GRB 071020
GCN Circular 7146
Subject
GRB071020: optical observations
Date
2007-12-11T22:46:19Z (18 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Sergeev, V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We observed the optical afterglow (Schaefer et al. GCN 6948) of GRB071020
(Tueller et al. GCN 6954) in I and B bands on Oct.10-11 between (UT)
23:51:34 - 01:11:47 with AZT-8 telescope of CrAO. We detected the afterglow
in I-band, and not detected it in B-band. Based on SDSS stars (Cool et al.
GCN 6950) RA=119.66618, Dec=32.84706; RA=119.68899, Dec=32.84803;
RA=119.66782, Dec=32.85465 we estimated brightness of the optical
afterglow on a stacked images:
T0+, Exposure, Filter, mag., UL
(mid time)
0.730 d 12x90 s I 20.5 +/-0.3 20.5
0.728 d 12x180 s B n/d 21.0
The message may be cited.
GCN Circular 7026
Subject
GRB 071020: MITSuME Akeno optical observations
Date
2007-10-31T11:38:14Z (18 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
T. Ishimura, Y. Yatsu, T. Shimokawabe, N. Kawai (Tokyo Tech) and
M. Yoshida (NAOJ) report on behalf of the MITSuME collaboration:
We observed the field of GRB 071020 (Holland et al. , GCN6949) with
the 3-color 50cm MITSuME Telescope at Akeno, Japan from UT 16:21 to
UT 19:53 on Oct. 20, 9.3 hours after the trigger.
In the co-added images of Ic and Rc bands, we detected the optical
afterglow reported by Schaefer et al. (GCN 6948). Photometric
calibration was done using the USNO-B1.0 (Ic-band) and NOMAD (g'- and
Rc-bands) catalogs. The results are following:
Filter start end Exposure Mag
------------------------------------------------------
g' 16:21:13 19:53:55 149 x 60s >21.1 (3 sigma upper limit)
Rc 16:21:13 19:53:55 149 x 60s 21.2 +/- 0.3
Ic 16:21:13 19:53:55 149 x 60s 19.8 +/- 0.3
------------------------------------------------------
GCN Circular 7006
Subject
GRB071020, optical upper limit
Date
2007-10-26T12:37:21Z (18 years ago)
From
Eri Sonoda at U of Miyazaki/Japan <sonoda@astro.miyazaki-u.ac.jp>
R. Hara, E.Sonoda, H.hayasi, N.Ohmori, K.Kono H. Tanaka, M.Yamauchi
(University of Miyazaki)
We have observed the field covering the error circle of
GRB071020 (GCN 6954, J. Tueller et al.) with
the unfiltered CCD camera on the 30-cm telescope at
University of Miyazaki.
The observation was started 15:29:35 UT, ~507 min.
after the Swift trigger time.
We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog,there is no new source
at the reported position (GCN 6948, B.E.Schaefer et al.
GCN 6949, S.T.Holland et al. GCN 6978, P. Chandra et al.)
the upper limits are as follows:
--------------------------------------------------------------
Start(UT) End(UT) Num. of frames Limit (mag.)
--------------------------------------------------------------
15:31:27 15:31:57 1 ~16.5
15:31:27 16:24:39 20 ~17.0
---------------------------------------------------------------
GCN Circular 6984
Subject
GRB 071020: BTA spectroscopy
Date
2007-10-24T15:00:41Z (18 years ago)
Edited On
2024-11-18T10:10:49Z (a year 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>
T. A. Fatkhullin, V. V. Sokolov (SAO-RAS Nizhnij Arkhyz), S. Guziy
(Nikolaev St. Univ.), A. de Ugarte Postigo (ESO Santiago), D.
Pérez-Ramírez (Univ. de Jaén and U. Leicester), J. Gorosabel, M. Jelínek
and A. J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger
collaboration, report:
"Following the detection of GRB 071020 by SWIFT (Holland et al. GCN
Circ. 6949) we obtained optical spectroscopy with the 6.0m BTA
telescope (+SCORPIO) of the SAO-RAS. In spite of poor weather
conditions (dense cirrus) we managed to get 4 x 1200s spectra of the
proposed optical afterglow (Schaefer et al. GCN Circ. 6948). The data
were taken on Oct 21.05 U.T. (i.e. 18 hr after the event), with the VPHG
400 grism (range 3700-9000 A).
We identify absorption lines from Fe II (2344, 2586 and 2600) and
possibly C IV (1548-1550) and Fe II (1608), at z = 2.142 ± 0.002. This
confirms the lower limit to the GRB 071020 redshift derived from VLT
spectroscopy (Jakobsson et al., GCN Circ. 6952). Moreover, we do not
see any flux drop in the OA spectrum around 4300 A as the VLT spectrum
may suggest. However, there are indications of a flux drop at ~3870A but
the low S/N ratio in this range prevents us to draw any further
conclusion."
This message can be quoted.
GCN Circular 6981
Subject
Optical observations of GRB 071020
Date
2007-10-23T11:25:46Z (18 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Veli-Pekka Hentunen (Taurus Hill Observatory, Varkaus, Finland) reports to
the AAVSO International High Energy Network the following optical
observations of GRB071020 (GCN #6949, Holland et al.):
Markku Nissinen, Henri Taino and Veli-Pekka Hentunen report the detection
of the optical afterglow of GRB 071020 (Holland et al., GCN 6949; Schaefer
et al., GCN 6948