Gamma-ray Burst 131030A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 20:56:33 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     576238,   Seg_Num: 0
GRB_RA:          345.080d {+23h 00m 19s} (J2000),
                 345.259d {+23h 01m 02s} (current),
                 344.432d {+22h 57m 44s} (1950)
GRB_DEC:          -5.389d {-05d 23' 20"} (J2000),
                  -5.315d {-05d 18' 52"} (current),
                  -5.658d {-05d 39' 27"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       13173 [cnts]    Image_Peak=1487 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   147     E_range: 25-100 keV
BKG_INTEN:       36144 [cnts]
BKG_TIME:        75364.78 SOD {20:56:04.78} UT
BKG_DUR:         8 [sec]
GRB_DATE:        16595 TJD;   303 DOY;   13/10/30
GRB_TIME:        75378.80 SOD {20:56:18.80} UT
GRB_PHI:         132.52 [deg]
GRB_THETA:        32.58 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     126.43 [sigma]
IMAGE_SIGNIF:    21.38 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +7  +0  +0 +59  +0 
SUN_POSTN:       215.24d {+14h 20m 58s}  -14.04d {-14d 02' 37"}
SUN_DIST:        126.77 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.72d {+11h 22m 52s}   -0.18d {-00d 10' 34"}
MOON_DIST:       172.26 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.36,-55.77 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      344.18,  0.91 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 8.38,-1.55 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Wed 30 Oct 13 20:57:28 UT
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger 
TRIGGER_NUM:    6380,   Sub_Num: 0
GRB_INTEN:      9.32 [sigma]
GRB_TIME:       75371.32 SOD {20:56:11.32} UT
GRB_DATE:       16595 TJD;   303 DOY;   13/10/30
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=2.0000 and Time_Error=1.0000.
COMMENTS:       
COMMENTS:       NOTE: This SPIACS event is temporally(7.0<100sec) coincident with the SWIFT_BAT event (trignum=576238).
COMMENTS: 
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2013-10/2013-10-30T20-56-11.2541-07796-11152-0.lc

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 20:58:10 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     576238,   Seg_Num: 0
GRB_RA:          345.0657d {+23h 00m 15.76s} (J2000),
                 345.2447d {+23h 00m 58.73s} (current),
                 344.4181d {+22h 57m 40.34s} (1950)
GRB_DEC:          -5.3659d {-05d 21' 57.2"} (J2000),
                  -5.2915d {-05d 17' 29.3"} (current),
                  -5.6345d {-05d 38' 04.1"} (1950)
GRB_ERROR:       5.1 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       5.43e-08 [erg/cm2/sec]
GRB_SIGNIF:      8.94 [sigma]
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75457.16 SOD {20:57:37.16} UT,   78.4 [sec] since BAT Trigger Time
TAM[0-3]:        327.66 237.22 261.54 243.65
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       215.24d {+14h 20m 58s}  -14.04d {-14d 02' 39"}
SUN_DIST:        126.77 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.73d {+11h 22m 55s}   -0.18d {-00d 10' 51"}
MOON_DIST:       172.26 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.37,-55.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      344.18,  0.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.62 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 20:58:17 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     576238,   Seg_Num: 0
GRB_RA:          345.0657d {+23h 00m 15.7s} (J2000),
                 345.2447d {+23h 00m 58.7s} (current),
                 344.4181d {+22h 57m 40.3s} (1950)
GRB_DEC:          -5.3659d {-05d 21' 57.2"} (J2000),
                  -5.2915d {-05d 17' 29.3"} (current),
                  -5.6345d {-05d 38' 04.1"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       80 [cnts]
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75457.16 SOD {20:57:37.16} UT,   78.4 [sec] since BAT Trigger Time
CENTROID_X:      318.99,  raw= 319  [pixels]
CENTROID_Y:      267.78,  raw= 268  [pixels]
ROLL:            248.06 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -71.21
GRB_POS_XRT_Z:   36.04
IMAGE_URL:       sw00576238000msxps_rw.img
SUN_POSTN:       215.24d {+14h 20m 58s}  -14.04d {-14d 02' 39"}
SUN_DIST:        126.77 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.73d {+11h 22m 56s}   -0.18d {-00d 10' 52"}
MOON_DIST:       172.26 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.37,-55.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      344.18,  0.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 20:58:24 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     576238,   Seg_Num: 0
GRB_RA:          345.0657d {+23h 00m 15.7s} (J2000),
                 345.2447d {+23h 00m 58.7s} (current),
                 344.4181d {+22h 57m 40.3s} (1950)
GRB_DEC:          -5.3659d {-05d 21' 57.2"} (J2000),
                  -5.2915d {-05d 17' 29.3"} (current),
                  -5.6345d {-05d 38' 04.1"} (1950)
GRB_ERROR:       5.0 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       80 [cnts]
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75457.16 SOD {20:57:37.16} UT,   78.4 [sec] since BAT Trigger Time
CENTROID_X:      318.99,  raw= 319  [pixels]
CENTROID_Y:      267.78,  raw= 268  [pixels]
