Gamma-ray Burst 150910A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:17:45 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     655097,   Seg_Num: 0
GRB_RA:            5.675d {+00h 22m 42s} (J2000),
                   5.882d {+00h 23m 32s} (current),
                   5.018d {+00h 20m 04s} (1950)
GRB_DEC:         +33.499d {+33d 29' 55"} (J2000),
                 +33.586d {+33d 35' 08"} (current),
                 +33.222d {+33d 13' 17"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=912 [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:        17275 TJD;   253 DOY;   15/09/10
GRB_TIME:        32688.88 SOD {09:04:48.88} UT
GRB_PHI:         121.04 [deg]
GRB_THETA:        37.51 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.08 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -2  +0  +0 +74  +0 
SUN_POSTN:       168.37d {+11h 13m 29s}   +4.99d {+04d 59' 33"}
SUN_DIST:        138.01 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.96d {+09h 07m 50s}  +12.54d {+12d 32' 27"}
MOON_DIST:       114.47 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.08,-28.99 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       19.58, 28.27 [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 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 = 260.59,18.01 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:18:21 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     655097,   Seg_Num: 0
GRB_RA:            5.6669d {+00h 22m 40.05s} (J2000),
                   5.8738d {+00h 23m 29.70s} (current),
                   5.0093d {+00h 20m 02.24s} (1950)
GRB_DEC:         +33.4717d {+33d 28' 18.1"} (J2000),
                 +33.5586d {+33d 33' 30.9"} (current),
                 +33.1945d {+33d 11' 40.2"} (1950)
GRB_ERROR:       5.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       2.23e-09 [erg/cm2/sec]
GRB_SIGNIF:      8.36 [sigma]
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32834.18 SOD {09:07:14.18} UT,   145.3 [sec] since BAT Trigger Time
TAM[0-3]:        327.68 237.20 261.64 243.79
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 33"}
SUN_DIST:        138.04 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.96d {+09h 07m 51s}  +12.54d {+12d 32' 23"}
MOON_DIST:       114.49 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.07,-29.02 [deg] galactic lon,lat of the burst
ECL_COORDS:       19.56, 28.25 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.67 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:19:03 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     655097,   Seg_Num: 0
GRB_RA:            5.675d {+00h 22m 42s} (J2000),
                   5.882d {+00h 23m 32s} (current),
                   5.018d {+00h 20m 04s} (1950)
GRB_DEC:         +33.499d {+33d 29' 55"} (J2000),
                 +33.586d {+33d 35' 08"} (current),
                 +33.222d {+33d 13' 17"} (1950)
GRB_DATE:        17275 TJD;   253 DOY;   15/09/10
GRB_TIME:        32688.88 SOD {09:04:48.88} UT
TRIGGER_INDEX:   20000
GRB_PHI:         121.04 [deg]
GRB_THETA:        37.51 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    8.08 [sigma]
LC_URL:          sw00655097000msb.lc
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 32"}
SUN_DIST:        138.01 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.97d {+09h 07m 52s}  +12.54d {+12d 32' 18"}
MOON_DIST:       114.48 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.08,-28.99 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       19.58, 28.27 [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 an image 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 = 260.59,18.01 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:18:37 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     655097,   Seg_Num: 0
GRB_RA:            5.6669d {+00h 22m 40.0s} (J2000),
                   5.8738d {+00h 23m 29.7s} (current),
                   5.0093d {+00h 20m 02.2s} (1950)
GRB_DEC:         +33.4717d {+33d 28' 18.1"} (J2000),
                 +33.5586d {+33d 33' 30.9"} (current),
                 +33.1945d {+33d 11' 40.2"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       70 [cnts]
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32834.18 SOD {09:07:14.18} UT,   145.3 [sec] since BAT Trigger Time
CENTROID_X:      374.33,  raw= 374  [pixels]
CENTROID_Y:      289.31,  raw= 289  [pixels]
ROLL:            26.38 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -19.99
GRB_POS_XRT_Z:   162.74
IMAGE_URL:       sw00655097000msxps_rw.img
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 33"}
SUN_DIST:        138.04 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.96d {+09h 07m 52s}  +12.54d {+12d 32' 21"}
MOON_DIST:       114.50 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.07,-29.02 [deg] galactic lon,lat of the burst
ECL_COORDS:       19.56, 28.25 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:19:20 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.685d {+00h 22m 44s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
POINT_ROLL:      26.383d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32842.64 SOD {09:07:22.64} UT,   153.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.646
N_STARS:         32
X_OFFSET:        344 [pixels]
Y_OFFSET:        616 [pixels]
X_MAX:           1303 [pixels]
Y_MAX:           1575 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00655097000msufc0153.fits
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 32"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.97d {+09h 07m 53s}  +12.54d {+12d 32' 16"}
MOON_DIST:       114.46 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:18:31 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     655097,   Seg_Num: 0
GRB_RA:            5.6669d {+00h 22m 40.0s} (J2000),
                   5.8738d {+00h 23m 29.7s} (current),
                   5.0093d {+00h 20m 02.2s} (1950)
GRB_DEC:         +33.4717d {+33d 28' 18.1"} (J2000),
                 +33.5586d {+33d 33' 30.9"} (current),
                 +33.1945d {+33d 11' 40.2"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       70 [cnts]
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32834.18 SOD {09:07:14.18} UT,   145.3 [sec] since BAT Trigger Time
