Gamma-ray Burst 160104A

(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:     Mon 04 Jan 16 11:24:37 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     669319,   Seg_Num: 0
GRB_RA:           76.804d {+05h 07m 13s} (J2000),
                  77.026d {+05h 08m 06s} (current),
                  76.109d {+05h 04m 26s} (1950)
GRB_DEC:         +11.354d {+11d 21' 14"} (J2000),
                 +11.374d {+11d 22' 27"} (current),
                 +11.289d {+11d 17' 20"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3368 [cnts]    Image_Peak=189 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       19725 [cnts]
BKG_TIME:        41032.35 SOD {11:23:52.35} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17391 TJD;     4 DOY;   16/01/04
GRB_TIME:        41050.84 SOD {11:24:10.84} UT
GRB_PHI:         -63.58 [deg]
GRB_THETA:         6.14 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     15.71 [sigma]
IMAGE_SIGNIF:    8.69 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -1  +0  +0 +87  +0 
SUN_POSTN:       284.69d {+18h 58m 46s}  -22.75d {-22d 44' 57"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.56d {+14h 26m 14s}  -10.86d {-10d 51' 41"}
MOON_DIST:       140.32 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.06,-17.07 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       76.80,-11.48 [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 = 124.05,6.05 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(3.0<100sec) coincident with the FERMI_GBM event (trignum=473599457).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:24:50 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     473599457
GRB_RA:          339.600d {+22h 38m 24s} (J2000),
                 339.757d {+22h 39m 02s} (current),
                 339.110d {+22h 36m 26s} (1950)
GRB_DEC:         +57.060d {+57d 03' 36"} (J2000),
                 +57.144d {+57d 08' 37"} (current),
                 +56.799d {+56d 47' 58"} (1950)
GRB_ERROR:       51.55 [deg radius, statistical only]
DATA_SIGNIF:     5.40 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        17391 TJD;     4 DOY;   16/01/04
GRB_TIME:        41053.22 SOD {11:24:13.22} UT
GRB_PHI:         183.00 [deg]
GRB_THETA:       145.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:       284.69d {+18h 58m 46s}  -22.75d {-22d 44' 57"}
SUN_DIST:         92.20 [deg]   Sun_angle= -3.7 [hr] (East of Sun)
MOON_POSTN:      216.56d {+14h 26m 15s}  -10.86d {-10d 51' 43"}
MOON_DIST:       116.74 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      105.58, -1.26 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       17.42, 57.71 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn160104475/quicklook/glg_lc_medres34_bn160104475.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_473599457.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
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 ~4 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(3.0<100sec) coincident with the SWIFT_BAT event (trignum=669319).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:24:42 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     473599457
GRB_RA:           62.733d {+04h 10m 56s} (J2000),
                  62.980d {+04h 11m 55s} (current),
                  61.964d {+04h 07m 51s} (1950)
GRB_DEC:         +27.600d {+27d 36' 00"} (J2000),
                 +27.641d {+27d 38' 26"} (current),
                 +27.471d {+27d 28' 15"} (1950)
GRB_ERROR:       33.80 [deg radius, statistical plus systematic]
GRB_INTEN:       51 [cnts/sec]
DATA_SIGNIF:     4.70 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        17391 TJD;     4 DOY;   16/01/04
GRB_TIME:        41053.22 SOD {11:24:13.22} UT
GRB_PHI:         208.00 [deg]
GRB_THETA:        85.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.14
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,1, 0,0,1, 0,0,
SUN_POSTN:       284.69d {+18h 58m 46s}  -22.75d {-22d 44' 57"}
SUN_DIST:        142.12 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      216.56d {+14h 26m 15s}  -10.86d {-10d 51' 42"}
MOON_DIST:       150.06 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      168.14,-17.28 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       65.89,  6.41 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn160104475/quicklook/glg_lc_medres34_bn160104475.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 229.90,18.05 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(3.0<100sec) coincident with the SWIFT_BAT event (trignum=669319).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:25:41 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.811d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 21' 01"} (J2000)
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41130.07 SOD {11:25:30.07} UT,   79.2 [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:     Mon 04 Jan 16 11:27:42 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     669319,   Seg_Num: 0
GRB_RA:           76.804d {+05h 07m 13s} (J2000),
                  77.026d {+05h 08m 06s} (current),