ROLL:            248.06 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   -71.21
GRB_POS_XRT_Z:   36.04
IMAGE_URL:       sw00576238000msxps_rw.img
SUN_POSTN:       215.24d {+14h 20m 58s}  -14.04d {-14d 02' 39"}
SUN_DIST:        126.77 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.73d {+11h 22m 56s}   -0.18d {-00d 10' 54"}
MOON_DIST:       172.25 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.37,-55.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      344.18,  0.93 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 21:00:40 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.066d {+23h 00m 16s} (J2000)
POINT_DEC:        -5.390d {-05d 23' 24"} (J2000)
POINT_ROLL:      248.053d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75468.41 SOD {20:57:48.41} UT,   89.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.624
N_STARS:         103
X_OFFSET:        481 [pixels]
Y_OFFSET:        715 [pixels]
X_MAX:           1440 [pixels]
Y_MAX:           1674 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00576238000msufc0089.fits
SUN_POSTN:       215.24d {+14h 20m 58s}  -14.04d {-14d 02' 41"}
SUN_DIST:        126.76 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.75d {+11h 23m 00s}   -0.19d {-00d 11' 18"}
MOON_DIST:       172.22 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 21:01:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.066d {+23h 00m 16s} (J2000)
POINT_DEC:        -5.390d {-05d 23' 24"} (J2000)
POINT_ROLL:      248.053d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75468.41 SOD {20:57:48.41} UT,   89.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.624
N_STARS:         103
X_OFFSET:        481 [pixels]
Y_OFFSET:        715 [pixels]
X_MAX:           1440 [pixels]
Y_MAX:           1674 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw00576238000msufc0089.fits
SUN_POSTN:       215.24d {+14h 20m 58s}  -14.05d {-14d 02' 41"}
SUN_DIST:        126.76 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.75d {+11h 23m 01s}   -0.19d {-00d 11' 22"}
MOON_DIST:       172.22 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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:     Wed 30 Oct 13 21:02:17 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.066d {+23h 00m 16s} (J2000)
POINT_DEC:        -5.390d {-05d 23' 24"} (J2000)
ROLL:            248.053d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75468.41 SOD {20:57:48.41} UT,   89.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     404859479
X_OFFSET:        801 [pixels]
Y_OFFSET:        1035 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       961
Y_GRB_POS:       1195
BINNING_INDEX:   1
IM_URL:          sw00576238000msuni0101.fits
SUN_POSTN:       215.24d {+14h 20m 59s}  -14.05d {-14d 02' 42"}
SUN_DIST:        126.76 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.77d {+11h 23m 04s}   -0.19d {-00d 11' 36"}
MOON_DIST:       172.21 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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:     Wed 30 Oct 13 21:02:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.066d {+23h 00m 16s} (J2000)
POINT_DEC:        -5.390d {-05d 23' 24"} (J2000)
ROLL:            248.053d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75468.41 SOD {20:57:48.41} UT,   89.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     404859479
X_OFFSET:        801 [pixels]
Y_OFFSET:        1035 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       961
Y_GRB_POS:       1195
BINNING_INDEX:   1
IM_URL:          sw00576238000msuni0101.fits
SUN_POSTN:       215.24d {+14h 20m 59s}  -14.05d {-14d 02' 42"}
SUN_DIST:        126.76 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.77d {+11h 23m 04s}   -0.19d {-00d 11' 37"}
MOON_DIST:       172.20 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.76 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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:     Wed 30 Oct 13 21:03:19 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     69101,   Seg_Num: 0
GRB_RA:          345.080d {+23h 00m 19s} (J2000),
                 345.259d {+23h 01m 02s} (current),
                 344.432d {+22h 57m 44s} (1950)
GRB_DEC:          -5.389d {-05d 23' 20"} (J2000),
                  -5.315d {-05d 18' 52"} (current),
                  -5.658d {-05d 39' 27"} (1950)
GRB_DATE:        16595 TJD;   303 DOY;   13/10/30
GRB_TIME:        75378.80 SOD {20:56:18.80} UT
TRIGGER_INDEX:   147
GRB_PHI:         132.52 [deg]
GRB_THETA:        32.58 [deg]
DELTA_TIME:      2281.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    0.00 [sigma]
LC_URL:          sw00576238000msb.lc
SUN_POSTN:       215.25d {+14h 20m 59s}  -14.05d {-14d 02' 43"}
SUN_DIST:        126.77 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.77d {+11h 23m 06s}   -0.20d {-00d 11' 47"}
MOON_DIST:       172.21 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.36,-55.77 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      344.18,  0.91 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        WARNING: No BAT_Position TDRSS message was received for this trigger_number!  
COMMENTS:           
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 8.38,-1.55 [deg].  
