Gamma-ray Burst 180809B

(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:     Thu 09 Aug 18 20:30:33 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     852553,   Seg_Num: 0
GRB_RA:          299.6998d {+19h 58m 47.9s} (J2000),
                 299.9627d {+19h 59m 51.0s} (current),
                 298.9926d {+19h 55m 58.2s} (1950)
GRB_DEC:         -15.2988d {-15d 17' 55.6"} (J2000),
                 -15.2473d {-15d 14' 50.1"} (current),
                 -15.4352d {-15d 26' 06.8"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       25 [cnts]
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73798.59 SOD {20:29:58.59} UT
CENTROID_X:      311.49,  raw= 311  [pixels]
CENTROID_Y:      295.87,  raw= 296  [pixels]
ROLL:            273.79 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -5.95
GRB_POS_XRT_Z:   12.00
IMAGE_URL:       sw00852553000msxps_rw.img
SUN_POSTN:       139.65d {+09h 18m 37s}  +15.68d {+15d 40' 38"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.81d {+07h 47m 14s}  +20.24d {+20d 14' 33"}
MOON_DIST:       174.17 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.30,-21.65 [deg] galactic lon,lat of the burst
ECL_COORDS:      298.68,  5.23 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

red DSS finding chart ps-file

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Thu 09 Aug 18 20:29:57 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    8120,   Sub_Num: 0
GRB_INTEN:      9.30 [sigma]   
GRB_TIME:       73724.54 SOD {20:28:44.54} UT
GRB_DATE:       18339 TJD;   221 DOY;   18/08/09
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=0.2000 and Time_Error=0.1000.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(3.0<100sec) coincident
+with the CALET_GBM event (trignum=1217881726).
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at: 
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2018-08/2018-08-09T20-28-44.5042-05986-43920-0.lc

GCN NOTICE

 
TITLE:           GCN/CALET NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:29:15 UT
NOTICE_TYPE:     CALET GBM Flight Lightcurve
POINT_RA:        232.38d {+15h 29m 32s} (J2000),
POINT_DEC:       +47.24d {+47d 14' 16"} (J2000),
TRIGGER_NUM:     1217881726    
TRIGGER_DATE:    18339 TJD;   221 DOY;   18/08/09
TRIGGER_TIME:    73721.47 SOD {20:28:41.47} UT
TRIGGER_DET:     0 0 1 (HXM1 HXM2 SGM)
SIGNIFICANCE:    16.89 [sigma] 
FOREGND_DUR:     4.00 [sec]
BACKGND_DUR1:    16.00 [sec]   
ENERGY_BAND:     40-230 [keV]  
SC_LON_LAT:      327.02,47.18 [deg]
LC_URL:          http://cgbm.calet.jp/cgbm_trigger/flight//1217881726/index.html
COMMENTS:        CALET-GBM Flight Lightcurve.
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:30:23 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     852553,   Seg_Num: 0
GRB_RA:          299.6998d {+19h 58m 47.95s} (J2000),
                 299.9627d {+19h 59m 51.05s} (current),
                 298.9926d {+19h 55m 58.22s} (1950)
GRB_DEC:         -15.2988d {-15d 17' 55.6"} (J2000),
                 -15.2473d {-15d 14' 50.1"} (current),
                 -15.4352d {-15d 26' 06.8"} (1950)
GRB_ERROR:       6.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.51e-08 [erg/cm2/sec]
GRB_SIGNIF:      5.00 [sigma]
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73798.59 SOD {20:29:58.59} UT
TAM[0-3]:        327.65 237.17 261.72 243.58
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       139.65d {+09h 18m 37s}  +15.68d {+15d 40' 38"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.81d {+07h 47m 13s}  +20.24d {+20d 14' 33"}
MOON_DIST:       174.17 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.30,-21.65 [deg] galactic lon,lat of the burst
ECL_COORDS:      298.68,  5.23 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:           
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!  
