Gamma-ray Burst 161001A

(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:     Sat 01 Oct 16 01:05:31 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     714404,   Seg_Num: 0
GRB_RA:           71.913d {+04h 47m 39s} (J2000),
                  71.990d {+04h 47m 58s} (current),
                  71.685d {+04h 46m 44s} (1950)
GRB_DEC:         -57.283d {-57d 16' 57"} (J2000),
                 -57.254d {-57d 15' 13"} (current),
                 -57.370d {-57d 22' 10"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       373 [cnts]    Image_Peak=51 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10418     E_range: 25-100 keV
BKG_INTEN:       20040 [cnts]
BKG_TIME:        3903.05 SOD {01:05:03.05} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17662 TJD;   275 DOY;   16/10/01
GRB_TIME:        3916.49 SOD {01:05:16.49} UT
GRB_PHI:         129.37 [deg]
GRB_THETA:        17.92 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     16.21 [sigma]
IMAGE_SIGNIF:    7.36 [sigma]
MERIT_PARAMS:     +1  +0  +0  -4  +2  -3  +0  +0 +18  +0 
SUN_POSTN:       187.62d {+12h 30m 28s}   -3.29d {-03d 17' 18"}
SUN_DIST:        100.68 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      188.90d {+12h 35m 35s}   -1.28d {-01d 16' 39"}
MOON_DIST:       103.06 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       39.17,-77.50 [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 = 42.10,-20.09 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=496976720).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:05:40 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      47
TRIGGER_NUM:     496976720
GRB_RA:           70.183d {+04h 40m 44s} (J2000),
                  70.237d {+04h 40m 57s} (current),
                  70.025d {+04h 40m 06s} (1950)
GRB_DEC:         -61.450d {-61d 27' 00"} (J2000),
                 -61.418d {-61d 25' 05"} (current),
                 -61.545d {-61d 32' 40"} (1950)
GRB_ERROR:       12.40 [deg radius, statistical plus systematic]
GRB_INTEN:       216 [cnts/sec]
DATA_SIGNIF:     10.40 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        17662 TJD;   275 DOY;   16/10/01
GRB_TIME:        3916.72 SOD {01:05:16.72} UT
GRB_PHI:         321.00 [deg]
GRB_THETA:        40.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      1.08
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       1,0,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       187.62d {+12h 30m 28s}   -3.29d {-03d 17' 18"}
SUN_DIST:         99.75 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      188.90d {+12h 35m 36s}   -1.28d {-01d 16' 40"}
MOON_DIST:       102.11 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      271.73,-39.06 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       21.28,-79.99 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn161001045/quicklook/glg_lc_medres34_bn161001045.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 11.63,24.32 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=714404).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:05:55 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     496976720
GRB_RA:           84.560d {+05h 38m 14s} (J2000),
                  84.646d {+05h 38m 35s} (current),
                  84.305d {+05h 37m 13s} (1950)
GRB_DEC:         -54.250d {-54d 15' 00"} (J2000),
                 -54.241d {-54d 14' 27"} (current),
                 -54.277d {-54d 16' 36"} (1950)
GRB_ERROR:       6.52 [deg radius, statistical only]
DATA_SIGNIF:     27.70 [sigma]
DATA_INTERVAL:   0.512 [sec]
GRB_DATE:        17662 TJD;   275 DOY;   16/10/01
GRB_TIME:        3916.72 SOD {01:05:16.72} UT
GRB_PHI:         337.00 [deg]
GRB_THETA:        41.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       187.62d {+12h 30m 28s}   -3.29d {-03d 17' 18"}
SUN_DIST:         94.84 [deg]   Sun_angle= 6.9 [hr] (West of Sun)
MOON_POSTN:      188.90d {+12h 35m 36s}   -1.28d {-01d 16' 43"}
MOON_DIST:        97.22 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      261.96,-32.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       75.28,-77.41 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn161001045/quicklook/glg_lc_medres34_bn161001045.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_496976720.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
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.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=714404).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:05:50 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     496976720
GRB_RA:           70.267d {+04h 41m 04s} (J2000),
                  70.320d {+04h 41m 17s} (current),
                  70.108d {+04h 40m 26s} (1950)
GRB_DEC:         -61.433d {-61d 25' 59"} (J2000),
                 -61.402d {-61d 24' 06"} (current),
                 -61.528d {-61d 31' 39"} (1950)
GRB_ERROR:       5.73 [deg radius, statistical plus systematic]
GRB_INTEN:       789 [cnts/sec]
DATA_SIGNIF:     26.30 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        17662 TJD;   275 DOY;   16/10/01
GRB_TIME:        3916.72 SOD {01:05:16.72} UT
GRB_PHI:         321.00 [deg]
GRB_THETA:        40.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.56
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       1,0,0, 0,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       187.62d {+12h 30m 28s}   -3.29d {-03d 17' 18"}
SUN_DIST:         99.72 [deg]   Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN:      188.90d {+12h 35m 36s}   -1.28d {-01d 16' 42"}
MOON_DIST:       102.08 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      271.69,-39.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       21.50,-80.01 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn161001045/quicklook/glg_lc_medres34_bn161001045.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 11.63,24.32 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=714404).

