Gamma-ray Burst 191031D

(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 31 Oct 19 21:32:19 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     932608,   Seg_Num: 0
GRB_RA:          283.275d {+18h 53m 06s} (J2000),
                 283.411d {+18h 53m 39s} (current),
                 282.932d {+18h 51m 44s} (1950)
GRB_DEC:         +47.639d {+47d 38' 19"} (J2000),
                 +47.664d {+47d 39' 51"} (current),
                 +47.576d {+47d 34' 32"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       1205 [cnts]    Image_Peak=93 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10427     E_range: 50-350 keV
BKG_INTEN:       20423 [cnts]
BKG_TIME:        77000.15 SOD {21:23:20.15} UT
BKG_DUR:         8 [sec]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        77011.03 SOD {21:23:31.03} UT
GRB_PHI:         -29.96 [deg]
GRB_THETA:        43.20 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     82.86 [sigma]
IMAGE_SIGNIF:    8.55 [sigma]
MERIT_PARAMS:     +1  +0  +0  -4  +3  -1  +0  +0  -6  +0 
SUN_POSTN:       215.80d {+14h 23m 11s}  -14.23d {-14d 13' 40"}
SUN_DIST:         86.16 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      266.95d {+17h 47m 49s}  -22.24d {-22d 14' 20"}
MOON_DIST:        71.45 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.33, 19.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      296.69, 69.85 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
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 = 259.17,19.09 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(2.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=8402).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:23:55 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      49
TRIGGER_NUM:     594249816
GRB_RA:          293.550d {+19h 34m 12s} (J2000),
                 293.691d {+19h 34m 46s} (current),
                 293.193d {+19h 32m 46s} (1950)
GRB_DEC:         +48.067d {+48d 04' 00"} (J2000),
                 +48.111d {+48d 06' 39"} (current),
                 +47.956d {+47d 57' 23"} (1950)
GRB_ERROR:       4.40 [deg radius, statistical plus systematic]
GRB_INTEN:       2727 [cnts/sec]
DATA_SIGNIF:     71.00 [sigma]
INTEG_TIME:      0.256 [sec]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        77011.13 SOD {21:23:31.13} UT
GRB_PHI:          57.98 [deg]
GRB_THETA:        60.00 [deg]
DATA_TIME_SCALE: 0.2560 [sec]
HARD_RATIO:      0.30
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      62%  GRB
2nd_MOST_LIKELY:  36%  Cyg X-1
DETECTORS:       0,1,1, 0,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       215.79d {+14h 23m 10s}  -14.23d {-14d 13' 33"}
SUN_DIST:         92.71 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      266.87d {+17h 47m 29s}  -22.23d {-22d 13' 50"}
MOON_DIST:        74.34 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       80.51, 13.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      315.09, 67.85 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031891/quicklook/glg_lc_medres34_bn191031891.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 11.35,13.80 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:24:12 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     594249816
GRB_RA:          281.860d {+18h 47m 26s} (J2000),
                 281.964d {+18h 47m 51s} (current),
                 281.597d {+18h 46m 23s} (1950)
GRB_DEC:         +54.180d {+54d 10' 48"} (J2000),
                 +54.203d {+54d 12' 10"} (current),
                 +54.123d {+54d 07' 24"} (1950)
GRB_ERROR:       1.32 [deg radius, statistical only]
DATA_SIGNIF:     77.90 [sigma]
DATA_INTERVAL:   0.256 [sec]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        77011.13 SOD {21:23:31.13} UT
GRB_PHI:          47.00 [deg]
GRB_THETA:        59.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       215.79d {+14h 23m 10s}  -14.23d {-14d 13' 34"}
SUN_DIST:         88.30 [deg]   Sun_angle= -4.4 [hr] (East of Sun)
MOON_POSTN:      266.87d {+17h 47m 29s}  -22.23d {-22d 13' 51"}
MOON_DIST:        77.53 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       83.71, 22.26 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      300.65, 76.35 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031891/quicklook/glg_lc_medres34_bn191031891.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_594249816.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        Bright hard burst in the GBM.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:32:57 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     594249816
GRB_RA:          282.800d {+18h 51m 12s} (J2000),
                 282.901d {+18h 51m 36s} (current),
                 282.546d {+18h 50m 11s} (1950)
GRB_DEC:         +54.960d {+54d 57' 36"} (J2000),
                 +54.985d {+54d 59' 04"} (current),
                 +54.899d {+54d 53' 56"} (1950)
GRB_ERROR:       2.35 [deg radius, statistical only]
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        77011.13 SOD {21:23:31.13} UT
GRB_PHI:          47.00 [deg]
GRB_THETA:        58.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       215.80d {+14h 23m 11s}  -14.23d {-14d 13' 41"}
SUN_DIST:         89.13 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      266.96d {+17h 47m 50s}  -22.24d {-22d 14' 22"}
MOON_DIST:        78.42 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       84.69, 21.95 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      304.08, 76.88 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031891/quicklook/glg_lc_medres34_bn191031891.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031891/quicklook/glg_locplot_all_bn191031891.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice was generated completely by automated pipeline processing.  
