Gamma-ray Burst 160408A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:26:05 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     682059,   Seg_Num: 0
GRB_RA:          122.557d {+08h 10m 14s} (J2000),
                 122.988d {+08h 11m 57s} (current),
                 121.222d {+08h 04m 53s} (1950)
GRB_DEC:         +71.140d {+71d 08' 25"} (J2000),
                 +71.091d {+71d 05' 28"} (current),
                 +71.287d {+71d 17' 14"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2451 [cnts]    Image_Peak=176 [image_cnts]
TRIGGER_DUR:     0.384 [sec] 
TRIGGER_INDEX:   482     E_range: 50-350 keV
BKG_INTEN:       22481 [cnts]
BKG_TIME:        23127.90 SOD {06:25:27.90} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17486 TJD;    99 DOY;   16/04/08
GRB_TIME:        23143.77 SOD {06:25:43.77} UT
GRB_PHI:         -25.34 [deg]
GRB_THETA:        45.86 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     38.96 [sigma]
IMAGE_SIGNIF:    11.30 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +3  +1  +0  +0  -3  +0 
SUN_POSTN:        17.40d {+01h 09m 36s}   +7.39d {+07d 23' 09"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.36d {+01h 57m 26s}   +8.57d {+08d 34' 01"}
MOON_DIST:        83.07 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.94, 31.90 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      105.52, 49.45 [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 = 128.38,16.35 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(6.0<100sec) coincident with the CALET event (trignum=1144131613).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:26:21 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     481789547
GRB_RA:          131.950d {+08h 47m 48s} (J2000),
                 132.389d {+08h 49m 33s} (current),
                 130.585d {+08h 42m 20s} (1950)
GRB_DEC:         +73.800d {+73d 47' 60"} (J2000),
                 +73.739d {+73d 44' 21"} (current),
                 +73.984d {+73d 59' 01"} (1950)
GRB_ERROR:       2.56 [deg radius, statistical only]
DATA_SIGNIF:     21.70 [sigma]
DATA_INTERVAL:   0.512 [sec]
GRB_DATE:        17486 TJD;    99 DOY;   16/04/08
GRB_TIME:        23143.86 SOD {06:25:43.86} UT
GRB_PHI:          40.00 [deg]
GRB_THETA:         3.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4153 (Gnd S/W Version number)
SUN_POSTN:        17.40d {+01h 09m 36s}   +7.39d {+07d 23' 09"}
SUN_DIST:         89.65 [deg]   Sun_angle= -7.7 [hr] (East of Sun)
MOON_POSTN:       29.36d {+01h 57m 27s}   +8.57d {+08d 34' 04"}
MOON_DIST:        85.38 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      140.03, 33.96 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      108.05, 52.99 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn160408268/quicklook/glg_lc_medres34_bn160408268.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_481789547.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~4 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=682059).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:26:07 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      49
TRIGGER_NUM:     481789547
GRB_RA:          145.467d {+09h 41m 52s} (J2000),
                 145.943d {+09h 43m 46s} (current),
                 143.970d {+09h 35m 53s} (1950)
GRB_DEC:         +79.250d {+79d 15' 00"} (J2000),
                 +79.175d {+79d 10' 31"} (current),
                 +79.477d {+79d 28' 38"} (1950)
GRB_ERROR:       6.48 [deg radius, statistical plus systematic]
GRB_INTEN:       611 [cnts/sec]
DATA_SIGNIF:     17.90 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        17486 TJD;    99 DOY;   16/04/08
GRB_TIME:        23143.86 SOD {06:25:43.86} UT
GRB_PHI:         300.00 [deg]
GRB_THETA:         5.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.44
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      95%  GRB
2nd_MOST_LIKELY:   4%  Generic Transient
DETECTORS:       1,1,0, 1,0,1, 1,1,0, 1,0,0, 0,0,
SUN_POSTN:        17.40d {+01h 09m 36s}   +7.39d {+07d 23' 09"}
SUN_DIST:         89.42 [deg]   Sun_angle= -8.6 [hr] (East of Sun)
MOON_POSTN:       29.36d {+01h 57m 26s}   +8.57d {+08d 34' 01"}
MOON_DIST:        86.38 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      132.47, 34.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      107.48, 59.24 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2016/bn160408268/quicklook/glg_lc_medres34_bn160408268.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 225.38,25.00 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=682059).

