Gamma-ray Burst 130727A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 27 Jul 13 16:59:19 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     564342,   Seg_Num: 0
GRB_RA:          330.800d {+22h 03m 12s} (J2000),
                 331.055d {+22h 04m 13s} (current),
                 329.855d {+21h 59m 25s} (1950)
GRB_DEC:         -65.575d {-65d 34' 28"} (J2000),
                 -65.509d {-65d 30' 30"} (current),
                 -65.817d {-65d 48' 59"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       2475 [cnts]    Image_Peak=155 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   42     E_range: 25-100 keV
BKG_INTEN:       27786 [cnts]
BKG_TIME:        60309.15 SOD {16:45:09.15} UT
BKG_DUR:         8 [sec]
GRB_DATE:        16500 TJD;   208 DOY;   13/07/27
GRB_TIME:        60319.52 SOD {16:45:19.52} UT
GRB_PHI:          10.03 [deg]
GRB_THETA:        38.84 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     15.03 [sigma]
IMAGE_SIGNIF:    8.90 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  -1  +0  +0 +65  +0 
SUN_POSTN:       127.16d {+08h 28m 39s}  +19.06d {+19d 03' 30"}
SUN_DIST:        130.95 [deg]   Sun_angle= 10.4 [hr] (West of Sun)
MOON_POSTN:        8.98d {+00h 35m 56s}   +6.86d {+06d 51' 22"}
MOON_DIST:        77.52 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      325.38,-43.50 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      303.41,-49.04 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session.  
COMMENTS:        This is 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 = 176.75,19.26 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the INTEGRAL_SPIACS event (trignum=6914).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 27 Jul 13 16:45:45 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     396636323
GRB_RA:          321.383d {+21h 25m 32s} (J2000),
                 321.659d {+21h 26m 38s} (current),
                 320.361d {+21h 21m 27s} (1950)
GRB_DEC:         -65.183d {-65d 10' 59"} (J2000),
                 -65.124d {-65d 07' 26"} (current),
                 -65.399d {-65d 23' 56"} (1950)
GRB_ERROR:       7.87 [deg radius, statistical plus systematic]
GRB_INTEN:       302 [cnts/sec]
DATA_SIGNIF:     14.10 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        16500 TJD;   208 DOY;   13/07/27
GRB_TIME:        60320.91 SOD {16:45:20.91} UT
GRB_PHI:         194.00 [deg]
GRB_THETA:       135.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.86
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 0,0,1, 0,0,1, 0,0,
SUN_POSTN:       127.15d {+08h 28m 37s}  +19.06d {+19d 03' 38"}
SUN_DIST:        132.94 [deg]   Sun_angle= 11.0 [hr] (West of Sun)
MOON_POSTN:        8.86d {+00h 35m 27s}   +6.82d {+06d 48' 56"}
MOON_DIST:        79.86 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      328.43,-40.28 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      298.60,-46.77 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 153.80,22.50 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 27 Jul 13 16:45:54 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      57
TRIGGER_NUM:     396636323
GRB_RA:          334.417d {+22h 17m 40s} (J2000),
                 334.660d {+22h 18m 38s} (current),
                 333.514d {+22h 14m 03s} (1950)
GRB_DEC:         -64.850d {-64d 50' 59"} (J2000),
                 -64.782d {-64d 46' 53"} (current),
                 -65.100d {-65d 06' 00"} (1950)
GRB_ERROR:       7.43 [deg radius, statistical plus systematic]
GRB_INTEN:       305 [cnts/sec]
DATA_SIGNIF:     20.40 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        16500 TJD;   208 DOY;   13/07/27
GRB_TIME:        60320.91 SOD {16:45:20.91} UT
GRB_PHI:         202.00 [deg]
GRB_THETA:       135.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.27
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,0,1, 0,0,1, 0,0,
SUN_POSTN:       127.16d {+08h 28m 37s}  +19.06d {+19d 03' 38"}
SUN_DIST:        130.74 [deg]   Sun_angle= 10.2 [hr] (West of Sun)
MOON_POSTN:        8.87d {+00h 35m 28s}   +6.82d {+06d 48' 58"}
MOON_DIST:        75.97 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      324.94,-45.15 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      305.96,-49.24 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 153.80,22.50 [deg].