COMMENTS:        Bright hard burst in the GBM.  
COMMENTS:        This is likely a Short GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=932608).

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Thu 31 Oct 19 21:24:20 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    8402,   Sub_Num: 0
GRB_INTEN:      15.54 [sigma]  
GRB_TIME:       77009.92 SOD {21:23:29.92} UT
GRB_DATE:       18787 TJD;   304 DOY;   19/10/31
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=1.0000 and Time_Error=0.5000.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(2.0<100sec) coincident with the
+FERMI_GBM event (trignum=594249816). 
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2019-10/2019-10-31T21-23-29.7724-02120-27536-0.lc

GCN NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Thu 31 Oct 19 21:32:53 UT 
NOTICE_TYPE:     Swift-XRT Nack-Position 
TRIGGER_NUM:     932608,   Seg_Num: 0 
POINT_RA:        283.304d {+18h 53m 13s} (J2000) 
POINT_DEC:       +47.636d {+47d 38' 08"} (J2000) 
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31 
IMG_START_TIME:  77099.83 SOD {21:24:59.83} UT,   88.8 [sec] since BAT Trigger Time 
COUNTS:          15    Min_needed= 20 
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec] 
PH2_ITER:        2    Max_iter_allowed= 4 
ERROR_CODE:      1 
COMMENTS:        SWIFT-XRT Nack Position.   
COMMENTS:        No source found in the image.

GCN NOTICE

 
TITLE:           GCN/SWIFT NOTICE 
NOTICE_DATE:     Thu 31 Oct 19 21:34:04 UT 
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     932608,   Seg_Num: 0 
POINT_RA:        283.304d {+18h 53m 13s} (J2000) 
POINT_DEC:       +47.635d {+47d 38' 06"} (J2000) 
POINT_ROLL:      243.841d 
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31 
IMG_START_TIME:  77103.63 SOD {21:25:03.63} UT,   92.6 [sec] since BAT Trigger Time 
FILTER:          10, White 
BKG_MEAN:        1.658 
N_STARS:         127 
X_OFFSET:        638 [pixels] 
Y_OFFSET:        576 [pixels] 
X_MAX:           1597 [pixels] 
Y_MAX:           1535 [pixels] 
DET_THRESH:      11 
PHOTO_THRESH:    5 
SL_URL:          sw00932608000msufc0092.fits 
SUN_POSTN:       215.80d {+14h 23m 12s}  -14.23d {-14d 13' 42"} 
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun) 
MOON_POSTN:      266.97d {+17h 47m 53s}  -22.24d {-22d 14' 26"} 
MOON_DIST:        71.45 [deg] 
MOON_ILLUM:      17 [%] 
GAL_COORDS:       77.34, 19.41 [deg] galactic lon,lat of the pointing direction 
ECL_COORDS:      296.74, 69.84 [deg] ecliptic lon,lat of the pointing direction 
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:34:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.304d {+18h 53m 13s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 06"} (J2000)
POINT_ROLL:      243.841d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77103.63 SOD {21:25:03.63} UT,   92.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.658
N_STARS:         127
X_OFFSET:        638 [pixels]
Y_OFFSET:        576 [pixels]
X_MAX:           1597 [pixels]
Y_MAX:           1535 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00932608000msufc0092.fits
SUN_POSTN:       215.80d {+14h 23m 12s}  -14.23d {-14d 13' 42"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      266.97d {+17h 47m 54s}  -22.24d {-22d 14' 27"}
MOON_DIST:        71.45 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.41 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.74, 69.84 [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 31 Oct 19 21:35:32 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.304d {+18h 53m 13s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 06"} (J2000)
ROLL:            243.841d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77103.63 SOD {21:25:03.63} UT,   92.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     594249927
X_OFFSET:        957 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1117
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw00932608000msuni0116.fits
SUN_POSTN:       215.80d {+14h 23m 12s}  -14.23d {-14d 13' 43"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      266.98d {+17h 47m 56s}  -22.24d {-22d 14' 31"}
MOON_DIST:        71.45 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.41 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.74, 69.84 [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 31 Oct 19 21:35:34 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     932608,   Seg_Num: 0
GRB_RA:          283.275d {+18h 53m 06s} (J2000),
                 283.411d {+18h 53m 39s} (current),
                 282.932d {+18h 51m 44s} (1950)
GRB_DEC:         +47.639d {+47d 38' 19"} (J2000),
                 +47.664d {+47d 39' 51"} (current),
                 +47.576d {+47d 34' 32"} (1950)
GRB_DATE:        18787 TJD;   304 DOY;   19/10/31
GRB_TIME:        77011.13 SOD {21:23:31.13} UT
TRIGGER_INDEX:   10427
GRB_PHI:         -29.96 [deg]
GRB_THETA:        43.20 [deg]
DELTA_TIME:      23.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     82.86 [sigma]
IMAGE_SIGNIF:    8.55 [sigma]
LC_URL:          sw00932608000msb.lc
SUN_POSTN:       215.80d {+14h 23m 12s}  -14.23d {-14d 13' 43"}
SUN_DIST:         86.16 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      266.99d {+17h 47m 56s}  -22.24d {-22d 14' 32"}
MOON_DIST:        71.45 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.33, 19.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      296.69, 69.85 [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 = 259.17,19.09 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:36:57 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     932608,   Seg_Num: 0
