Gamma-ray Burst 160131A

(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 31 Jan 16 08:22:46 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     672236,   Seg_Num: 0
GRB_RA:           78.182d {+05h 12m 44s} (J2000),
                  78.377d {+05h 13m 30s} (current),
                  77.575d {+05h 10m 18s} (1950)
GRB_DEC:          -7.067d {-07d 04' 02"} (J2000),
                  -7.049d {-07d 02' 57"} (current),
                  -7.126d {-07d 07' 32"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2840 [cnts]    Image_Peak=134 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       17546 [cnts]
BKG_TIME:        30016.22 SOD {08:20:16.22} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17418 TJD;    31 DOY;   16/01/31
GRB_TIME:        30031.96 SOD {08:20:31.96} UT
GRB_PHI:         -93.02 [deg]
GRB_THETA:        23.77 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     11.66 [sigma]
IMAGE_SIGNIF:    7.32 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -3  +0  +0 +50  +0 
SUN_POSTN:       313.34d {+20h 53m 21s}  -17.50d {-17d 29' 58"}
SUN_DIST:        120.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.12d {+14h 04m 29s}   -9.08d {-09d 04' 32"}
MOON_DIST:       130.23 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.14 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       76.43,-29.95 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 179.52,8.55 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(5.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=7353).

red DSS finding chart ps-file

GCN NOTICE

 
TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Sun 31 Jan 16 08:21:51 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    7353,   Sub_Num: 0
GRB_INTEN:      9.02 [sigma]   
GRB_TIME:       30036.92 SOD {08:20:36.92} UT
GRB_DATE:       17418 TJD;    31 DOY;   16/01/31
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=2.0000 and Time_Error=1.0000. 
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2016-01/2016-01-31T08-20-36.7733-03088-15248-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:23:31 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     672236,   Seg_Num: 0
GRB_RA:           78.1700d {+05h 12m 40.80s} (J2000),
                  78.3652d {+05h 13m 27.65s} (current),
                  77.5633d {+05h 10m 15.18s} (1950)
GRB_DEC:          -7.0489d {-07d 02' 56.0"} (J2000),
                  -7.0307d {-07d 01' 50.4"} (current),
                  -7.1074d {-07d 06' 26.7"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.29e-08 [erg/cm2/sec]
GRB_SIGNIF:      16.21 [sigma]
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30101.68 SOD {08:21:41.68} UT,   69.7 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.22 261.68 243.63
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       313.34d {+20h 53m 21s}  -17.50d {-17d 29' 58"}
SUN_DIST:        120.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.13d {+14h 04m 31s}   -9.08d {-09d 04' 38"}
MOON_DIST:       130.25 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.87,-25.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       76.42,-29.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.31 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:23:41 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     672236,   Seg_Num: 0
GRB_RA:           78.1700d {+05h 12m 40.8s} (J2000),
                  78.3652d {+05h 13m 27.6s} (current),
                  77.5633d {+05h 10m 15.1s} (1950)
GRB_DEC:          -7.0489d {-07d 02' 56.0"} (J2000),
                  -7.0307d {-07d 01' 50.4"} (current),
                  -7.1074d {-07d 06' 26.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       263 [cnts]
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30101.68 SOD {08:21:41.68} UT,   69.7 [sec] since BAT Trigger Time
CENTROID_X:      259.21,  raw= 259  [pixels]
CENTROID_Y:      263.71,  raw= 264  [pixels]
ROLL:            244.96 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -80.35
GRB_POS_XRT_Z:   -108.62
IMAGE_URL:       sw00672236000msxps_rw.img
SUN_POSTN:       313.34d {+20h 53m 21s}  -17.50d {-17d 29' 58"}
SUN_DIST:        120.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.13d {+14h 04m 31s}   -9.08d {-09d 04' 39"}
MOON_DIST:       130.25 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.87,-25.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       76.42,-29.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:23:47 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     672236,   Seg_Num: 0
GRB_RA:           78.1700d {+05h 12m 40.8s} (J2000),
                  78.3652d {+05h 13m 27.6s} (current),
                  77.5633d {+05h 10m 15.1s} (1950)
GRB_DEC:          -7.0489d {-07d 02' 56.0"} (J2000),
                  -7.0307d {-07d 01' 50.4"} (current),
                  -7.1074d {-07d 06' 26.7"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       263 [cnts]
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30101.68 SOD {08:21:41.68} UT,   69.7 [sec] since BAT Trigger Time
CENTROID_X:      259.21,  raw= 259  [pixels]
CENTROID_Y:      263.71,  raw= 264  [pixels]
ROLL:            244.96 [deg]
GAIN:            4
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -80.35
GRB_POS_XRT_Z:   -108.62
IMAGE_URL:       sw00672236000msxps_rw.img
SUN_POSTN:       313.34d {+20h 53m 21s}  -17.50d {-17d 29' 58"}
SUN_DIST:        120.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.13d {+14h 04m 31s}   -9.08d {-09d 04' 40"}
MOON_DIST:       130.25 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.87,-25.14 [deg] galactic lon,lat of the burst
ECL_COORDS:       76.42,-29.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:24:35 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     672236,   Seg_Num: 0
GRB_RA:           78.182d {+05h 12m 44s} (J2000),
                  78.377d {+05h 13m 30s} (current),
                  77.575d {+05h 10m 18s} (1950)
GRB_DEC:          -7.067d {-07d 04' 02"} (J2000),
                  -7.049d {-07d 02' 57"} (current),
                  -7.126d {-07d 07' 32"} (1950)
GRB_DATE:        17418 TJD;    31 DOY;   16/01/31
GRB_TIME:        30031.96 SOD {08:20:31.96} UT
TRIGGER_INDEX:   146
GRB_PHI:         -93.02 [deg]
GRB_THETA:        23.77 [deg]
DELTA_TIME:      26.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.66 [sigma]
IMAGE_SIGNIF:    7.32 [sigma]
LC_URL:          sw00672236000msb.lc
SUN_POSTN:       313.34d {+20h 53m 22s}  -17.50d {-17d 29' 57"}
SUN_DIST:        120.43 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.14d {+14h 04m 33s}   -9.08d {-09d 04' 47"}
MOON_DIST:       130.24 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.14 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       76.43,-29.95 [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 = 179.52,8.55 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:25:33 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.207d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.056d {-07d 03' 22"} (J2000)
POINT_ROLL:      244.960d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30110.49 SOD {08:21:50.49} UT,   78.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.322
N_STARS:         49
X_OFFSET:        672 [pixels]
Y_OFFSET:        456 [pixels]
X_MAX:           1631 [pixels]
Y_MAX:           1415 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    6
