Gamma-ray Burst 160327A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:16:22 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     680655,   Seg_Num: 0
GRB_RA:          146.689d {+09h 46m 45s} (J2000),
                 146.965d {+09h 47m 52s} (current),
                 145.835d {+09h 43m 20s} (1950)
GRB_DEC:         +54.017d {+54d 01' 00"} (J2000),
                 +53.941d {+53d 56' 28"} (current),
                 +54.248d {+54d 14' 54"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4173 [cnts]    Image_Peak=183 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   137     E_range: 15-50 keV
BKG_INTEN:       26681 [cnts]
BKG_TIME:        33351.96 SOD {09:15:51.96} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17474 TJD;    87 DOY;   16/03/27
GRB_TIME:        33367.70 SOD {09:16:07.70} UT
GRB_PHI:         -85.77 [deg]
GRB_THETA:        16.50 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.08 [sigma]
IMAGE_SIGNIF:    7.60 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +1  -2  +0  +0 +41  +0 
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 49' 60"}
SUN_DIST:        114.40 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.02d {+15h 12m 04s}  -13.21d {-13d 12' 23"}
MOON_DIST:        95.48 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.34, 46.98 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      128.47, 37.88 [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 = 181.71,16.20 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:17:42 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     680655,   Seg_Num: 0
GRB_RA:          146.7042d {+09h 46m 49.00s} (J2000),
                 146.9802d {+09h 47m 55.24s} (current),
                 145.8499d {+09h 43m 23.98s} (1950)
GRB_DEC:         +54.0123d {+54d 00' 44.2"} (J2000),
                 +53.9366d {+53d 56' 11.8"} (current),
                 +54.2439d {+54d 14' 37.9"} (1950)
GRB_ERROR:       5.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.01e-09 [erg/cm2/sec]
GRB_SIGNIF:      7.07 [sigma]
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33428.20 SOD {09:17:08.20} UT,   60.5 [sec] since BAT Trigger Time
TAM[0-3]:        327.69 237.20 261.72 243.76
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 01"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.03d {+15h 12m 06s}  -13.21d {-13d 12' 31"}
MOON_DIST:        95.48 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.34, 46.99 [deg] galactic lon,lat of the burst
ECL_COORDS:      128.48, 37.88 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.59 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:17:51 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     680655,   Seg_Num: 0
GRB_RA:          146.7042d {+09h 46m 49.0s} (J2000),
                 146.9802d {+09h 47m 55.2s} (current),
                 145.8499d {+09h 43m 23.9s} (1950)
GRB_DEC:         +54.0123d {+54d 00' 44.2"} (J2000),
                 +53.9366d {+53d 56' 11.8"} (current),
                 +54.2439d {+54d 14' 37.9"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       50 [cnts]
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33428.20 SOD {09:17:08.20} UT,   60.5 [sec] since BAT Trigger Time
CENTROID_X:      295.75,  raw= 296  [pixels]
CENTROID_Y:      297.85,  raw= 298  [pixels]
ROLL:            315.45 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   0.12
GRB_POS_XRT_Z:   -22.50
IMAGE_URL:       sw00680655000msxps_rw.img
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 01"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.03d {+15h 12m 07s}  -13.21d {-13d 12' 32"}
MOON_DIST:        95.48 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.34, 46.99 [deg] galactic lon,lat of the burst
ECL_COORDS:      128.48, 37.88 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:17:56 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     680655,   Seg_Num: 0
GRB_RA:          146.7042d {+09h 46m 49.0s} (J2000),
                 146.9802d {+09h 47m 55.2s} (current),
                 145.8499d {+09h 43m 23.9s} (1950)
GRB_DEC:         +54.0123d {+54d 00' 44.2"} (J2000),
                 +53.9366d {+53d 56' 11.8"} (current),
                 +54.2439d {+54d 14' 37.9"} (1950)
GRB_ERROR:       5.4 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       50 [cnts]
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33428.20 SOD {09:17:08.20} UT,   60.5 [sec] since BAT Trigger Time
CENTROID_X:      295.75,  raw= 296  [pixels]
CENTROID_Y:      297.85,  raw= 298  [pixels]
ROLL:            315.45 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   0.12
