Gamma-ray Burst 150925A

(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 25 Sep 15 04:10:47 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     656604,   Seg_Num: 0
GRB_RA:          227.520d {+15h 10m 05s} (J2000),
                 227.744d {+15h 10m 59s} (current),
                 226.807d {+15h 07m 14s} (1950)
GRB_DEC:         -19.628d {-19d 37' 41"} (J2000),
                 -19.687d {-19d 41' 13"} (current),
                 -19.439d {-19d 26' 19"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=2128 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        17290 TJD;   268 DOY;   15/09/25
GRB_TIME:        14968.81 SOD {04:09:28.81} UT
GRB_PHI:         -37.88 [deg]
GRB_THETA:        35.49 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    12.64 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  +2  +0  +0 -65  +0 
SUN_POSTN:       181.64d {+12h 06m 34s}   -0.71d {-00d 42' 37"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.72d {+21h 26m 52s}  -11.51d {-11d 30' 46"}
MOON_DIST:        89.81 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      230.47, -1.83 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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 = 136.55,-6.93 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:12:19 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     656604,   Seg_Num: 0
GRB_RA:          227.5358d {+15h 10m 08.59s} (J2000),
                 227.7605d {+15h 11m 02.51s} (current),
                 226.8228d {+15h 07m 17.47s} (1950)
GRB_DEC:         -19.6342d {-19d 38' 03.1"} (J2000),
                 -19.6932d {-19d 41' 35.5"} (current),
                 -19.4450d {-19d 26' 41.8"} (1950)
GRB_ERROR:       4.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       3.82e-09 [erg/cm2/sec]
GRB_SIGNIF:      10.95 [sigma]
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15108.91 SOD {04:11:48.91} UT,   140.1 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.23 261.52 243.67
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       181.64d {+12h 06m 34s}   -0.71d {-00d 42' 38"}
SUN_DIST:         48.95 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.73d {+21h 26m 55s}  -11.51d {-11d 30' 32"}
MOON_DIST:        89.81 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      342.34, 32.42 [deg] galactic lon,lat of the burst
ECL_COORDS:      230.49, -1.83 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.97 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:12:32 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     656604,   Seg_Num: 0
GRB_RA:          227.5358d {+15h 10m 08.5s} (J2000),
                 227.7605d {+15h 11m 02.5s} (current),
                 226.8228d {+15h 07m 17.4s} (1950)
GRB_DEC:         -19.6342d {-19d 38' 03.1"} (J2000),
                 -19.6932d {-19d 41' 35.5"} (current),
                 -19.4450d {-19d 26' 41.8"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       120 [cnts]
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15108.91 SOD {04:11:48.91} UT,   140.1 [sec] since BAT Trigger Time
CENTROID_X:      319.13,  raw= 319  [pixels]
CENTROID_Y:      302.72,  raw= 303  [pixels]
ROLL:            287.21 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   11.61
GRB_POS_XRT_Z:   32.60
IMAGE_URL:       sw00656604000msxps_rw.img
SUN_POSTN:       181.64d {+12h 06m 34s}   -0.71d {-00d 42' 39"}
SUN_DIST:         48.95 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.73d {+21h 26m 56s}  -11.51d {-11d 30' 30"}
MOON_DIST:        89.81 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      342.34, 32.42 [deg] galactic lon,lat of the burst
ECL_COORDS:      230.49, -1.83 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:12:40 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     656604,   Seg_Num: 0
GRB_RA:          227.5358d {+15h 10m 08.5s} (J2000),
                 227.7605d {+15h 11m 02.5s} (current),
                 226.8228d {+15h 07m 17.4s} (1950)
GRB_DEC:         -19.6342d {-19d 38' 03.1"} (J2000),
                 -19.6932d {-19d 41' 35.5"} (current),
                 -19.4450d {-19d 26' 41.8"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       120 [cnts]
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15108.91 SOD {04:11:48.91} UT,   140.1 [sec] since BAT Trigger Time
CENTROID_X:      319.13,  raw= 319  [pixels]
CENTROID_Y:      302.72,  raw= 303  [pixels]
ROLL:            287.21 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   11.61
GRB_POS_XRT_Z:   32.60
IMAGE_URL:       sw00656604000msxps_rw.img
SUN_POSTN:       181.64d {+12h 06m 34s}   -0.71d {-00d 42' 39"}
SUN_DIST:         48.95 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.73d {+21h 26m 56s}  -11.51d {-11d 30' 29"}
MOON_DIST:        89.81 [deg]
MOON_ILLUM:      87 [%]
GAL_COORDS:      342.34, 32.42 [deg] galactic lon,lat of the burst
ECL_COORDS:      230.49, -1.83 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:20:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.527d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.628d {-19d 37' 41"} (J2000)
