Gamma-ray Burst 191017B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 17 Oct 19 14:36:37 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     929981,   Seg_Num: 0
GRB_RA:          245.151d {+16h 20m 36s} (J2000),
                 245.745d {+16h 22m 59s} (current),
                 243.663d {+16h 14m 39s} (1950)
GRB_DEC:         -73.561d {-73d 33' 40"} (J2000),
                 -73.607d {-73d 36' 25"} (current),
                 -73.441d {-73d 26' 27"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       9275 [cnts]    Image_Peak=261 [image_cnts]
TRIGGER_DUR:     2.048 [sec] 
TRIGGER_INDEX:   256     E_range: 15-50 keV
BKG_INTEN:       99269 [cnts]
BKG_TIME:        52536.23 SOD {14:35:36.23} UT
BKG_DUR:         24 [sec]
GRB_DATE:        18773 TJD;   290 DOY;   19/10/17
GRB_TIME:        52566.89 SOD {14:36:06.89} UT
GRB_PHI:          21.87 [deg]
GRB_THETA:        38.28 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.39 [sigma]
IMAGE_SIGNIF:    8.63 [sigma]
MERIT_PARAMS:     +1  +0  +0  +1  +1  -1  +0  +0 -35  +0 
SUN_POSTN:       202.16d {+13h 28m 38s}   -9.29d {-09d 17' 07"}
SUN_DIST:         69.11 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.14d {+04h 20m 33s}  +18.51d {+18d 30' 31"}
MOON_DIST:       124.90 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.46 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      259.09,-51.06 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 355.54,-16.20 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 17 Oct 19 14:38:00 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.071d {+16h 20m 17s} (J2000)
POINT_DEC:       -73.537d {-73d 32' 13"} (J2000)
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  52670.74 SOD {14:37:50.74} UT,   103.8 [sec] since BAT Trigger Time
COUNTS:          11    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 17 Oct 19 14:40:29 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     929981,   Seg_Num: 0
GRB_RA:          245.151d {+16h 20m 36s} (J2000),
                 245.745d {+16h 22m 59s} (current),
                 243.663d {+16h 14m 39s} (1950)
GRB_DEC:         -73.561d {-73d 33' 40"} (J2000),
                 -73.607d {-73d 36' 25"} (current),
                 -73.441d {-73d 26' 27"} (1950)
GRB_DATE:        18773 TJD;   290 DOY;   19/10/17
GRB_TIME:        52566.89 SOD {14:36:06.89} UT
TRIGGER_INDEX:   256
GRB_PHI:          21.87 [deg]
GRB_THETA:        38.28 [deg]
DELTA_TIME:      -24.00 [sec]
TRIGGER_DUR:     2.048 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.39 [sigma]
IMAGE_SIGNIF:    8.63 [sigma]
LC_URL:          sw00929981000msb.lc
SUN_POSTN:       202.16d {+13h 28m 39s}   -9.29d {-09d 17' 10"}
SUN_DIST:         69.11 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.17d {+04h 20m 41s}  +18.52d {+18d 31' 00"}
MOON_DIST:       124.91 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.46 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      259.09,-51.06 [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 = 355.54,-16.20 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 17 Oct 19 14:43:56 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     929981,   Seg_Num: 0
GRB_RA:          245.1249d {+16h 20m 29.97s} (J2000),
                 245.7182d {+16h 22m 52.36s} (current),
                 243.6380d {+16h 14m 33.11s} (1950)
GRB_DEC:         -73.5407d {-73d 32' 26.5"} (J2000),
                 -73.5865d {-73d 35' 11.5"} (current),
                 -73.4203d {-73d 25' 13.0"} (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:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  52823.00 SOD {14:40:23.00} UT,   256.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       202.16d {+13h 28m 39s}   -9.29d {-09d 17' 14"}
SUN_DIST:         69.09 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.20d {+04h 20m 48s}  +18.52d {+18d 31' 26"}
MOON_DIST:       124.94 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.44,-16.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      259.07,-51.04 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 17 Oct 19 14:45:05 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.064d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
POINT_ROLL:      313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  52868.11 SOD {14:41:08.11} UT,   301.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.962
N_STARS:         190
X_OFFSET:        261 [pixels]
Y_OFFSET:        675 [pixels]
X_MAX:           1220 [pixels]
Y_MAX:           1634 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00929981000msufc0301.fits
SUN_POSTN:       202.16d {+13h 28m 40s}   -9.29d {-09d 17' 15"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.21d {+04h 20m 51s}  +18.53d {+18d 31' 35"}
MOON_DIST:       124.94 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 17 Oct 19 14:45:23 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.064d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
POINT_ROLL:      313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  52868.11 SOD {14:41:08.11} UT,   301.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.962
N_STARS:         190
X_OFFSET:        261 [pixels]
Y_OFFSET:        675 [pixels]
X_MAX:           1220 [pixels]
Y_MAX:           1634 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00929981000msufc0301.fits