GCN NOTICE

 
TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Fri 08 Apr 16 06:26:34 UT 
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    7441,   Sub_Num: 0
GRB_INTEN:      10.09 [sigma]
GRB_TIME:       23143.15 SOD {06:25:43.15} UT
GRB_DATE:       17486 TJD;    99 DOY;   16/04/08
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=0.8000 and Time_Error=0.4000.
COMMENTS:
COMMENTS:       NOTE: This SPIACS event is temporally(0.0<100sec) coincident with the   FERMI_GBM event (trignum=481789547). 
COMMENTS:
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2016-04/2016-04-08T06-25-43.1258-31470-43920-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:27:28 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.581d {+08h 10m 19s} (J2000)
POINT_DEC:       +71.135d {+71d 08' 05"} (J2000)
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23238.58 SOD {06:27:18.58} UT,   94.8 [sec] since BAT Trigger Time
COUNTS:          4    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:     Fri 08 Apr 16 06:29:37 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     682059,   Seg_Num: 0
GRB_RA:          122.557d {+08h 10m 14s} (J2000),
                 122.988d {+08h 11m 57s} (current),
                 121.222d {+08h 04m 53s} (1950)
GRB_DEC:         +71.140d {+71d 08' 25"} (J2000),
                 +71.091d {+71d 05' 28"} (current),
                 +71.287d {+71d 17' 14"} (1950)
GRB_DATE:        17486 TJD;    99 DOY;   16/04/08
GRB_TIME:        23143.77 SOD {06:25:43.77} UT
TRIGGER_INDEX:   482
GRB_PHI:         -25.34 [deg]
GRB_THETA:        45.86 [deg]
DELTA_TIME:      13.00 [sec]
TRIGGER_DUR:     0.384 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     38.96 [sigma]
IMAGE_SIGNIF:    11.30 [sigma]
LC_URL:          sw00682059000msb.lc
SUN_POSTN:        17.40d {+01h 09m 37s}   +7.39d {+07d 23' 12"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.39d {+01h 57m 35s}   +8.58d {+08d 34' 39"}
MOON_DIST:        83.05 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.94, 31.90 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      105.52, 49.45 [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 = 128.38,16.35 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:30:17 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.580d {+08h 10m 19s} (J2000)
POINT_DEC:       +71.135d {+71d 08' 05"} (J2000)
POINT_ROLL:      286.745d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23242.14 SOD {06:27:22.14} UT,   98.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.826
N_STARS:         27
X_OFFSET:        560 [pixels]
Y_OFFSET:        554 [pixels]
X_MAX:           1519 [pixels]
Y_MAX:           1513 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00682059000msufc0098.fits
SUN_POSTN:        17.40d {+01h 09m 37s}   +7.39d {+07d 23' 12"}
SUN_DIST:         87.99 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.40d {+01h 57m 36s}   +8.58d {+08d 34' 46"}
MOON_DIST:        83.05 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.94, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.53, 49.45 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:30:51 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.580d {+08h 10m 19s} (J2000)
POINT_DEC:       +71.135d {+71d 08' 05"} (J2000)
POINT_ROLL:      286.745d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23242.14 SOD {06:27:22.14} UT,   98.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.826
N_STARS:         27
X_OFFSET:        560 [pixels]
Y_OFFSET:        554 [pixels]
X_MAX:           1519 [pixels]
Y_MAX:           1513 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00682059000msufc0098.fits
SUN_POSTN:        17.40d {+01h 09m 37s}   +7.39d {+07d 23' 13"}
SUN_DIST:         87.99 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.41d {+01h 57m 38s}   +8.58d {+08d 34' 52"}
MOON_DIST:        83.05 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.94, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.53, 49.45 [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:     Fri 08 Apr 16 06:31:19 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     682059,   Seg_Num: 0
GRB_RA:          122.6254d {+08h 10m 30.09s} (J2000),
                 123.0561d {+08h 12m 13.47s} (current),
                 121.2910d {+08h 05m 09.83s} (1950)
GRB_DEC:         +71.1278d {+71d 07' 40.0"} (J2000),
                 +71.0787d {+71d 04' 43.2"} (current),
                 +71.2752d {+71d 16' 30.6"} (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:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23249.00 SOD {06:27:29.00} UT,   105.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        17.40d {+01h 09m 37s}   +7.39d {+07d 23' 13"}
SUN_DIST:         88.00 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.41d {+01h 57m 39s}   +8.58d {+08d 34' 57"}
MOON_DIST:        83.06 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.93 [deg] galactic lon,lat of the burst
ECL_COORDS:      105.56, 49.45 [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:     Fri 08 Apr 16 06:31:43 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.580d {+08h 10m 19s} (J2000)
POINT_DEC:       +71.135d {+71d 08' 05"} (J2000)
ROLL:            286.745d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23242.14 SOD {06:27:22.14} UT,   98.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     481789658
X_OFFSET:        879 [pixels]
Y_OFFSET:        873 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1033