CENTROID_X:      374.33,  raw= 374  [pixels]
CENTROID_Y:      289.31,  raw= 289  [pixels]
ROLL:            26.38 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -19.99
GRB_POS_XRT_Z:   162.74
IMAGE_URL:       sw00655097000msxps_rw.img
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 33"}
SUN_DIST:        138.04 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.96d {+09h 07m 51s}  +12.54d {+12d 32' 22"}
MOON_DIST:       114.50 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.07,-29.02 [deg] galactic lon,lat of the burst
ECL_COORDS:       19.56, 28.25 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:19:49 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.685d {+00h 22m 44s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
POINT_ROLL:      26.383d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32842.64 SOD {09:07:22.64} UT,   153.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.646
N_STARS:         32
X_OFFSET:        344 [pixels]
Y_OFFSET:        616 [pixels]
X_MAX:           1303 [pixels]
Y_MAX:           1575 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw00655097000msufc0153.fits
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 32"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.97d {+09h 07m 54s}  +12.54d {+12d 32' 13"}
MOON_DIST:       114.47 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:20:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.685d {+00h 22m 44s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
ROLL:            26.383d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32842.64 SOD {09:07:22.64} UT,   153.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     463568857
X_OFFSET:        517 [pixels]
Y_OFFSET:        1061 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       677
Y_GRB_POS:       1221
BINNING_INDEX:   1
IM_URL:          sw00655097000msuni0169.fits
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 31"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.98d {+09h 07m 56s}  +12.54d {+12d 32' 07"}
MOON_DIST:       114.47 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:20:30 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.685d {+00h 22m 44s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
ROLL:            26.383d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32842.64 SOD {09:07:22.64} UT,   153.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     463568857
X_OFFSET:        517 [pixels]
Y_OFFSET:        1061 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       677
Y_GRB_POS:       1221
BINNING_INDEX:   1
IM_URL:          sw00655097000msuni0169.fits
SUN_POSTN:       168.37d {+11h 13m 30s}   +4.99d {+04d 59' 31"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      136.98d {+09h 07m 55s}  +12.54d {+12d 32' 08"}
MOON_DIST:       114.47 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:22:40 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     655097,   Seg_Num: 0
GRB_RA:            5.6672d {+00h 22m 40.12s} (J2000),
                   5.8741d {+00h 23m 29.77s} (current),
                   5.0096d {+00h 20m 02.31s} (1950)
GRB_DEC:         +33.4727d {+33d 28' 21.7"} (J2000),
                 +33.5596d {+33d 33' 34.5"} (current),
                 +33.1955d {+33d 11' 43.8"} (1950)
GRB_ERROR:       0.7 [arcsec radius, statistical only]
GRB_MAG:         20.27 +/- 0.17 [mag]
FILTER:          10, White
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  32840.00 SOD {09:07:20.00} UT,   151.1 [sec] since BAT Trigger Time
SUN_POSTN:       168.38d {+11h 13m 30s}   +4.99d {+04d 59' 29"}
SUN_DIST:        138.04 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.00d {+09h 08m 00s}  +12.53d {+12d 31' 53"}
MOON_DIST:       114.52 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.07,-29.02 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       19.56, 28.25 [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 3.6 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:23:42 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 54"} (J2000)
POINT_ROLL:      26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33000.88 SOD {09:10:00.88} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.501
N_STARS:         28
X_OFFSET:        197 [pixels]
Y_OFFSET:        741 [pixels]
X_MAX:           1156 [pixels]
Y_MAX:           1700 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00655097000msufc0312.fits
SUN_POSTN:       168.38d {+11h 13m 30s}   +4.99d {+04d 59' 28"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.01d {+09h 08m 02s}  +12.53d {+12d 31' 46"}
MOON_DIST:       114.49 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:24:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 54"} (J2000)
POINT_ROLL:      26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33000.88 SOD {09:10:00.88} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.501
N_STARS:         28
X_OFFSET:        197 [pixels]
Y_OFFSET:        741 [pixels]
X_MAX:           1156 [pixels]
Y_MAX:           1700 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw00655097000msufc0312.fits
SUN_POSTN:       168.38d {+11h 13m 30s}   +4.99d {+04d 59' 28"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.01d {+09h 08m 03s}  +12.53d {+12d 31' 44"}
MOON_DIST:       114.50 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:25:00 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 54"} (J2000)
ROLL:            26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33000.88 SOD {09:10:00.88} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     463569016
X_OFFSET:        517 [pixels]
Y_OFFSET:        1061 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       677
Y_GRB_POS:       1221
BINNING_INDEX:   1
IM_URL:          sw00655097000msuni0328.fits
SUN_POSTN:       168.38d {+11h 13m 31s}   +4.99d {+04d 59' 27"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.02d {+09h 08m 04s}  +12.53d {+12d 31' 37"}
MOON_DIST:       114.50 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:24:51 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 54"} (J2000)
ROLL:            26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33000.88 SOD {09:10:00.88} UT,   312.0 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     463569016
