Gamma-ray Burst 240811A

(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:     Sun 11 Aug 24 14:07:46 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1248132,   Seg_Num: 0
GRB_RA:          226.373d {+15h 05m 30s} (J2000),
                 226.634d {+15h 06m 32s} (current),
                 225.844d {+15h 03m 23s} (1950)
GRB_DEC:         +28.854d {+28d 51' 15"} (J2000),
                 +28.760d {+28d 45' 36"} (current),
                 +29.047d {+29d 02' 50"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2706 [cnts]    Image_Peak=141 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       17591 [cnts]
BKG_TIME:        50838.02 SOD {14:07:18.02} UT
BKG_DUR:         8 [sec]
GRB_DATE:        20533 TJD;   224 DOY;   24/08/11
GRB_TIME:        50853.19 SOD {14:07:33.19} UT
GRB_PHI:         -23.30 [deg]
GRB_THETA:        32.95 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     8.88 [sigma]
IMAGE_SIGNIF:    7.37 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -3  +0  +0 -20  +0 
SUN_POSTN:       141.81d {+09h 27m 15s}  +15.00d {+15d 00' 08"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.43d {+14h 17m 44s}  -16.58d {-16d 34' 38"}
MOON_DIST:        46.85 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.45 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      212.82, 44.02 [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 = 61.62,20.61 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 11 Aug 24 14:09:42 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     1248132,   Seg_Num: 0
GRB_RA:          226.3653d {+15h 05m 27.6s} (J2000),
                 226.6259d {+15h 06m 30.2s} (current),
                 225.8359d {+15h 03m 20.6s} (1950)
GRB_DEC:         +28.8945d {+28d 53' 40.2"} (J2000),
                 +28.8002d {+28d 48' 00.6"} (current),
                 +29.0875d {+29d 05' 15.1"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       33 [cnts]
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50948.31 SOD {14:09:08.31} UT,   95.1 [sec] since BAT Trigger Time
CENTROID_X:      271.42,  raw= 271  [pixels]
CENTROID_Y:      244.45,  raw= 244  [pixels]
ROLL:            280.76 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -126.46
GRB_POS_XRT_Z:   -84.80
IMAGE_URL:       sw01248132000msxps_rw.img
SUN_POSTN:       141.81d {+09h 27m 16s}  +15.00d {+15d 00' 06"}
SUN_DIST:         78.39 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.45d {+14h 17m 47s}  -16.58d {-16d 35' 01"}
MOON_DIST:        46.89 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.30, 60.46 [deg] galactic lon,lat of the burst
ECL_COORDS:      212.79, 44.06 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 11 Aug 24 14:09:46 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1248132,   Seg_Num: 0
GRB_RA:          226.3653d {+15h 05m 27.6s} (J2000),
                 226.6259d {+15h 06m 30.2s} (current),
                 225.8359d {+15h 03m 20.6s} (1950)
GRB_DEC:         +28.8945d {+28d 53' 40.2"} (J2000),
                 +28.8002d {+28d 48' 00.6"} (current),
                 +29.0875d {+29d 05' 15.1"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       33 [cnts]
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50948.31 SOD {14:09:08.31} UT,   95.1 [sec] since BAT Trigger Time
CENTROID_X:      271.42,  raw= 271  [pixels]
CENTROID_Y:      244.45,  raw= 244  [pixels]
ROLL:            280.76 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -126.46
GRB_POS_XRT_Z:   -84.80
IMAGE_URL:       sw01248132000msxps_rw.img
SUN_POSTN:       141.81d {+09h 27m 16s}  +15.00d {+15d 00' 06"}
SUN_DIST:         78.39 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.45d {+14h 17m 48s}  -16.58d {-16d 35' 02"}
MOON_DIST:        46.89 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.30, 60.46 [deg] galactic lon,lat of the burst
ECL_COORDS:      212.79, 44.06 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 11 Aug 24 14:09:32 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1248132,   Seg_Num: 0
GRB_RA:          226.3653d {+15h 05m 27.67s} (J2000),
                 226.6259d {+15h 06m 30.21s} (current),
                 225.8359d {+15h 03m 20.62s} (1950)
GRB_DEC:         +28.8945d {+28d 53' 40.2"} (J2000),
                 +28.8002d {+28d 48' 00.6"} (current),
                 +29.0875d {+29d 05' 15.1"} (1950)
GRB_ERROR:       5.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       7.46e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.74 [sigma]
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50948.31 SOD {14:09:08.31} UT,   95.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.63 237.12 261.49 243.73
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       141.81d {+09h 27m 16s}  +15.00d {+15d 00' 06"}
