1.2773 which is equivalent to:
```
   RA(J2000)  = 00h 18m 49.79s
   Dec(J2000) = +01d 16' 38.1"
```
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 134 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. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 3.16 x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 127 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 none of the XRT error circle. 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 0.03.
Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti AT brera.inaf.it). 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 #21151
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 350 s of XRT Photon Counting mode data and 1 UVOT images for GRB 170526A, 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 = 4.70720, +1.27700 which is equivalent to:
```
RA (J2000): 00h 18m 49.73s
Dec (J2000): +01d 16' 37.2"
```
with an uncertainty of 2.1 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 #21154
A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Cholden-Brown (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and B. Sbarufatti report on behalf of the Swift-XRT team:
We have analysed 6.5 ks of XRT data for GRB 170526A (Sbarufatti et al. GCN Circ. 21149), from 132 s to 46.4 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 21151).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.87 (+0.14, -0.12).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.8 (+/-0.5). The best-fitting absorption column is 1.9 (+2.3, -1.6) x 10^21 cm^-2, consistent with the Galactic value of 3.2 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.9 (+2.3, -1.6) x 10^21 cm^-2
Galactic foreground: 3.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.8 (+/-0.5)
```
If the light curve continues to decay with a power-law decay index of 0.87, the count rate at T+24 hours will be 1.0 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.0 x 10^-14 (5.1 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00754549.
This circular is an official product of the Swift-XRT team.
GCN Circular #21155
S. R. Oates (Uni. of Warwick) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170526A 128 s after the BAT trigger (Sbarufatti et al., GCN Circ. 21149). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 21151) 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) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           128          278          147         >19.9
white              128         4127          344         >20.4
v                4338         4537          197         >18.5
b                 3722         5197          235         >19.7
u                  286         5152          404         >19.4
w1                4748         4947          196         >19.1
m2                4542         4742          197         >19.3
w2                4133         4333          197         >19.5
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #21156
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-327 to T+1275 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170526A (trigger #754549) (Sbarufatti et al., GCN Circ. 21149). The BAT ground-calculated position is RA, Dec = 4.723, 1.277 deg which is
```
  RA(J2000)  =  00h 18m 53.6s
  Dec(J2000) = +01d 16' 35.7"
```
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 94%.
The mask-weighted light curve shows a weak pulse structure that starts at ~T0, peaks at ~ T+1 s, and ends at ~ T+10 s. T90 (15-350 keV) is 7.9 +- 1.6 sec (estimated error including systematics).
The time-averaged spectrum from T+1.1 to T+10.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.25 +- 0.42. The fluence in the 15-150 keV band is 1.6 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.10 sec in the 15-150 keV band is 0.3 +- 0.2 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/754549/BA/
GCN Circular #21213
K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)
The AMI Large Array robotically triggered on the Swift alert for GRB 170526A (Sbarufatti et al., GCN 21149) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 May 27.16, May 30.29, May 31.33 and Jun 03.28 (UT) do not reveal any radio source at the XRT location (Goad et al., GCN 21151), with 3sigma upper limits of 312 uJy, 117 uJy, 96 uJy and 105 uJy respectively.
We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.

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Jochen Greiner, last update: 08-Jun-2017 [Disclaimer]