Gamma-ray Burst 190926A

(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 26 Sep 19 09:53:32 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     926515,   Seg_Num: 0
GRB_RA:          100.599d {+06h 42m 24s} (J2000),
                 101.035d {+06h 44m 08s} (current),
                  99.492d {+06h 37m 58s} (1950)
GRB_DEC:         +59.511d {+59d 30' 40"} (J2000),
                 +59.490d {+59d 29' 26"} (current),
                 +59.560d {+59d 33' 35"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1415 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        18752 TJD;   269 DOY;   19/09/26
GRB_TIME:        35536.35 SOD {09:52:16.35} UT
GRB_PHI:         114.65 [deg]
GRB_THETA:        28.63 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.13 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -2  +0  +0  -5  +0 
SUN_POSTN:       182.78d {+12h 11m 08s}   -1.20d {-01d 12' 17"}
SUN_DIST:         86.86 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      152.96d {+10h 11m 51s}  +15.05d {+15d 02' 59"}
MOON_DIST:        58.26 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       96.65, 36.32 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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 = 4.30,20.21 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 26 Sep 19 09:55:08 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     926515,   Seg_Num: 0
GRB_RA:          100.5699d {+06h 42m 16.7s} (J2000),
                 101.0061d {+06h 44m 01.4s} (current),
                  99.4630d {+06h 37m 51.1s} (1950)
GRB_DEC:         +59.5292d {+59d 31' 45.1"} (J2000),
                 +59.5086d {+59d 30' 31.0"} (current),
                 +59.5776d {+59d 34' 39.4"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       161 [cnts]
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35670.43 SOD {09:54:30.43} UT,   134.1 [sec] since BAT Trigger Time
CENTROID_X:      355.86,  raw= 356  [pixels]
CENTROID_Y:      312.13,  raw= 312  [pixels]
ROLL:            97.38 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   33.09
GRB_POS_XRT_Z:   114.23
IMAGE_URL:       sw00926515000msxps_rw.img
SUN_POSTN:       182.78d {+12h 11m 08s}   -1.21d {-01d 12' 19"}
SUN_DIST:         86.88 [deg]   Sun_angle= 5.5 [hr] (West of Sun)
MOON_POSTN:      152.98d {+10h 11m 55s}  +15.04d {+15d 02' 41"}
MOON_DIST:        58.30 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.06, 22.02 [deg] galactic lon,lat of the burst
ECL_COORDS:       96.63, 36.33 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 26 Sep 19 09:54:58 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     926515,   Seg_Num: 0
GRB_RA:          100.5699d {+06h 42m 16.77s} (J2000),
                 101.0061d {+06h 44m 01.46s} (current),
                  99.4630d {+06h 37m 51.10s} (1950)
GRB_DEC:         +59.5292d {+59d 31' 45.1"} (J2000),
                 +59.5086d {+59d 30' 31.0"} (current),
                 +59.5776d {+59d 34' 39.4"} (1950)
GRB_ERROR:       4.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       5.87e-09 [erg/cm2/sec]
GRB_SIGNIF:      12.68 [sigma]
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35670.43 SOD {09:54:30.43} UT,   134.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.16 261.62 243.58
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       182.78d {+12h 11m 08s}   -1.21d {-01d 12' 18"}
SUN_DIST:         86.88 [deg]   Sun_angle= 5.5 [hr] (West of Sun)
MOON_POSTN:      152.98d {+10h 11m 55s}  +15.05d {+15d 02' 43"}
MOON_DIST:        58.29 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.06, 22.02 [deg] galactic lon,lat of the burst
ECL_COORDS:       96.63, 36.33 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.40 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 26 Sep 19 09:55:10 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     926515,   Seg_Num: 0
GRB_RA:          100.5699d {+06h 42m 16.7s} (J2000),
                 101.0061d {+06h 44m 01.4s} (current),
                  99.4630d {+06h 37m 51.1s} (1950)
GRB_DEC:         +59.5292d {+59d 31' 45.1"} (J2000),
                 +59.5086d {+59d 30' 31.0"} (current),
                 +59.5776d {+59d 34' 39.4"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       161 [cnts]
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35670.43 SOD {09:54:30.43} UT,   134.1 [sec] since BAT Trigger Time
CENTROID_X:      355.86,  raw= 356  [pixels]
CENTROID_Y:      312.13,  raw= 312  [pixels]