SUN_DIST:         78.39 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.45d {+14h 17m 47s}  -16.58d {-16d 35' 00"}
MOON_DIST:        46.89 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.30, 60.46 [deg] galactic lon,lat of the burst
ECL_COORDS:      212.79, 44.06 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 2.44 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 11 Aug 24 14:11:26 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1248132,   Seg_Num: 0
GRB_RA:          226.373d {+15h 05m 30s} (J2000),
                 226.634d {+15h 06m 32s} (current),
                 225.844d {+15h 03m 23s} (1950)
GRB_DEC:         +28.854d {+28d 51' 15"} (J2000),
                 +28.760d {+28d 45' 36"} (current),
                 +29.047d {+29d 02' 50"} (1950)
GRB_DATE:        20533 TJD;   224 DOY;   24/08/11
GRB_TIME:        50853.19 SOD {14:07:33.19} UT
TRIGGER_INDEX:   146
GRB_PHI:         -23.30 [deg]
GRB_THETA:        32.95 [deg]
DELTA_TIME:      -76.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     8.88 [sigma]
IMAGE_SIGNIF:    7.37 [sigma]
LC_URL:          sw01248132000msb.lc
SUN_POSTN:       141.82d {+09h 27m 16s}  +15.00d {+15d 00' 05"}
SUN_DIST:         78.40 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.46d {+14h 17m 51s}  -16.59d {-16d 35' 22"}
MOON_DIST:        46.85 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.45 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      212.82, 44.02 [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 = 61.62,20.61 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 11 Aug 24 14:12:02 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.856d {+28d 51' 22"} (J2000)
POINT_ROLL:      280.765d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50955.60 SOD {14:09:15.60} UT,   102.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.020
N_STARS:         32
X_OFFSET:        528 [pixels]
Y_OFFSET:        512 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1471 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01248132000msufc0102.fits
SUN_POSTN:       141.82d {+09h 27m 16s}  +15.00d {+15d 00' 05"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.47d {+14h 17m 52s}  -16.59d {-16d 35' 29"}
MOON_DIST:        46.86 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 11 Aug 24 14:12:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.856d {+28d 51' 22"} (J2000)
POINT_ROLL:      280.765d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50955.60 SOD {14:09:15.60} UT,   102.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.020
N_STARS:         32
X_OFFSET:        528 [pixels]
Y_OFFSET:        512 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1471 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01248132000msufc0102.fits
SUN_POSTN:       141.82d {+09h 27m 16s}  +15.00d {+15d 00' 04"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.47d {+14h 17m 52s}  -16.59d {-16d 35' 33"}
MOON_DIST:        46.86 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [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:     Sun 11 Aug 24 14:13:21 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.856d {+28d 51' 22"} (J2000)
ROLL:            280.765d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50955.60 SOD {14:09:15.60} UT,   102.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     745078189
X_OFFSET:        1072 [pixels]
Y_OFFSET:        1020 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1232
Y_GRB_POS:       1180
BINNING_INDEX:   1
IM_URL:          sw01248132000msuni0136.fits
SUN_POSTN:       141.82d {+09h 27m 16s}  +15.00d {+15d 00' 04"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.48d {+14h 17m 54s}  -16.60d {-16d 35' 45"}
MOON_DIST:        46.86 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [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:     Sun 11 Aug 24 14:13:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.856d {+28d 51' 22"} (J2000)
ROLL:            280.765d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50955.60 SOD {14:09:15.60} UT,   102.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     745078189
X_OFFSET:        1072 [pixels]
Y_OFFSET:        1020 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1232
Y_GRB_POS:       1180
BINNING_INDEX:   1
IM_URL:          sw01248132000msuni0136.fits
SUN_POSTN:       141.82d {+09h 27m 16s}  +15.00d {+15d 00' 04"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.48d {+14h 17m 55s}  -16.60d {-16d 35' 47"}
MOON_DIST:        46.86 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [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:     Sun 11 Aug 24 14:20:44 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.855d {+28d 51' 17"} (J2000)