BINNING_INDEX:   1
IM_URL:          sw00682059000msuni0115.fits
SUN_POSTN:        17.40d {+01h 09m 37s}   +7.39d {+07d 23' 14"}
SUN_DIST:         87.99 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.42d {+01h 57m 40s}   +8.58d {+08d 35' 01"}
MOON_DIST:        83.04 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.94, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.53, 49.45 [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:     Fri 08 Apr 16 06:32:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.580d {+08h 10m 19s} (J2000)
POINT_DEC:       +71.135d {+71d 08' 05"} (J2000)
ROLL:            286.745d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23242.14 SOD {06:27:22.14} UT,   98.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     481789658
X_OFFSET:        879 [pixels]
Y_OFFSET:        873 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1033
BINNING_INDEX:   1
IM_URL:          sw00682059000msuni0115.fits
SUN_POSTN:        17.40d {+01h 09m 37s}   +7.39d {+07d 23' 14"}
SUN_DIST:         87.99 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.42d {+01h 57m 41s}   +8.58d {+08d 35' 05"}
MOON_DIST:        83.04 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.94, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.53, 49.45 [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:     Fri 08 Apr 16 06:37:38 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 54"} (J2000)
POINT_ROLL:      286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23454.70 SOD {06:30:54.70} UT,   310.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.079
N_STARS:         41
X_OFFSET:        320 [pixels]
Y_OFFSET:        314 [pixels]
X_MAX:           1759 [pixels]
Y_MAX:           1753 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00682059000msufc0310.fits
SUN_POSTN:        17.41d {+01h 09m 38s}   +7.39d {+07d 23' 19"}
SUN_DIST:         87.99 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.48d {+01h 57m 54s}   +8.60d {+08d 36' 04"}
MOON_DIST:        83.01 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:37:54 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 54"} (J2000)
POINT_ROLL:      286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23454.70 SOD {06:30:54.70} UT,   310.9 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.079
N_STARS:         41
X_OFFSET:        320 [pixels]
Y_OFFSET:        314 [pixels]
X_MAX:           1759 [pixels]
Y_MAX:           1753 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00682059000msufc0310.fits
SUN_POSTN:        17.41d {+01h 09m 38s}   +7.39d {+07d 23' 20"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.48d {+01h 57m 55s}   +8.60d {+08d 36' 07"}
MOON_DIST:        83.01 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [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:     Fri 08 Apr 16 06:38:02 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     682059,   Seg_Num: 0
GRB_RA:          122.6235d {+08h 10m 29.64s} (J2000),
                 123.0542d {+08h 12m 13.01s} (current),
                 121.2891d {+08h 05m 09.37s} (1950)
GRB_DEC:         +71.1283d {+71d 07' 41.8"} (J2000),
                 +71.0792d {+71d 04' 45.0"} (current),
                 +71.2757d {+71d 16' 32.4"} (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:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23249.00 SOD {06:27:29.00} UT,   105.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        17.41d {+01h 09m 38s}   +7.39d {+07d 23' 20"}
SUN_DIST:         88.00 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.48d {+01h 57m 55s}   +8.60d {+08d 36' 09"}
MOON_DIST:        83.02 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.93 [deg] galactic lon,lat of the burst
ECL_COORDS:      105.56, 49.45 [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:     Fri 08 Apr 16 06:39:02 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 54"} (J2000)
ROLL:            286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23454.70 SOD {06:30:54.70} UT,   310.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     481789870
X_OFFSET:        879 [pixels]
Y_OFFSET:        873 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1033
BINNING_INDEX:   1
IM_URL:          sw00682059000msuni0327.fits
SUN_POSTN:        17.41d {+01h 09m 38s}   +7.39d {+07d 23' 21"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.49d {+01h 57m 58s}   +8.61d {+08d 36' 19"}
MOON_DIST:        83.00 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [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:     Fri 08 Apr 16 06:39:18 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 54"} (J2000)
ROLL:            286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  23454.70 SOD {06:30:54.70} UT,   310.9 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     481789870
X_OFFSET:        879 [pixels]
Y_OFFSET:        873 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1033
BINNING_INDEX:   1
IM_URL:          sw00682059000msuni0327.fits
SUN_POSTN:        17.41d {+01h 09m 38s}   +7.39d {+07d 23' 21"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.49d {+01h 57m 58s}   +8.61d {+08d 36' 22"}
MOON_DIST:        83.00 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [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 #19260