ROLL:            97.38 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   33.09
GRB_POS_XRT_Z:   114.23
IMAGE_URL:       sw00926515000msxps_rw.img
SUN_POSTN:       182.78d {+12h 11m 08s}   -1.21d {-01d 12' 19"}
SUN_DIST:         86.88 [deg]   Sun_angle= 5.5 [hr] (West of Sun)
MOON_POSTN:      152.98d {+10h 11m 55s}  +15.04d {+15d 02' 41"}
MOON_DIST:        58.30 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.06, 22.02 [deg] galactic lon,lat of the burst
ECL_COORDS:       96.63, 36.33 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 26 Sep 19 09:56:37 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     926515,   Seg_Num: 0
GRB_RA:          100.599d {+06h 42m 24s} (J2000),
                 101.035d {+06h 44m 08s} (current),
                  99.492d {+06h 37m 58s} (1950)
GRB_DEC:         +59.511d {+59d 30' 40"} (J2000),
                 +59.490d {+59d 29' 26"} (current),
                 +59.560d {+59d 33' 35"} (1950)
GRB_DATE:        18752 TJD;   269 DOY;   19/09/26
GRB_TIME:        35536.35 SOD {09:52:16.35} UT
TRIGGER_INDEX:   20000
GRB_PHI:         114.65 [deg]
GRB_THETA:        28.63 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.13 [sigma]
LC_URL:          sw00926515000msb.lc
SUN_POSTN:       182.78d {+12h 11m 08s}   -1.21d {-01d 12' 20"}
SUN_DIST:         86.86 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      152.99d {+10h 11m 59s}  +15.04d {+15d 02' 24"}
MOON_DIST:        58.29 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       96.65, 36.32 [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 an image 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 = 4.30,20.21 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 26 Sep 19 09:58:13 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.629d {+06h 42m 31s} (J2000)
POINT_DEC:       +59.517d {+59d 30' 59"} (J2000)
POINT_ROLL:      97.377d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35680.77 SOD {09:54:40.77} UT,   144.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.536
N_STARS:         60
X_OFFSET:        232 [pixels]
Y_OFFSET:        610 [pixels]
X_MAX:           1191 [pixels]
Y_MAX:           1569 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00926515000msufc0144.fits
SUN_POSTN:       182.78d {+12h 11m 08s}   -1.21d {-01d 12' 22"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.01d {+10h 12m 03s}  +15.04d {+15d 02' 06"}
MOON_DIST:        58.29 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 26 Sep 19 09:58:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.629d {+06h 42m 31s} (J2000)
POINT_DEC:       +59.517d {+59d 30' 59"} (J2000)
POINT_ROLL:      97.377d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35680.77 SOD {09:54:40.77} UT,   144.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.536
N_STARS:         60
X_OFFSET:        232 [pixels]
Y_OFFSET:        610 [pixels]
X_MAX:           1191 [pixels]
Y_MAX:           1569 [pixels]
DET_THRESH:      18
PHOTO_THRESH:    10
SL_URL:          sw00926515000msufc0144.fits
SUN_POSTN:       182.78d {+12h 11m 08s}   -1.21d {-01d 12' 22"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.01d {+10h 12m 03s}  +15.03d {+15d 02' 03"}
MOON_DIST:        58.29 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [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 26 Sep 19 09:59:25 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.629d {+06h 42m 31s} (J2000)
POINT_DEC:       +59.517d {+59d 30' 59"} (J2000)
ROLL:            97.377d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35680.77 SOD {09:54:40.77} UT,   144.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     591184504
X_OFFSET:        552 [pixels]
Y_OFFSET:        930 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       712
Y_GRB_POS:       1090
BINNING_INDEX:   1
IM_URL:          sw00926515000msuni0168.fits
SUN_POSTN:       182.79d {+12h 11m 08s}   -1.21d {-01d 12' 23"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.02d {+10h 12m 06s}  +15.03d {+15d 01' 53"}
MOON_DIST:        58.29 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [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 26 Sep 19 09:59:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.629d {+06h 42m 31s} (J2000)
POINT_DEC:       +59.517d {+59d 30' 59"} (J2000)
ROLL:            97.377d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35680.77 SOD {09:54:40.77} UT,   144.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     591184504
