Gamma-ray Burst 130806A

(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:     Tue 06 Aug 13 02:51:54 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     565562,   Seg_Num: 0
GRB_RA:           35.872d {+02h 23m 29s} (J2000),
                  36.154d {+02h 24m 37s} (current),
                  34.844d {+02h 19m 23s} (1950)
GRB_DEC:         +67.530d {+67d 31' 48"} (J2000),
                 +67.591d {+67d 35' 28"} (current),
                 +67.303d {+67d 18' 10"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       5385 [cnts]    Image_Peak=454 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   137     E_range: 15-50 keV
BKG_INTEN:       28537 [cnts]
BKG_TIME:        10277.12 SOD {02:51:17.12} UT
BKG_DUR:         8 [sec]
GRB_DATE:        16510 TJD;   218 DOY;   13/08/06
GRB_TIME:        10293.95 SOD {02:51:33.95} UT
GRB_PHI:         -70.09 [deg]
GRB_THETA:        12.37 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     27.03 [sigma]
IMAGE_SIGNIF:    14.81 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +1  +3  +0  +1 -19  +0 
SUN_POSTN:       136.29d {+09h 05m 10s}  +16.68d {+16d 40' 35"}
SUN_DIST:         78.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.21d {+08h 24m 50s}  +14.22d {+14d 13' 07"}
MOON_DIST:        76.90 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.58,  6.22 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       61.61, 49.35 [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 = 69.93,-3.35 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Aug 13 02:52:51 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10360.20 SOD {02:52:40.20} UT,   66.2 [sec] since BAT Trigger Time
COUNTS:          2    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Aug 13 02:55:13 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     565562,   Seg_Num: 0
GRB_RA:           35.872d {+02h 23m 29s} (J2000),
                  36.154d {+02h 24m 37s} (current),
                  34.844d {+02h 19m 23s} (1950)
GRB_DEC:         +67.530d {+67d 31' 48"} (J2000),
                 +67.591d {+67d 35' 28"} (current),
                 +67.303d {+67d 18' 10"} (1950)
GRB_DATE:        16510 TJD;   218 DOY;   13/08/06
GRB_TIME:        10293.95 SOD {02:51:33.95} UT
TRIGGER_INDEX:   137
GRB_PHI:         -70.09 [deg]
GRB_THETA:        12.37 [deg]
DELTA_TIME:      77.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     27.03 [sigma]
IMAGE_SIGNIF:    14.81 [sigma]
LC_URL:          sw00565562000msb.lc
SUN_POSTN:       136.29d {+09h 05m 10s}  +16.68d {+16d 40' 32"}
SUN_DIST:         78.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.24d {+08h 24m 57s}  +14.21d {+14d 12' 42"}
MOON_DIST:        76.91 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.58,  6.22 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       61.61, 49.35 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 69.93,-3.35 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Aug 13 02:57:31 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
POINT_ROLL:      73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10362.71 SOD {02:52:42.71} UT,   68.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.617
N_STARS:         48
X_OFFSET:        593 [pixels]
Y_OFFSET:        511 [pixels]
X_MAX:           1552 [pixels]
Y_MAX:           1470 [pixels]
DET_THRESH:      22
PHOTO_THRESH:    13
SL_URL:          sw00565562000msufc0068.fits
SUN_POSTN:       136.29d {+09h 05m 11s}  +16.68d {+16d 40' 31"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.26d {+08h 25m 02s}  +14.21d {+14d 12' 25"}
MOON_DIST:        76.94 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Aug 13 02:57:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
POINT_ROLL:      73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10362.71 SOD {02:52:42.71} UT,   68.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        6.617
N_STARS:         48
X_OFFSET:        593 [pixels]
Y_OFFSET:        511 [pixels]
X_MAX:           1552 [pixels]
Y_MAX:           1470 [pixels]
DET_THRESH:      22
PHOTO_THRESH:    13
SL_URL:          sw00565562000msufc0068.fits