POINT_ROLL:      280.764d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  51167.80 SOD {14:12:47.80} UT,   314.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.454
N_STARS:         74
X_OFFSET:        752 [pixels]
Y_OFFSET:        700 [pixels]
X_MAX:           1711 [pixels]
Y_MAX:           1659 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw01248132000msufc0314.fits
SUN_POSTN:       141.82d {+09h 27m 17s}  +15.00d {+14d 59' 58"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.53d {+14h 18m 08s}  -16.62d {-16d 37' 13"}
MOON_DIST:        46.87 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 11 Aug 24 14:21:01 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.855d {+28d 51' 17"} (J2000)
POINT_ROLL:      280.764d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  51167.80 SOD {14:12:47.80} UT,   314.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.454
N_STARS:         74
X_OFFSET:        752 [pixels]
Y_OFFSET:        700 [pixels]
X_MAX:           1711 [pixels]
Y_MAX:           1659 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw01248132000msufc0314.fits
SUN_POSTN:       141.82d {+09h 27m 17s}  +15.00d {+14d 59' 58"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.54d {+14h 18m 09s}  -16.62d {-16d 37' 17"}
MOON_DIST:        46.87 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [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:     Sun 11 Aug 24 14:21:54 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.855d {+28d 51' 17"} (J2000)
ROLL:            280.764d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  51167.80 SOD {14:12:47.80} UT,   314.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     745078401
X_OFFSET:        1072 [pixels]
Y_OFFSET:        1020 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1232
Y_GRB_POS:       1180
BINNING_INDEX:   1
IM_URL:          sw01248132000msuni0348.fits
SUN_POSTN:       141.82d {+09h 27m 18s}  +15.00d {+14d 59' 57"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.54d {+14h 18m 11s}  -16.62d {-16d 37' 27"}
MOON_DIST:        46.87 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [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:     Sun 11 Aug 24 14:22:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1248132,   Seg_Num: 0
POINT_RA:        226.384d {+15h 05m 32s} (J2000)
POINT_DEC:       +28.855d {+28d 51' 17"} (J2000)
ROLL:            280.764d
IMG_START_DATE:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  51167.80 SOD {14:12:47.80} UT,   314.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     745078401
X_OFFSET:        1072 [pixels]
Y_OFFSET:        1020 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1232
Y_GRB_POS:       1180
BINNING_INDEX:   1
IM_URL:          sw01248132000msuni0348.fits
SUN_POSTN:       141.82d {+09h 27m 18s}  +15.00d {+14d 59' 57"}
SUN_DIST:         78.41 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.55d {+14h 18m 11s}  -16.63d {-16d 37' 30"}
MOON_DIST:        46.87 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.22, 60.44 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      212.83, 44.03 [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:     Sun 11 Aug 24 14:22:09 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1248132,   Seg_Num: 0
GRB_RA:          226.3621d {+15h 05m 26.90s} (J2000),
                 226.6227d {+15h 06m 29.44s} (current),
                 225.8327d {+15h 03m 19.85s} (1950)
GRB_DEC:         +28.8960d {+28d 53' 45.6"} (J2000),
                 +28.8017d {+28d 48' 06.0"} (current),
                 +29.0891d {+29d 05' 20.5"} (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:  20533 TJD;   224 DOY;   24/08/11
IMG_START_TIME:  50997.00 SOD {14:09:57.00} UT,   143.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       141.82d {+09h 27m 18s}  +15.00d {+14d 59' 57"}
SUN_DIST:         78.38 [deg]   Sun_angle= -5.7 [hr] (East of Sun)
MOON_POSTN:      214.55d {+14h 18m 11s}  -16.63d {-16d 37' 30"}
MOON_DIST:        46.90 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:       44.30, 60.47 [deg] galactic lon,lat of the burst
ECL_COORDS:      212.78, 44.06 [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 Circular #37136
K. L. Page (U Leicester) and R. Gupta (NASA GSFC) report on behalf of the Neil Gehrels Swift Observatory Team:
At 14:07:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 240811A (trigger=1248132). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 226.373, +28.854 which is
```
   RA(J2000) = 15h 05m 30s
   Dec(J2000) = +28d 51' 15"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 50 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~11 sec after the trigger.
