GRB 111229A
GCN Circular 12783
Subject
GRB 111229A: Swift/UVOT Detection
Date
2011-12-30T13:32:12Z (14 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (MSSL-UCL) and A. Y. Lien (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 111229A
87 s after the BAT trigger (Lien et al., GCN Circ. 12774).
A source consistent with the XRT position (Osborne et al., GCN Circ. 12780) and
the GROND optical position (Nicuesa Guelbenzu et al., GCN Circ. 12780) is
detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 05:05:08.86 = 76.28692 (deg.)
Dec (J2000) = -84:42:39.1 = -84.71085 (deg.)
with an estimated uncertainty of 0.55 arc sec. (radius, 90% confidence).
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) 87 237 147 18.78 +/- 0.10
white 5230 5430 200 20.48 +/- 0.27
v 630 649 20 17.70 +/- 0.49
b 554 574 20 18.75 +/- 0.53
u (FC) 300 549 250 19.03 +/- 0.23
u 4820 5020 200 20.67 +/- 0.53
w1 679 6251 413 >20.4
m2 4410 6046 393 >20.4
w2 779 22585 1597 >21.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.18 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 12782
Subject
GRB 111229A: Faulkes Telescope South observations
Date
2011-12-30T12:16:31Z (14 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB)
report on behalf of the LJMU GRB group:
The 2-m Faulkes Telescope South observed Swift
GRB 111229A (Lien et al. GCN Circ. 12774)
on December 30, from 10:08 UT, corresponding to
11.5 hours after the BAT trigger time.
We clearly detect the optical afterglow (Nicuesa
Guelbenzu et al. GCN Circ 12775; Cucchiara et al.
GCN Circ. 12777) in the R filter and marginally
in the i' filter with the following magnitude:
Mid time from Total Exp Filter Magnitude Limit
trigger (hr) (s)
--------------------------------------------------------
11.77 6x300 i' 21.6 +- 0.5 >20.9
12.34 6x300 R 21.4 +- 0.1
--------------------------------------------------------
Magnitudes are calibrated against nearby USNOB-1 stars.
Comparing with GROND observations (Nicuesa Guelbenzu
et al GCN 12775), we derive an average power-law decay
index of about 0.8.
GCN Circular 12781
Subject
GRB 111229A: Swift-XRT refined Analysis
Date
2011-12-30T10:55:04Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), B.
Sbarufatti (INAF-OAB/PSU), G. Stratta (ASDC), P. D'Avanzo (INAF-OAB),
M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne
(U. Leicester) and A.Y. Lien report on behalf of the Swift-XRT team:
We have analysed 6.7 ks of XRT data for GRB 111229A (Lien et al. GCN
Circ. 12774), from 93 s to 22.6 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Osborne et al. (GCN. Circ 12780).
The late-time light curve (from T0+4.4 ks) can be modelled with a
power-law decay with a decay index of alpha=1.54 (+0.14, -0.13).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.06 (+0.17, -0.14). The
best-fitting absorption column is 1.9 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 1.0 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 3.7 x 10^-11 (5.5 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.9 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 1.0 x 10^21 cm^-2
Excess significance: 2.7 sigma
Photon index: 2.06 (+0.17, -0.14)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00510736.
This circular is an official product of the Swift-XRT team.
GCN Circular 12780
Subject
GRB 111229A: Enhanced Swift-XRT position
Date
2011-12-30T07:20:00Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 943 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 111229A, 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 = 76.28979, -84.71099 which is equivalent
to:
RA (J2000): 05h 05m 9.55s
Dec (J2000): -84d 42' 39.6"
with an uncertainty of 1.8 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 12777
Subject
GRB 111229A: Gemini-South Redshift
Date
2011-12-30T02:32:04Z (14 years ago)
From
Antonino Cucchiara at LBNL <acucchiara@lbl.gov>
A. Cucchiara (UCSC/UCO Lick), A. J. Levan (U. Warwick),
and N. Tanvir (U. Leicester) report:
On December 30.05 UT (157 minutes after the BAT trigger)
we observed the field of GRB 111229A (Lien et al., GCN 12774)
using GMOS-South on the Gemini-South 8-m telescope.
An optical afterglow is detected at a position reported by
Nicuesa Guelbenzu et al. (GCN 12775).