SL_URL:          sw00672236000msufc0078.fits
SUN_POSTN:       313.34d {+20h 53m 22s}  -17.50d {-17d 29' 56"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.14d {+14h 04m 35s}   -9.08d {-09d 04' 54"}
MOON_DIST:       130.23 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.46,-29.94 [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 31 Jan 16 08:25:06 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.207d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.056d {-07d 03' 22"} (J2000)
POINT_ROLL:      244.960d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30110.49 SOD {08:21:50.49} UT,   78.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.322
N_STARS:         49
X_OFFSET:        672 [pixels]
Y_OFFSET:        456 [pixels]
X_MAX:           1631 [pixels]
Y_MAX:           1415 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    6
SL_URL:          sw00672236000msufc0078.fits
SUN_POSTN:       313.34d {+20h 53m 22s}  -17.50d {-17d 29' 57"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.14d {+14h 04m 34s}   -9.08d {-09d 04' 51"}
MOON_DIST:       130.22 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.46,-29.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:26:40 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.207d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.056d {-07d 03' 22"} (J2000)
ROLL:            244.960d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30110.49 SOD {08:21:50.49} UT,   78.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     475921326
X_OFFSET:        1077 [pixels]
Y_OFFSET:        901 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1237
Y_GRB_POS:       1061
BINNING_INDEX:   1
IM_URL:          sw00672236000msuni0094.fits
SUN_POSTN:       313.34d {+20h 53m 22s}  -17.50d {-17d 29' 56"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.15d {+14h 04m 37s}   -9.08d {-09d 05' 03"}
MOON_DIST:       130.23 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.46,-29.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:26:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.207d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.056d {-07d 03' 22"} (J2000)
ROLL:            244.960d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30110.49 SOD {08:21:50.49} UT,   78.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     475921326
X_OFFSET:        1077 [pixels]
Y_OFFSET:        901 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1237
Y_GRB_POS:       1061
BINNING_INDEX:   1
IM_URL:          sw00672236000msuni0094.fits
SUN_POSTN:       313.34d {+20h 53m 22s}  -17.50d {-17d 29' 55"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.16d {+14h 04m 37s}   -9.09d {-09d 05' 06"}
MOON_DIST:       130.24 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.46,-29.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:28:42 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     672236,   Seg_Num: 0
GRB_RA:           78.1680d {+05h 12m 40.32s} (J2000),
                  78.3632d {+05h 13m 27.17s} (current),
                  77.5613d {+05h 10m 14.70s} (1950)
GRB_DEC:          -7.0497d {-07d 02' 58.9"} (J2000),
                  -7.0315d {-07d 01' 53.3"} (current),
                  -7.1082d {-07d 06' 29.6"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         13.88 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30108.00 SOD {08:21:48.00} UT,   76.0 [sec] since BAT Trigger Time
SUN_POSTN:       313.34d {+20h 53m 22s}  -17.50d {-17d 29' 54"}
SUN_DIST:        120.42 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.17d {+14h 04m 41s}   -9.09d {-09d 05' 20"}
MOON_DIST:       130.29 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.87,-25.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       76.42,-29.93 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 7.6 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:31:39 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.209d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.055d {-07d 03' 17"} (J2000)
POINT_ROLL:      244.959d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30322.47 SOD {08:25:22.47} UT,   290.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.773
N_STARS:         30
X_OFFSET:        757 [pixels]
Y_OFFSET:        581 [pixels]
X_MAX:           1716 [pixels]
Y_MAX:           1540 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00672236000msufc0290.fits
SUN_POSTN:       313.34d {+20h 53m 23s}  -17.50d {-17d 29' 52"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.19d {+14h 04m 46s}   -9.10d {-09d 05' 44"}
MOON_DIST:       130.27 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.47,-29.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:31:55 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.209d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.055d {-07d 03' 17"} (J2000)
POINT_ROLL:      244.959d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30322.47 SOD {08:25:22.47} UT,   290.5 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.773
N_STARS:         30
X_OFFSET:        757 [pixels]
Y_OFFSET:        581 [pixels]
X_MAX:           1716 [pixels]
Y_MAX:           1540 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00672236000msufc0290.fits
SUN_POSTN:       313.35d {+20h 53m 23s}  -17.50d {-17d 29' 52"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.20d {+14h 04m 47s}   -9.10d {-09d 05' 46"}
MOON_DIST:       130.27 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.47,-29.94 [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 31 Jan 16 08:33:02 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.209d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.055d {-07d 03' 17"} (J2000)
ROLL:            244.959d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30322.47 SOD {08:25:22.47} UT,   290.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     475921538
X_OFFSET:        1077 [pixels]
Y_OFFSET:        901 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1237
Y_GRB_POS:       1061
BINNING_INDEX:   1
IM_URL:          sw00672236000msuni0306.fits
SUN_POSTN:       313.35d {+20h 53m 23s}  -17.50d {-17d 29' 51"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.20d {+14h 04m 49s}   -9.10d {-09d 05' 55"}
MOON_DIST:       130.28 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.47,-29.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 31 Jan 16 08:33:15 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     672236,   Seg_Num: 0
POINT_RA:         78.209d {+05h 12m 50s} (J2000)
POINT_DEC:        -7.055d {-07d 03' 17"} (J2000)
ROLL:            244.959d
IMG_START_DATE:  17418 TJD;    31 DOY;   16/01/31
IMG_START_TIME:  30322.47 SOD {08:25:22.47} UT,   290.5 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     475921538
X_OFFSET:        1077 [pixels]
Y_OFFSET:        901 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1237
Y_GRB_POS:       1061
BINNING_INDEX:   1
IM_URL:          sw00672236000msuni0306.fits
SUN_POSTN:       313.35d {+20h 53m 23s}  -17.50d {-17d 29' 51"}
SUN_DIST:        120.46 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      211.21d {+14h 04m 50s}   -9.10d {-09d 05' 57"}
MOON_DIST:       130.28 [deg]
MOON_ILLUM:      58 [%]
GAL_COORDS:      207.90,-25.11 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.47,-29.94 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #18951