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 27 Jul 13 16:45:59 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      56
TRIGGER_NUM:     396636323
GRB_RA:          318.540d {+21h 14m 10s} (J2000),
                 318.794d {+21h 15m 11s} (current),
                 317.599d {+21h 10m 24s} (1950)
GRB_DEC:         -58.100d {-58d 06' 00"} (J2000),
                 -58.043d {-58d 02' 35"} (current),
                 -58.307d {-58d 18' 25"} (1950)
GRB_ERROR:       4.68 [deg radius, statistical only]
DATA_SIGNIF:     22.20 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        16500 TJD;   208 DOY;   13/07/27
GRB_TIME:        60320.91 SOD {16:45:20.91} UT
GRB_PHI:         192.00 [deg]
GRB_THETA:       128.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4143 (Gnd S/W Version number)
SUN_POSTN:       127.16d {+08h 28m 37s}  +19.06d {+19d 03' 38"}
SUN_DIST:        140.09 [deg]   Sun_angle= 11.2 [hr] (West of Sun)
MOON_POSTN:        8.87d {+00h 35m 28s}   +6.82d {+06d 48' 59"}
MOON_DIST:        76.31 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      337.84,-41.41 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      301.01,-39.77 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 27 Jul 13 16:46:05 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      67
TRIGGER_NUM:     396636323
GRB_RA:          325.840d {+21h 43m 22s} (J2000),
                 326.082d {+21h 44m 20s} (current),
                 324.945d {+21h 39m 47s} (1950)
GRB_DEC:         -58.060d {-58d 03' 35"} (J2000),
                 -57.997d {-57d 59' 50"} (current),
                 -58.289d {-58d 17' 20"} (1950)
GRB_ERROR:       3.39 [deg radius, statistical only]
DATA_SIGNIF:     25.60 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        16500 TJD;   208 DOY;   13/07/27
GRB_TIME:        60320.91 SOD {16:45:20.91} UT
GRB_PHI:         197.00 [deg]
GRB_THETA:       128.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4143 (Gnd S/W Version number)
SUN_POSTN:       127.16d {+08h 28m 37s}  +19.06d {+19d 03' 38"}
SUN_DIST:        138.66 [deg]   Sun_angle= 10.7 [hr] (West of Sun)
MOON_POSTN:        8.87d {+00h 35m 28s}   +6.82d {+06d 48' 60"}
MOON_DIST:        73.41 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      336.16,-45.07 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      305.66,-41.33 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.

GCN Circular #15046
M. C. Stroh (PSU), N. Gehrels (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of the Swift Team:
At 16:45:19.52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130727A (trigger=564342). Swift could not slew to the burst due to an Earth limb constraint. The BAT on-board calculated location is RA, Dec 330.800, -65.575 which is
```
  RA(J2000) = 22h 03m 12s
  Dec(J2000) = -65d 34' 28"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). BAT light curve data are currently unavailable.
Due to an observing constraint, Swift will not slew until T0+49.6 minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is M. C. Stroh (stroh AT astroh.org). 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 27 Jul 13 17:56:35 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     564342,   Seg_Num: 0
POINT_RA:        330.776d {+22h 03m 06s} (J2000)
POINT_DEC:       -65.573d {-65d 34' 23"} (J2000)
POINT_ROLL:      149.919d
IMG_START_DATE:  16500 TJD;   208 DOY;   13/07/27
IMG_START_TIME:  63814.17 SOD {17:43:34.17} UT,   3494.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.571
N_STARS:         54
X_OFFSET:        487 [pixels]
Y_OFFSET:        482 [pixels]
X_MAX:           1446 [pixels]
Y_MAX:           1441 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00564342000msufc3494.fits
SUN_POSTN:       127.20d {+08h 28m 49s}  +19.05d {+19d 02' 57"}
SUN_DIST:        130.96 [deg]   Sun_angle= 10.4 [hr] (West of Sun)
MOON_POSTN:        9.48d {+00h 37m 56s}   +7.03d {+07d 01' 37"}
MOON_DIST:        77.83 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      325.39,-43.50 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      303.40,-49.03 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 27 Jul 13 17:57:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     564342,   Seg_Num: 0