GRB_RA:          283.2908d {+18h 53m 09.79s} (J2000),
                 283.4270d {+18h 53m 42.48s} (current),
                 282.9474d {+18h 51m 47.36s} (1950)
GRB_DEC:         +47.6452d {+47d 38' 42.7"} (J2000),
                 +47.6707d {+47d 40' 14.5"} (current),
                 +47.5820d {+47d 34' 55.2"} (1950)
GRB_ERROR:       3.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77112.00 SOD {21:25:12.00} UT,   101.0 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       215.80d {+14h 23m 12s}  -14.23d {-14d 13' 44"}
SUN_DIST:         86.17 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      267.00d {+17h 48m 00s}  -22.24d {-22d 14' 36"}
MOON_DIST:        71.46 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.42 [deg] galactic lon,lat of the burst
ECL_COORDS:      296.73, 69.85 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN Circular #26111
The Fermi GBM team reports the detection of a likely SHORT GRB
At 21:23:31 UT on 31 Oct 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191031D (trigger 594249816.128134 / 191031891).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 282.8, Dec = 55.0 (J2000 degrees, equivalent to J2000 18h 51m, 55d 00'), with a statistical uncertainty of 2.4 degrees.
The angle from the Fermi LAT boresight is 58.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031891/quicklook/glg_skymap_all_bn191031891.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031891/quicklook/glg_healpix_all_bn191031891.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191031891/quicklook/glg_lc_medres34_bn191031891.gif

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:41:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.308d {+18h 53m 14s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 06"} (J2000)
ROLL:            243.845d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77316.60 SOD {21:28:36.60} UT,   305.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     594250140
X_OFFSET:        957 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1117
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw00932608000msuni0329.fits
SUN_POSTN:       215.80d {+14h 23m 13s}  -14.23d {-14d 13' 47"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      267.04d {+17h 48m 10s}  -22.25d {-22d 14' 51"}
MOON_DIST:        71.45 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.75, 69.84 [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 31 Oct 19 21:35:49 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.304d {+18h 53m 13s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 06"} (J2000)
ROLL:            243.841d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77103.63 SOD {21:25:03.63} UT,   92.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     594249927
X_OFFSET:        957 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1117
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw00932608000msuni0116.fits
SUN_POSTN:       215.80d {+14h 23m 12s}  -14.23d {-14d 13' 43"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      266.99d {+17h 47m 57s}  -22.24d {-22d 14' 32"}
MOON_DIST:        71.45 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.41 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.74, 69.84 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:45:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.308d {+18h 53m 14s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 05"} (J2000)
POINT_ROLL:      243.844d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77870.83 SOD {21:37:50.83} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.490
N_STARS:         190
X_OFFSET:        398 [pixels]
Y_OFFSET:        336 [pixels]
X_MAX:           1837 [pixels]
Y_MAX:           1775 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00932608000msufc0859.fits
SUN_POSTN:       215.81d {+14h 23m 14s}  -14.23d {-14d 13' 51"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      267.09d {+17h 48m 21s}  -22.25d {-22d 15' 08"}
MOON_DIST:        71.44 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.75, 69.84 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 31 Oct 19 21:46:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.308d {+18h 53m 14s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 05"} (J2000)
POINT_ROLL:      243.844d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77870.83 SOD {21:37:50.83} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.490
N_STARS:         190
X_OFFSET:        398 [pixels]
Y_OFFSET:        336 [pixels]
X_MAX:           1837 [pixels]
Y_MAX:           1775 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00932608000msufc0859.fits
SUN_POSTN:       215.81d {+14h 23m 14s}  -14.23d {-14d 13' 51"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      267.09d {+17h 48m 22s}  -22.25d {-22d 15' 09"}
MOON_DIST:        71.44 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.75, 69.84 [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 31 Oct 19 21:47:15 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.308d {+18h 53m 14s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 05"} (J2000)
ROLL:            243.844d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77870.83 SOD {21:37:50.83} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     594250694
X_OFFSET:        957 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1117
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw00932608000msuni0883.fits
