Gamma-ray Burst 171001A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:27:22 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     775553,   Seg_Num: 0
GRB_RA:           22.088d {+01h 28m 21s} (J2000),
                  22.308d {+01h 29m 14s} (current),
                  21.470d {+01h 25m 53s} (1950)
GRB_DEC:         -11.893d {-11d 53' 35"} (J2000),
                 -11.802d {-11d 48' 05"} (current),
                 -12.152d {-12d 09' 06"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1440 [image_cnts]
TRIGGER_DUR:     88.000 [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:        18027 TJD;   274 DOY;   17/10/01
GRB_TIME:        66340.22 SOD {18:25:40.22} UT
GRB_PHI:          53.06 [deg]
GRB_THETA:        20.80 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.92 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -2  +0  +0 +93  +0 
SUN_POSTN:       188.05d {+12h 32m 13s}   -3.48d {-03d 28' 29"}
SUN_DIST:        159.16 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:      321.67d {+21h 26m 41s}  -14.63d {-14d 37' 34"}
MOON_DIST:        58.93 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.34,-72.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       15.74,-19.60 [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 = 90.13,-20.62 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:29:19 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.881d {-11d 52' 51"} (J2000)
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66533.93 SOD {18:28:53.93} UT,   193.7 [sec] since BAT Trigger Time
COUNTS:          3    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    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:     Sun 01 Oct 17 18:30:27 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     775553,   Seg_Num: 0
GRB_RA:           22.088d {+01h 28m 21s} (J2000),
                  22.308d {+01h 29m 14s} (current),
                  21.470d {+01h 25m 53s} (1950)
GRB_DEC:         -11.893d {-11d 53' 35"} (J2000),
                 -11.802d {-11d 48' 05"} (current),
                 -12.152d {-12d 09' 06"} (1950)
GRB_DATE:        18027 TJD;   274 DOY;   17/10/01
GRB_TIME:        66340.22 SOD {18:25:40.22} UT
TRIGGER_INDEX:   20000
GRB_PHI:          53.06 [deg]
GRB_THETA:        20.80 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     88.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.92 [sigma]
LC_URL:          sw00775553000msb.lc
SUN_POSTN:       188.06d {+12h 32m 13s}   -3.48d {-03d 28' 32"}
SUN_DIST:        159.16 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:      321.70d {+21h 26m 48s}  -14.62d {-14d 37' 13"}
MOON_DIST:        58.91 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.34,-72.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       15.74,-19.60 [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 = 90.13,-20.62 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:31:58 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.881d {-11d 52' 51"} (J2000)
POINT_ROLL:      136.910d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66537.99 SOD {18:28:57.99} UT,   197.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.244
N_STARS:         13
X_OFFSET:        620 [pixels]
Y_OFFSET:        373 [pixels]
X_MAX:           1579 [pixels]
Y_MAX:           1332 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00775553000msufc0197.fits
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 34"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.71d {+21h 26m 51s}  -14.62d {-14d 37' 02"}
MOON_DIST:        58.87 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:32:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.881d {-11d 52' 51"} (J2000)
POINT_ROLL:      136.910d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66537.99 SOD {18:28:57.99} UT,   197.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.244
N_STARS:         13
X_OFFSET:        620 [pixels]
Y_OFFSET:        373 [pixels]
X_MAX:           1579 [pixels]
Y_MAX:           1332 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00775553000msufc0197.fits
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 34"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.71d {+21h 26m 51s}  -14.62d {-14d 37' 00"}
MOON_DIST:        58.86 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:32:54 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     775553,   Seg_Num: 0
GRB_RA:           22.0773d {+01h 28m 18.55s} (J2000),
                  22.2969d {+01h 29m 11.25s} (current),
                  21.4588d {+01h 25m 50.10s} (1950)
GRB_DEC:         -11.8935d {-11d 53' 36.5"} (J2000),
                 -11.8020d {-11d 48' 07.1"} (current),
                 -12.1521d {-12d 09' 07.3"} (1950)
GRB_ERROR:       3.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66556.00 SOD {18:29:16.00} UT,   215.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 34"}
SUN_DIST:        159.17 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.72d {+21h 26m 53s}  -14.62d {-14d 36' 55"}
MOON_DIST:        58.87 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.31,-72.48 [deg] galactic lon,lat of the burst
ECL_COORDS:       15.73,-19.60 [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:     Sun 01 Oct 17 18:33:27 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.881d {-11d 52' 51"} (J2000)
ROLL:            136.910d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66537.99 SOD {18:28:57.99} UT,   197.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     528575357
X_OFFSET:        939 [pixels]
Y_OFFSET:        692 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1099
Y_GRB_POS:       852
BINNING_INDEX:   1
IM_URL:          sw00775553000msuni0217.fits
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 35"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.72d {+21h 26m 54s}  -14.61d {-14d 36' 51"}