POINT_ROLL:      287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15117.51 SOD {04:11:57.51} UT,   148.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.610
N_STARS:         60
X_OFFSET:        528 [pixels]
Y_OFFSET:        528 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1487 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    16
SL_URL:          sw00656604000msufc0148.fits
SUN_POSTN:       181.65d {+12h 06m 35s}   -0.71d {-00d 42' 47"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.82d {+21h 27m 16s}  -11.49d {-11d 29' 17"}
MOON_DIST:        89.90 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.82 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:21:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.527d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.628d {-19d 37' 41"} (J2000)
POINT_ROLL:      287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15117.51 SOD {04:11:57.51} UT,   148.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        8.610
N_STARS:         60
X_OFFSET:        528 [pixels]
Y_OFFSET:        528 [pixels]
X_MAX:           1487 [pixels]
Y_MAX:           1487 [pixels]
DET_THRESH:      26
PHOTO_THRESH:    16
SL_URL:          sw00656604000msufc0148.fits
SUN_POSTN:       181.65d {+12h 06m 35s}   -0.71d {-00d 42' 47"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.82d {+21h 27m 17s}  -11.49d {-11d 29' 13"}
MOON_DIST:        89.91 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.82 [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 25 Sep 15 04:23:27 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.527d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.628d {-19d 37' 41"} (J2000)
ROLL:            287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15117.51 SOD {04:11:57.51} UT,   148.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     464847132
X_OFFSET:        741 [pixels]
Y_OFFSET:        891 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       901
Y_GRB_POS:       1051
BINNING_INDEX:   1
IM_URL:          sw00656604000msuni0164.fits
SUN_POSTN:       181.65d {+12h 06m 35s}   -0.71d {-00d 42' 49"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.84d {+21h 27m 22s}  -11.48d {-11d 28' 53"}
MOON_DIST:        89.93 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.82 [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:     Fri 25 Sep 15 04:23:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.527d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.628d {-19d 37' 41"} (J2000)
ROLL:            287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15117.51 SOD {04:11:57.51} UT,   148.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     464847132
X_OFFSET:        741 [pixels]
Y_OFFSET:        891 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       901
Y_GRB_POS:       1051
BINNING_INDEX:   1
IM_URL:          sw00656604000msuni0164.fits
SUN_POSTN:       181.65d {+12h 06m 35s}   -0.71d {-00d 42' 49"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.84d {+21h 27m 22s}  -11.48d {-11d 28' 52"}
MOON_DIST:        89.93 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.82 [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:     Fri 25 Sep 15 04:25:31 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
POINT_ROLL:      287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15275.65 SOD {04:14:35.65} UT,   306.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.768
N_STARS:         41
X_OFFSET:        421 [pixels]
Y_OFFSET:        571 [pixels]
X_MAX:           1380 [pixels]
Y_MAX:           1530 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00656604000msufc0306.fits
SUN_POSTN:       181.65d {+12h 06m 36s}   -0.71d {-00d 42' 51"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.86d {+21h 27m 27s}  -11.48d {-11d 28' 34"}
MOON_DIST:        89.95 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:26:00 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     656604,   Seg_Num: 0
GRB_RA:          227.5339d {+15h 10m 08.13s} (J2000),
                 227.7586d {+15h 11m 02.05s} (current),
                 226.8209d {+15h 07m 17.02s} (1950)
GRB_DEC:         -19.6325d {-19d 37' 57.0"} (J2000),
                 -19.6915d {-19d 41' 29.4"} (current),
                 -19.4433d {-19d 26' 35.7"} (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:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15273.00 SOD {04:14:33.00} UT,   304.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       181.65d {+12h 06m 36s}   -0.71d {-00d 42' 52"}
SUN_DIST:         48.94 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.87d {+21h 27m 28s}  -11.48d {-11d 28' 30"}
MOON_DIST:        89.95 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.34, 32.42 [deg] galactic lon,lat of the burst
ECL_COORDS:      230.49, -1.83 [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 25 Sep 15 04:25:56 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
POINT_ROLL:      287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15275.65 SOD {04:14:35.65} UT,   306.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        2.768