K. L. Page (U Leicester) and S. D. Barthelmy (GSFC) report on behalf of the Swift Team:
At 08:20:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160131A (trigger=672236). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 78.182, -7.067 which is
```
   RA(J2000)  =  05h 12m 44s
   Dec(J2000) = -07d 04' 02"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a large FRED-like peak structure with a duration of about 100 sec. The peak count rate was ~8100 counts/sec (15-350 keV), at ~16 sec after the trigger.
The XRT began observing the field at 08:21:41.6 UT, 69.7 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 78.1700, -7.0489 which is equivalent to:
```
   RA(J2000)  = +05h 12m 40.80s
   Dec(J2000) = -07d 02' 56.0"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 77 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
The initial flux in the 2.5 s image was 1.29e-08 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 78 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	05:12:40.34 =  78.16810
  DEC(J2000) = -07:02:59.1  =  -7.04975
```
with a 90%-confidence error radius of about 0.61 arc sec. This position is 7.5 arc sec. from the center of the XRT error circle. The estimated magnitude is 13.88 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.11.
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 Circular #18952
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik Kislovodsk Solar Station of the Pulkovo Observatory
D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the GRB160131.35 5180 sec after notice time and 5180 sec after trigger time at 2016-01-31 09:46:52 UT. On our 48-th (60s exposure) set we found 1 optical transient within Swift error-box (ra=05 12 40 dec=-07 02 57 r=0.050000) brighter then 16.7.
```
 T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|------
    5210   2016-01-31 09:46:52      60   (05h 12m 40.36s , -07d 02m 58.5s)  +15.55
```
The 5-sigma upper limit has been about 16.7mag The message may be cited.
GCN Circular #18953
C. Guidorzi, S. Dichiara (U. Ferrara), S. Kobayashi (LJMU), A. Gomboc (U. Nova Gorica), C.G. Mundell (U. Bath), on behalf of a larger collaboration report:
The 2-m LCOGT Faulkes Telescope North began observing Swift GRB160131A (Page et al. GCN 18951) on Jan 31 at 09:37 UT (~77 minutes after the burst trigger) with griZY filters. We clearly detect the optical afterglow (Page et al. GCN 18951; Yurkov et al. GCN 18952), with a magnitude of r=15.29 +- 0.01 at 81 minutes post GRB, as calibrated against nearby USNOB-1 star RA(J2000)=05:12:41.5 DEC(2000)=-07:03:09.81 with R2=14.28. Observations are going on.
GCN Circular #18954
L. P. Xin, X. F. Wang, J. Y. Wei, Y. L. Qiu, J. S. Deng, X. M. Meng D. Xu, J. Wang, X. H. Han and C. Wu on behalf of EAFON report:
We observed GRB 160131A (Page et al. GCN 18951) with Xinglong 0.8-m TNT telescope at 10:22:09UT, about 2 hours after the burst. The optical afterglow (Page et a.., GCN 18951, YurKov et al., GCN 18952) was detected in our white, B, and R, I-band images. The brightness of the optical afterglow is about 16.1 mag at the mid time of 118 min afer the burst, calibrated by the USNO B1.0 star (RA=05:12:39.8 DEC=-7:02:02 R2=15.51mag).
The message may be cited.
GCN Circular #18955
L. P. Xin, X. M. Meng, Y. J. Xiao, J. Y. Wei, E. W. Liang, X. G. Wang, Y. G. Yang, X. M. Lu, L. Huang, X. H. Han , H. B. Cai, Y. L. Qiu, J. Wang, C. Wu, J. S. Deng, H. L. Li and D. Xu report:
We observed GRB 160131A (Page et al. GCN 18951) with 60cm WFT telescope at 10:29:14UT, about 127 min after the burst. The optical afterglow (Page et a.., GCN 18951, YurKov et al., GCN 18952, Guidorzi et al., GCN 18953, Xin et al., 18954) was detected in our white and R-band images. The brightness of the optical afterglow is about 15.85 mag at the mid time of 127.5 min afer the burst, calibrated by the USNO B1.0 star (RA=05:12:39.8 DEC=-7:02:02 R2=15.51mag).
Observations are continuing
The message may be cited.
GCN Circular #18956
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 160131A (Page et al., GCN Circular 18951) 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 2016/01 31.35 to 2016/01 31.37 UTC (0.07 to 0.50 hours after the BAT trigger), obtaining a total of 0.18 hours exposure in the r, i, and z bands.
We detect a bright uncatalogued source at 05:12:40.33 -07:03:00 (J2000, =B10.5 arcsec). In comparison with the USNO-B1 catalog, we obtain the following mean magnitudes:
```
 r	=3D 13.35 =B1 0.04
 i	=3D 13.01 =B1 0.02
 z	=3D 12.67 =B1 0.04
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
The source fades roughly as t^-0.87 during our observations. This source is presumably the optical counterpart reported by Page et al. (GCN Circular 18951), Yurkov et al. (GCN Circular 18952), Guidorzi et al. (GCN Circular 18953), and Xin et al. (GCN Circular 18954).
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #18957
D. Xu (NAOC/CAS), Y.-H. Han (NAOC/CAS, HUST), Y.-D. Hu (IAA-CSIC), Y. Qing (Geneva Observatory), L.-P. Xin (NAOC/CAS) report on behalf of a larger collaboration:
We observed the field of GRB 160131A (Page & Barthelmy, GCN 18951) using the LCOGT-1m located at the Siding Spring Observatory. Observations started at 11:50:49 UT and ended at 12:15:46 UT on 2016-01-31 (i.e., 3.505 - 3.921 hr after the BAT trigger) and a series of 150s U-/B-/V-/R-/I-band frames were obtained.
The afterglow of the burst (e.g., Page & Barthelmy, GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 1894,18955; Watson et al., GCN 18956) is detected in our individual image in each band. Preliminary analysis gives rise to the following magnitudes:
```
m(I) = 16.05 +/- 0.02
m(R) = 16.56 +/- 0.02
m(V) = 17.07 +/- 0.02
m(B) = 17.59 +/- 0.02
```
calibrated with four SDSS stars in the field.
GCN Circular #18958
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 2574 s of XRT Photon Counting mode data and 2 UVOT images for GRB 160131A, 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 = 78.16795, -7.04988 which is equivalent to:
```
RA (J2000): 05h 12m 40.31s
Dec (J2000): -07d 02' 59.6"
```
with an uncertainty of 2.2 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 #18959
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), 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-240 to T+962 sec from the recent telemetry downlinks, we report further analysis of BAT GRB 160131A (trigger #672236) (Page, et al., GCN Circ. 18951). The BAT ground-calculated position is RA, Dec = 78.170, -7.037 deg, which is
```
   RA(J2000)  =  05h 12m 40.8s 
   Dec(J2000) = -07d 02' 13.0" 
```
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 64%.
The mask-weighted light curves shows a small precursor starting at ~T-2 sec and the main peak is a FRED starting at ~T+10 sec, peaking at ~T+18 sec, and returning to baseline at ~T+800 sec (although there is a possibility that it goes longer but the observing window ended at T+950 sec). T90 (15-350 keV) is 325 +- 72 sec (estimated error including systematics).
The time-averaged spectrum from T-1.49 to T+773.03 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.24 +- 0.05. The fluence in the 15-150 keV band is 2.04 +- 0.05 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+15.97 sec in the 15-150 keV band is 6.4 +- 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/672236/BA/