COMMENTS:

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:30:35 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     852553,   Seg_Num: 0
GRB_RA:          299.6998d {+19h 58m 47.9s} (J2000),
                 299.9627d {+19h 59m 51.0s} (current),
                 298.9926d {+19h 55m 58.2s} (1950)
GRB_DEC:         -15.2988d {-15d 17' 55.6"} (J2000),
                 -15.2473d {-15d 14' 50.1"} (current),
                 -15.4352d {-15d 26' 06.8"} (1950)
GRB_ERROR:       6.1 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       25 [cnts]
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73798.59 SOD {20:29:58.59} UT
CENTROID_X:      311.49,  raw= 311  [pixels]
CENTROID_Y:      295.87,  raw= 296  [pixels]
ROLL:            273.79 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -5.95
GRB_POS_XRT_Z:   12.00
IMAGE_URL:       sw00852553000msxps_rw.img
SUN_POSTN:       139.65d {+09h 18m 37s}  +15.68d {+15d 40' 38"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.81d {+07h 47m 14s}  +20.24d {+20d 14' 33"}
MOON_DIST:       174.17 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.30,-21.65 [deg] galactic lon,lat of the burst
ECL_COORDS:      298.68,  5.23 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:32:20 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     852553,   Seg_Num: 0
GRB_RA:          299.712d {+19h 58m 51s} (J2000),
                 299.975d {+19h 59m 54s} (current),
                 299.005d {+19h 56m 01s} (1950)
GRB_DEC:         -15.302d {-15d 18' 06"} (J2000),
                 -15.250d {-15d 15' 01"} (current),
                 -15.438d {-15d 26' 18"} (1950)
GRB_DATE:        18339 TJD;   221 DOY;   18/08/09
GRB_TIME:        73728.10 SOD {20:28:48.10} UT
TRIGGER_INDEX:   146
GRB_PHI:         100.30 [deg]
GRB_THETA:        21.68 [deg]
DELTA_TIME:      -70.00 [sec]
TRIGGER_DUR:      [sec],  copy from BAT_POS unavailable
SOLN_STATUS:     0x0
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    0.00 [sigma]
LC_URL:          sw00852553000msb.lc
SUN_POSTN:       139.65d {+09h 18m 37s}  +15.68d {+15d 40' 37"}
SUN_DIST:        161.04 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.83d {+07h 47m 18s}  +20.24d {+20d 14' 26"}
MOON_DIST:       174.18 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.30,-21.67 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      298.69,  5.23 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!  
COMMENTS:           
COMMENTS:        This does not match any source in the ground catalog.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:33:02 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.698d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
POINT_ROLL:      273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73809.83 SOD {20:30:09.83} UT
FILTER:          10, White
BKG_MEAN:        3.008
N_STARS:         140
X_OFFSET:        461 [pixels]
Y_OFFSET:        577 [pixels]
X_MAX:           1420 [pixels]
Y_MAX:           1536 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00852553000msufc555539409.fits
SUN_POSTN:       139.65d {+09h 18m 37s}  +15.68d {+15d 40' 37"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.83d {+07h 47m 20s}  +20.24d {+20d 14' 24"}
MOON_DIST:       174.19 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:33:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.698d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
POINT_ROLL:      273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73809.83 SOD {20:30:09.83} UT
FILTER:          10, White
BKG_MEAN:        3.008
N_STARS:         140
X_OFFSET:        461 [pixels]
Y_OFFSET:        577 [pixels]
X_MAX:           1420 [pixels]
Y_MAX:           1536 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00852553000msufc555539409.fits
SUN_POSTN:       139.65d {+09h 18m 37s}  +15.68d {+15d 40' 36"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.84d {+07h 47m 21s}  +20.24d {+20d 14' 23"}
MOON_DIST:       174.19 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [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:     Thu 09 Aug 18 20:34:28 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.698d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
ROLL:            273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73809.83 SOD {20:30:09.83} UT
FILTER:          10, White
EXPOSURE_ID:     555539431
X_OFFSET:        781 [pixels]
Y_OFFSET:        897 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       941
Y_GRB_POS:       1057
BINNING_INDEX:   1
IM_URL:          sw00852553000msuni555539431.fits
SUN_POSTN:       139.66d {+09h 18m 37s}  +15.68d {+15d 40' 35"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.85d {+07h 47m 24s}  +20.24d {+20d 14' 19"}
MOON_DIST:       174.20 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [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:     Thu 09 Aug 18 20:34:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.698d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
ROLL:            273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73809.83 SOD {20:30:09.83} UT
FILTER:          10, White
EXPOSURE_ID:     555539431
X_OFFSET:        781 [pixels]
Y_OFFSET:        897 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       941
Y_GRB_POS:       1057
BINNING_INDEX:   1
IM_URL:          sw00852553000msuni555539431.fits
SUN_POSTN:       139.66d {+09h 18m 37s}  +15.68d {+15d 40' 35"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.85d {+07h 47m 25s}  +20.24d {+20d 14' 18"}
