GRB 071013
GCN Circular 6930
Subject
GRB 071013: 3rd TLS Epoch - constraints on variability
Date
2007-10-17T22:22:37Z (18 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, U. Laux & R. Filgas (TLS Tautenburg) report:
During a serendipitous opening in the cloud cover, we observed the field
of GRB 071013 (Marshall et al., GCN 6907) with the Tautenburg 1.34m
Schmidt telescope under very good conditions, obtaining 4 300 second
images in the Rc band at 4.2 days after the GRB, before clouds returned
and shut us down. We use the same comparison star as given in Kann,
Hoegner & Filgas (GCN 6917), and find the following magnitude of the
possible variable source discovered by Kornienko et al. (GCN 6925) in a
stacked image:
Date Mid-Time Rc dRc
17.78693 4.28046 19.584 0.023
Thus, the magnitude remains unchanged in comparison to the second epoch
(Kann et al., GCN 6926). Between 3.2 and 4.2 days, we rule out, at 3 sigma
confidence level, any additional source (e.g., a rising SN component)
brighter than R = 22.5.
We also analyse the Kornienko Candidate in the stacked image of our first
epoch (Kann, Hoegner & Filgas, GCN 6917). To summarize, from the three
stacked images, we derive the following magnitudes of the possible host
galaxy:
Date Mid-Time Exposure Rc dRc
13.79254 0.28608 13 x 600 19.565 0.009
16.75845 3.25198 6 x 300 19.583 0.015
17.78693 4.28046 4 x 300 19.584 0.023
If the slight magnitude difference between epoch 1 and epoch 2 would be
due to an additional source, it would have had R ~ 24 at 0.29 days.
Assuming the detection by Kornienko et al. is real, and the "host" has R =
19.583, the "host-corrected" magnitude of the Kornienko Candidate is R =
18.56. The decay slope is then found to be alpha ~ 2 between 0.024 and
0.286 days. This is steep but not completely unrealistic. We are thus
unable to rule out that the object found by Kornienko et al. may be a
superposed faint afterglow, although contemporary measurements (Xin et
al., GCN 6929) do not detect it. Since Swift seems to have not slewed at
all and no position more precise than the refined BAT error circle is
known (Palmer et al., GCN 6911), X-ray confirmation will probably not be
forthcoming.
This message may be cited.
GCN Circular 6929
Subject
GRB 071013: TNT optical data refined analysis
Date
2007-10-17T15:08:04Z (18 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 and W.K. Zheng on behalf of EAFON report:
We refined the TNT data obtained in Oct. 13 (GCN 6908)
the object observed by Kornienko et al. (GCN 6925) can
not be confirmedin our R band images that were observed
in the same period.Our data was taken under bad seeing ~4".
In combined 6*60s R band image taken bewteen 12:39:03 -
12:47:54 (UT), we could not see the object at the position
RA(J2000)=18:37:49.1 Dec(J2000)=+33:50:25(Kornienko et al., GCN 6925).
The source of USNO-B1.0 1238-0299614(RA(J2000)=18:37:48.84
Dec(J2000)= +33:50:26.7) was marginally detected in this combined
image at 2.5 sigma level, and no obvious new object around was detected
at the same sigma level. We examined images before
and after this period, also no obvious new object was detected.
Using the same comparison star at RA (J2000) = 18:38:05.67,
Dec (J2000) = +33:54:14.61 which has R2=17.22 (Kann et al.,
GCN 6917, GCN 6926),we estimate the USNO-B1.0 1238-0299614 star
had the following magnitude at the epoch of our observation (GCN 6908):
---------------------------------------------------
T_start(UT) T_stop(UT) Band Exptime Mag M_err
12:21:38 12:38:45 R 13*60s 19.3 0.3
12:39:03 12:47:54 R 6*60s 19.4 0.4
12:48:47 13:46:44 R 11*300s 19.7 0.2
---------------------------------------------------
We suggest the object reported in GCN6926 is the same star.
This message may be cited.