SUN_POSTN:       136.29d {+09h 05m 11s}  +16.68d {+16d 40' 30"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.26d {+08h 25m 03s}  +14.21d {+14d 12' 21"}
MOON_DIST:        76.94 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [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:     Tue 06 Aug 13 02:59:01 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
ROLL:            73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10362.71 SOD {02:52:42.71} UT,   68.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     397450373
X_OFFSET:        912 [pixels]
Y_OFFSET:        830 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1072
Y_GRB_POS:       990
BINNING_INDEX:   1
IM_URL:          sw00565562000msuni0079.fits
SUN_POSTN:       136.29d {+09h 05m 11s}  +16.67d {+16d 40' 30"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.27d {+08h 25m 05s}  +14.20d {+14d 12' 13"}
MOON_DIST:        76.95 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [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:     Tue 06 Aug 13 02:59:25 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
ROLL:            73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10362.71 SOD {02:52:42.71} UT,   68.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     397450373
X_OFFSET:        912 [pixels]
Y_OFFSET:        830 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1072
Y_GRB_POS:       990
BINNING_INDEX:   1
IM_URL:          sw00565562000msuni0079.fits
SUN_POSTN:       136.30d {+09h 05m 11s}  +16.67d {+16d 40' 29"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.27d {+08h 25m 06s}  +14.20d {+14d 12' 10"}
MOON_DIST:        76.95 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [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 NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Aug 13 03:03:12 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
POINT_ROLL:      73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10575.14 SOD {02:56:15.14} UT,   281.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.354
N_STARS:         10
X_OFFSET:        353 [pixels]
Y_OFFSET:        271 [pixels]
X_MAX:           1792 [pixels]
Y_MAX:           1710 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw00565562000msufc0281.fits
SUN_POSTN:       136.30d {+09h 05m 11s}  +16.67d {+16d 40' 27"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.31d {+08h 25m 13s}  +14.19d {+14d 11' 42"}
MOON_DIST:        76.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.  
COMMENTS:        The Pointing RA,Dec,Roll values came from the 1st SrcList Notice.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Aug 13 03:03:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
POINT_ROLL:      73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10575.14 SOD {02:56:15.14} UT,   281.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.354
N_STARS:         10
X_OFFSET:        353 [pixels]
Y_OFFSET:        271 [pixels]
X_MAX:           1792 [pixels]
Y_MAX:           1710 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw00565562000msufc0281.fits
SUN_POSTN:       136.30d {+09h 05m 11s}  +16.67d {+16d 40' 27"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.31d {+08h 25m 14s}  +14.19d {+14d 11' 40"}
MOON_DIST:        76.97 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [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:     Tue 06 Aug 13 03:04:36 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
ROLL:            73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10575.14 SOD {02:56:15.14} UT,   281.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     397450586
X_OFFSET:        912 [pixels]
Y_OFFSET:        830 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1072
Y_GRB_POS:       990
BINNING_INDEX:   1
IM_URL:          sw00565562000msuni0292.fits
SUN_POSTN:       136.30d {+09h 05m 12s}  +16.67d {+16d 40' 26"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.32d {+08h 25m 16s}  +14.19d {+14d 11' 31"}
MOON_DIST:        76.98 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The Pointing RA,Dec,Roll values came from the 1st Image Notice.  
