Gamma-ray Burst 220518A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:19:47 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1107050,   Seg_Num: 0
GRB_RA:           55.369d {+03h 41m 29s} (J2000),
                  55.544d {+03h 42m 11s} (current),
                  54.980d {+03h 39m 55s} (1950)
GRB_DEC:         -47.571d {-47d 34' 15"} (J2000),
                 -47.500d {-47d 30' 00"} (current),
                 -47.730d {-47d 43' 47"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2475 [cnts]    Image_Peak=155 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   149     E_range: 25-100 keV
BKG_INTEN:       15283 [cnts]
BKG_TIME:        22746.84 SOD {06:19:06.84} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19717 TJD;   138 DOY;   22/05/18
GRB_TIME:        22760.85 SOD {06:19:20.85} UT
GRB_PHI:          -4.66 [deg]
GRB_THETA:        41.24 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.83 [sigma]
IMAGE_SIGNIF:    9.46 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +0  +0  +0 -38  +0 
SUN_POSTN:        55.03d {+03h 40m 08s}  +19.56d {+19d 33' 23"}
SUN_DIST:         67.06 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.07d {+17h 44m 16s}  -26.25d {-26d 14' 46"}
MOON_DIST:       101.30 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.27,-51.19 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       29.37,-63.90 [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 = 19.58,-3.23 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:21:35 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 22"} (J2000)
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  22887.16 SOD {06:21:27.16} UT,   126.3 [sec] since BAT Trigger Time
COUNTS:          2    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    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:     Wed 18 May 22 06:24:15 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 22"} (J2000)
POINT_ROLL:      359.687d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  22890.32 SOD {06:21:30.32} UT,   129.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.396
N_STARS:         19
X_OFFSET:        387 [pixels]
Y_OFFSET:        621 [pixels]
X_MAX:           1346 [pixels]
Y_MAX:           1580 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw01107050000msufc0129.fits
SUN_POSTN:        55.03d {+03h 40m 08s}  +19.56d {+19d 33' 25"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.12d {+17h 44m 29s}  -26.25d {-26d 15' 03"}
MOON_DIST:       101.29 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:24:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 22"} (J2000)
POINT_ROLL:      359.687d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  22890.32 SOD {06:21:30.32} UT,   129.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.396
N_STARS:         19
X_OFFSET:        387 [pixels]
Y_OFFSET:        621 [pixels]
X_MAX:           1346 [pixels]
Y_MAX:           1580 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw01107050000msufc0129.fits
SUN_POSTN:        55.04d {+03h 40m 08s}  +19.56d {+19d 33' 25"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.12d {+17h 44m 29s}  -26.25d {-26d 15' 04"}
MOON_DIST:       101.29 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:25:57 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 22"} (J2000)
ROLL:            359.687d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  22890.32 SOD {06:21:30.32} UT,   129.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     674547719
X_OFFSET:        706 [pixels]
Y_OFFSET:        940 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       866
Y_GRB_POS:       1100
BINNING_INDEX:   1
IM_URL:          sw01107050000msuni0159.fits
SUN_POSTN:        55.04d {+03h 40m 09s}  +19.56d {+19d 33' 26"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.14d {+17h 44m 33s}  -26.25d {-26d 15' 10"}
MOON_DIST:       101.28 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:25:04 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1107050,   Seg_Num: 0
GRB_RA:           55.3422d {+03h 41m 22.12s} (J2000),
                  55.5168d {+03h 42m 04.02s} (current),
                  54.9524d {+03h 39m 48.58s} (1950)
GRB_DEC:         -47.5837d {-47d 35' 01.3"} (J2000),
                 -47.5130d {-47d 30' 46.8"} (current),
                 -47.7428d {-47d 44' 34.0"} (1950)
GRB_ERROR:       3.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  22894.00 SOD {06:21:34.00} UT,   133.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        55.04d {+03h 40m 08s}  +19.56d {+19d 33' 26"}
SUN_DIST:         67.07 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.13d {+17h 44m 31s}  -26.25d {-26d 15' 06"}
MOON_DIST:       101.25 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.29,-51.20 [deg] galactic lon,lat of the burst
ECL_COORDS:       29.31,-63.90 [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 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:26:11 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 22"} (J2000)
ROLL:            359.687d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  22890.32 SOD {06:21:30.32} UT,   129.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     674547719
X_OFFSET:        706 [pixels]
Y_OFFSET:        940 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       866
Y_GRB_POS:       1100
BINNING_INDEX:   1
IM_URL:          sw01107050000msuni0159.fits
SUN_POSTN:        55.04d {+03h 40m 09s}  +19.56d {+19d 33' 26"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.14d {+17h 44m 34s}  -26.25d {-26d 15' 11"}
MOON_DIST:       101.28 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [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:     Wed 18 May 22 06:32:38 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.366d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 19"} (J2000)
POINT_ROLL:      359.688d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23102.24 SOD {06:25:02.24} UT,   341.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.942
N_STARS:         31
X_OFFSET:        147 [pixels]
Y_OFFSET:        381 [pixels]
X_MAX:           1586 [pixels]
Y_MAX:           1820 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw01107050000msufc0341.fits
SUN_POSTN:        55.04d {+03h 40m 10s}  +19.56d {+19d 33' 30"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.22d {+17h 44m 52s}  -26.26d {-26d 15' 35"}
MOON_DIST:       101.25 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:32:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.366d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 19"} (J2000)
POINT_ROLL:      359.688d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23102.24 SOD {06:25:02.24} UT,   341.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.942