X_OFFSET:        517 [pixels]
Y_OFFSET:        1061 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       677
Y_GRB_POS:       1221
BINNING_INDEX:   1
IM_URL:          sw00655097000msuni0328.fits
SUN_POSTN:       168.38d {+11h 13m 31s}   +4.99d {+04d 59' 27"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.02d {+09h 08m 04s}  +12.53d {+12d 31' 38"}
MOON_DIST:       114.50 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:26:46 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
POINT_ROLL:      26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33555.31 SOD {09:19:15.31} UT,   866.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.502
N_STARS:         82
X_OFFSET:        0 [pixels]
Y_OFFSET:        501 [pixels]
X_MAX:           1439 [pixels]
Y_MAX:           1940 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00655097000msufc0866.fits
SUN_POSTN:       168.38d {+11h 13m 31s}   +4.99d {+04d 59' 25"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.03d {+09h 08m 08s}  +12.52d {+12d 31' 25"}
MOON_DIST:       114.51 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 10 Sep 15 09:26:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
POINT_ROLL:      26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33555.31 SOD {09:19:15.31} UT,   866.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.502
N_STARS:         82
X_OFFSET:        0 [pixels]
Y_OFFSET:        501 [pixels]
X_MAX:           1439 [pixels]
Y_MAX:           1940 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw00655097000msufc0866.fits
SUN_POSTN:       168.38d {+11h 13m 31s}   +4.99d {+04d 59' 25"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.03d {+09h 08m 08s}  +12.52d {+12d 31' 23"}
MOON_DIST:       114.52 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:28:09 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
ROLL:            26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33555.31 SOD {09:19:15.31} UT,   866.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     463569570
X_OFFSET:        559 [pixels]
Y_OFFSET:        1060 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       719
Y_GRB_POS:       1220
BINNING_INDEX:   1
IM_URL:          sw00655097000msuni0882.fits
SUN_POSTN:       168.38d {+11h 13m 31s}   +4.99d {+04d 59' 24"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.04d {+09h 08m 11s}  +12.52d {+12d 31' 15"}
MOON_DIST:       114.52 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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:     Thu 10 Sep 15 09:28:22 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     655097,   Seg_Num: 0
POINT_RA:          5.687d {+00h 22m 45s} (J2000)
POINT_DEC:       +33.515d {+33d 30' 53"} (J2000)
ROLL:            26.386d
IMG_START_DATE:  17275 TJD;   253 DOY;   15/09/10
IMG_START_TIME:  33555.31 SOD {09:19:15.31} UT,   866.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     463569570
X_OFFSET:        559 [pixels]
Y_OFFSET:        1060 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       719
Y_GRB_POS:       1220
BINNING_INDEX:   1
IM_URL:          sw00655097000msuni0882.fits
SUN_POSTN:       168.38d {+11h 13m 31s}   +4.99d {+04d 59' 23"}
SUN_DIST:        138.00 [deg]   Sun_angle= 10.8 [hr] (West of Sun)
MOON_POSTN:      137.05d {+09h 08m 11s}  +12.52d {+12d 31' 14"}
MOON_DIST:       114.53 [deg]
MOON_ILLUM:      8 [%]
GAL_COORDS:      116.10,-28.98 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       19.60, 28.28 [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 #18264
C. Pagani (U Leicester), A. P. Beardmore (U Leicester), A. A. Breeveld (UCL-MSSL), K. L. Page (U Leicester), P. Romano (INAF-IASFPA) and T. N. Ukwatta (LANL) report on behalf of the Swift Team:
At 09:04:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150910A (trigger=655097). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 5.675, +33.499 which is
```
   RA(J2000) = 00h 22m 42s
   Dec(J2000) = +33d 29' 55"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, the real-time light curve does not show anything significant.
The XRT began observing the field at 09:07:14.1 UT, 145.3 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 5.6669, 33.4717 which is equivalent to:
```
   RA(J2000)  = +00h 22m 40.06s
   Dec(J2000) = +33d 28' 18.1"
```
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This location is 101 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.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 153 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	00:22:40.14 =	5.66723
  DEC(J2000) = +33:28:21.9  =  33.47275
```
with a 90%-confidence error radius of about 0.71 arc sec. This position is 3.9 arc sec. from the center of the XRT error circle. The estimated magnitude is 20.27 with a 1-sigma error of about 0.18. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05.
Burst Advocate for this burst is C. Pagani (cp232 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)
GCN Circular #18265
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 150910A (Pagani et al., GCN 18264) starting at 09:34:20 UT, ~30 minutes after the burst. 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 UVOT afterglow reported by Pagani et al. (GCN 18264) was clearly detected in all filters. The brightness is about R~16.2 mag at ~30 minutes after the burst, and is decreasing. Follow-up observations are encouraged.
GCN Circular #18266
S. Dichiara, C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana), C. Mundell (U. Bath) on behalf of a larger collaboration report:
The 2-m LCOGT Faulkes Telescope North in Hawaii began observing Swift GRB 150910A (Pagani et al. GCN 18264) on September 10, 09:33:19 UT (28 minutes after the burst trigger) with SDSS r and i filters. We clearly detect the optical afterglow (Pagani et al. GCN 18264; Zheng et al. GCN 18265) with the following magnitudes:
```
Mid Time      Exposure       Filter       Magnitude
(min)           (s)
-------------------------------------------------------
29.0             60          r'           16.60 +- 0.02
35.6             60          i'           16.42 +- 0.02
-------------------------------------------------------
```
Calibration is done against SDSS magnitudes of nearby stars.
