GRB 080810
GCN Circular 8080
Subject
GRB 080810: Swift detection of a burst with a bright optical afterglow
Date
2008-08-10T13:31:39Z (17 years ago)
From
David Burrows at PSU/Swift <dxb15@psu.edu>
K. L. Page (U Leicester), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
P. A. Evans (U Leicester), C. Guidorzi (INAF-OAB),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
N. P. M. Kuin (MSSL), J. Mao (INAF-OAB), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU),
R. L. C. Starling (U Leicester) and T. N. Ukwatta (GSFC/GWU) report
on behalf of the Swift Team:
At 13:10:12 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 080810 (trigger=319584). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 356.779, +0.320 which is
RA(J2000) = 23h 47m 07s
Dec(J2000) = +00d 19' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multiple-peaked
structure with a duration of about 140 sec, including a peak during the
time of the XRT/UVOT observations. The peak count rate
was ~3000 counts/sec (15-350 keV), at ~22 sec after the trigger.
The XRT began observing the field at 13:11:28.3 UT, 76.0 seconds after
the BAT trigger. XRT found a bright, flaring, uncatalogued X-ray source
located at RA, Dec 356.7936, +0.3188 which is equivalent to:
RA(J2000) = 23h 47m 10.4s
Dec(J2000) = +00d 19' 07.6"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 52 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
UVOT took a finding chart exposure of nominal 100 seconds with the White
(160-650 nm) filter starting 88 seconds after the BAT trigger. There is a
bright candidate afterglow in the list of sources generated on-board at
RA(J2000) = 23:47:10.5 = 356.79375
DEC(J2000) = +00:19:10 = +0.31944
with a 1-sigma error radius of about 1.0 arc sec. The estimated white
magnitude is 14.7 with a 1-sigma error of about 0.5 mag. No correction
has been made for a Galactic extinction corresponding to a reddening of
0.03 mag along the line of sight.
We note the presence of the galaxy J234710.47+001906.0
about 1.7 arcsec from the XRT position.
Burst Advocate for this burst is K. L. Page (kpa AT star.le.ac.uk).
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.)
GCN Circular 8081
Subject
GRB 080810 : optical observation with KANATA
Date
2008-08-10T13:51:42Z (17 years ago)
From
Akira Arai at Hiroshima U <arai-akira@hiroshima-u.ac.jp>
Y. Ikejiri, M. Uemura, T. Ohsugi, K. Kawabata, A. Arai, M. Yamanaka, and K. Sakimoto (Hiroshima Univ.),
report on behalf of the KANATA GRB team:
We performed optical-NIR observations of the field of
GRB 080810 (GCN Circ. 8080) with TRISPEC attached to
the "KANATA" 1.5-m telescope.
We confirmed a very bright, fading object at the position of the optical
afterglow detected with UVOT.
Our preliminary results are below:
time(UT) mag. exposure_time
Aug. 2008 (sec)
10.553258 13.7 $B!^(B 0.1 V 33sec * 1
Comparison star:
23:46:58.51 +00:18:30.2 V=14.07 (NOMAD)
Further observation and analysis are ongoing.
GCN Circular 8082
Subject
GRB 080810, Swift-BAT refined analysis
Date
2008-08-10T16:20:08Z (17 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD),
K. L. Page (U Leicester), D. Palmer (LANL), G. Sato (ISAS),
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+381 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 080810 (trigger #319584)
(Page, et al., GCN Circ. 8080). The BAT ground-calculated position is
RA, Dec = 356.783, 0.310 deg which is
RA(J2000) = 23h 47m 08.0s
Dec(J2000) = +00d 18' 35.1"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 68%.
The mask-weighted light curve shows a cluster of overlapping peaks starting
at ~T-20, the tallest at T+25 sec, and ending at ~T+120 sec.
T90 (15-350 keV) is 106 +- 5 sec (estimated error including systematics).