N_STARS:         31
X_OFFSET:        147 [pixels]
Y_OFFSET:        381 [pixels]
X_MAX:           1586 [pixels]
Y_MAX:           1820 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw01107050000msufc0341.fits
SUN_POSTN:        55.04d {+03h 40m 10s}  +19.56d {+19d 33' 30"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.22d {+17h 44m 52s}  -26.26d {-26d 15' 36"}
MOON_DIST:       101.25 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:34:00 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.366d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 19"} (J2000)
ROLL:            359.688d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23102.24 SOD {06:25:02.24} UT,   341.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     674547931
X_OFFSET:        706 [pixels]
Y_OFFSET:        940 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       866
Y_GRB_POS:       1100
BINNING_INDEX:   1
IM_URL:          sw01107050000msuni0371.fits
SUN_POSTN:        55.04d {+03h 40m 10s}  +19.56d {+19d 33' 31"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.23d {+17h 44m 55s}  -26.26d {-26d 15' 40"}
MOON_DIST:       101.25 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:32:58 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1107050,   Seg_Num: 0
GRB_RA:           55.3430d {+03h 41m 22.32s} (J2000),
                  55.5176d {+03h 42m 04.21s} (current),
                  54.9532d {+03h 39m 48.77s} (1950)
GRB_DEC:         -47.5839d {-47d 35' 02.0"} (J2000),
                 -47.5132d {-47d 30' 47.5"} (current),
                 -47.7430d {-47d 44' 34.7"} (1950)
GRB_ERROR:       1.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  22894.00 SOD {06:21:34.00} UT,   133.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        55.04d {+03h 40m 10s}  +19.56d {+19d 33' 30"}
SUN_DIST:         67.07 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.22d {+17h 44m 53s}  -26.26d {-26d 15' 37"}
MOON_DIST:       101.22 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.29,-51.20 [deg] galactic lon,lat of the burst
ECL_COORDS:       29.32,-63.90 [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 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:34:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.366d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 19"} (J2000)
ROLL:            359.688d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23102.24 SOD {06:25:02.24} UT,   341.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     674547931
X_OFFSET:        706 [pixels]
Y_OFFSET:        940 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       866
Y_GRB_POS:       1100
BINNING_INDEX:   1
IM_URL:          sw01107050000msuni0371.fits
SUN_POSTN:        55.04d {+03h 40m 10s}  +19.56d {+19d 33' 31"}
SUN_DIST:         67.04 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.23d {+17h 44m 56s}  -26.26d {-26d 15' 41"}
MOON_DIST:       101.24 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [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:     Wed 18 May 22 06:38:57 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 20"} (J2000)
POINT_ROLL:      359.689d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23634.12 SOD {06:33:54.12} UT,   873.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.818
N_STARS:         85
X_OFFSET:        147 [pixels]
Y_OFFSET:        381 [pixels]
X_MAX:           1586 [pixels]
Y_MAX:           1820 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01107050000msufc0873.fits
SUN_POSTN:        55.04d {+03h 40m 11s}  +19.56d {+19d 33' 33"}
SUN_DIST:         67.05 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.29d {+17h 45m 09s}  -26.27d {-26d 16' 00"}
MOON_DIST:       101.22 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:40:16 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 20"} (J2000)
ROLL:            359.689d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23634.12 SOD {06:33:54.12} UT,   873.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     674548463
X_OFFSET:        706 [pixels]
Y_OFFSET:        940 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       866
Y_GRB_POS:       1100
BINNING_INDEX:   1
IM_URL:          sw01107050000msuni0903.fits
SUN_POSTN:        55.05d {+03h 40m 11s}  +19.56d {+19d 33' 34"}
SUN_DIST:         67.05 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.30d {+17h 45m 13s}  -26.27d {-26d 16' 04"}
MOON_DIST:       101.22 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:39:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 20"} (J2000)
POINT_ROLL:      359.689d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23634.12 SOD {06:33:54.12} UT,   873.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.818
N_STARS:         85
X_OFFSET:        147 [pixels]
Y_OFFSET:        381 [pixels]
X_MAX:           1586 [pixels]
Y_MAX:           1820 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01107050000msufc0873.fits
SUN_POSTN:        55.05d {+03h 40m 11s}  +19.56d {+19d 33' 33"}
SUN_DIST:         67.05 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.29d {+17h 45m 10s}  -26.27d {-26d 16' 00"}
MOON_DIST:       101.22 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 18 May 22 06:40:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1107050,   Seg_Num: 0
POINT_RA:         55.367d {+03h 41m 28s} (J2000)
POINT_DEC:       -47.556d {-47d 33' 20"} (J2000)
ROLL:            359.689d
IMG_START_DATE:  19717 TJD;   138 DOY;   22/05/18
IMG_START_TIME:  23634.12 SOD {06:33:54.12} UT,   873.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     674548463
X_OFFSET:        706 [pixels]
Y_OFFSET:        940 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       866
Y_GRB_POS:       1100
BINNING_INDEX:   1
IM_URL:          sw01107050000msuni0903.fits
SUN_POSTN:        55.05d {+03h 40m 11s}  +19.56d {+19d 33' 34"}
SUN_DIST:         67.05 [deg]   Sun_angle= -0.0 [hr] (East of Sun)
MOON_POSTN:      266.31d {+17h 45m 13s}  -26.27d {-26d 16' 05"}
MOON_DIST:       101.21 [deg]
MOON_ILLUM:      94 [%]
GAL_COORDS:      256.24,-51.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       29.38,-63.89 [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 #32060
J.D. Gropp (PSU), K. L. Page (U Leicester), T. M. Parsotan (GSFC/UMBC/CRESSTII), B. Sbarufatti (PSU) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 06:19:20 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 220518A (trigger= 1107050). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 55.369, -47.571 which is
```
   RA(J2000) = +03h 41m 29s
   Dec(J2000) = -47d 34' 15"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). There are currently no BAT light curve data available at this time.