GRB_POS_XRT_Z:   -22.50
IMAGE_URL:       sw00680655000msxps_rw.img
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 01"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.03d {+15h 12m 07s}  -13.21d {-13d 12' 33"}
MOON_DIST:        95.48 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.34, 46.99 [deg] galactic lon,lat of the burst
ECL_COORDS:      128.48, 37.88 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:19:48 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     680655,   Seg_Num: 0
GRB_RA:          146.689d {+09h 46m 45s} (J2000),
                 146.965d {+09h 47m 52s} (current),
                 145.835d {+09h 43m 20s} (1950)
GRB_DEC:         +54.017d {+54d 01' 00"} (J2000),
                 +53.941d {+53d 56' 28"} (current),
                 +54.248d {+54d 14' 54"} (1950)
GRB_DATE:        17474 TJD;    87 DOY;   16/03/27
GRB_TIME:        33367.70 SOD {09:16:07.70} UT
TRIGGER_INDEX:   137
GRB_PHI:         -85.77 [deg]
GRB_THETA:        16.50 [deg]
DELTA_TIME:      26.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     12.08 [sigma]
IMAGE_SIGNIF:    7.60 [sigma]
LC_URL:          sw00680655000msb.lc
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 03"}
SUN_DIST:        114.40 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.04d {+15h 12m 11s}  -13.21d {-13d 12' 45"}
MOON_DIST:        95.50 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.34, 46.98 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      128.47, 37.88 [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 = 181.71,16.20 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:20:20 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.712d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.008d {+54d 00' 28"} (J2000)
POINT_ROLL:      315.446d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33438.55 SOD {09:17:18.55} UT,   70.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.704
N_STARS:         34
X_OFFSET:        526 [pixels]
Y_OFFSET:        526 [pixels]
X_MAX:           1485 [pixels]
Y_MAX:           1485 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00680655000msufc0070.fits
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 04"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.05d {+15h 12m 12s}  -13.21d {-13d 12' 48"}
MOON_DIST:        95.49 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 46.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:20:39 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.712d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.008d {+54d 00' 28"} (J2000)
POINT_ROLL:      315.446d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33438.55 SOD {09:17:18.55} UT,   70.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.704
N_STARS:         34
X_OFFSET:        526 [pixels]
Y_OFFSET:        526 [pixels]
X_MAX:           1485 [pixels]
Y_MAX:           1485 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00680655000msufc0070.fits
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 04"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.05d {+15h 12m 12s}  -13.21d {-13d 12' 50"}
MOON_DIST:        95.49 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 46.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:21:58 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.712d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.008d {+54d 00' 28"} (J2000)
ROLL:            315.446d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33438.55 SOD {09:17:18.55} UT,   70.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     480763054
X_OFFSET:        846 [pixels]
Y_OFFSET:        846 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1006
Y_GRB_POS:       1006
BINNING_INDEX:   1
IM_URL:          sw00680655000msuni0087.fits
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 05"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.06d {+15h 12m 15s}  -13.22d {-13d 12' 59"}
MOON_DIST:        95.50 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 46.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:22:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.712d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.008d {+54d 00' 28"} (J2000)
ROLL:            315.446d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33438.55 SOD {09:17:18.55} UT,   70.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     480763054
X_OFFSET:        846 [pixels]
Y_OFFSET:        846 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1006
Y_GRB_POS:       1006
BINNING_INDEX:   1
