GRB 060111
GCN Circular 4490
Subject
GRB 060111(a): P60 Observations
Date
2006-01-12T01:22:35Z (20 years ago)
From
S. Bradley Cenko at Caltech <cenko@srl.caltech.edu>
S. B. Cenko, A. M. Soderberg, E. Ofek (Caltech) and D. B. Fox (Penn State)
report on behalf of the Caltech-NRAO-Carnegie Collaboration:
We have imaged the field of GRB 060111(a) (Zane et al., GCN 4479) with the
automated Palomar 60-inch telescope. Observations consisted of 9 x 180 s
exposures in the Kron R-band taken at a mean epoch of 13:19:49 11 January
UT (~ 8.9 hours after the burst trigger).
We find no sources in the revised XRT error circle (Goad et al., GCN 4481)
or at the location of the proposed UVOT counterpart (Blustin, Zane, and
Rosen, GCN 4482). The limiting magnitude of our observations, calculated
with respect to several Guide Star Catalog sources in the field, is R >
20.5.
GCN Circular 4486
Subject
GRB 060111: Swift-BAT Refined Analysis
Date
2006-01-11T20:16:06Z (20 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <jayc@milkyway.gsfc.nasa.gov>
G. Sato (ISAS), L. Barbier (GSFC), S. Barthelmy (GSFC),
J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC),
D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
F. Marshall (GSFC), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/ORAU), A. Smale (NASA HQ), J. Tueller (GSFC),
on behalf of the Swift-BAT team:
Using the data set from T-299 to T+303.0 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 060111 (trigger #176818)
(Zane, et al., GCN 4479). The BAT ground-calculated position is
(RA,Dec) = 276.195, 37.596 {18h 24m 47.3s, 37d 35' 44.1"} (deg; J2000)
+- 0.8 arcmin, (radius, sys+stat, 90% containment). The partial coding
was 98%.
The light curve is a single peak, rise slightly faster than its decay.
T90 (15-350 keV) is (13 +- 1) sec (estimated error including
systematics). There is a small bump of marginal significance in the
15-50 keV band at T+280, the time of the x-ray flare observed by the
XRT (GCN circ. #4481, Goad et al.).
The time-averaged spectrum from T-0.7 to T+14.7 is best fit by a
cut-off power law with an Epeak of (72 +14, -8) keV and a photon
index of 0.8 +- 0.3. The fluence in the 15-150 keV band is (1.18 +-
0.05) x 10^-06 erg/cm2. A simple power law also gives an acceptable
fit, with a photon index of 1.63 +/- 0.07 and a fluence of (1.25 +-
0.05) x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T+4.3 sec in the 15-150 keV band is (1.72 +- 0.15) ph/cm2/sec. All
the quoted errors are at the 90% confidence level.
GCN Circular 4483
Subject
GRB 060111: TAROT optical observation
Date
2006-01-11T15:44:08Z (20 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 060511 detected by SWIFT
(trigger 176818) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
First image was acquired 20s after the GCN trigger
(7s after the notice). The field elevation increased
from 23 degrees above horizon and weather conditions
were good. Moon was just rising (23 deg from the field)
at the begining of observations. Due to a technical
problem, there was no image between 261 and 510s
after the trigger.
We detected no new source comparing our individual
unfiltered images with the USNO-B1 catalog within
the error circle at the XRT position (Goad et al.
GCNC 4481).
From individual frames we give early limits:
Day : 2006-01-11
UT-start UT-end (sec since GRB) Exp(s) R-mag
04:23:25.7 - 04:24.25.7 20 - 80 60 >16.2 (one frame trailed)
04:24:32.4 - 04:25.02.4 86 - 116 30 >17.0 (one frame)
04:25:08.7 - 04:25.38.7 122 - 152 30 >17.0 (one frame)
04:31:36.2 - 04:33:06.2 510 - 600 90 >17.7 (one frame)
To increase the signal to noise, we co-added series frames.
The source at the XRT position (Goad et al. GCNC 4481) is
marginaly detected on the first co-addition:
Day : 2006-01-11
UT-start UT-end (sec since GRB) R-mag
04:24:32 - 04:27.27 86 - 261 ~18.3 (sum of 5 frames of 30s)
04:31:36 - 04:40.13 510 - 1027 >18.7 (sum of 6 frames of 90s)
Magnitudes were estimated with the nearby USNO-B1 stars.
This message may be cited.
GCN Circular 4482
Subject
GRB 060111: possible UVOT counterpart
Date
2006-01-11T13:31:24Z (20 years ago)
From
Alexander Blustin at MSSL-UCL <ajb@mssl.ucl.ac.uk>
A. J. Blustin (UCL-MSSL), S. Zane (UCL-MSSL), S. R. Rosen (UCL-MSSL)
on behalf of the Swift/UVOT team
Further analysis of the initial UVOT data for GRB 060111 (Zane et al.,
GCN 4479) reveals a potential afterglow candidate at
RA,Dec (J2000) = 18:24:49.132 +37:36:14.47
within the refined XRT error circle (Goad et al., GCN 4481). The
source, significant at 8 sigma in an 3 arcsec radius aperture, has a
V band magnitude of 18.9 +/- 0.4 in a 200 s exposure starting at 72 s
after the BAT trigger. This magnitude is uncorrected for Galactic
extinction (E(B-V) ~0.1).