                  76.109d {+05h 04m 26s} (1950)
GRB_DEC:         +11.354d {+11d 21' 14"} (J2000),
                 +11.374d {+11d 22' 27"} (current),
                 +11.289d {+11d 17' 20"} (1950)
GRB_DATE:        17391 TJD;     4 DOY;   16/01/04
GRB_TIME:        41050.84 SOD {11:24:10.84} UT
TRIGGER_INDEX:   146
GRB_PHI:         -63.58 [deg]
GRB_THETA:         6.14 [deg]
DELTA_TIME:      71.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     15.71 [sigma]
IMAGE_SIGNIF:    8.69 [sigma]
LC_URL:          sw00669319000msb.lc
SUN_POSTN:       284.69d {+18h 58m 46s}  -22.75d {-22d 44' 56"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.59d {+14h 26m 20s}  -10.87d {-10d 52' 05"}
MOON_DIST:       140.35 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.06,-17.07 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       76.80,-11.48 [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 = 124.05,6.05 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:28:30 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.811d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 20' 60"} (J2000)
POINT_ROLL:      243.117d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41135.92 SOD {11:25:35.92} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.809
N_STARS:         86
X_OFFSET:        534 [pixels]
Y_OFFSET:        579 [pixels]
X_MAX:           1493 [pixels]
Y_MAX:           1538 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00669319000msufc0085.fits
SUN_POSTN:       284.69d {+18h 58m 47s}  -22.75d {-22d 44' 56"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.59d {+14h 26m 22s}  -10.87d {-10d 52' 11"}
MOON_DIST:       140.35 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.80,-11.49 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:29:00 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.811d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 20' 60"} (J2000)
POINT_ROLL:      243.117d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41135.92 SOD {11:25:35.92} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.809
N_STARS:         86
X_OFFSET:        534 [pixels]
Y_OFFSET:        579 [pixels]
X_MAX:           1493 [pixels]
Y_MAX:           1538 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00669319000msufc0085.fits
SUN_POSTN:       284.69d {+18h 58m 47s}  -22.75d {-22d 44' 56"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.60d {+14h 26m 23s}  -10.87d {-10d 52' 15"}
MOON_DIST:       140.35 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.80,-11.49 [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:     Mon 04 Jan 16 11:29:51 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     669319,   Seg_Num: 0
GRB_RA:           76.7972d {+05h 07m 11.32s} (J2000),
                  77.0197d {+05h 08m 04.73s} (current),
                  76.1026d {+05h 04m 24.63s} (1950)
GRB_DEC:         +11.3238d {+11d 19' 25.6"} (J2000),
                 +11.3440d {+11d 20' 38.3"} (current),
                 +11.2586d {+11d 15' 30.8"} (1950)
GRB_ERROR:       3.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41166.00 SOD {11:26:06.00} UT,   115.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       284.70d {+18h 58m 47s}  -22.75d {-22d 44' 56"}
SUN_DIST:        151.26 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.60d {+14h 26m 25s}  -10.87d {-10d 52' 22"}
MOON_DIST:       140.37 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.08,-17.09 [deg] galactic lon,lat of the burst
ECL_COORDS:       76.79,-11.51 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:29:57 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.811d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 20' 60"} (J2000)
ROLL:            243.117d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41135.92 SOD {11:25:35.92} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     473599551
X_OFFSET:        853 [pixels]
Y_OFFSET:        898 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1058
BINNING_INDEX:   1
IM_URL:          sw00669319000msuni0101.fits
SUN_POSTN:       284.70d {+18h 58m 47s}  -22.75d {-22d 44' 56"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.60d {+14h 26m 25s}  -10.87d {-10d 52' 22"}
MOON_DIST:       140.36 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.80,-11.49 [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:     Mon 04 Jan 16 11:30:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.811d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 20' 60"} (J2000)
ROLL:            243.117d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41135.92 SOD {11:25:35.92} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     473599551
X_OFFSET:        853 [pixels]
Y_OFFSET:        898 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1058
BINNING_INDEX:   1
IM_URL:          sw00669319000msuni0101.fits
SUN_POSTN:       284.70d {+18h 58m 47s}  -22.75d {-22d 44' 55"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.61d {+14h 26m 26s}  -10.87d {-10d 52' 25"}
