Gamma-ray Burst 150727A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:16:28 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     650530,   Seg_Num: 0
GRB_RA:          203.990d {+13h 35m 58s} (J2000),
                 204.202d {+13h 36m 48s} (current),
                 203.313d {+13h 33m 15s} (1950)
GRB_DEC:         -18.355d {-18d 21' 16"} (J2000),
                 -18.434d {-18d 26' 01"} (current),
                 -18.100d {-18d 05' 58"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5134 [cnts]    Image_Peak=202 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       32136 [cnts]
BKG_TIME:        68505.08 SOD {19:01:45.08} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17230 TJD;   208 DOY;   15/07/27
GRB_TIME:        68522.43 SOD {19:02:02.43} UT
GRB_PHI:         -122.38 [deg]
GRB_THETA:        25.20 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     14.89 [sigma]
IMAGE_SIGNIF:    7.59 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -2  +0  +0  -9  +0 
SUN_POSTN:       126.78d {+08h 27m 08s}  +19.15d {+19d 08' 49"}
SUN_DIST:         84.75 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.01d {+17h 04m 01s}  -17.90d {-17d 54' 15"}
MOON_DIST:        49.05 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.50, 43.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      208.93, -7.78 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 12.07,-11.78 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(6.0<100sec) coincident with the FERMI_GBM event (trignum=459716520).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:17:06 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     650530,   Seg_Num: 0
GRB_RA:          203.9705d {+13h 35m 52.91s} (J2000),
                 204.1817d {+13h 36m 43.61s} (current),
                 203.2933d {+13h 33m 10.38s} (1950)
GRB_DEC:         -18.3259d {-18d 19' 33.2"} (J2000),
                 -18.4050d {-18d 24' 18.1"} (current),
                 -18.0708d {-18d 04' 15.0"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       8.93e-09 [erg/cm2/sec]
GRB_SIGNIF:      15.49 [sigma]
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68599.58 SOD {19:03:19.58} UT,   77.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.69 237.19 261.70 243.66
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       126.78d {+08h 27m 08s}  +19.15d {+19d 08' 48"}
SUN_DIST:         84.72 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.01d {+17h 04m 03s}  -17.90d {-17d 54' 16"}
MOON_DIST:        49.08 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.49, 43.29 [deg] galactic lon,lat of the burst
ECL_COORDS:      208.90, -7.76 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 2.06 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:17:14 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     650530,   Seg_Num: 0
GRB_RA:          203.9705d {+13h 35m 52.9s} (J2000),
                 204.1817d {+13h 36m 43.6s} (current),
                 203.2933d {+13h 33m 10.3s} (1950)
GRB_DEC:         -18.3259d {-18d 19' 33.2"} (J2000),
                 -18.4050d {-18d 24' 18.1"} (current),
                 -18.0708d {-18d 04' 15.0"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       240 [cnts]
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68599.58 SOD {19:03:19.58} UT,   77.2 [sec] since BAT Trigger Time
CENTROID_X:      221.89,  raw= 222  [pixels]
CENTROID_Y:      276.91,  raw= 277  [pixels]
ROLL:            292.25 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -49.22
GRB_POS_XRT_Z:   -196.61
IMAGE_URL:       sw00650530000msxps_rw.img
SUN_POSTN:       126.78d {+08h 27m 08s}  +19.15d {+19d 08' 48"}
SUN_DIST:         84.72 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.01d {+17h 04m 03s}  -17.90d {-17d 54' 17"}
MOON_DIST:        49.08 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.49, 43.29 [deg] galactic lon,lat of the burst
ECL_COORDS:      208.90, -7.76 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:17:28 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     650530,   Seg_Num: 0
GRB_RA:          203.9705d {+13h 35m 52.9s} (J2000),
                 204.1817d {+13h 36m 43.6s} (current),
                 203.2933d {+13h 33m 10.3s} (1950)
GRB_DEC:         -18.3259d {-18d 19' 33.2"} (J2000),
                 -18.4050d {-18d 24' 18.1"} (current),
                 -18.0708d {-18d 04' 15.0"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       240 [cnts]
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68599.58 SOD {19:03:19.58} UT,   77.2 [sec] since BAT Trigger Time
CENTROID_X:      221.89,  raw= 222  [pixels]
CENTROID_Y:      276.91,  raw= 277  [pixels]
ROLL:            292.25 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -49.22
GRB_POS_XRT_Z:   -196.61
IMAGE_URL:       sw00650530000msxps_rw.img
SUN_POSTN:       126.78d {+08h 27m 08s}  +19.15d {+19d 08' 48"}
