Gamma-ray Burst 130907A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

 
TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Sat 07 Sep 13 21:40:37 UT 
NOTICE_TYPE:    INTEGRAL SPI ACS Trigger
TRIGGER_NUM:    6936,   Sub_Num: 0
GRB_INTEN:      9.05 [sigma]   
GRB_TIME:       77956.79 SOD {21:39:16.79} UT
GRB_DATE:       16542 TJD;   250 DOY;   13/09/07
COMMENTS:       INTEGRAL SPI_ACS GRB Trigger.
COMMENTS:       Time_Scale=2.0000 and Time_Error=1.0000.
COMMENTS:       The SPIACS lightcurve can be found at:
COMMENTS:       ftp://isdcarc.unige.ch/arc/FTP/ibas/spiacs/2013-09/2013-09-07T21-39-16.5617-19084-56208-0.lc

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:41:35 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     569992,   Seg_Num: 0
GRB_RA:          215.877d {+14h 23m 31s} (J2000),
                 216.007d {+14h 24m 02s} (current),
                 215.403d {+14h 21m 37s} (1950)
GRB_DEC:         +45.616d {+45d 36' 58"} (J2000),
                 +45.554d {+45d 33' 16"} (current),
                 +45.842d {+45d 50' 32"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2206 [cnts]    Image_Peak=177 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10427     E_range: 50-350 keV
BKG_INTEN:       149136 [cnts]
BKG_TIME:        78060.99 SOD {21:41:00.99} UT
BKG_DUR:         8 [sec]
GRB_DATE:        16542 TJD;   250 DOY;   13/09/07
GRB_TIME:        78072.83 SOD {21:41:12.83} UT
GRB_PHI:         -156.86 [deg]
GRB_THETA:         9.22 [deg]
SOLN_STATUS:     0x43
RATE_SIGNIF:     18.84 [sigma]
IMAGE_SIGNIF:    9.91 [sigma]
MERIT_PARAMS:     +1  +0  +0  -4  +3  +0  +0  +0 -52  +0 
SUN_POSTN:       166.57d {+11h 06m 18s}   +5.75d {+05d 44' 48"}
SUN_DIST:         58.36 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.55d {+12h 50m 11s}   -7.76d {-07d 45' 24"}
MOON_DIST:        57.31 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 64.00 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      189.20, 54.96 [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 during a high background rate interval.  
COMMENTS:        This trigger occurred at longitude,latitude = 176.28,18.56 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:42:58 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     569992,   Seg_Num: 0
GRB_RA:          215.8926d {+14h 23m 34.22s} (J2000),
                 216.0223d {+14h 24m 05.35s} (current),
                 215.4185d {+14h 21m 40.44s} (1950)
GRB_DEC:         +45.6094d {+45d 36' 33.8"} (J2000),
                 +45.5477d {+45d 32' 51.8"} (current),
                 +45.8356d {+45d 50' 08.2"} (1950)
GRB_ERROR:       5.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       6.33e-08 [erg/cm2/sec]
GRB_SIGNIF:      8.18 [sigma]
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78139.39 SOD {21:42:19.39} UT,   66.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.67 237.21 261.49 243.39
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       166.58d {+11h 06m 18s}   +5.75d {+05d 44' 47"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.56d {+12h 50m 14s}   -7.76d {-07d 45' 38"}
MOON_DIST:        57.31 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.30, 64.00 [deg] galactic lon,lat of the burst
ECL_COORDS:      189.22, 54.96 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.74 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:43:09 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     569992,   Seg_Num: 0
GRB_RA:          215.8926d {+14h 23m 34.2s} (J2000),
                 216.0223d {+14h 24m 05.3s} (current),
                 215.4185d {+14h 21m 40.4s} (1950)
GRB_DEC:         +45.6094d {+45d 36' 33.8"} (J2000),
                 +45.5477d {+45d 32' 51.8"} (current),
                 +45.8356d {+45d 50' 08.2"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       67 [cnts]
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78139.39 SOD {21:42:19.39} UT,   66.6 [sec] since BAT Trigger Time
CENTROID_X:      294.38,  raw= 294  [pixels]
CENTROID_Y:      316.12,  raw= 316  [pixels]
ROLL:            242.46 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   42.72
GRB_POS_XRT_Z:   -21.95
IMAGE_URL:       sw00569992000msxps_rw.img
SUN_POSTN:       166.58d {+11h 06m 18s}   +5.75d {+05d 44' 47"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.56d {+12h 50m 14s}   -7.76d {-07d 45' 40"}
MOON_DIST:        57.31 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.30, 64.00 [deg] galactic lon,lat of the burst
ECL_COORDS:      189.22, 54.96 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:43:28 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     569992,   Seg_Num: 0
GRB_RA:          215.8926d {+14h 23m 34.2s} (J2000),
                 216.0223d {+14h 24m 05.3s} (current),
                 215.4185d {+14h 21m 40.4s} (1950)
GRB_DEC:         +45.6094d {+45d 36' 33.8"} (J2000),
                 +45.5477d {+45d 32' 51.8"} (current),
                 +45.8356d {+45d 50' 08.2"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       67 [cnts]
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78139.39 SOD {21:42:19.39} UT,   66.6 [sec] since BAT Trigger Time
CENTROID_X:      294.38,  raw= 294  [pixels]
CENTROID_Y:      316.12,  raw= 316  [pixels]
ROLL:            242.46 [deg]
GAIN:            1
MODE:            2, Short Image mode
WAVEFORM:        134
EXPO_TIME:       0.10 [sec]
GRB_POS_XRT_Y:   42.72
GRB_POS_XRT_Z:   -21.95
IMAGE_URL:       sw00569992000msxps_rw.img
SUN_POSTN:       166.58d {+11h 06m 18s}   +5.75d {+05d 44' 46"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.56d {+12h 50m 15s}   -7.76d {-07d 45' 43"}
MOON_DIST:        57.31 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.30, 64.00 [deg] galactic lon,lat of the burst
ECL_COORDS:      189.22, 54.96 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:44:59 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     569992,   Seg_Num: 0
GRB_RA:          215.877d {+14h 23m 31s} (J2000),
                 216.007d {+14h 24m 02s} (current),
                 215.403d {+14h 21m 37s} (1950)
GRB_DEC:         +45.616d {+45d 36' 58"} (J2000),
                 +45.554d {+45d 33' 16"} (current),
                 +45.842d {+45d 50' 32"} (1950)
GRB_DATE:        16542 TJD;   250 DOY;   13/09/07
GRB_TIME:        78073.08 SOD {21:41:13.08} UT
TRIGGER_INDEX:   10427
GRB_PHI:         -156.86 [deg]
GRB_THETA:         9.22 [deg]
DELTA_TIME:      70.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x43
RATE_SIGNIF:     18.84 [sigma]
IMAGE_SIGNIF:    9.91 [sigma]
LC_URL:          sw00569992000msb.lc
SUN_POSTN:       166.58d {+11h 06m 19s}   +5.75d {+05d 44' 45"}
SUN_DIST:         58.36 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.58d {+12h 50m 18s}   -7.77d {-07d 45' 59"}
MOON_DIST:        57.31 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 64.00 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      189.20, 54.96 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred during a high background rate interval.  