MOON_DIST:       174.20 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [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:     Thu 09 Aug 18 20:35:22 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     852553,   Seg_Num: 0
GRB_RA:          299.6998d {+19h 58m 47.95s} (J2000),
                 299.9627d {+19h 59m 51.05s} (current),
                 298.9926d {+19h 55m 58.22s} (1950)
GRB_DEC:         -15.2991d {-15d 17' 56.7"} (J2000),
                 -15.2476d {-15d 14' 51.2"} (current),
                 -15.4355d {-15d 26' 07.9"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         18.90 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  73806.00 SOD {20:30:06.00} UT
SUN_POSTN:       139.66d {+09h 18m 37s}  +15.68d {+15d 40' 35"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.86d {+07h 47m 27s}  +20.24d {+20d 14' 16"}
MOON_DIST:       174.20 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.30,-21.65 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      298.68,  5.23 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 0.7 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:39:40 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
POINT_ROLL:      273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74021.80 SOD {20:33:41.80} UT
FILTER:          7, U
BKG_MEAN:        0.796
N_STARS:         78
X_OFFSET:        461 [pixels]
Y_OFFSET:        577 [pixels]
X_MAX:           1420 [pixels]
Y_MAX:           1536 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00852553000msufc555539621.fits
SUN_POSTN:       139.66d {+09h 18m 38s}  +15.68d {+15d 40' 32"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.91d {+07h 47m 38s}  +20.23d {+20d 14' 01"}
MOON_DIST:       174.23 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.67,  5.23 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:39:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
POINT_ROLL:      273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74021.80 SOD {20:33:41.80} UT
FILTER:          7, U
BKG_MEAN:        0.796
N_STARS:         78
X_OFFSET:        461 [pixels]
Y_OFFSET:        577 [pixels]
X_MAX:           1420 [pixels]
Y_MAX:           1536 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00852553000msufc555539621.fits
SUN_POSTN:       139.66d {+09h 18m 38s}  +15.68d {+15d 40' 31"}
SUN_DIST:        161.02 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.91d {+07h 47m 39s}  +20.23d {+20d 13' 60"}
MOON_DIST:       174.23 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.67,  5.23 [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:     Thu 09 Aug 18 20:41:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
ROLL:            273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74021.80 SOD {20:33:41.80} UT
FILTER:          7, U
EXPOSURE_ID:     555539643
X_OFFSET:        781 [pixels]
Y_OFFSET:        897 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       941
Y_GRB_POS:       1057
BINNING_INDEX:   1
IM_URL:          sw00852553000msuni555539643.fits
SUN_POSTN:       139.66d {+09h 18m 38s}  +15.68d {+15d 40' 31"}
SUN_DIST:        161.01 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.92d {+07h 47m 42s}  +20.23d {+20d 13' 56"}
MOON_DIST:       174.24 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.67,  5.23 [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:     Thu 09 Aug 18 20:41:17 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
ROLL:            273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74021.80 SOD {20:33:41.80} UT
FILTER:          7, U
EXPOSURE_ID:     555539643
X_OFFSET:        781 [pixels]
Y_OFFSET:        897 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       941
Y_GRB_POS:       1057
BINNING_INDEX:   1
IM_URL:          sw00852553000msuni555539643.fits
SUN_POSTN:       139.66d {+09h 18m 38s}  +15.68d {+15d 40' 31"}
SUN_DIST:        161.01 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.93d {+07h 47m 42s}  +20.23d {+20d 13' 55"}
MOON_DIST:       174.24 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.67,  5.23 [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:     Thu 09 Aug 18 20:46:11 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
POINT_ROLL:      273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74599.32 SOD {20:43:19.32} UT
FILTER:          10, White
BKG_MEAN:        2.870
N_STARS:         190
X_OFFSET:        221 [pixels]
Y_OFFSET:        337 [pixels]
X_MAX:           1660 [pixels]
Y_MAX:           1776 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00852553000msufc555540199.fits
SUN_POSTN:       139.66d {+09h 18m 39s}  +15.67d {+15d 40' 27"}
SUN_DIST:        161.01 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.98d {+07h 47m 55s}  +20.23d {+20d 13' 38"}
MOON_DIST:       174.27 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN Circular #23105
M. J. Moss (George Washington University), S. D. Barthelmy (GSFC), V. D'Elia (ASDC), C. Gronwall (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 20:28:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180809B (trigger=852553). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 299.712, -15.302, which is
```
   RA(J2000)  =  19h 58m 51s
   Dec(J2000) = -15d 18' 06"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple bright peaks structure with a total duration of about 80 sec. The peak count rate was ~35,000 counts/sec (15-350 keV), at ~35 sec after the trigger.