N_STARS:         41
X_OFFSET:        421 [pixels]
Y_OFFSET:        571 [pixels]
X_MAX:           1380 [pixels]
Y_MAX:           1530 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00656604000msufc0306.fits
SUN_POSTN:       181.65d {+12h 06m 36s}   -0.71d {-00d 42' 52"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.87d {+21h 27m 28s}  -11.48d {-11d 28' 31"}
MOON_DIST:        89.95 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [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 25 Sep 15 04:27:07 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
ROLL:            287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15275.65 SOD {04:14:35.65} UT,   306.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     464847290
X_OFFSET:        741 [pixels]
Y_OFFSET:        891 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       901
Y_GRB_POS:       1051
BINNING_INDEX:   1
IM_URL:          sw00656604000msuni0322.fits
SUN_POSTN:       181.65d {+12h 06m 36s}   -0.71d {-00d 42' 53"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.88d {+21h 27m 31s}  -11.47d {-11d 28' 20"}
MOON_DIST:        89.96 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [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:     Fri 25 Sep 15 04:27:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
ROLL:            287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15275.65 SOD {04:14:35.65} UT,   306.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     464847290
X_OFFSET:        741 [pixels]
Y_OFFSET:        891 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       901
Y_GRB_POS:       1051
BINNING_INDEX:   1
IM_URL:          sw00656604000msuni0322.fits
SUN_POSTN:       181.65d {+12h 06m 36s}   -0.71d {-00d 42' 53"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.88d {+21h 27m 31s}  -11.47d {-11d 28' 19"}
MOON_DIST:        89.97 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [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 #18365
J. L. Racusin (NASA/GSFC), A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
At 04:09:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150925A (trigger=656604). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 227.520, -19.628 which is
```
   RA(J2000) = 15h 10m 05s
   Dec(J2000) = -19d 37' 41"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Only partial BAT lightcurve data is currently available, and so no description of this image trigger can be given.
The XRT began observing the field at 04:11:48.9 UT, 140.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 227.5340, -19.6325 which is equivalent to:
```
   RA(J2000)  = 15h 10m 08.16s
   Dec(J2000) = -19d 37' 57.1"
```
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 50 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 in excess of the Galactic value (1.01 x 10^21 cm^-2, Willingale et al. 2013), with an excess column of 4.7 (+4.53/-2.33) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 3.82e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 148 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 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 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 0.10.
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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:32:13 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
POINT_ROLL:      287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15832.04 SOD {04:23:52.04} UT,   863.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.854
N_STARS:         190
X_OFFSET:        181 [pixels]
Y_OFFSET:        331 [pixels]
X_MAX:           1620 [pixels]
Y_MAX:           1770 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00656604000msufc0863.fits
SUN_POSTN:       181.65d {+12h 06m 37s}   -0.72d {-00d 42' 58"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.93d {+21h 27m 43s}  -11.46d {-11d 27' 34"}
MOON_DIST:        90.02 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:32:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
POINT_ROLL:      287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15832.04 SOD {04:23:52.04} UT,   863.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.854
N_STARS:         190
X_OFFSET:        181 [pixels]
Y_OFFSET:        331 [pixels]
X_MAX:           1620 [pixels]
Y_MAX:           1770 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw00656604000msufc0863.fits
SUN_POSTN:       181.65d {+12h 06m 37s}   -0.72d {-00d 42' 58"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.93d {+21h 27m 44s}  -11.46d {-11d 27' 31"}
MOON_DIST:        90.02 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 25 Sep 15 04:33:52 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
ROLL:            287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15832.04 SOD {04:23:52.04} UT,   863.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     464847847
X_OFFSET:        740 [pixels]