IM_URL:          sw00680655000msuni0087.fits
SUN_POSTN:         6.56d {+00h 26m 14s}   +2.83d {+02d 50' 05"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.06d {+15h 12m 15s}  -13.22d {-13d 13' 00"}
MOON_DIST:        95.50 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 46.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:27:54 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 24"} (J2000)
POINT_ROLL:      315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33651.47 SOD {09:20:51.47} UT,   283.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.537
N_STARS:         24
X_OFFSET:        526 [pixels]
Y_OFFSET:        526 [pixels]
X_MAX:           1485 [pixels]
Y_MAX:           1485 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00680655000msufc0283.fits
SUN_POSTN:         6.56d {+00h 26m 15s}   +2.84d {+02d 50' 11"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.11d {+15h 12m 27s}  -13.23d {-13d 13' 37"}
MOON_DIST:        95.54 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:28:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 24"} (J2000)
POINT_ROLL:      315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33651.47 SOD {09:20:51.47} UT,   283.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.537
N_STARS:         24
X_OFFSET:        526 [pixels]
Y_OFFSET:        526 [pixels]
X_MAX:           1485 [pixels]
Y_MAX:           1485 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00680655000msufc0283.fits
SUN_POSTN:         6.56d {+00h 26m 15s}   +2.84d {+02d 50' 11"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.11d {+15h 12m 27s}  -13.23d {-13d 13' 39"}
MOON_DIST:        95.54 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:28:18 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     680655,   Seg_Num: 0
GRB_RA:          146.7018d {+09h 46m 48.43s} (J2000),
                 146.9778d {+09h 47m 54.67s} (current),
                 145.8475d {+09h 43m 23.40s} (1950)
GRB_DEC:         +54.0131d {+54d 00' 47.1"} (J2000),
                 +53.9374d {+53d 56' 14.7"} (current),
                 +54.2447d {+54d 14' 40.7"} (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:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33503.00 SOD {09:18:23.00} UT,   135.3 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:         6.56d {+00h 26m 15s}   +2.84d {+02d 50' 11"}
SUN_DIST:        114.40 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.11d {+15h 12m 27s}  -13.23d {-13d 13' 40"}
MOON_DIST:        95.55 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.34, 46.99 [deg] galactic lon,lat of the burst
ECL_COORDS:      128.48, 37.88 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.11% < P(seren) < 0.58%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:29:05 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 24"} (J2000)
ROLL:            315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33651.47 SOD {09:20:51.47} UT,   283.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     480763267
X_OFFSET:        846 [pixels]
Y_OFFSET:        846 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1006
Y_GRB_POS:       1006
BINNING_INDEX:   1
IM_URL:          sw00680655000msuni0300.fits
SUN_POSTN:         6.56d {+00h 26m 15s}   +2.84d {+02d 50' 12"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.12d {+15h 12m 29s}  -13.23d {-13d 13' 45"}
MOON_DIST:        95.54 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:29:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 24"} (J2000)
ROLL:            315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  33651.47 SOD {09:20:51.47} UT,   283.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     480763267
X_OFFSET:        846 [pixels]
Y_OFFSET:        846 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1006
Y_GRB_POS:       1006
BINNING_INDEX:   1
IM_URL:          sw00680655000msuni0300.fits
SUN_POSTN:         6.56d {+00h 26m 16s}   +2.84d {+02d 50' 12"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.12d {+15h 12m 30s}  -13.23d {-13d 13' 47"}
MOON_DIST:        95.55 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:33:32 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 25"} (J2000)
POINT_ROLL:      315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  34231.82 SOD {09:30:31.82} UT,   864.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.739
N_STARS:         68
X_OFFSET:        286 [pixels]
Y_OFFSET:        286 [pixels]
X_MAX:           1725 [pixels]
Y_MAX:           1725 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00680655000msufc0864.fits