POINT_RA:        330.776d {+22h 03m 06s} (J2000)
POINT_DEC:       -65.573d {-65d 34' 23"} (J2000)
POINT_ROLL:      149.919d
IMG_START_DATE:  16500 TJD;   208 DOY;   13/07/27
IMG_START_TIME:  63814.17 SOD {17:43:34.17} UT,   3494.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.571
N_STARS:         54
X_OFFSET:        487 [pixels]
Y_OFFSET:        482 [pixels]
X_MAX:           1446 [pixels]
Y_MAX:           1441 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw00564342000msufc3494.fits
SUN_POSTN:       127.20d {+08h 28m 49s}  +19.05d {+19d 02' 57"}
SUN_DIST:        130.96 [deg]   Sun_angle= 10.4 [hr] (West of Sun)
MOON_POSTN:        9.49d {+00h 37m 57s}   +7.03d {+07d 01' 42"}
MOON_DIST:        77.83 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      325.39,-43.50 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      303.40,-49.03 [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 27 Jul 13 17:57:55 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     564342,   Seg_Num: 0
POINT_RA:        330.776d {+22h 03m 06s} (J2000)
POINT_DEC:       -65.573d {-65d 34' 23"} (J2000)
ROLL:            149.919d
IMG_START_DATE:  16500 TJD;   208 DOY;   13/07/27
IMG_START_TIME:  63814.17 SOD {17:43:34.17} UT,   3494.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     396639825
X_OFFSET:        806 [pixels]
Y_OFFSET:        801 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       966
Y_GRB_POS:       961
BINNING_INDEX:   1
IM_URL:          sw00564342000msuni3505.fits
SUN_POSTN:       127.20d {+08h 28m 49s}  +19.05d {+19d 02' 57"}
SUN_DIST:        130.96 [deg]   Sun_angle= 10.4 [hr] (West of Sun)
MOON_POSTN:        9.50d {+00h 37m 59s}   +7.03d {+07d 01' 52"}
MOON_DIST:        77.83 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      325.39,-43.50 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      303.40,-49.03 [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 27 Jul 13 17:58:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     564342,   Seg_Num: 0
POINT_RA:        330.776d {+22h 03m 06s} (J2000)
POINT_DEC:       -65.573d {-65d 34' 23"} (J2000)
ROLL:            149.919d
IMG_START_DATE:  16500 TJD;   208 DOY;   13/07/27
IMG_START_TIME:  63814.17 SOD {17:43:34.17} UT,   3494.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     396639825
X_OFFSET:        806 [pixels]
Y_OFFSET:        801 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       966
Y_GRB_POS:       961
BINNING_INDEX:   1
IM_URL:          sw00564342000msuni3505.fits
SUN_POSTN:       127.20d {+08h 28m 49s}  +19.05d {+19d 02' 56"}
SUN_DIST:        130.96 [deg]   Sun_angle= 10.4 [hr] (West of Sun)
MOON_POSTN:        9.50d {+00h 38m 00s}   +7.03d {+07d 01' 55"}
MOON_DIST:        77.83 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      325.39,-43.50 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      303.40,-49.03 [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:     Sat 27 Jul 13 17:59:37 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     564342,   Seg_Num: 0
GRB_RA:          330.7993d {+22h 03m 11.83s} (J2000),
                 331.0537d {+22h 04m 12.89s} (current),
                 329.8541d {+21h 59m 24.99s} (1950)
GRB_DEC:         -65.5387d {-65d 32' 19.3"} (J2000),
                 -65.4727d {-65d 28' 21.6"} (current),
                 -65.7806d {-65d 46' 50.1"} (1950)
GRB_ERROR:       2.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  16500 TJD;   208 DOY;   13/07/27
IMG_START_TIME:  63804.00 SOD {17:43:24.00} UT,   3484.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       127.21d {+08h 28m 49s}  +19.05d {+19d 02' 56"}
SUN_DIST:        130.98 [deg]   Sun_angle= 10.4 [hr] (West of Sun)
MOON_POSTN:        9.51d {+00h 38m 03s}   +7.04d {+07d 02' 10"}
MOON_DIST:        77.81 [deg]
MOON_ILLUM:      70 [%]
GAL_COORDS:      325.42,-43.52 [deg] galactic lon,lat of the burst
ECL_COORDS:      303.44,-49.01 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 1.1% < P(seren) < 2.8%.