COMMENTS:        The 3rd packet (of 3) was missing in the lightcurve data stream.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 21:04:50 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     576238,   Seg_Num: 0
GRB_RA:          345.0672d {+23h 00m 16.12s} (J2000),
                 345.2462d {+23h 00m 59.09s} (current),
                 344.4196d {+22h 57m 40.70s} (1950)
GRB_DEC:          -5.3680d {-05d 22' 04.8"} (J2000),
                  -5.2936d {-05d 17' 36.8"} (current),
                  -5.6366d {-05d 38' 11.7"} (1950)
GRB_ERROR:       0.7 [arcsec radius, statistical only]
GRB_MAG:         14.97 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75467.00 SOD {20:57:47.00} UT,   88.2 [sec] since BAT Trigger Time
SUN_POSTN:       215.25d {+14h 20m 59s}  -14.05d {-14d 02' 44"}
SUN_DIST:        126.76 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.79d {+11h 23m 09s}   -0.20d {-00d 12' 03"}
MOON_DIST:       172.20 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.37,-55.74 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      344.18,  0.93 [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 9.0 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 21:07:28 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 15"} (J2000)
POINT_ROLL:      248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75680.56 SOD {21:01:20.56} UT,   301.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.873
N_STARS:         75
X_OFFSET:        481 [pixels]
Y_OFFSET:        715 [pixels]
X_MAX:           1440 [pixels]
Y_MAX:           1674 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00576238000msufc0301.fits
SUN_POSTN:       215.25d {+14h 21m 00s}  -14.05d {-14d 02' 46"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.81d {+11h 23m 14s}   -0.21d {-00d 12' 31"}
MOON_DIST:       172.16 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 21:07:49 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 15"} (J2000)
POINT_ROLL:      248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75680.56 SOD {21:01:20.56} UT,   301.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.873
N_STARS:         75
X_OFFSET:        481 [pixels]
Y_OFFSET:        715 [pixels]
X_MAX:           1440 [pixels]
Y_MAX:           1674 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw00576238000msufc0301.fits
SUN_POSTN:       215.25d {+14h 21m 00s}  -14.05d {-14d 02' 47"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.81d {+11h 23m 15s}   -0.21d {-00d 12' 35"}
MOON_DIST:       172.16 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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:     Wed 30 Oct 13 21:08:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 15"} (J2000)
ROLL:            248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75680.56 SOD {21:01:20.56} UT,   301.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     404859691
X_OFFSET:        801 [pixels]
Y_OFFSET:        1035 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       961
Y_GRB_POS:       1195
BINNING_INDEX:   1
IM_URL:          sw00576238000msuni0313.fits
SUN_POSTN:       215.25d {+14h 21m 00s}  -14.05d {-14d 02' 47"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.82d {+11h 23m 17s}   -0.21d {-00d 12' 47"}
MOON_DIST:       172.15 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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:     Wed 30 Oct 13 21:09:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 15"} (J2000)
ROLL:            248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  75680.56 SOD {21:01:20.56} UT,   301.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     404859691
X_OFFSET:        801 [pixels]
Y_OFFSET:        1035 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       961
Y_GRB_POS:       1195
BINNING_INDEX:   1
IM_URL:          sw00576238000msuni0313.fits
SUN_POSTN:       215.25d {+14h 21m 00s}  -14.05d {-14d 02' 48"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.82d {+11h 23m 18s}   -0.21d {-00d 12' 49"}
MOON_DIST:       172.15 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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 #15402
E. Troja (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), J. R. Cummings (NASA/UMBC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (PSU), C. B. Markwardt (NASA/GSFC), A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), C. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team:
At 20:56:18 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 131030A (trigger=576238). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 345.080, -5.389 which is
```
   RA(J2000) = 23h 00m 19s
   Dec(J2000) = -05d 23' 20"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed multiple peaks structure with a duration of about 45 sec. The peak count rate was ~31500 counts/sec (15-350 keV), at ~6 sec after the trigger.
The XRT began observing the field at 20:57:37.1 UT, 78.4 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 345.0657, -5.3659 which is equivalent to:
```
   RA(J2000)  = +23h 00m 15.77s
   Dec(J2000) = -05d 21' 57.2"
```
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This location is 97 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
The initial flux in the 0.1 s image was 5.43e-08 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 89 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	23:00:16.13 = 345.06720
  DEC(J2000) = -05:22:05.1  =  -5.36808
```
with a 90%-confidence error radius of about 0.74 arc sec. This position is 9.5 arc sec. from the center of the XRT error circle. The estimated magnitude is 14.97 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06.
Burst Advocate for this burst is E. Troja (eleonora.troja 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:     Wed 30 Oct 13 21:13:57 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 16"} (J2000)
POINT_ROLL:      248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  76259.67 SOD {21:10:59.67} UT,   880.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.732
N_STARS:         129
X_OFFSET:        241 [pixels]
Y_OFFSET:        475 [pixels]
X_MAX:           1680 [pixels]
Y_MAX:           1914 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00576238000msufc0880.fits
SUN_POSTN:       215.25d {+14h 21m 01s}  -14.05d {-14d 02' 52"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.86d {+11h 23m 27s}   -0.23d {-00d 13' 41"}
MOON_DIST:       172.11 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 30 Oct 13 21:14:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 16"} (J2000)
POINT_ROLL:      248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  76259.67 SOD {21:10:59.67} UT,   880.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.732
N_STARS:         129
X_OFFSET:        241 [pixels]
Y_OFFSET:        475 [pixels]
X_MAX:           1680 [pixels]
Y_MAX:           1914 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw00576238000msufc0880.fits
SUN_POSTN:       215.25d {+14h 21m 01s}  -14.05d {-14d 02' 52"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.87d {+11h 23m 28s}   -0.23d {-00d 13' 45"}
MOON_DIST:       172.11 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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:     Wed 30 Oct 13 21:15:23 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 16"} (J2000)
ROLL:            248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  76259.67 SOD {21:10:59.67} UT,   880.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     404860270
X_OFFSET:        800 [pixels]
Y_OFFSET:        1034 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       960
Y_GRB_POS:       1194
BINNING_INDEX:   1
IM_URL:          sw00576238000msuni0892.fits
SUN_POSTN:       215.25d {+14h 21m 01s}  -14.05d {-14d 02' 53"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.88d {+11h 23m 30s}   -0.23d {-00d 13' 57"}
MOON_DIST:       172.10 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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:     Wed 30 Oct 13 21:15:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     576238,   Seg_Num: 0
POINT_RA:        345.064d {+23h 00m 15s} (J2000)
POINT_DEC:        -5.388d {-05d 23' 16"} (J2000)
ROLL:            248.055d
IMG_START_DATE:  16595 TJD;   303 DOY;   13/10/30
IMG_START_TIME:  76259.67 SOD {21:10:59.67} UT,   880.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     404860270
X_OFFSET:        800 [pixels]
Y_OFFSET:        1034 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       960
Y_GRB_POS:       1194
BINNING_INDEX:   1
IM_URL:          sw00576238000msuni0892.fits
SUN_POSTN:       215.25d {+14h 21m 01s}  -14.05d {-14d 02' 53"}
SUN_DIST:        126.75 [deg]   Sun_angle= -8.7 [hr] (East of Sun)
MOON_POSTN:      170.88d {+11h 23m 31s}   -0.23d {-00d 14' 01"}
MOON_DIST:       172.10 [deg]
MOON_ILLUM:      15 [%]
GAL_COORDS:       67.34,-55.75 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      344.17,  0.91 [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 #15403
Petr Kub=C3=A1nek (Porsche Engineering Services s.r.o. & Institute of Physics, Czech Republic), Martin Topinka, Lorraine Hanhol, Seamus Meehan (UCD, Ireland) reports on behalf of wider collaboration:
Watcher telescope at Boyden Observatory, South Africa, running RTS2 observatory control system, started automatic observation of GRB 131030A (GCN 15402, E.Troja et.al.) at 20:57:24.070 UT. On image acquired on 20:58:49.830 UT, e.g. 171s post GRB, we clearly identify optical counterpart mentioned at the above GCN.