COMMENTS:        This trigger occurred at longitude,latitude = 176.28,18.56 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:46:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.621d {+45d 37' 16"} (J2000)
POINT_ROLL:      242.458d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78147.19 SOD {21:42:27.19} UT,   74.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.008
N_STARS:         13
X_OFFSET:        544 [pixels]
Y_OFFSET:        504 [pixels]
X_MAX:           1503 [pixels]
Y_MAX:           1463 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00569992000msufc0074.fits
SUN_POSTN:       166.58d {+11h 06m 19s}   +5.75d {+05d 44' 44"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.59d {+12h 50m 21s}   -7.77d {-07d 46' 12"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:46:42 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.621d {+45d 37' 16"} (J2000)
POINT_ROLL:      242.458d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78147.19 SOD {21:42:27.19} UT,   74.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.008
N_STARS:         13
X_OFFSET:        544 [pixels]
Y_OFFSET:        504 [pixels]
X_MAX:           1503 [pixels]
Y_MAX:           1463 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw00569992000msufc0074.fits
SUN_POSTN:       166.58d {+11h 06m 19s}   +5.75d {+05d 44' 43"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.59d {+12h 50m 22s}   -7.77d {-07d 46' 17"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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:     Sat 07 Sep 13 21:49:12 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.621d {+45d 37' 16"} (J2000)
ROLL:            242.458d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78147.19 SOD {21:42:27.19} UT,   74.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     400282958
X_OFFSET:        793 [pixels]
Y_OFFSET:        779 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       939
BINNING_INDEX:   1
IM_URL:          sw00569992000msuni0086.fits
SUN_POSTN:       166.58d {+11h 06m 19s}   +5.74d {+05d 44' 41"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.61d {+12h 50m 27s}   -7.78d {-07d 46' 42"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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:     Sat 07 Sep 13 21:49:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.621d {+45d 37' 16"} (J2000)
ROLL:            242.458d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78147.19 SOD {21:42:27.19} UT,   74.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     400282958
X_OFFSET:        793 [pixels]
Y_OFFSET:        779 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       939
BINNING_INDEX:   1
IM_URL:          sw00569992000msuni0086.fits
SUN_POSTN:       166.58d {+11h 06m 19s}   +5.74d {+05d 44' 41"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.61d {+12h 50m 28s}   -7.78d {-07d 46' 45"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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:     Sat 07 Sep 13 21:52:29 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     569992,   Seg_Num: 0
GRB_RA:          215.8918d {+14h 23m 34.03s} (J2000),
                 216.0215d {+14h 24m 05.15s} (current),
                 215.4177d {+14h 21m 40.24s} (1950)
GRB_DEC:         +45.6075d {+45d 36' 27.0"} (J2000),
                 +45.5458d {+45d 32' 44.9"} (current),
                 +45.8337d {+45d 50' 01.3"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         15.55 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78146.00 SOD {21:42:26.00} UT,   73.2 [sec] since BAT Trigger Time
SUN_POSTN:       166.58d {+11h 06m 20s}   +5.74d {+05d 44' 38"}
SUN_DIST:         58.36 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.64d {+12h 50m 34s}   -7.79d {-07d 47' 16"}
MOON_DIST:        57.30 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.29, 64.00 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      189.23, 54.96 [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 7.2 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:53:51 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
POINT_ROLL:      242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78359.16 SOD {21:45:59.16} UT,   286.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.520
N_STARS:         10
X_OFFSET:        473 [pixels]
Y_OFFSET:        459 [pixels]
X_MAX:           1432 [pixels]
Y_MAX:           1418 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00569992000msufc0286.fits
SUN_POSTN:       166.58d {+11h 06m 20s}   +5.74d {+05d 44' 37"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.65d {+12h 50m 37s}   -7.79d {-07d 47' 30"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN Circular #15183
M. J. Page (UCL-MSSL), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL) and V. N. Yershov (UCL-MSSL) report on behalf of the Swift Team:
At 21:41:13 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130907A (trigger=569992). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 215.877, +45.616 which is
```
   RA(J2000) = 14h 23m 31s
   Dec(J2000) = +45d 36' 58"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex multi-peaked structure with a duration of about 120 sec. The peak count rate was ~60000 counts/sec (15-350 keV), at ~25 sec after the trigger.