SUN_DIST:         84.72 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.01d {+17h 04m 04s}  -17.91d {-17d 54' 17"}
MOON_DIST:        49.08 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.49, 43.29 [deg] galactic lon,lat of the burst
ECL_COORDS:      208.90, -7.76 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:18:06 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     650530,   Seg_Num: 0
GRB_RA:          203.990d {+13h 35m 58s} (J2000),
                 204.202d {+13h 36m 48s} (current),
                 203.313d {+13h 33m 15s} (1950)
GRB_DEC:         -18.355d {-18d 21' 16"} (J2000),
                 -18.434d {-18d 26' 01"} (current),
                 -18.100d {-18d 05' 58"} (1950)
GRB_DATE:        17230 TJD;   208 DOY;   15/07/27
GRB_TIME:        68522.43 SOD {19:02:02.43} UT
TRIGGER_INDEX:   146
GRB_PHI:         -122.38 [deg]
GRB_THETA:        25.20 [deg]
DELTA_TIME:      25.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     14.89 [sigma]
IMAGE_SIGNIF:    7.59 [sigma]
LC_URL:          sw00650530000msb.lc
SUN_POSTN:       126.78d {+08h 27m 08s}  +19.15d {+19d 08' 48"}
SUN_DIST:         84.75 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.02d {+17h 04m 05s}  -17.91d {-17d 54' 19"}
MOON_DIST:        49.06 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.50, 43.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      208.93, -7.78 [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 = 12.07,-11.78 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:18:19 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.018d {+13h 36m 04s} (J2000)
POINT_DEC:       -18.360d {-18d 21' 34"} (J2000)
POINT_ROLL:      292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68608.43 SOD {19:03:28.43} UT,   86.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.513
N_STARS:         29
X_OFFSET:        632 [pixels]
Y_OFFSET:        416 [pixels]
X_MAX:           1591 [pixels]
Y_MAX:           1375 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00650530000msufc0086.fits
SUN_POSTN:       126.78d {+08h 27m 08s}  +19.15d {+19d 08' 48"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.02d {+17h 04m 06s}  -17.91d {-17d 54' 19"}
MOON_DIST:        49.04 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:18:48 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.018d {+13h 36m 04s} (J2000)
POINT_DEC:       -18.360d {-18d 21' 34"} (J2000)
POINT_ROLL:      292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68608.43 SOD {19:03:28.43} UT,   86.0 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.513
N_STARS:         29
X_OFFSET:        632 [pixels]
Y_OFFSET:        416 [pixels]
X_MAX:           1591 [pixels]
Y_MAX:           1375 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00650530000msufc0086.fits
SUN_POSTN:       126.78d {+08h 27m 08s}  +19.15d {+19d 08' 47"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.03d {+17h 04m 07s}  -17.91d {-17d 54' 21"}
MOON_DIST:        49.04 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [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 27 Jul 15 19:19:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.018d {+13h 36m 04s} (J2000)
POINT_DEC:       -18.360d {-18d 21' 34"} (J2000)
ROLL:            292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68608.43 SOD {19:03:28.43} UT,   86.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     459716623
X_OFFSET:        1194 [pixels]
Y_OFFSET:        756 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1354
Y_GRB_POS:       916
BINNING_INDEX:   1
IM_URL:          sw00650530000msuni0101.fits
SUN_POSTN:       126.79d {+08h 27m 08s}  +19.15d {+19d 08' 47"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.04d {+17h 04m 09s}  -17.91d {-17d 54' 23"}
MOON_DIST:        49.05 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [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:     Mon 27 Jul 15 19:19:55 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.018d {+13h 36m 04s} (J2000)
POINT_DEC:       -18.360d {-18d 21' 34"} (J2000)
ROLL:            292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68608.43 SOD {19:03:28.43} UT,   86.0 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     459716623
X_OFFSET:        1194 [pixels]
Y_OFFSET:        756 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1354
Y_GRB_POS:       916
BINNING_INDEX:   1
IM_URL:          sw00650530000msuni0101.fits
SUN_POSTN:       126.79d {+08h 27m 08s}  +19.15d {+19d 08' 47"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.04d {+17h 04m 09s}  -17.91d {-17d 54' 23"}
MOON_DIST:        49.05 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [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:     Mon 27 Jul 15 19:22:03 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     650530,   Seg_Num: 0