P.A. Evans (U Leicester), S. D. Barthelmy (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 06:25:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160408A (trigger=682059). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 122.557, +71.140, which is
```
   RA(J2000)  =  08h 10m 14s
   Dec(J2000) = +71d 08' 25"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 0.5 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 06:27:18.5 UT, 94.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 122.6235, 71.1284 which is equivalent to:
```
   RA(J2000)  = 08h 10m 29.64s
   Dec(J2000) = +71d 07' 42.3"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 87 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (4.18 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9 (+3.04/-2.61) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 98 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 0.03.
Burst Advocate for this burst is P.A. Evans (pae9 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:43:03 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 55"} (J2000)
POINT_ROLL:      286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  24009.13 SOD {06:40:09.13} UT,   865.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.856
N_STARS:         86
X_OFFSET:        320 [pixels]
Y_OFFSET:        314 [pixels]
X_MAX:           1759 [pixels]
Y_MAX:           1753 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00682059000msufc0865.fits
SUN_POSTN:        17.41d {+01h 09m 39s}   +7.39d {+07d 23' 24"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.53d {+01h 58m 08s}   +8.62d {+08d 37' 02"}
MOON_DIST:        82.98 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 08 Apr 16 06:43:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 55"} (J2000)
POINT_ROLL:      286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  24009.13 SOD {06:40:09.13} UT,   865.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.856
N_STARS:         86
X_OFFSET:        320 [pixels]
Y_OFFSET:        314 [pixels]
X_MAX:           1759 [pixels]
Y_MAX:           1753 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00682059000msufc0865.fits
SUN_POSTN:        17.41d {+01h 09m 39s}   +7.39d {+07d 23' 25"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.54d {+01h 58m 09s}   +8.62d {+08d 37' 06"}
MOON_DIST:        82.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [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:     Fri 08 Apr 16 06:44:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 55"} (J2000)
ROLL:            286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  24009.13 SOD {06:40:09.13} UT,   865.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     481790425
X_OFFSET:        879 [pixels]
Y_OFFSET:        873 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1033
BINNING_INDEX:   1
IM_URL:          sw00682059000msuni0882.fits
SUN_POSTN:        17.41d {+01h 09m 39s}   +7.39d {+07d 23' 26"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.55d {+01h 58m 12s}   +8.62d {+08d 37' 21"}
MOON_DIST:        82.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [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:     Fri 08 Apr 16 06:44:22 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     682059,   Seg_Num: 0
POINT_RA:        122.583d {+08h 10m 20s} (J2000)
POINT_DEC:       +71.132d {+71d 07' 55"} (J2000)
ROLL:            286.747d
IMG_START_DATE:  17486 TJD;    99 DOY;   16/04/08
IMG_START_TIME:  24009.13 SOD {06:40:09.13} UT,   865.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     481790425
X_OFFSET:        879 [pixels]
Y_OFFSET:        873 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       1033
BINNING_INDEX:   1
IM_URL:          sw00682059000msuni0882.fits
SUN_POSTN:        17.41d {+01h 09m 39s}   +7.39d {+07d 23' 26"}
SUN_DIST:         87.98 [deg]   Sun_angle= -7.0 [hr] (East of Sun)
MOON_POSTN:       29.55d {+01h 58m 11s}   +8.62d {+08d 37' 16"}
MOON_DIST:        82.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      143.95, 31.91 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      105.54, 49.45 [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 Circular #19261
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1293 s of XRT Photon Counting mode data and 2 UVOT images for GRB 160408A, 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 = 122.62470, +71.12831 which is equivalent to:
```
RA (J2000): 08h 10m 29.93s
Dec (J2000): +71d 07' 41.9"
```
with an uncertainty of 1.9 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 #19262
A.J. Levan (U. Warwick) and N.R. Tanvir (U. Leicester) report for a large r collaboration:
We observed the location of the short GRB 160408A (Evans et al. GCN 19260) with Gemini-North and GMOS. Observations were taken in the r-band, starting at 07:23 UT, approximately 58 minutes after the burst. Several objects are present in the field close to the refined XRT position (Osborne et al. GCN 19261). The closest objects are a compact source (A) and a more extended galaxy (B). The locations of these sources are:
```
Source A:
RA(J2000) 08h 10m 29.81s
DEC(J2000) 71d 07=E2=80=99 43.7=E2=80=9D=20

Source B:
RA(J2000) 08h 10m 29.32s
DEC(J2000) 71d 07=E2=80=99 40.5=E2=80=9D
```
with an uncertainty of approximately 0.3=E2=80=9D in each co-ordinate. Conditions were not photometric at the time of the observations, but comparison with USNO-B1 sources in the field of view suggests that source A has a magnitude of r~24.5, source B is approximately a magnitude brighter.
