GRB 081109A, GRB 081109
GCN Circular 8636
Subject
Radio observation of GRB 081109 with ATCA
Date
2008-12-08T04:16:50Z (17 years ago)
From
Aquib Moin at CIRA/ATNF <aquib.moin@postgrad.curtin.edu.au>
Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope
National Facility), Steven Tingay (Curtin Institute of Radio Astronomy),
Chris Phillips (Australia Telescope National Facility), Gregory Taylor
(University of New Mexico), Mark Wieringa (Australia Telescope National
Facility) and Ralph Martin (Perth Observatory) report:
We observed the REM position of the GRB 081109 optical afterglow (GCN
8501) at 4.800 and 4.928 GHz with the Australia Telescope Compact Array
(ATCA) between 01:15:05 UT, November 24, 2008 and 20:35:30 UT, November
25, 2008.
We did not detect a radio source at the optical afterglow position of
the GRB 081109 (GCN 8501). The data at 4.800 and 4.928 GHz were merged
and the radio flux density at the afterglow position found out to be 25
+/- 92 uJy/beam (1-sigma).
The Australia Telescope Compact Array (/ Parkes telescope / Mopra
telescope / Long Baseline Array) is part of the Australia Telescope
which is funded by the Commonwealth of Australia for operation as a
National Facility managed by CSIRO.
See the 4.800 & 4.928 GHz combined image at:
http://cira.ivec.org/dokuwiki/doku.php/grb/grb081109_field_image
GCN Circular 8523
Subject
GRB 081109A: confirmation of possible detection host galaxy
Date
2008-11-17T00:02:24Z (17 years ago)
From
Paul Kuin at MSSL <npkuin@googlemail.com>
N. P. M. Kuin (MSSL/UCL) and S. Immler(CRESST/GSFC/UMD) report on
behalf of the Swift UVOT team.
Continued observations by the Swift UltraViolet/Optical Telescope
(UVOT) of the field of GRB 081109A (Immler et al., GCN Circ. 8500,
Kuin and Immler, GCN Circ. 8504, Immler et al., GCN Circ. 8509)
confirm that a weak source is present close to the REM position
(D'Avanzo et al, GCN Circ. 8501) and also close to the refined
XRT position (Beardmore et al., GCN Circ. 8506).
We detect a constant source in 166 images totaling 54.4 ks of exposure time
over a period of 544 ks (~1 week) in the UVOT white filter at position:
RA = 22:03:09.579, Dec = -54.42.40.49 (J2000)
with an uncertainty of 0.8 arcsec (90% confidence). The source
magnitude in the summed image is wh = 22.86 +/- 0.09 mag (11.5 sigma detection).
The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383,627). They are not corrected for the
expected galactic reddening of E(B-V) = 0.019 in the direction of
the burst (Schlegel et al. 1998).
We interpret this image as the possible host galaxy. In that case the
REM position offset suggests that the GRB took place on the edge of the
host galaxy. The source we detect is also just outside the XRT error
circle.
GCN Circular 8517
Subject
GRB 081109: TAROT La Silla observatory optical observations
Date
2008-11-12T09:21:09Z (17 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz, A. (CESR-OMP), Gendre B. (LAM-OAMP),
Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 081109 detected by SWIFT
(trigger 334112) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.
The observations started 29.4s after the GRB trigger.
The elevation of the field decreased from
11 degrees above horizon and weather conditions
were excellents.
The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect the afterglow mentioned by D'Avanzo et
al. (GCNC 8501) with a limiting magnitude of:
t0+29.4s to t0+89.4s : R > 16.9
This image was taken during the gamma emission.
This means that there was no bright optical flash
associated to this burst.
The second image is 30.0s exposure in tracking mode.
We detect the afterglow:
t0+95.1s to t0+125.1s : R ~ 17.8 +/- 0.2
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular 8515
Subject
GRB 081109: GROND redshift limit and host extinction
Date
2008-11-10T19:25:43Z (17 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
C. Clemens, T. Kruehler, J. Greiner (all MPE Garching) report on
behalf of the GROND team:
We report on further analysis of the GROND data of GRB 081109 detected
by Swift (trigger 334112; Immler et al., GCN #8500) and Fermi/GBM
(von Kienlin 2008, GCN #8505) taken simultaneously in g'r'i'z'JHK.
