Gamma-ray Burst 111205A
(All information courtesy of the instrument teams.)
Previous IAU Circulars
Results of Observations
- GCN Circular #12626
K. Hurley, on behalf of the Mars Odyssey and MESSENGER GRB teams,
I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,
S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team, and
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report:
The long-duration, intense GRB 111205A has been observed by
INTEGRAL (SPI-ACS), Konus-Wind, and Mars Odyssey (HEND) so far, at about
47450 s UT (13:10:50).
We have triangulated it to a preliminary, 3 sigma error box whose
RA(2000), deg Dec(2000), deg
134.486 (08h 57m 57s) -31.972 (-31d 58' 20")
134.668 (08h 58m 40s) -32.260 (-32d 15' 37")
134.190 (08h 56m 46s) -31.944 (-31d 56' 38")
134.306 (08h 57m 13s) -31.682 (-31d 40' 57")
134.782 (08h 59m 08s) -31.999 (-31d 59' 57")
The error box area is 492 sq. arcmin, and its maximum
dimension is 39 arcmin.
This box can be improved.
The time history and spectrum will be given in a forthcoming GCN Circular.
A Swift ToO observation has been requested.
- GCN Circular #12627
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The long hard intense GRB 111205A (localized by IPN: Hurley et al., GCN=20
12626) triggered Konus-Wind at T0=3D47450.301 s UT (13:10:50.301)
The light curve starts with a hard bright ~20 s long pulse
followed by a weaker tail of softer emission.
A total duration of the burst is ~85 s.
The emission is seen up to ~8 MeV.
The Konus-Wind light curve of this GRB is available at
As observed by Konus-Wind the burst
had a fluence of (1.7 =B1 0.1)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+1.024 s,
of (2.2 =B1 0.25)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+80.384=20
s) is best fitted in the 20 keV - 10 MeV range
by a power law with exponential cutoff model, for which
alpha =3D -0.82 (-0.04, +0.04),
and Ep =3D 998 (-70, +77) keV,
chi2 =3D 98.0/85 dof.
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.86 (chi2 =3D 97.2/84 dof).
The spectrum at the maximum count rate (measured from T0 to T0+4.352 s)
is best fitted in the 20 keV - 10 MeV range
by a power law with exponential cutoff model, for which
alpha =3D -0.35 (-0.05, +0.05),
and Ep =3D 1120 (-57, +60) keV,
chi2 =3D 68.8/85 dof.
All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.
- GCN Circular #12630
C. A. Wolf (PSU) and E. A. Hoversten (PSU) report on behalf of the
We have analysed 5.0 ks of XRT data for the IPN-detected burst: GRB
(Hurley et al. GCN Circ. 12626), from 198.4 ks to 210.7 ks after the
The data are entirely in Photon Counting (PC) mode. The XRT field-of-
not cover the entire IPN error region. However, an uncataloged X-ray
detected within the observed XRT field which is potentially the
GRB 111205A. The refined XRT position is RA, Dec = 134.6793, -31.94327
which is equivalent to:
RA (J2000): 08 58 43.03
Dec(J2000): -31 56 35.8
with an uncertainty of 4.3 arcsec (radius, 90% confidence). This
position is inside
the IPN error box. We cannot determine at the present time whether the
fading. A follow-up Swift observation is planned in several days to
of the source. The XRT position is outside of the UVOT field of
archival DSS imaging reveals a faint optical source within the XRT
The results of the XRT-team automatic analysis are available at
- GCN Circular #12636
D. A. Kann, A. Rossi, A. Nicuesa Guelbenzu (TLS Tautenburg),
and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of the possible X-ray afterglow (Wolf & Hoversten,
GCN #12630) of the intense IPN GRB 111205A (Hurley et al., GCN #12626,
Golenetskii et al., GCN #12627) simultaneously in g'r'i'z'JHK with GROND
(Greiner et al. 2008, PASP, 120, 405) mounted at the 2.2 m ESO/MPI
telescope at La Silla Observatory (Chile).
Observations were obtained at a
mid-time of 07:35 UT on December 9, 2011, 4.87 days after the GRB trigger,
under excellent conditions. They were performed at an average seeing of
0".7 in the optical bands and at an airmass of 1. The integration time was
1475 sec in g'r'i'z' and 1200 sec in JHK.
The DSS source mentioned by Wolf & Hoversten in the XRT error circle is
detected and is revealed to be a double star separated by about 1".2, both
components clearly resolved due to the excellent seeing. The r'-band
magnitudes of the stars (calibrated against an SDSS standard field) are
16.33 (south-east, edge of error circle) and 16.85 (north-west, in error
circle) with negligible errors.
We therefore posit that this source is not associated with GRB 111205A,
and the X-ray source detected by XRT is not the X-ray afterglow of the
GRB. We note that such a faint X-ray source, at 6E-3 cts/s, would be
untypical for an X-ray afterglow of an intense GRB, even several days
after the GRB.
- GCN Circular #12699
E. A. Hoversten (PSU) and C. A. Wolf (PSU) report on behalf of the
We have analyzed 8.3 ks of XRT data for the IPN detected burst GRB
111205A (Hurley et al. GCN Circ. 12626) from 828 to 853 ks after the
burst. The data are entirely in Photon Counting (PC) mode.
Previously an uncataloged X-ray source was detected by XRT 200 ks
after the burst (Wolf & Hoversten GCN Circ. 12630) which was
identified as the potential afterglow for GRB 111205A, but could not
be confirmed as it was not possible to discern if the source was
fading in a single observation. The follow-up observation reveals
that the source is still detected, but has faded by a factor of 4,
which corresponds to a decay index of 1.0 (+1.3, -0.6) which is
consistent with a GRB late time afterglow. Thus we conclude that the
X-ray source previously reported is the afterglow.
- GCN Circular #12736
L. Elenin (KIAM), A. Volnova (SAI MSU), A. Pozanenko (IKI) report on
behalf of larger GRB follow-up collaboration:
We observed the field of IPN of hard intense GRB 111205A (Hurley et al.,
GCN 12626; Golenetskii et al., GCN 12627) with 0.45-m telescope If ISON-NM
observatory on Dec 8 (09:55:52 - 11:52:34 UT). We took several unfiltered
images of 300 s exposure. All our images cover full IPN error box. On a
stacked image we do not find any new objects within IPN error box in
comparison with DSS. We detect DSS source mentioned by Wolf & Hoversten in
the XRT error circle (Wolf & Hoversten, GCN 12630). However due to bad
seeing we cannot resolve this source into separate sources of a double star
(Kann et al., GCN 12636).
Photometry of the unresolved source based on several nearby USNO-B1.0 stars
(R2 magnitudes) is the following:
t-t0 filter Exp. source uplim (3 sigma)
(mid, days) (s)
2.90513 none 21x300 15.40 +/- 0.05 19.8
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Jochen Greiner, last update: 28-Dec-2011