SUN_POSTN:       215.81d {+14h 23m 14s}  -14.23d {-14d 13' 52"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      267.10d {+17h 48m 24s}  -22.25d {-22d 15' 13"}
MOON_DIST:        71.44 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.75, 69.84 [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 31 Oct 19 21:47:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     932608,   Seg_Num: 0
POINT_RA:        283.308d {+18h 53m 14s} (J2000)
POINT_DEC:       +47.635d {+47d 38' 05"} (J2000)
ROLL:            243.844d
IMG_START_DATE:  18787 TJD;   304 DOY;   19/10/31
IMG_START_TIME:  77870.83 SOD {21:37:50.83} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     594250694
X_OFFSET:        957 [pixels]
Y_OFFSET:        895 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1117
Y_GRB_POS:       1055
BINNING_INDEX:   1
IM_URL:          sw00932608000msuni0883.fits
SUN_POSTN:       215.81d {+14h 23m 14s}  -14.23d {-14d 13' 52"}
SUN_DIST:         86.18 [deg]   Sun_angle= -4.5 [hr] (East of Sun)
MOON_POSTN:      267.11d {+17h 48m 25s}  -22.25d {-22d 15' 14"}
MOON_DIST:        71.44 [deg]
MOON_ILLUM:      17 [%]
GAL_COORDS:       77.34, 19.40 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.75, 69.84 [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 #26112
V. D'Elia (SSDC), E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), D. M. Palmer (LANL) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
At 21:23:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191031D (trigger=932608). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 283.275, +47.639 which is
```
   RA(J2000) = 18h 53m 06s
   Dec(J2000) = +47d 38' 19"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak structure with a duration of about 0.4 sec. The peak count rate was ~18000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 21:24:59.8 UT, 88.8 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 283.2890, 47.6438 which is equivalent to:
```
   RA(J2000)  = 18h 53m 09.37s
   Dec(J2000) = +47d 38' 37.7"
```
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 38 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 92 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 0.08.
This GRB was also detected by Fermi/GBM (trignum=191031891, GCN 26111), and the INTEGRAL/SPIACS event (trignum=8402). We note that the Fermi automated circular has misnamed this event GRB 191031C.
Burst Advocate for this burst is V. D'Elia (delia AT ssdc.asi.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 #26113
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-Tavrida robotic telescope (Global 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 Swift GRB191031.89 (trigger No 932608,18h 53m 06.000s , +47d 38m 20.40s, R=0.05) errorbox 14 sec after notice time and 551 sec after trigger time at 2019-10-31 21:32:42 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 71 deg. The sun altitude is -60.1 deg.
MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) was pointed to the Swift GRB191031.89 errorbox 48 sec after notice time and 585 sec after trigger time at 2019-10-31 21:33:17 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 53 deg. The sun altitude is -43.2 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=1183931
We obtain a following upper limits.

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
     607 |      MASTER-Tavrida |   C |   110 | 16.9 |
     762 |      MASTER-Tavrida |   C |   420 | 17.4 |  Coadd
     646 |          MASTER-IAC |  P| |   120 | 18.4 | 
     811 |          MASTER-IAC |  P| |   450 | 19.0 |  Coadd
     646 |          MASTER-IAC |  P- |   120 | 18.3 |
     745 |      MASTER-Tavrida |   C |   140 | 16.7 |
     808 |          MASTER-IAC |  P| |   150 | 18.5 |
     808 |          MASTER-IAC |  P- |   150 | 18.4 |
     914 |      MASTER-Tavrida |   C |   170 | 16.5 |
    1013 |          MASTER-IAC |  P| |   180 | 18.4 |
    1013 |          MASTER-IAC |  P- |   180 | 18.3 |
    1103 |      MASTER-Tavrida |   C |   180 | 16.0 | 
    1103 |      MASTER-Tavrida |   C |   180 | 15.5 |
    1255 |          MASTER-IAC |  P| |   180 | 18.5 |  
    1255 |          MASTER-IAC |  P- |   180 | 18.3 |
    1304 |      MASTER-Tavrida |   C |   180 | 16.1 |
    1304 |      MASTER-Tavrida |   C |   180 | 15.7 |
    1498 |          MASTER-IAC |  P- |   180 | 18.3 |
    1498 |          MASTER-IAC |  P| |   180 | 18.3 |
    1505 |      MASTER-Tavrida |   C |   180 | 15.9 |
    1505 |      MASTER-Tavrida |   C |   180 | 14.8 |
    1706 |      MASTER-Tavrida |   C |   180 | 15.0 |
    1706 |      MASTER-Tavrida |   C |   180 | 14.1 |
    1738 |          MASTER-IAC |  P| |   180 | 14.8 | 
    1738 |          MASTER-IAC |  P- |   180 | 14.7 |
    1907 |      MASTER-Tavrida |   C |   180 | 14.3 |
    1907 |      MASTER-Tavrida |   C |   180 | 15.8 |
    1989 |          MASTER-IAC |  P| |   180 | 18.4 |  
    1989 |          MASTER-IAC |  P- |   180 | 18.2 | 
    2108 |      MASTER-Tavrida |   C |   180 | 16.6 |  
    2108 |      MASTER-Tavrida |   C |   180 | 16.6 |
    2230 |          MASTER-IAC |  P- |   180 | 18.1 |
    2230 |          MASTER-IAC |  P| |   180 | 18.2 |
    2309 |      MASTER-Tavrida |   C |   180 | 17.2 |
    2309 |      MASTER-Tavrida |   C |   180 | 17.3 |

Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

GCN Circular #26114
B. Mailyan (UAH) reports on behalf of the Fermi GBM Team:
"The Fermi Gamma-ray Burst Monitor (GBM) trigger 594249816/191031891 at 21:23:31 UT on 31 Oct 2019, of GRB 191031C (GCN Circ. #26111) should be GRB 191031D. We apologize for any confusion caused."