XRT found a bright, uncatalogued X-ray source located at RA, Dec 299.6998, -15.2988 which is equivalent to:
```
   RA(J2000)  = +19h 58m 47.95s
   Dec(J2000) = -15d 17' 55.7" 
```
with an uncertainty of 6.1 arcseconds (radius, 90% containment). No event data are yet available to determine the column density using X-ray spectroscopy.
The initial flux in the 0.1 s image was 1.51e-08 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 81 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =  19:58:47.96 = 299.69983
  DEC(J2000) = -15:17:56.9  = -15.29915
```
with a 90%-confidence error radius of about 0.64 arc sec. This position is 1.3 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.91 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.16.
Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 09 Aug 18 20:46:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
POINT_ROLL:      273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74599.32 SOD {20:43:19.32} UT
FILTER:          10, White
BKG_MEAN:        2.870
N_STARS:         190
X_OFFSET:        221 [pixels]
Y_OFFSET:        337 [pixels]
X_MAX:           1660 [pixels]
Y_MAX:           1776 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00852553000msufc555540199.fits
SUN_POSTN:       139.66d {+09h 18m 39s}  +15.67d {+15d 40' 27"}
SUN_DIST:        161.01 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      116.99d {+07h 47m 57s}  +20.23d {+20d 13' 36"}
MOON_DIST:       174.27 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [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:     Thu 09 Aug 18 20:47:37 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
ROLL:            273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74599.32 SOD {20:43:19.32} UT
FILTER:          10, White
EXPOSURE_ID:     555540220
X_OFFSET:        780 [pixels]
Y_OFFSET:        896 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       940
Y_GRB_POS:       1056
BINNING_INDEX:   1
IM_URL:          sw00852553000msuni555540221.fits
SUN_POSTN:       139.66d {+09h 18m 39s}  +15.67d {+15d 40' 26"}
SUN_DIST:        161.01 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      117.00d {+07h 47m 59s}  +20.23d {+20d 13' 33"}
MOON_DIST:       174.28 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [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:     Thu 09 Aug 18 20:47:52 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     852553,   Seg_Num: 0
POINT_RA:        299.696d {+19h 58m 47s} (J2000)
POINT_DEC:       -15.300d {-15d 18' 00"} (J2000)
ROLL:            273.792d
IMG_START_DATE:  18339 TJD;   221 DOY;   18/08/09
IMG_START_TIME:  74599.32 SOD {20:43:19.32} UT
FILTER:          10, White
EXPOSURE_ID:     555540220
X_OFFSET:        780 [pixels]
Y_OFFSET:        896 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       940
Y_GRB_POS:       1056
BINNING_INDEX:   1
IM_URL:          sw00852553000msuni555540221.fits
SUN_POSTN:       139.66d {+09h 18m 39s}  +15.67d {+15d 40' 26"}
SUN_DIST:        161.01 [deg]   Sun_angle= -10.7 [hr] (East of Sun)
MOON_POSTN:      117.00d {+07h 48m 00s}  +20.23d {+20d 13' 32"}
MOON_DIST:       174.28 [deg]
MOON_ILLUM:      4 [%]
GAL_COORDS:       26.29,-21.65 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      298.68,  5.23 [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 #23109
V. Lipunov, N.Tiurina, E. Gorbovskoy, V.Kornilov, A.Kuznetsov, V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, D. Vlasenko Lomonosov Moscow State University,SAI
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias (IAC)
D. Buckley, South African Astronomical Observatory (SAAO)
A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA)
H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University (ISU)
A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University (BSPU)
MASTER-SAAO robotic telescope (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 GRB180809B(Moss et al. GCN 23105) 16 sec after notice time and 42 sec after trigger time at 2018-08-09 20:30:40 UT. On our 3-th (20s exposure) set , obtained 101 sec after tigger time at 2018-08-09 20:31:39 UT, we found 1 optical transient within SWIFT error-box
```
  T-Tmid      Date      Time       Expt.        Ra                Dec           mag
---------|---------------------|-------|-----------------|-----------------|-------
      111   2018-08-09 20:31:39      20    (19h 58m 48.0s , -15d 17m 57.1s)     16.87
```
also detected by Swift UVOT (Moss et al. GCN 23105)
The 5-sigma upper limit has been about 17.4mag The message may be cited.
GCN Circular #23110
Alan M. Watson (UNAM), Eleonora Troja (GSFC), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes�s Gonz�lez (UNAM), Carlos Rom�n-Z��iga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:
We observed the field of GRB 180809B (Moss et al., GCN Circ. 23105) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron�mico Nacional on Sierra San Pedro M�rtir from 2018/08 10.19 to 2018/08 10.29 UTC (8.2 to 10.6 hours after the BAT trigger), obtaining a total of 1.42 hours exposure in the r and i bands.