X_OFFSET:        552 [pixels]
Y_OFFSET:        930 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       712
Y_GRB_POS:       1090
BINNING_INDEX:   1
IM_URL:          sw00926515000msuni0168.fits
SUN_POSTN:       182.79d {+12h 11m 09s}   -1.21d {-01d 12' 23"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.03d {+10h 12m 06s}  +15.03d {+15d 01' 51"}
MOON_DIST:        58.30 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [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 26 Sep 19 10:04:41 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.632d {+06h 42m 32s} (J2000)
POINT_DEC:       +59.515d {+59d 30' 55"} (J2000)
POINT_ROLL:      97.380d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35839.16 SOD {09:57:19.16} UT,   302.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.038
N_STARS:         37
X_OFFSET:        232 [pixels]
Y_OFFSET:        610 [pixels]
X_MAX:           1191 [pixels]
Y_MAX:           1569 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00926515000msufc0302.fits
SUN_POSTN:       182.79d {+12h 11m 09s}   -1.21d {-01d 12' 28"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.08d {+10h 12m 19s}  +15.01d {+15d 00' 54"}
MOON_DIST:        58.33 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 26 Sep 19 10:04:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.632d {+06h 42m 32s} (J2000)
POINT_DEC:       +59.515d {+59d 30' 55"} (J2000)
POINT_ROLL:      97.380d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35839.16 SOD {09:57:19.16} UT,   302.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.038
N_STARS:         37
X_OFFSET:        232 [pixels]
Y_OFFSET:        610 [pixels]
X_MAX:           1191 [pixels]
Y_MAX:           1569 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00926515000msufc0302.fits
SUN_POSTN:       182.79d {+12h 11m 09s}   -1.21d {-01d 12' 28"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.08d {+10h 12m 19s}  +15.01d {+15d 00' 51"}
MOON_DIST:        58.33 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [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 26 Sep 19 10:06:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.632d {+06h 42m 32s} (J2000)
POINT_DEC:       +59.515d {+59d 30' 55"} (J2000)
ROLL:            97.380d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35839.16 SOD {09:57:19.16} UT,   302.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     591184662
X_OFFSET:        552 [pixels]
Y_OFFSET:        930 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       712
Y_GRB_POS:       1090
BINNING_INDEX:   1
IM_URL:          sw00926515000msuni0326.fits
SUN_POSTN:       182.79d {+12h 11m 09s}   -1.21d {-01d 12' 29"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.09d {+10h 12m 22s}  +15.01d {+15d 00' 38"}
MOON_DIST:        58.34 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [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 26 Sep 19 10:06:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     926515,   Seg_Num: 0
POINT_RA:        100.632d {+06h 42m 32s} (J2000)
POINT_DEC:       +59.515d {+59d 30' 55"} (J2000)
ROLL:            97.380d
IMG_START_DATE:  18752 TJD;   269 DOY;   19/09/26
IMG_START_TIME:  35839.16 SOD {09:57:19.16} UT,   302.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     591184662
X_OFFSET:        552 [pixels]
Y_OFFSET:        930 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       712
Y_GRB_POS:       1090
BINNING_INDEX:   1
IM_URL:          sw00926515000msuni0326.fits
SUN_POSTN:       182.79d {+12h 11m 10s}   -1.21d {-01d 12' 29"}
SUN_DIST:         86.85 [deg]   Sun_angle= 5.4 [hr] (West of Sun)
MOON_POSTN:      153.09d {+10h 12m 22s}  +15.01d {+15d 00' 36"}
MOON_DIST:        58.34 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      156.09, 22.05 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       96.67, 36.32 [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 Circular #25848
A. Melandri (INAF-OAB), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), P. A. Evans (U Leicester), J.D. Gropp (PSU), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team:
At 09:52:16 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190926A (trigger=926515). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 100.599, +59.511 which is
```
   RA(J2000) = 06h 42m 24s
   Dec(J2000) = +59d 30' 40"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Since this is an image trigger, the BAT light curve showed no significant structure.