The time-averaged spectrum from T-21.2 to T+111.4 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.34 +- 0.06. The fluence in the 15-150 keV band is 4.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+24.68 sec in the 15-150 keV band
is 2.0 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/319584/BA/
GCN Circular 8083
Subject
GRB 080810: Keck/HIRES Spectroscopy
Date
2008-08-10T17:51:26Z (17 years ago)
From
Jason Prochaska at UCO/Lick Obs <xavier@ucolick.org>
J.X. Prochaska (UCSC), D. Perley (UCB),
A. Howard (UCB), H.-W. Chen (Chicago),
G. Marcy (UCB), D. Fischer (SFSU), and
C. Wilburn (Keck) report on behalf of GRAASP:
"We observed the afterglow of GRB 080810 with the Keck/HIRES
echelle spectrometer for a series of 1000s exposures starting
at UT 13:47:50 under good conditions. A quick analysis of the
2D images reveals a Lyman limit system at ~3975Ang.
We tentatively associate this feature with the host galaxy
of GRB 080810 and estimate a redshift z_GRB = 3.35.
Further analysis is in progress."
This GCN may be cited.
GCN Circular 8084
Subject
GRB 080810: ROTSE-III Prompt Detection of Optical Counterpart
Date
2008-08-10T18:29:37Z (17 years ago)
From
Eli Rykoff at UCSB <erykoff@physics.ucsb.edu>
E.S. Rykoff (UCSB), reports on behalf of the ROTSE collaboration:
ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded
to GRB 080810 (Swift trigger 319584, GCN 8080, Page et al.). The first
image was at 13:10:47.6 UT, 35.3 s after the burst (21.6 s after the
GCN notice time), contemporaneous with the gamma-ray emission (GCN
8082, Sakamoto et al.). We took 10 5s exposures, 10 20s exposures,
and 137 60s exposures under variable conditions. The unfiltered
images are calibrated relative to USNO B1.0. We detect a 12.8
magnitude, variable source with coordinates:
23:47:10.5 +00:19:11.5 (J2000) (uncertainty of 1" or better)
start UT mag mlim(of image)
----------------------------------
13:11:16.7 12.8 16.5
The position is consistent with the XRT and UVOT positions reported in
GCN 8080.
Our prompt detection shows the afterglow initially rising from 13.7
mag (38s post-burst) to a peak of 12.8 mag (67s post-burst). This is
followed by a shallow decay from ~67s to ~230s (decay index
alpha=-0.15+/-0.05), and a break to a steeper decay from ~230s to
~6000s post-burst (decay index alpha=-1.13+/-0.02). Preliminary
analysis does not show any significant deviations from this smooth
evolution.
A jpeg image is available at
http://www.rotse.net/images/gsb319584_3a02_img.jpg
The object in question is marked with yellow and blue circles.
GCN Circular 8085
Subject
GRB 080810: KANATA optical-NIR observation, update
Date
2008-08-10T19:35:44Z (17 years ago)
From
Makoto Uemura at Hiroshima U <uemuram@hiroshima-u.ac.jp>
M. Uemura, M. Yamanaka, Y. Ikejiri, K. Sakimoto, T. Ohsugi,
K.S. Kawabata, and A. Arai, report on behalf of the KANATA GRB team:
We continue the observation of GRB 080810 with the KANATA 1.5-m
telescope. We obtained V, J, and Ks-band images of the field
of the afterglow using TRISPEC.
The latest observation shows:
time(UT) mag. err exposure time
Aug. 2008
10.78444 18.92V 0.05 123sec * 10
10.78479 17.53J 0.31 72sec * 10
The light curve we obtained can be described with a simple
power-law decay between 420 and 20000 sec after the GRB trigger,
without an apparent break.
The power-law index is calculated to be 1.21+/-0.02.
The index is slightly, but significantly larger than that reported
in GCN 8084, implying a possible break around the very early
or very late phase of our observation period.
Further monitoring is encouraged.
GCN Circular 8086
Subject
GRB 080810: Enhanced Swift-XRT position
Date
2008-08-10T22:50:44Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1614 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 080810, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 356.79418, +0.32000 which is equivalent
to:
RA (J2000): 23h 47m 10.60s
Dec (J2000): +00d 19' 12.0"
with an uncertainty of 1.4 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position
can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is
described by Goad et al. (2007, A&A, 476, 1401
http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an
extension of this method.
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 8087
Subject
GRB 080810: Swift-XRT Team refined analysis
Date
2008-08-10T23:53:16Z (17 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed the first four orbits of the XRT data obtained for GRB
080810 (Page et al., GCN Circ. 8080). The first orbit (376 s) was taken
entirely in Windowed Timing (WT) mode, followed by 2.8 of Photon Counting
(PC) data. The UVOT-enhanced position was given by Evans et al. in GCN
Circ. 8086.