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Sat 01 Oct 16 01:06:09 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    7582,   Sub_Num: 0
GRB_INTEN:      9.96 [sigma]   
GRB_TIME:       3916.71 SOD {01:05:16.71} UT
GRB_DATE:       17662 TJD;   275 DOY;   16/10/01
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=2.0000 and Time_Error=1.0000.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=496976720).
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2016-10/2016-10-01T01-05-16.6023-06521-43920-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:06:32 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.948d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.288d {-57d 17' 17"} (J2000)
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  3981.54 SOD {01:06:21.54} UT,   65.1 [sec] since BAT Trigger Time
COUNTS:          17    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:     Sat 01 Oct 16 01:09:09 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     714404,   Seg_Num: 0
GRB_RA:           71.913d {+04h 47m 39s} (J2000),
                  71.990d {+04h 47m 58s} (current),
                  71.685d {+04h 46m 44s} (1950)
GRB_DEC:         -57.283d {-57d 16' 57"} (J2000),
                 -57.254d {-57d 15' 13"} (current),
                 -57.370d {-57d 22' 10"} (1950)
GRB_DATE:        17662 TJD;   275 DOY;   16/10/01
GRB_TIME:        3916.68 SOD {01:05:16.68} UT
TRIGGER_INDEX:   10418
GRB_PHI:         129.37 [deg]
GRB_THETA:        17.92 [deg]
DELTA_TIME:      78.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     16.21 [sigma]
IMAGE_SIGNIF:    7.36 [sigma]
LC_URL:          sw00714404000msb.lc
SUN_POSTN:       187.62d {+12h 30m 29s}   -3.29d {-03d 17' 21"}
SUN_DIST:        100.68 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      188.93d {+12h 35m 42s}   -1.29d {-01d 17' 14"}
MOON_DIST:       103.07 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       39.17,-77.50 [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 = 42.10,-20.09 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:09:30 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.948d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.288d {-57d 17' 17"} (J2000)
POINT_ROLL:      113.693d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  3984.61 SOD {01:06:24.61} UT,   68.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.271
N_STARS:         39
X_OFFSET:        336 [pixels]
Y_OFFSET:        633 [pixels]
X_MAX:           1295 [pixels]
Y_MAX:           1592 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    4
SL_URL:          sw00714404000msufc0068.fits
SUN_POSTN:       187.62d {+12h 30m 29s}   -3.29d {-03d 17' 22"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      188.93d {+12h 35m 43s}   -1.29d {-01d 17' 17"}
MOON_DIST:       103.05 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:09:59 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.948d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.288d {-57d 17' 17"} (J2000)
POINT_ROLL:      113.693d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  3984.61 SOD {01:06:24.61} UT,   68.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.271
N_STARS:         39
X_OFFSET:        336 [pixels]
Y_OFFSET:        633 [pixels]
X_MAX:           1295 [pixels]
Y_MAX:           1592 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    4
SL_URL:          sw00714404000msufc0068.fits
SUN_POSTN:       187.62d {+12h 30m 29s}   -3.29d {-03d 17' 22"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      188.93d {+12h 35m 44s}   -1.29d {-01d 17' 22"}
MOON_DIST:       103.05 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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:     Sat 01 Oct 16 01:10:44 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.948d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.288d {-57d 17' 17"} (J2000)
ROLL:            113.693d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  3984.61 SOD {01:06:24.61} UT,   68.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     496976801
X_OFFSET:        655 [pixels]
Y_OFFSET:        952 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       815
Y_GRB_POS:       1112
BINNING_INDEX:   1
IM_URL:          sw00714404000msuni0085.fits
SUN_POSTN:       187.62d {+12h 30m 29s}   -3.29d {-03d 17' 23"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      188.94d {+12h 35m 45s}   -1.29d {-01d 17' 29"}
MOON_DIST:       103.05 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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:     Sat 01 Oct 16 01:11:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.948d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.288d {-57d 17' 17"} (J2000)
ROLL:            113.693d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  3984.61 SOD {01:06:24.61} UT,   68.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     496976801