The XRT began observing the field at 14:09:08.3 UT, 95.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 226.36218, 28.89573 which is equivalent to:
```
   RA(J2000)  = 15h 05m 26.92s
   Dec(J2000) = +28d 53' 44.6"
```
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 154 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 (1.98 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.5 (+3.65/-3.05) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 7.46e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 102 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.023.
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/)
GCN Circular #37137
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (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. Gress, N.M. Budnev, O.Ershova (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),
V. Yurkov, A. Gabovich (Blagoveschensk Educational State University)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 240811A ( K. L. Page et al., GCN 37136) errorbox 10112 sec after notice time and 10127 sec after trigger time at 2024-08-11 16:56:20 UT, with upper limit up to 16.7 mag. Observations started at twilight. The observations began at zenith distance = 61 deg. The sun altitude is -10.5 deg.
The galactic latitude b = 60 deg., longitude l = 44 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2558765
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   10218 |         MASTER-SAAO |   C |   180 | 16.7 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #37140
Guowang Du, Yuan Fang, Xufeng Zhu, Yehao Cheng, Yuze Zhao, Brajesh Kumar, Weikang Lin, Yuanpei Yang, Xinzhong Er, Xiangkun Liu and Xiaowei Liu (SWIFAR, YNU) report on behalf of Mephisto team:
We performed simultaneous multi-band photometric observations of GRB 240811A (Page & Gupta, GCN 37136) using 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. The observations were started ~37 min after the notice and multiple frames in uvgriz bands were acquired. The upper limits of our initial frames are the following:
```
UTC(2024-08-11)   Exptime(s)  filter   Mag(AB)
14:55               180          v     >21.07
14:55                60          r     >20.96
14:55               120          z     >19.98
15:08               180          u     >21.03
15:08                60          g     >20.97  
15:08               120          i     >20.86
```
----------------------------------------------------------------------------------
Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21.
----------------------------------------------------------------------------------
GCN Circular #37141
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1050 s of XRT Photon Counting mode data and 2 UVOT images for GRB 240811A, 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 = 226.36231, +28.89615 which is equivalent to:
```
RA (J2000): 15h 05m 26.96s
Dec (J2000): +28d 53' 46.1"
```
with an uncertainty of 2.4 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 #37142
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:
We observed the Swift GRB 240811A (Beardmore et al., GCN 37136) field with the LCOGT 1-meter Sinistro instrument at the Teide Observatory, Tenerife site, on August 11, from 20:43 to 21:13 UT (corresponding to 6.60 to 7.10 hours after the GRB trigger time) with the sdss r and i filters.
We performed a series of 3x300s exposures in each band. We do not detect an uncataloged source within the XRT error region in either band. This result is consistent with other optcal upper limits (Lipunov et al., GCN 37137; Du et al., GCN 37140).
The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference:
```
r > 22.6
i > 20.5
```
These magnitudes are not corrected for galactic extinction.
GCN Circular #37147
N. P. M. Kuin (UCL-MSSL) 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 240811A 102 s after the BAT trigger (Page et al., GCN Circ. 37136). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 37141) 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           102          252          147         >21.0
u_FC               315          564          246         >20.7
white              102         1191          353         >21.9
v                  644         5026          255         >18.7
b                  570         1167           58         >20.0
u                  315         1142          285         >20.7
w1                1098         5251           34         >19.2
m2                5031         5231          197         >18.8
w2                4622         4821          197         >19.6
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.023 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #37149
T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), J. D. Gropp (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.7 ks of XRT data for GRB 240811A, from 84 s to 39.6 ks after the BAT trigger. The data comprise 41 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode.