GCN Circular 6926
Subject
GRB 071013: TLS 2nd epoch - Kornienko candidate constant
Date
2007-10-16T19:51:44Z (18 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, C. Hoegner, U. Laux & R. Filgas (TLS Tautenburg) report:
We observed the field of GRB 071013 (Marshall et al., GCN 6907) with the
Tautenburg 1.34m Schmidt telescope under good conditions, obtaining 6 300
second images in the Rc band at 3.2 days after the GRB. We use the same
comparison star as given in Kann, Hoegner & Filgas (GCN 6917), and find
the following magnitudes of the possible variable source discovered by
Kornienko et al. (GCN 6925):
Date Mid-Time Rc dRc
13.74086 0.23439 19.537 0.027
13.75231 0.24584 19.506 0.028
13.76103 0.25456 19.634 0.040
13.76977 0.26330 19.566 0.032
13.77850 0.27203 19.704 0.036
13.78723 0.28076 19.629 0.038
13.79596 0.28950 19.683 0.045
13.80469 0.29822 19.593 0.044
13.81342 0.30695 19.589 0.038
13.82216 0.31569 19.635 0.028
13.83088 0.32441 19.598 0.044
13.83961 0.33314 19.572 0.040
13.84834 0.34187 19.762 0.054
Thus, we see no significant variability in the source over the span from
0.23 to 0.34 days after the GRB.
For the second epoch, we combine the 6 300 second images and find, using
the same comparison star:
Date Mid-Time Rc dRc
16.75845 3.25198 19.583 0.015
Thus, we also see no variability between 0.3 and 3.3 days after the GRB.
If this source is at low redshift and possibly associated with a
supernova, there is no evidence for it yet. Further photometric follow-up
and spectroscopy of the USNO/DSS source is encouraged.
This message may be cited.
GCN Circular 6925
Subject
GRB071013: optical observations
Date
2007-10-16T18:57:43Z (18 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
G. Kornienko, A. Erofeeva (UAFO), A. Pozanenko (IKI) on behalf of larger GRB
follow up collaboration report:
We observed the error box of GRB071013 (Marshall et al., GCN 6907) on
Oct.13 with SR-22 telescope of UAFO observatory. A set of 50 unfiltered
images of 60 s exposure was obtained starting (UT) 12:33:04. In images
between 12:39:04 - 12:49:04 we observed an object at the position RA(J2000)
= 18:37:49.1 Dec(J2000)= +33:50:25 with uncertainties of 3" in both
coordinates. The object is not visible before and after this time
(UT)12:39:04 - 12:49:04. The object is in refined BAT error circle (Palmer
et al., GCN 6911). Based on nearby USNO-A2.0 stars we estimate brightness of
the object as R~18.2.
The source of USNO-B1.0 1238-0299614 (RA(J2000)=18 37 48.84 Dec(J2000)=
+33 50 26.7) sits close (or coincides) to our object and it has R2=19.6.
The photometry of the source in deep TLS observation (Kann et al., GCN 6917)
is R=19.5 (Kann, private communication). If the USNO-B1.0 1238-0299614
source is a galaxy, then the afterglow may be masked of the galaxy in later
times. At this time we cannot confirm the nature of the found object and we
encourage to refine observations at the same period (Xin et al., GCN 6908).
The message may be cited.
GCN Circular 6917
Subject
GRB 071013: TLS Upper Limit
Date
2007-10-15T20:08:41Z (18 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, C. Hoegner & R. Filgas (TLS Tautenburg) report:
We observed the field of GRB 071013 (Marshall et al., GCN 6907) with the
Tautenburg 1.34m Schmidt telescope under good conditions, obtaining 13 600
second images in the Rc band. Within the revised BAT error circle (Palmer
et al., GCN 6911), we find no new sources in comparison to the DSS. We
note that our stacked image is much deeper than the DSS, and contains many
additional faint sources. More precise analysis awaits the publication of
a Swift XRT position.
Assuming the USNO B1.0 star at RA (J2000) = 18:38:05.67, Dec. (J2000) =
+33:54:14.61 to have R2=17.22, we derive the following magnitude limit for
regions not close to bright stars:
Date Mid-Time Rc limit (2 sigma)
13.79254 0.28608 23.0
This message may be cited.
GCN Circular 6913
Subject
GRB 071013: Optical observations
Date
2007-10-14T13:54:35Z (18 years ago)
From
Kuntal Mishra at ARIES,Nainital,India <kuntal@aries.ernet.in>
Rupak Roy, K. Misra and S. B. Pandey (ARIES, NainiTal, India, on behalf
of larger Indian GRB collaboration)
We imaged the field of Swift GRB 071013 (Marshall, F. E. et al. GCN6907)
with the 1.04m telescope at NainiTal ~ 5 hours after the burst.