GCN Circular #18960
Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report:
We have detected GRB 160131A optical afterglow at iTelescope observatory (Siding Spring, Australia) using T9 0.32-m f/9 RCOS telescope and T17 and T32 0.43-m f/6.8 astrographs. The observations were started at 2016-01-31 10:01:17 (UT). Several images using photometric R and V filters with 300 sec and 120 sec exposure time were taken.
The afterglow was detected at the position RA 05:12:40.34 and DEC -07:02:58.3.
The following magnitudes were obtained from the observations using NOMAD1 0829-0078536 (R=15.390 and V=14.820) as a comparison star:
T32 observations

Tmid(s)+T0    Filter     Exp. time             Mag          Mag. Err.
6197              V          300s                   15.05          0.04
6796              V          300s                   15.17          0.04
7395              V          300s                   15.28          0.04

T17 observations

Tmid(s)+T0    Filter      Exp. time            Mag          Mag. Err.
6651              R           4x300s              15.71          0.02
7946              R           4x300s              15.96          0.02
11649            R           4x300s              16.56          0.03
12952            R           4x300s              16.68          0.03
14244            R           4x300s              16.86          0.04
15709            R           4x300s              16.99          0.04

T9 observations

Tmid(s)+T0    Filter      Exp. time             Mag          Mag. Err.
14761           V            5x120s              16.27          0.34
15454           V            5x120s              16.43          0.37
16190           V            5x120s              16.55          0.42
17083           V            5x120s              16.55          0.44
17767           V            5x120s              16.59          0.43
18452           V            5x120s              16.65          0.48
19179           V            5x120s              16.70          0.54
20295           V            5x120s              16.75          0.56

GCN Circular #18961
A. Melandri, P. D'Avanzo (INAF/OAB), V. D'Elia (INAF/OAR and ASI/ASDC), L. Di Fabrizio, G. Mainella (INAF/TNG) report on behalf of the CIBO collaboration:
We observed the field of GRB 160131A (Page et al., GCN 18951) with the 3.6m TNG telescope equipped with the DOLoRes camera in imaging mode. Observations started on 2016 Jan 31 at 19:52 UT and consisted of two images (120s each) obtained with the R filter.
The optical afterglow (Page et al., GCN 18951; Yurkov et al. GCN 18952; Guidorzi et al. GCN 18953; Xin et al., GCN 18954, GCN 18955; Watson et al. GCN 18956; Xu et al. GCN 18957) is clearly detected. From a preliminary analysis, we estimate a magnitude of R=18.1 +/- 0.1, calibrated against the USNO-B1 catalogue.