The WT data show a number of flares, with the strongest peaking around 107
and 209 s after the trigger; the first of these is also visible in the BAT
data. The PC data in later orbits can be modelled with a single power-law
decay, with alpha = 1.20 +0.12/-0.11.
There is strong spectral evolution throughout the first orbit, as is
typical for flaring activity. A spectrum extracted from the PC mode data
(3.8-12.1 ks after the trigger) can be fitted with a power-law of Gamma =
1.98 +/- 0.06, absorbed by the Galactic column in this direction of
3.28x10^20 cm^-2. The observed (unabsorbed) flux over this time is 1.99
(2.20) x 10^-11 erg cm^-2 s^-1.
If the decay continues with alpha = 1.2, the predicted count-rate at 24
hours is 0.02 count s^-1, corresponding to an observed (unabsorbed) flux
of 8.5 (9.4) x 10^-13 erg cm^-2 s^-1.
This is an official product of the Swift-XRT team.
GCN Circular 8088
Subject
GRB 080810: RTT150 optical observations
Date
2008-08-11T06:49:28Z (17 years ago)
From
Rodion Burenin at IKI, Moscow <rodion@hea.iki.rssi.ru>
R. Burenin (IKI), I. Khamitov (TUG), A. Galeev, I. Bikmaev,
N. Sakhibullin (KSU/AST), M. Pavlinsky, R. Sunyaev (IKI),
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
We observed the GRB 080810 afterglow with Russian-Turkish 1.5-m telescope
(RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey). We made a set
of exposures in BVRI between 8.3 and 12.6 hours after the burst. During our
observations the OT faded from 19.1 to 19.5 in R (USNO-B1.0 calibrated).
We also obtained a set of low resolution spectra using TFOSC
spectrometer. We detected Ly and other absorption lines and confirm the
redshift z=3.35 measured by Prochaska et al. (GCN 8083). Further analysis is
ongoing.
GCN Circular 8089
Subject
GRB 080810: Observations from NOT
Date
2008-08-11T07:15:29Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (ESO), C.C. Thoene, J.P.U. Fynbo,
J. Hjorth (DARK/NBI), P. Jakobsson (U. Hertfordshire),
Z. Banhidi (NOT, IAC), F. Grundahl, T. Arentoft (U. of Aarhus)
report on behalf of a larger collaboration:
We have observed the afterglow of GRB 080810 (Page et al.
GCN 8080) from the Nordic Optical Telescope (NOT, Roque de los
Muchachos Observatory, La Palma, Spain) using ALFOSC. The
observations started on 10.9899 Aug (10.59 hours after the burst),
when we measure an R-band magnitude of 19.1+/-0.2 (based on
USNO-1B photometry). This value is in agreement with the slope
decay measured by Rykoff (GCN 8084) implying that no break has
been produced between both observations. This is also consistent
with the magnitudes reported by Burenin et al. (GCN 8088). We
obtained the following coordinates for the afterglow (J2000+/-0.5"):
R.A.: 23:47:10.51
Dec.: +00:19:11.3
This value is slightly off from the value provided by UVOT (Page et
al. GCN 8080) but fully consistent with the one given by Rykoff
(GCN 8084).
We also obtained spectroscopic observations of the afterglow, where
we clearly detect Ly-alpha absorption, a flux drop blueward of the
Lyman break as well as other absorption lines, including the CIV/CIV
doublet at a redshift of z~3.35, in agreement to what was reported by
Prochaska et al. (GCN 8083) and Burenin et al. (GCN 8088).
GCN Circular 8090
Subject
GRB 080810: OSN follow-up
Date
2008-08-11T08:12:32Z (17 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (ESO), F. Aceituno, A.J. Castro-Tirado
(IAA-CSIC) report on behalf of a larger collaboration:
We have observed the field of GRB 080810 (Page et al.
GCN 8080) with the 1.5m OSN telescope at Sierra Nevada
Observatory (Granada, Spain), covering the range between
11.93 and 15.11 hours after the burst in B, V, R and I bands.