The XRT began observing the field at 09:54:30.4 UT, 134.0 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 100.5699, 59.5292 which is equivalent to:
```
   RA(J2000)  = 06h 42m 16.78s
   Dec(J2000) = +59d 31' 45.1"
```
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 84 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
The initial flux in the 2.5 s image was 5.87e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 144 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 0.06.
Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular #25849
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the Swift GRB190926.41 (trigger No 926515,06h 42m 23.760s , +59d 30m 39.60s, R=0.05) errorbox 1124 sec after notice time and 1233 sec after trigger time at 2019-09-26 10:12:49 UT, with upper limit up to 18.0 mag. Observations started at twilight. The observations began at zenit distance = 71 deg. The sun altitude is -8.9 deg.
The galactic latitude b = -60 deg., longitude l = 98 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1150077
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

    1263 |         MASTER-Amur |  P/ |    60 | 13.9 |        
    1607 |         MASTER-Amur |  P/ |    60 | 14.1 |        
    2561 |         MASTER-Amur |   C |   180 | 17.9 |        
    2770 |         MASTER-Amur |   C |   180 | 18.0 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #25850
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 3630 s of XRT Photon Counting mode data and 3 UVOT images for GRB 190926A, 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 = 100.57044, +59.52920 which is equivalent to:
```
RA (J2000): 06h 42m 16.90s
Dec (J2000): +59d 31' 45.1"
```
with an uncertainty of 2.0 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 #25851
B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB) and A. Melandri report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 190926A (Melandri et al. GCN Circ. 25848), from 140 s to 23.8 ks after the BAT trigger. The data comprise 685 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 25850).
The late-time light curve (from T0+4.1 ks) can be modelled with an initial power-law decay with an index of alpha=0.661 (+0.053, -0.030), followed by a break at T+677 s to an alpha of 3.34 (+0.30, -0.12).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.804 (+/-0.023). The best-fitting absorption column is 3.00 (+/-0.11) x 10^21 cm^-2, in excess of the Galactic value of 7.5 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.1 x 10^-11 (5.5 x 10^-11) erg cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
```
Total column:	     3.00 (+/-0.11) x 10^21 cm^-2
Galactic foreground: 7.5 x 10^20 cm^-2
Excess significance: 33.3 sigma
Photon index:	     1.804 (+/-0.023)
```
If the light curve continues to decay with a power-law decay index of 3.34, the count rate at T+24 hours will be 3.2 x 10^-6 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x 10^-16 (1.7 x 10^-16) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00926515.
This circular is an official product of the Swift-XRT team.
GCN Circular #25852
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 190926A (Melandri et al., GCN 25848) starting at ~59 minutes after the burst. Observations were performed in the clear (roughly R) filters, a total of 102 images were obtained and the exposure time was 60 s per image. We do not detect any optical afterglow candidate within the Enhanced XRT position error circle (Goad et al., GCN 25850), neither in single image, nor in the co-add images. The typical limiting magnitude of our single clear image is about 19.0 mag.
GCN Circular #25853
S. R. Oates (U.Warwick) and A. Melandri (INAF-OAB) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 190926A 144 s after the BAT trigger (Melandri et al., GCN Circ. 25848). No optical afterglow consistent with the enhanced XRT position (Goad et al. GCN Circ. 25850) 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           144          294          147         >20.2
u_FC               303          553          246         >19.3
white              144         6525          580         >20.9
v                  634        11670         1116         >20.0
b                  559         6321          432         >20.2
u                  303         6115          659         >20.0
w1                 685         5910          413         >19.8
m2                 659        12294         1022         >20.3
w2                 610        10756         1148         >20.6
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #25854
R. Adachi, K. L. Murata, M. Oeda, K.Shiraishi, K. Iida, M. Niwano, F. Ogawa, R. Hosokawa, S. Toma, Y. Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 190926A (A. Melandri et al., GCN Circular #25848) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 16:16:33 UT. We did not find any new point sources within the XRT circle (M.R. Goad et al., GCN Circular #25850) in all three bands. We obtained the following 5-sigma limits for the magnitudes.