The XRT began observing the field at 21:42:19.3 UT, 66.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 215.8926, 45.6094 which is equivalent to:
```
   RA(J2000)  = +14h 23m 34.22s
   Dec(J2000) = +45d 36' 33.8"
```
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 45 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 6.33e-08 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 74 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	14:23:34.03 = 215.89181
  DEC(J2000) = +45:36:27.1  =  45.60753
```
with a 90%-confidence error radius of about 0.61 arc sec. This position is 7.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 15.55 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is M. J. Page (m.page AT ucl.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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:54:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
POINT_ROLL:      242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78359.16 SOD {21:45:59.16} UT,   286.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.520
N_STARS:         10
X_OFFSET:        473 [pixels]
Y_OFFSET:        459 [pixels]
X_MAX:           1432 [pixels]
Y_MAX:           1418 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00569992000msufc0286.fits
SUN_POSTN:       166.58d {+11h 06m 20s}   +5.74d {+05d 44' 36"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.66d {+12h 50m 38s}   -7.79d {-07d 47' 35"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:55:06 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
ROLL:            242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78359.16 SOD {21:45:59.16} UT,   286.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     400283170
X_OFFSET:        793 [pixels]
Y_OFFSET:        779 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       939
BINNING_INDEX:   1
IM_URL:          sw00569992000msuni0298.fits
SUN_POSTN:       166.58d {+11h 06m 20s}   +5.74d {+05d 44' 36"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.66d {+12h 50m 39s}   -7.80d {-07d 47' 43"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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:     Sat 07 Sep 13 21:55:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
ROLL:            242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78359.16 SOD {21:45:59.16} UT,   286.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     400283170
X_OFFSET:        793 [pixels]
Y_OFFSET:        779 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       953
Y_GRB_POS:       939
BINNING_INDEX:   1
IM_URL:          sw00569992000msuni0298.fits
SUN_POSTN:       166.58d {+11h 06m 20s}   +5.74d {+05d 44' 35"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.67d {+12h 50m 40s}   -7.80d {-07d 47' 46"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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:     Sat 07 Sep 13 21:58:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
POINT_ROLL:      242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78937.78 SOD {21:55:37.78} UT,   864.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.587
N_STARS:         31
X_OFFSET:        233 [pixels]
Y_OFFSET:        219 [pixels]
X_MAX:           1672 [pixels]
Y_MAX:           1658 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00569992000msufc0864.fits
SUN_POSTN:       166.59d {+11h 06m 21s}   +5.74d {+05d 44' 32"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.70d {+12h 50m 47s}   -7.81d {-07d 48' 21"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 07 Sep 13 21:59:12 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
POINT_ROLL:      242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78937.78 SOD {21:55:37.78} UT,   864.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.587
N_STARS:         31
X_OFFSET:        233 [pixels]
Y_OFFSET:        219 [pixels]
X_MAX:           1672 [pixels]
Y_MAX:           1658 [pixels]
DET_THRESH:      16
PHOTO_THRESH:    9
SL_URL:          sw00569992000msufc0864.fits
SUN_POSTN:       166.59d {+11h 06m 21s}   +5.74d {+05d 44' 32"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.70d {+12h 50m 48s}   -7.81d {-07d 48' 25"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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:     Sat 07 Sep 13 22:00:23 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
ROLL:            242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78937.78 SOD {21:55:37.78} UT,   864.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     400283748
X_OFFSET:        792 [pixels]
Y_OFFSET:        778 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       952
Y_GRB_POS:       938
BINNING_INDEX:   1
IM_URL:          sw00569992000msuni0876.fits
SUN_POSTN:       166.59d {+11h 06m 21s}   +5.74d {+05d 44' 31"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.71d {+12h 50m 51s}   -7.81d {-07d 48' 38"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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:     Sat 07 Sep 13 22:00:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     569992,   Seg_Num: 0
POINT_RA:        215.893d {+14h 23m 34s} (J2000)
POINT_DEC:       +45.623d {+45d 37' 22"} (J2000)
ROLL:            242.455d
IMG_START_DATE:  16542 TJD;   250 DOY;   13/09/07
IMG_START_TIME:  78937.78 SOD {21:55:37.78} UT,   864.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     400283748
X_OFFSET:        792 [pixels]
Y_OFFSET:        778 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       952
Y_GRB_POS:       938
BINNING_INDEX:   1
IM_URL:          sw00569992000msuni0876.fits
SUN_POSTN:       166.59d {+11h 06m 21s}   +5.74d {+05d 44' 30"}
SUN_DIST:         58.37 [deg]   Sun_angle= -3.3 [hr] (East of Sun)
MOON_POSTN:      192.71d {+12h 50m 51s}   -7.81d {-07d 48' 41"}
MOON_DIST:        57.32 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       84.32, 63.99 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      189.21, 54.97 [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 #15184
E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, A.Sankovich Sternberg Astronomical Institute, Moscow State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB130907A 18 sec after notice time and 43 sec after GRB time at 2013-09-07 21:42:00 UT in two polarizations. On our first images we found optical transient within SWIFT error-box (Page et. al. GCN15183). The object approximate magnitude is about 15.0 mag. Observations are made at very long zenith distance z=86 deg.
The observations and reduction is continued. The message may be cited.