Subsequent spectroscopic observation of the optical afterglow of
GRB 111229A (range 5900-10080 Angstroms) reveals several absorption
features, including FeII2586,2600, MnII2606, MgII2796,2803
and MgII2853 at a common redshift of 1.3805.
We therefore suggest this to be the redshift of GRB 111229A.
We thank the Gemini staff for performing this observation,
in particular Pascale Hibon.
GCN Circular 12776
Subject
GRB 111229A: Swift-BAT refined analysis
Date
2011-12-30T02:12:44Z (14 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 111229A (trigger #510736)
(Lien, et al., GCN Circ. 12774). The BAT ground-calculated position is
RA, Dec = 76.561, -84.687 deg which is
RA(J2000) = 05h 06m 14.5s
Dec(J2000) = -84d 41' 14.8"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 78%.
The mask-weighted light curve shows an initial peak starting at ~T-2 sec,
peaking at ~T+1 sec, and returning to baseline at ~T+7 sec. The second
weaker peak starts at ~T+15 sec and ends at ~T+22 sec. T90 (15-350 keV)
is 25.4 +- 5.0 sec (estimated error including systematics).
The time-averaged spectrum from T-0.97 to T+26.15 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.85 +- 0.33. The fluence in the 15-150 keV band is 3.4 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.12 sec in the 15-150 keV band
is 1.0 +- 0.2 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/510736/BA/
GCN Circular 12775
Subject
GRB 111229A: GROND afterglow candidate
Date
2011-12-30T01:57:34Z (14 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
A. Nicuesa Guelbenzu, S. Klose, D. A. Kann (all TLS Tautenburg), and J.
Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 111229A (Lien et al., GCN 12774)
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 on La Silla.
Observations started in twilight, at 00:45 UT on December 30, 2.12 hr
after the burst. In the refined XRT error circle (Lien et al., GCN 12774),
we detect a new source in all bands which is significantly brighter than
the DSS2 limit at RA, DEC (J2000) = 05:05:08.84, -84:42:38.7. At a mean
time of December 30, 00:51 UT, in an 8min exposure, we measure the
following preliminary magnitudes (AB system):
g' = 20.50 +/- 0.04,
r' = 19.96 +/- 0.03,
i' = 19.74 +/- 0.03,
z' = 19.58 +/- 0.03,
J = 19.01 +/- 0.11.
We propose this source to be the afterglow of GRB 111229A, implying a
redshift of less than 3.5.
After correcting for a Galactic reddening of 0.18 mag, the SED is best fit
with a spectral slope of 0.72 +/- 0.06.
Optical data are calibrated against GROND zero points and NIR data against
2MASS field stars. Observations are continuing.
GCN Circular 12774
Subject
GRB 111229A: Swift detection of a burst
Date
2011-12-29T22:55:19Z (14 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
A. Y. Lien (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
S. Campana (INAF-OAB), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC),
S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),
H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA),
A. Melandri (INAF-OAB), J. L. Racusin (NASA/GSFC),
P. Romano (INAF-IASFPA), E. Troja (NASA/GSFC/ORAU) and
B.-B. Zhang (PSU) report on behalf of the Swift Team:
At 22:37:52 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 111229A (trigger=510736). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 76.282, -84.723, which is
RA(J2000) = 05h 05m 08s
Dec(J2000) = -84d 43' 20"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows two or three peaks
with a total duration of about 25 sec. The peak count rate
was ~1300 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 22:39:15.5 UT, 83.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 76.2885, -84.7108 which
is equivalent to:
RA(J2000) = 05h 05m 09.25s
Dec(J2000) = -84d 42' 38.8"
with an uncertainty of 2.5 arcseconds (radius, 90% containment). This
location is 43 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. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.04 x
10^21 cm^-2, Kalberla et al. 2005), with an excess column of 9.2
(+7.65/-5.74) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White
filter starting 87 seconds after the BAT trigger. No credible
afterglow candidate has been found in the initial data products. The
2.7'x2.7' sub-image processing failed because of no aspect solution.
Results from the list of sources generated on-board are not available
at this time. A full analysis will not be possible until the full data
set is downlinked.
Burst Advocate for this burst is A. Y. Lien (yarleen AT gmail.com).
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.)