MOON_DIST:       140.36 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.80,-11.49 [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:     Mon 04 Jan 16 11:36:21 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 21' 01"} (J2000)
POINT_ROLL:      243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41348.22 SOD {11:29:08.22} UT,   297.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.807
N_STARS:         132
X_OFFSET:        294 [pixels]
Y_OFFSET:        339 [pixels]
X_MAX:           1733 [pixels]
Y_MAX:           1778 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00669319000msufc0297.fits
SUN_POSTN:       284.70d {+18h 58m 48s}  -22.75d {-22d 44' 54"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.66d {+14h 26m 37s}  -10.89d {-10d 53' 12"}
MOON_DIST:       140.41 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:36:44 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 21' 01"} (J2000)
POINT_ROLL:      243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41348.22 SOD {11:29:08.22} UT,   297.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.807
N_STARS:         132
X_OFFSET:        294 [pixels]
Y_OFFSET:        339 [pixels]
X_MAX:           1733 [pixels]
Y_MAX:           1778 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw00669319000msufc0297.fits
SUN_POSTN:       284.70d {+18h 58m 48s}  -22.75d {-22d 44' 54"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.66d {+14h 26m 38s}  -10.89d {-10d 53' 15"}
MOON_DIST:       140.41 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [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:     Mon 04 Jan 16 11:36:53 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     669319,   Seg_Num: 0
GRB_RA:           76.7964d {+05h 07m 11.13s} (J2000),
                  77.0189d {+05h 08m 04.53s} (current),
                  76.1018d {+05h 04m 24.44s} (1950)
GRB_DEC:         +11.3239d {+11d 19' 26.0"} (J2000),
                 +11.3441d {+11d 20' 38.7"} (current),
                 +11.2587d {+11d 15' 31.2"} (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:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41166.00 SOD {11:26:06.00} UT,   115.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       284.70d {+18h 58m 48s}  -22.75d {-22d 44' 54"}
SUN_DIST:        151.25 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.66d {+14h 26m 39s}  -10.89d {-10d 53' 16"}
MOON_DIST:       140.43 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.08,-17.09 [deg] galactic lon,lat of the burst
ECL_COORDS:       76.79,-11.51 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:37:44 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 21' 01"} (J2000)
ROLL:            243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41348.22 SOD {11:29:08.22} UT,   297.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     473599763
X_OFFSET:        853 [pixels]
Y_OFFSET:        898 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1058
BINNING_INDEX:   1
IM_URL:          sw00669319000msuni0313.fits
SUN_POSTN:       284.70d {+18h 58m 48s}  -22.75d {-22d 44' 54"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.67d {+14h 26m 40s}  -10.89d {-10d 53' 23"}
MOON_DIST:       140.42 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [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:     Mon 04 Jan 16 11:38:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.350d {+11d 21' 01"} (J2000)
ROLL:            243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41348.22 SOD {11:29:08.22} UT,   297.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     473599763
X_OFFSET:        853 [pixels]
Y_OFFSET:        898 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1058
BINNING_INDEX:   1
IM_URL:          sw00669319000msuni0313.fits
SUN_POSTN:       284.70d {+18h 58m 48s}  -22.75d {-22d 44' 53"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.67d {+14h 26m 41s}  -10.89d {-10d 53' 26"}
MOON_DIST:       140.42 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [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 #18815
A. Melandri (INAF-OAB), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), P. D'Avanzo (INAF-OAB), P.A. Evans (U Leicester), C. Gronwall (PSU) and K. L. Page (U Leicester) report on behalf of the Swift Team:
At 11:24:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160104A (trigger=669319). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 76.804, +11.354 which is
```
   RA(J2000) = 05h 07m 13s
   Dec(J2000) = +11d 21' 14"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed multiple weak peaks with a duration of about 20 sec. The peak count rate was ~1929 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 11:25:30.0 UT, 79.3 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 76.7965, 11.3239 which is equivalent to:
```
   RA(J2000)  = 05h 07m 11.17s
   Dec(J2000) = +11d 19' 25.9"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 111 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.71 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 85 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 none of the XRT error circle. 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 0.26.
Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:42:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.351d {+11d 21' 03"} (J2000)
POINT_ROLL:      243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41927.36 SOD {11:38:47.36} UT,   876.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.769
N_STARS:         190
X_OFFSET:        294 [pixels]
Y_OFFSET:        339 [pixels]
X_MAX:           1733 [pixels]
Y_MAX:           1778 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00669319000msufc0876.fits
SUN_POSTN:       284.71d {+18h 58m 49s}  -22.75d {-22d 44' 52"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.71d {+14h 26m 50s}  -10.90d {-10d 54' 02"}
MOON_DIST:       140.46 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 04 Jan 16 11:43:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.351d {+11d 21' 03"} (J2000)
POINT_ROLL:      243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41927.36 SOD {11:38:47.36} UT,   876.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.769
N_STARS:         190
X_OFFSET:        294 [pixels]
Y_OFFSET:        339 [pixels]
X_MAX:           1733 [pixels]
Y_MAX:           1778 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00669319000msufc0876.fits
SUN_POSTN:       284.71d {+18h 58m 49s}  -22.75d {-22d 44' 52"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.71d {+14h 26m 51s}  -10.90d {-10d 54' 06"}
MOON_DIST:       140.47 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [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:     Mon 04 Jan 16 11:44:23 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.351d {+11d 21' 03"} (J2000)
ROLL:            243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41927.36 SOD {11:38:47.36} UT,   876.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     473600343
X_OFFSET:        853 [pixels]
Y_OFFSET:        898 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1058
BINNING_INDEX:   1
IM_URL:          sw00669319000msuni0892.fits
SUN_POSTN:       284.71d {+18h 58m 50s}  -22.75d {-22d 44' 52"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.72d {+14h 26m 53s}  -10.90d {-10d 54' 14"}
MOON_DIST:       140.48 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [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:     Mon 04 Jan 16 11:44:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     669319,   Seg_Num: 0
POINT_RA:         76.812d {+05h 07m 15s} (J2000)
POINT_DEC:       +11.351d {+11d 21' 03"} (J2000)
ROLL:            243.115d
IMG_START_DATE:  17391 TJD;     4 DOY;   16/01/04
IMG_START_TIME:  41927.36 SOD {11:38:47.36} UT,   876.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     473600343
X_OFFSET:        853 [pixels]
Y_OFFSET:        898 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1013
Y_GRB_POS:       1058
BINNING_INDEX:   1
IM_URL:          sw00669319000msuni0892.fits
SUN_POSTN:       284.71d {+18h 58m 50s}  -22.75d {-22d 44' 52"}
SUN_DIST:        151.28 [deg]   Sun_angle= -10.2 [hr] (East of Sun)
MOON_POSTN:      216.72d {+14h 26m 54s}  -10.90d {-10d 54' 17"}
MOON_DIST:       140.48 [deg]
MOON_ILLUM:      29 [%]
GAL_COORDS:      190.07,-17.06 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.81,-11.49 [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 #18816
C. Guidorzi (U. Ferrara), S. Dichiara (U. Ferrara, ICRANet), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report:
The 2-m LCOGT Faulkes Telescope North began observing Swift GRB 160104A (Melandri et al. GCN 18815) on January 04, 11:50:08 UT (26 minutes after the burst trigger) with SDSS R and I filters. Within the XRT error circle we detect an uncatalogued source at the following position:
```
RA(J2000)=   05:07:11.058
DEC(J2000)= +11:19:25.4
```
with R~19 mag as calibrated against nearby USNOB-1 stars.