MOON_DIST:        58.85 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [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:     Sun 01 Oct 17 18:33:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.881d {-11d 52' 51"} (J2000)
ROLL:            136.910d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66537.99 SOD {18:28:57.99} UT,   197.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     528575357
X_OFFSET:        939 [pixels]
Y_OFFSET:        692 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1099
Y_GRB_POS:       852
BINNING_INDEX:   1
IM_URL:          sw00775553000msuni0217.fits
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 35"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.73d {+21h 26m 54s}  -14.61d {-14d 36' 49"}
MOON_DIST:        58.85 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [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:     Sun 01 Oct 17 18:36:39 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
POINT_ROLL:      136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66696.18 SOD {18:31:36.18} UT,   356.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.630
N_STARS:         24
X_OFFSET:        380 [pixels]
Y_OFFSET:        133 [pixels]
X_MAX:           1819 [pixels]
Y_MAX:           1572 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00775553000msufc0355.fits
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 38"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.75d {+21h 27m 01s}  -14.61d {-14d 36' 28"}
MOON_DIST:        58.83 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:36:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
POINT_ROLL:      136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66696.18 SOD {18:31:36.18} UT,   356.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.630
N_STARS:         24
X_OFFSET:        380 [pixels]
Y_OFFSET:        133 [pixels]
X_MAX:           1819 [pixels]
Y_MAX:           1572 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00775553000msufc0355.fits
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 38"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.76d {+21h 27m 01s}  -14.61d {-14d 36' 26"}
MOON_DIST:        58.82 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:37:07 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     775553,   Seg_Num: 0
GRB_RA:           22.0774d {+01h 28m 18.57s} (J2000),
                  22.2970d {+01h 29m 11.28s} (current),
                  21.4589d {+01h 25m 50.12s} (1950)
GRB_DEC:         -11.8940d {-11d 53' 38.4"} (J2000),
                 -11.8025d {-11d 48' 08.9"} (current),
                 -12.1526d {-12d 09' 09.1"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66556.00 SOD {18:29:16.00} UT,   215.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       188.06d {+12h 32m 14s}   -3.48d {-03d 28' 39"}
SUN_DIST:        159.17 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.76d {+21h 27m 02s}  -14.61d {-14d 36' 25"}
MOON_DIST:        58.84 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.31,-72.48 [deg] galactic lon,lat of the burst
ECL_COORDS:       15.73,-19.60 [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:     Sun 01 Oct 17 18:38:01 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
ROLL:            136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66696.18 SOD {18:31:36.18} UT,   356.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     528575515
X_OFFSET:        939 [pixels]
Y_OFFSET:        692 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1099
Y_GRB_POS:       852
BINNING_INDEX:   1
IM_URL:          sw00775553000msuni0375.fits
SUN_POSTN:       188.06d {+12h 32m 15s}   -3.48d {-03d 28' 39"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.76d {+21h 27m 04s}  -14.61d {-14d 36' 18"}
MOON_DIST:        58.82 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [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:     Sun 01 Oct 17 18:38:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
ROLL:            136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  66696.18 SOD {18:31:36.18} UT,   356.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     528575515
X_OFFSET:        939 [pixels]
Y_OFFSET:        692 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1099
Y_GRB_POS:       852
BINNING_INDEX:   1
IM_URL:          sw00775553000msuni0375.fits
SUN_POSTN:       188.06d {+12h 32m 15s}   -3.48d {-03d 28' 40"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.77d {+21h 27m 04s}  -14.60d {-14d 36' 17"}
MOON_DIST:        58.81 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #21946
A. Y. Lien (GSFC/UMBC), P. D'Avanzo (INAF-OAB), J.D. Gropp (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), D. M. Palmer (LANL), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Swift Team:
At 18:25:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 171001A (trigger=775553). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 22.088, -11.893 which is
```
   RA(J2000) = 01h 28m 21s
   Dec(J2000) = -11d 53' 35"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 30 sec. The peak count rate was ~900 counts/sec (15-350 keV), at ~20 sec after the trigger.
The XRT began observing the field at 18:28:53.9 UT, 193.7 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 22.0774, -11.8940 which is equivalent to:
```
   RA(J2000)  = 01h 28m 18.59s
   Dec(J2000) = -11d 53' 38.5"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 37 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. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (3.56 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9 (+3.76/-3.10) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 197 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 0.03.
Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:43:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
POINT_ROLL:      136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  67202.22 SOD {18:40:02.22} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.165
N_STARS:         31
X_OFFSET:        380 [pixels]
Y_OFFSET:        133 [pixels]
X_MAX:           1819 [pixels]
Y_MAX:           1572 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00775553000msufc0861.fits
SUN_POSTN:       188.06d {+12h 32m 15s}   -3.48d {-03d 28' 44"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.81d {+21h 27m 15s}  -14.60d {-14d 35' 41"}
MOON_DIST:        58.77 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:43:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
POINT_ROLL:      136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  67202.22 SOD {18:40:02.22} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.165
N_STARS:         31
X_OFFSET:        380 [pixels]
Y_OFFSET:        133 [pixels]
X_MAX:           1819 [pixels]
Y_MAX:           1572 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00775553000msufc0861.fits
SUN_POSTN:       188.06d {+12h 32m 15s}   -3.48d {-03d 28' 45"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.81d {+21h 27m 15s}  -14.59d {-14d 35' 40"}
MOON_DIST:        58.77 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 01 Oct 17 18:44:36 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
ROLL:            136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  67202.22 SOD {18:40:02.22} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     528576021
X_OFFSET:        939 [pixels]
Y_OFFSET:        692 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1099
Y_GRB_POS:       852
BINNING_INDEX:   1
IM_URL:          sw00775553000msuni0881.fits
SUN_POSTN:       188.06d {+12h 32m 16s}   -3.48d {-03d 28' 46"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.82d {+21h 27m 17s}  -14.59d {-14d 35' 31"}
MOON_DIST:        58.76 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [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:     Sun 01 Oct 17 18:44:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     775553,   Seg_Num: 0
POINT_RA:         22.058d {+01h 28m 14s} (J2000)
POINT_DEC:       -11.880d {-11d 52' 48"} (J2000)
ROLL:            136.907d
IMG_START_DATE:  18027 TJD;   274 DOY;   17/10/01
IMG_START_TIME:  67202.22 SOD {18:40:02.22} UT,   862.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     528576021
X_OFFSET:        939 [pixels]
Y_OFFSET:        692 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1099
Y_GRB_POS:       852
BINNING_INDEX:   1
IM_URL:          sw00775553000msuni0881.fits
SUN_POSTN:       188.06d {+12h 32m 16s}   -3.48d {-03d 28' 46"}
SUN_DIST:        159.19 [deg]   Sun_angle= 11.1 [hr] (West of Sun)
MOON_POSTN:      321.82d {+21h 27m 18s}  -14.59d {-14d 35' 30"}
MOON_DIST:        58.76 [deg]
MOON_ILLUM:      83 [%]
GAL_COORDS:      154.24,-72.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       15.72,-19.58 [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 #21952
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1293 s of XRT Photon Counting mode data and 2 UVOT images for GRB 171001A, 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 = 22.07740, -11.89417 which is equivalent to:
```
RA (J2000): 01h 28m 18.58s
Dec (J2000): -11d 53' 39.0"
```
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 #21953
Martin Jelinek, Jan Strobl and Rene Hudec (ASU CAS Ondrejov)
We observed the field of the Swift GRB171001A (trigger #775553, Lien et al. GCNC 21946) with the 0.5m telescope of Ondrejov observatory, the obseration started at 21:17UT, i.e. about 2.9h after trigger and lasted for 30 miutes, when the field became observable. On a series of unfiltered exposures we do not detect any new object within or in the vicinity of the XRT errorbox (Evans et al., GCNC 21952) down to the USNO-B/R2 calibrated limit of R>20.0.
GCN Circular #21954
R. Itoh (Tokyo Tech), K. L. Murata (Tokyo Tech), K. Morihana (Nagoya U.) and T. Nagayama (Kagoshima U)
We observed the field of GRB 171001A (Lien et al., GCNCircular #21946) with the near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS attached to 1.4 m telescope IRSF (InfraRed Survey Facility) in Sutherland observatory, South Africa.
The observations started on 2017-10-01 19:16:51 UT. We detected the afterglow within the enhanced XRT error circle (Evans et al., GCN Circular #21952) in J band. The measured magnitudes (Vega magnitude system) were listed as below.
```
T0+[min]    MID-UT      T-EXP[sec]        J                 H
Ks
-------------------------------------------------------------------------------------------------
~48         19: 31              1270            17.0+-1.1      >16.3
>16.0
-------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
Given magnitudes were calibrated against 2MASS point sources in this field.
This observation was carried out by IRSF and OISTER collaboration.