We thank the Gemini staff for the rapid execution of these observations.
GCN Circular #19263
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), P.A. Evans (U Leicester), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-120 to T+302 sec from the recent telemetry downlinks, we report further analysis of BAT GRB 160408A (trigger #682059) (Evans, et al., GCN Circ. 19260). The BAT ground-calculated position is RA, Dec = 122.561, 71.128 deg, which is
```
   RA(J2000)  =  08h 10m 14.6s 
   Dec(J2000) = +71d 07' 40.0" 
```
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%.
The mask-weighted light curve starts at ~T0, peaks at ~T+0.1 sec, and ends at ~T+0.4 sec. T90 (15-350 keV) is 0.32 +- 0.04 sec (estimated error including systematics).
The time-averaged spectrum from T+0.02 to T+0.37 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.85 +- 0.25. The fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.30 sec in the 15-150 keV band is 2.1 +- 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/682059/BA/
We note that this burst was detected by Fermi-GBM, CALET-GBM, Swift-BAT, and INTEGRAL-SPIACS.
GCN Circular #19265
O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team:
"At 06:25:43.86 UT on the 8th of April 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160408A (trigger 481789547 / 160408268), which was also detected by Swift (Evans et al. 2008, GCN 19620). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time using the Swift XRT position is about 7 degrees.
The GBM light curve consists of two bright, short emission episodes, with a duration (T90) of about 0.9 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.384 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.76 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 914 +/- 184 keV.
The event fluence (10-1000 keV) in this time interval is (1.25 +/- 0.08)E-06 erg/cm^2. The 64 ms peak photon flux measured starting from T0+0 s in the 10-1000 keV band, is 12.4 +/- 1.4 ph/s/cm^2.
A Band function fits the spectrum equally well, with Epeak = 765 +/- 198 keV, alpha = -0.70 +/- 0.12, and beta = -2.27 +/- 0.41.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN Circular #19266
J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for GRB 160408A (Evans et al. GCN Circ. 19260), from 103 s to 23.4 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 19261).
The light curve can be modelled with a power-law decay with a decay index of alpha=1.3 (+/-0.3).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.1 (+/-0.4). The best-fitting absorption column is 1.6 (+1.4, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 4.2 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (4.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.6 (+1.4, -1.1) x 10^21 cm^-2
Galactic foreground: 4.2 x 10^20 cm^-2
Excess significance: 1.9 sigma
Photon index:	     2.1 (+/-0.4)
```
If the light curve continues to decay with a power-law decay index of 1.3, the count rate at T+24 hours will be 8.4 x 10^-5 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.8 x 10^-15 (3.8 x 10^-15) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00682059.
This circular is an official product of the Swift-XRT team.