GRB_RA:          203.9688d {+13h 35m 52.51s} (J2000),
                 204.1800d {+13h 36m 43.20s} (current),
                 203.2916d {+13h 33m 09.98s} (1950)
GRB_DEC:         -18.3253d {-18d 19' 31.0"} (J2000),
                 -18.4044d {-18d 24' 15.9"} (current),
                 -18.0702d {-18d 04' 12.8"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         18.30 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68606.00 SOD {19:03:26.00} UT,   83.6 [sec] since BAT Trigger Time
SUN_POSTN:       126.79d {+08h 27m 09s}  +19.15d {+19d 08' 46"}
SUN_DIST:         84.72 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.06d {+17h 04m 14s}  -17.91d {-17d 54' 28"}
MOON_DIST:        49.12 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.49, 43.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      208.90, -7.76 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 6.1 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:22:49 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.020d {+13h 36m 05s} (J2000)
POINT_DEC:       -18.358d {-18d 21' 29"} (J2000)
POINT_ROLL:      292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68820.53 SOD {19:07:00.53} UT,   298.1 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.017
N_STARS:         18
X_OFFSET:        874 [pixels]
Y_OFFSET:        436 [pixels]
X_MAX:           1833 [pixels]
Y_MAX:           1395 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00650530000msufc0298.fits
SUN_POSTN:       126.79d {+08h 27m 09s}  +19.15d {+19d 08' 45"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.07d {+17h 04m 16s}  -17.91d {-17d 54' 30"}
MOON_DIST:        49.08 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 27 Jul 15 19:23:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.020d {+13h 36m 05s} (J2000)
POINT_DEC:       -18.358d {-18d 21' 29"} (J2000)
POINT_ROLL:      292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68820.53 SOD {19:07:00.53} UT,   298.1 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.017
N_STARS:         18
X_OFFSET:        874 [pixels]
Y_OFFSET:        436 [pixels]
X_MAX:           1833 [pixels]
Y_MAX:           1395 [pixels]
DET_THRESH:      9
PHOTO_THRESH:    4
SL_URL:          sw00650530000msufc0298.fits
SUN_POSTN:       126.79d {+08h 27m 09s}  +19.15d {+19d 08' 45"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.07d {+17h 04m 17s}  -17.91d {-17d 54' 31"}
MOON_DIST:        49.08 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [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 27 Jul 15 19:24:19 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.020d {+13h 36m 05s} (J2000)
POINT_DEC:       -18.358d {-18d 21' 29"} (J2000)
ROLL:            292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68820.53 SOD {19:07:00.53} UT,   298.1 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     459716835
X_OFFSET:        1194 [pixels]
Y_OFFSET:        756 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1354
Y_GRB_POS:       916
BINNING_INDEX:   1
IM_URL:          sw00650530000msuni0313.fits
SUN_POSTN:       126.79d {+08h 27m 09s}  +19.15d {+19d 08' 44"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.08d {+17h 04m 19s}  -17.91d {-17d 54' 34"}
MOON_DIST:        49.09 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [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:     Mon 27 Jul 15 19:24:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     650530,   Seg_Num: 0
POINT_RA:        204.020d {+13h 36m 05s} (J2000)
POINT_DEC:       -18.358d {-18d 21' 29"} (J2000)
ROLL:            292.247d
IMG_START_DATE:  17230 TJD;   208 DOY;   15/07/27
IMG_START_TIME:  68820.53 SOD {19:07:00.53} UT,   298.1 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     459716835
X_OFFSET:        1194 [pixels]
Y_OFFSET:        756 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1354
Y_GRB_POS:       916
BINNING_INDEX:   1
IM_URL:          sw00650530000msuni0313.fits
SUN_POSTN:       126.79d {+08h 27m 09s}  +19.15d {+19d 08' 44"}
SUN_DIST:         84.77 [deg]   Sun_angle= -5.2 [hr] (East of Sun)
MOON_POSTN:      256.08d {+17h 04m 20s}  -17.91d {-17d 54' 34"}
MOON_DIST:        49.09 [deg]
MOON_ILLUM:      84 [%]
GAL_COORDS:      317.54, 43.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      208.96, -7.78 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #18076
S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 19:02:02 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150727A (trigger=650530). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 203.990, -18.355, which is
```
   RA(J2000)  =  13h 35m 58s
   Dec(J2000) = -18d 21' 16"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a large FRED-like peak structure with a duration of about 60 sec. The peak count rate was ~2795 counts/sec (15-350 keV), at ~4 sec after the trigger.