GCN Circular #15047
M. C. Stroh and M. M. Chester (PSU) report on behalf of the Swift team:
Swift-XRT observed the field of GRB 130727A (Stroh et al., GCN Circ. 15046) starting 3484.5 s after the BAT trigger, due to an observing constraint. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA,Dec = 330.7994, -65.5387 (degrees) which is equivalent to:
```
RA  (J2000.0) = 22 03 11.85
DEC (J2000.0) = -65 32 19.5
```
with an uncertainty of 2.5 arcsec (radius, 90% containment). This location is 130.7 arcseconds from the BAT onboard position, inside the BAT error circle.
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).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 3494 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 none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03.
GCN Circular #15048
M. Perri (ASDC), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU) and G. Cusumano (INAF-IASF PA) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 130727A at 17:43:24.0 UT, 3484.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 330.7988, -65.5384 which is equivalent to:
```
   RA(J2000)  = 22h 03m 11.70s
   Dec(J2000) = -65d 32' 18.4"
```
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 131 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (2.79 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.3 (+1.54/-1.39) x 10^21 cm^-2 (90% confidence).
GCN Circular #15049
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), M. C. Stroh (PSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+831 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130727A (trigger #564342) (Strohe, et al., GCN Circ. 15046). The BAT ground-calculated position is RA, Dec = 330.790, -65.540 deg, which is
```
   RA(J2000)  =  22h 03m 09.5s 
   Dec(J2000) = -65d 32' 23.3" 
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 50%.
The mask-weighted light curve shows several overlapping peaks starting at ~T-5 sec and ening at ~T+30 sec. T90 (15-350 keV) is 13.57 +- 0.81 sec (estimated error including systematics).
The time-averaged spectrum from T-1.08 to T+24.38 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.65 +- 0.05. The fluence in the 15-150 keV band is 3.8 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+7.42 sec in the 15-150 keV band is 7.0 +- 0.3 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/564342/BA/
GCN Circular #15050
C. Guidorzi (U. Ferrara), F. Virgili (LJMU) on behalf of a large collaboration report:
The 2-m Faulkes Telescope South automatically began observing GRB 130727A (Stroh et al. GCN Circ. 15046) on July 27 2013 at 17:01:22 UT (~16 min after the burst trigger).
Within the XRT error circle (Perri et al. GCN Circ. 15048) we find a fading uncatalogued object at coordinates
```
RA(2000.0)=   22:03:11.66
Dec(2000.0)= -65:32:18.7   (error 0.5")
```
with the following magnitudes
```
Mid time from  Total Exp   Filter    Magnitude
trigger (min)   (s)
--------------------------------------------------------------
16.0            10          R       19.3 +- 0.3
47.1           180          R       20.1 +- 0.1
--------------------------------------------------------------
```
Magnitudes are calibrated against nearby USNO-B1 stars.
GCN Circular #15051
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 1995 s of XRT Photon Counting mode data and 5 UVOT images for GRB 130727A, 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 = 330.79842, -65.53856 which is equivalent to:
```
RA (J2000): 22h 03m 11.62s
Dec (J2000): -65d 32' 18.8"
```
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 #15052
V. Sudilovsky, K. Varela, and J. Greiner (all MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 130727A (Swift trigger 564342; Stroh et al., GCN #15046) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile).
Observations started at 23:40 UT on July 27, 2013, 7 hours after the GRB trigger. They were performed at an average seeing of 2.3" and at an average airmass of 2.2.
We detect the afterglow reported by Guidorzi et al. (GCN #15050), and based on images with total exposures of 1500s in g'r'i'z' and 1200s in JHK, we estimate preliminary magnitudes (all in AB) of
```
g' = 22.3 +/- 0.1 mag,
r' = 21.8 +/- 0.1 mag,
i' = 21.6 +/- 0.1 mag,
z' = 21.0 +/- 0.2 mag,
J = 20.4 +/- 0.3 mag,
H > 20.1 mag, and
K > 19.4 mag.
```
Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E(B-V) = 0.03 mag in the direction of the burst (Schlegel et al. 1998).
GCN Circular #15053
A. Goldstein (ORAU/NASA MSFC) reports on behalf of the Fermi GBM Team:
At 16:45:20.91 UT on 27 July 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130727A (trigger 396636323 /130727698) which was also detected by the Swift BAT (Stroh et al. 2013, GCN 15046). The GBM on-ground location is consistent with the Swift position; the angle from the Fermi LAT boresight is 134 degrees.
The GBM light curve consists of one main pulse with substructure with a duration (T90) of about 13.0 s (50-300 keV). The time-averaged spectrum from T0=-1.0 s to T0+12.0 s is adequately fit by a Band function with Epeak = 118 +/- 17 keV, alpha = -1.1 +/- 0.1, and beta = -2.2 +/- 0.1.