SUN_POSTN:         6.57d {+00h 26m 16s}   +2.84d {+02d 50' 17"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.16d {+15h 12m 38s}  -13.24d {-13d 14' 14"}
MOON_DIST:        95.57 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:33:50 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 25"} (J2000)
POINT_ROLL:      315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  34231.82 SOD {09:30:31.82} UT,   864.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.739
N_STARS:         68
X_OFFSET:        286 [pixels]
Y_OFFSET:        286 [pixels]
X_MAX:           1725 [pixels]
Y_MAX:           1725 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00680655000msufc0864.fits
SUN_POSTN:         6.57d {+00h 26m 16s}   +2.84d {+02d 50' 17"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.16d {+15h 12m 38s}  -13.24d {-13d 14' 16"}
MOON_DIST:        95.57 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:35:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 25"} (J2000)
ROLL:            315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  34231.82 SOD {09:30:31.82} UT,   864.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     480763847
X_OFFSET:        845 [pixels]
Y_OFFSET:        845 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1005
Y_GRB_POS:       1005
BINNING_INDEX:   1
IM_URL:          sw00680655000msuni0881.fits
SUN_POSTN:         6.57d {+00h 26m 16s}   +2.84d {+02d 50' 18"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.17d {+15h 12m 41s}  -13.24d {-13d 14' 24"}
MOON_DIST:        95.58 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 27 Mar 16 09:35:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     680655,   Seg_Num: 0
POINT_RA:        146.714d {+09h 46m 51s} (J2000)
POINT_DEC:       +54.007d {+54d 00' 25"} (J2000)
ROLL:            315.450d
IMG_START_DATE:  17474 TJD;    87 DOY;   16/03/27
IMG_START_TIME:  34231.82 SOD {09:30:31.82} UT,   864.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     480763847
X_OFFSET:        845 [pixels]
Y_OFFSET:        845 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1005
Y_GRB_POS:       1005
BINNING_INDEX:   1
IM_URL:          sw00680655000msuni0881.fits
SUN_POSTN:         6.57d {+00h 26m 16s}   +2.84d {+02d 50' 18"}
SUN_DIST:        114.41 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      228.17d {+15h 12m 42s}  -13.24d {-13d 14' 26"}
MOON_DIST:        95.58 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      161.35, 47.00 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      128.49, 37.88 [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 #19235
J. L. Racusin (NASA/GSFC), A. P. Beardmore (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team:
At 09:16:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160327A (trigger=680655). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 146.689, +54.017 which is
```
   RA(J2000) = 09h 46m 45s
   Dec(J2000) = +54d 01' 00"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 20 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~4 sec after the trigger.
The XRT began observing the field at 09:17:08.2 UT, 60.5 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 146.7019, 54.0131 which is equivalent to:
```
   RA(J2000)  = 09h 46m 48.45s
   Dec(J2000) = +54d 00' 47.0"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 30 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 1.17 x 10^20 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 1.01e-09 erg cm^-2 s^-1 (0.2-10 keV).
The prompt automatic UVOT analysis is not available at this time. However, there appears to be no credible afterglow candidate in the initial data.
Burst Advocate for this burst is J. L. Racusin (judith.racusin AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #19236
V. Zach Golkhou (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), and Vicki Toy (UMD) report:
We observed the field of GRB 160327A (Racusin, et al., GCN 19235) with the Reionization and Transients Infrared Camera (RATIR;www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2016/03 27.39 to 2016/03 27.41 UTC (3.6 minutes to 0.58 hours after the BAT trigger), obtaining a total of 0.36 hours exposure in the r and i bands and 0.15 hours exposure in the Z, Y, J, and H bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections:
```
r    21.78 +/- 0.13
i    19.68 +/- 0.02
Z   18.55 +/- 0.02
Y   17.75 +/- 0.01
J    17.56 +/- 0.01
H   16.74 +/- 0.01
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source is located at RA, Dec 9:46:48.54, +54:0:46.4 (J2000, +/-0.5").