GCN Circular 4481
Subject
GRB060111 : XRT refined analysis
Date
2006-01-11T13:23:02Z (20 years ago)
From
Michael Goad at U Leicester <mrg@star.le.ac.uk>
M.R. Goad, A.P. Beardmore, K. Page (U. Leicester), D. Burrows (PSU), R. Fink
(GSFC), M. Ajello (MPE) report on behalf of the Swift XRT team.
From analysis of 2.5 ks of Photon Counting mode data of GRB060111 (Zane et
al., GCN 4479) starting in the 2nd orbit of observations, we obtain a refined
XRT position of RA: 18h 24m 49.0s, Dec:+37d 36m 16.1s (J2000) with an
uncertainty of 3.6 arcsec (90% containment). This includes the latest XRT
boresight correction. This refined position is 25.1 arcsec from the BAT
on-board position and 5 arcsec from the XRT on-board position quoted in GCN
4479.
We have also analysed 400 s of XRT Windowed Timing mode observations starting
78 s after the BAT trigger. The XRT lightcurve displays 3 large flares with a
peak count rate of approximately 150 ct/s occurring 280 s after the BAT
trigger. The light-curve has an underlying powerlaw decay of slope -1.3.
The XRT WT mode 0.3-10 keV spectrum is well represented by an absorbed
powerlaw with photon index 2.35 +/-0.04 with a mean unabsorbed flux of 2.5e-9
ergs/cm2/s. We find evidence for excess NH of 2.4e21 cm^-2.
The predicted 0.3-10 keV unabsorbed flux 24 hours after the BAT trigger is
1.2e-13 ergs/cm2/s
GCN Circular 4480
Subject
GRB 060111: ROTSE-III Optical Limits
Date
2006-01-11T05:12:43Z (20 years ago)
From
Fang Yuan at ROTSE <yuanfang@umich.edu>
F. Yuan (U Mich), W. Rujopakarn (U Mich), E.S. Rykoff (U Mich), S.A.
Yost (U Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe,
Turkey, responded to GRB 060111 (Swift trigger 176818), producing images
beginning 5 s after the GCN notice time. An automated response took the
first image at 04:23:23.2 UT, 17.1 s after the burst, under twilight
conditions. We took 10 5-sec eposures before the individual images were
saturated due to twilight. These unfiltered images are calibrated
relative to USNO A2.0 (R).
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma error circle and particularly at the XRT position, for both
single images and coadding into sets of 10. Individual images have
limiting magnitudes ranging from 13.4-13.8; we set the following
specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
04:23:23.2 04:23:28.2 5 13.4 17.1 N
04:23:23.2 04:25:31.0 127.8 14.5 17.1 Y
GCN Circular 4479
Subject
GRB 060111: Swift detection of a burst
Date
2006-01-11T05:05:37Z (20 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
S. Zane (MSSL-UCL), S. Barthelmy (GSFC), A. Beardmore (U Leicester),
A. J. Blustin (UCL-MSSL), D. Burrows (PSU), J. Cummings (GSFC/NRC),
N. Gehrels (GSFC), M. Goad (U Leicester), J. Kennea (PSU),
C. Markwardt (GSFC/UMD), F. Marshall (GSFC), D. Palmer (LANL)
on behalf of the Swift team:
At 04:23:06 UT, Swift-BAT triggered and located GRB 060111 (trigger=176818).
The spacecraft slewed immediately. The BAT on-board calculated location is
RA,Dec 276.212d,+37.602d {18h 24m 51s,+37d 36' 08"} (J2000), with an
uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light
curve shows a single peak structure with a total duration of ~20 sec.
The peak count rate was ~3000 counts/sec (15-350 keV), at ~5 sec
after the trigger.
The XRT began observing the field at 04:24:12 UT (66 sec after the burst).
The instrument found a bright, variable, uncataloged X-ray source located at:
RA(J2000) = 18h 24m 48.9s
Dec(J2000) = +37d 36' 21"
This location is 27.4 arcseconds from the BAT position. The estimated
uncertainty is 8 arcseconds (90% confidence radius), including about 5
arcseconds systematic error due to an XRT boresight offset not currently
corrected on-board. The initial flux was 8E-10 ergs/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 200 seconds with the V filter
starting 72 seconds after the BAT trigger. No afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers
100% of the XRT error circle. The typical 3-sigma upper limit has been
about 18th 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 18.0 mag. No correction has been made for
the expected visual extinction of about 0.1 magnitudes.
We are currently in the portion of the orbits where the spacecraft does not
pass over the Malindi downlink station. Therefore, it will be at least
7 hours before we have access to the full data set for the refined analyses.