We observe a continuous decay following a slope of
alpha = -1.11+/-0.02, consistent with the slope provided by
Rykoff et al. (GCN 8084). Preliminary analysis shows the
following magnitudes in an intermediate epoch as compared
to reference stars derived from the SDSS.
t-t0(h) Filter Mag
13.82 B 21.4 +/- 0.3
13.62 V 20.2 +/- 0.2
13.85 R 19.5 +/- 0.2
13.25 I 19.2 +/- 0.2
GCN Circular 8091
Subject
GRB 080810: Kanazawa optical observation
Date
2008-08-11T08:16:50Z (17 years ago)
From
Daisuke Yonetoku at Kanazawa U <gcn@astro.s.kanazawa-u.ac.jp>
Y.Okuma, H.Fujimoto, T.Nashimoto, A.Wada, D.Yonetoku, T. Murakami,
report on behalf of the Kanazawa GRB team:
We have imaged the field of GRB 080810 (Page et al. GCN 8080)
in R-band with 0.4m telescope at Kanazawa Japan.
We obtained the first image at one and half hours after
the Swift trigger. We confirmed the bright optical counter
part reported by Page et al. (GCN 8080), Ikejiri et al. (GCN 8081),
and so on. Compared with the USNO-A2.0 catalog, the source
magnitude is determined about 16.5 +/- 0.2 mag with 30 seconds
exposure time from the begining of this observation.
Further analysis is in progress.
GCN Circular 8092
Subject
GRB 080810: D50 optical observation
Date
2008-08-11T10:14:35Z (17 years ago)
From
Matus Kocka at Monteboo Obs,Masaryk U,Brno <koci@astronom.sk>
M. Kocka (kocka@sunkl.asu.cas.cz), M. Nekola, J. Strobl, R. Hudec, C.
Polasek (AsU CAS - Ondrejov),
M. Jelinek, P. Kubanek (IAA-CSIC - Granada),
F. Munz (IASF/INAF - Bologna)
The 0.5m D50 telescope in the Ondrejov Observatory of the Astronomical
Institute of the Academy of Sciences of the Czech Republic, observed GRB
080810.Observation started at 22:26:41 UT (~9.4 hours after SWIFT
detection).
After 80x20 sec exposure we detected optical counterpart at the coordinates:
23:47:10.5 +00:19:11.5 (J2000)(E.S. Rykoff GCN 8084)
Calibrated to near USNO-B1.0 catalog star
with the following results:
time(UT) mid of exp mag. err exposure time
22:39:02 19.6 0.5 80x20 sec
image: http://zeus.asu.cas.cz/~koci/grb080810/GRB080810.jpg
D50 telescope is controled by RTS2 software.
Further analysis is in progress
This message may be cited.
GCN Circular 8093
Subject
GRB 080810: Liverpool Telescope observations
Date
2008-08-11T10:14:52Z (17 years ago)
From
Cristiano Guidorzi at INAF-OAB <cristiano.guidorzi@brera.inaf.it>
C. Guidorzi (INAF-OAB), I. Steele (LJMU), N. Tanvir (U. Leicester)
on behalf of a larger collaboration report:
On 2008 August 11 (03:53:56 UT) we began observing the field of GRB 080810
(Page et al. GCN Circ. 8080) with the Liverpool Telescope using
the r' and i' filters.
The optical afterglow is clearly detected at the position reported
by ROTSE-III (Rykoff GCN Circ. 8084) and the NOT (de Ugarte Postigo
et al. GCN Circ. 8089). We found the following magnitudes:
Telescope Filter T_mid[hr] Exposure[s] Mag
-------------------------------------------------------------
LT i' 14.770 300 19.14 +/- 0.04
LT r' 15.328 300 19.93 +/- 0.04
-------------------------------------------------------------
The calibration was performed using the R2 and I magnitudes
of the following nearby USNOB1 catalogue star: 23:47:06.819,
+00:19:27.15, using R2=15.31, I=14.69.