The XRT began observing the field at 19:03:19.5 UT, 77.2 seconds after the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source located at RA, Dec 203.9705, -18.3259 which is equivalent to:
```
   RA(J2000)  = +13h 35m 52.92s
   Dec(J2000) = -18d 19' 33.2"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 124 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
The initial flux in the 2.5 s image was 8.93e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 86 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	13:35:52.52 = 203.96883
  DEC(J2000) = -18:19:31.4  = -18.32539
```
with a 90%-confidence error radius of about 0.62 arc sec. This position is 6.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.31 with a 1-sigma error of about 0.15. No correction has been made for extinction.
Burst Advocate for this burst is S. B. Cenko (brad.cenko 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 #18079
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1662 s of XRT Photon Counting mode data and 4 UVOT images for GRB 150727A, 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 = 203.96843, -18.32576 which is equivalent to:
```
RA (J2000): 13h 35m 52.42s
Dec (J2000): -18d 19' 32.7"
```
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 #18080
N. R. Tanvir (U. Leicester), D. Xu (NAOC/CAS), T. Zafar (ESO), S. Covino (INAF/OABr), S. Schulze (PUC, MAS) report for a larger collaboration:
We observed the afterglow of GRB 150727A (Cenko et al. GCN 18076) with VLT/X-shooter, beginning at 2015-07-28 00:01 UT, about 5 hr after the burst.
Preliminary analysis of the spectrum reveals emission lines of Halpha, Hbeta and [OIII] 4959/5007 at a redshift of z=0.313. There is only marginal evidence of the [OII] 3727 doublet, suggesting the emission lines are coming from a dust obscured region (consistent also with a high Ha:Hb ratio). The continuum is faint with no clear absorption lines, but can be traced in the blue as far as the instrumental cut-off at about 3100A. Despite the absence of detected absorption features, it is likely that the emission lines are from the host galaxy and therefore that this redshift is also that of the GRB.
GCN Circular #18081
G. Younes (GWU) reports on behalf of the Fermi GBM Team:
"At 19:01:56.35 UT on July 27 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150727A (trigger 459716520/150727793), which was also detected by Swift (Cenko et al. 2015, GCN 18076). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with the Swift/XRT location.
The angle of the burst direction to the Fermi LAT boresight is 46 degrees.
The GBM light curve shows a FRED-like (fast-rise exponential-decay) pulse with a duration (T90) of about 50s (50-300 keV). The time-averaged spectrum from T0-4s to T0+56s is well fit by a power law with an exponential high-energy cutoff. The power law index is -0.7 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 149 +/- 10 keV.
The event fluence (10-1000 keV) in this time interval is (7.9 +/- 0.3)E-06 ergs/cm^2. The 1.0-sec peak photon flux measured starting from T0+5.0s in the 10-1000 keV band is 2.1 +/- 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 #18082
K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester) and S.B. Cenko report on behalf of the Swift-XRT team:
We have analysed 8.0 ks of XRT data for GRB 150727A (Cenko et al. GCN Circ. 18076), from 68 s to 32.5 ks after the BAT trigger. The data comprise 523 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 18079).