In a combined 2~h exposure at a midtime of 18.5~hours after the burst,
we clearly detect the afterglow reported by D'Avanzo et al. (GCN
#8501) and Clemens et al. (GCN #8510) in all filters.
Using 2MASS field stars in JHK and the GROND zeropoints in g'r'i'z' we
estimate preliminary AB magnitudes of
g' = 23.14 +- 0.18 mag,
r' = 22.55 +- 0.15 mag,
i' = 22.00 +- 0.16 mag,
z' = 21.54 +- 0.15 mag,
J = 20.49 +- 0.07 mag,
H = 19.56 +- 0.06 mag and
K = 18.84 +- 0.10 mag
which have been corrected for the expected Galactic reddening of
E_(B-V)=0.02 (Schlegel et al. 1998).
Assuming Ly-alpha absorption, the g' band detection implies a redshift
of z < 3.5.
The Galactic foreground corrected broad band SED is best fit with a
power law template and significant extinction in the host. Depending
on the used model, the best fit intrinsic extinction A_V^{host}
varies between 0.6 and 1.2. We caution however, that this is strongly
dependent on the unknown redshift and subject to changes due to an
future improved calibration.
GCN Circular 8510
Subject
GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
Date
2008-11-10T03:34:52Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
C. Clemens, T. Kruehler, J. Greiner (all MPE Garching) and G. Szokoly
(Eoetvoes Univ., Budapest and MPE) report on behalf of the GROND team:
We observed the field of GRB 081109 (Swift trigger #334112; Immler et al., GCN
#8500) 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 started at 00:08 UT on November 10th, 2008, 17.1 hr after the GRB
trigger, and are continuing. They were performed during astronomical twilight
at an average seeing of 1.0" and at an average airmass of 1.1 as well as
under bright Moon.
Based on the first 7.7 min of total exposures in g'r'i'z' and 8.0 min in JHK,
we detect the afterglow candidate reported by D'Avanzo et al. (GCN #8501) and
estimate preliminary magnitudes (all in AB system) of
g' > 22.8
r' ~ 22.8 +/- 0.3
i' ~ 21.8 +/- 0.15
z' ~ 21.4 +/- 0.15
J ~ 20.4 +/- 0.10
H ~ 19.7 +/- 0.15
K ~ 18.9 +/- 0.20
These magnitudes are calibrated against GROND zeropoints as well as
2MASS field stars.
The spectral energy distribution is very red, and requires an extinction
of A_V > 0.5. With this strong extinction, and our g'-band limit being
compromised by the nearby full Moon, we cannot derive a redshift
at this stage.
GCN Circular 8509
Subject
GRB 081109A: Possible Swift-UVOT detection
Date
2008-11-10T01:35:23Z (17 years ago)
From
Stefan Immler at NASA/GSFC <stefan.m.immler@nasa.gov>
S. Immler (CRESST/UMD/GSFC), N. P. M. Kuin (MSSL/UCL), and S. T. Holland
(CRESST/USRA/GSFC) report on behalf of the Swift UVOT team:
Further analysis of Swift Ultraviolet/Optical Telescope (UVOT) data of
GRB 081109A (Immler et al., GCN Circ. 8500), starting 75 sec after the
BAT trigger, gives a tentative detection of an optical source at the
reported REM position (D'Avanzo et al., GCN Circ 8501) in the white
filter at a 3.3-sigma level of confidence. The source is not detected in
any of the other UVOT filters at the limiting magnitudes reported below.
Filter Tstart(s) Tstop(s) Exp(s) Magnitude
wh 75 6592 745 21.6+/-0.3
u 287 6181 501 >21.5 (3-sigma UL)
b 543 6387 452 >20.9 (3-sigma UL)
uvw2 593 5362 274 >21.6 (3-sigma UL)
v 617 5566 274 >20.9 (3-sigma UL)
uvm2 641 5771 274 >21.5 (3-sigma UL)
uvw1 666 5976 255 >21.5 (3-sigma UL)
The possible detection in the white filter, combined with the lack of a
detection in the v filter, is consistent with the source having a
redshift greater than 5.5.