We do not detect the UVOT and MASTER optical counterpart (Moss et al., GCN Circ. 23105; Lipunov et al., GCN Circ. 23109) to the following 3-sigma limits:
```
r > 23.6
i > 23.5
```
These magnitudes are in comparison with the USNO-B1, are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
The optical counterpart has faded by more than 6 magnitudes between the MASTER and RATIR observations.
We thank the staff of the Observatorio Astron�mico Nacional in San Pedro M�rtir.
GCN Circular #23111
Tassilo Schweyer (MPE Garching) and Patricia Schady (University of Bath) report:
We observed the field of GRB 180809B (Swift trigger 852553; Moss et al., GCN #23105) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile).
Observations started at 23:00UT on 2018-08-09, 2.5 hrs after the GRB trigger. They were performed at an average seeing of 1.3" and at an average airmass of 2.
We detect a source in the JHK bands consistent with the position of the X-ray and optical afterglow (Mass et al., GCN #23105; Lipunov et al., GCN #23109). Based on a total exposure of time of 19 minutes in g'r'i'z' and 29 minutes in JHK we estimate the following AB magnitudes and upper limits at the position of the UVOT detection:
```
g' > 23.9 mag
r' > 23.9 mag
i' > 22.9 mag
z' > 22.4 mag
J = 21.0 +/- 0.3 mag
H = 19.9 +/- 0.2 mag
K = 18.7 +/- 0.1 mag
```
Given magnitudes are calibrated against PanSTARRS and 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.14 in the direction of the burst (Schlafly & Finkbeiner 2011).
We thank Markus Rabus for the excellent support from La Silla.
GCN Circular #23112
C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:
We observed Swift GRB 180809B (Moss et al. GCN 23105) with the LCO 1-m units at Sutherland Observatory (South Africa) on August 09, from 20:58 to 22:29 UT (corresponding to 0.5 to 2.0 hours from the GRB trigger time) with the SDSS r' and i' filters. We clearly detect the optical afterglow (Moss et al; Lipunov et al. GCN 23109; Watson et al. GCN 23110; Schweyer et al. GCN 23111) in both filters with the following magnitudes:
```
Mid time from GRB����� Exposure�������� Filter Magnitude
trigger time (hrs)���� (s)
---------------------------------------------------------------------
0.55������������������ 5x60������������ SDSS r'�������� 19.54 +- 0.08
0.70������������������ 5x60������������ SDSS i'�������� 19.24 +- 0.07
---------------------------------------------------------------------
```
as calibrated against nearby Pan-STARRS objects.
GCN Circular #23113
N.Tiurina, V. Lipunov, E. Gorbovskoy, V.Kornilov, A.Kuznetsov, V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, D. Vlasenko Lomonosov Moscow State University,SAI
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias (IAC)
D. Buckley, South African Astronomical Observatory (SAAO)
A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory
R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA)
H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University (ISU)
A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University (BSPU)
We have already reported the observation of the optical transient GRB 180809B (Moss et al., GCN # 23105) by one of the telescopes of the MASTER Global Network (Lipunov et al., GCN 23109).
Here we report on the triple independent, automatic detection of the optical transient (also found by Swift UVOT (Moss et al., GCN 23105)). The relatively later guidance of the three MASTER robotic telescopes is due to the fact that the first socket message did not indicate the time of the trigger. As a result, everyone went to the CALET Alert (trig number 1217881726) with poor defined coordinates. Nevertheless, we were able to obtain detailed light curves with a maximum in 4 polarizations.
MASTER-SAAO robotic telescope (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 GRB180809.85 16 sec after notice time and 111 sec after trigger time at 2018-08-09 20:30:39 UT. On our 1-th (10s exposure) set in two polarizations (/\), obtained 111 sec after tigger time at 2018-08-09 20:30:39 UT, we found 1 optical transient within SWIFT error-box (ra=299.7 dec=-15.2989 r=0.05) brighter then 17.4.
```
  T-Tmid      Date   Time       Expt.        Ra                Dec        Mag
    s                 UT         s
-------|--------------------|-------|-----------------|---------------|-------
   116    2018-08-09 20:30:39    10    (19h 58m 48.0s , -15d 17m 57.1s)   16.5
```
The 5-sigma upper limit has been about 17.9 mag
The observations started on zenit distance = 21 deg., galactic latitude b = -22 deg. The moon ( 4 % bright part) was below the horizon (The altitude of the Moon = -75 deg ). The sun altitude = -56.3 degree. The object can be observed till 2018-08-10 04:03:58 UT.
MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the GRB180809.85 35 sec after notice time and 133 sec after trigger time at 2018-08-09 20:31:01 UT. On our first (10s exposure) set we found 1 optical transient within SWIFT error-box (ra=299.7 dec=-15.2989 r=0.05) brighter then 17.9:
```
T-Tmid   Date      Time       Expt.        Ra                Dec           Mag
   s                UT         s
------|--------------------|-------|-----------------|-----------------|-------
  138    2018-08-09 20:31:01    10    ( 19h 58m 48.0s , -15d 17m 56.5s)    16.8
```
The 5-sigma upper limit has been about 17.9 mag
The observations made on zenit distance = 60 degrees, galaxy latitude b = -22 degree. The moon ( 4 % bright part) below the horizon (The altitude of the Moon is -25 degree ). The sun altitude is -27.0 degree. The object can be observed till 2018-08-10 01:29:20.
MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the GRB180809.85 120 sec after notice time and 147 sec after trigger time at 2018-08-09 20:31:15 UT in two polarizations (|-). On our first set, obtained we found 1 optical transient within SWIFT error-box (ra=299.7 dec=-15.2989 r=0.05):
```
  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
   152      2018-08-10 20 31 15     20   ( 19h 58m 43.3s , -15d 20m 37.9s)     15.5
```
The 5-sigma upper limit has been about 16.0 magThe message may be cited.
The observations made on zenit distance = 44 degrees, galaxy latitude b = -22 degree. The moon ( 3 % bright part) below the horizon (The altitude of the Moon is -41 degree ). The sun altitude is -9.1 deg. The object can be observed till 2018-08-10 05:19:05 UT.
The message may be cited.
GCN Circular #23114
J. Japelj (U. Amsterdam), D. B. Malesani (DAWN/NBI and DARK/NBI), J. Selsing (DAWN/NBI), N. R. Tanvir (U. Leicester), D. A. Kann (HETH/IAA-CSIC), V. D'Elia (ASI-SSDC), G. Pugliese (U. Amsterdam), K. E. Heintz (Univ. Iceland and DAWN/NBI), J. P. U. Fynbo (DAWN/NBI), A. J. Levan (Univ. Warwick), P. Schady (University of Bath), report on behalf of the Stargate collaboration:
We observed the field of GRB 180809B with the ESO VLT UT2 (Kueyen), using the X-shooter acquisition camera. In a single 120-s r-band exposure, with a mean epoch Aug 10.055 UT (4.84 hr after the GRB), we detect no object at the position of the optical afterglow (e.g., Moss et al., GCN 23105; Lipunov et al., GCN 23109; Schweyer et al. GCN 23111; Guidorzi et al., GCN 23112, Tiurina et al., GCN 23113), down to a limiting magnitude r > 24.7 AB (calibrated against nearby Pan-STARRS sources).
Compared to the r-band measurement by Guidorzi et al. (GCN 23112), and assuming an unbroken power-law decay F(t) propto t^-alpha, the corresponding decay index is alpha > 2.2 between 0.55 and 4.84 hr after the GRB.
We acknowledge excellent support from the observing team in Paranal, including Steffen Mieske and Boris Haeussler.
GCN Circular #23116
M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena) and the CALET collaboration:
The long, bright GRB 180809B (Swift-BAT trigger #852553: Moss et al., GCN Circ. 23105) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 20:28:41.478 UTC on 9 August 2018 while exiting the radiation belts. The burst signal was seen by all CGBM detectors.
The burst light curve shows the main multi-peaked emission episode which starts at T-5 sec, peaks at T+41.4 sec, and ends at T+79.9 sec, followed by a weaker pulse which starts at T+210.0 sec and ends at T+254.6 sec. The T90 and the T50 durations measured by the SGM data are 227.6 +- 5.4 sec and 28.3 +- 5.7 sec (40-1000 keV), respectively. Since the CGBM HV was set to its nominal value at T-21 sec for the HXM1 and HXM2 detectors and at T-5 sec for the SGM detector, CGBM was blind to a possible earlier emission.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1217881726/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #23120
GRB 180809B: Swift/UVOT Detection
S. Sebzda (PSU) and M. Moss (George Washington University) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180809B 82 s after the BAT trigger (Moss et al., GCN Circ. 23105). A fading source consistent with the XRT position (Moss et al. GCN Circ. 23105) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
    RA  (J2000) =  19:58:47.96 = 299.69984 (deg.)
    Dec (J2000) = -15:17:57.1  = -15.29920 (deg.)