Y_OFFSET:        890 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       900
Y_GRB_POS:       1050
BINNING_INDEX:   1
IM_URL:          sw00656604000msuni0879.fits
SUN_POSTN:       181.65d {+12h 06m 37s}   -0.72d {-00d 43' 00"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.95d {+21h 27m 47s}  -11.46d {-11d 27' 19"}
MOON_DIST:        90.03 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [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 25 Sep 15 04:34:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     656604,   Seg_Num: 0
POINT_RA:        227.529d {+15h 10m 07s} (J2000)
POINT_DEC:       -19.630d {-19d 37' 48"} (J2000)
ROLL:            287.213d
IMG_START_DATE:  17290 TJD;   268 DOY;   15/09/25
IMG_START_TIME:  15832.04 SOD {04:23:52.04} UT,   863.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     464847847
X_OFFSET:        740 [pixels]
Y_OFFSET:        890 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       900
Y_GRB_POS:       1050
BINNING_INDEX:   1
IM_URL:          sw00656604000msuni0879.fits
SUN_POSTN:       181.65d {+12h 06m 37s}   -0.72d {-00d 43' 00"}
SUN_DIST:         48.93 [deg]   Sun_angle= -3.1 [hr] (East of Sun)
MOON_POSTN:      321.95d {+21h 27m 48s}  -11.46d {-11d 27' 17"}
MOON_DIST:        90.04 [deg]
MOON_ILLUM:      88 [%]
GAL_COORDS:      342.33, 32.43 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      230.48, -1.83 [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 #18366
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1379 s of XRT Photon Counting mode data and 1 UVOT images for GRB 150925A, 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 = 227.53421, -19.63298 which is equivalent to:
```
RA (J2000): 15h 10m 8.21s
Dec (J2000): -19d 37' 58.7"
```
with an uncertainty of 1.5 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 #18367
A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), P. D'Avanzo (INAF-OAB) and J.L. Racusin report on behalf of the Swift-XRT team:
We have analysed 9.0 ks of XRT data for GRB 150925A (Racusin et al. GCN Circ. 18365), from 129 s to 22.8 ks after the BAT trigger. The data comprise 175 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 18366).
The light curve can be modelled with an initial power-law decay with an index of alpha=3.30 (+/-0.09), followed by a break at T+877 s to an alpha of 1.20 (+0.19, -0.22).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.62 (+/-0.09). The best-fitting absorption column is 2.7 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 1.0 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.89 (+0.25, -0.23) and a best-fitting absorption column of 3.4 (+1.2, -1.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.1 x 10^-11 (5.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.4 (+1.2, -1.0) x 10^21 cm^-2
Galactic foreground: 1.0 x 10^21 cm^-2
Excess significance: 3.8 sigma
Photon index:	     1.89 (+0.25, -0.23)
```
If the light curve continues to decay with a power-law decay index of 1.20, the count rate at T+24 hours will be 6.3 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.6 x 10^-14 (3.7 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00656604.
This circular is an official product of the Swift-XRT team.
GCN Circular #18368
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlinks, we report further analysis of BAT GRB 150925A (trigger #656604) (Racusin, et al., GCN Circ. 18365). The BAT ground-calculated position is RA, Dec = 227.538, -19.640 deg, which is
```
   RA(J2000)  =  15h 10m 09.0s 
   Dec(J2000) = -19d 38' 22.3" 
```
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 56%.
The mask-weighted light curve show several overlapping peaks starting at ~T-0, peaking at ~T+25 sec, and ending at ~T+180 sec. T90 (15-350 keV) is 121 +- 27 sec (estimated error including systematics).
The time-averaged spectrum from T+3.51 to T+149.61 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.19 +- 0.20. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+30.68 sec in the 15-150 keV band is 0.6 +- 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/656604/BA/
GCN Circular #18369
M. H. Siegel (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 150925A 149 s after the BAT trigger (Racusin et al., GCN Circ. 18365). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 18366) 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           149          298          147         >20.2
u_FC               307          557          246         >19.7
white              149        13178         1385         >21.2
v                  637         7068          510         >19.7
b                  563        18924         1676         >20.7
u                  307        18430         2310         >20.2
w1                 688        17516         1333         >20.8
m2                1589        22808          586         >21.1
w2                1019         6864          452         >19.8
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998).

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Jochen Greiner, last update: 26-Sep-2015 [Disclaimer]