GRB 071018
GCN Circular 7009
Subject
GRB 071018: Revised BAT position
Date
2007-10-26T22:30:30Z (19 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
H.A. Krimm (CRESST/GSFC/USRA), J. R. Cummings (CRESST/GSFC/UMBC),
A.P. Beardmore
(U. Leicester)report on behalf of the Swift-BAT team:
In further analysis of GRB 071018 (Krimm et al, GCN 6932), when
we use a time interval of T+20 to T+470 and an energy interval
of 14 to 100 keV, we get a higher significance detection with a
position:
RA, dec = 164.685, +53.822 deg, which is
RA(J2000) = 10h 58m 44.4s
dec(J2000) = 53d 49' 18"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
We note that this new error circle is inconsistent with any of the
sources found in
the XRT (Beardmore et al, GCN 6943) or optical (Xin et al, GCN 6936). However,
XRT source #5 (Krimm et al, GCN Report 96.1) at RA, dec = 164.7216,
+53.8140 deg,
is within the new error circle.
GCN Circular 6965
Subject
GRB071018: 2nd epoch obsevations of Xinglong TNT
Date
2007-10-21T18:24:51Z (19 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, M. Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng,
J. Wang, Y. Urata and W.K. Zheng on behalf of EAFON report:
We observed the field of GRB071018 (Krim et al. GCN 6932) with the TNT 0.8m
telescope at Xinglong Observatory for the 2nd epoch, Observation was started
from 19:12:25 UT, 19th Oct. 1.494 days after the burst. A series of R-band
images were obtained. In our 14*600s combined images we can still find the
two sources of our last observation (Xin et al. GCN 6936).
The estimated bringhtness of the source #1 and #2 (Xin et al. GCN6936)
derieved from USNO-B1.0 R2 magnitude were R=20.67+-0.318 and R=20.72+-0.36
respectively. The magnitude of source #1 was consistent with the value
reported by SARA (Updike et al. GCN 6944) and Mercator (Alberto
Castro-Tirado, GCN6947). but bringter than the value of our last observation
(Xin et al. GCN6936), So the source #1 only maybe a avariable source as
reported (Adria, GCN 6944), and the source $2 also might not be the OT of the
burst.
At the locations of the XRT error circles of source 1 and source 2 (GCN 6943,
Beardmore et al.), We found no new optical source to the 3sigma limit
magnitude R=21.2 .
We also checked the combined image (Xin et al. GCN6936) obtained on 18th Oct,
No new source was found at the location of XRT source 2 to 3-sigma limit
magnitude R=21.5. The location of XRT source 1 was outside the field of view
of the combined image.
This massage may be cited.
GCN Circular 6947
Subject
GRB 071018: Mercator Telescope optical observations
Date
2007-10-19T22:14:41Z (19 years ago)
Edited On
2024-11-18T09:44:59Z (2 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
J. Gorosabel (IAA-CSIC Granada), A. de Ugarte Postigo (ESO Santiago), M.
Jelínek (IAA-CSIC), M. Vuckovic (Katholieke Universiteit Leuven), E.
Rubio-Herrera, P. van Ham, F. van Weerdenburg, P. van Oers (Univ. of
Amsterdam) and A. J. Castro-Tirado (IAA-CSIC) report:
"Following the detection of GRB 071018 by SWIFT (Krim et al. GCNC 6932)
we have obtained R & I-band observations with the 1.2m Mercator
telescope at Observatorio del Roque de los Muchachos in La Palma. The
frames were obtained starting on 19.2916 Oct (i.e. 22.4 hr after the BAT
trigger). The result of the Mercator Telescope follow-up observation,
referred to the two optical sources reported by Lin et al. (GCNC 6936)
and the two XRT sources reported by Beardmore et al. (GCNC 6943) is the
following one:
The optical source # 1 at RA(J2000) = 10:58:11.3 Dec(J2000)= +53:50:56 is
well detected in our R & I-band frames with R = 20.6 +/- 0.4 based on
the photometry given in the USNO-B1.0 catalogue. This is consistent with
the value reported by SARA (Updike et al. GCNC 6944) about 3 hours
later. We note that there is no "quiescent" counterpart to this object
in the SDSS but the lack of an X-ray counterpart argues against this
variable object being the optical afterglow.
The location of the optical source # 2 at RA(J2000)= 10:58:21.459
Dec(J2000)= +53:51:09.85 is covered in our images and we do not see any
object at this position with a limiting magnitude of R ~ 22.0 (besides
the one present in the SDSS).
The location of the XRT source # 1 at RA(J2000) = 10 58 02.99 Dec(J2000)
= +53 49 21.9 is covered in our images and we do not see any object at
this position with a limiting magnitude of R ~ 22.0.