The event fluence (10-1000 keV) in this time interval is (8.9 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.1 s in the 8-1000 keV band is 11.1 +/- 0.6 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog.
GCN Circular #15054
M. C. Stroh (PSU) reports on behalf of the Swift-XRT team:
We have analysed 3.9 ks of XRT data for GRB 130727A (Stroh et al. GCN Circ. 15046), from 3.5 ks to 15.8 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 15051).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.89 (+/-0.15).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.01 (+/-0.18). The best-fitting absorption column is 1.6 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 2.8 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.6 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 2.8 x 10^20 cm^-2
Excess significance: 4.6 sigma
Photon index:	     2.01 (+/-0.18)
```
If the light curve continues to decay with a power-law decay index of 0.89, the count rate at T+24 hours will be 0.020 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.4 x 10^-13 (1.0 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/00564342.
This circular is an official product of the Swift-XRT team.
GCN Circular #15055
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 130727A (Swift-BAT trigger 564342: Stroh, et al., GCN 15046) triggered Konus-Wind at T0=3D60324.015 s UT (16:45:24.015)
The light curve shows multiple overlapping peaks from ~T0-2 s to ~T0+12 s. The emission is seen up to ~6 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130727_T60324/
As observed by Konus-Wind, the burst had a fluence of (9.0 =B1 1.1)x10-6 erg/cm2, and a 64-ms peak flux, measured from T0+0.064 s, of (2.9 =B1 0.4)x10-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 18 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha =3D -1.23 =B1 0.22, the high energy photon index beta =3D -2.21 =B1 0.12, the peak energy Ep =3D 113 =B1 22 keV, chi2 =3D 116/97 dof.
All the quoted results are preliminary.
GCN Circular #15056
M. De Pasquale (UCL-MSSL) and M. Stroh (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 130727A 3495 s after the BAT trigger (Stroh et al., GCN Circ. 15046). A source consistent with the XRT position (Goad et al. GCN Circ. 15051) is detected in initial UVOT Finding Chart (FC) exposure taken in white filter, and it is also detected in summed UVOT exposures taken with white and u filters. The same source is marginally detected (confidence level ~2 sigma) in b and uw1 filters.
Its UVOT position (J2000) is
```
RA =3D 22h 03m 11.62s =3D 330.79842
Dec =3D -65d 32m 18.8s =3D -65.53856.
```
with an estimated uncertanties of 0.7 arcseconds. The position of the optical source is consistent with that given by the Faulkes Telescope (Guidorzi et al., GCN 15050).
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_FC          3495         3645          147          21.27 =B1 0.34
white             3495         4876          344          21.35 =B1 0.24
v                 3651        16978          880         >20.96
b                 4471         4671          197          21.44 =B1 0.60
u                 4266        11215          934          20.99 =B1 0.26
w1                4061        10452         1082          21.89 =B1 0.54
m2                3856         5452          355         >20.50
w2                4882        16473         1082         >21.80
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) =3D 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #15058
Martin Topinka, Lorraine Hanlon, Martin Jelinek and Seamus Meehan, on behalf of the Watcher telescope team, report:
We followed the Swift detection of GRB 130727A (Stroh et al., GCN Circ. 15046, Swift trigger 564342) with the Watcher robotic telescope (D=40cm) located at Boyden Observatory, near Bloemfontein in South Africa.
We started imaging the field at 16:59:43 UT on 2013-07-27 (14m 23s after the BAT trigger, 25s after receiving the GCN trigger) taking 60s exposures in the clear filter (C) using an Andor CCD camera.
No optical counterpart is detected within the XRT/UVOT error circle (Goad et al./De Pasquale et al., GCN Circ. 15051/15056) in any of the individual 60s images either in a combined image covering time from 17:01:55 UT to 17:11:40 UT with the total exposure of 540s. Image analysis yields the limiting magnitude of ~18.9 +/- 0.1.
```
Start | End | Exposure | Filter | Limiting mag. | Limiting mag. error
17:01:55 UT | 17:11:40 UT | 540s | C | > 18.9 | 0.1
```
This message is quotable in publications.

Back to JG's homepage

Jochen Greiner, last update: 01-Aug-2013 [Disclaimer]