SUN_POSTN:       202.16d {+13h 28m 40s}   -9.29d {-09d 17' 15"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.21d {+04h 20m 52s}  +18.53d {+18d 31' 37"}
MOON_DIST:       124.94 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [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 17 Oct 19 14:45:31 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     929981,   Seg_Num: 0
GRB_RA:          245.1262d {+16h 20m 30.28s} (J2000),
                 245.7195d {+16h 22m 52.67s} (current),
                 243.6393d {+16h 14m 33.42s} (1950)
GRB_DEC:         -73.5408d {-73d 32' 26.8"} (J2000),
                 -73.5866d {-73d 35' 11.8"} (current),
                 -73.4204d {-73d 25' 13.4"} (1950)
GRB_ERROR:       2.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  52823.00 SOD {14:40:23.00} UT,   256.1 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       202.16d {+13h 28m 40s}   -9.29d {-09d 17' 15"}
SUN_DIST:         69.09 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.22d {+04h 20m 52s}  +18.53d {+18d 31' 38"}
MOON_DIST:       124.94 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.44,-16.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      259.07,-51.04 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 17 Oct 19 14:46:42 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.064d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
ROLL:            313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  52868.11 SOD {14:41:08.11} UT,   301.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     593016091
X_OFFSET:        581 [pixels]
Y_OFFSET:        995 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       741
Y_GRB_POS:       1155
BINNING_INDEX:   1
IM_URL:          sw00929981000msuni0325.fits
SUN_POSTN:       202.17d {+13h 28m 40s}   -9.29d {-09d 17' 16"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.23d {+04h 20m 54s}  +18.53d {+18d 31' 47"}
MOON_DIST:       124.95 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [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 17 Oct 19 14:46:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.064d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
ROLL:            313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  52868.11 SOD {14:41:08.11} UT,   301.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     593016091
X_OFFSET:        581 [pixels]
Y_OFFSET:        995 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       741
Y_GRB_POS:       1155
BINNING_INDEX:   1
IM_URL:          sw00929981000msuni0325.fits
SUN_POSTN:       202.17d {+13h 28m 40s}   -9.29d {-09d 17' 16"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.23d {+04h 20m 55s}  +18.53d {+18d 31' 49"}
MOON_DIST:       124.95 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [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 17 Oct 19 14:55:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.063d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
POINT_ROLL:      313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  53425.88 SOD {14:50:25.88} UT,   859.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.070
N_STARS:         190
X_OFFSET:        21 [pixels]
Y_OFFSET:        435 [pixels]
X_MAX:           1460 [pixels]
Y_MAX:           1874 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00929981000msufc0858.fits
SUN_POSTN:       202.17d {+13h 28m 41s}   -9.29d {-09d 17' 24"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.31d {+04h 21m 14s}  +18.55d {+18d 32' 57"}
MOON_DIST:       124.96 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 17 Oct 19 14:56:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.063d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
POINT_ROLL:      313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  53425.88 SOD {14:50:25.88} UT,   859.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.070
N_STARS:         190
X_OFFSET:        21 [pixels]
Y_OFFSET:        435 [pixels]
X_MAX:           1460 [pixels]
Y_MAX:           1874 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    8
SL_URL:          sw00929981000msufc0858.fits
SUN_POSTN:       202.17d {+13h 28m 41s}   -9.29d {-09d 17' 25"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.31d {+04h 21m 15s}  +18.55d {+18d 32' 59"}
MOON_DIST:       124.97 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [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 17 Oct 19 14:57:18 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.063d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
ROLL:            313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  53425.88 SOD {14:50:25.88} UT,   859.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     593016649
X_OFFSET:        581 [pixels]
Y_OFFSET:        995 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       741
Y_GRB_POS:       1155
BINNING_INDEX:   1
IM_URL:          sw00929981000msuni0882.fits
SUN_POSTN:       202.17d {+13h 28m 41s}   -9.29d {-09d 17' 26"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.32d {+04h 21m 17s}  +18.55d {+18d 33' 07"}
MOON_DIST:       124.97 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [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 17 Oct 19 14:57:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     929981,   Seg_Num: 0
POINT_RA:        245.063d {+16h 20m 15s} (J2000)
POINT_DEC:       -73.538d {-73d 32' 16"} (J2000)
ROLL:            313.984d
IMG_START_DATE:  18773 TJD;   290 DOY;   19/10/17