GCN Circular 8094
Subject
GRB 080810: optical observations
Date
2008-08-11T10:23:24Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
M. Andreev, (Terskol Branch of Institute of Astronomy), Ju. Babina (CrAO),
V. Petkov, A. Kurenya (BNO INR RAS), A. Pozanenko (IKI) on behalf of larger
GRB follow up collaboration report:
We observed the afterglow of GRB080810 (Page et al. GCN 8080) with
Zeiss-600 of Mt.Terskol observatory in R-band on Aug. 11. The afterglow
is detected in a combined image in a position consistent with coordinates
reported by Rykoff (GCN 8084). A photometry of the OT against USNO-B1.0
stars is following:
T0+ Exposure R_mag
(mid)
0.45598 d 8x180 s 19.4 +/- 0.2
GCN Circular 8095
Subject
GRB 080810: Swift/UVOT Refined Analysis
Date
2008-08-11T17:31:57Z (17 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
S. T. Holland (CRESST/USRA/GSFC) & K. L. Page (U Leicester) report on
behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 080810 starting 65 s
after the BAT trigger (Page et al., GCNC. 8080). Settled observations
started at T + 85 s. We detect the optical afterglow (Page et al.,
GCNC 8080) in the v, b, and white filters at the UVOT-enhanced
location of the XRT afterglow (Evans et al., 2008, GCNC 8086). The
refined UVOT source position is
RA (J2000.0) = 23:47:10.48
Dec (J2000.0) = +00:19:11.3
with an estimated uncertainty of +/-0.6 arcsec (radius, 90%
confidence). This is consistent with the positions of the optical
afterglow reported by Rykoff (GCNC 8084) and de Ugarte Postigo (GCNC
8089)
Magnitudes and upper limits are reported below.
Filter T_start (s) T_stop Exposure Mag Err Comment
white 85 185 98 14.63 0.07
v 191 459 264 14.06 0.06
b 4432 4632 197 17.85 0.08
u 4227 68,686 727 >21.4 3-sigma UL
uvw1 4022 68,283 3099 >22.3 3-sigma UL
uvm2 3817 62,540 3229 >22.2 3-sigma UL
uvw2 4843 50,866 1510 >22.0 3-sigma UL
The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.03 mag (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383,627). The
non-detections in the u, uvw1, uvm2, and uvw2 filters are consistent
with a redshift of z = 3.35 (Prochaska, GCNC 8083). The power-law
decay index in the b band between 4532 and 27,387 s is -1.29 +/- 0.22.
[GCN OPS NOTE(10sep08): Per author's request, the RA value
was changed from 23:47:10.26" to "23:47:10.48".]
GCN Circular 8097
Subject
GRB080810: MITSuME optical observation
Date
2008-08-12T09:27:10Z (17 years ago)
From
Michitoshi Yoshida at Okayama Astrophysical Obs <yoshida@oao.nao.ac.jp>
M. Yoshida, K. Yanagisawa, D. Kuroda, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:
We observed the optical afterglow (Ikejiri et al. GCN 8081;
Rykoff GCN 8084) of GRB 080810 (Page et al. GCN 8080) with the
optical three color (g', Rc and Ic) imager attached to the
MITSuME 50cm telescope of Okayama Astrophysical Observatory.
Photometric results are listed below. We used USNO-B1.0 stars
for flux calibration.
Mid-UT exp-T g' Rc Ic
--------------------------------------------------------------
2008-08
10.60244 300 sec 17.16+/-0.06 16.70+/-0.04 15.69+/-0.05
--------------------------------------------------------------
GCN Circular 8098
Subject
GRB 080810: RTT150 optical observations
Date
2008-08-12T14:03:36Z (17 years ago)
From
Irek Khamitov at TUG <irekk@tug.tug.tubitak.gov.tr>
A. Galeev (KSU/AST), I. Khamitov (TUG),
I. Bikmaev, N. Sakhibullin (KSU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
report:
We observed the GRB 080810 afterglow with Russian-Turkish 1.5-m telescope
(RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey).
The serie of 600 sec (Ic), 600 sec (Rc), 900 sec (V) exposures was made
by using TFOSC instrument under moderate seeing, starting at 12 Aug 2008,
01:19 UT, i.e. 36.16 hours after the burst.
The OT is clearly detected on all images. Using USNO-B1.0 stars
we estimate an Rc magnitude of 20.66+/-0.03 (~36.4 hours after the burst).
Using our earlier observations (Burenin et al., GCN8088)
the calculated power law index is -0.91+/-0.09 for decay
from ~8.3 h to ~36.4 h.