Futher observations, as well as analysis, are ongoing.
GCN Circular #15405
E. Gorbovskoy, V. Lipunov, D. Denisenko, V. Kornilov, A. Kuznetsov, D. Kuvshinov, N. Tyurina, N. Shatskiy, P. Balanutsa, D. Zimnukhov, V.V. Chazov Lomonosov Moscow State University, Sternberg Astronomical Institute
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V. Sennik Kislovodsk Solar Station of the Pulkovo Observatory
K. Ivanov, S. Yazev, N.M. Budnev, O. Gres, O. Chuvalaev, V.A. Poleshchuk Irkutsk State University
V. Yurkov, Yu. Sergienko, D. Varda, E. Sinyakov Blagoveschensk Educational State University, Blagoveschensk
V. Krushinski, I. Zalozhnich, A. Popov, A. Bourdanov Ural Federal University
H. Levato and C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
C. Mallamaci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB131030A 50 min (3000s) after GRB time at 2013-10-30 21-46-10.273 UT. On our first (180 sec) images we found optical transient within SWIFT error-box (E. Troja et. al GCN15402). The unfiltred magnitude is 16.5; The 5-sigma upper limit has been about 19.0 mag. So long pointing time was due to with daily power cut on the observatory. The message may be cited.
GCN Circular #15406
F.J. Virgili, C.G. Mundell (LJMU), J. Japelj, A. Gomboc (U. Ljubljana), R.J. Smith (LJMU), A. Melandri (INAF-OAB) report:
The 2-m Liverpool Telescope robotically followed up GRB 131030A (Swift Trigger 576238; Troja et al. GCN 15402) immediately after the GRB trigger time. The automated procedure detected an uncatalogued source at the location of the UVOT source. We confirm the fading nature of the object with
R =3D 16.9 =B1 0.2 mag (vs. USNOB1) 34.8 min after the burst.
thereby confirming this as the GRB afterglow.
Observations and analysis are ongoing.
GCN Circular #15407
D. Xu, J. P. U. Fynbo (DARK/NBI), P. Jakobsson, Z. Cano (U. Iceland), B. Milvang-Jensen, D. Malesani (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI) & M. Hayes (Stockholm University) report on behalf of a larger collaboration:
We observed the optical afterglow of GRB 131030A (Troja et al., GCN 15402) with the NOT equipped with the AlFOSC instrument. The transient is clearly detected in our acquisition image with a magnitude R ~ 17 at a mean time of 0.569 hr after the GRB.
A single spectrum of 1200 s covering the range from 3800 to 8000 AA was obtained with a mean epoch of 0.894 hr after the burst. The spectrum displays a strong continuum with features of Fe II, Mg II and Al II at a common redshift of z = 1.293 (wavelength calibration based on archival data), which we identify as the redshift of the GRB. We also detect an intervening system at z = 1.16 displaying Fe II and Mg II.
GCN Circular #15408
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), R. Sanchez-Ramirez (IAA-CSIC), J. Gorosabel (IAA-CSIC), J.P.U. Fynbo (DARK/NBI), N.R. Tanvir (U. Leicester) and C.A. Alvarez Iglesias (ULL/IAC) report on behalf of a larger collaboration:
We have observed the afterglow of GRB131030A (Troja et al. GCN 15402) with the 10.4m GTC telescope at Roque de los Muchachos Observatory (Spain) starting at 21:50 UT (54 min after the burst). We used the R2000B grism that covers the range from 3950 to 5700 A at a resolution of ~2200.
A single 600s exposure reduced with archive calibrations shows a strong trace with absorption features of AlIII, ZnII, CrII, NiII, FeII, NiII* and FeII* at a common redshift of z=1.295, which we identify as the redshift of the GRB. An additional intervening system is seen at z=1.164, with lines of AlIII, FeII and MnII.
GCN Circular #15410
Jan Strobl (1,3), Martin Jelinek (2), Cyril Polasek (1), Michal Jakubec (1), Petr Skala (1,3) and Rene Hudec (1,3) (1. AI ASCR Ondrejov, 2. IAA CSIC Granada, 3. FEE CTU Prague)
We observed the field of the Swift GRB 131030A (Troja et al., GCNC 15402) with the 0.5m telescope D50 and 0.25m telescope BART in Ondrejov (Czech Republic), starting at 20:57:16 UT, i.e. 56s after the trigger.
The optical afterglow (Virgili et al, GCNC 15406) is clearly detected in our images. After an initial peak of about 13.8m (unfiltered, calibrated using USNO-B R-band) the lightcurve decays with \alpha~0.9.
This message can be cited.