The light curve can be modelled with an initial power-law decay with an index of alpha=4.2 (+/-0.3), followed by a break at T+240 s to an alpha of 0.42 (+/-0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.97 (+0.19, -0.17). The best-fitting absorption column is 5.1 (+4.6, -3.1) x 10^20 cm^-2, consistent with the Galactic value of 2.0 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 3.4 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     5.1 (+4.6, -3.1) x 10^20 cm^-2
Galactic foreground: 2.0 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.97 (+0.19, -0.17)
```
If the light curve continues to decay with a power-law decay index of 0.42, the count rate at T+24 hours will be 0.036 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-12 (1.4 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/01248132.
This circular is an official product of the Swift-XRT team.
GCN Circular #37150
U.Quadri, L.Strabla and P.Madurini (Bassano Bresciano Astronomical Observatory - Italy),
Members of: AAVSO - American Association of Variable Star Observers. UAI/SSV - Unione Astrofili Italiani/SSV-GRB section. GAC - Gruppo Astrofili Cremonesi.
In a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), B. De Simone (Universita' degli Studi Di Salerno) report:
We imaged the field of GRB 240811A detected by SWIFT(trigger 1248132) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy. The observations started 5.56 hour after the GRB trigger, At the end of twilight with our Newton telescope D=450 mm F/D=4.5.
Weather conditions were good.
We co-added 150 exposures of 20 sec each (total 50 min).
```
Start T0+      End T0+      Vlim
5.56 hour     6.47 hour      21
```
We did not found any optical counterpart in the error box of the XRTcandidate (K. L. Page & R. Gupta, GCN 37136; v. Lipunov et al., GCN 37137; Guowang Du et al., GCN 37140; A.P. Beardmore et al., GCN 37141; R. Strausbaugh and A. Cucchiara, GCN 37142; N. P. M. Kuin and K. L. Page, GCN 37147; T. Sbarrato et al., GCN 37149).
Magnitudes were estimated with the pan-STARRS cat and are derived using Lupton (2005) equations.
Not corrected for galactic dust extinction.
Reference: http://www.osservatoriobassano.org/grb.asp
The message may be cited.
GCN Circular #37155
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240811A (trigger #1248132) (Page, et al., GCN Circ. 37136). The BAT ground-calculated position is RA, Dec = 226.328, 28.884 deg which is
```
   RA(J2000)  =  15h 05m 18.8s
   Dec(J2000) = +28d 53' 02.5"
```
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 71%.
The mask-weighted light curve shows a complex structure with many peaks and potential precursor emission ~30 seconds before the trigger time. T90 (15-350 keV) is 66.32 +- 5.22 sec (estimated error including systematics).
The time-averaged spectrum from T-42.95 to T+41.32 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.71 +- 0.08. The fluence in the 15-150 keV band is 3.0 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+11.30 sec in the 15-150 keV band is 2.9 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1248132
GCN Circular #37173
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The long-duration GRB 240811A (Swift detection: Page & Gupta, GCN 37136; Lien et al., GCN 37155) was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data in the 20-300 keV band reveals a >18 sigma count rate increase in the interval from T0-34.908 s to T0+35.748 s where T0 = T0(BAT) = 14:07:33.190 UT.
The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB240811A/
Modeling a time-integrated spectrum of the burst (from T0-34.908 s to T0+35.748 s) by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep): yields alpha = -1.22 (-0.27, + 0.80) and Ep = 126(-33,+51) keV.
The total burst fluence is 4.65(-0.30,+1.35)x10^-6 erg/cm^2, and the 2.944 s peak energy flux, measured from T0+3.364 s, is 2.43(-0.33,+0.76)x10^-7 erg/cm^2. (both in the 20 keV - 10 MeV energy range).
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.

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Jochen Greiner, last update: 13-Aug-2024 [Disclaimer]