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GCN Circular 8099
Subject
GRB 080810: Liverpool and Faulkes North observations
Date
2008-08-12T15:32:08Z (17 years ago)
From
Cristiano Guidorzi at INAF-OAB <cristiano.guidorzi@brera.inaf.it>
C. Guidorzi (INAF-OAB), D. Bersier (LJMU) and N. Tanvir (U. Leicester)
report on behalf of a larger collaboration:
We observed GRB 080810 (Page et al. GCN Circ. 8080) with the 2 m Liverpool
and Faulkes North telescopes starting on August 11 (23:34:09 UT) and
12 (13:14:49 UT), respectively, with r' and i' filters.
We clearly detect the afterglow with the following magnitudes:
Telescope Filter T_mid[hr] Exposure[s] Mag
-------------------------------------------------------------
LT i' 34.657 6x300 20.01 � 0.06
LT r' 39.525 6x300 20.78 � 0.05
FTN i' 48.367 5x300 20.38 � 0.04
-------------------------------------------------------------
The calibration was performed using nearby USNOB1 stars as described
in our previous report (Guidorzi et al. GCN Circ. 8093).
Combining with our previous observation, we derive a power-law index
of 0.94 � 0.05 from 15 to 48 hr post burst, thus confirming the
flattening of the optical decay, in agreement with Galeev et al.
(GCN Circ. 8098).
GCN Circular 8100
Subject
GLAST Burst Monitor detection of GRB 080810
Date
2008-08-12T21:02:21Z (17 years ago)
From
Charles Meegan at NASA/MSFC <charles.a.meegan@nasa.gov>
C.A. Meegan (NASA/MSFC), J. Greiner (MPE), N.P. Bhat (UAH), E. Bissaldi
(MPE), M.S. Briggs (UAH), V. Connaughton (UAH), R. Diehl (MPE), G.J.
Fishman (NASA/MSFC), L. Gibby (NASA/MSFC), A.S. Hoover (LANL), A.J.
van der Horst (NASA/ORAU), A. von Kienlin (MPE), R.M. Kippen (LANL), C.
Kouveliotou (NASA/MSFC), G.G. Lichti (MPE), S. McBreen (MPE), W.S.
Paciesas (UAH), R.D. Preece (UAH), H. Steinle (MPE), M.S. Wallace
(LANL),
and C.A. Wilson-Hodge (NASA/MSFC)report:
"At 13:10:12 UT on 10 August 2008, the GLAST Burst Monitor (GBM)
triggered and located GRB 080810 (GBM 080810.549, trigger 240066613),
which was also detected by Swift (Page et al., GCN 8080).
The on-ground calculated location, using the GBM trigger data, is
RA, Dec 357.18, -4.61 which is equivalent to
RA(J2000) = 23h 49m
Dec(J2000) = -4d 37'
with an uncertainty of 5.0 degrees (radius, 1-sigma containment,
statistical only). The angle from the Large Area Telescope (LAT)
boresight is 61 degrees.
The GBM light curve shows a slow rise starting at T0-20, followed by
a main emission phase comprising 5 pulses, a quiescent period and a
sixth pulse at T0+102 s.
The time-averaged spectrum from T-0.5 to T+53.1 sec is best fit by a
power law function with an exponential high energy cutoff. The cutoff
energy is 313.5 +/-73.6 keV and the power law index is -0.91 +/-0.12,
with a reduced chi-square of 1.1 for 226 degrees of freedom.
The fluence in the 50-300 keV band is (6.9 +/- 0.5) x 10^-6 erg/cm2.
The 1-sec photon flux measured from T+23.5 sec in the 50-300 keV band
is 1.85 +/- 0.16 ph/cm2/sec. All the quoted errors are at the 90%
confidence level."
GCN Circular 8101
Subject
GRB 080810: Konus-Wind and Swift/BAT joint spectral analysis
Date
2008-08-12T21:24:11Z (17 years ago)
From
Takanori Sakamoto at NASA/GSFC <takanori@milkyway.gsfc.nasa.gov>
T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC),
W. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD),
D. Palmer (LANL), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), and T. Ukwatta (GWU)
on behalf of the Swift-BAT team:
V. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team,
Report:
We performed the Konus-Wind and the Swift/BAT joint spectral analysis
of GRB 080810 (Swift/BAT trigger #319584; Page et al., GCN Circ. 8080).
Since the Konus-Wind observed this GRB in the waiting mode, we only
have 3 channel spectral data for the Konus-Wind. However, the
Konus-Wind data covers the energy range from 20 keV to 1 MeV. Therefore,
the joint spectral analysis of the Konus-Wind and the Swift/BAT data
enables to derive the broad-band spectral parameters of this burst.