```
with an estimated uncertainty of 0.48 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               81          231          293         18.99+-0.07
white              573         6926          441        >21.55
v                  623         7289          444        >19.8
b                  549         6721          294        >20.9
u                  294         6516          520        >21.0
w1                 672        13027          915        >20.7
m2                 648        11053          906        >20.9
w2                 599        16967         1262        >21.3
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.16 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #23123
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), M. J. Moss (GWU), D. M. Palmer (LANL), T. Sakamoto (AGU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180809B (trigger #852553) (Moss et al., GCN Circ. 23105). The BAT ground-calculated position is RA, Dec = 299.712, -15.293 deg which is
```
  RA(J2000)  =  19h 58m 50.8s
  Dec(J2000) = -15d 17' 34.0"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 63%.
The mask-weighted light curve shows a multi-peaked structure that starts at ~T-36 s and ends at ~T+80 s, followed by another pulse that starts at ~T+200 s and ends at ~T+250 s. The total burst emission ends at ~T+300 s. T90 (15-350 keV) is 233.2 +- 1.1 sec (estimated error including systematics).
We note that the later pulse overlaps with the XRT flare and some ground-based optical observations (e.g. Tiurina et al.; GCN #23113), which indicates an increase in the optical magnitude from Mag 16.5 to 15.5 at the pulse time.
The time-averaged spectrum from T-36.1 to T+302.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.02. The fluence in the 15-150 keV band is 7.3 +- 0.1 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+35.10 sec in the 15-150 keV band is 26.3 +- 0.6 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/852553/BA/
GCN Circular #23124
E. Mazaeva (IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI), A. Volnova (IKI), report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 180809B (Moss et al., GCN 23105) with ZTSH 2.6m telescope of CrAO observatory starting on Aug. 9 (UT) 21:14:58. We took several images in BVRI filters with exposures of 120 s. We detect the afterglow (e.g., Moss et al., GCN 23105; Lipunov et al., GCN 23109; Schweyer et al. GCN 23111; Guidorzi et al., GCN 23112, Tiurina et al., GCN 23113). Preliminary photometry of the afterglow in R- filter is following
```
UT start              t-T0    Filter  Exp.     OT    err
                      (mid, days)       (s)

21:14:58.579          0.03276 R       1*120    19.80 0.05
21:17:05.489          0.03423 R       1*120    19.86 0.04
21:19:12.801          0.03570 R       1*120    19.93 0.05
21:25:54.597          0.04035 R       1*120    20.35 0.05
21:34:27.347          0.04629 R       1*120    20.86 0.08
21:43:00.178          0.05519 R       2*120    21.51 0.11
```
The photometry is based on nearby USNO-B1.0 stars:
Ref.stars
```
USNO-B1.0_id	R2
0747-0765959	19.65
0746-0776364	18.76
0746-0776499	19.18
```
GCN Circular #23125
Z. Liu (NAOC / U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and M.J. Moss report on behalf of the Swift-XRT team:
We have analysed 3.9 ks of XRT data for GRB 180809B (Moss et al. GCN Circ. 23105), from 74 s to 12.6 ks after the BAT trigger. The data comprise 1.7 ks in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. Using 1724 s of PC mode data and 4 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 299.69997, -15.29893 which is equivalent to:
```
RA (J2000): 19h 58m 47.99s
Dec(J2000): -15d 17' 56.1"
```
with an uncertainty of 1.4 arcsec (radius, 90% confidence).
The late-time light curve (from T0+4.7 ks) can be modelled with a power-law decay with a decay index of alpha=1.37 (+/-0.12).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.609 (+/-0.017). The best-fitting absorption column is 2.29 (+0.09, -0.08) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.63 (+/-0.11) and a best-fitting absorption column of 2.4 (+/-0.5) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.6 x 10^-11 (5.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.4 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 1.2 x 10^21 cm^-2
Excess significance: 4.0 sigma
Photon index:	     1.63 (+/-0.11)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00852553.
This circular is an official product of the Swift-XRT team.

GCN Circular #23127
Y. Kilic, M. Dindar, T. Ozisik, M. T. Ozkan, S. Ozdemir TUBITAK National Observatory (TUG)
TUG T60 robotic telescope (http://tug.tubitak.gov.tr/en/teleskoplar/t60-0, Dindar, M. et al. Exp Astron (2015)) located in TUBITAK National Observatory in Antalya was pointed to GRB180809B (Moss et al. GCN 23105) field 54 seconds after receiving the alert and began to take the exposure. In total, 8 R filter images and 4 B filter images were taken with the FLI PL 3041 CCD camera. No source could be detected on B filter. The GRB180809B is detected in the all the images observed in the R filter within the SWIFT error-box. Astrometry was made with the astrometry.net and magnitudes were estimated using the NOMAD catalog.