GCN Circular #19267
M. H. Siegel (PSU) and P. A. Evans (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160408A 98 s after the BAT trigger (Evans et al., GCN Circ. 19260). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 19261) or the possible optical counterparts (Levan et al., GCN Circ. 19262) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC            98          248          147         >21.0
u_FC               311          561          246         >19.7
white               98         1365          373         >21.8
v                  641         1414           97         >19.4
b                  566         1340           78         >19.6
u                  311         1316          304         >19.9
w1                 691         1291           58         >19.5
m2                 838         1092           39         >18.8
w2                 617         1390           97         >19.9
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #19268
J. I. Avalos, N. P. Plaza, M. Blunck, L. Lalounta, E. Komucyeya, S. Schmidl, S. Klose, D. A. Kann, A. Nicuesa Guelbenzu, and F. Ludwig (TLS Tautenburg) report:
We observed the field of the short GRB 160408A (Evans et al., GCN 19260) with the Tautenburg 1.34-m Schmidt telescope at as mid-time of about 15.3 hrs after the GRB trigger, at a mean airmass of 1.2. We obtained 10 x 300 sec exposures in the Ic band.
Inside the 1".9 enhanced XRT error circle (Osborne et al.,GCN 19261), we do not detect the possible optical counterparts reported by Levan et al. (GCN Circ. 19262). We estimate a preliminary upper limit of Ic > 21.3 mag, calibrated against USNO-B1 field stars.
GCN Circular #19269
A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), A. Cucchiara (GSFC/STScI), W. Fong (Arizona), D. Perley (DARK/NBI) report for a larger collaboration:
=E2=80=9CWe obtained a second epoch of Gemini-North observations of the short GRB 160408A (Evans et al. GCN 19260, Palmer et al. GCN 19263) on 9 April 2016, approximately 22 hours after our previous observations. Although the images are somewhat shallower than the first epoch, the previously identified source A (Levan & Tanvir GCN 19262) has clearly faded by at least a magnitude between the two epochs, and is not detected in our new imaging. This confirms it as the optical afterglow of GRB 160408A.=E2=80=9D
GCN Circular #19270
W.-M. Yi, J. Mao and J.-M. Bai (YNAO) report:
We observed the field of GRB 160408A (Evans et al., GCN 19260) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. Observations began from 15:10:26 UT, Apr. 8th, 2016, about 9 hours after the trigger. We did not detect any source at the afterglow position (Levan et al. GCN 19269) down to a limit of R~23.3 mag.
GCN Circular #19294
W. Fong (University of Arizona) reports:
"We observed the field of the short-duration GRB 160408A (Evans et al., GCN 19260) with the Karl G. Jansky Very Large Array (VLA) beginning on 2016 Apr 8.889 UT (14.91 hr post-burst) at a mean frequency of 6.0 GHz. In 1 hour of observations, we do not detect any radio source within or around the enhanced XRT position (Osborne et al., GCN 19261) or the optical afterglow position (Levan et al., GCNs 19262, 19269) to a 3-sigma limit of 21.5 microJy. We therefore place a 3-sigma limit of 21.5 microJy on the radio afterglow of GRB 160408A at 14.91 hr after the burst.
We thank the VLA staff for quickly executing these observations."
GCN Circular #19297
W. Ishizaki (ICRR), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) and the CALET collaboration:
The short-duration GRB 160408A (Swift, Evans et al. GCN Circ. 19260; Fermi-GBM, Roberts et al. GCN Circ. 19265; INTEGRAL-ACS, Trigger #7441) triggered the CALET Gamma-Ray Burst Monitor (CGBM) at 6:25:37.4 on 8 April 2016. The burst signal was detected by all CGBM instruments.
The light curve of the SGM shows a single peak. The emission starts at T0+6.4 sec, peaks at T0+6.5 sec and ends at T0+7.1 sec. The T90 duration measured by the SGM data is 0.38 +- 0.18 sec (40-1000 keV).
The CGBM data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #19508
K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)
The AMI Large Array robotically triggered on the Swift alert for GRB 160408A (Evans et al., GCN 19260) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 Apr 08.61, Apr 09.77, Apr 13.87, Apr 15.74, and Apr 19.78 (UT) do not reveal any radio source at the XRT location (Osborne et al., GCN 19261), with 3sigma upper limits of 117 uJy, 144 uJy, 102 uJy, 204 uJy, and 145 uJy respectively.
We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.
photometric redshift z = z = 1.90 +0.38 -0.53
of host-galaxy: A. E. Nugent et al. 2022, ApJ, 940, 57

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Jochen Greiner, last update: 12-Jan-2023 [Disclaimer]