The XRT source # 2, outside the refined BAT error box (Sato et al. GCNC
6933), is also outside the field of view of the Mercator frames.
Further observations are encouraged."
GCN Circular 6944
Subject
GRB 071018: SARA observations
Date
2007-10-19T19:28:57Z (19 years ago)
From
Adria C. Updike at Clemson U <aupdike@clemson.edu>
Adria C. Updike, Brian Donehew, Paul Jay Searcy, Ernest Garrison, and
Dieter H. Hartmann report (on behalf of the Clemson GRB Follow-Up Team):
We observed the field of GRB 071018 (GCN 6932, Krimm et al.) beginning
1.05 days after the trigger under good weather conditions. We obtained
69 minutes of R-band images at high airmass.
Upon comparison to the sources identified by Xin et al. (GCN 6936), we
find a magnitude of 20.5 � 0.15 for OT candidate #1. We note that this
is brighter than the magnitude reported by Xin et al. half a day
earlier, so this may indeed be a variable source.
We also note a source in SDSS images at the location of GCN 6936 OT
candidate #2.
At the locations of the XRT error circles (GCN 6943, Beardmore et al.),
we detect no new sources down to a limiting magnitude of 20.8 in the R
band.
Calibration to the USNO B1.0 catalog was done relative to 10 field stars.
We would like to thank Liping Xin for providing a finder chart and
additional information on their observations. We also acknowledge the
help of Kenneth Rumstay (Valdosta U).
This message may be cited.
GCN Circular 6943
Subject
GRB 071018: Swift-XRT observation
Date
2007-10-19T16:28:50Z (19 years ago)
From
Andy Beardmore at U Leicester <apb@star.le.ac.uk>
A.P. Beardmore, K.L. Page, P.A. Evans, R.L.C. Starling, J.P. Osborne
(U. Leicester) and H.A Krimm (GSFC/USRA) report on behalf of the
Swift-XRT team:
The Swift-XRT began observing the field of the BAT GRB 071018
(trigger #294645) at 2007-10-19T00:36, 57 ks after the trigger.
A photon counting mode image containing an exposure time of 4.0 ks
reveals two faint uncatalogued sources:
Source 1 is at RA, Dec (J2000) = 164.51244, 53.82275, which is
RA(J2000) = 10 58 02.99
Dec(J2000) = +53 49 21.9
with an estimated uncertainty of 6.4 arcsec (radius, 90 percent
confidence). This is 4.25 arcmin away from the refined BAT position
of Sato et al. (GCN 6933), but outside the quoted BAT 2.7 arcmin
90 percent error circle. Its estimated count rate is (3.2+/-0.9)e-3
count s^-1.
Source 2 is at RA, Dec (J2000) = 164.58083, 53.82383, which is
RA(J2000) = 10 58 19.40
Dec(J2000) = +53 49 25.8
with an estimated uncertainty of 7.9 arcsec (radius, 90 percent
confidence). This is 2.37 arcmin away from the refined BAT position
and within its error circle. Its estimated count rate is (2.0+/-0.8)e-3
count s^-1.
At this stage we cannot tell whether either source is fading and
therefore associated with the GRB. Further observations are
planned by Swift over the weekend.
This circular is an official product of the Swift-XRT team.
GCN Circular 6941
Subject
VLA radio observation of GRB 071018
Date
2007-10-19T16:07:53Z (19 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
P. Chandra (UVA/NRAO) and D. A. Frail (NRAO) report on behalf of the
Caltech-NRAO-Carnegie GRB Collaboration:
"We observed the Swift burst GRB 0701018 (GCN#6932) using the VLA
at a frequency of 8.46 GHz and starting at 12.38 UT on Oct 19, 2007. We do
not detect any radio emission within BAT error box (GCN#6933).
We also do not detect any radio emission at the positions of the two new
sources
found by the TNT 0.8m telescope at Xinglong Observatory (GCN#6936).
The map noise is 31 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 6940
Subject
GRB071018: Correction to the GCN 6936
Date
2007-10-19T00:42:19Z (19 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, M. Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng,
X.F Wang and W.K. Zheng on behalf of EAFON report:
We are sorry to make you in trouble !
In the GCN 6936, what we observed
was GRB 071018 but not GRB 071013
GCN Circular 6939
Subject
GRB071018: Correction to the GCN 6936
Date
2007-10-19T00:42:19Z (19 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, M. Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng, X.F Wang
and W.K. Zheng on behalf of EAFON report:
We are sorry to make you in trouble !