GCN Circular #15187
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. Xu (DARK/NBI), D. Malesani (DARK/NBI), J. Gorosabel (IAA-CSIC/UPV-EHU), P. Jakobsson (U. Iceland) and J. Kajava (NOT) report on behalf of a larger collaboration:
We observed the optical afterglow of GRB 130907A (Page et al., GCN 15183; Gorbovskoy et al., GCN 15184) with the NOT equipped with the AlFOSC spectrograph and camera. The transient is clearly detected in our acquisition images, taken in a clear filter, at the following coordinates:
```
RA(J2000) = 14:23:34.08
Dec(J2000) = +45:36:26.7
```
Using R-band values from nearby USNO stars, we get a magnitude R = 16.7 +- 0.1 at a mean time of 0.41 hr after the GRB, where the error is dominated by calibration uncertainties.
A single spectrum of 900 s covering the range from 3800 to 8000 AA, with a resolution of ~700, was obtained with a mean epoch of 0.598 hr after the burst. The spectrum presents a strong continuum with deep spectral features of AlIII, FeII, MgII and MgI at a common redshift of z=1.238 (wavelength calibration based on archival data), which we identify as the redshift of the GRB.
GCN Circular #15191
A. Trotter, J. Haislip, A. LaCluyze, J. Moore, N. Frank, D. Reichart, A. Smith, D. Caton, L. Hawkins, V. Hoette, D. Harper, R. Kron, K. Cudworth, E. Struble, R. Russell, T. Linder, T. Berger, H. T. Cromartie, R. Egger, A. Foster, K. Ivarsen, M. Maples, M. Nysewander, and J. A. Crain report:
Skynet observed the Swift/XRT localization of GRB 130907A (Page et al., GCN 15183, Swift trigger 569992) with the 14" telescope at the Appalachian State University Dark Sky Observatory (DSO-14) in NC, USA (R and I bands), and with the 41" telescope of Yerkes Observatory in WI, USA (r' and i' bands).
Starting at 2013-09-08, 00:43 UT (t=3.03h post-trigger) and continuing until 17:41 UT (t=35.5m-4.65h post-trigger), Skynet took a total of 42 160s exposures. We detect an uncatalogued optical source in stacked images at RA 14:23:34.03, Dec +45:36:26.7 (J2000.0), consistent with the afterglow position reported by de Ugarte Postigo et al. (GCN 15187), and ~8" south of the Swift-XRT localization. At t=3.4h post-trigger, R~19.6 mag. The time range of our observations is not sufficient to confirm whether the source is indeed fading.
A preliminary light curve is at: http://skynet.unc.edu/grb/grb130907a.png
R and I magnitudes are in the Vega system, and r' and i' are in the AB system, calibrated to 5 APASS stars in the field. Magnitudes have not been corrected for line-of-sight Milky Way dust extinction with expected E(B-V)=0.011 (Schlegel et al. 1998).
Skynet observations are ongoing.
GCN Circular #15192
William H. Lee (UNAM), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 130907A (Page et al., GCN 15183) 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 2013/09 8.14 to 2013/09 8.15 UTC (5.57 to 6.03 hours after the BAT trigger), obtaining a total of 0.36 hours exposure in the r and i bands and 0.15 hours exposure in the Z, Y, J, and H bands.
We detect a source at 14:23:34.01 +45:36:27.0 J2000 (+/- 0.5") with
```
  r =3D 20.01 +/- 0.03
  i =3D 19.30 +/- 0.02
  Z =3D 18.78 +/- 0.05
  Y =3D 18.48 +/- 0.06
  J =3D 18.13 +/- 0.06
  H =3D 17.63 +/- 0.05
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
This source is outside the Swift-XRT error circle, but is only 0.8 arcsec from the transient source reported by de Ugarte Postigo et al. (GCN 15187) and 0.2 arcsec from the transient source reported by Trotter et al. (GCN 15191). From the close positional coincidence and fading magnitudes (r of 16.7, 19.6, and 20.0), we conclude all three observations are of the optical transient.
The transient source is 0.5 arcsec from the faint galaxy SDSS J142333.95+453626.2, but is 1-2 magnitudes brighter in riZ.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #15193
A. Trotter, D. Reichart, J. Haislip, A. LaCluyze, K. McLin, L. Cominsky, A. B. Smith, D. Caton, L. Hawkins, V. Hoette, K. Cudworth, D. Harper, R. Kron, T. Linder, R. Russell, E. Struble, T. Berger, H. T. Cromartie, R. Egger, A. Foster, N. Frank, K. Ivarsen, M. Maples, J. Moore, M. Nysewander, and J. A. Crain report:
In Trotter et al. (GCN 15191), we reported Skynet observations of the Swift/XRT localization of GRB 130907A (Page et al., GCN 15183, Swift trigger 569992) with the 14" telescope at the Appalachian State University Dark Sky Observatory (DSO-14) in NC, USA (R and I bands), and with the 41" telescope of Yerkes Observatory in WI, USA (r' and i' bands). Skynet continued observing the field with the 14" GLAST Optical Robotic Telescope (GORT) at the Hume observatory in CA, USA.
From t=5.9h - 8.2h post-trigger, GORT took a total of 54x160s exposures in the R and I bands. We confirm a fading afterglow at the position reported by de Ugarte Postigo et al. (GCN 15187) and by Lee et al. (GCN 15192). The afterglow fades from I=18.1 mag at t=3.2h to I=19.2 mag at t=8.2h, consistent with a power-law index alpha~-0.9.
A preliminary light curve is at: http://skynet.unc.edu/grb/grb130907a_2.png
R and I magnitudes are in the Vega system, and r' and i' magnitudes are in the AB system, calibrated to 5 APASS stars in the field. Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.011 (Schlegel et al. 1998).