GCN Circular #18267
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 150910A (Pagani et al., GCNC 18264) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2015-09-10 10:20:44 UT (~1.3 h after the burst). We detected the previously reported afterglow (Pagani et al., GCNC 18264; Zheng and Filippenko, GCNC 18265; Dichiara et al., GCNC 18266) in all the three bands.
Photometric results of the OT are listed below. We used SDSS-DR7 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'  g'_err  Rc  Rc_err  Ic  Ic_err
-----------------------------------------------------------------------
0.05630    10:25:52     540.0     17.6 0.2    18.4 0.2    17.0 0.1
------------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18268
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), C. Pagani (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlinks, we report further analysis of BAT GRB 150910A (trigger #655097) (Pagani, et al., GCN Circ. 18264). The BAT ground-calculated position is RA, Dec = 5.677, 33.466 deg, which is
```
   RA(J2000)  =  00h 22m 42.5s 
   Dec(J2000) = +33d 27' 56.8" 
```
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 14%.
The mask-weighted light curve shows the burst definitely starting at ~T-150 sec (and posibly before T-240 when we start having data), peaking at ~T+83 sec, and ending at ~T+450 sec. T90 (15-350 keV) is 112.2 +- 38.3 sec (estimated error including systematics).
The time-averaged spectrum from T-5.00 to T+149.75 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.42 +- 0.12. The fluence in the 15-150 keV band is 4.8 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+82.89 sec in the 15-150 keV band is 1.1 +- 0.4 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/655097/BA/
GCN Circular #18269
D. Xu (NAOC/CAS), Y. Qin (Geneva Observatory), Y.-D. Hu (IAA-CSIC), Y.-H. Han (NAOC/CAS, HUST), X. Zhang, A. Esamdin, L. Ma (XAO) report:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) using the 1m telescope located at Nanshan, Xinjiang, China. We obtained 3x600s R-band frames with some floating clouds in the sky.
The afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is detected in each of the frames. Preliminary results are as follows
```
Mid Time  Exposure  Mag   MagErr
(hr)            (s)
4.91         600          19.40    0.20
5.14         600          19.55    0.20
5.31         600          19.30    0.20
```
and calibrated with the nearby SDSS field.

GCN Circular #18270
L. M. McCauley (PSU) and C. Pagani (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150910A 154 s after the BAT trigger (Pagani et al., GCN Circ. 18264). A source consistent with the XRT position (Pagani et al. GCN Circ. 18264) is detected in the initial UVOT exposures.
The preliminary UVOT position is:

    RA  (J2000) =  00:22:40.11 =   5.66713 (deg.)
    Dec (J2000) = +33:28:21.9  =  33.47274 (deg.)

with an estimated uncertainty of 0.58 arc sec. (radius, 90% confidence).
Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) show a very rapid and steep rise in the luminosity of the afterglow over the first 1 ks of observation. Further investigation is strongly encouraged. Preliminary detections for the early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white                 153            303         147         19.90
white                 156            303         144         19.93
white                 592            612          19         17.09
white                 765            785          19         16.67
white                 866           1016         147         16.30
v                     135            145           9        >17.23
v                     642            662          19         16.64
v                     815            835          19         16.91
v                    1046           1066          19         16.11
b                     568            588          19         17.56
b                     741            761          19         16.87
u                     312            561         245         18.03
u                     312            561         245         18.02
u                     716            736          19         16.14
uvw1                  692            712          19         16.76
uvw2                 1022           1041          19        >17.97

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998).

GCN Circular #18271
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 1428 s of XRT Photon Counting mode data and 5 UVOT images for GRB 150910A, 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 = 5.66723, +33.47278 which is equivalent to:
```
RA (J2000): 00h 22m 40.14s
Dec (J2000): +33d 28' 22.0"
```
with an uncertainty of 1.4 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 #18272
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M. McCauley (PSU) and C. Pagani report on behalf of the Swift-XRT team:
We have analysed 8.0 ks of XRT data for GRB 150910A (Pagani et al. GCN Circ. 18264), from 136 s to 35.1 ks after the BAT trigger. The data comprise 938 s in Windowed Timing (WT) mode (the first 7 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 Evans et al. (GCN Circ. 18271).
The late-time light curve (from T0+6.4 ks) can be modelled with a series of power-law decays. The initial decay index is alpha=0.67 (+0.23, -0.21). At T+10.9 ks the decay steepens to an alpha of 3.17 (+0.86, -0.30) before breaking again at T+20.3 ks to a final decay with index alpha=1.3 (+/-0.4).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.56 (+/-0.04). The best-fitting absorption column is 1.30 (+0.16, -0.15) x 10^21 cm^-2, in excess of the Galactic value of 5.4 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.77 (+0.09, -0.08) and a best-fitting absorption column of 7.1 (+2.3, -1.7) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     7.1 (+2.3, -1.7) x 10^20 cm^-2
Galactic foreground: 5.4 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.77 (+0.09, -0.08)
```
If the light curve continues to decay with a power-law decay index of 1.3, the count rate at T+24 hours will be 0.033 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-12 (1.4 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00655097.