X_OFFSET:        655 [pixels]
Y_OFFSET:        952 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       815
Y_GRB_POS:       1112
BINNING_INDEX:   1
IM_URL:          sw00714404000msuni0085.fits
SUN_POSTN:       187.62d {+12h 30m 29s}   -3.29d {-03d 17' 23"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      188.94d {+12h 35m 46s}   -1.29d {-01d 17' 33"}
MOON_DIST:       103.05 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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:     Sat 01 Oct 16 01:12:31 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     714404,   Seg_Num: 0
GRB_RA:           71.9184d {+04h 47m 40.41s} (J2000),
                  71.9952d {+04h 47m 58.84s} (current),
                  71.6899d {+04h 46m 45.58s} (1950)
GRB_DEC:         -57.2612d {-57d 15' 40.3"} (J2000),
                 -57.2323d {-57d 13' 56.3"} (current),
                 -57.3481d {-57d 20' 53.2"} (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:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4115.00 SOD {01:08:35.00} UT,   198.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       187.62d {+12h 30m 29s}   -3.29d {-03d 17' 24"}
SUN_DIST:        100.69 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      188.95d {+12h 35m 49s}   -1.30d {-01d 17' 47"}
MOON_DIST:       103.08 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.21,-39.13 [deg] galactic lon,lat of the burst
ECL_COORDS:       39.24,-77.48 [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 0.11% < P(seren) < 0.58%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:18:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.291d {-57d 17' 28"} (J2000)
POINT_ROLL:      113.691d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4197.20 SOD {01:09:57.20} UT,   280.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.447
N_STARS:         60
X_OFFSET:        96 [pixels]
Y_OFFSET:        393 [pixels]
X_MAX:           1535 [pixels]
Y_MAX:           1832 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00714404000msufc0280.fits
SUN_POSTN:       187.63d {+12h 30m 30s}   -3.29d {-03d 17' 30"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.00d {+12h 36m 00s}   -1.31d {-01d 18' 42"}
MOON_DIST:       103.06 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:19:14 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.291d {-57d 17' 28"} (J2000)
ROLL:            113.691d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4197.20 SOD {01:09:57.20} UT,   280.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     496977014
X_OFFSET:        655 [pixels]
Y_OFFSET:        952 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       815
Y_GRB_POS:       1112
BINNING_INDEX:   1
IM_URL:          sw00714404000msuni0297.fits
SUN_POSTN:       187.63d {+12h 30m 30s}   -3.29d {-03d 17' 31"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.01d {+12h 36m 02s}   -1.31d {-01d 18' 51"}
MOON_DIST:       103.06 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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:     Sat 01 Oct 16 01:19:50 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.291d {-57d 17' 28"} (J2000)
ROLL:            113.691d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4197.20 SOD {01:09:57.20} UT,   280.7 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     496977014
X_OFFSET:        655 [pixels]
Y_OFFSET:        952 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       815
Y_GRB_POS:       1112
BINNING_INDEX:   1
IM_URL:          sw00714404000msuni0297.fits
SUN_POSTN:       187.63d {+12h 30m 30s}   -3.29d {-03d 17' 32"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.01d {+12h 36m 03s}   -1.32d {-01d 18' 57"}
MOON_DIST:       103.06 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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 #19967
K. L. Page (U Leicester), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 01:05:16 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 161001A (trigger=714404). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 71.913, -57.283 which is
```
   RA(J2000) = 04h 47m 39s
   Dec(J2000) = -57d 16' 57"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 3 sec. The peak count rate was ~11000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 01:06:21.5 UT, 65.0 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 71.91848, -57.26127 which is equivalent to:
```
   RA(J2000)  = 04h 47m 40.44s
   Dec(J2000) = -57d 15' 40.6"
```
with an uncertainty of 3.9 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. We cannot determine whether the source is fading at the present time. No spectrum from the promptly downlinked event data is yet available to determine the column density.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 68 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 0.01.
Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). 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:     Sat 01 Oct 16 01:19:55 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.291d {-57d 17' 28"} (J2000)
POINT_ROLL:      113.691d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4197.20 SOD {01:09:57.20} UT,   280.7 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.447
N_STARS:         60
X_OFFSET:        96 [pixels]
Y_OFFSET:        393 [pixels]
X_MAX:           1535 [pixels]
Y_MAX:           1832 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    3
SL_URL:          sw00714404000msufc0280.fits
SUN_POSTN:       187.63d {+12h 30m 30s}   -3.29d {-03d 17' 32"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.01d {+12h 36m 03s}   -1.32d {-01d 18' 58"}
MOON_DIST:       103.06 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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:     Sat 01 Oct 16 01:19:30 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     714404,   Seg_Num: 0
GRB_RA:           71.9193d {+04h 47m 40.63s} (J2000),
                  71.9961d {+04h 47m 59.05s} (current),
                  71.6908d {+04h 46m 45.79s} (1950)
GRB_DEC:         -57.2608d {-57d 15' 38.8"} (J2000),
                 -57.2319d {-57d 13' 54.9"} (current),
                 -57.3477d {-57d 20' 51.8"} (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:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4115.00 SOD {01:08:35.00} UT,   198.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       187.63d {+12h 30m 30s}   -3.29d {-03d 17' 31"}
SUN_DIST:        100.69 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.01d {+12h 36m 02s}   -1.32d {-01d 18' 54"}
MOON_DIST:       103.09 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.21,-39.12 [deg] galactic lon,lat of the burst
ECL_COORDS:       39.24,-77.48 [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 0.11% < P(seren) < 0.58%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:25:49 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.292d {-57d 17' 29"} (J2000)
POINT_ROLL:      113.692d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4776.28 SOD {01:19:36.28} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.223
N_STARS:         67
X_OFFSET:        96 [pixels]
Y_OFFSET:        393 [pixels]
X_MAX:           1535 [pixels]
Y_MAX:           1832 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00714404000msufc0859.fits
SUN_POSTN:       187.63d {+12h 30m 31s}   -3.29d {-03d 17' 37"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.06d {+12h 36m 14s}   -1.33d {-01d 19' 55"}
MOON_DIST:       103.07 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 01 Oct 16 01:26:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.292d {-57d 17' 29"} (J2000)
POINT_ROLL:      113.692d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4776.28 SOD {01:19:36.28} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        4.223
N_STARS:         67
X_OFFSET:        96 [pixels]
Y_OFFSET:        393 [pixels]
X_MAX:           1535 [pixels]
Y_MAX:           1832 [pixels]
DET_THRESH:      17
PHOTO_THRESH:    10
SL_URL:          sw00714404000msufc0859.fits
SUN_POSTN:       187.63d {+12h 30m 31s}   -3.29d {-03d 17' 38"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.06d {+12h 36m 15s}   -1.33d {-01d 19' 57"}
MOON_DIST:       103.07 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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:     Sat 01 Oct 16 01:28:32 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.292d {-57d 17' 29"} (J2000)
ROLL:            113.692d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4776.28 SOD {01:19:36.28} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     496977593
X_OFFSET:        655 [pixels]
Y_OFFSET:        952 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       815
Y_GRB_POS:       1112
BINNING_INDEX:   1
IM_URL:          sw00714404000msuni0876.fits
SUN_POSTN:       187.63d {+12h 30m 32s}   -3.29d {-03d 17' 40"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.08d {+12h 36m 19s}   -1.34d {-01d 20' 21"}
MOON_DIST:       103.08 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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:     Sat 01 Oct 16 01:28:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     714404,   Seg_Num: 0
POINT_RA:         71.951d {+04h 47m 48s} (J2000)
POINT_DEC:       -57.292d {-57d 17' 29"} (J2000)
ROLL:            113.692d
IMG_START_DATE:  17662 TJD;   275 DOY;   16/10/01
IMG_START_TIME:  4776.28 SOD {01:19:36.28} UT,   859.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     496977593
X_OFFSET:        655 [pixels]
Y_OFFSET:        952 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       815
Y_GRB_POS:       1112
BINNING_INDEX:   1
IM_URL:          sw00714404000msuni0876.fits
SUN_POSTN:       187.63d {+12h 30m 32s}   -3.29d {-03d 17' 40"}
SUN_DIST:        100.66 [deg]   Sun_angle= 7.7 [hr] (West of Sun)
MOON_POSTN:      189.08d {+12h 36m 20s}   -1.34d {-01d 20' 24"}
MOON_DIST:       103.08 [deg]
MOON_ILLUM:      0 [%]
GAL_COORDS:      266.24,-39.10 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       39.23,-77.52 [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 #19968
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 161001A, we find an enhanced XRT position of the afterglow: RA, Dec: 71.9194, -57.2604 which is equivalent to:
```
   RA (J2000)  = 04 47 40.66
   Dec (J2000) = -57 15 37.3
```
with an uncertainty of 2.0 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/714404.
Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular #19969
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1075 s of XRT Photon Counting mode data and 2 UVOT images for GRB 161001A, 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 = 71.91991, -57.26095 which is equivalent to:
```
RA (J2000): 04h 47m 40.78s
Dec (J2000): -57d 15' 39.4"
```
with an uncertainty of 1.7 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 #19970
N. P. M. Kuin (UCL-MSSL) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 161001A 68 s after the BAT trigger (Page et al., GCN Circ. 19967). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 19969) 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            68          218          147         >20.8
u_FC               281          530          246         >20.2
white               68         1183          353         >20.4
v                  611         1232           78         >19.1
b                  536         1158           58         >19.1
u                  281         5994          395         >20.2
w1                 661         1282           78         >19.2
m2                 636         1257           78         >19.2
w2                1016         1208           39         >19.2
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #19971
T. Kruehler (MPE Garching), D. Xu (NAOC/CAS), J. Bolmer (MPE Garching and ESO Santiago), K. Wiersema (Univ. Leicester), D. Malesani (DARK/NBI and DTU Space), R. Sanchez-Ramirez (IAA-CSIC), J. P. U. Fynbo (DARK/NBI), report on behalf of a larger collaboration:
We observed the field of GRB 1601001A (Page et al., GCN 19967) with the ESO Very Large Telescope Unit 2 (Kueyen) equipped with the X-shooter spectrograph.
Close to, but outside, the enhanced XRT position (Osborne et al., GCN 19969), in our acquisition image we detect a bright, pointlike source at coordinates RA = 04:47:40.71, Dec = -57:15:36.8. This source is faintly visible in the archival DSS data and is pointlike in our images (0.75" seeing).
A spectrum was secured of this object, for a total of 4x600 s, starting on Oct 1.299 UT (6.1 hr after the GRB). The continuum is consistent with a stellar spectrum, and we conclude that this target is not associated with GRB 161001A.
Our slit, at a position angle of 319.6 deg (CCW from north), does however cover a portion of the XRT error circle. Within the wings of the the PSF of the DSS object, approximately 0.8 arcsec SE, we detect a number of emission lines which are consistent with [O II], Hbeta, [O III] and Halpha at a common redshift of z = 0.891, revealing the presence of a background object. While we cannot accurately determine its position from the slit information alone, that is consistent with being at the edge of the XRT error circle. Our images also hint a faint extension of the DSS object at a position consistent with that of the emission lines, which could represent the continuum emission of the object. As such, this is a candidate host galaxy of GRB 161001A.
We caution that we have no way to confirm the association between the emission line object and the GRB. No variability can be inferred from our data, and as we lack an estimate of the continuum flux, we can not presently quantify the chance association probability.
A finding chart showing the region surrounding the XRT position is shown at this URL: http://www.astro.ku.dk/~malesani/GRB/161001A/GRB161001A_slit.png
We acknowledge excellent support from the ESO observing staff at Paranal, in particular Zahed Wahhaj, Jonathan Smoker, and Claudia Cid.