The time interval of the spectral data for each instrument is chosen from
T0(BAT)-18.6 to T0(BAT)+60.8 sec where T0(BAT) is the trigger time of BAT
at 13:10:12.3 UTC. This time interval includes most of the burst emission,
but not the last pulse around T0(BAT)+~100 sec which is clearly visible in
the BAT data (Sakamoto et al., GCN Circ. 8082). The energy ranges which we
used in the joint spectral analysis are 20-1000 keV and 14-150 keV for
the Konus-Wind and the Swift/BAT respectively. The spectral data of two
instruments are fit with the spectral model multiplied by the constant factor
to take into account the systematic uncertainties in the response matrices
of each instrument.
The spectrum is well fit with a power-law with exponential cutoff model
(dN/dE ~ E^{alpha} * exp(-(2+alpha)*E/Epeak)). The constant factors of each
instrument agree within 20%. No systematic residual from the best fit model
is seen in the spectral data of each instrument. The best fit spectral
parameters are: alpha = -1.2 +- 0.1 and Epeak = 550 (-230/+860) keV
(chi2/dof = 41/58). The best fit spectral parameters for the Band function
fixing beta=-2.5 are: alpha = -1.2 +- 0.1 and Epeak = 580 (-260/+850) keV
(chi2/dof = 41/58). The energy fluence in the 15-1000 keV band calculated
by a power-law with exponential cutoff model for this 79.5 sec interval is 1.7
(-0.2/+0.1) x 10^-5 erg/cm2 (assuming the constant factor of the BAT is fixed to 1).
Assuming z = 3.35 (Prochaska et al., GCN Circ. 8083; Burenin et al.,
GCN Circ. 8088) and a standard cosmology model with H_0 = 71 km/s/Mpc,
Omega_M = 0.27, Omega_Lambda = 0.73, the isotropic energy release is
E_iso ~5 x 10^53 erg in 1 keV to 10 MeV at the GRB rest frame extrapolating
the best fit model spectrum.
All the quoted errors are at the 90% confidence level.
GCN Circular 8102
Subject
GRB 080810: RTT150 optical observations
Date
2008-08-13T13:46:42Z (17 years ago)
From
Irek Khamitov at TUG <irekk@tug.tug.tubitak.gov.tr>
A. Galeev (KSU/AST), I. Khamitov (TUG),
I. Bikmaev, N. Sakhibullin (KSU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
report:
We observed the GRB 080810 afterglow (Page et al. GCN Circ. 8080)
with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK
National Observatory, Turkey).
The series of several exposures in V,Rc,Ic bands were made
by using Andor CCD starting at 13 Aug 2008, 00:24 UT, i.e. ~ 59.23 hours
after the burst.
Using USNO-B1.0 stars we estimate an Rc magnitude of 21.60+/-0.05
(~59.85 hours after the burst).
This measurement deviates from the power law decay with index -0.9
(Galeev et al., GCN8098,Guidorzi et al, GCN8099), that indicates steeper
fading of OT after 48h.
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GCN Circular 8103
Subject
Radio detection of GRB 080810 with the VLA
Date
2008-08-13T17:57:01Z (17 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 field centered at the UVOT position of the Swift burst
GRB 080810 (GCN 8080) using the Very Large Array (VLA) at a frequency
of 8.46 GHz and starting at 2008 Aug 13.36 UT. We detect the radio flux
at the GRB afterglow position with the flux density of 151 � 50 uJy.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
GCN Circular 8105
Subject
GRB080810: optical observations
Date
2008-08-16T02:20:14Z (17 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev, Yu. Efimov (CrAO), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We observed the optical afterglow of GRB080810 (Page et al., GCN 8080)
in R-band on Aug.10 between (UT) 23:17:05 - 23:48:32 with AZT-8 telescope of
CrAO. The afterglow is detect in a separate images in coordinates RA(J2000)
= 23 47 10.4, Dec(J2000) = +00 19 11.0 with uncertainty 0.5". The
coordinates are consistent with reported early (Page et al. GCN 8080,
Rykoff GCN 8084, A. de Ugarte Postigo et al. GCN 8090).