This circular is an official product of the Swift-XRT team.
GCN Circular #18273
WeiKang Zheng, Alexei V. Filippenko and Heechan Yuk (UC Berkeley), Yinan Zhu (NAOC) and Daniel A. Perley (Dark Cosmology Center) report on behalf of the KAIT GRB team:
We observed the optical afterglow of GRB 150910A (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) with the Kast spectrograph on the 3m Shane telescope at Lick Observatory, started at 10:08 UT (about 1.1 hours after the burst), covering the 3500 - 10000 A wavelength range. A 1200-second and a 2400-second exposures were acquired.
The spectrum shows blue continuum flux across the entire spectral range. We detect absorption lines from Mg II (2796,2803) and Fe II (2344,2374,2383) at a common redshift of z=1.359, as well as additional lines further to the blue. We suggest this as the likely redshift of the GRB.
GCN Circular #18274
Antonio de Ugarte Postigo (IAA-CSIC, DARK/NBI), Christina Thoene (IAA-CSIC), Gianluca Lombardi (IAC, ULL, GRANTECAN), and Alberto Perez (GRANTECAN) report on behalf of a larger collaboration:
We have observed the afterglow of GRB 150910A (Pagani et al., GCN 18264) using the 10.4 m GTC telescope equipped with OSIRIS. Our observation began at 23:11 UT (14.1 hr after the burst) and consisted of 3x900s exposures using the R1000B grism. The spectrum covers the wavelength range between 3700 and 7800 AA.
The acquisition image shows the afterglow at a magnitude of r=20.65+/-0.07 as compared to SDSS stars.
The first spectrum shows a continuum throughout the full spectral range, with several absorption features that correspond to AlII, AlIII, FeII, MgII and MgI at a common redshift of 1.360, which we interpret as the reshift of the GRB.
GCN Circular #18275
A.S.Moskvitin (SAO RAS), V.P.Goranskij (SAI, Moscow State University), report on behalf of larger GRB follow-up team:
We observed the field of the GRB 150910A (Pagani et al., GCN #18264) with the Zeiss-1000, 1-meter telescope of SAO RAS (Russia), equipped with the broadband filters UBVRcIc and EEV 42-40 CCD. The observations started since 10.85 hours after the trigger.
We obtained sets of 6 x 300-sec. frames in Rc band three times per September, 10/11 night. The OT (reported by Pagani et al., GCN #18264; Zheng & Filippenko, GCN #18265; Dichiara et al., GCN #18266; Kuroda et al., GCN #18267; Xu et al., GCN #18269; McCauley & Pagani, GCN #18270; Zheng et al., GCN #18273; de Ugarte Postigo et al., GCN #18274) is clearly visible even in single frames. The results of observations are as following.
```
#   (T_mid-T0),h   exp.,s     R_mag            time, UT
1.  11.035         6 x 300    20.20 +/- 0.05   19:56:03--20:17:48
2.  13.448         6 x 300    20.57 +/- 0.05   22:15:17--22:48:09
3.  15.739         6 x 300    20.78 +/- 0.05   00:32:30--01:05:46
```
Photometry is based on nearby SDSS stars (their magnitudes were converted with the Lupon 2005 equations).
GCN Circular #18276
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 150910A (Pagani et al., GCNC 18264) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 2015-09-10 12:21:44 UT (~3.3 h after the burst). We detected the previously reported afterglow (Pagani et al., GCNC 18264; Zheng and Filippenko, GCNC 18265; Dichiara et al., GCNC 18266; Kuroda et al., GCNC 18267) in all the three bands.
Photometric results of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'  g'_err  Rc  Rc_err  Ic  Ic_err
-----------------------------------------------------------------------
0.14010    12:26:33     540.0     19.1 0.1    18.8 0.1    18.4 0.1
-----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18277
S. Schmidl (TLS Tautenburg), F. Knust, and J. Greiner (both MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 150910A (SWIFT trigger 655097; Pagani et al, GCN 18264) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla Observatory (Chile).
Observations started on September 11, 2015, at 05:08 UT, 20.1 hrs after the GRB trigger. They were performed at an average seeing of 2.8" and at an average airmass of 2.2.
We clearly detect the optical afterglow reported by Pagani et al. (GCN 18264), Zheng & Filippenko (GCN 18265), Dichiara et al. (GCN 18266), Kuroda et al. (GCN 18267), Xu et al. (GCN 18269), de Ugarte Postigo et al. (GCN 18274) and Moskvitin et al (GCN 18275).
Based on total exposures of 7.7 minutes in g'r'i'z'and 4.0 minutes in JHK, at a midtime of 20.8 hrs after the burst, we measure the following preliminary magnitudes (AB magnitude system):
```
g' = 21.5 +/- 0.2 mag,
r' = 21.2 +/- 0.2 mag,
i' = 21.0 +/- 0.2 mag,
z' = 20.8 +/- 0.2 mag,
J  > 19.8 mag,
H  > 19.3 mag, and
K  > 18.1 mag.