GCN Circular #26117
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 722 s of XRT Photon Counting mode data and 1 UVOT images for GRB 191031D, 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 = 283.28951, +47.64407 which is equivalent to:
```
RA (J2000): 18h 53m 9.48s
Dec (J2000): +47d 38' 38.6"
```
with an uncertainty of 1.9 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 #26118
B. Mailyan (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 21:23:31.13 UT on 31 October 2019, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 191031D (trigger 594249816/191031891) which was also detected by the Swift BAT and XRT (D'Elia et al. 2019, GCN 26112) The Fermi GBM Final Real-time Localization (GCN 26111) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 64 degrees.
The GBM light curve shows a short spike with a duration (T90) of about 0.256 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.32 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.42 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 856 +/- 53 keV
The event fluence (10-1000 keV) in this time interval is (4.36 +/- 0.09)E-06 erg/cm^2. The 64 ms peak photon flux measured starting from T0+0.128 s in the 10-1000 keV band is 48.7 +/- 1.59 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular #26120
T. Laskar (Bath), W. Fong, K. D. Alexander, G. Schroeder, K. Paterson (Northwestern) and E. Berger (Harvard) report:
"We observed the position of the short-duration GRB 191031D (Fermi-GBM et al., GCN 26111; D'Elia et al., GCN 26112; Mailyan et al., GCN 26118) with the Karl G. Jansky Very Large Array (VLA) under Program 19B-217 (PI: Fong) beginning on 2019 Oct 31.992 UT (2.4 hr post-burst) at a mean frequency of 9.8 GHz. Based on preliminary analysis, in 1 hour of observations we do not detect any radio emission at or near the position of the XRT afterglow (Osborne et al., GCN 26117) to a 3-sigma limit of 15 microJy. Additional, detailed analysis is ongoing.
We thank Amy Mioduszewski and the rest of the VLA staff for their assistance with rapidly approving and executing these observations. Further observations are planned."
GCN Circular #26121
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), 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 191031D (Fermi GBM Team, GCN Circ. 26111; D'Elia et al., GCN Circ. 26112) 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 2019/11 1.09 to 2019/11 1.12 UTC (4.65 to 5.49 hours after the BAT trigger), obtaining a total of 0.56 hours exposure in the r and i bands, 0.23 hours exposure in the Z and Y bands, and 0.06 hours exposures in the J and H bands.
For a source within the Swift-XRT error circle, in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma):
```
  r	> 22.94
  i	> 23.17
  Z	> 21.50
  Y	> 21.40
  J	> 19.44
  H	> 19.33
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron�mico Nacional in San Pedro M�rtir.
GCN Circular #26122
Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego Gonz�lez (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Margarita Pereyra (UNAM), and Eleonora Troja (GSFC) report:
We observed the field of GRB 191031A (D'Ai et al., GCN Circ. 26101; Fermi GBM Team, GCN Circ. 26102) with the COATLI 50-cm telescope and interim imager at the Observatorio Astron�mico Nacional on the Sierra de San Pedro M�rtir (http://coatli.astroscu.unam.mx) from 2019-11-01 02:47 UTC to 04:49 UTC (5.4 to 7.4 hours after the trigger), obtaining a total of 4530 seconds of exposure in the w filter.
We do not detetect any uncataloged sources in the enhanced XRT error region (Osborne et al., GCN Circ. 26117) to a 3-sigma limit of w = 23.2.
Our w magnitudes are calibrated against the Pan-STARRS1 catalog, are on an approximate AB system (Becerra et al., 2019, ApJ, 872, 118), and are not corrected for Galactic extinction in the direction of the GRB.