GCN Circular #18817
Y.Saito, T.Fujiwara, T. Yoshii, Y. Tano, Y. Tachibana, Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 160104A (A. Melandri et al., GCN Circular #18815) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2016-01-04 11:24:56 UT (46 sec after the burst) and we detected the optical counterpart in Rc and Ic band. The measured magnitudes were listed as follows.
We obtained following limits for the magnitudes.
```
T0+[sec]    MID-UT      T-EXP[sec]         g'              Rc                      Ic
-------------------------------------------------------------------------------------------------------
61            11:25:11             30            > 18.5        17.9 +/- 0.3        16.5 +/- 0.2 
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used GSC2.3 catalog for flux calibration.
GCN Circular #18819
K. Yanagisawa, D. Kuroda, Y. Shimizu, H. Izumiura(OAO/NAOJ), M. Yoshida (Hiroshima), K. Ohta(Kyoto) and N. Kawai(Tokyo Tech.) report on behalf of the MITSuME collaboration:
We observed the field of GRB 160104A (Melandri et al., GCN 18815) in Ks-band with a wide-field near infrared imager at Okayama Astrophysical Observatory (Japan). The imager has effective aperture of 0.91 m.
Observations started from 11:46 UT on 4th January, 0.38h after the BAT trigger, to 12:49 UT. The total exposure of 24.0 min was successfully obtained.
In our co-add image, we did not find any new point source within the XRT error circle down to the limiting magnitude of Ks=16.8 (Vega, S/N=3). The photometric calibration was made against 2MASS field stars.
```
T0+[sec]    MID-UT     T-EXP[sec]      Ks
---------------------------------------------------
  +3,235    12:18      1440.0          >16.8
---------------------------------------------------
T0+ : Elapsed time after the burt [sec]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18820
V.Yurkov, Yu.Sergienko, A.Gabovich, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
O. Gress, K. Ivanov, N.M. Budnev, V.A. Poleshchuk, S.A. Yazev Irkutsk State University
V. Lipunov, E. Gorbovskoy, N.Tyurina, D. Vlasenko, V.Kornilov, P.Balanutsa, A.Kuznetsov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute
R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
report on behalf of the MASTER Team:
MASTER-Amur robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the GRB160104A (Melandri et al., GCN 18815) 10 sec after notice time and 32 sec after trigger time at 2016-01-04 11:24:46 UT. On our first (10s exposure) set we have found optical transient with 17.0+/-0.3 unfiltered magnitude at LCOGT-FTN and MITSuME Akeno position (Guidorzi et al., GCN 18816; Saito et al., GCN 18817) The 5-sigma upper limit has been about 17.3 mag
MASTER-Tunka robotic telescope (MASTER-Net: http://observ.pereplet.ru) located near Bykal lake was pointed to the GRB160104A 66 sec after trigger time at 2016-01-04 11:25:20 UT. On our first (10s exposure) set we have found marginally optical transient ~17 unfiltered magnitude. The 5-sigma upper limit has been about 17.2mag
The reduction is continuated. The message may be cited.
GCN Circular #18821
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1777 s of XRT Photon Counting mode data and 2 UVOT images for GRB 160104A, 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 = 76.79604, +11.32393 which is equivalent to:
```
RA (J2000): 05h 07m 11.05s
Dec (J2000): +11d 19' 26.2"
```
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 #18823
L. P. Xin, X. F. Wang, J. Y. Wei, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han, C. Wu, D. Xu on behalf of EAFON report:
We observed GRB 160104A (Melandri et al. GCN 18815) with Xinglong 0.8-m TNT telescope at 11: 26:01UT, 111 sec after the burst.