T-Tmid      Date      Time       Expt.        Ra                Dec        Mag.
   s                   UT         s                                         R
---------|---------------------|-------|-----------------|---------------|----
      64   2018-08-09 20:31:13    20     19h 58m 48.0s   -15d 17m 56.7s   16.07
      91   2018-08-09 20:31:39    20     19h 58m 48.0s   -15d 17m 56.7s   16.24
     117   2018-08-09 20:32:05    20     19h 58m 48.0s   -15d 17m 56.7s   16.52
     183   2018-08-09 20:33:12    60     19h 58m 48.0s   -15d 17m 56.7s   16.29
     249   2018-08-09 20:34:18    60     19h 58m 48.0s   -15d 17m 56.7s   16.59
     316   2018-08-09 20:35:25    60     19h 58m 48.0s   -15d 17m 56.7s   16.90
     382   2018-08-09 20:36:31    60     19h 58m 48.0s   -15d 17m 56.7s   17.20
     449   2018-08-09 20:37:38    60     19h 58m 48.0s   -15d 17m 56.7s   17.37

GCN Circular #23128
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A.Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 180809B (Swift-BAT detection: Moss et al., GCN Circ. 23105; CALET-GBM detection: Cherry, et al., GCN Circ. 23116) triggered Konus-Wind at T0=73730.033 s UT (20:28:50.033).
The burst light curve shows a bright multi-peaked emission episode which starts at ~T0-4 s and has a duration of ~80 s, followed by a weaker episode at ~T0-205 s. The total burst duration is ~300 s. The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180809_T73730/
As observed by Konus-Wind, the burst had a fluence of 3.07(-0.30,+0.36)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+37.952 s, of 2.66(-0.41,+0.42)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst (measured from T0 to T0+252.672 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.87(-0.10,+0.12), the high energy photon index beta = -2.44(-0.24,+0.19), the peak energy Ep = 275(-30,+25) keV (chi2 = 123/97 dof).
The spectrum near the maximum count rate (measured from T0+36.608 to T0+38.144 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.77(-0.12,+0.15), the high energy photon index beta = -2.20(-0.21,+0.15), the peak energy Ep = 525(-95,+103) keV (chi2 = 66/68 dof).
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #23133
Z. Kostrzewa-Rutkowska (SRON/RU), E. Callis (UCD), R. Stein (HU Berlin/DESY), P. D'Avanzo (INAF-OAB), M. Fraser (UCD), J. Lyman (Warwick), D. B. Malesani (DAWN/NBI and DARK/NBI), C. Inserra (Southampton), E. Kankare (QUB), K. Maguire (QUB), S. J. Smartt (QUB), O. Yaron (Weizmann), D. R. Young (QUB), I. Manulis (Weizmann) report:
We observed the field of GRB 180809B (Moss et al., GCN Circ. 23105) under the extended Public ESO Spectroscopic Survey for Transient Objects (ePESSTO; see Smartt et al. 2015, A&A, 579, 40 http://www.pessto.org ). The observations were performed on the ESO New Technology Telescope at La Silla with the SofI instrument in imaging mode starting on 2018-08-12 between 03:38 and 04:27 UT (i.e. about 2.298 and 2.332 days from the burst) with the H filter.
The NIR counterpart (Schweyer et al. GCN Circ. 23111) is clearly detected. From preliminary photometry, we estimate a magnitude of H ~ 20.3 (Vega, calibrated against the 2MASS catalogue). Compared to earlier reports (Schweyer et al. GCN Circ. 23111), our measure indicates significan fading. However, we cannot assess if we already reached the host galaxy level.
GCN Circular #23144
V. Sharma (IUCAA), V. Bhalerao (IIT-B), D. Bhattacharya (IUCAA), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:
Analysis of AstroSat CZTI data showed the detection of a long GRB 180809B, which was also detected by Swift (Moss M. J. et al., GCN 23105), CALET (Cherry M. L. et al., GCN 23116) and Konus-Wind (Svinkin D. et al., GCN 23128).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 20:29:23.500 UT. The measured peak count rate is 2562 cts/s above the background in combined data of four quadrants, with a total of 38208 cts. The local mean background count rate was 501 cts/s. Using cumulative rates, we measure a T90 of 44.1 s. In preliminary analysis, we find that 3257 compton events are associated with this event.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.

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Jochen Greiner, last update: 17-Aug-2018 [Disclaimer]