We thank the COATLI technical team and the staff of the Observatorio Astron�mico Nacional.
GCN Circular #26123
A. Ursi (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), report on behalf of the AGILE Team:
The AGILE Mini-CALorimeter (MCAL) detected the short GRB 191031D at T0 = 2019-10-31 21:23:28.17 +/- 0.01 s (UTC), already detected by Fermi/GBM (GCN #26111), Swift (D'Elia et al., 2019; GCN #26112), and INTEGRAL/SPIACS (trignum=8402).
The event lasted about 0.2 s and released a total number of ~430 counts in the detector (in the 0.4-100 MeV energy range), above an average background rate of 544 counts / s.
The light curve shows a single peak episode and can be found at http://www.agilescienceapp.it/notices/GRB_064997_499641808.174626.png.
The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.
GCN Circular #26124
B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA) and V. D'Elia report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for GRB 191031D (D'Elia et al. GCN Circ. 26112), from 101 s to 17.5 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 26117).
The light curve can be modelled with a power-law decay with a decay index of alpha=2.04 (+0.22, -0.21).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.90 (+0.26, -0.16). The best-fitting absorption column is consistent with the Galactic value of 6.6 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 3.3 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.6 (+/-2.1) x 10^20 cm^-2
Galactic foreground: 6.6 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.90 (+0.26, -0.16)
```
If the light curve continues to decay with a power-law decay index of 2.04, the count rate at T+24 hours will be 1.9 x 10^-6 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.2 x 10^-17 (7.1 x 10^-17) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00932608.
This circular is an official product of the Swift-XRT team.
GCN Circular #26125
F. Ogawa, R. Adachi, K. L. Murata, M. Oeda, K.Shiraishi, K. Iida, M. Niwano, 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 191031D (The Fermi GBM team, GCN Circular #26111, V. D'Elia et al., GCN Circular #26112, Bagrat Mailyan, #26114) 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 19/11/01 08:18:36 UT. We did not find any new point sources within the XRT circle (J.P. Osborne et al., GCN Circular #26117) in all three bands. We obtained the following 5-sigma limits for the magnitudes.
```
T0+[hour]�� MID-UT��� T-EXP[sec]��� 5-sigma limits
------------------------------------------------------------------------------------------------ 


 �~11.5�������� 09:12:34��� 1680������������� g'>18.3, Rc>18.2, Ic>17.3
------------------------------------------------------------------------------------------------ 
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 #26126
D. Frederiks, S. Golenetskii, R. Aptekar, A. Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report:
The short-duration GRB 191031D (Swift detection: D'Elia et al., GCN Circ. 26112; Fermi GBM detection: Mailyan & Meegan, GCN Circ. 26118; AGILE/MCAL observations: Ursi et al., GCN Circ. 26123) triggered Konus-Wind at T0=77011.324 s UT (21:23:31.324).
The burst light curve shows a mult-peaked pulse which started at ~T0-0.064 s and had a total duration of ~0.35 s. The emission is seen up to ~5 MeV.
As observed by Konus-Wind, the burst had a fluence of 2.72(-0.27, +0.31)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-0.016 s, of 1.95(-0.32,+0.38)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.27(-0.17,+0.20) and Ep = 370(-46,+58) keV (chi2 = 35/39 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.6 (chi2 =35/38 dof).
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB191031_T77011/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #26128
GRB 191031D: Swift/UVOT Upper Limits
J. D. Gropp (PSU) and V. D'Elia (SSDC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 191031D 93 s after the BAT trigger (D'Elia et al., GCN Circ. 26112). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 26117) 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            93          242          147         >20.8
u_FC               306          555          246         >20.2
white               93         6694          575         >21.1
v                  636         5863          294         >19.9
b                  561         6683          471         >20.4
u                  306         6477          697         >20.3
w1                 686         6273          452         >19.8
m2                 661         6067          294         >19.6
w2                 612         5658          294         >19.9
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.08 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #26129
R. Gaikwad, S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), 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 GRB 191031D, which was also detected by Fermi GBM Real-time Localization (GCN #26111), Swift (D'Elia et al., GCN #26112), Swift-XRT (Osborne et al., GCN #26117), Fermi GBM (Mailyan et al., GCN #26118), VLA (Laskar T. et al., GCN #26120), RATIR (Butler N. et al., GCN #26121), COATLI (Watson A. M. et al., GCN #26122), AGILE/MCAL (Ursi A. et al., GCN #26123), MITSuME Akeno (Ogawa F. et al., GCN #26125) and Konus-Wind (Frederiks D. et al., GCN #26126).
The source was clearly detected in the 40-200 keV energy range. The light curve showed single pulse of emission peaking at 2019-10-31 21:23:31.0 UT. The measured peak count rate associated with the burst is 628 cts/s above the background in the combined data of four quadrants, with a total of 393 cts. The local mean background count rate was 556 cts/s. Using cumulative rates, we measure a T90 of 0.35 s.