The optical afterglow (Guidorzi et al., GCN 18816; Saito GCN 18817; Yurkov et al., GCN 18820 ) was detected in our white images. The brightness of the optical afterglow is about 18.45 mag at the mid time of 121 sec afer the burst, calibrated by the USNO B1.0 star (RA=05:07:08 DEC=11:02:02 R2=16.25mag).
The message may be cited.
GCN Circular #18825
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration:
We observed the field of GRB 160104A (Melandri et al., GCNC 18815) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2016-01-04 12:42:48 UT (~1.3 h after the burst). We could not detect the previously reported afterglow (Guidorzi et al., GCNC 18816; Saito et al., GCNC 18817) in all the three bands.
Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'    Rc     Ic
-----------------------------------------------------
0.08648    13:28:43    4620.0   >20.4  >20.0  >19.4
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18826
L. P. Xin, J. Y. Wei=EF=BC=8C Y. L. Qiu, E. W. Liang, X. H. Han, =20 Y. Xu, L. Huang, Y. G. Yang, X. M. Meng, H. B. Cai, =20 J. Wang, C. Wu, J. S. Deng and H. L. Li report:
The field of SWIFT GRB 160104A (Melandri et al. GCN 18815) was monitored by Mini-GWAC system continuously=20 during about 1.5 hrs before and 1 hrs after the burst trigger time. The exposure time for each frame is 10 sec.
No any new optical counterpart (Guidorzi et al., GCN 18816;=20 Saito GCN 18817; Xin et al., GCN 18823) in single frame=20 was detected down to the 5 sigma upper limit of 12.3 mag=20 during our observations, calibrated by nearby USNO B1.0 R2 mag,=20 at the epoch of prompt emission phase.
Combining 5 frames during and after the burst trigger initially with a to= tal=20 exposure time of 50 sec gives a 5 sigma upper limit of 12.8 mag.
Mini-GWAC system is located at Xinglong observatory, National Astronomical Observatories, China, including 6 mounts and 12 Canon 85/f1.2 cameras. Each mount is equipped with 2 cameras. For each camera, the Apogee U9000X CCD was used, which gives about 400 square degree of FOV. The total field of view of this system is about 5000 sq.deg.
This message may be cited.
GCN Circular #18827
L. P. Xin, J. Y. Wei, Y. L. Qiu, E. W. Liang, X. H. Han, Y. Xu, L. Huang, Y. G. Yang, X. M. Meng, H. B. Cai, J. Wang, C. Wu, J. S. Deng and H. L. Li report:
The field of SWIFT GRB 160104A (Melandri et al. GCN 18815) was monitored by Mini-GWAC system continuously during about 1.5 hrs before and 1 hrs after the burst trigger time. The exposure time for each frame is 10 sec.
No any new optical counterpart (Guidorzi et al., GCN 18816; Saito GCN 18817; Xin et al., GCN 18823) in single frame was detected down to the 5 sigma upper limit of 12.3 mag during our observations, calibrated by nearby USNO B1.0 R2 mag, at the epoch of prompt emission phase.
Combining 5 frames during and after the burst trigger initially with a total exposure time of 50 sec gives a 5 sigma upper limit of 12.8 mag.
Mini-GWAC system is located at Xinglong observatory, National Astronomical Observatories, China, including 6 mounts and 12 Canon 85/f1.2 cameras. Each mount is equipped with 2 cameras. For each camera, the Apogee U9000X CCD was used, which gives about 400 square degree of FOV. The total field of view of this system is about 5000 sq.deg.
This message may be cited.
GCN Circular #18828
R. Hamburg (UAH) and Hoi-Fung Yu (MPE) report on behalf of the Fermi GBM Team:
"At 11:24:13.22 UT on 04 January 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160104A (trigger 473599457 / 160104475), which was also detected by the Swift/BAT (A. Melandri et al. 2016, GCN 18815). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 104 degrees.