GCN Circular #15411
V. Terron (IAA/CSIC), M. Fernandez (IAA/CSIC), J. Gorosabel (IAA/CSIC-UPV/EHU), report on behalf of a larger collaboration:
We imaged the GRB131030A (GCNC 15402) optical afterglow (GCNC 15403, 15405, 14506, 15410) with the 1.23m CAHA telescope. Two BVRI-band series were taken starting 2.01 hr post burst. The optical afterglow is well detected in the four bands at a level of R~18.0 (Vega), calibrated against the USNO B1.0 catalog.
GCN Circular #15412
A. S. Moskvitin, reports on behalf of SAO RAS GRB follow-up team:
We observed the field of GRB 131030A (Troja et al., GCN#15402) with the 1-meter telescope Zeiss-1000 of Special Astrophysical Observatory of RAS in four bands: B, V, Rc, Ic. Observations were started since 23 minutes after the Swift trigger. The weather conditions were excellent, but the air masses of the object was about 3-6.
Optical counterpart was clearly detected at all images. Preliminary results of Rc band photometry are as following:
```
T_mid, UT   T - T0, h   exposure, s   R mag   +/- error
21:18:45    0.374        60           16.55 +/- 0.02
21:34:05    0.630        60           17.09 +/- 0.03
21:44:14    0.799       120           17.26 +/- 0.02
21:56:27    1.003       120           17.39 +/- 0.03
22:07:26    1.186       120           17.53 +/- 0.03
22:21:30    1.420       360           17.63 +/- 0.02
22:30:08    1.564       480           17.69 +/- 0.03
```
The magnitudes were calibrated against the set of USNO B1 stars (R2) and not corrected for the Galaxy extinction. Rc band light curve and the first image is shown at ftp://ftp.sao.ru/pub/grb/GRB131030A/GRB131030A_image_LC.jpg
GCN Circular #15413
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 131030A (Swift-BAT trigger 576238: Troja, et al., GCN 15402) triggered Konus-Wind at T0=3D75377.811 s UT (20:56:17.811).
The burst light curve shows a multi-peaked pulse from ~T0-3 s till ~T0+25 s. The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB131030_T75377/
As observed by Konus-Wind, the burst had a fluence of (6.6 =B1 0.4)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+11.648 s, of (1.0 =B1 0.1)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+27.904 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -0.71 =B1 0.12, the high energy photon index beta =3D -2.95 =B1 0.28, the peak energy Ep =3D 177 =B1 10 keV, chi2 =3D 76/96 dof.
Assuming the redshift z=3D1.293 (Xu, et al., GCN 15407; de Ugarte Postigo, et al., GCN 15408), and a standard cosmology model with H_0 =3D 70 km/s/Mpc, Omega_M =3D 0.27, and Omega_Lambda =3D 0.73, we estimate the following rest-frame parameters: the isotropic energy release E_iso is (3.0 =B1 0.2)x10^53 erg, the peak luminosity L_iso is (1.0 =B1 0.1)x10^53 erg/s, and the rest-frame peak energy Ep,i =3D (406 =B1 22) keV
All the quoted values are preliminary.
GCN Circular #15414
A. A. Breeveld (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 131030A 90=20 s after the BAT trigger (Troja et al., GCN Circ. 15402). A fading source=20 consistent with the XRT position (Troja et al. GCN Circ. 15402) is=20 clearly detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
     RA  (J2000) =3D  23:00:16.14 =3D 345.06723 (deg.)
     Dec (J2000) =3D -05:22:05.2  =3D  -5.36811 (deg.)
```
with an estimated uncertainty of 0.50 arc sec. (radius, 90% confidence).
Preliminary detections using the UVOT photometric system (Breeveld et=20 al. 2011, AIP Conf. Proc. 1358, 373) for the finding chart (FC) and=20 other early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white_FC            90          239          148         14.87 =B1 0.02
white              582          601           20         16.13 =B1 0.05
u_FC               302          552          246         15.30 =B1 0.03
b                  557          577           20         16.30 =B1 0.08
v                  631          651           19         15.98 =B1 0.13
uvw1               681          701           19         16.42 =B1 0.17
uvm2               656          676           20         16.63 =B1 0.24
uvw2               606          626           20         17.97 =B1 0.36
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) =3D 0.06 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #15416
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 2695 s of XRT Photon Counting mode data and 7 UVOT images for GRB 131030A, 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 = 345.06732, -5.36845 which is equivalent to:
```
RA (J2000): 23h 00m 16.16s
Dec (J2000): -05d 22' 06.4"
```
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 #15417
A. Melandri (INAF-OAB), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), B. Sbarufatti (INAF-OAB/PSU), P. D'Avanzo (INAF-OAB) and E. Troja report on behalf of the Swift-XRT team:
We have analysed 6.9 ks of XRT data for GRB 131030A (Troja et al. GCN Circ. 15402), from 68 s to 41.4 ks after the BAT trigger. The data comprise 1.0 ks 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 Evans et al. (GCN. Circ 15416).
The late-time light curve (from T0+4.3 ks) can be modelled with a power-law decay with a decay index of alpha=1.18 (+0.06, -0.07).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.11 (+/-0.03). The best-fitting absorption column is 1.17 (+/-0.07) x 10^21 cm^-2, in excess of the Galactic value of 4.7 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.09 (+0.13, -0.12) and a best-fitting absorption column of 1.16 (+0.30, -0.28) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.16 (+0.30, -0.28) x 10^21 cm^-2
Galactic foreground: 4.7 x 10^20 cm^-2
Excess significance: 4.0 sigma
Photon index:	     2.09 (+0.13, -0.12)
```
If the light curve continues to decay with a power-law decay index of 1.18, the count rate at T+24 hours will be 0.055 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.9 x 10^-12 (2.6 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/00576238.