The XRT began observing the field at 06:21:27.1 UT, 126.4 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 55.34297, -47.58392 which is equivalent to:
```
   RA(J2000)  = 03h 41m 22.31s
   Dec(J2000) = -47d 35' 02.1"
```
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 78 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 https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (9.33 x 10^19 cm^-2, Willingale et al. 2013), with an excess column of 5 (+3.25/-2.72) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 129 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 0.008.
Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 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/)
GCN Circular #32061
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 220518A ( J.D. Gropp et al., GCN 32060) errorbox 6501 sec after notice time and 6534 sec after trigger time at 2022-05-18 08:08:15 UT, with upper limit up to 15.6 mag. The observations began at zenith distance = 87 deg. The sun altitude is -40.1 deg.
The galactic latitude b = -51 deg., longitude l = 256 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1977169
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

    6565 |         MASTER-OAFA |   C |    60 | 14.3 |        
    7687 |         MASTER-OAFA |   C |   180 | 15.3 |        
    7947 |         MASTER-OAFA |   C |    60 | 15.6 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #32062
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1717 s of XRT Photon Counting mode data and 2 UVOT images for GRB 220518A, 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 = 55.34331, -47.58376 which is equivalent to:
```
RA (J2000): 03h 41m 22.39s
Dec (J2000): -47d 35' 01.5"
```
with an uncertainty of 2.2 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 #32063
S. R. Oates (U.Birmingham) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220518A 129 s after the BAT trigger (Gropp et al., GCN Circ. 32060). A source consistent with the enhanced XRT position (Beardmore et al. GCN Circ. 32062) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
   RA  (J2000) =  03:41:22.29 =  55.34289 (deg.)
   Dec (J2000) = -47:35:00.3  = -47.58342 (deg.)
```
with an estimated uncertainty of 0.55 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag
white (FC)        129          279         147         20.00 +/- 0.25
white             621         1717         334         20.49 +/- 0.23
v                 671         1767         136         >19.0
b                 597         1861         131         >20.1
u (FC)            341          591         246         >19.7
u                 341         1841         324         >19.9
w1               1103         1296          39         >18.4
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.008 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #32067
J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB) and J.D. Gropp report on behalf of the Swift-XRT team:
We have analysed 6.5 ks of XRT data for GRB 220518A (Gropp et al. GCN Circ. 32060), from 133 s to 53.3 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. 32062).
The late-time light curve (from T0+7.3 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 1.85 (+0.15, -0.14). The best-fitting absorption column is 2.7 (+3.1, -1.8) x 10^20 cm^-2, consistent with the Galactic value of 9.3 x 10^19 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (3.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.7 (+3.1, -1.8) x 10^20 cm^-2
Galactic foreground: 9.3 x 10^19 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.85 (+0.15, -0.14)
```
If the light curve continues to decay with a power-law decay index of 1.3, the count rate at T+24 hours will be 3.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-13 (1.3 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01107050.
This circular is an official product of the Swift-XRT team.
GCN Circular #32069
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU), (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220518A (trigger #1107050) (Gropp et al., GCN 32060). The BAT ground-calculated position is RA, Dec = 55.340, -47.593 deg which is
```
   RA(J2000)  =  03h 41m 21.6s 
   Dec(J2000) = -47d 35' 36.3" 
```
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 51%.
The light curve has a peak at the trigger time and potential precursor emission occuring slightly before the BAT trigger time. T90 (15-350 keV) is 12.29 +- 3.07 sec (estimated error including systematics). The time-averaged spectrum from T-8.36 to T+7.58 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.71 +- 0.21. The fluence in the 15-150 keV band is 5.7 +- 0.8 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+0.07 sec in the 15-150 keV band is 1.8 +- 0.3 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/1107050/BA/

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Jochen Greiner, last update: 20-May-2022 [Disclaimer]