GCN Circular #18962
E. Mazaeva (IKI), S. Schmalz (AIP), N. Tungalag (Research Center of Astronomy and Geophysics MAS), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of Swift GRB 160131A (Page et al., GCN Page) with ORI-40 telescope of Khureltogot observatory on Jan., 31 from(UT) 11:14 up to (UT) 16:34. We obtained several unfilteed images. We clearly detect optical afterglow (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956). Preliminary photometry of the afterglow in the first images is following

Date        UT start t-T0 Filter Exp. OT Err 
                    (mid, days) (s)

2016-01-31  11:14:41 0.12106     20   16.43      0.10
2016-01-31  11:27:26 0.13015     60   16.49      0.04
2016-01-31  11:28:30 0.13089     60   16.51      0.04
2016-01-31  11:29:35 0.13164     60   16.50      0.04
2016-01-31  11:30:39 0.13238     60   16.52      0.05
2016-01-31  11:31:43 0.13388     60   16.61      0.05
2016-01-31  11:33:52 0.13462     60   16.46      0.04
2016-01-31  11:34:57 0.13537     60   16.53      0.05
2016-01-31  11:36:01 0.13611     60   16.58      0.05
2016-01-31  11:37:06 0.13686     60   16.62      0.05
2016-01-31  11:38:10 0.13760     60   16.56      0.04
2016-01-31  11:39:14 0.13834     60   16.58      0.04
2016-01-31  11:40:18 0.13909     60   16.57      0.04

Photometry is based on nearby USNO B1.0 stars, R2 magnitude.

GCN Circular #18963
S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M. McCauley (PSU) and K.L. Page report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 160131A (Page et al. GCN Circ. 18951), from 60 s to 23.6 ks after the BAT trigger. The data comprise 523 s in Windowed Timing (WT) mode (the first 8 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 Goad et al. (GCN Circ. 18958).
The late-time light curve (from T0+3.8 ks) can be modelled with a power-law decay with a decay index of alpha=1.09 (+/-0.05).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.44 (+/-0.03). The best-fitting absorption column is 1.76 (+/-0.15) x 10^21 cm^-2, in excess of the Galactic value of 1.1 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.10 (+/-0.08) and a best-fitting absorption column of 2.56 (+0.31, -0.29) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.56 (+0.31, -0.29) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^21 cm^-2
Excess significance: 7.9 sigma
Photon index:	     2.10 (+/-0.08)
```
If the light curve continues to decay with a power-law decay index of 1.09, the count rate at T+24 hours will be 0.053 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x 10^-12 (2.8 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00672236.
This circular is an official product of the Swift-XRT team.
GCN Circular #18964
U.Quadri, L.Strabla and R.Girelli report:
We imaged the field of GRB 160131A (Page et al., GCN Circular 18951) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy (member of ISSP:Italian Supernovae Search Project)
The observations started 9.18 hour after the GRB trigger, at the end of twilight, with our Newton telescope D=250 mm F/D=4.8
Initially weather conditions were good, but then the fog has forbidden the observations.
We co-added 2 series of 10 exposures of 60 sec each: Start T0 + 9.18 hour. End T0+ 9.87 hour
We clearly detect the optical counterpart (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953;Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956). at the following coordinates:
05h 12m 40.37s -07d 02m 58.9s +/-2 arcsec
Photometry was performed using comparison stars with UCAC4 catalog. in CV (clear + Jhonson V) and CR (Clear + Jhonson R) magnitudes, and are not corrected for galactic dust extinction:
```
------------------------------------
      JD         Mag    Filter   SNR
------------------------------------ 
2457419.24025   17.360   CR    14.34 
2457419.26062   17.241   CR     9.74 