GCN Circular #19972
A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester) and K.L. Page report on behalf of the Swift-XRT team:
We have analysed 6.9 ks of XRT data for GRB 161001A (Page et al. GCN Circ. 19967), from 51 s to 34.6 ks after the BAT trigger. The data comprise 128 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 19968).
The late-time light curve (from T0+5.8 ks) can be modelled with a power-law decay with a decay index of alpha=1.40 (+0.17, -0.16).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.07 (+0.16, -0.15). The best-fitting absorption column is 4.9 (+0.9, -0.8) x 10^21 cm^-2, in excess of the Galactic value of 1.1 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.90 (+/-0.16) and a best-fitting absorption column of 6.5 (+1.2, -1.1) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.6 x 10^-11 (7.4 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.5 (+1.2, -1.1) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^20 cm^-2
Excess significance: 9.7 sigma
Photon index:	     1.90 (+/-0.16)
```
If the light curve continues to decay with a power-law decay index of 1.40, the count rate at T+24 hours will be 5.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.5 x 10^-13 (4.0 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/00714404.
This circular is an official product of the Swift-XRT team.
GCN Circular #19973
P Veres, M Stanbro and C Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 01:05:16.72 UT on 01 October 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 161001A (trigger 496976720 / 161001045) which was also detected by the Swift/BAT (Page et al., GCN 19967). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 37 degrees.
The GBM light curve consists of a dominant pulse preceded by weaker emission with a duration (T90) of about 2.2 s (50-300 keV). The time-averaged spectrum from T0-1.1 s to T0+2.9 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.89 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 313 +/- 54 keV.
The event fluence (10-1000 keV) in this time interval is (2.3 +/- 0.2)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.2 s in the 10-1000 keV band is 6.9 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #19974
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), J. P. Norris (BSU), K. L. Page (U Leicester) D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-274 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 161001A (trigger #714404) (Page, et al. GCN Circ. 19967). The BAT ground-calculated position is RA, Dec = 71.923, -57.261 deg which is
```
  RA(J2000)  =  04h 47m 41.5s
  Dec(J2000) = -57d 15' 39.8"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 78%.
The mask-weighted light curve shows several overlapping pulses that stars at ~T-0.3, and ends at ~T+3 s. The highest peak occurs at ~ T+1.6 s. T90 (15-350 keV) is 2.6 +- 0.4 sec (estimated error including systematics).
The time-averaged spectrum from T-0.2 to T+3.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.14 +- 0.09. The fluence in the 15-150 keV band is 6.7 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.40 sec in the 15-150 keV band is 3.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
Using a 16-ms binned light curve, the lag analysis finds a lag of 7 (+/- 13) ms for the 100-350 keV to 25-50 keV band, and -7.5 (+26, -19) ms for the 50-100 keV to 15-25 keV band, which is consistent with those of a short GRB.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/714404/BA/
GCN Circular #19975
T.-W. Chen (MPE Garching), S. Klose, A. Nicuesa Guelbenzu (TLS), J. Bolmer (MPE Garching and ESO Vitacura), T. Kruehler and J. Greiner (both MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 161001A (Swift trigger 714404; Page et al., GCN #19967) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO La Silla Observatory (Chile).
Observations started at 02:48 UT on 2016-10-01, 1.71 hours after the GRB trigger. They were performed at an average seeing of 2" and at an average airmass of 2.3.
We found a faint singular point source which is south-west 2.2 arcsec away from the photometric center of nearby bright DSS2 object for which Kruehler et al. (GCN #19971) reported X-Shooter spectroscopy. The position is within the 2.3" Swift-XRT error circle reported by Evans et al. (GCN #19968) and also within the 1.9" enhanced XRT position (Osborne et al., GCN 19969), at RA (J2000.0) = 04 h 47 m 40.57 s DEC (J2000.0) = -57d 15' 39.2 with an uncertainty of 0.5" in each coordinate.
Based on images with 36 min of total exposure in g'r'i'z' and 30 min in JHK at a mid-time of 03:58 UT on 2016-10-01, we derive the following preliminary magnitudes and upper limits (all in the AB system):
```
g' = 23.1 +- 0.2 mag,
r' = 22.5 +- 0.1 mag,
i' = 21.6 +- 0.1 mag,
z' = 21.5 +- 0.1 mag,
J > 21.3 mag,
H > 20.3 mag, and
K > 18.7 mag.