Follow-up observations, especially in the infrared, are encouraged.
GCN Circular 8508
Subject
GRB 081109A: Faulkes Telescope South observations
Date
2008-11-09T19:27:53Z (17 years ago)
From
David Bersier at Liverpool John Moores U <dfb@astro.livjm.ac.uk>
C. Guidorzi (INAF-OAB), D. Bersier, M. Burgdorf, C.G. Mundell (LJMU)
and N. Tanvir (U. Leicester) report on behalf of a larger collaboration:
We observed GRB 081109A (Immler et al. GCN Circ. 8500) with the 2m
Faulkes Telescope South starting on November 11 at 11:50:36 UT
(corresponding to 4.81 hours post burst) in the R and i' filters.
We do not detect any object at the position of the REM afterglow
(D'Avanzo et al., GCN Circ 8501) down to magnitudes 21.0 and 21.2
in the R and i' filters respectively.
These upper limits are conservative however, as there is a possible
flux excess at the position of the REM afterglow but further analysis
is required to ascertain the reality of this source.
The calibration was performed using the R2 and I values of the
nearby USNOB1 star RA=22:03:01.679, Dec=-54:43:07.05 (R2=16.88, I=16.46).
GCN Circular 8507
Subject
GRB 081109A, Swift-BAT refined analysis
Date
2008-11-09T16:42:12Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
C. B. Markwardt (GSFC/UMD), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
S. Immler (CRESST/GSFC/UMD), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 081109A (trigger #334112)
(Immler, et al., GCN Circ. 8500). The BAT ground-calculated position is
RA, Dec = 330.798, -54.711 deg, which is
RA(J2000) = 22h 03m 11.5s
Dec(J2000) = -54d 42' 40.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73%.
The mask-weighted light curve shows a smooth rise to a single peak
starting at ~T-90 sec, peaking at ~T+5 sec, and roughly exponentially decaying
back to baseline at ~T+400 sec.
T90 (15-350 keV) is 190 +- 60 sec (estimated error including systematics).
The time-averaged spectrum from T-15.9 to T+416.1 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.72 +- 0.09. The fluence in the 15-150 keV band is 3.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+7.64 sec in the 15-150 keV band
is 1.1 +- 0.0 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/334112/BA/
GCN Circular 8506
Subject
GRB 081109A: Swift-XRT refined analysis
Date
2008-11-09T16:19:07Z (17 years ago)
From
Andy Beardmore at U Leicester <apb@star.le.ac.uk>
A.P. Beardmore, K.L. Page (U. Leicester) and S. Immler (CRESST/GSFC/UMD)
report on behalf of the Swift-XRT team.
The Swift-XRT started observing the field of GRB 081109A (trigger
#334112, Immler et al., GCN 8500) at 07:03:12.2 UT, 65.6 s after
the BAT trigger. The XRT observed the GRB in Windowed Timing (WT) mode
until 318 s after the trigger and Photon Counting (PC) mode thereafter.
Using 4661 s of XRT Photon Counting mode data and 7 UVOT images, we
find an astrometrically corrected X-ray position (using the XRT-UVOT
alignment and matching to the USNO-B1 catalogue) of
RA, Dec = 330.7905, -54.7118 which is equivalent to :
RA (J2000): 22h 03m 9.72s
Dec (J2000): -54d 42m 42.5s
with an uncertainty of 1.4 arcsec (90% confidence). This is 2.98
arcsec from the reported possible NIR counterpart of D'Avanzo (GCN
8501).
The X-ray light curve from the first three orbits can be modelled with
a broken powerlaw with an initial decay slope of 1.78 +/- 0.06, a break
time of 353 +/- 40 s, followed by a shallower decay slope of 0.99 +/- 0.04.