2457419.24025   17.671   CV    14.40 
2457419.26062   17.498   CV     9.74 
-------------------------------------
```
The images are available at: http://www.osservatoriobassano.org/GRB.asp
The message may be cited.
GCN Circular #18965
D. Malesani (DARK/NBI), V. D'Elia (INAF/OAR and ASI/ASDC), P. D'Avanzo, A. Melandri (INAF-OAB), L. A. Antonelli (INAF/OAR and ASI/ASDC), L. Di Fabrizio, G. Mainella (INAF/TNG) report on behalf of the CIBO collaboration:
Following the observations reported in Melandri et al. (GCN 18961), we carried out further observations of the optical afterglow of GRB 160131A (Page et al., GCN 18951) with the 3.6m TNG telescope equipped with the DOLoRes camera in spectroscopic mode. A spectrum was acquired with the LR-B grism covering the range between 3500 and 8000 AA. The observation consisted of a single 1200 s exposure, starting on 2016 Jan 31 at 20:12 UT.
A preliminary analysis of the spectrum (based on archival calibration files) shows clearly the continuum with several absorption features due to Fe II, Mg II and Mg I at a common redshift of 0.97, which we propose as the redshift of the GRB.
We acknowledge support from the TNG visiting astronomer Ennio Poretti.
GCN Circular #18966
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), and R. Sanchez-Ramirez (IAA-CSIC) report on behalf of a larger collaboration:
We observed the afterglow of GRB 160131A (Page et al. GCN 18951) with the 10.4 m GTC equipped with OSIRIS. Observations consisted of 3x600s spectra with grism R1000B (covering from 3700 to 7800 AA) and 3x600s with grism R1000R (covering from 5100 to 10000 AA). The first spectrum started at 21:52 UT (13.53 hr after the GRB onset) under very bad seeing conditions (> 3").
In spite of the poor seeing we detect a strong continuum across the complete range with multiple absorption features of FeII, NiII, MnII, MgII, MgI, and CaII at a common redshift of 0.972, consistent with the value measured by Malesani et al. from TNG (GCN 18965).
GCN Circular #18967
F. Knust, J. Bolmer, J. Greiner (all MPE Garching), and D. A. Kann, (TLS Tautenburg) report on behalf of the GROND team:
We observed the field of GRB 160131A (Swift trigger 672236; Page et al., GCN #18951) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla Observatory (Chile).
Observations started at 0:44 UT on 2016-02-01, 16 hrs after the GRB trigger, and are continuing. They were performed at an average seeing of 1.3" and at an average airmass of 1.1.
We found a single point source within the 2.2" Swift-XRT error circle reported by Goad et al. (GCN #18958), in agreement with the UVOT afterglow (Page et al., GCN #18951) at
```
RA (J2000.0) = 05 h 12 m 40.32 s
Dec. (J2000.0) = -07d 02' 58.92
```
with an uncertainty of 0.5" in each coordinate.
Based on the first 4.40 min of total exposures in g'r'i'z' and 4.0 min in JHK, we estimate preliminary magnitudes (all in AB system) of
```
g' = 18.7 +/- 0.05 mag,
r' = 18.4 +/- 0.05 mag,
i' = 18.3 +/- 0.05 mag,
z' = 18.2 +/- 0.05 mag,
J  = 17.7 +/- 0.1 mag,
H  = 17.6 +/- 0.1 mag, and
K  = 17.1 +/- 0.1 mag.
```
Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.09 mag in the direction of the burst (Schlafly & Finkbeiner 2011).
GCN Circular #18968
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 160131A (Pagani and Barthelmy, GCNC 18951) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 2016-01-31 14:06:17 UT (~5.8 h afterthe burst). We detected the previously reported afterglow (Pagani and Barthelmy, GCNC 18951; Yurkov et al., GCNC 18952; Guidorzi et al., GCNC 18953) in all the three bands.
Photometric results of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'   g'_err  Rc   Rc_err  Ic   Ic_err
-----------------------------------------------------------------------
0.24373    14:11:29     540.0    17.92 0.09   17.19 0.05   16.88 0.06
-----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18969
D. Xu, L.-P. Xin, J. Wang (NAOC/CAS) report on behalf of a larger collaboration:
We observed the optical afterglow of GRB 160131A (e.g., Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954) using the 2.16m telescope located at Xinglong, Heibei, China, equipped with the BFOSC camera. A 2400s spectrum was acquired with the G4+385LP grism covering the range of 3500 - 8500 AA, starting at 13:49:08 UT on 2016-01-31.
The spectrum shows a continuum across the whole range, superimposed with absorption features of Mg II, Ca II H+K at a common redshift of 0.97, being consistent with measurements by Malesani et al. (GCN 18965) and de Ugarte Postigo et al. (GCN 18966).
We thank the excellent support of the Xinlong 2.16m staff, in particular Meng Zhai and Junjun Jia.

GCN Circular #18970
L. M. McCauley (PSU), K. L. Page (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160131A 78 s after the BAT trigger (Page et al., GCN Circ. 18951). A fading source consistent with the XRT position (Beardmore et al. GCN Circ. 18159) is detected in the initial UVOT exposures.
The preliminary UVOT position is:

    RA  (J2000) =  05:12:40.33 =  78.16804 (deg.)
    Dec (J2000) = -07:02:58.81  =  -7.04967 (deg.)

with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
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_fc              78         228         147          13.77+-1.10
white               5051       11361        1081          16.71+-0.02
v                   4026        5662         393          15.72+-0.03
b                   4846       10449        1138          16.81+-0.02
u                    290         540         245          13.08+-0.03
u                   4641        6277         393          15.64+-0.03
uvw1                4436        6072         393          16.18+-0.04
uvm2                4231        5867         393          16.64+-0.06
uvw2                3821       12083        1098          17.43+-0.05

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 #18971
E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the Swift GRB 160131A (Page et al., GCN 18951) with AZT-33IK telescope of Sayan observatory (Mondy) starting on Feb.01 (UT) 13:01:56. We clearly detect optical afterglow (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956). Preliminary photometry of the afterglow of the first image is following
```
Date        UT start   t-T0    Filter   Exp.   OT     Err.
                       (mid, days)       (s)

