Gamma-ray Burst 111201A
(All information courtesy of the instrument teams.)
Previous IAU Circulars
Results of Observations
- GCN Circular #12608
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Automated BAT ground analysis found a burst that occurred at 14:22:45 UT
with a significance of 10.8 sigma (15-200 keV) from the failed event data
of trigger #508800. The event is temporary coincident with the Fermi GBM
344442167. The best BAT location is RA, Dec = 190.4854, 32.9935 deg, which is
RA(J2000) = 12h 41m 56.5s
Dec(J2000) = +32d 59' 36.6"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
The mask-weighted light curve created from the failed event data
(available from 14:22:41 to 14:22:51 UT) shows an increase in the rate ~1 sec
after the event data start time. The count rate stays constant until the
end of the event data. From the BAT raw light curve, the duration of the
event is ~20 sec long.
The spectrum extracted using the full event data is best fit by a simple
power-law model. The power law index of the spectrum is 1.6 +- 0.3. The
fluence in 15-150 keV band measured from the 10 sec long event data is
4.6 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from
14:22:46 UT is 1.1 +- 0.3 ph/cm2/sec. All the quoted errors are at the
90% confidence level.
Swift ToO observation of this burst has been scheduled.
- GCN Circular #12609
J. A. Kennea (PSU) and T. Sakamoto (GSFC/UMBC) report on behalf of the
We have analysed 3.0 ks of XRT data for the GBM/BAT-detected burst:
GRB111201A (Sakamoto et al. et al. GCN Circ. 12608), from 26.5 ks to
32.7 ks after the GBM/BAT trigger. The data are entirely in Photon
Counting (PC) mode. An X-ray source is detected within the GBM/BAT
error circle. The refined XRT position is RA, Dec = 190.47701,
+32.98791 which is equivalent to:
RA (J2000): 12 41 54.48
Dec(J2000): +32 59 16.5
with an uncertainty of 3.6 arcsec (radius, 90% confidence). This
position is 32 arcsec from the BAT position.
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.3 (+/-0.4). The
best-fitting absorption column is 3.6 (+1.7, -1.4) x 10^21 cm^-2, in
excess of the Galactic value of 1.3 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 (7.3 x 10^-11) erg
A summary of the PC-mode spectrum is thus:
Total column: 3.6 (+1.7, -1.4) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^20 cm^-2
Excess significance: 4.1 sigma
Photon index: 2.3 (+/-0.4)
The results of the XRT-team automatic analysis are available at
This circular is an official product of the Swift-XRT team.
- GCN Circular #12610
N.P.M. Kuin (MSSL/UCL) and T. Sakamoto (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 111201A
26513 s after the BAT trigger (Sakamoto et al., GCN Circ. 12608).
No optical afterglow consistent with the XRT position (Kennea and
Sakamoto, GCN Circ. 12609) 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 initial
Filter T_start(s) T_stop(s) Exp(s) Mag
white 26513 32667 2746 >22.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998)
- GCN Circular #12611
K.L. Page (U. Leicester) and T. Sakamoto (GSFC/UMBC) report on behalf of
the Swift-XRT team:
Swift performed a second follow-up observation of the GBM/BAT-detected
burst, GRB 111201A (Sakamoto et al., GCN Circ. 12608; Kennea & Sakamoto,
GCN Circ. 12609), collecting a further 3 ks of data between 92.2 and 97.6
ks after the trigger. This additional observation shows the source to be
fading with a power-law decay of alpha = 0.55 (+0.22, -0.20), confirming
it is, indeed, the X-ray afterglow of the burst.
This circular is an official product of the Swift-XRT team.
- GCN Circular #12623
X.-H. Zhao (YNAO), D. Xu (WIS), J.-R. Mao, J.-M. Bai (YNAO) report:
We observed the field of GRB 111201A (Sakamoto et al., GCN 12608) with
the 2.4m Gao-Mei-Gu (GMG) telescope equipped with YFOSC. Observation
were carried out in a very poor seeing of ~3.6" and 6x600s R-band
images were obtained starting at 21:38:32 UT on 2nd Dec. 2011 (i.e.,
31.27hrs after the burst).
We found a faint and apparently extended source on the southern border
of the XRT error circle (Kennea et al., GCN 12609) at coordinates
with a circle error radius of ~4 arcsec. The source had R~22.7 mag,
calibrated with nearby USNO B1 stars.
We thank W.-M. Yi, H.-Y. Gao and F. He for performing these observations.
- GCN Circular #12680
V.V. Golovnya (Main Astro Obs, Kyiv)
We have undertaken the review of the sky area in vicinity of
GRB 111201A (J.A.Kennea (PSU) and T.Sakamoto, GCN Circ.12609)
on astronegatives, collected in Ukrainian NAS Main astronomical
observatory plate archive (1976-1996). All the plates with
the possible object appearance are digitized using Microtek
ScanMaker 9800XL TMA and Epson Expression 10000XL flatbed
scanners and have been placed into Golosiiv Plate Archive
database DBGPA with open access to them.
The list of plates is given in the table:
YYYYMMDD/TimeUT --Plates-- Exp. LimMag Star USNOA2
19870527/224011 GUA040C000022B 18.2 15.85 1200-06937537
19890205/015711 GUA040C001420 18.0 15.85 1200-06937537
19890504/200715 GUA040C001461A 16.0 15.85 1200-06937537
19900223/003254 GUA040C001582 16.0 16.55 1200-06937256
19930425/205928 GUA040C002202 22.5 15.35 1200-06936881
19930430/205716 GUA040C002205A 18.8 15.85 1200-06937537
Plates-the plate's identifier in GUA040C archive
of DWA (D/F=400/2000, M=103"/mm) of the Ukrainian NAS
Main Astro obs in Kyiv (Marsden's number - 83).
Exp. - Duration of the maximum exposure (minutes).
LimMag - Limited V mag, derived in the 18 minutes area around
the location given in GCN Circ.12609:
RA(J2000): 12h 41m 54.48s, Dec(J2000): +32d 59' 16.5"
Star USNOA2 - Comparison star.
The preview images of 6 areas together with
the 17x19 min.of arc area from SkyMap can be found in
The images with full resolution are available via e-mail on
1.L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0),
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Jochen Greiner, last update: 14-Dec-2011