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.
GCN Circular #26133
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), V. D'Elia (SSDC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), J. P. Norris (BSU), D. M. Palmer (LANL), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 191031D (trigger #932608) (D'Elia, et al., GCN Circ. 26112). The BAT ground-calculated position is RA, Dec = 283.269, 47.645 deg which is
```
 RA(J2000)  =  18h 53m 04.5s 
 Dec(J2000) = +47d 38' 40.9" 
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 37%.
The mask-weighted light curve shows a multi-peak structure from T-0.05 sec to T+0.3 sec with a harder first pulse and softer second pulse. There is no sign of extended emission. T90 (15-350 keV) is 0.29 +- 0.05 sec (estimated error including systematics).
The time-averaged spectrum from T-0.03 to T+0.31 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.80 +- 0.15. The fluence in the 15-150 keV band is 4.1 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.36 sec in the 15-150 keV band is 4.3 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The duration and hardness of GRB 191031D place it squarely within the distribution of short, hard bursts detected by BAT. Using the 4-ms binned light curve, the spectral lag of the burst is 0.2 ms +- 2 ms for the 50-100 keV to 15-25 keV bands, and 0.4 ms +- 3 ms for the 100-350 keV to 25-50 keV bands. These values are consistent with a short GRB.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/932608/BA/
GCN Circular #26134
K. Paterson, W. Fong, K. D. Alexander, G. Schroeder, A. Rouco Escorial (Northwestern) report:
“We observed the field of the short-duration GRB 191031D (Fermi-GBM et al., GCN 26111; D'Elia et al., GCN 26112; Mailyan et al., GCN 26118) with Binospec mounted on the 6.5-m MMT on Mount Hopkins, Arizona, starting on 2019 November 1 at 01:44:13 UT, 4.31 hours after the burst. We obtained 15x120-sec of observations in the r-band in 1.05” seeing and clear conditions.
We do not detect any optical source in or around the enhanced XRT position (Osborne et al. GCN 26117).
We obtain a 3-sigma upper limit of r > 23.5 AB mag on the afterglow or any coincident host galaxy, not corrected for Galactic extinction. Photometry is calibrated to the USNO-B1.0 catalog. This limit is consistent with, and slightly deeper than the limit found by Butler et al. (GCN 26121). We note that the closest, clearly-extended source is 5.48 arcsec to the southwest.
Further observations are planned. We thank the MMT staff, and in particular observer Michael Calkins, for their assistance with these observations.”
GCN Circular #26147
S.Dichiara (UMD, NASA-GSFC) and E. Troja (UMD, NASA-GSFC) report on behalf of a larger collaboration:
We observed the field of the short duration GRB 191031D (Fermi GBM Team, GCN Circ. 26111; D'Elia et al., GCN Circ. 26112) with the Gemini North 8-meter telescope located on Mauna Kea, beginning on 2019-11-02 04:43:08 UT, approximately 1.3 d post-burst. We obtained a series of 6x120s r-band images using the Gemini Multi-Object Spectrograph (GMOS).
No credible counterpart is detected within the enhanced X-ray position (Osborne el al., GCN 26117) down to r > 25 AB mag, not corrected for Galactic extinction.
We thank S. Stewart and the Gemini North staff for executing these observations.
GCN Circular #26149
D. Frederiks, on behalf of the Konus-Wind team:
Reported in Frederiks et al. 2019 (GCN Circ. 26126), the KW spectral parameters and fluxes of short/hard GRB 191031D are incorrect due to wrong instrument calibrations used. The correct values are given below.
As observed by Konus-Wind, the burst had a fluence of 5.72(-0.63,+0.69)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-0.016 s, of 4.12(-0.72,+0.80)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.12(-0.18,+0.20) and Ep = 735(-92,+112) keV (chi2 = 32/39 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.9 (chi2 =32/38 dof).
I apologize for possible inconvenience this may have caused.
GCN Circular #26150
Tom�s Ahumada (UMD), Shreya Anand (Caltech), Michael W. Coughlin (Caltech), S. Bradley Cenko (NASA GSFC), Eric C. Bellm (UW), Leo P. Singer (NASA GSFC), Mansi M. Kasliwal (Caltech) on behalf of the ZTF and GROWTH collaborations
We observed the localization region of the short GRB 191031D (trigger 594249816/191031891) detected by the Swift XRT, BAT and the Gamma-Ray Burst Monitor (GBM) on the Fermi satellite with the Palomar 48 inch telescope equipped with the 47 square degree Zwicky Transient Facility (ZTF) camera. These observations are part of the ZTF public survey and serendipitously covered the GRB localization. We obtained a series of g-band images beginning at 02:48:56.6 UT on 2019 Nov 01 (5.4 hours after the burst trigger time). This corresponds to ~68% of the probability enclosed in the GBM localization region and the totality of the Swift region.