```
Given magnitudes and upper limits are calibrated against SDSS as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.05 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #18278
Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Hideyuki Izumiura (OAO/NAOJ), Michitoshi Yoshida (Hiroshima-U), Kouji Ohta(Kyoto-U), and Nobuyuki Kawai(Tokyo Tech.) report on behalf of the MITSuME collaboration:
We observed the field of GRB150910A (Pagani et al., GCNC 18264) in Ks-band with a wide-field NIR camera at Okayama Astrophysical Observatory (Japan). The camera has an effective aperture of 0.91m.
Observations started from 10:03 UT on 10th September, 59 min after the BAT trigger, to 11:14 UT. The total exposure of 26 min was successfully obtained.
In our co-add image, we found a single point source at
```
  R.A.(J2000) = 00:22:39.84
  DEC (J2000) = +33:28:20.5
```
with an uncertainty of of about 2 arcsec.
We estimate the magnitude Ks = 14.85 +/- 0.13 (Vega). The calibration was made against 2MASS field stars.
```
T0+[min]    MID-UT     T-EXP[min]    Ks
------------------------------------------------------------
  +94       10:38        26          14.85 +/- 0.13 (Vega)
------------------------------------------------------------
T0+ : Elapsed time after the burst [min]
T-EXP: Total Exposure time [min]
```
GCN Circular #18279
Z. Cano (U. Iceland), D. Malesani (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. Xu (NAOC/CAS), J. Saario (NOT, U. Turku) and P. Jakobsson (U. Iceland) report on behalf of a larger collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN Circ. 18264) with the 2.5-m Nordic Optical Telescope (NOT) equipped with MOSCA in two epochs on the morning of 11-Sept-2015, at 01:10 and 04:45 UT, respectively. In SDSS filters r (epoch 1) and ugrz (epoch 2) we clearly detect the optical afterglow (e.g. Zheng & Filippenko, GCN Circ. 18265).
A summary of our photometry is as follows:
```
-------------------------------------------------------
filter (SDSS)        t-t0 (hr)            mag +- merr
-------------------------------------------------------
   r                  16.27              20.85 +- 0.18
   r                  20.18              21.24 +- 0.21
   u                  20.05              21.82 +- 0.24
   g                  20.24              21.49 +- 0.22
   z                  19.84              20.78 +- 0.24
```
These magnitudes are calibrated to SDSS and are not corrected for foreground extinction. We note that these magnitudes are in good agreement with those obtained by GROND (Schmidl et al., GCN Circ. 18277) at a contemporaneous post-explosion epoch. Compared with other datasets, e.g. Xu et al. (GCN Circ. 18269), our second epoch of r-band observations implies a power-law like decay in time, e.g. f(t)=3Dt^-alpha, with a decay slope of alpha=1. =E2=80=8B1.
GCN Circular #18281
E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory on Sep. 10 (UT) 18:02:59 -- 20:37:38. We obtained several images in R and B filters. In both filters the afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is clearly visible. Within 2.5 hours of observations we do not detect significant fading of the afterglow. The photometry of combined images are following
```
Date       UT start    t-T0     Filter  Exp.     OT       Err
                        (mid, days)      (s)

2015-09-10 18:08:20    0.42807  R       11*300   20.18 +/- 0.05
2015-09-10 18:02:59    0.42436  B       12*300   20.85 +/- 0.08
```
The photometry is based on nearby SDSS stars
```
SDSS_id            R(Lupton)
J002232.47+332751.3    16.29
J002236.24+332854.2    15.92
J002241.61+332836.1    16.23
J002248.33+332723.4    16.76
J002231.90+333004.8    16.93
J002225.39+332809.6    16.12
J002246.76+332716.9    17.63
```
Our photometry in R-filter is in agreement with in subsequent observations (Moskvitin & Goranskij, GCN 18275).
GCN Circular #18284
A. S. Moskvitin (SAO RAS), report on behalf of larger GRB follow-up team:
The field of the GRB 150910A (Pagani et al., GCN #18264) was observed with the Zeiss-1000 telescope of SAO RAS (Russia) in Rc band on September, 11.791 (T_mid-T0 = 1.413 days), 17:55:54--20:01:44 UT.
20 x 300 seconds frames were obtained. The OT is still clearly visible in the stacked image. The brightness of the object R = 22.2 +/- 0.10 (based on the same SDSS stars as in previous circular GCN #18275).
GCN Circular #18285
K. Alexander (Harvard), T. Laskar (NRAO / UC Berkeley), and E. Berger (Harvard) report on behalf of a larger collaboration:
We observed GRB 150910A (Pagani et al; GCN 18264) at multiple frequencies with the Karl G. Jansky Very Large Array (VLA) beginning 2015 September 11.10 UT (0.72 days after the burst). At a mean frequency of 9.8 GHz, we detect a radio source with a preliminary flux density of ~ 0.1 mJy at
```
RA = 00:22:40.120 +/- 0.021
Dec = +33:28:21.750 +/- 0.036
```
consistent with the UVOT optical position (McCauley et al; GCN 18270) and the enhanced Swift/XRT position (Evans et al.; GCN 18271). Follow-up observations are planned.
