GRB 080916C
GCN Circular 10019
Subject
Radio observation of GRB080916c with ATCA
Date
2009-10-13T09:06:49Z (16 years ago)
From
Aquib Moin at CIRA/ATNF <aquib.moin@postgrad.curtin.edu.au>
Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope
National Facility), Steven Tingay (Curtin Institute of Radio Astronomy),
Chris Phillips (Australia Telescope National Facility), Gregory Taylor
(University of New Mexico), Mark Wieringa (Australia Telescope National
Facility) and Ralph Martin (Perth Observatory) report:
We observed the XRT position of the GRB080916c (GCN 8261) at 5.5 GHz
with the Australia Telescope Compact Array (ATCA) between 14:00:00 UT
and 20:00:00 UT on July 01, 2009.
We did not detect a radio source at the XRT position of the GRB080916c
(GCN 8261). The radio flux density at the afterglow position found out
to be 0.230 +/- 0.180 mJy/beam (1-sigma). The compact array was in its
most compact configuration.
The Australia Telescope Compact Array (/ Parkes telescope / Mopra
telescope / Long Baseline Array) is part of the Australia Telescope
which is funded by the Commonwealth of Australia for operation as a
National Facility managed by CSIRO.
See the 5.5 GHz field image at:
http://cira.ivec.org/dokuwiki/doku.php/grb/grb080916c_field_image
GCN Circular 8278
Subject
GRB 080916C: Fermi GBM Spectral Analysis
Date
2008-09-20T23:41:31Z (17 years ago)
From
Alexander van der Horst at NASA/MSFC <avdhorst@science.uva.nl>
Alexander van der Horst (NASA/ORAU) and Adam Goldstein (UAH) report on
behalf of the Fermi Gamma-ray Burst Monitor Team:
"We have performed spectral analysis of GRB 080916C (GCN 8245, 8246).
The time averaged spectrum, from 8 keV up to 30 MeV, of the main emission
up to 66 seconds after the burst is best fit by a Band function with
Epeak = 424 +/- 24 keV, alpha = -0.91 +/- 0.02, and beta = -2.08 +/- 0.06.
The fluence (8 keV - 30 MeV) is 1.9e-4 erg/cm^2.
These spectral analysis results are preliminary; the final results will
be published in the GBM GRB Catalog."
GCN Circular 8274
Subject
GRB 080916C: IRSF/SIRUS NIR Observation
Date
2008-09-19T14:41:06Z (17 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
T. Nagayama (Kyoto University) reports on behalf of the IRSF/SIRIUS
team:
We have imaged the field of GRB 080916C (van der Horst, GCN 8245)
based on the localization by Fermi/LAT (Tajima et al, GCN 8246) in J, H,
and Ks with the Simultaneous three-color InfraRed Imager for Unbiased
Survey (SIRIUS) on the Nagoya-SAAO 1.4m telescope (IRSF) starting at
2:53 on September 17 UT for 50 min.
The optical afterglow candidate suggested by Clemens et al. (GCN 8257,
GCN 8272) was detected marginally in H and Ks bands.
The preliminary magnitude was Ks= 18.6 +- 0.5.
GCN Circular 8273
Subject
GRB 080916C: GROND Confirmation of the Optical Afterglow
Date
2008-09-19T10:08:07Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
C. Clemens (MPE Garching), A. Rossi (Tautenburg Obs.), J. Greiner, S. McBreen,
T. Kruehler, A. Yoldas (all MPE Garching), A. Kupcu Yoldas (ESO) and G.
Szokoly (Eoetvoes Univ., Budapest) report on behalf of the GROND team:
We observed the field of GRB 080916C for a second time with GROND at 08:04 UT
on September 19th, 2008, 3.3 d after the GBM trigger with 54 min of effective
exposures. Observations were performed at an average seeing of 1.7" and at an
average airmass of 1.7.
We do not detect the afterglow candidate first reported by Clemens et al. (GCN
#8257) with the following 5-sigma upper limits:
z' > 22.7 mag.