Based on USNO-B1.0 star RA (J2000) = 23 47 11.12, Dec. (J2000) = +00 16
38.30, R=16.30 we estimated brightness of the optical afterglow:
T0+, Exposure, R_mag, err
(mid time)
0.4331 d 15x120 s 19.20 +/- 0.05
GCN Circular 8106
Subject
GRB080810 - optical observations
Date
2008-08-16T21:42:53Z (17 years ago)
From
Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr <cthoene@astro.ku.dk>
Christina C. Thoene (DARK/NBI), Antonio de Ugarte Postigo (ESO) and
Christine Liebig (ARI Heidelberg) report:
We observed the field of GRB 080810 (Page et al. GCN 8080) with the Danish
1.54m telescope on La Silla/Chile on August 15.40 UT and 16.31 UT (4.85
and 5.76 days after the burst onset). We detect the decaying afterglow at
preliminary R-band magnitudes of 22.8+/-0.3 and 23.2+/-0.5.
Using the R band and unfiltered magnitudes published in GCNs (Rykoff et
al. GCN 8084, Burenin et al. GCN 8088, de Ugarte Postigo et al. GCN 8089 &
8090, Okuma et al. GCN 8091, Kocka et al. GCN 8092, Guidorzi et al. GCN
8093 & 8099, Andreev et al. GCN 8094, Yoshida et al. GCN 8097, Galeev et
al. GCN 8098 & 8102, Rumyantsev et al. GCN 8105) together with the data of
our own observations we find that the light curve can be described by a
powerlaw of index alpha = 1.12 +/- 0.02 between 400s and 1 day after the
burst. After 1 day there is a flux excess that can be seen both in the
optical and X-ray light curves (explaining the flattening measured by
Galeev et al., GCN8098 and Guidorzi et al., GCN8099), after which the
light curve begins to decay more steeply with an index in the optical of
alpha = 1.8 +/- 0.3.
Hail, thunderstorm and heavy rain currently prevent further observations
from the DK 1.54m.
C. Thoene and C. Liebig acknowledge the excellent cheese fondue at the
Swiss telescope yesterday evening.
GCN Circular 8722
Subject
GRB 080810: optical observations
Date
2008-12-24T14:21:54Z (16 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (SAI MSU), I. Korobtsev (ISTP), A. Pozanenko (IKI), E. Klunko
(ISTP), N. Bochkarev (SAI MSU), E. Karitskaja (Institute of Astronomy), on
behalf of larger GRB follow up collaboration report:
We observed the afterglow of GRB 080810 (Page et al. GCN 8080) with 1.5 m
telescope of Sayan observatory (Mondy) under good weather conditions.
Series of R and B images were obtained between Aug. 10 (UT)
16:50:03 -18:17:06. While we clearly detect afterglow in single R images,
the afterglow is not detected in a combined image obtained in B. A
photometry of the combined images is based on several SDSS nearby stars:
T0+ Filter Exp. mag. Upper_Limit seeing
mid., days (3 sigma)
0.1599 B 14x60 n/d 19.26 ~2.7"
0.1786 R 30x60 17.98 +/- 0.13 20.85 ~2.2"
0.2026 R 30x60 18.10 +/- 0.17 21.14 ~2.0"
The photometry in R-band is an agreement with power law decay index of
light curve (alpha = 1.12) between 400 s and 1 day after the burst reported
by Thoene et al (GCN 8106).
GCN Circular 8728
Subject
GRB 080810: optical observations
Date
2008-12-25T18:17:47Z (16 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (SAI MSU), R. Karimov (MAO), A. Pozanenko (IKI), M. Ibrahimov
(MAO) on behalf of larger GRB follow up collaboration report:
We observed the afterglow of GRB 080810 (Page et al. GCN 8080) with AZT-22
(1.5 m) telescope of Maidanak observatory (MAO) in R band on Aug. 12 (UT)
(20:18:17 - 21:07:58) and Aug. 14 (20:26:35 - 21:33:00). A photometry of
combined images is based on several SDSS DR6 field stars:
T0+ Filter Exp. mag. UL
mid., days (3 sigma)
2.315 R 2700 21.36 +/-0.09 23.10
4.326 R 3600 n/d 22.30
The photometry in R-band is an agreement with power law decay index (alpha
= 1.8) reported by Thoene et al (GCN 8106) for this phase of the light
curve.