In the GCN 6936, what we observed was
GRB 071018 but not GRB 071013
GCN Circular 6938
Subject
GRB071018: Correction to the GCN 6936
Date
2007-10-19T00:39:38Z (19 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, M. Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng, X.F Wang
and W.K. Zheng on behalf of EAFON report:
We are sorry to make you in trouble !
It was GRB 071018 but not GRB 071013
GCN Circular 6937
Subject
GRB071018: Correction to the title of the GCN 6936
Date
2007-10-19T00:05:49Z (19 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
I am sorry to correct the title of the GCN 6936
to be the GRB 071018: Possible OT from Xinglong TNT Observation
GCN Circular 6936
Subject
GRB 071018: Possible OT from Xinglong TNT observation
Date
2007-10-18T23:55:33Z (19 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, M. Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng, X.F Wang
and W.K. Zheng on behalf of EAFON report:
We have imaged the field of GRB 071018 (Krimm et al. GCN 6932, Sato et al. GCN 6933)
with the TNT 0.8m telescope at Xinglong Observatory started
from 19:05:11.203 UT, about 0.435 days after the trager of the
burst. A set of 15*600s R-band images were obtained.
In our 15*600s combined image, we found two clear new objects
at the position RA(J2000) = 10;58:11.3 Dec(J2000)=+53:50:56 and
RA(J2000)= 10:58:21.459 Dec(J2000)=+53:51:09.85 within the error
region of the BAT (GCN 6933), based on the USNO-B1.0
with uncertainties of 3" in both coordinates, respectively.
After psf photometry, we estimated that the magnitudes of
the new two objects were about 21.49+-0.220, 21.46+-0.227 reletive to
USNO-B1.0 stars, respectively, with the mean time 0.486 days after
the burst.
We could not confirm that which one of the two new objects was the OT
of the burst or maybe thay were not al all but one of them
was possible to be.
We suggest new observations will be going.
More detailed analysis is on going!
The message my be cited
[GCN OPS NOTE(19oct07): Per author's request, The Subject-line
was changed from "20070521" to "071018". The first line was changed
from "071013 (GCN 6932, GCN 6933)" to
"071018 (Krimm et al. GCN 6932, Sato et al. GCN 6933)".]
GCN Circular 6933
Subject
GRB 071018, Swift-BAT refined analysis
Date
2007-10-18T20:35:53Z (19 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
G. Sato (GSFC/ISAS), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL),
A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+844 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 071018 (trigger #294645)
(Krimm, et al., GCN Circ. 69342). The BAT ground-calculated position is
RA, Dec = 164.617, 53.857 deg which is
RA(J2000) = 10h 58m 28.0s
Dec(J2000) = 53d 51' 26"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 97%.
We confirm that this event has the characteristics of a true gamma-ray burst.
The mask-weighted light curve shows an enlongated multi-peaked structure.
The burst location came into the BAT field of view at T-70 sec.and there was
an initial peak at T-50 sec, followed by low-level emission from T+20 to T+80,
followed by the main emission in several peaks from T+120 sec to T+420 sec.
There is also possible emission at later times (~T+600 and ~T+800), although
statistics are poorer for this late time since the spacecraft slewed to a new
target, moving the burst nearer the edge of the field of view.
T90 (15-350 keV) is 376.0 +- 20 sec (estimated error including systematics).
The time-averaged spectrum from T+113.1 to T+417.7 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.63 +- 0.26. The fluence in the 15-150 keV band is 1.0 +- 0.2 x
10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+124.18 sec in the 15-150 keV band
is 0.2 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
This burst has several characteristics which are typical of high
redshift bursts. Its duration is long (T90 = 376 sec) with relatively
few (three) significant peaks. The 1-s peak flux is < 1.0 ph/cm2/s
and the power-law photon index (1.65) is < 2.
GCN Circular 6932
Subject
GRB 071018?: Swift detection of a possible burst
Date
2007-10-18T09:04:33Z (19 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC),
P. T. O'Brien (U Leicester), D. M. Palmer (LANL) and
B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team:
At 08:37:41 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 071018(?) (trigger=294645).
The BAT on-board calculated location is
RA, Dec 164.676, +53.830 which is
RA(J2000) = 10h 58m 42s
Dec(J2000) = +53d 49' 49"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). This was a 320-sec long image trigger, so the
TDRSS lightcurve does not show any significant signal (as is typical).
This location is well off the Galactic plane and does not mach any known
sources in SIMBAD. Given that it is a long image trigger, this was
automatically classifed as a transient instead of a GRB. We will need
the full data set to determine if this is a burst or transient.
Because Swift is in the process of returning to normal operations,
automatic slewing to GRBs is currently disabled outside of
business hours (US EDT). Therefore, there
are no prompt XRT or UVOT observations of this burst.
Burst Advocate for this burst is H. A. Krimm (krimm 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.)