These measurements strongly indicate a fading of the source compared to our
first epoch observations. We therefore propose this is to be the afterglow of
GRB 080916C.
GCN Circular 8272
Subject
GRB 080916C: GROND Confirmation of the Optical Afterglow
Date
2008-09-19T10:08:00Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
C. Clemens (MPE Garching), A. Rossi (Tautenburg Obs.), J. Greiner, S. McBreen,
T. Kruehler, A. Yoldas (all MPE Garching), A. Kupcu Yoldas (ESO) and G.
Szokoly (Eoetvoes Univ., Budapest) report on behalf of the GROND team:
We observed the field of GRB 080916C for a second time with GROND at 08:04 UT
on September 19th, 2008, 3.3 d after the GBM trigger with 54 min of effective
exposures. Observations were performed at an average seeing of 1.7" and at an
average airmass of 1.7.
We do not detect the afterglow candidate first reported by Clemens et al. (GCN
#8257) with the following 5-sigma upper limits:
z' > 22.7 mag.
These measurements strongly indicate a fading of the source compared to our
first epoch observations. We therefore propose this is to be the afterglow of
GRB 080916C.
GCN Circular 8262
Subject
GRB 080916C: Swift UVOT Refined Analysis
Date
2008-09-17T17:59:31Z (17 years ago)
From
Erik Hoversten at Swift/Penn State <hoversten@astro.psu.edu>
E. A. Hoversten (PSU), P. Schady (MSSL-UCL), and M. Perri (ASDC)
report on behalf of the Swift UVOT team:
The Swift/UVOT began observations of the field of GRB 080916C 17.0
hours after the Fermi GBM dectection (Goldstein & van der Horst, GCN
8245). No afterglow is detected within the XRT error circle (Evans, et
al., GCN 8255) in any of the observed UVOT filters.
UVOT magnitude 3-sigma upper limits are reported in the following
table:
Filter T_start T_stop Exp(s) Mag (3-sigma upper limit)
-------------------------------------------------------------
v 101253 101857 590 > 19.75
u 96469 97132 645 > 19.99
uvw1 66675 67517 829 > 20.34
uvw1 95562 96462 886 > 20.38
uvm2 61130 66667 1090 > 20.31
uvm2 94655 95555 886 > 20.20
uvw2 100347 101246 886 > 20.43
The quoted upper limits have not been corrected for the large expected
Galactic extinction along the line of sight of E_{B-V} = 0.32 mag
(Schlegel et al., 1998). All photometry is on the UVOT flight system
described in Poole et al. (2008, MNRAS, 383, 627).
GCN Circular 8261
Subject
GRB 080916C: Swift XRT refined analysis
Date
2008-09-17T15:24:55Z (17 years ago)
From
Matteo Perri at ISAC/ASDC <perri@asdc.asi.it>
M. Perri, B. Preger, G. Stratta (ASDC) report on behalf of the
Swift XRT team:
The Swift XRT started observing the field of the FERMI GRB 080916C
(Goldstein et al., GCN Circ. 8245) at 2008-09-16 17:11:28 UT, about
17 hours after the trigger.
We confirm that the X-ray source reported by Kennea (GCN Circ. 8253) is
the afterglow of the GRB.
Using 2614 s of XRT Photon Counting mode data and 2 UVOT images, we find
an astrometrically corrected X-ray position (using the XRT-UVOT
alignment and matching to the USNO-B1 catalogue): RA, Dec = 119.84684,
-56.63801 which is equivalent to:
RA (J2000): 07 59 23.24
Dec (J2000): -56 38 16.8
with an uncertainty of 1.9 arcsec (90% confidence). This position is
consistent with the XRT position reported by Evans et al. (GCN Circ. 8255)
using less data.
The X-ray light curve from T+61 ks to T+102 ks can be fit with a single
power-law model with a decay index of 1.7 (-0.7) (+1.0).