The spectrum of the WT data from orbit 1 (from T+71.9 s to T+318.4 s,
where T is the trigger time) can be well fit by an absorbed powerlaw
with a photon index of 1.72 +/- 0.08 and column density of
(1.84 +/- 0.22) x 10^21 cm^-2, compared with the Galactic column
density of 1.6 x 10^20 cm^-2 in the direction of the burst. The observed
0.3-10 keV flux is (7.4 +/- 0.4) x 10^-10 erg cm^-2 s^-1. The
corresponding unabsorbed 0.3-10 keV flux is (9.5 +/- 0.5) x 10^-10
erg cm^-2 s^-1.
A powerlaw fit to a spectrum obtained from PC mode data spanning
orbits 2 to 3 (T+4.76 ks to T+12.88 ks) is best fit with a photon
index of 2.20 +/- 0.20 and column density (3.1 +/- 0.7) x 10^21 cm^-2.
The observed 0.3-10 keV flux over this interval is (7.3 +/- 0.7) x 10^-12
erg cm^-2 s^-1. The count-to-observed-flux conversion factor is
6.0e-11 erg cm^-2 count^-1.
Assuming the X-ray emission from the burst continues to decline at the
same rate we predict an XRT count rate of 0.018 count s^-1 at T+24 hour,
or an observed 0.3-10 keV X-ray flux of 1.1 x 10^-12 erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.
GCN Circular 8505
Subject
GRB 081109: Fermi GBM detection
Date
2008-11-09T15:56:47Z (17 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 07:02:02.42 UT on 09 November 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081109 (trigger 247906923 / 081109293), which was
also detected by the SWIFT (S. Immler et al. 2008, GCN 8500).
The GBM on-ground location is consistent with the Swift position.
The GBM light curve shows a single peak
with a duration (T90) of about 45 s (8-1000 keV).
The time-averaged spectrum from T0-6.144 s to T0+26.624 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -1.28 +/- 0.09 and
the cutoff energy, parameterized as Epeak is 240 +/- 60 keV.
(chi squared 510 for 478 d.o.f.)
The event fluence (8-1000 keV) in this time interval is
(6.53 +/- 0.43)E-06 erg/cm^2. The 1-sec photon flux measured
starting from T0+9.216 s in the 8-1000 keV band
is 3.2 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 8504
Subject
GRB 081109: Swift/UVOT upper limits
Date
2008-11-09T15:18:19Z (17 years ago)
From
Paul Kuin at MSSL <npkuin@googlemail.com>
N. P. M. Kuin (MSSL/UCL) and S. Immler (CRESST/GSFC/UMD)
report on behalf of the Swift UVOT team.
The Swift UltraViolet/Optical Telescope (UVOT) began observing
GRB 081109 (Swift BAT trigger number 334112; Immler et al.,
GCN Circ. 8500) on November 9, 2008, with a white filter finding
chart at 07:03:23 UT, 75 seconds after the trigger.
No new source is detected in any of our images at the position
consistent with the reported XRT position in GCN Circ. 8500.
The magnitudes and upper limits for GRB081109 at this position
are given below:
Filter Tstart(s) Tstop(s) Exp(s) Magnitude
wh 75 6592 745 >21.49 (3-sigma UL)
u 287 6181 501 >20.57 (3-sigma UL)
b 543 6387 452 >20.35 (3-sigma UL)
uvw2 593 5362 274 >20.03 (3-sigma UL)
v 617 5566 274 >19.09 (3-sigma UL)
uvm2 641 5771 274 >19.87 (3-sigma UL)
uvw1 666 5976 255 >20.00 (3-sigma UL)
The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383, 627). They are not corrected for
the expected galactic reddening of E(B-V) = 0.019 in the direction
of the burst (Schlegel et al. 1998).