No further Skynet observations are scheduled.
GCN Circular #15194
S. Schmidl (TLS Tautenburg), D. A. Kann (MPE Garching), S. Klose, S. Stecklum, F. Ludwig (all TLS Tautenburg), and J. Greiner (MPE Garching) report:
We observed the field of the intense GRB 130907A (Swift trigger 569992, Page et al., GCN #15183) with the 1.34m Tautenburg Schmidt telescope.
Starting at 22:02:18 UT (21 minutes after the trigger), we obtained in total 3 x 120 sec Ic-band images and 12 Rc-band images of 120 sec and 60 sec exposure. Observations were obtained at high airmass of 2.6 - 3.2. The afterglow is clearly detected on all frames.
Using the star at RA (J2000) = 14:23:28.93, Dec. (J2000) = +45:37:33.65, for which we derive Rc = 15.10, Ic = 14.51 using SDSS magnitudes and the transformations of Lupton (2005), we derive preliminary magnitudes for the first image in each filter of:
```
Time (d)	Filter	mag	error
0.0152		Ic		15.26	0.03
0.0172		Rc		16.57	0.03
```
not corrected for the very small reddening of 0.01 mag along the line of sight (Schlegel et al. 1998).
We note Swift was slewing when GRB 130907A started, the extended raw BAT light curve (http://gcn.gsfc.nasa.gov/notices_s/sw00569992000msbx.gif) shows the GRB began about 120 seconds before Swift T_0. Adding this time to our observing times, we find the data is well-described by a single power- law decay with alpha = 1.39 +/- 0.02. The detection by Trotter et al. (GCN #15191) agrees excellently with the extrapolation of our data, while the RATIR detection (Lee et al., GCN #15192), after transforming to Vega mag, indicates that the decay has slowed, which is confirmed by Trotter et al. (GCN #15193). The very early detection by Gorbovskoy et al. (GCN #15184) lies several magnitudes under a back-extrapolation of our data.
We derive a very large Rc-Ic color of about 1.2 mag from the fit, indicating possible strong reddening (see also the Skynet light curve, GCN #15193, and the multicolor RATIR mags, GCN #15192), which would be in accordance with the very strong absorption lines detected by de Ugarte Postigo et al. (GCN #15187).
This message may be cited.
GCN Circular #15195
S. R. Oates (UCL-MSSL) and M. J. Page (UCL-MSSL) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 130907A 74 s after the BAT trigger (Page et al., GCN Circ. 15183). A source consistent with the XRT position (Page et al. GCN Circ. 15183) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
  RA  (J2000) =  14:23:34.04 = 215.89183 (deg.)
  Dec (J2000) = +45:36:27.1  =  45.60753 (deg.)
```
with an estimated uncertainty of 0.50 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white               74          224          147         15.45 +/- 0.02
v                  616          636           20         16.29 +/- 0.16
b                  542          562           20         16.78 +/- 0.12
u                  286          536          246         15.87 +/- 0.04
w1                 666         1113          117         18.54 +/- 0.31
m2		   641         1606          117         >19.2
w2                 592          786         38         >18.7
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #15196
G. Vianello (Stanford), D. Kocevski(NASA/Goddard), J. Racusin (NASA/Goddard), and V. Connaughton (UAH) report on behalf of the Fermi-LAT team:
On Sept. 8th, 2013, Fermi LAT detected high energy emission from GRB 130907A, which triggered Swift at T0 = 21:41:13 UT (GCN 15183).
Fermi was passing through the South Atlantic Anomaly around T0, therefore data taking was disabled and neither Fermi/GBM nor Fermi/LAT could trigger on the burst. Fermi exited the SAA and resumed data taking at ~T0+1300 s.
The burst was ~150 deg from the LAT boresight when Fermi resumed data taking, and entered the LAT FOV at ~T0+3400 s. A likelihood analysis in the time interval T0+3400 s - T0+20 ks (with a ~8000 s exposure) resulted in a detection of the source with a significance of ~6 sigma at the NOT position (GCN Circ. 15187).
In particular, a 55 GeV photon compatible with the position of the burst was observed at ~T0+18 ks.
The Fermi LAT point of contact for this burst is Daniel Kocevski (daniel.kocevski@nasa.gov).
The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN Circular #15198
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 11208 s of XRT Photon Counting mode data and 18 UVOT images for GRB 130907A, 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 = 215.89216, +45.60725 which is equivalent to:
```
RA (J2000): 14h 23m 34.12s
Dec (J2000): +45d 36' 26.1"
```
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 #15199
D.N. Burrows (PSU), J.A. Kennea (PSU), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), V. Mangano (PSU) and M.J. Page report on behalf of the Swift-XRT team:
We have analysed 20 ks of XRT data for GRB 130907A (Page et al. GCN Circ. 15183), from 70 s to 60.0 ks after the BAT trigger. The data comprise 3.7 ks in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 15198).
The late-time light curve (from T0+5.7 ks) can be modelled with a power-law decay with a decay index of alpha=1.686 (+0.017, -0.016).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.761 (+0.015, -0.014). The best-fitting absorption column is 1.96 (+0.05, -0.04) x 10^21 cm^-2, in excess of the Galactic value of 1.0 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.98 (+/-0.06) and a best-fitting absorption column of 1.85 (+0.17, -0.16) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (5.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.85 (+0.17, -0.16) x 10^21 cm^-2
Galactic foreground: 1.0 x 10^20 cm^-2
Excess significance: 17.7 sigma
Photon index:	     1.98 (+/-0.06)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00569992.
This circular is an official product of the Swift-XRT team.