IMG_START_TIME:  53425.88 SOD {14:50:25.88} UT,   859.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     593016649
X_OFFSET:        581 [pixels]
Y_OFFSET:        995 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       741
Y_GRB_POS:       1155
BINNING_INDEX:   1
IM_URL:          sw00929981000msuni0882.fits
SUN_POSTN:       202.17d {+13h 28m 41s}   -9.29d {-09d 17' 26"}
SUN_DIST:         69.07 [deg]   Sun_angle= -2.9 [hr] (East of Sun)
MOON_POSTN:       65.32d {+04h 21m 18s}  +18.55d {+18d 33' 08"}
MOON_DIST:       124.97 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      316.43,-16.42 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      259.04,-51.05 [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 #26021
B. Sbarufatti (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), M. J. Moss (GWU), K. L. Page (U Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
At 14:36:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191017B (trigger=929981). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 245.151, -73.561 which is
```
   RA(J2000) = 16h 20m 36s
   Dec(J2000) = -73d 33' 40"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 8 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 14:37:50.7 UT, 103.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 245.1255, -73.5404 which is equivalent to:
```
   RA(J2000)  = 16h 20m 30.13s
   Dec(J2000) = -73d 32' 25.3"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 78 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (9.84 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3 (+3.00/-2.59) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 301 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 0.11.
Burst Advocate for this burst is B. Sbarufatti (bxs60 AT psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular #26022
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 759 s of XRT Photon Counting mode data and 2 UVOT images for GRB 191017B, 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 = 245.12493, -73.54074 which is equivalent to:
```
RA (J2000): 16h 20m 29.98s
Dec (J2000): -73d 32' 26.7"
```
with an uncertainty of 1.8 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 #26027
A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU), J. D. Gropp (PSU), A. Tohuvavohu (U. Toronto), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester) and B. Sbarufatti report on behalf of the Swift-XRT team:
We have analysed 6.1 ks of XRT data for GRB 191017B (Sbarufatti et al. GCN Circ. 26021), from 256 s to 29.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 26022).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.64 (+/-0.05).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.54 (+0.20, -0.12). The best-fitting absorption column is consistent with the Galactic value of 9.8 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 4.4 x 10^-11 (4.9 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     9.8 (+/-6.9) x 10^20 cm^-2
Galactic foreground: 9.8 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.54 (+0.20, -0.12)
```
If the light curve continues to decay with a power-law decay index of 0.64, the count rate at T+24 hours will be 0.018 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.8 x 10^-13 (8.6 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00929981.
This circular is an official product of the Swift-XRT team.
GCN Circular #26029
GRB 191017B: Swift/UVOT Upper Limits
J. D. Gropp (PSU) and B. Sbarufatti (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 191017B 302 s after the BAT trigger (Sbarufatti et al., GCN Circ. 26021). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 26022) 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           302          452          147         >18.9
white              302         1010          334         >19.1
v                  460         4806          255         >18.1
b                  558          752           39         >18.3
u                  533          727           39         >18.9
w1                 509          702           39         >18.2
m2                 484          852           39         >18.6
w2                 609         4601          235         >20.0
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.11 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #26030
J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), (i.e. the Swift-BAT team):
Using the data set from T-82 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 191017B (trigger #929981) (Sbarufatti et al., GCN Circ. 26021). The BAT ground-calculated position is RA, Dec = 245.131, -73.583 deg which is
```
   RA(J2000)  =  16h 20m 31.3s
   Dec(J2000) = -73d 34' 57.7"
```
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 44%.
The mask weighted light curve shows a single peak structure with a duration of ~8 sec. The overall structure starts at ~ T-2 sec and lasts till ~ T+6 sec. T90 (15-350 keV) is 5.95 +- 1.28 sec (estimated error including systematics).
The time-averaged spectrum from T-1.34 to T+5.59 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.82 +- 0.20. The fluence in the 15-150 keV band is 5.6 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.36 sec in the 15-150 keV band is 1.9 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/929981/BA/

Back to JG's homepage

Jochen Greiner, last update: 19-Oct-2019 [Disclaimer]