This circular is an official product of the Swift-XRT team.
GCN Circular #15418
Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report:
We have detected GRB 131030A optical afterglow at iTelescope observatory T21 (Mayhill, New Mexico). We used 0.43-m/6.8 astrograph and FLI-PL6303E CCD. Three unfiltered images and three photometric R filter images with 600 sec exposure time were made.
The afterglow was detected at the following position RA 23:00:16.17 and DEC -05:22:05.0.
The following magnitudes were obtained from the observations using NOMAD1 0846-0702870 (R=17.120) as a comparison star:
```
Tmid(h)+T0       Filter             Exp. time (sec)       Mag            Mag err. 
8.53                  unfiltered       3x600                   18.57CR     0.12
9.26                  R                  3x600                   19.43R        0.24
```
GCN Circular #15419
Klotz A. (IRAP-CNRS-OMP), Gendre B. (ARTEMIS), Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 131030A detected by SWIFT (trigger 576238, Troja et al. GCN 15402) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile.
The observations started 2.85h after the GRB trigger. The elevation of the field increased from 59 degrees above horizon and weather conditions were good.
We clearly detected the fading counterpart mentioned by previous teams (Virgili et al., GCN 15406, Strob et al. GCN 15410) from T0+2.85h to T0+9.13h
This message may be cited.
GCN Circular #15420
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 131030A (Troja, et al., GCN 15402) 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 2013/10 31.08 to 2013/10 31.37 UTC (4.91 to 11.97 hours after the BAT trigger), obtaining a total of 4.26 hours exposure in the r and i bands and 1.69 hours exposure in the Z, Y, J, and H bands.
We detect the uncatalogued source reported by UVOT (Troja et al., GCN Circ. 15414). In comparison with the SDSS DR9 and 2MASS, we obtain the following detections:
```
  r     19.14 +/- 0.01
  i     18.92 +/- 0.01
  Z     18.76 +/- 0.02
  Y     18.61 +/- 0.02
  J     18.62 +/- 0.02
  H     18.40 +/- 0.02
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We can confirm that this source fades during our observations with power-law decay indices of approximate= ly t^-0.9 in the r, i, Z and Y bands and a shallower decay of t^-0.5 and t^-0.4 in the J and H bands, respectively.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr= o M=E1rtir.
GCN Circular #15423
D. A. Perley (Caltech) and S. B. Cenko (NASA/GSFC) report on behalf of a larger collaboration:
We observed the afterglow of GRB 131030A (GCN 15402, Troja et al.) with the robotic Palomar 60-inch telescope in the g, r, i, and z filters. Three exposures of 180 seconds each were acquired in each filter at four separate epochs starting at 5.09, 6.63, 8.12, and 9.65 hours after the Swift trigger, respectively. The light curve in these bands shows a steady power-law decline with decay index alpha~0.95, similar to that reported by RATIR over the same timescale (GCN 15420, Littlejohns et al.)
Photometry from the first epoch (calibrated relative to SDSS) yields:
```
t_mid(d) exp(s) filter   magnitude
0.21434  3x180    g  = 19.14 +/- 0.02
0.21912  3x180    r  = 18.81 +/- 0.02
0.22391  3x180    i  = 18.61 +/- 0.03
```
GCN Circular #15425
L. P. Xin, J. Y. Wei, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han and C. Wu on behalf of EAFON report:
We began to observe GRB 131030A (Troja et al. GCN 15402) with Xinglong 0.8-m TNT telescope at 13:59:04 (UT) , Oct. 31th, about 17 hours after the burst. 10*300 sec R-band images were obtained.
The optical counterpart (Troja et al. GCN 15402) was clearly detected with a magnitude of 19.4+/-0.1 mag in R band, calibrated by USNO B1.0 R2mag at the mean time of 17.397h after the burst.
This message may be cited.
GCN Circular #15427
U.Quadri, L.Strabla and R.Girelli report:
We imaged the field of GRB 131030A detected by SWIFT (trigger 576238,Troja et al. GCN 15402) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy.
The observations started 20h 11m. after the GRB trigger,with our schmidt telescope D=320 mm F/D=3.1.
Weather conditions were good.
We co-added a series of 30 unfiltered CCD exposures of 120sec.
We detect a (fading) afterglow in the error box given by SWIFT. at the following position (+/- 3 arcsec):
```
RA (J2000.0) =  23h 00m 16.12s
DEC(J2000.0) = -05d 22p 06.9s
```
The results of our photometry are:
```
    Date        UT        Vmag   +/- err  
               Middle    

2013-10-31   17:40:39     19.17    0.21
2013-10-31   18:22:02     19.62    0.28
2013-10-31   19:04:46     20.45    0.22
```
Magnitudes were estimated with the USNO-B1 cat. and are not corrected for galactic dust extinction.
The message may be cited.
GCN Circular #15430
M. Balokovic, T. Hovatta, O. King, T. Pearson, A. Readhead Caltech, USA
D. Blinov, N. Kylafis, G. Panopoulou, I. Papadakis, I. Papamastorakis, V. Pavlidou, P. Reig, K. Tassis University of Crete/FORTH, Greece
P. Khodade, C. Rajarshi, A. Ramaprakash, R. Rouneq Inter-University Centre for Astronomy and Astrophysics, India
E. Angelakis, I. Myserlis, L. Fuhrmann, J. A. Zensus Max Planck Institute for Radio Astronomy, Germany
R. Feiler, A. Kus, B. Pazderska, E. Pazderski Nicolaus Copernicus University, Poland
We observed GRB 131030A (Swift Trigger 576238; Troja et al. GCN 15402) using the RoboPol (http://robopol.org) polarimeter on the 1.3m Skinakas observatory telescope (Greece). We confirm the presence of an uncatalogued source at the location (RA=23h00m16s, Dec=-05d22m05s). Preliminary analysis showed that emission of the source is linearly polarized at high significance.