Further observations are planned.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #19237
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 1040 s of XRT Photon Counting mode data and 2 UVOT images for GRB 160327A, 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 = 146.70264, +54.01278 which is equivalent to:
```
RA (J2000): 09h 46m 48.63s
Dec (J2000): +54d 00' 46.0"
```
with an uncertainty of 1.8 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #19238
P. D'Avanzo (INAF-OAB), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA) and J.L. Racusin report on behalf of the Swift-XRT team:
We have analysed 6.0 ks of XRT data for GRB 160327A (Racusin et al. GCN Circ. 19235), from 51 s to 22.1 ks after the BAT trigger. The data comprise 7 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 19237).
The light curve can be modelled with an initial power-law decay with an index of alpha=2.53 (+0.14, -0.13), followed by a break at T+291 s to an alpha of 0.59 (+/-0.06).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.97 (+0.15, -0.09). The best-fitting absorption column is consistent with the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.90 (+0.16, -0.15) and a best-fitting absorption column of 4.2 (+3.5, -3.0) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     4.2 (+3.5, -3.0) x 10^20 cm^-2
Galactic foreground: 1.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.90 (+0.16, -0.15)
```
If the light curve continues to decay with a power-law decay index of 0.59, the count rate at T+24 hours will be 0.023 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.7 x 10^-13 (8.5 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/00680655.
This circular is an official product of the Swift-XRT team.
GCN Circular #19239
L. M. McCauley (PSU) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160327A 71 s after the BAT trigger (Racusin et al., GCN Circ. 19235). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 19237) 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               71         221         147      >21.06
u_FC                  284         534         246      >20.52
white                  71        5902         535      >21.50
v                     613        6310         451      >19.66
b                     539        5702         254      >20.38
u                     283        6918         670      >20.66
uvw1                  662        6721         412      >20.21
uvm2                  637        1088          58      >18.49
uvw2                  589        1039          38      >18.61
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #19240
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160327A (trigger #680655) (Racusin, et al., GCN Circ. 19235). The BAT ground-calculated position is RA, Dec = 146.698, 54.018 deg which is
```
   RA(J2000)  =  09h 46m 47.5s
   Dec(J2000) = +54d 01' 04.0"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 82%.
BAT light curve shows a single peak starting around T-10 sec, peaking around T+5 sec and ending around T+22 sec. T90 (15-350 keV) is 28 +- 9 sec (estimated error including systematics).
The time-averaged spectrum from T-6.30 to T+42.80 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.84 +- 0.11. The fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+4.14 sec in the 15-150 keV band is 1.8 +- 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/680655/BA/
GCN Circular #19241
E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 160327A (Racusin et al., GCN 19235) with AZT-33IK telescope of Sayan observatory (Mondy) starting on March, 27 (UT) 13:48:49. We do not detect any source within enhanced Swift-XRT position (Goad et al., GCN 19237). In particular we do not detect the source reported in GCN 19236 and it could confirm the source (Zach Golkhou et al., GCN 19236) is an afterglow of the GRB 160327A. Preliminary photometry of the combined image is following
```
Date        UT start   t-T0    Filter  Exp.    UpperLimit (3 sigma)
                       (mid, days)      (s)

2016-03-27  13:48:49  0.20675  R       25*120  23.0
```
Photometry is based on nearby SDSS-DR9 stars, Lupton transformations into R.
GCN Circular #19242
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 151027A (Racusin et al., GCN 19235) starting at 09:17:37 UT, 90 s after the burst under fair condition. Observations were performed with an automatic sequence in the clear (roughly R), V, and I filters, and the exposure time was 20 s per image.