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:     Tue 06 Aug 13 03:04:57 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     565562,   Seg_Num: 0
POINT_RA:         35.834d {+02h 23m 20s} (J2000)
POINT_DEC:       +67.528d {+67d 31' 40"} (J2000)
ROLL:            73.982d
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10575.14 SOD {02:56:15.14} UT,   281.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     397450586
X_OFFSET:        912 [pixels]
Y_OFFSET:        830 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1072
Y_GRB_POS:       990
BINNING_INDEX:   1
IM_URL:          sw00565562000msuni0292.fits
SUN_POSTN:       136.30d {+09h 05m 12s}  +16.67d {+16d 40' 26"}
SUN_DIST:         78.42 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.32d {+08h 25m 17s}  +14.19d {+14d 11' 29"}
MOON_DIST:        76.98 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.56,  6.21 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       61.59, 49.36 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #15071
B.P. Gompertz (U Leicester), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC) and C. A. Swenson (PSU) report on behalf of the Swift Team:
At 02:51:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130806A (trigger=565562). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 35.872, +67.530 which is
```
   RA(J2000) = 02h 23m 29s
   Dec(J2000) = +67d 31' 48"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 10 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 02:52:40.2 UT, 66.2 seconds after the BAT trigger. Using promptly downlinked data we find a possible X-ray source located at RA, Dec 35.92827, 67.53242 which is equivalent to:
```
   RA(J2000)  = 02h 23m 42.8s
   Dec(J2000) = 67d 31' 56.7"
```
with an uncertainty of 9.0 arcseconds (radius, 90% containment). This location is 78 arcseconds from the BAT onboard position, within the BAT error circle. We cannot determine whether the source is fading at the present time.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 68 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 1.19.
Burst Advocate for this burst is B.P. Gompertz (bpg6 AT le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 06 Aug 13 03:26:19 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     565562,   Seg_Num: 0
GRB_RA:           35.9283d {+02h 23m 42.79s} (J2000),
                  36.2104d {+02h 24m 50.49s} (current),
                  34.8999d {+02h 19m 35.97s} (1950)
GRB_DEC:         +67.5323d {+67d 31' 56.2"} (J2000),
                 +67.5935d {+67d 35' 36.5"} (current),
                 +67.3054d {+67d 18' 19.4"} (1950)
GRB_ERROR:       10.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       9.99e-12 [erg/cm2/sec]
GRB_SIGNIF:      4.00 [sigma]
IMG_START_DATE:  16510 TJD;   218 DOY;   13/08/06
IMG_START_TIME:  10360.20 SOD {02:52:40.20} UT,   66.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.61 237.19 261.35 242.66
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       136.31d {+09h 05m 15s}  +16.67d {+16d 40' 11"}
SUN_DIST:         78.40 [deg]   Sun_angle= 6.7 [hr] (West of Sun)
MOON_POSTN:      126.50d {+08h 26m 00s}  +14.15d {+14d 08' 48"}
MOON_DIST:        77.05 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:      131.60,  6.23 [deg] galactic lon,lat of the burst
ECL_COORDS:       61.64, 49.34 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values are not valid.

GCN Circular #15072
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 1580 s of XRT Photon Counting mode data and 4 UVOT images for GRB 130806A, 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 = 35.92894, +67.53196 which is equivalent to:
```
RA (J2000): 02h 23m 42.95s
Dec (J2000): +67d 31' 55.1"
```
with an uncertainty of 2.2 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 #15076
A. Y. Lien (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC= /UMBC), N. Gehrels (GSFC), B.P. Gompertz (U Leicester), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130806A (trigger #565562) (Gompertz, et al., GCN Circ. 15071). The BAT ground-calculated position is RA, Dec =3D 35.907, 67.525 deg which is
```
     RA(J2000)  =3D  02h 23m 37.7s
     Dec(J2000) =3D +67d 31' 30.5"
```
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 95%.
The mask-weighted light curves shows a faint initial 2-sec long peak starting at T-5 sec, followed by the main peak from T-1 to T+2 sec. T90 (15-350 keV) is 6.1 +- 0.5 sec (estimated error including systematics).
