GRB 060204C
GCN Circular 4663
Subject
GRB 060204C: Swift-BAT detection of a burst
Date
2006-02-04T21:30:36Z (19 years ago)
From
Scott Barthelmy at NASA/GSFC <Scott@lheamail.gsfc.nasa.gov>
D. Grupe (PSU), S. Barthelmy (GSFC), D. Burrows (PSU),
A. Cucchiara (PSU), J. Cummings (GSFC/NRC), N. Gehrels (GSFC),
S. Hunsberger (PSU), J. Kennea (PSU), C. Markwardt (GSFC/UMD),
F. Marshall (GSFC), D. Morris (PSU), D. Palmer (LANL), T. Sakamoto (GSFC)
on behalf of the Swift team:
At 20:33:43 UT, Swift-BAT triggered and located GRB 060204C (trigger=180274).
The spacecraft slewed immediately. The BAT on-board calculated location is
RA,Dec 92.727d,+70.171d {06h 10m 54s,+70d 10' 14"} (J2000), with an
uncertainty of 3 arcmin (radius, 90% containment, stat+sys).
This is a 64-sec image trigger, and as such, there is little that can be
determined from the TDRSS lightcurve.
The S/C slewed immediately and the XRT began taking data at 20:36:19 UT,
157 sec after the BAT trigger. The XRT on-board centroid algorithm did not
converge and no prompt position is available, however, the XRT
lightcurve suggests the possibility of a decaying source in the field of view.
We are waiting for down-linked data to determine the presence of the source.
UVOT took a finding chart exposure of nominal 200 seconds with the V filter
starting 156 seconds after the BAT trigger. No afterglow candidate
has been found in the initial data products. Image catalog data
are not available at this time. The 8'x8' region for the list of sources
generated on-board covers 100% of the BAT error circle. The list
of sources is typically complete to about 18.0 mag. No correction
has been made for the expected extinction of about 0.6 magnitudes.
No afterglow candiate was found in a second B finding chart taken
at T+363 sec.
Given that the star tracker had been out-of-lock for only 2 minutes prior
to this trigger, it is very unlikely there is a problem with the attitude
of this position solution, so we believe this location to be valid.
GCN Circular 4664
Subject
GRB 060204C: ROTSE-III Optical Limits
Date
2006-02-04T21:55:29Z (19 years ago)
From
Eli Rykoff at U of Michigan/ROTSE <erykoff@umich.edu>
E.S. Rykoff (U Mich), S.A. Yost (U Mich), B. E. Schaefer (Louisiana
State), F. Yuan (U Mich), T. Guver (U Istanbul), report on behalf of the
ROTSE collaboration:
ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe,
Turkey, responded to GRB 060204C (Swift trigger 180274, GCN 4663),
producing images beginning 6.8 s after the GCN notice time. An automated
response took the first image at 20:35:04.8 UT, 81.8 s after the burst,
under windy conditions. We took 10 5-sec, 10 20-sec and 31 60-sec
eposures. 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 BAT error circle, for both single images and coadding into sets
of 10. Individual images have limiting magnitudes ranging from
16.1-17.7; we set the following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
20:35:04.8 20:35:09.8 5 16.1 81.8 N
20:35:04.8 20:37:11.5 126 17.7 81.8 Y
20:37:20.2 20:41:56.3 276 18.2 217.2 Y
GCN Circular 4665
Subject
GRB 060204C: Liverpool Telescopes optical limit
Date
2006-02-04T23:32:29Z (19 years ago)
From
Andrea Melandri at Liverpool John Moores U <axm@astro.livjm.ac.uk>
A. Melandri, C.G. Mundell, A. Monfardini, A. Gomboc,
C. Guidorzi, R.J. Smith, I.A. Steele, C.J. Mottram,
D. Bersier, S. Kobayashi, M. Burgdorf, D. Carter and
M.F. Bode (Liverpool JMU) report:
"On Feb 04.86 UT the Liverpool Telescope robotically
followed up the field of GRB060204C (Swift trigger 180274,
Grupe et al, GCN 4663), beginning at 6.42 minutes after
the burst event.
The automatic "detection mode" procedure did not detect any
obvious afterglow candidate brighter than about R=18.7 mag
from 3x10-s images, confirmed by visual inspection.
We note the presence of two bright stars in the field of
view that limits our detection capabilities in the
surrounding halos.
This message can be cited"
GCN Circular 4666
Subject
GRB 060204C: BOOTES-IR optical limits
Date
2006-02-05T00:30:01Z (19 years ago)
From
Martin Jelinek at Inst.Astrophys.Andalucia,Granada <mates@iaa.es>
S. Guziy, S. Vitek, M. Jelinek, A.J. Castro-Tirado, A. de
Ugarte Postigo, S.B. Pandey, J. Gorosabel, R. Cuniffe and S.C.