The afterglow reported by Zach et al. (GCN 19236) was not detected in any of our single images, however, it is detected in the co-added images in both clear and I band, except V band. We report the follow detection magnitude or upper limit:
```
Filter   co-add      Mid-time  Detection_Mag    Upper_limit

clear    20s x 10     549s      19.8 +/- 0.3    -
clear    20s x 10    1495s      20.2 +/- 0.4    -
clear    20s x 10    2162s            -         20.0
I        20s x 10     615s      18.1 +/- 0.2    -
I        20s x 10    1541s      18.8 +/- 0.4    -
I        20s x 10    2195s            -         18.7
V        20s x 15     781s            -         18.9
```
GCN Circular #19243
V. Zach Golkhou (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), and Vicki Toy (UMD) report:
We observed the field of GRB 160327A (Racusin, et al., GCN 19235) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2016/03 28.14 to 2016/03 28.39 UTC (17.98 to 24.15 hours after the BAT trigger), obtaining a total of 4.21 hours exposure in the r and i bands and 1.76 hours exposure in the Z, Y, J, and H bands.
For a source within the Swift-XRT error circle (Goad, et al., GCN 19237), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections:
```
  r	23.84 +/- 0.22
  i	23.29 +/- 0.14
  Z	22.57 +/- 0.20
  Y	22.83 +/- 0.35
  J	22.43 +/- 0.29
  H	21.75 +/- 0.23
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Compared to our previous night of observations (Golkhou et al., GCN 19236), the source flux has decayed substantially in all bands. The source r - i color changes from 2.1 +/- 0.1 to 0.6 +/- 0.3 between our first and the second night observations. The strong color change suggests the possibility of contamination by the GRB host galaxy at late-time.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #19245
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), N.R. Tanvir (U. Leicester),=20 Z. Cano (U. Iceland), L. Izzo (U. Roma1), J.P.U. Fynbo (DARK/NBI),=20 R. Sanchez-Ramirez (IAA-CSIC), C.C. Thoene (IAA-CSIC), P. Pesev=20 (GRANTECAN, IAC, ULL) report:
We observed the field of GRB 160327A (Racusin, et al., GCN 19235) with=20 OSIRIS mounted on the 10.4 m GTC telescope, located at Roque de los=20 Muchachos Observatory (La Palma, Spain) starting at 00:26 UT on 28th=20 March 2016 (15.17 hr after the burst).
In the acquisition image, we identify the afterglow proposed by Golkhou=20 et al. (GCN 19236) and later also observed by Zheng & Filippenko (GCN=20 19242). At the time of our observation, the object was at a magnitude=20 of i(AB) =3D 23.89 +/-0.12 (as compared to nearby SDSS stars), with=20 coordinates of (J2000.0, +/-0.5"):
```
R.A.: 09:46:48.56
Dec.: +54:00:46.3
```
We also note the presence of two other sources within 2.5=E2=80=9D of the= GRB=20 afterglow: The first one is located at 09:46:48.35, +54:00:47.8 and has a= =20 magnitude of i(AB) =3D 23.76+/-0.11, and the second one is at 09:46:48.55= ,=20 +54:00:44.2 with a magnitude of i(AB) =3D 24.24+/-0.15. We suspect that=20 these sources may be contributing to the magnitudes given by Golkhou=20 et al. (GCN 19243), especially in the bluer bands.
Spectroscopy of the GRB afterglow and the first of the two other objects=20 was obtained by exposing 3x1200 s with grism R1000R, which covers=20 between 5100 and 10100 Angstrom. We detect a trace of the GRB=20 afterglow above 7300 AA, below which the emission drops abruptly. The=20 other object shows a continuum over the complete spectral range,=20 suggesting that this object is unrelated to the GRB. The afterglow=20 spectrum is indicative of a Lyman-alpha drop at a redshift between 4.90=20 and 5.01, with a most probable value at z =3D 4.99, although even lower=20 redshifts could not be discarded for unusually large Hydrogen column=20 densities. Due to the low S/N of the spectrum we are not able to confirm=20 any other absorption lines at this time.