2016-02-01  13:01:56  1.19543  R        1*120  19.40  0.08
```
GCN Circular #18972
E. Mazaeva (IKI), R. Inasaridze (AbAO), V. Ayvazian (AbAO), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of Swift GRB 160131A (Page et al., GCN 18951) with AS-32 (0.7m) telescope of Abastumani Observatory starting on Jan. 31 (UT) 19:16:57. We obtained several unfiltered images of 120 s exposure. We detect optical afterglow (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956). Preliminary light curve can be found in http://grb.rssi.ru/GRB160131A/GRB160131A_20160131_AbAO_lc.png
The photometry is base on nearby USNO-B1.0 stars:
```
USNO-B.1_id  R2
0829-0078223 15.70
0829-0078147 14.56
0828-0074893 14.88
0828-0074768 14.81
```
GCN Circular #18973
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), V. Casanova (IAA-CSIC) and F. Aceituno (IAA-CSIC) report:
We observed the afterglow of GRB 160131A (Page et al. GCN 18951) from the 1.5m telescope (T150), at Sierra Nevada Observatory (Granada, Spain) in two epochs on the first and second night after the GRB.
In the first epoch we performed observations in the V, R and I filters and the object is well detected in all bands. During these observations on January 31.807 (10.8 hr after the burst), the object has a magnitude of R=17.90+/-0.02 (Vega), using as reference star the same USNO-B1.0 object mentioned in the circular by Xin et al. (GCN 18954).
On the second night we performed photometry in 5 bands, U, B, V, R and I, the object is again detected in all bands. In an image with mean epoch February 1.835 (35.5 hr after the burst) we detect the object at R=19.83+/-0.03.
GCN Circular #18974
A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline on behalf of the Konus-Wind team, report:
The long-duration, extremely hard-spectrum GRB 160131A (Swift-BAT trigger #672236: Page & Barthelmy, GCN 18951; Cummings et al., GCN 18959) triggered Konus-Wind at T0=30044.577 s UT (08:20:44.577).
The burst light curve shows a single, FRED-like pulse with a total duration (80-1400 keV) of ~200 s. In the softest KW energy band the emission can be traced up to ~300 s. The emission is seen up to ~15 MeV.
As observed by Konus-Wind, the burst had a fluence of 3.26(-0.32,+0.31)x10^-4 erg/cm2, and a 64-ms peak energy flux, measured from T0+2.704 s, of 2.23(-0.46,+0.46)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+162.048 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.97(-0.15,+0.24), the high energy photon index beta = -1.56(-0.10,+0.07), the peak energy Ep = 586(-259,+518) keV, chi2 = 98/97 dof.
The spectrum near the peak count rate (measured from T0+0.256 to T0+14.592 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.94(-0.18,+0.13), the high energy photon index beta = -1.56(-0.56,+0.06), the peak energy Ep = 1152(-438,+3060) keV, chi2 = 135/97 dof.
Assuming the redshift z=0.972 (Malesani et al., GCN 18965; de Ugarte Postigo, Thoene & Sanchez-Ramirez, GCN 18966; Xu, Xin & Wang, GCN 18969) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, and Omega_Lambda = 0.73, we estimate the following rest-frame parameters: the isotropic energy release E_iso is ~8.3x10^53 erg, the peak luminosity L_iso is ~1.1x10^53 erg/s, and the rest-frame peak energy of the time-integrated spectrum, Ep,i, is ~1150 keV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB160131_T30044/
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #18976
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), S. Schulze (PUC, MAS), M. Bremer (IRAM), S. Mart=EDn (JAO), J. M. Winters (IRAM) report on behalf a larger collaboration:
We conduced millimetre observations of GRB160131A (Page et al., GCN 18951) with the NOrthern Extended Millimeter Array (NOEMA; Plateau de Bure, France) at 93 and 150 GHz. Observations started at 17:05 UT on February 1 (i.e. 1.36 days after the burst).
We clearly detect the afterglow at both frequencies. A preliminary analysis of the 93 GHz data reveals a flux density of 1.94 +/- 0.07 mJy. Further observations are scheduled.
We encourage follow-up observations at all frequencies.
GCN Circular #18977
T. Laskar (NRAO / UC Berkeley), K. D. Alexander, and E. Berger (Harvard) report on behalf of a larger collaboration:
"We observed GRB 160131A (Page & Barthelmy; GCN 18951) at multiple frequencies with the Karl G. Jansky Very Large Array (VLA) beginning on 2016 February 01.11 UT (0.76 days after the burst). At a mean frequency of 21.8 GHz, we detect a radio source with a preliminary flux density of ~ 0.53 mJy at
```
RA = 15:12:40.351 +/- 0.001
Dec = -07:02:58.80 +/- 0.02
```
consistent with the enhanced Swift/XRT position (Goad et al.; GCN 18958) and the optical position (Page & Barthelmy.; GCN 18951, Yurkov et al.; GCN 18952). Follow-up observations are planned. We thank the VLA staff for rapidly scheduling these observations."
GCN Circular #18978
T. Laskar (NRAO / UC Berkeley) reports:
"Our original circular (Laskar et al.; GCN 18977) contained a typo in the right ascension of the radio source. The correct position is
```
RA = 05:12:40.351 +/- 0.001
Dec = -07:02:58.80 +/- 0.02
```
Thanks to Frank Marshall for pointing out the error."
GCN Circular #18988
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 160131A (Page, et al., GCN 18951) 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 2016/02 4.10 to 2016/02 4.36 UTC (89.96 to 96.25 hours after the BAT trigger), obtaining a total of 4.60 hours exposure in the r, i, and z bands.
For a source within the Swift-XRT error circle (Osborne, et al., GCN 18958), in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following detections and upper limit (3-sigma):
```
  r =3D 21.64 +/- 0.05
  i =3D 21.41 +/- 0.03
  z > 20.48
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We note that there is a faint, possible source present in the DSS near this source which could be the GRB host galaxy.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #18991