Castillo (IAA Granada, Spain),
P. Kubanek (ASU Ondrejov, Czech Rep. and ISDC Versoix, Switzerland),
M.D. Sabau-Graziati (INTA Madrid, Spain) and
R. Hudec (ASU Ondrejov, Czech Rep.),
on behalf of larger colaboration
report
The 60cm robotic telescope BOOTES-IR located at Observatorio
Sierra Nevada, Southern Spain, observed automatically the
position of GRB060204C (Grupe et al. GCN 4663). The telescope
slewed automatically within 3m5s after recieving the GCN alert
and immediately started the observation. We do not see any
optical transient in the GRB errorbox down to the foillowing
3-sigma limits:
mean time after GRB exposure limit filter
===================================================
7m20s 70s 17.8 Rj
19m5s 270s 18.9 Rj
===================================================
Note that BOOTES-IR is still in comissioning phase operating
without the IR camera.
This message may be cited.
GCN Circular 4668
Subject
GRB 060204C: OSN limits
Date
2006-02-05T00:38:48Z (19 years ago)
From
Martin Jelinek at Inst.Astrophys.Andalucia,Granada <mates@iaa.es>
Martin Jelinek, D. Martinez, S. Guziy, S. Vitek
and A. de Ugarte Postigo (IAA Granada, Spain)
report:
We imaged the error box of Swift GRB060204C (Grupe et al. GCN
4663) with the 1.5m telescope at Observatorio Sierra Nevada.
We do not detect any new or variable source within the BAT
error box down to the limiting magnitude I=21.0 at an image
obtained 38minutes after the GRB. The image is calibrated
against USNO-B1.0 I2 magnitude. Further observations are in
progress.
This message may be cited.
GCN Circular 4672
Subject
Swift XRT Observation of GRB 060204C
Date
2006-02-05T05:02:35Z (19 years ago)
From
Dirk Grupe at PSU/Swift-XRT <grupe@astro.psu.edu>
D. Grupe, J. A. Kennea, and D. N. Burrows (PSU) report on behalf of the
Swift XRT team:
The Swift XRT began observing the field of BAT trigger 180274 (presumed
to be GRB 060204C) at 20:36:20 (157 seconds after the BAT trigger). In
the first 4 orbits of data (total exposure 8.0 ks) we find no evidence
for any source within the BAT error circle.
We place an upper limit of 1e-14 ergs/s/cm2 on any X-ray counterpart to
this event.
We do find a fairly bright source 8 arcminutes from the BAT position at
(RA, Dec, J2000) = (06:12:23.0, +70 12 42.9), but this object is not
fading and appears to be coincident with an object in the DSS (but not
in the ROSAT All-sky survey).
We note that it is extremely unusual for the XRT to slew promptly to a
long GRB and not find a bright X-ray source in the field of view. In
fact, there have been no previous cases in which the XRT slewed to a
long GRB field in less than 300 seconds and did not detect an afterglow.
This Circular is an official product of the Swift XRT Team.
[GCN OPS NOTE(05feb06): Per author's request, the Subject-line
was changed from "060402C" to "060204C".]
GCN Circular 4673
Subject
GRB 060204C: optical observations
Date
2006-02-05T05:10:38Z (19 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
S. Piranomonte (INAF/OARm), D. Malesani (SISSA), H. Navasardyan
(INAF/OAPd), N. Masetti (INAF/IASF Bo), report on behalf of a larger
collaboration:
We observed the field of GRB 060204C (Grupe et al., GCN 4663) with the
Asiago telescope equipped with the AFOSC camera. Ten exposures lasting 3
minutes each were acquired, starting on 2006 Feb 4.9009 UT (mean time
Feb 4.9172 UT, i.e. 1.45 hr after the GRB). The seeing was quite bad
(~2.4 arcsec).
Visual inspection of the coadded frame reveals no new objects inside the
whole BAT error circle, after comparison with the DSS-II. The limiting
magnitude of our images is estimated to be R ~ 21.8 (calibrated against
the USNO-B1 catalog).
Our images do not cover the position of the XRT source mentioned in GCN
4672 (Grupe et al., GCN 4672), which lies outside the BAT error circle.
This message can be cited.
GCN Circular 4678
Subject
GRB060204C: optical observation
Date
2006-02-05T19:40:13Z (19 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev (Institute of Astronomy), A. Pozanenko (IKI) on behalf of
larger GRB follow up collaboration report:
We observed the field of GRB 060204C (Grupe et al., GCN 4663) in R-band
with the 60 cm telescope of peak Terskol observatory starting Feb. 04 (UT)
20:56. Totally we obtained 27x60 s images in two epochs (UT) 20:56-21:10,
and 21:22-21:35. Within whole BAT error circle in a combined image we found
an object which is marginally visible in DSS2(R) and not presented in
USNO-B1.0; coordinates of the object are (J2000) RA= 06h 10m 38.4s Dec=
+70 09 32.4 with uncertainty in both coordinates of about 0.1". Brightness
of the object is measured in the combined image is R=19.2 +/-0.1. The object
is not variable between the two epochs within error bars. The astrometry
and photometry calibration is based on USNO-B1.0.