```
T0+[hour]   MID-UT    T-EXP[sec]    5-sigma limits
------------------------------------------------------------------------------------------------
 ~7.0         18:13:34    6960              g'>19.8, Rc>19.5, Ic>19.2
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used UCAC4 catalog for flux calibration. The magnitudes are expressed in the AB system.
GCN Circular #25856
D. A. Kann, M. Blazek (both HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, K. Bensch, J. F. Agui (all HETH/IAA-CSIC), and A. Sota (IAA-CSIC) report:
We observed the field of GRB 190926A (Melandri et al. GCN #25848) with the 1.5m OSN telescope, at Sierra Nevada Observatory (Granada, Spain). The observation is centered 0.7321 days after the GRB and consisted of 41 x 180 s exposures in the Ic band for a total exposure time of 7380 s.
No new object is detected within the refined XRT error circle (Goad et al. GCN #25850) down to a 3-sigma limit of Ic(AB) = 23.6 mag, as compared to stars of the PanSTARRS catalog. This is in agreement with other non-detections (Lipunov et al., GCN #25849, Zheng & Filippenko, GCN # 25852, Oates & Melandri, GCN #25853, Adachi et al., GCN #25854); and the very high-significance detection of excess hydrogen column density in the XRT observations (Sbarufatti et al., GCN #25851) indicates this is a dark GRB, and less likely a high-redshift one.
GCN Circular #25860
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 190926*A (trigger #926515) (Melandri, et al., GCN Circ. 25848). The BAT ground-calculated position is RA, Dec = 100.616, 59.531 deg which is
```
  RA(J2000)  =  06h 42m 27.9s 
  Dec(J2000) = +59d 31' 51.2" 
```
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 50%.
The BAT mask-weighted light curve shows a complex structure with multiple peaks extending from roughly T-120 sec to T+450 sec. T90 (15-350 keV) is 368.9 +- 20.9 sec (estimated error including systematics).
The time-averaged spectrum from T-0.00 to T+395.46 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.14 +- 0.18. The fluence in the 15-150 keV band is 2.5 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+52.95 sec in the 15-150 keV band is 0.6 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/926515/BA/
GCN Circular #25862
S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO, Samtskhe-Javakheti State University), E. Mazaeva (IKI), A. Volnova (IKI), V. R. Ayvazian (AbAO, Samtskhe-Javakheti State University), G.V. Kapanadze (AbAO, Samtskhe-Javakheti State University), I. Molotov (KIAM) report on behalf of larger IKI GRB follow-up collaboration:
We observed GRB 190926A (Melandri et al., GCN 25848) with AS-32 (0.7m) telescope of Abastumani Observatory starting on Sep. 27 (UT) 01:16:46. We obtained several 60 s exposures in R-filter. We do not detect any source within enhanced Swift-XRT position (Goad et al., GCN 25850) in the stacked image. Photometry of the field is following
```
Date       UT start t-T0    Filter Exp.  OT    Err. UL
                    (mid, days) (s)

2019-09-27 01:16:46 0.6493   R    21*60  n/d   n/d  20.8
```
Photometry is based on nearby USNO-B1.0 star (R2 magnitude):
```
USNO-B1.0_id R2
1496-0169403 18.52
```
The non detection in an agreement with previously reported results (Lipunov et al., GCN #25849, Zheng & Filippenko, GCN # 25852, Oates & Melandri, GCN #25853, Adachi et al., GCN #25854; Kann et al., GCN #25856).
GCN Circular #25937
M. Blazek, D. A. Kann (both HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, K. Bensch, J. F. Agui (all HETH/IAA-CSIC), I. Hermelo, and S. Pedraz (both CAHA) report:
We observed the field of GRB 190926A (Melandri et al. GCN #25848) with the 2.2m telescope at Calar Alto Observatory, Spain. The observation is centered 0.6523 days after the GRB and consisted of 3 x 360 s exposures in the V band for a total exposure time of 1080 s, obtained before technical problems shut down the observation sequence.
No new object is detected within the refined XRT error circle (Goad et al. GCN #25850) down to a 3-sigma limit of V(AB) = 21.9 mag, as compared to stars of the GSC 2.3 catalog. This is in agreement with the deep non-detection by OSN (Kann et al., GCN #25856).

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Jochen Greiner, last update: 03-Oct-2019 [Disclaimer]