GCN Circular #15200
A. Corsi (GWU) reports on behalf of a larger collaboration:
We imaged the position of GRB 130907A (Page et. al. GCN 15183) with the Karl G. Jansky Very Large Array (VLA) in K-band, starting at about 4 hours after the burst. A provisional reduction shows a source consistent with the location of the GRB optical afterglow reported by de Ugarte Postigo et al. (GCN 15187). At this time, we estimate a preliminary flux of about 1.2 mJy at 24.5 GHz.
Further observations are planned.
GCN Circular #15201
Veli-Pekka Hentunen, Markku Nissinen, Harri Vilokki and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report:
We have detected GRB 130907A optical afterglow at iTelescope observatory T21 (Mayhill, New Mexico) 0.43-m/6.8 astrograph and FLI-PL6303E CCD. Six unfiltered images and seven photometric R filter images with 300 sec were made.
The afterglow was detected at the following position RA 14:23:34.06 and DEC +45:36:27.1 J2000.
The following magnitudes were obtained from the observations using NOMAD1 1356-0257141 (R=15.220) as a comparison star:
```
Tmid(h)+T0     Filter             Exp. time     Mag             Mag err. 
4.70                 unfiltered        3x300         20.00CR       0.49
5.22                 R                   7x300         20.06R          0.47
5.77                 unfiltered        3x300         20.36CR       0.47
```
GCN Circular #15202
J. R. Cummings (GSFC/UMBC),S. D. Barthelmy (GSFC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), M. J. Page (UCL-MSSL),D. M. Palmer (LANL),T. Sakamoto (AGU), M. Stamatikos (OSU),J. Tueller (GSFC),T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130907A (trigger #569992) (Page, et al., GCN Circ. 15183). The BAT ground-calculated position is RA, Dec = 215.898, 45.602 deg which is
```
    RA(J2000)  =  14h 23m 35.5s
    Dec(J2000) = +45d 36' 08.0"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shows a very complicated structure with six main peaks from T-55 sec to T+95 sec. Each of these peaks shows several sub-peaks. The strongest peak is at ~T+57 sec. After T+95 sec, the count rate drops significantly, but doesn't return all the way to the background level. Then there is another weak, soft peak from T+210 sec to T+240 sec. This late peak is coincident with the start of a long flare seen in the XRT. There may be further BAT emission beyond the end of the currently available event data. T90 (15-350 keV) is 115.14 +- 0.67 sec (estimated error including systematics).
The time-averaged spectrum from T-50.7 to T+234.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.11 +- 0.02. The fluence in the 15-150 keV band is 1.2 +- 0.0 x 10^-4 erg/cm2. The 1-sec peak photon flux measured from T+57.66 sec in the 15-150 keV band is 25.6 +- 0.5 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/569992/BA/
GCN Circular #15203
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 intense GRB 130907A (Swift-BAT trigger 569992: Page, et al., GCN 15183; Cummings, et al., GCN 15202) triggered Konus-Wind at T0=3D77955.997 s UT (21:39:15.997), or ~118 s before the BAT trigger.
The burst light curve shows multiple bright, partially overlapped pulses from ~T0-4 s till ~T0+210~s. The emission is seen up to ~15 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130907_T77955/
As observed by Konus-Wind, the burst had a fluence of (7.9 =B1 0.5)x10-4 erg/cm2, and a 256-ms peak flux, measured from T0+139.008 s, of (2.2 =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+206.080 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 -0.91 =B1 0.02, the high energy photon index beta =3D -2.42 =B1 0.07, the peak energy Ep =3D 394 =B1 11 keV, chi2 =3D 90/92 dof.
The spectrum near the maximum count rate (measured from T0+139.264 s to T0+143.872 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 -0.65 =B1 0.03, the high energy photon index beta =3D -2.22 =B1 0.05, the peak energy Ep =3D 390 =B1 16 keV, chi2 =3D 111/96 dof.
Assuming the NOT redshift z=3D1.238 (de Ugarte Postigo, et al., GCN 15187= ), 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 of GRB 130907A: the isotropic energy release E_iso is (3.3 =B1 0.1)x10^54 erg, the peak luminosity L_iso is (2.0 =B1 0.1)x10^53 erg/s, and the rest-frame peak energy Ep,i =3D (880 =B1 25) keV
All the quoted results are preliminary.
GCN Circular #15204
V. Savchenko, V. Beckmann (APC), C. Ferrigno, E. Bozzo, M. Beck (ISDC), J. Borkowski (CAMK/Torun), D. G=F6tz (CEA/Saclay), S. Mereghetti (INAF/IASF-Milano), A. von Kienlin, A. Rau (MPE), and K. Hurley (SSL/Berkeley)
GRB 130907A, detected by Swift/BAT (Palmer et al. GCN 15183), Fermi/LAT (Vianello et al. GCN 15196) and Konus-Wind (Frederiks et al, GCN 15203), has been independently detected by the SPI Anti-Coincidence System (ACS) on-board INTEGRAL. The SPI-ACS light curve reveals the rich multi-peak structure of this burst starting at 2013-09-07T21:39:16. Several bright peak s are followed by a major activity episode at about T0+100s. The maximum count-rate of 94,000 counts/sec (approximately corresponding to 1e-5 erg/cm2/s in the 75 keV-1 MeV range, Vigano and Mereghetti 2009) over the time bin length of 50 msec is reached at T0+115s. The total duration of this GRB is about 250 seconds.