The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=1.2 (+/-0.4). At T+93.8 s the decay steepens to an alpha of 2.72 (+0.11, -0.08). The light curve breaks again at T+195 s to a decay with alpha=1.42 (+0.07, -0.06), and again at T+3169 s s to alpha=8.0 (+0.0, -5.8), before a final break at T+4539 s s after which the decay index is 0.5 (+/-0.3).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.39 (+/-0.04). The best-fitting absorption column is 2.0 (+/-1.5) x 10^20 cm^-2, at a redshift of 0.313, in addition to the Galactic value of 9.8 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 2.7 x 10^-11 (3.9 x 10^-11) erg cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
```
Galactic foreground: 9.8 x 10^20 cm^-2
Intrinsic column:    2.0 (+/-1.5) x 10^20 cm^-2 at z=0.313
Photon index:	     2.39 (+/-0.04)
```
If the light curve continues to decay with a power-law decay index of 0.5, the count rate at T+24 hours will be 8.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x 10^-13 (3.4 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/00650530.
This circular is an official product of the Swift-XRT team.
GCN Circular #18083
S. Dichiara, C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of a large collaboration report:
Using a 1-m LCOGTN telescope in Cerro Tololo (Chile), we began observing GRB 150727A (Cenko et al. GCN 18076; Younes et al. GCN 18081) on July 28 01:23:01 UT (~6.3 hours after the burst trigger) with r' and i' filters.
We did not detect the UVOT counterpart (Cenko et al. 2015, GCN 18076) down to the following limit:
```
Mid time from  Total Exp   Filter    Magnitude
trigger (hr)   (s)
-------------------------------------------------
6.71           120x10        r'        > 18.9
6.76           120x9         i'        > 16.5
-------------------------------------------------
```
Values have been calibrated against nearby USNOB-1 stars (R2 and I).
GCN Circular #18084
A. A. Breeveld (UCL-MSSL) and S. B. Cenko (GSFC) report on behalf of the=20 Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150727A 86 s after the BAT trigger (Cenko et al., GCN Circ. 18076). A fading source consistent with the enhanced XRT position (Osborne et=20 al. GCN Circ. 18079) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
     RA  (J2000) =3D  13:35:52.52 =3D 203.96885 (deg.)
     Dec (J2000) =3D -18:19:31.3  =3D -18.32536 (deg.)
```
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).
Preliminary detections in the white, u and uvw2 filters and 3-sigma=20 upper limits using the UVOT photometric system (Breeveld et al. 2011,=20 AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               86          236          147         18.28 =C2=B1 0.06
white              578          598           20         18.75 =C2=B1 0.24
v                 4036         4236          197        >18.7
b                  554          574           19        >18.5
u                  298          548          246         18.75 =C2=B1 0.16
m2                4241         4379          136        >19.1
w2                3831         4031          197         19.53 =C2=B1 0.36
```
The magnitudes in the table are not corrected for the Galactic=20 extinction due to the reddening in the direction of the burst.
GCN Circular #18085
A. Martin-Carrillo (UCD), D. Murphy (UCD), L. Hanlon (UCD), M. Topinka (CTU), H. J. van Heerden (UFS), B. van Soelen (UFS) and P. J. Meintjes (UFS):
We observed the field of GRB 150727A (Cenko et al., GCN Circ. #18076) using the 40cm UCD Watcher telescope at Boyden Observatory in South Africa.
Observations started at 19:19:55 UT, 1073 seconds after the burst trigger. A series of 60 sec images were taken in the SDSS r' filter using an Andor CCD camera. No afterglow candidate is detected in any of the individual images at the UVOT location. A 3sigma upper limit for a combined 180 second exposure is given below.
```
Start             | End              | Exposure | Filter | Magnitude
-------------------------------------------------------------------------------------------------
19:19:55 UT | 19:25:20 UT | 3x60 sec |  r'       |  >17.59 (3sigma upper limit)
```
The upper limit was calculated using nearby stars from the APASS catalogue.