Observations were performed in R and I bands in poor sky conditions.
No afterglow candidate was found in our combined images within the error
region of BAT.
The 3-sigma limit derived form USNO-B1.0 is I ~20 mag.
This message may be cited.
GCN Circular 6912
Subject
GRB 071013: optical observations at NOT
Date
2007-10-13T23:30:48Z (18 years ago)
From
Daniele Malesani at Niels Bohr Inst,Dark Cosmology Center <malesani@astro.ku.dk>
D. Malesani, (DARK), J. Gorosabel (IAA-CSIC), P. Jakobsson (Univ.
Hertfordshire), J.P.U. Fynbo (DARK), J. Niemela, C. Villforth (NOT)
report on behalf of larger collaboration:
We observed the field of GRB 071013 (Marshall et al., GCN 6907) using
the Nordic Optical Telescope. Observations were carried out in the R and
I filters, with mean integration epochs on Oct 13.867 and 13.894 UT
(8.65 and 9.30 hr after the GRB).
By comparison with the DSS, we do not detect any obvious candidate
afterglow down to the DSS limiting magnitude R~20.5.
Further observations are planned.
[GCN OPS NOTE(14oct07): Per author's request, the Fynbo affiliation
was changed from "NOT" to "DARK".]
GCN Circular 6911
Subject
GRB 071013, Swift-BAT refined analysis
Date
2007-10-13T17:24:19Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
D. Palmer (LANL), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC),
E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA),
C. Markwardt (GSFC/UMD), F. Marshall (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-119 to T+183 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 071013 (trigger #294120)
(Marshall, et al., GCN Circ. 6907). The BAT ground-calculated position is
RA, Dec = 279.501, 33.846 deg which is
RA(J2000) = 18h 38m 0.3s
Dec(J2000) = 33d 50' 46"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 70%.
The mask-weighted light curve shows a single peak starting at ~T-5 sec,
peaking at ~T+5sec, and ending at ~T+30 sec. T90 (15-350 keV) is 26 +- 1 sec
(estimated error including systematics).
The time-averaged spectrum from T-5.9 to T+23.4 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.60 +- 0.36. The fluence in the 15-150 keV band is 3.2 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+3.69 sec in the 15-150 keV band
is 0.4 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
GCN Circular 6910
Subject
GRB071013: optical limit
Date
2007-10-13T16:47:58Z (18 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Klunko(ISTP), A. Marchenkov (ISTP), A. Pozanenko (IKI) on behalf of
larger GRB follow up collaboration report:
We observed the error box of GRB071013 (Marshall et al., GCN 6907) in
R-band on Oct.13 with 1.5m telescope of Sayan observatory. A set of images
of 120 s exposure was obtained starting (UT) 13:20:27. No obvious optical
candidate is found within BAT error circle in the first image (UT) 13:20:27
in comparison with DSS2. Based on USNO A2.0 we estimate limiting magnitude
of the first image as R=19.2.
The message may be cited.
GCN Circular 6907
Subject
GRB 071013: Swift detection of a burst
Date
2007-10-13T12:49:52Z (18 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
G. Cusumano (INAF-IASFPA), N. Gehrels (NASA/GSFC),
J. A. Kennea (PSU), V. La Parola (INAF-IASFPA),
V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD),
P. T. O'Brien (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (Univ. Bicocca & INAF-OAB),
G. Sato (GSFC/ISAS), B. Sbarufatti (INAF-IASFPA),
T. N. Ukwatta (GSFC/GWU) and H. Ziaeepour (UCL-MSSL) report on behalf
of the Swift Team:
At 12:09:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 071013 (trigger=294120). Swift did not execute an immediate slew.
The BAT on-board calculated location is
RA, Dec 279.525, +33.857 which is
RA(J2000) = 18h 38m 06s
Dec(J2000) = +33d 51' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a peak ~40 sec duration.
The peak count rate was ~800 counts/sec (15-350 keV), at ~2 sec after the trigger.
There are no XRT or UVOT data products because auto-slewing to new bursts
is disabled while in gyro-calibration mode.
Burst Advocate for this burst is F. E. Marshall (marshall 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.)