The SPI-ACS light curve of this GRB is available at: http://www.isdc.unige.ch/integral/ibas/cgi-bin/ibas_acs_web.cgi/?trigger 2013-09-07T21-39-16.00-00000-00000-0
All SPI-ACS light curves are available (both as images and data files) at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi. The light curves, binned at 50 ms, are derived from 91 independent detect ors with different lower energy thresholds (mainly between 50 keV and 150 keV). SPI-ACS has no upper energy threshold and can detect photons with energies up to at least 100 MeV. The ACS response varies as a function of the GRB incident angle. For these reasons we caution that the count rates cannot be easily translated into physical flux units.
GCN Circular #15205
H. A. Krimm (GSFC/USRA), J. R. Cummings (GSFC/UMBC), D. M. Palmer (LANL), C. B. Markwardt (GSFC) for the Swift-BAT team):
Using the complete data set from T-239 to T+963 sec, we report further analysis of BAT GRB 130907A (trigger #569992) (Page, et al., GCN Circ. 15183). The initial report on the BAT data was presented in Cummings, et al., GCN Circ. 15202.
The burst started while Swift was slewing from another target, and the burst location came into the BAT coded field of view at about T-80 seconds. The initial pair of peaks at T-117 that triggered Konus-Wind (Golenetskii, et al., GCN Circ. 15203) and INTEGRAL/SPI-ACS (Savchenko, et al., GCN Circ. 15204) were seen from outside the coded field in the non-weighted rates.
The mask-weighted light curve is described in Cummings, et al., GCN Circ. 15202. Although there are no discrete peaks later than T+240 seconds, the burst is still detected in the mask-weighted rate out to T+963 sec, when this data cuts off and continues to be detected onboard in a 64-second image starting at T+1388, and possibly later. Since the BAT event data does not cover the full extent of the burst, we cannot reliably calculate T90 at this point, but it is at least 360 seconds.
The time-averaged spectrum from T-73.7 to T+767.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.17 +- 0.02. The fluence in the 15-150 keV band is 1.4 +- 0.01 x 10^-4 erg/cm2. We note that this time interval does not cover the entire burst duration, so should be considered a lower limit.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/569992/BA/
GCN Circular #15207
A.J. van der Horst (University of Amsterdam) reports on behalf of a large collaboration:
"We observed the position of the GRB 130907A afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope at September 9 09.99 UT to 20.69 UT, i.e. 1.51 - 1.96 days after the burst (GCN 15183). We detect a radio source with a flux density of 0.19 +/- 0.03 mJy at the position of the optical counterpart (GCN 15187).
We would like to thank the WSRT staff for quickly scheduling and obtaining these observations."
GCN Circular #15208
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB)= , J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC)= , Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UN= AM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley= (GSFC) report:
We observed the field of GRB 130907A (Page et al., GCN 15183) 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 2013/09 10.12 to 2013/09 10.16 UTC (53.18 = to 54.12 hours after the BAT trigger), obtaining a total of 0.71 hours exposure in the r and i bands and 0.30 hours exposure in the Z, Y, J, and= H bands.
For the source reported in Lee et al. (GCN 15192), in comparison with SDS= S DR9 and 2MASS, we obtain the following detections and upper limits (3-sigma):
```
  r   21.92 +/- 0.12
  i   21.38 +/- 0.09
  Z   > 21.37
  Y   > 20.87
  J   > 20.58
  H   > 19.97
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source has faded by about tw= o magnitudes in all bands since our measurements two nights ago (Lee et al.= , GCN 15192). We note that the source intensity in the r and i bands is no= w comparable to the cataloged values for the spatially coincident galaxy SD= SS J142333.95+453626.2.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr= o M=E1rtir.
GCN Circular #15209
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), Willia= m H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB)= , J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC)= , Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UN= AM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley= (GSFC) report:
We observed the field of GRB 130907A (Page et al., GCN 15183) 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 2013/09 11.12 to 2013/09 11.16 UTC (77.18 = to 78.08 hours after the BAT trigger), obtaining a total of 0.71 hours exposure in the r and i bands and 0.30 hours exposure in the Z and Y.
For the source reported in Lee et al. (GCN 15192), in comparison with SDS= S DR9 and 2MASS, we obtain the following detections and upper limits (3-sigma):
```
  r     22.40 +/- 0.14
  i     21.73 +/- 0.10
  Z     > 21.80
  Y     > 21.05
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source has faded by about 0.= 4 mags in the r and i bands relative to our observations last night (Butler et al., GCN 15208).
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedr= o M=E1rtir.
GCN Circular #15211
G.E. Anderson, R.P. Fender, T.D. Staley (University of Southampton), A.J. van der Horst and B.A. Rowlinson (University of Amsterdam) report on behalf of a large collaboration:
"We observed the position of the GRB 130907A afterglow at 15 GHz with the Arcminute Microkelvin Imager at September 8 09.90 UT to 11.90 UT, i.e. 12.2 - 14.2 hours after the burst (GCN 15183). We detect a radio source at the position of the optical counterpart (GCN 15187) with a flux density of 1.06 +/- 0.11 mJy.
These observations were triggered via the system described in Staley et. al (2013, MNRAS, 428, 3114). Further follow-up observations are planned."
GCN Circular #15220
E. Gorbovskoy, V. Lipunov, D.Denisenko, V.Kornilov, A.Belinski, N.Tyurina, D.Kuvshinov, N.Shatskiy, P.Balanutsa, A.Kuznetsov, V.V.Chazov, A.Sankovich, D.Zimnukhov Sternberg Astronomical Institute, Moscow State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka
Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB130907A 18 sec after notice time and 43 sec after GRB time at 2013-09-07 21:42:00 UT in two polarizations. The observations were performed at low elevation (zenith angle 84 deg)and under the changing transparency conditions. The OT (Page et. al. GCN15183) appears on the 4th image in the series and is visible on four consecutive images (20, 30, 40 and 50 sec exposures) in both tubes with the signal-to-noise ratio from 3 to 6. Starting with T0+5 min, the image quality was further deteriorating with the OT visible only on the sum of two pairs of synchronous images.