The images were processed through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts. No high-significance transients were identified by our pipeline in the area observed.
The median 5 sigma upper limit for an isolated point source in our images was g > 20.8 mag for these observations.
ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266 <http://www.astronomerstelegram.org/?read=11266>), and includes IPAC; WIS, Israel; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; NRC, Taiwan; UW Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. Alert distribution service provided by DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system, supported by NSF PIRE grant 1545949.
GCN Circular #26175
A. Rouco Escorial, W. Fong, (Northwestern), E. Berger (Harvard), and R. Margutti (Northwestern) report:
"We initiated observations of the location of the short-duration GRB191031D (Fermi-GBM et al., GCN 26111; D'Elia et al., GCN 26112; Mailyan et al., GCN 26118) with the Chandra X-ray Observatory on 2019 Nov 3.694 UT (mid-time of 16:39:42 UT), 2.8 days post-burst under Program 20500021 (ObsID 21302; PI: Berger). The effective exposure time is 19.8 ksec.
We do not detect an X-ray source within the enhanced XRT position (Osborne et al., GCN 26117), and calculate a 3-sigma limit of <4.5e-4 cps in the 0.5-10 keV energy range using the method described by Gehrels (1986). Applying the best-fit XRT spectral parameters, we calculate an unabsorbed flux limit of <6.0e-15 erg/s/cm^2 in the 0.3-10 keV energy range.
Relative to the XRT light curve starting from t~900 sec post-burst, this constrains the late-time X-ray power-law decline to be alpha<-0.75 (where F~t^alpha).
We thank the Chandra staff for the rapid scheduling and execution of these observations."
GCN Circular #26240
Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
The short bright GRB 191031D (Swift detection: Ambrosi et al., GCN Circ. 26112, Sakamoto et al., GCN Circ. 26133; Fermi GBM detection: Mailyan and Meegan, GCN Circ. 26118; AGILE/MCAL observations: Ursi et al., GCN Circ. 26123; Konus-Wind observation: Frederiks et al., GCN Circ. 26126, 26149; AstroSat CZTI detection: Gaikwad et al., GCN Circ. 26129; https://gcn.gsfc.nasa.gov/other/191031D.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 21:23:31.261 UTC on 31 October 2019. The burst signal was seen by all CGBM detectors. No real-time CGBM GCN notice was distributed about this trigger because the real-time communication from the ISS was off (loss of signal).
The burst light curve shows a multi-peak structure which starts at T-0.168 sec, peaks at 0.008 sec and ends at T+0.192 sec. The T90 and T50 durations measured by the SGM data are 0.240 +- 0.079 sec and 0.104 +- 0.008 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1256592147/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #26841
P. D'Avanzo, S. Campana, M. G. Bernardini (INAF-OAB), M. Branchesi (GSSI), E. Chassande-Mottin (APC, CNRS/IN2P3), S. Covino (INAF-OAB), V. D'Elia (ASI-SSDC), G. Ghirlanda, G. Ghisellini, A. Melandri, L. Nava, O. S. Salafia (INAF-OAB), R. Salvaterra (INAF-IASFMi), G. Tagliaferri (INAF-OAB), S. D. Vergani (GEPI/Obs. Paris) report:
XMM-Newton started observing the field of the short GRB 191031D (Fermi-GBM et al., GCN Circ. 26111; D'Elia et al., GCN Circ. 26112; Mailyan et al., GCN Circ. 26118; Ursi et al., GCN Circ. 26123; Frederiks et al., GCN Circ. 26126; Gaikwad et al., GCN Circ. 26129; Frederiks et al., GCN Circ. 26149; Shimizu et al., GCN Circular. 26240) on 14 November 2019 at 09:58:00 UT, ~ 13.5 d after the burst. The last ~18 ks of the observation were affected by an enhanced background and were filtered out. The resulting EPIC/pn exposure time is 27.2 ks.
No X-ray source is detected within the enhanced XRT position (Osborne et al., GCN Circ. 26117) down to a 3sigma limit of ~ 1.6e-3 cts/s in the 0.3-10 keV energy range. Assuming the spectral parameters derived by Swift/XRT, the above value translates into an unabsorbed flux limit of ~ 4.8e-15 erg/cm^2/s in the 0.3-10 keV energy range.
We acknowledge the XMM-Newton staff for their support in scheduling and executing these observations.
photometric redshift z = 1.93 +0.22 -1.44
of host-galaxy: A. E. Nugent et al. 2022, ApJ, 940, 57
photometric redshift z= 0.5 +- 0.2
of host galaxy B. O'Connor et al. 2022, MN 515, 4890

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