GCN Circular #21955
N. P. M. Kuin (UCL-MSSL) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 171001A 198 s after the BAT trigger (Lien et al., GCN Circ. 21946). The source was found in the IR J band by Itoh et al. (GCN. Circ. # 21954). We find a source consistent with the XRT position (Evans et al. GCN Circ. 21952) in the initial UVOT exposures.
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              198         1359          373         21.23 +/- 0.30
v                  686         1409           58        >18.2
b                  612         1503           93        >19.8
u                  356          780          265        >20.3
w1                 736         1458           58        >20.4
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #21956
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU) and A.Y. Lien report on behalf of the Swift-XRT team:
We have analysed 6.0 ks of XRT data for GRB 171001A (Lien et al. GCN Circ. 21946), from 176 s to 52.2 ks after the BAT trigger. The data comprise 11 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 21952).
The light curve can be modelled with an initial rise, with a power-law index of alpha=-0.13 (+0.19, -0.21), followed by a break at T+1318 s to an alpha of 1.88 (+0.24, -0.18).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.09 (+0.21, -0.19). The best-fitting absorption column is 6.2 (+4.6, -2.7) x 10^20 cm^-2, consistent with the Galactic value of 3.6 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 3.1 x 10^-11 (3.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.2 (+4.6, -2.7) x 10^20 cm^-2
Galactic foreground: 3.6 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     2.09 (+0.21, -0.19)
```
If the light curve continues to decay with a power-law decay index of 1.88, the count rate at T+24 hours will be 2.1 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.6 x 10^-15 (7.8 x 10^-15) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00775553.
This circular is an official product of the Swift-XRT team.
GCN Circular #21957
H.J. Tan (CCU), H.X. Feng, D. Xu, Z.P. Zhu (NAOC), Y.D. Hu (IAA-CSIC), Y. Qin (Geneva Obs.), X. Gao (Urumqi No.1 Senior High School) report:
We observed the field of GRB 171001A (Lien et al., GCN 21946) using the 0.36m robotic telescope located at Nanshan, Xinjiang, China. Observations started at 18:37:21 UT on 2017-10-01, i.e, 701 sec after the BAT trigger, and all imaged were taken without filter.
The optical afterglow was detected at the XRT position (Evans et al., GCN 21952) with coordinates
```
R.A. (J2000) = 01:28:18.67
Dec. (J2000) = -11:53:39.0
```
with an uncertainty of ~0.5 arcsec.
Our photometry was summarized as follows:
```
========================================
Tmid(s)+T0   Exptime(s)       Mag(R)           MagErr

741                40*2            >17.60

902                60*2              17.93              0.13

1102              60*3              18.00              0.11

1328              90*2              18.55              0.11

1522              90*2              18.60              0.20

3327              90*8             >18.75
========================================
```
Note: (1) Photometry is calibrated with stars in the USNO B1 catalogue in the R-filter, although images were taken without filter. (2) MagErr is the only statistical error of the measurement. (3) The magnitudes are not corrected for the Galactic extinction.
GCN Circular #21958
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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 171001A (trigger #775553) (Lien et al., GCN Circ. 21946). The BAT ground-calculated position is RA, Dec = 22.080, -11.928 deg which is
```
  RA(J2000)  =  01h 28m 19.2s
  Dec(J2000) = -11d 55' 39.6"
```
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 72%.
The mask-weighted light curve shows a multi-peaked structure that starts at ~T+11 s and ends at ~T+37 s. The major peaks occur at ~T+13 s, ~T+17 s, and ~T+32 s, respectively. T90 (15-350 keV) is 22.8 +- 2.0 sec (estimated error including systematics).
The time-averaged spectrum from T+11.40 to T+37.02 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.48 +- 0.19. The fluence in the 15-150 keV band is 6.4 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+31.42 sec in the 15-150 keV band is 0.9 +- 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/775553/BA/
GCN Circular #21959
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m 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=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:
We observed the field of GRB 171001A (Lien, et al., GCN 21946) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2017/10 2.17 to 2017/10 2.51 UTC (9.63 to 17.69 hours after the BAT trigger), obtaining a total of 5.31 hours exposure in the r and i bands and 2.24 hours exposure in the Z, Y, J, and H bands.
We do not detect a source within the XRT error region (Evans, et al., GCN 21952) or at the position of the Nanshan optical transient (Tan, et al., GCN 21957). In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma):
```
 r > 24.15
 i > 23.98
 Z > 22.96
 Y > 22.77
 J > 22.43
 H > 22.03
```
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=F3mico Nacional in San Pedro M=E1rtir.

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Jochen Greiner, last update: 02-Oct-2017 [Disclaimer]