While the object is not variable between our epochs and marginally visible
in DSS2(R) and detected better in DSS2(I), the object may be a host galaxy
of GRB060204C if fading brightness of the object will be confirmed.
The stacked image can be found in
http://grb.rssi.ru/GRB060204c/grb060204C_Z600_R.jpg
GCN Circular 4679
Subject
BAT GRB 060204C is probably not a GRB
Date
2006-02-05T23:09:37Z (19 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>
T. Sakamoto (GSFC/ORAU), L. Barbier (GSFC), S. Barthelmy (GSFC),
P. Boyd (GSFC-UMBC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL),
N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC),
G. Sato (ISAS), J. Tueller (GSFC), W. Voges (MPE)
on behalf of the Swift-BAT team:
Using the data set from T-299.0 to T+303.1 sec from the recent telemetry
downlink, we report further analysis of BAT trigger #180274
(Grupe, et al., GCN 4663). The BAT ground-calculated position is
(RA,Dec) = 92.715, 70.174 deg {6h 10m 58.5s, 70d 10' 41.7"} (J2000)
+- 3.6 arcmin, (radius, sys+stat, 90% containment). The partial coding
was 39%. The mask-weighted light curve shows a single broad peak in
the 15-50 keV band with no significant emission above 50 keV.
T90 (15-350 keV) is (60 +- 5) sec (estimated error including systematics).
The time-averaged spectrum from T+0 to T+64 is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.4 +- 0.6. The fluence in the 15-150 keV band is
(3.5 +- 1.2) x 10^-07 erg/cm2. The average photon flux measured from
T+0 to T+64 sec in the 15-150 keV band is (0.10 +- 0.03) ph/cm2/sec.
All the quoted errors are at the 90% confidence level.
This source was detected at the 4.8-sigma level 1.5 days earlier
at the same location. There is 0.1% probability that this pre-trigger
detection is a chance coincidence. This plus the very soft nature
of the spectrum forces us to conclude that this is probably not a
real GRB, but is very likely a hard X-ray transient.
Further analysis has shown that even though the star tracker had a
loss-of-lock during the initial trigger, the tracking error was much
smaller than our stated location uncertainty.
GCN Circular 4681
Subject
GRB 060204C: XRT analysis of Swift J061223.0+701243.9
Date
2006-02-06T01:48:11Z (19 years ago)
From
Dirk Grupe at PSU/Swift-XRT <grupe@astro.psu.edu>
authors: D. Grupe (PSU), D. Burrows (PSU)., D. Morris (PSU),
T. Sakamoto (GSFC), N. Cucchiara (PSU), A. Retter (PSU),
S. Barthelmy (GSFC)
on behalf of the Swift team
We report on the analysis of the X-ray source Swift J061223.0+701243.9
which is inside the Field of view of BAT trigger 180274
(GRB 060204C).
As discussed by Grupe et al (GCN 4672) this source
is about 8' away from the BAT position reported by Grupe et al.
(GCN 4663). The XRT position of this source is:
RA-2000: 06 12 22.97
Dec-2000: +70 12 43.9
with an error radius of 3.6"
Note that even though there was a star tracker loss-of-lock during
the initial trigger, we consider this position as very reliable. The
total exposure time of the field is 22.6 ks which were acquired
within 58.2 ks.
The light curve initially shows a brightening followed by a
decreasing count rate starting about 10 ks after the trigger.
Below we list the light curve with time after the trigger
(in seconds), count rate and count rate error (in units of XRT
counts/s):
Time cr cr_err
------------ ------- ----------
2.61399e+02 1.82e-02 7.03e-03
5.25616e+03 5.94e-02 4.88e-03
1.10075e+04 6.39e-02 5.06e-03
1.68026e+04 3.43e-02 3.65e-03
2.18468e+04 5.66e-02 6.91e-03
2.75906e+04 5.16e-02 7.24e-03
3.43580e+04 2.06e-02 2.92e-03
4.03060e+04 4.35e-02 4.20e-03
4.61773e+04 3.19e-02 3.61e-03
5.20307e+04 2.07e-02 2.89e-03
5.63931e+04 2.23e-02 3.34e-03
The spectral analysis shows excess absorption above the Galactic
value (9e20 cm-2) with 18.8+2.9-6.1 with a photon index
Gamma = 1.52+0.16-0.15. Because we do not know the nature of this
X-ray transient source (it was not present in the ROSAT All-Sky
Survey) we encourage optical observers to derive a spectrum
to identify the source.
Due to the distance of 8' away from the BAT position we do not
consider this X-ray source an afterglow of GRB 060204C.
As discussed by Sakamoto et al (GCN 4679) BAT trigger 180274 is
most likely not a real GRB and probably a hard X-ray transient.
We have no further plan to re-observe the field of BAT trigger
180274.