Further analysis will be presented elsewhere.
[GCN OPS NOTE(01nov13): This was delayed in distribution by 17 hours because a new entry in the list had to be added.]
GCN Circular #15432
Myungshin Im and Changsu Choi (CEOU/Seoul National Univ.), on behalf of a larger collaboration:
We observed GRB 131030A (Troja et al., GCN 15402) in B,R band using a 1-m telescope at Mt. Lemmon Optical Observatory (LOAO) in Arizona, US.
The observation started at 2013-10-31 01:42:46 UT, or about 4.78 hours after the BAT alert.
In all of the BR images, we identify the afterglow, with approximate magnitudes B ~ 19.29 +/-0.07, R ~ 18.88 +/- 0.09 mag (first epoch), calibrated against stars in vicinity based on USNO-B1 photometry.
We also confirm fading of the object from serial set of data we took about 4 and 6 hours later.
Further observations are planned.
We thank the LOAO operator, Jae-Hyuk Yoon and In-Kyung Baek for performing the observation.
[GCN OPS NOTE(01nov13): This was delayed in distribution by 8 hours because a new entry had to be added to the list.]
GCN Circular #15435
A. S. Moskvitin and T. N. Sokolova report on behalf of SAO RAS GRB follow-up team:
We observed the GRB 131030A field (Troja et al., GCN#15402) on October, 31, with the 1-m telescope Zeiss-1000 of SAO RAS. The weather conditions were good. The observations were carried out in three bands: B, V, Rc.
We clearly detected the OT at the level R = 20.4 +/- 0.1. T_start = 18:16:11 UT, T_end = 21:59:15 UT, T_mid - T0 = 24.059 hours. The total Rc-band exposure was 3000 seconds.
The OT magnitude was calibrated against the same set of USNO B1 stars (R2) as in GCN #15412 and not corrected for the Galaxy extinction.
GCN Circular #15436
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We again observed the field of GRB 131030A (Troja, et al., GCN 15402) wit= h the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacio= nal on Sierra San Pedro M=E1rtir from 2013/11 1.08 to 2013/11 1.20 UTC (29.01= to 31.91 hours after the BAT trigger), obtaining a total of 2.13 hours expos= ure in the r and i bands and 0.88 hours exposure in the Z, Y, J, and H bands.
We continue to detect the uncatalogued source reported by UVOT (Troja et al., GCN Circ. 15414), at fainter magnitudes than the first epoch of RATI= R observations (Littlejohns et al., GCN Circ. 15420). In comparison with th= e SDSS DR9 and 2MASS, we obtain the following detections:
```
  r     20.73 +/- 0.03
  i     20.45 +/- 0.03
  Z     20.19 +/- 0.05
  Y     20.06 +/- 0.07
  J     20.07 +/- 0.08
  H     19.57 +/- 0.11
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. In comparison with the first epoc= h of RATIR observations these magnitudes can be modelled with power-law decays, with indices of approximately t^-1.1 for the r and i bands, t^-1.= 0 for the Z, Y and J bands and t^-0.8 for the H band.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr= o M=E1rtir.
GCN Circular #15444
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We again observed the field of GRB 131030A (Troja, et al., GCN Circ. 15402) 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 2013/11 4.10 to 2013/11 4.17 UTC (101.35 to 103.16 hours after the BAT trigger), obtaining a total of 1.04 hours exposure in the r and i bands and 0.29 hours exposure in the Z, Y, J, and H bands.
We continue to detect the uncatalogued source reported by UVOT (Troja et al., GCN Circ. 15414) in the r, i and Z bands, at fainter magnitudes than the previous epochs of RATIR observations (Littlejohns et al., GCN Circ. 15436; Littlejohns et al., GCN Circ. 15420). For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 and 2MASS, we obtain the following detections and upper limits (3-sigma):
```
  r     22.48 +/- 0.13
  i     22.71 +/- 0.30
  Z     21.70 +/- 0.34
  Y     > 21.28
  J     > 21.05
  H     > 20.49
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. In comparison with the second epo= ch of RATIR observations the source has faded by an average of 1.8 magnitude= s in the r, i and Z bands. The upper limits all indicate that the source ha= s faded by a minimum of approximately 1 magnitude in the Y, J and H bands. Our observations in the Z, Y, J and H bands are consistent with the previously reported power-law decay indices (Littlejohns et al., GCN Circ. 15436), however, there is indication of a steeper decay in both the r and i bands. Between this and the second epoch of RATIR observations we find power-laws of t^-1.33 for the r band and t^-1.72 for the i band.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr= o M=E1rtir.
GCN Circular #15456
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), J. Tueller (GSFC), T. N. Ukwatta (MSU) (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 131030A (trigger #576238) (Troja, et al., GCN Circ. 15402). The BAT ground-calculated position is RA, Dec = 345.074, -5.380 deg which is
```
   RA(J2000)  =  23h 00m 17.8s 
   Dec(J2000) = -05d 22' 46.4" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 37%.
The mask-weighted light curve shows at least two overlapping peaks starting at ~T-8 sec, peaking at ~T+10 sec, and ending at ~T+180 sec with a low-level tail out to at least T+800 sec. T90 (15-350 keV) is 41.1 +- 4.0 sec (estimated error including systematics).