GCN Circular #18287
Yu. Krugly (IA KhNU), E. Mazaeva (IKI), V. Shevchenko (IA KhNU), T. Gromakina (IA KhNU), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) with 0.7m telescope of Institute of Astronomy, Kharkiv National University starting on Sep. 10 (UT) 21:41:15. We obtained several images in R B filter. The afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is clearly visible in a combined image. The photometry of the combined image is following
```
Date       UT start    t-T0     Filter  Exp.     OT       Err
                        (mid, days)      (s)

2015-09-10 21:41:15    0.52235  R       11*180   20.25 +/-0.14
```
The photometry is based on SDSS stars used in GCN 18281 (Mazaeva et al.)
GCN Circular #18288
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 150910A (Pagani et al., GCNC 18264) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 2015-09-11 12:29:42 UT (~1.14 days after the burst). We detected the previously reported afterglow (Pagani et al., GCNC 18264; Zheng and Filippenko, GCNC 18265; Dichiara et al., GCNC 18266; Kuroda et al., GCNC 18267) in g' and Rc bands.
Photometric results and three sigma upper limit of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'  g'_err  Rc  Rc_err  Ic  Ic_err
-----------------------------------------------------------------------
1.21526    14:14:46    4800.0     21.8 0.2    21.2 0.2    >20.8
-----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18289
E. Mazaeva (IKI), R. Inasaridze (AAO), V. Zhuzhunadze (AAO), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) with with AS-32 (0.7m) telescope of Abastumani Observatory starting on Sep. 10 (UT) 18:53:54. We obtained several unfiltered images. The afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is clearly visible in a combined image. The photometry of the combined image is following
```
Date       UT start    t-T0     Filter  Exp.     OT       Err
                        (mid, days)      (s)

2015-09-10 18:53:54    0.45834  none    50*120   20.16 +/- 0.06
```
The photometry is based on SDSS stars used in GCN 18281 (Mazaeva et al.)
GCN Circular #18295
D. A. Perley (DARK) and S. B. Cenko (NASA/GSFC) report:
We observed the location of GRB 150910A (Pagani et al., GCN 18264) using the robotic Palomar 60-inch telescope on two epochs during the night of 2015-09-11 UT, and an additional epoch during the night of 2015-09-12 UT. During each epoch we acquired 3x180s of imaging in each of the g', r', and i' filters.
The optical afterglow (Pagani et al.; Zheng and Filippenko, GCN 18265) is detected in each observation. Preliminary photometry relative to SDSS yields:
```
t_start(d)  filt   mag      emag
    0.973    i  =  21.24 +/- 0.12
    0.980    g  =  21.54 +/- 0.06
    0.989    r  =  21.35 +/- 0.08
    1.067    i  =  21.28 +/- 0.07
    1.074    g  =  21.85 +/- 0.06
    1.081    r  =  21.50 +/- 0.06
    2.060    i  =  22.21 +/- 0.17
    2.067    g  =  22.66 +/- 0.14
    2.074    r  =  23.03 +/- 0.26
```
GCN Circular #18301
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 150910A (Pagani et al., GCNC 18264) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory.
The observation started on 2015-09-12 13:59:26 UT (~2.2 days after the burst). We detected the previously reported afterglow (Pagani et al., GCNC 18264; Zheng and Filippenko, GCNC 18265; Dichiara et al., GCNC 18266; Kuroda et al., GCNC 18267) in Rc band.
Photometric results and three sigma upper limit of the OT are listed below. We used GSC2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc  Rc_err  Ic
-----------------------------------------------------------------------
2.22658    14:31:04    3240.0    >22.4   22.3 0.4   >20.73
-----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #18302
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (UCB), J. Xavier Proch= aska (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), Ca= rlos 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 150910A (Pagani et al., GCN 18264) 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 2015/09 13.15 to 2015/09 13.26 UTC (66= .44 to 69.21 hours after the BAT trigger), obtaining a total of 0.99 hour= s exposure in the r, i, and z bands.
The optical afterglow (Pagani et al.; Zheng and Filippenko, GCN 18265) is= well detected. In comparison with the SDSS DR9 catalog, we obtain:
```
   r 22.44 +/- 0.13
   i 22.31 +/- 0.11
   z > 20.29 (3-sigma)
```
These magnitudes are in the AB system and are not corrected for Galactic = extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #18306
M. Andreev (Terskol Branch of INASAN), E. Mazaeva (IKI), A. Sergeev (Terskol Branch of INASAN), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) with Zeiss-600 telescope of Mt. Terskol observatory in R-filter starting on Sep. 10 (UT) 20:45:05. We obtained several unfiltered images. The afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is clearly detected in a combined image. The photometry of the combined image is following
Date UT start t-T0 Filter Exp. OT Err (mid, days) (s)
2015-09-10 20:45:05 0.51974 R 46*120 20.46 +/- 0.07
The photometry is based on SDSS stars used in GCN 18281 (Mazaeva et al.)