A. Volnova (IKI), E. Mazaeva (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the Swift GRB 160131A (Page et al., GCN 18951) with AZT-33IK telescope of Sayan observatory (Mondy) starting on Feb.04 (UT) 11:42:43. We detect optical afterglow (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956) in a combined image. Preliminary photometry is following
```
Date        UT start   t-T0    Filter   Exp.   OT     Err.
                       (mid, days)       (s)

2016-02-04  11:42:43  4.16058  R       29*120  21.70  0.23

USNO-B.1_id     R2

0829-0078147    14.56
0829-0078222    18.96
0829-0078226    18.69
0829-0078129    17.62
```
GCN Circular #18992
E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Kusakin (Fesenkov Astrophysical Institute), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the Swift GRB 160131A (Page et al., GCN 18951) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory starting on Feb. 05 (UT) 14:22:45. We obtained several images in R filter. We clearly detect optical afterglow (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956) in a combined image. Preliminary photometry is following
```
Date        UT start   t-T0    Filter   Exp.   OT     Err.
                       (mid, days)       (s)

2016-02-05  14:22:45   5.28802 R       21*300  22.40  0.20
```
Photometry is based on nearby USNO-B1.0 stars
```
USNO-B.1_id  R2

0829-0078223 15.70
0829-0078147 14.56
0829-0078167 17.71
0829-0078222 18.96
0829-0078226 18.69
0829-0078129 17.62
```
GCN Circular #19004
E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Kusakin (Fesenkov Astrophysical Institute), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the Swift GRB 160131A (Page et al., GCN 18951) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We obtained several images in R filter on Feb. 06 and Feb. 07.The optical afterglow (Page et al., GCN 18951; Yurkov et al., GCN 18952; Guidorzi et al., GCN 18953; Xin et al., GCN 18954; Xin et al., GCN 18955; Watson et al., GCN 18956) is detected on Feb. 06 and not detected on Feb. 07. Preliminary photometry is following
```
Date        UT start   t-T0    Filter  Exp.   OT     Err.
                       (mid, days)     (s)

2016-02-06 13:45:54   6.26762 R       21*300 22.40   0.3
2016-02-07 13:30:04   7.25330 R       21*300 >22.40 (3sigma)
```
Photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id R2
```
0829-0078223 15.70
0829-0078147 14.56
0829-0078167 17.71
0829-0078222 18.96
0829-0078226 18.69
0829-0078129 17.62
```
GCN Circular #19009
Poonam Chandra (NCRA-TIFR) and A. J. Nayana (NCRA-TIFR) report on behalf of a larger collaboration:
We carried out the Giant Metrewave Radio Telescope (GMRT) observations of GRB 160131A (GCN Circ. 18951) at 1280 and 610 MHz band on 2016 Feb 09.61 UT. The data is badly affected by RFI and hence we could not obtain the expected rms. The 3-sigma upper limit on the GRB flux in the Swift error cicle (GCN Circ. 18970) are 570 and 382 uJy in 1280 and 610 MHz bands, respectively.
The GMRT data for GRB 160131A is public for anyone to use.
Further observations are planned. We thank GMRT staff for making these observations possible.
GCN Circular #19010
Poonam Chandra (NCRA-TIFR) and A. J. Nayana (NCRA-TIFR) report on behalf of a larger collaboration:
We reobserved GRB 160131A (GCN Circ. 18951) with the Giant Metrewave Radio Telescope (GMRT) at 1420 MHz band on 2016 Feb 10.78 UT. While we do not detect the GRB radio afterglow, we place very constraining 3-sigma upper limit on the GRB flux in the Swift error cicle (GCN Circ. 18970) to be 105 uJy.
The GMRT data for GRB 160131A is public for anyone to use.
Further observations are planned. We thank GMRT staff for making these observations possible.
GCN Circular #19011
S. V. Vadawale (PRL), T. Chattopadhyay (PRL), N. P. S. Mithun (PRL), A. R. Rao (TIFR), D. Bhattacharya (IUCAA), Varun Bhalerao (IUCAA) report on behalf of the Astrosat CZTI collaboration:
Astrosat CZT Imager detected GRB 160131A (Page and Barthelmy, GCN 18951) at an incident angle of 63 degrees from the telescope pointing axis. The T90 was measured to be 106 s and 97 s in 30 - 100 keV and 100 - 300 keV respectively. CZTI being sensitive to polarimetry [Chattopadhyay et al, 2014, EXPA, Vadawale et al 2015, A&A], we have analysed the double events due to Compton scattering and detect a clear azimuthal modulation of 0.30 +/- 0.12 %, with a detection significance of 2.5 sigma. Based on a preliminary mass modelling, we estimate that the source polarisation fraction lies between ~ 50 - 60 % in 100-300 keV band. A detailed mass modeling to refine this measurement and its estimated uncertainty is in progress. In an earlier event, GRB 151006A (Bhalerao et al. GCN 18422) CZT Imager data showed a marginal evidence for polarisation signal. From the higher detection confidence for this brighter GRB160131A, we estimate that CZT Imager can provide time resolved spectro-polarimetry for GRBs with fluence larger than 10^-4 erg per cm^2.
This message may be cited.
GCN Circular #19206
K. P. Mooley, R. P. Fender, T. D. Staley (Oxford), G. Ghirlanda, F. Nappo (INAF, Merate), C. Rumsey, D. Titterington, S. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)
We observed the XRT position of GRB 160131A discovered by Swift (Page et al., GCN 18951; Goad et al., GCN 18958) at 15 GHz with the Arcminute Microkelvin Imager (AMI-LA) on 2016 Feb 24.79 UT and Mar 06.79 UT, corresponding to 24.5 days and 34.5 days post-burst respectively. We do not detect any radio source at the XRT location, with 3sigma upper limits of 150 uJy and 210 uJy respectively.
We thank the AMI scheduling team for carrying out these observations.

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Jochen Greiner, last update: 17-Mar-2016 [Disclaimer]