The GBM light curve consists of one main peak with a duration (T90) of about 10 s (50-300 keV). The time-averaged spectrum from T0-3.200 s to T0+0.128 s is adequately fit by a simple power law function with index -1.7 +/- 0.1.
The event fluence (10-1000 keV) in this time interval is (6.1 +/- 0.7)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-1.92 s in the 10-1000 keV band is 1.7 +/- 0.2 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #18829
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160104A (trigger #669319) (Melandri , et al., GCN Circ. 18815). The BAT ground-calculated position is RA, Dec = 76.808, 11.334 deg which is
```
   RA(J2000)  =  05h 07m 13.9s
   Dec(J2000) = +11d 20' 01.2"
```
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shows a two-peak episode with main peak starting ~T-3 sec, peaking at ~T+1 sec, and ending around T+10 sec, where second weak peak starts. The second pulse ends around ~T+20 sec. T90 (15-350 keV) is 16.2 +- 2.5 sec (estimated error including systematics).
The time-averaged spectrum from T-1.31 to T+17.65 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.76 +- 0.19. The fluence in the 15-150 keV band is 4.0 +- 0.5 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T-0.16 sec in the 15-150 keV band is 1.0 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/669319/BA/
GCN Circular #18830
A. Melandri, P. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
We have analysed 7.5 ks of XRT data for GRB 160104A (Melandri et al. GCN Circ. 18815), from 63 s to 36.3 ks after the BAT trigger. The data comprise 914 s in Windowed Timing (WT) mode (the first 9 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 Beardmore et al. (GCN Circ. 18821).
The light curve can be modelled with an initial power-law decay with an index of alpha=3.1 +/- 0.4, followed by a break at T+269 s to an alpha of 0.53 (+0.14, -0.17). Flaring activity is observed between T0+200 s and T0+2.0 ks.
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.95 (+0.18, -0.08). The best-fitting absorption column is consistent with the Galactic value of 2.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.7 (+/-0.6) x 10^21 cm^-2
Galactic foreground: 2.7 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.95 (+0.18, -0.08)
```
If the light curve continues to decay with a power-law decay index of 0.53, the count rate at T+24 hours will be 0.01 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.7 x 10^-13 (5.2 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/00669319.
This circular is an official product of the Swift-XRT team.
GCN Circular #18831
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), J.P.U. Fynbo (DARK/NBI), N.R. Tanvir (U. Leicester), R. Sanchez-Ramirez (IAA-CSIC) and S. Geier (GRANTECAN), report on behalf of a larger collaboration:
We observed the afterglow of GRB 160104A (Melandri et al. GCN18815, Guidorzi et al. GCN18816) with OSIRIS on the 10.4 m GTC telescope, located at the Roque de los Muchachos Observatory (La Palma, Spain). Observations started at 20:25 UT (9.0 hr after the GRB onset) and consisted of a 40 s acquisition image in i-band as well as 3x900s spectra using the R1000R grism which covers the range between 5100 and 10000 AA with a resolution of R~800.
The acquisition image was obtained under good conditions with a seeing of 0.8". The afterglow is clearly detected although it shows a strong decay in brightness with respect to previous detections (Guidorzi et al. GCN18816, Saito et al. GCN 18817, Yurkov et al. GCN 18820, Xin et al. 18823). As compared to USNO-B1.0 stars we measure a magnitude of i(Vega)=22.6, roughly equivalent to i(AB)=23.0.
The combined spectrum shows a clear continuum over the complete range with only one prominent absorption feature centred at 5889 AA, with an equivalent width of ~30 AA. There are also tentative absorptions features at ~5300 and ~5340 AA. There is no drop bluewards of the 5889 AA feature which could otherwise be suggestive of a weak Ly-alpha at z=3.84. At a redshift of 2.80, the features could be consistent with CIV and the two SiIV, respectively. We are not able to establish a convincing solution for the redshift based on this evidence.