GCN Circular #19246
I.A. Smith (Rice U.), N.R. Tanvir (U. of Leicester), and Y. Urata (NCU) report:
We observed the location of GRB 160327A (Racusin et al., GCN Circ. 19235) using the SCUBA-2 sub-millimeter continuum camera on the James Clerk Maxwell Telescope. The observation started at 10:24 UT on 2016-03-27, corresponding to 68 minutes after the burst trigger. Exposures totaling 1.0 hours were made in good weather conditions. No source was detected, with the RMS background noise being 2.0 mJy/beam at 850 microns and 26.0 mJy/beam at 450 microns.
We thank Callie Matulonis and Iain Coulson for the prompt support of these observations that were taken under project M16AP005.
GCN Circular #19247
J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis, of Los Alamos National Laboratory report:
The RAPTOR network of robotic optical telescops made observations of Swift trigger 680655 (Racusin, et al., GCN 19235). Our Raptor-S telescope began imaging at 09:16:27.58 UT, 19.9 s after the Swift trigger time. We do not detect the optical counterpart reported by RATIR (Golkhou, et al., GCN 19236). We derive the following 3-sigma limits for our unfiltered observations based on comparison to the USNO-B1.0 catalog R-band.
```
t-mid(s)   exp(s)    mag_limit
-------------------------------
32.5       5         17.4
67.8       40        18.6
131.8      10        18.0
180.4      100       19.2
249.9      200       19.6
```
GCN Circular #19250
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
We observed the field of GRB 160327A (Racusin, et al., GCN 19235) for a third epoch with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2016/04 1.22 to 2016/04 1.41 UTC (115.97 to 120.62 hours after the BAT trigger), obtaining a total of 3.18 hours exposure in the r and i bands and 1.34 hours exposure in the Z, Y, J, and H bands.
We are able to detect two of the three sources identified by the GTC (de Ugarte Postigo, et al., GCN 19245). The afterglow (GTC source #1 and Golkhou, et al., GCN 19236) is detected in our night 2 observations on 28 March (Golkhou, et al., GCN 19243) but not on 1 April. The GTC source #2 is detected on 28 March and 1 April and is the dominant source in terms of brightness. We do not detect GTC source #3 on either night.
In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections and upper limits (3-sigma):
Afterglow (GTC Source #1):
```
 28 March                 1 April
r > 24.37               r > 24.41
i =3D 24.20 +/- 0.31      i > 24.38
Z =3D 22.98 +/- 0.28      Z > 23.15
Y > 22.85               Y > 22.91
J > 22.67               J > 22.61
H > 22.21               H > 22.23
```
GTC Source #2:
```
 28 March                 1 April
r =3D 23.84 +/- 0.22      r > 24.42
i =3D 23.33 +/- 0.14      i =3D 23.57 +/- 0.17
Z =3D 22.57 +/- 0.20      Z =3D 22.71 +/- 0.25
Y =3D 22.83 +/- 0.35      Y > 22.73
J =3D 22.43 +/- 0.29      J > 22.60
H =3D 21.75 +/- 0.24      H > 22.24
```
GTC Source #3:
```
 28 March                 1 April
r > 24.37               r > 24.41
i > 24.34               i > 24.39
Z > 23.19               Z > 23.11
Y > 22.86               Y > 22.76
J > 22.66               J > 22.6
H > 22.21               H > 22.25
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
In addition to our first night observations (Golkhou, et al., GCN 19236), which show the afterglow peaking and then fading, our observations on 28 March and 1 April confirm the fading of the afterglow. The above photometric analysis, based on PSF fitting, may still suffer from modest contamination between sources. More detailed analyses are under way.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #19453
K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), 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 160327A (Racusin et al., GCN 19235) 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 Mar 27.75, Mar 28.94, Mar 30.94, Apr 04.79, and Apr 06.83 (UT) do not reveal any radio source at the XRT location (Goad et al., GCN 19237), with 3sigma upper limits of 84 uJy, 69 uJy, 96 uJy, 102 uJy, and 93 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/.

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Jochen Greiner, last update: 24-May-2016 [Disclaimer]