Our photometry results are presented in Table 1.
```
Table 1.
-------
Start date and time     exptime   T_start-T_trig   T_mid-T_trig  P| mag.   err_P      P- mag    err_P-    P| + P-    err. (P| + P-)
-----------------------+--------+----------------+--------------+--------+---------+----------+---------+----------+---------------
2013-09-07 21:42:00.31    10        47               52           <10.5      ---       <10.5      ---      <11.0        ---
2013-09-07 21:42:22.79    10        69               74           <10.5      ---       <10.5      ---      <11.0        ---
2013-09-07 21:42:43.59    20        91               101          <11.0      ---       <11.0      ---      <11.5        ---
2013-09-07 21:43:16.66    20        123              133           12.2      0.2        13.0      0.3       12.5        0.2
2013-09-07 21:43:47.44    30        154              169           13.3      0.4        13.6      0.6       13.5        0.4
2013-09-07 21:44:29.95    40        197              217           13.7      0.5        13.7      0.6       13.9        0.5
2013-09-07 21:45:21.88    50        249              274           13.7      0.5        14.4      0.8       14.0        0.6
2013-09-07 21:46:23.87    60+80     311              387          <13.8      ---       <13.7      ---       13.9        0.6
```
*) All time intervals in seconds. P| and P- is an unfiltered magnitude with RA and DEC orientated polaroid correspondingly. The sign '<' before magnitude means the value is upper limit.
The light curve and movie available here http://master.sai.msu.ru/static/GRB/GRB130907A/grb130907A.html
The epoch of our observations completely covers Swift BAT weak, soft peak from T+210 sec to T+240 sec (Cummings et. al. GCN15202).
Our first automatic and not so exact (due to difficult observing conditions) estimation of the OT magnitude, given in the previous telegram (Gorbovskoy et. al GCN15184), belongs to epoch of the 5th exposure with t_mid=217 sec. after the trigger. This fact isn't clear from the telegram text that could mislead some researchers. We apologize for this inaccuracy.
The message may be cited.
GCN Circular #15223
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 (UCSC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC) , Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 130907A (Page et al., GCN 15183) 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 2013/09 13.13 to 2013/09 13.16 UTC (125.49 to 126.24 hours after the BAT trigger), obtaining a total of 0.36 hours exposure in the r and i bands and 0.15 hours exposure in the Z, Y, J, and H bands.
For the source reported in Lee et al. (GCN 15192), in comparison with SDSS DR9 and 2MASS, we obtain the following upper limits (3-sigma) in the AB magnitude system (not corrected for Galactic extinction in the direction of the GRB) :
```
  r     > 22.68
  i     > 22.62
  Z     > 21.30
  Y     > 20.70
  J     > 20.42
  H     > 19.69
```
We conclude from our most constraining limit (i-band), that the source has faded by at least 0.9 mags since our observation 2 nights ago (Butler et al., GCN 15209). These magnitudes are now significantly fainter than the DR9 catalog magnitudes of SDSS galaxy mentioned by Lee et al.
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #15240
A. Pozanenko (IKI), A. Volnova (IKI), B. Hafizov (UBAI), O. Burhonov (UBAI) report on behalf of larger GRB follow-up collaboration:
We observed the field of Swift GRB 130907A (Page et al., GCN 15183) with AZT-22 telescope equipped with SNUCAM of Maidanak observatory starting Sep., 10 (UT) 11:04:47. We obtained 2 frames with exposures of 300 s in R filter. On stacked images we clearly detect the source reported by Lee et al., (GCN 15192). The astrometry of the source is following
```
RA(J2000) 14 23 34.01
Dec(J2000) +45 36 36.6
```
with uncertainty of 0.18 arcsec in both coordinates.
The details of the photometry are following:
```
t_start, filter Exposure, t-t0,      OT
(UT)            sec       mid,days
11:04:47 R      2*300     2.56166    21.44 +/- 0.16
```
The photometry is based on a nearby SDSS-DR9 star J142338.63+453547.2 with R mag = 18.181 +/- 0.013 (transformation by Lupton 2005)
1411.7368 from 27 Nov 14
P�ter Veres et al.: Early-time VLA observations and broad-band afterglow analysis of the Fermi-LAT detected GRB 130907A
We present multi-wavelength observations of the hyper-energetic gamma-ray burst (GRB) 130907A, a Swift-discovered burst with early radio observations starting at $\approx 4$ hr after the $\gamma$-ray trigger. GRB 130907A was also detected by the Fermi/LAT instrument and, at late times, showed a strong spectral evolution in X-rays. We focus on the early-time radio observations, especially at $>10 $ GHz, to attempt identifying reverse shock signatures. While our radio follow-up of GRB 130907A ranks among the earliest observations of a GRB with the Karl G. Jansky Very Large Array (VLA), we did not see a clear signature of a reverse shock. We model the broad-band data using a simple forward-shock synchrotron scenario and require a transition from a wind environment to a constant density interstellar medium (ISM) in order to account for the observed features. We also derive the underlying physical parameters of the fireball, which are within typical ranges except for the wind density parameter ($A_*$), which is higher than those for bursts with wind-ISM transition, but typical for the general population of bursts. We note the importance of early-time radio observations of the afterglow (and of well sampled light curves) to unambiguously identify the potential contribution of the reverse shock.

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