This message can be cited in publications.
GCN Circular #18086
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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 downlinks, we report further analysis of BAT GRB 150727A (trigger #650530) (Cenko, et al., GCN Circ. 18076). The BAT ground-calculated position is RA, Dec = 203.968, -18.320 deg, which is
```
   RA(J2000)  =  13h 35m 52.3s 
   Dec(J2000) = -18d 19' 11.4" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 68%.
The mask-weighted light curve shows a FRED-like peak starting at ~T-8 sec, peaking at ~T+5 sec, and ramping down to a flat level at ~T+80 sec. There is a second, small peak at ~T+90 sec. The low level emission continues (with a weak decline) out to T+870 sec when observations stop due to an observing constraint. T90 (15-350 keV) is 88 +- 133 sec (estimated error including systematics).
The time-averaged spectrum from T-8.70 to T+95.94 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.14 +- 0.07. The fluence in the 15-150 keV band is 3.7 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+9.21 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/650530/BA/
GCN Circular #18089
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), Willia= m=20 H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB)= ,=20 J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara=20 (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico=20 Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM),=20 Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels= (GSFC),=20 and Harvey Moseley (GSFC) report:
We observed the field of GRB 150727A (Cenko et al., GCN 18076) with the=20 Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the= =20 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional = on=20 Sierra San Pedro M=E1rtir from 2015/07 28.15 to 2015/07 28.21 UTC (8.65 t= o=20 9.95 hours after the BAT trigger), obtaining a total of 1.07 hours=20 exposure in the r, i, and z bands.
We detect a source at the edge of the Swift/XRT error circle (Osborne et=20 al., GCN 18079), at RA, Dec (J2000) =3D 13:35:52.52, -18:19:31.4 (=B10.5"= ). In=20 comparison with the USNO-B1 and 2MASS catalogs, we obtain the following=20 detections and upper limits (3-sigma):
```
   r	21.13 =B1 0.19
   i	21.40 =B1 0.13
   z	> 19.57
```
These magnitudes are in the AB system and are not corrected for Galactic=20 extinction in the direction of the GRB.
Our detections appear to be consistent with the non-detections at=20 shallower depths reported by Dichiara et al. (GCN 18083). Tanvir et al.=20 (GCN 18080) report a tentative spectroscopic redshift of 0.313.
Further observations are planned.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #18095
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), 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), and Harvey Moseley (GSFC) report:
We observed the field of GRB 150727A (Cenko et al., GCN 18076) 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 2015/07 29.15 to 2015/07 29.19 UTC (32.64 to 33.50 hours after the BAT trigger), obtaining a total of 0.70 hours exposure in the r, i, and z bands.
We no longer detect the source seen on the previous night (Watson et al., GCN 18089). In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma):
```
   r	> 22.27
   i	> 22.61
   z	> 19.11
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
The source has faded by at least 1 magnitude in both r and i. We therefore suggest that it it corresponds to the afterglow.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #18113
K. L. Murata (Nagoya U.), T. Kusune (Nagoya City U.), H. Onozato (Tohoku U.) and T. Nagayama (Kagoshima U.)
We observed the field of GRB 150727A (Cenko et al., GCN Circular #18076) with the near-infrared (J, H, Ks) simultaneous imaging polarimeter SIRPOL attached to 1.4 m telescope IRSF (InfraRed Survey Facility) in Sutherland observatory, South Africa.
The observations started on 2015-07-27 19:25:30 UT (~ 9 min. after the burst). We detected an uncatalogued source within 5 arcsec from the Swift/UVOT preliminary position reported in the GCN circular of Breeveld et al. (GCN Circular #18084). We have obtained the following preliminary magnitude (Vega magnitude system):
```
J   = 18.9 +- 0.2
H   = 18.1 +- 0.1
Ks  = 17.1 +- 0.2
```
Given magnitudes were calibrated against 2MASS point sources in this field.
This observation was carried out by IRSF and OISTER collaboration.

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Jochen Greiner, last update: 04-Aug-2015 [Disclaimer]