GCN Circular 8503
Subject
GRB 081109A optical upper limit
Date
2008-11-09T14:15:04Z (17 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Peter Nelson (Ellinbank, Victoria, Australia) reports to the AAVSO
International High Energy Network the following optical observation of
GRB081109A (GCN #8500 Immler et al.; GCN #8501 D'Avanzo et al.):
Peter Nelson has obtained a limiting magnitude on the optical afterglow of
GRB081109A (Immler et al., GCN #8500). The near IR afterglow position RA:
22:03:09.72 Dec: -54:42:39.5 found by D'Avanzo et al. (GCN #8501) was observed
for 120 seconds using a 0.32-meter Newtonian with an SBIG ST8XE
CCD and an R filter under poor photometric conditions. The mid-point of
the observations was 2008 Nov 09.5188 UT, approximately 5.4 hours after the
burst. The afterglow was not detected to an upper limit of R=18.1, using
the USNO-A2.0 star 0300-37476396 (R=13.2) as the comparison.
A detailed report of these observations is available on the AAVSO website
at ftp://ftp.aavso.org/grb/PeterNelson_081109_2454780.06997_.txt
A fits image is available at
ftp://ftp.aavso.org/grb/PeterNelson_081109_2454780.06997_.fits
The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network.
GCN Circular 8501
Subject
GRB 081109: REM NIR afterglow detection
Date
2008-11-09T09:54:49Z (17 years ago)
From
Stefano Covino at Brera Astronomical Observatory <stefano.covino@gmail.com>
P. D'Avanzo, S. Covino, L.A. Antonelli, D. Malesani, D. Fugazza, L.
Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini,
V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C.
Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E.J.A.
Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella,
G. Stratta, G. Tagliaferri, G. Tosti, V. Testa, S.D. Vergani, F.
Vitali report on behalf of the REM team:
The robotic 60-cm REM telescope located at La Silla (Chile) observed
automatically the field of the GRB 081109 (Immler et al. GCN 8500) on
Nov 09 starting about 52 s after the burst. Observations were
carried out at high airmass (~ 6). We clearly detect an object in our
first K-band image inside the XRT error box (Immler et al. GCN 8500)
at the following coordinates (J2000):
R.A. = 22:03:09.72
Dec = -54:42:39.5
with an uncertainty of 1.0". The object is not visible in the single
RJH images taken approximately at the same epoch. Coadding all the
available RJH images taken around the same epoch we obtain the
following results:
Mean_obs texp #frames_coadd Filter Mag
Nov 09.30604 UT 780 s 11 R > 16.5 (3sigma)
Nov 09.30707 UT 65 s 4 J > 15.8 (3sigma)
Nov 09.29936 UT 75 s 7 H 15.47 � 0.26
Nov 09.30145 UT 10 s 1 K 14.51 � 0.27
The object subsequently brightened, reaching K = 14.27 � 0.16 on Nov
09.30612 UT. No object is detected at this position in the 2MASS and
USNO catalogs. We propose this is the NIR afterglow of GRB 081109. We
cannot indeed exclude the possibility that the lack of detection
blueward of the H band is due to an high-redshift nature of this
event. We note, however, that the large airmass badly affects the
images in the J and R bands, so that our limits are not very
constraining
Further deep optical/NIR observations are encouraged.
GCN Circular 8500
Subject
GRB 081109: Swift detection of a burst
Date
2008-11-09T07:22:59Z (17 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
S. Immler (CRESST/GSFC/UMD), A. P. Beardmore (U Leicester),
J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), S. D. Hunsberger (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL),
M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:
At 07:02:06 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 081109 (trigger=334112). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 330.787, -54.719 which is
RA(J2000) = 22h 03m 09s
Dec(J2000) = -54d 43' 06"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a triangular
structure with a duration of about 40 sec. The peak count rate
was ~2500 counts/sec (15-350 keV), at 20 sec after the trigger.
The XRT began observing the field at 07:03:12.2 UT, 65.6 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 330.7911, -54.7114 which is equivalent to:
RA(J2000) = 22h 03m 09.86s
Dec(J2000) = -54d 42' 41.0"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 28 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
The initial flux in the 2.5 s image was 4.78e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 75 seconds after the BAT trigger. The 2.7'x2.7' sub-image covers 100%
of the XRT error circle. The typical 3-sigma upper limit has been about 19.6
mag. 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 0.02. No afterglow candidate has been detected.
Burst Advocate for this burst is S. Immler (immler AT milkyway.gsfc.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.)