GCN Circular #18833
GRB 160104A: Nishi-Harima MINT Observations
K. Morihana. J. Takahashi, Y. Takagi, S. Honda, T. Ohshima, and Y. Itoh (Univ. of Hyogo), report on behalf of Nayuta team and OISTER collaboration:
We observed the field of GRB 160104A (Melandri et al. GCN 18815) with Multiband Imager for Nayuta Telescope (MINT) attached to the Nayuta 2-m telescope at the Nishi-Harima Astronomical Observatory.
The observations were started at 12:01 UT on 2016-01-4 (~35 minuets after the burst). We detected the optical afterglow in Rc band within the error circle of Swift/XRT.
Photometric results of our observations are shown below. We used nearby NOMAD catalogue stars for the photometric calibration.
```
# MID-UT Tmid-T0 T-EXP Rc_mag
----------------------------------------------------------------------
12:37:32 0.0509 4200s 21.6+/-0.5
----------------------------------------------------------------------
Tmid-T0: Elapsed time after the burst (day)
T-EXP: Total Exposure time (seconds)
```
GCN Circular #18841
T.Fujiwara, Y.Saito, T. Yoshii, Y. Yano, Y. Tachibana, Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 160104A (A. Melandri et al., GCN Circular #18815) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2016-01-04 11:24:56 UT (46 sec after the burst) and we detected the optical counterpart in Rc and Ic band. The measured magnitudes were listed as follows.
We obtained following results for the magnitudes.
```
T0+[sec]    MID-UT      T-EXP[sec]         g'              Rc                      Ic
-------------------------------------------------------------------------------------------------------
382            11:38:50        900                  > 20.6         18.9 +/- 0.1      18.3 +/- 0.2
13473         16:03:30        5880                 > 21.3         20.2 +/- 0.2      19.5 +/- 0.3
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used GSC2.3 catalog for flux calibration.
GCN Circular #18856
F.E. Marshall (NASA/GSFC) and A. Melandri (INAF-OAB) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160104A 85 s after the BAT trigger (Melandri et al., GCN Circ. 18815). A fading source consistent with the XRT position (Beardmore et al. GCN Circ. 18821) and the optical afterglow position (Guidorzi et al. GCN Circ. 18816) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
    RA  (J2000) =  05:07:11.05 =  76.79603 (deg.)
    Dec (J2000) =  11:19:25.5  =  11.32375 (deg.)
```
with an estimated uncertainty of 0.64 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               85          235          141         20.48 +/- 0.22
white             1180         1893           94        >20.5
v                  627         1252           78         18.92 +/- 0.32
b                  553         1869          136        >19.8
u                  297         1843          363        >20.5
w1                 677         1819          136        >20.1
m2                 825         5587          203        >20.1
w2                 602         5249          333        >20.5
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.26 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #18890
E. Mazaeva (IKI), E. Chornaya (UAFO), A. Matkin (UAFO, ISON), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 160104A (Melandri et al., GCN 18815) with SANTEL-650 (0.65m) telescope of UAFO/ISON-Ussuriysk observatory starting on 2016-01-04 (UT) 12:21:43. We obtained 60 unfiltered images of 60 s exposure. We clearly detect optical afterglow (Guidorzi et al., GCN 18816) and preliminary photometry of a combined image is following
```
Date       UT start  t-T0  Filter  Exp.    OT   OT_err U_limit (3sigma)
                      (mid, days)   (s)

2016-01-04 12:21:43  0.0635 none    59*60  20.45 0.12  22.3
```
The photometry is based on nearby USNO-B1.0 stars:
```
USNO-B1.0_id R2
1013-0049708 15.14
1013-0049721 14.90
1013-0049703 16.30
1013-0049714 17.12
```
We also note the presence of a source 11" South-East of m = 20.60 +/- 0.15.

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Jochen Greiner, last update: 18-Jan-2016 [Disclaimer]