Gamma-ray Burst 130716A
(All information courtesy of the instrument teams.)
Previous IAU Circulars
Results of Observations
- GCN Circular #15006
During a TDRSS-275 outage between 10:25 and 10:59 UT this morning, Swift-BAT
triggered on GRB 130716A (trigger #561974). Due to the TDRSS outage, prompt
data was not available. Data has now been received. The burst occurred at
The BAT refined position is RA, Dec179.581,63.057, which is:
RA (J2000) 11h 58m 19.4s
Dec (J2000) 63d 03' 25"
with an estimated uncertainty radius of 2.5 arcmin (90% confidence). The
partial coding was 63%.
The BAT lightcurve shows a double overlapping peak, the first peak smaller,
with a total duration of about 0.8 seconds.
The XRT began observing the field at 10:38:55 UT, 122 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 179.5770, 63.0529 which is equivalent to:
RA(J2000) = +11h 58m 18.5s
Dec(J2000) = +63d 03' 10.6"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 15.7 arcseconds from the BAT onboard position, within the BAT
UVOT data is not yet available.
Burst Advocate for this burst is Stefan Immler (stefan.immler AT nasa.gov).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information:http://www.swift.psu.edu/too.html.)
- GCN Circular #15007
M. H. Siegel (PSU) and S. Immler (GSFC) report on behalf of the
The Swift/UVOT began settled observations of the field of GRB 130716A
120s after the BAT trigger (Cummings et al., GCN Circ. 15006). No
optical afterglow consistent with the XRT position is detected in
the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 120 270 147 >20.47
white 888 1038 147 >20.90
v 5858 6057 196 >19.17
b 5242 5442 196 >20.01
u (fc) 334 583 245 >19.86
uvw1 4832 5032 196 >19.61
uvm2 4627 4827 196 >19.64
uvw2 5653 5853 196 >20.05
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 #15008
W. Fong, E. Berger and R. Chornock (Harvard) report:
"We observed the field of the short-duration GRB 130716A (Cummings et al.,
GCN 15006) with the Gemini Multi-Object Spectrograph mounted on the Gemini
North 8-m telescope starting on Jul 17.253 UT (19.45 hr after the burst).
We obtained ~15 min of r-band observations in 1" seeing. Calibrated to
stars in the SDSS DR9 catalog, we do not detect any optical source within
the reported XRT position to a 5-sigma limit of r>24.5 mag.
We thank the Gemini staff for their assistance with these observations."
- GCN Circular #15010
J. Norris (BSU), S. D. Barthelmy (GSFC), T. Sakamoto (AGU), N. Gehrels (GSFC)
We report the spectral lag analysis for GRB 130716A (GCN Circ. 15506) based on
the BAT data. Using 16-ms binned light curve, the spectral lag for the 25-50 keV
to 100-350 keV bands is -2 (+50/-40) ms, and +11 (+25/-14) ms for the 15-25 keV to
50-100 keV bands. Although the lag value is not well constrained (relatively large
errors), we believe this burst is more consistent with short burst category. There is
no evidence for extended emission.
- GCN Circular #15011
S. Foley (UCD) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 10:36:53.59 UT on 16 July 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 130716A (trigger 395663816 / 130716442)
which was also detected by the Swift/BAT
(Cummings et al. 2013, GCN 15006).
The GBM on-ground location is consistent with the Swift position.
The GBM light curve consists of two overlapping pulses
with a duration (T90) of about 0.8 s (50-300 keV).
The time-averaged spectrum from T0-0.256 s to T0+0.576 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.23 (+0.28/-0.24) and
the cutoff energy, parameterized as Epeak, is 635 (+184/-112) keV.
The event fluence (10-1000 keV) in this time interval is
(9.2 +/- 0.7)E-07 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+0.256 s in the 10-1000 keV band
is 6.2 +/- 0.9 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
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Jochen Greiner, last update: 19-Jul-2013