The time-averaged spectrum from T-6.04 to T+143.37 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.30 +- 0.03. The fluence in the 15-150 keV band is 2.9 +- 0.0 x 10^-05 erg/cm2. The 1-sec peak photon flux measured from T+6.40 sec in the 15-150 keV band is 28.1 +- 0.7 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/576238/BA/
GCN Circular #15462
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We again observed the field of GRB 131030A (Troja, et al., GCN Circ. 15402) 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 2013/11 5.08 to 2013/11 5.34 UTC (124.95 to 131.33 hours after the BAT trigger), obtaining a total of 4.24 hours exposure in the r and i bands and 0.92 hours exposure in the Z, Y, J, and H bands.
We continue to detect the previously reported source in the r and i bands (Littlejohns, et al., GCN Circ. 15420; Troja, et al., GCN Circ. 15402). For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 and 2MASS, we obtain the following detections and upper limits (3-sigma):
```
  r     23.17 +/- 0.14
  i     22.73 +/- 0.14
  Z     > 22.82
  Y     > 22.35
  J     > 20.05
  H     > 19.38
```
A further epoch of observations was also conducted from 2013/11 6.09 to 2013/11 6.34 UTC (149.15 to 155.17 hours after the BAT trigger), obtaining a total of 3.73 hours exposure in the r and i bands and 1.53 hours exposure in the Z, Y, J, and H bands. The source was detected in the r and i bands once more. For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 and 2MASS, we obtain the following detections and upper limits (3-sigma):
```
  r     23.41 +/- 0.18
  i     23.06 +/- 0.18
  Z     > 22.74
  Y     > 22.25
  J     > 21.97
  H     > 21.39
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. In comparison with previous epochs of RATIR observations, the source continues to fade in both the r and i band.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr= o M=E1rtir.
GCN Circular #15463
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We again observed the field of GRB 131030A (Troja, et al., GCN Circ. 15402) 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 2013/11 7.09 to 2013/11 7.33 UTC (173.34 to 178.87 hours after the BAT trigger), obtaining a total of 3.40 hours exposure in the r and i bands and 1.41 hours exposure in the Z, Y, J, and H bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 and 2MASS, we obtain the following upper limits (3-sigma):
```
  r     > 23.52
  i     > 23.11
  Z     > 22.69
  Y     > 22.17
  J     > 21.87
  H     > 21.35
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The upper limits obtained in the r and i bands are consistent with the reported decay from previous epochs of RATIR observations (Littlejohns, et al., GCN Circ. 15462).
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr= o M=E1rtir.
GCN Circular #15481
T.Tanigawa, T. Yoshii, K. Ito, Y. Saito, Y. Yano, R. Usui, Y. Tachibana,
S. Kurita, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 131030A (E. Troja et al., GCN Circular #15402) with the
optical three color (g, Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2013-10-31 09:37:51 UT ( 12.68h after the burst).
We detected the previously reported optical afterglow of GRB131013A (E. Troja et al., GCN Circular #15402) in the Rc and Ic band.
The measured magnitudes were listed below.
```
T0+[sec]     MID-UT        T-EXP[sec]              g'                          Rc                          Ic

-------------------------------------------------------------------------------------------------------------------------------------

43334       10:45:52        2940                >19.92                19.37+/-0.31          18.94+/-0.27

49357       12:14:44        5760                >20.72                20.05+/-0.30          19.25+/-0.24

57097       14:23:40        3780                >20.38                19.57+/-0.22          >19.51

-------------------------------------------------------------------------------------------------------------------------------------
```
T0+ : Elapsed time after the burst [sec]
T-EXP: Total Exposure time [sec]
We used GSC2.3 catalog for flux calibration.
GCN Circular #15501
S. B. Pandey, Brajesh Kumar and Y. C. Joshi (ARIES Nainital India, on behalf of larger Indian GRB collaboration)
We observed the Swift GRB 131030A field ( (Troja et al., GCN#15402) using 1.3m DFOT telescope at Devasthal, operated by ARIES Nainital, India. The observations were started at 16:25:47 UT on 2013-10-31. Two frames in each R_c and I_c bands with an exposure time of 300s each were obtained in good seeing conditions.
In our individual frames, we clearly detect the optical counterpart of GRB 131030A (GNC circular 15403, 15405, 14506, 15410). The preliminary photometry of co-added R_c (300sec x 2) and I_c (300sec x 2) frames yields following.
```
.................................................................
Time (MID-UT)  Exp (sec)  Filter   Magnitude
.................................................................
2013-10-31, 16:46:39 600    R_c 20.13 +/- 0.04
2013-10-31, 16:33:09 600     I_c 19.49 +/- 0.06
..................................................................
```
The photometry was performed in comparison to nearby USNO- B1 stars. This message may be cited.
1409.2417 from 9 Sep 14
O.G. King et al.: Early-time polarized optical light curve of GRB 131030A
We report the polarized optical light curve of a gamma-ray burst afterglow obtained using the RoboPol instrument. Observations began 655 seconds after the initial burst of gamma-rays from GRB131030A, and continued uninterrupted for 2 hours. The afterglow displayed a low, constant fractional linear polarization of $p = (2.1 \pm 1.6)\,\%$ throughout, which is similar to the interstellar polarization measured on nearby stars. The optical brightness decay is consistent with a forward-shock propagating in a medium of constant density, and the low polarization fraction indicates a disordered magnetic field in the shock front. This supports the idea that the magnetic field is amplified by plasma instabilities on the shock front. These plasma instabilities produce strong magnetic fields with random directions on scales much smaller than the total observable region of the shock, and the resulting randomly-oriented polarization vectors sum to produce a low net polarization over the total observable region of the shock.

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