The time-averaged spectrum from T-4.5 to T+2.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.50 +- 0.22. The fluence in the 15-150 keV band is 1.7 +- 0.2 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+0.32 sec in the 15-150 keV band is 1.3 +- 0.1 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/565562/BA/
We note that the fluence ratio in a simple power-law fit between the 25-50 keV band and the 50-100 keV band is 1.41. This fluence ratio is larger than 1.32 which can be achieved in the Band function of alpha=3D-1.0, beta=3D-2.5, and Epeak=3D30 keV. Thus, preliminary analysis shows that Epeak of the burst is very likely around or below 30 keV. Therefore the burst can be classified as an X-ray flash (e.g. Sakamoto et al. 2008, ApJ, 679, 570). A fit to a Band model gives nearly the same reduced chi-squared as a simple power=3Dlaw fit. The Band fit gives Epeak =3D 18.9 (+3.2, -5.8) and beta =3D -2.6 =B1 0.3. The alpha parameter is not constrained by the fit.
GCN Circular #15077
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME collaboration:
We observed the field of GRB 130806A (Gompertz et al., GCNC 15071) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2013-08-06 12:29:43 UT (~9.6 h after the burst). We did not find any new point source within the enhanced XRT error circle (Beardmore et al., GCNC 15072) in all the three bands.
Three sigma upper limits of the OT are listed below. We used GSC 2.3 catalog for flux calibration.
```
#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.54100    15:50:36    4020.0   >19.4  >19.5  >18.7
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
```
GCN Circular #15078
K.L. Page (U. Leicester) and B.P. Gompertz (U Leicester) report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 130806A (Gompertz et al. GCN Circ. 15071), from 77 s to 57.9 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 15072).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.57 (+0.08, -0.09).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.6 (+0.6, -0.5). The best-fitting absorption column is 6.8 (+4.7, -2.9) x 10^21 cm^-2, consistent with the Galactic value of 3.9 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 6.1 x 10^-11 (9.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.8 (+4.7, -2.9) x 10^21 cm^-2
Galactic foreground: 3.9 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.6 (+0.6, -0.5)
```
If the light curve continues to decay with a power-law decay index of 0.57, the count rate at T+24 hours will be 2.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-13 (2.5 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00565562.
This circular is an official product of the Swift-XRT team.
GCN Circular #15079
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 130806A (B.P. Gompertz et al., GCNC 15071) 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 2013-08-06 14:11:23 UT ( ~11.3 h afterthe burst). And we could not find any new point source within the XRT error circle (A.P. Beardmore et al., GCNC 15072) in all the three bands.
The results of photometry (3 sigma upper limits) are listed below. We used GSC2.3 catalog for flux calibration.
```
T0+[hour]      MID-UT        T-EXP[sec]           g'                Rc                Ic
----------------------------------------------------------------------------------------------------
   ~15.0         17:50:01          5580               >21.3         >20.4           >19.7
----------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst [hour]
T-EXP: Total Exposure time [sec]
```
GCN Circular #15084
S. T. Holland (STScI) and B. P. Gompertz (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 130806A starting 69 s after the BAT trigger (Gompertz et al. 2013, GCNC 15071). We do not detect any new source consistent with the UVOT-enhanced XRT position (Beardmore et al. 2013, GCNC 15072) in any of the UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the finding chart (FC) exposures and initial summed exposures are presented below.
```
-------------------------------------------------
Filter      TSTART      TSTOP   Exposure      Mag
-------------------------------------------------
white (FC)      69        218        147    >20.6
   u (FC)     282        305         23    >18.2
-------------------------------------------------
   b         3571     11,831       1028    >21.3           
   u         4801     11,172       1082    >21.4
   v         4187       5823        393    >19.9
uvw1         4597     10,259       1116    >21.2
uvm2         4391     15,843       1066    >20.9
uvw2         3982       5618        393    >20.7
white         3776       5411        393    >21.8
-------------------------------------------------
```
The quoted upper limits have not been corrected for the expected extinction due to the Galactic reddening along the line of sight to this burst of E(B-V) = 1.02 mag (Schlafly et al. 2011, ApJS, 737, 103). GRB 130806A was 6 degrees above the Galactic Plane, so this extinction value is highly uncertain.

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Jochen Greiner, last update: 08-Aug-2013 [Disclaimer]