GCN Circular #18312
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (UCB), J. Xavier Proch= aska (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), Ca= rlos 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 150910A (Pagani et al., GCN 18264) 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 2015/09 14.17 to 2015/09 14.46 UTC (90= .88 to 98.01 hours after the BAT trigger), obtaining a total of 1.71 hour= s exposure in the r, i, and z bands.
The optical afterglow (Pagani et al.; Zheng and Filippenko, GCN 18265) is= well detected. In comparison with the SDSS DR9 catalog, we obtain:
```
   r = 22.23 +/- 0.09
   i = 22.44 +/- 0.10
   z > 19.89 (3-sigma)
```
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 o= f observations (Butler et al., GCN 18302), the source flux is consistent = with remaining constant at the ~1-sigma level. Also, the source appears = to be extended in our images, suggesting that the flux may be dominated b= y the GRB host galaxy.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #18314
E. Sonbas (Adiyaman Univ.), O. Basturk (Ankara Univ.), T. Guver (Istanbul Univ.), E. Gogus (Sabanci Univ.), S. Eryilmaz, O. Erece, H. Kirbiyik (TUG) report on behalf of a larger collaboration
We observed the field of Swift GRB 150910A (Pagani et al., GCN#18264) with the 1.0 meter T100 telescope (Bakirlitepe, TUBITAK National Observatory, Turkey), starting September, 10, 20:08:16 UT (~ 11 hours after the trigger). Observations were carried out in the R filter. The afterglow is detected in the R band images with an exposure time of 300 s.
Using USNO-B1 star USNO-B1 1234-0008068 (R.A.=5.65, Dec=+33.45) in the field, the magnitudes of the OT were estimated as follows;
t-t0 (hr) exp.(s) filt mag err (+/-)
10.97 300 R 20.09 0.23
11.06 300 R 20.18 0.25
Analysis of further observations with the same filter is ongoing.
We thank to TUBITAK National Observatory for a partial support in using T100 telescope with project number 10CT100-95 and technical support.
GCN Circular #18319
A. Volnova (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin (Fesenkov Astrophysical Institute), E. Mazaeva (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory on Sep. 11 and Sep. 12. We obtained several images in R filter. The afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is clearly visible in a combined image on Sep. 11 and on Sep. 12 we obtained upper limit. The photometry of the combined images are following
```
Date       UT start    t-T0     Filter  Exp.     OT       Err
                        (mid, days)      (s)

2015-09-11 18:39:41    1.38753  R       16*300   21.87    0.10
2015-09-12 19:03:44    2.39553  R       21*300   >22.3   (3 sigma)
```
The photometry is based on SDSS stars used in GCN 18281 (Mazaeva et al.)
GCN Circular #18320
A. Volnova (IKI), A. Sergeev (Terskol Branch of INASAN), M. Andreev (Terskol Branch of INASAN), E. Mazaeva (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) with Zeiss-2000 telescope of Mt. Terskol observatory in R-filter starting on Sep. 11 (UT) 00:40:58. The afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is clearly detected in a each image. The photometry of a combined image is following
```
Date UT start       t-T0    Filter Exp.   OT     Err
                     (mid, days)    (s)

2015-09-11 00:40:58 0.67083 R      13*120 20.90  0.07
```
The photometry is based on SDSS stars used in GCN 18281 (Mazaeva et al.)
GCN Circular #18327
E. Mazaeva (IKI), R. Inasaridze (AAO), O. Kvaratskhelia(AAO), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 150910A (Pagani et al., GCN 18264) with AS-32 (0.7m) telescope of Abastumani Observatory starting on Sep. 11 (UT) 20:32:45. We obtained several unfiltered images. The afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is clearly visible in a combined image. The photometry of the combined image is following
```
Date       UT start    t-T0     Filter  Exp.     OT       Err
                        (mid, days)      (s)

2015-09-11 20:32:45    1.46327  none    49*120   21.55 +/- 0.08
```
The photometry is based on SDSS stars used in GCN 18281 (Mazaeva et al.), R magnitude deduced from Lupton's transformations.
GCN Circular #18556
V. Rumyantsev (CrAO), E. Mazaeva (IKI), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 150910A (Pagani et al., GCN 18264) with ZTSh telescope of CrAO observatory on Sep. 11 and Sep. 12. We took several images in R,B-filters of 120 s exposure under good weather conditions on Sep. 11 and non-optimal weather conditions (mean seeing of 4") on Sep. 12.
The photometry of the afterglow (Pagani et al., GCN 18264; Zheng & Filippenko, GCN 18265) is following
```
Date       UT start,  t-t0     Filter   Exp.    OT    OT_err UL(3sigma)
                       (mid, days)        (s)

2015-09-11 17:56:37   1.3762   R        10*120  21.69 0.12   22.9
2015-09-11 18:18:31   1.4022   B        20*120  22.48 0.15   23.5
2015-09-11 18:39:47   1.4244   R        10*120  21.82 0.10   23.2
2015-09-11 19:22:17   1.4436   B        16*120  22.09 0.10   23.5
2015-09-12 18:04:32   2.3801   R        10*120  n/d   n/a    22.3
```
The photometry is based on SDSS stars used in GCN 18281 (Mazaeva et al.)

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Jochen Greiner, last update: 03-Nov-2015 [Disclaimer]