```
Second-epoch observations were performed at a mean time of 09:19 UT at an average seeing 1.1" and at an average airmass of 1.1. At that time the source seems to have faded to:
r' = 22.9 +- 0.1 mag
Given magnitudes are calibrated against USNO as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.01 mag in the direction of the burst (Schlafly & Finkbeiner 2011).
GCN Circular #19976
R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA)
H. Levato, C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
D.Buckley, S. Potter, South African Astronomical Observatory
E.Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, O.Gress, P.Balanutsa, A.Kuznetsov, D.Kuvshinov Lomonosov Moscow State University, Sternberg Astronomical Institute
R. Rebolo, M. Serra Ricart, N. Lodieu, G. Israelian The Instituto de Astrofisica de Canarias
K.Ivanov, J.Rabinovich, N.M.Budnev, Irkutsk State University
A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk
MASTER-OAFA robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in OAFA was pointed to the GRB161001A 29 sec after notice time and 41 sec after trigger time at 2016-10-01 01:05:57UT. On our first (10s exposure) set we not found OT within 6 square degrees field around SWIFT BAT error-box (Page et al., GCN 19967; Markwardt et al.,GCN 19974 ) brighter then 16.7 unfiltered magnitude.
MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB161001A 167 sec after notice time and 176 sec after trigger time at 2016-10-01 01:08:17 UT. On our first (40s exposure) set we haven`t found optical transient within SWIFT error-box.
The 5-sigma upper limit has been about 18.4 mag
We found optical object at first hour coadded images by both MASTERs telescopes at coordinates Ra 04:47:40.83 Dec -57:15:38.07 (+-0.7 arcsec error) with unfiltered magnitude:
0.8R +0.2B = 20.6 (+0.1 -0.4)
with respect to USNO B stars. We have archival images in MASTER SAAO DataBase at 2016-04-09 with 20.9 3-SIGMA limit. We see same object at same position.
We note that our scale is 1 pix ~ 2 arcsec . So the DSS2 object (Kruehler et al., GCN 19971) and GROND afterglow candidate (Chen et al., GCN 19975) are inside the our pixel.
The message may be cited.
GCN Circular #19977
D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline, on behalf of the Konus-Wind team, report:
GRB 161001A (Swift/BAT detection: Page et al., GCN 19967; Fermi GBM observation: Veres et al., GCN 19973) triggered Konus-Wind at T0=3D3919.479 s UT (01:05:19.479).
The light curve shows a short pulse with a total duration of ~0.5 s. The emission is seen up to ~5 MeV.
As observed by Konus-Wind, the burst had a fluence of (1.8 =B1 0.5)x10^-6 erg/cm2 and a 16-ms peak energy flux, measured from T0-0.016, of (8.0 =B1 3.5)x10^-6 erg/cm2 (both in the 20 keV - 10 MeV energy range).
The spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 10 MeV range by a cutoff power-law (CPL) function with the following model parameters: the photon index alpha =3D -0.46(-0.36,+0.48), and the peak energy Ep =3D 437(-117,+190) keV, chi2 =3D 30.0/36 dof. Fitting this spectrum with the GRB (Band) function yields the same alpha and Ep with only an upper limit on beta of -2.1, chi2 =3D 30.0/35 dof.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB161001_T03919/
All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.
GCN Circular #19999
K. L. Murata (Nagoya University), K. Miyakawa (Tokyo Institute of Technology), and T. Nagayama (Kagoshima University)
We observed the field of GRB 161001A ( Page et al., GCN Circular #19967) 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 2016-10-01 02:41:46 UT (~ 95 min. after the burst). We could not detect the afterglow within the enhanced XRT error circle (Osborne et al., GCN Circular #19969) in the three bands. We have obtained the following preliminary upper limits (Vega magnitude system):
```
 J > 14.61
 H > 14.19
 Ks > 14.01
```
Given magnitudes were calibrated against 2MASS point sources in this field. The upper limits were determined as the magnitudes of the fainter star within 1 arcmin from the enhanced XRT position.
This observation was carried out by IRSF and OISTER collaboration.
photometric redshift z = 0.67 ± 0.02
of host-galaxy: A. E. Nugent et al. 2022, ApJ, 940, 57

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