A 7.6 ks exposure X-ray spectrum from T+61 ks to T+102 ks can be well
fit by an absorbed power-law model with a photon index of 2.1 (+0.9 -0.7)
and a column density of 3.7 (+3.3) (-2.1) x 10^21 cm^-2. We note that
the Galactic column density value in the direction of the burst is
1.5 x 10^21 cm^-2.
The observed 0.3-10.0 keV flux is 8.6 x 10-13 erg cm^-2 s^-1 which
corresponds to an unabsorbed flux of 1.5 x 10^-12 erg cm^-2 s^-1.
Providing the source continues to decay at the same rate, we predict an
observed flux of about 3 x 10^-13 erg cm^-2 s^-1 at T+2 days.
This circular is an official product of the Swift-XRT team.
GCN Circular 8258
Subject
Konus-Wind observation of GRB 080916C
Date
2008-09-17T11:30:55Z (17 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:
The long GRB 080916� (Fermi GBM trigger 243216766/080916.009; Goldstein
and van der Horst, GCN 8245; Tajima et al., GCN 8246; Hurley et al., GCN
8251) triggered Konus-Wind at T0=764.632 s UT (00:12:44.632).
The burst light curve shows the main part with a duration of ~70 s
followed by a weak tail seen at least till ~T0+200 s.
As observed by Konus-Wind the burst
had a fluence of (1.24 +/- 0.17)x10^-4 erg/cm2,
and a 256-ms peak flux measured from T0+3.168 s
of (1.19 +/- 0.30)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+71.424 s) is well be fitted (in the 20 keV - 10 MeV
range) by GRBM (Band) model for which:
the low-energy photon index is alpha = -1.040(-0.058, +0.065),
the high energy photon index beta = -2.26(-0.40, +0.21),
the peak energy Ep = 505(-70, +79) keV (chi2 = 75.6/84 dof).
All the quoted errors are at the 90% confidence level.
The Konus-Wind light curve of this GRB is available
at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080916_T00764/
GCN Circular 8257
Subject
GRB 080916C: GROND Detection of the Optical Afterglow Candidate
Date
2008-09-17T10:55:42Z (17 years ago)
From
Christian Clemens at MPE <cclemens@mpe.mpg.de>
C. Clemens (MPE), A. Rossi (Tautenburg Obs.), J. Greiner and S. McBreen (both
MPE) report on behalf of the GROND team:
GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI
telescope at La Silla Observatory (Chile) observed the field of GRB 080916C,
which triggered Fermi GBM (Goldstein et al., GCN #8245) and for which
significant correlated emission was detected by the Fermi LAT (Tajima et al.,
GCN #8246). The field was followed up by Swift XRT (Kennea et al., GCN
#8253).
Observations started at 07:57 UT on September 17th, 2008, 31.7 hr after the
GBM trigger. They were performed at an average seeing of 1.5" and at an
average airmass of 1.7 as well as under bright moon.
We found a faint source at the edge of the astrometrically corrected 2.1''
Swift-XRT error circle reported by Evans et al. (GCN #8255) at
RA (J2000.0) = 07h 59m 23.32s
DEC (J2000.0) = -56d 38' 18.0''
with an uncertainty of 0.5".
Based on the first 50 min of effective exposures, we estimate a preliminary
magnitude of
z' ~ 21.74 mag +/- 0.17.
Given magnitude is calibrated against USNO-B1 field stars.
No statement about variability can be made at this point. Further observations
are planned.
Please note, that no correction for the Galactic foreground reddening of
E(B-V) = 0.32 mag (Schlegel et al., 1998) has been applied.
GCN Circular 8255
Subject
GRB 080916C: Enhanced XRT position
Date
2008-09-17T09:01:33Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans, J.P. Osborne, A.P. Beardmore and M.R. Goad, (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1310 s of XRT Photon Counting mode data and 1 UVOT images, we find an
astrometrically corrected X-ray position (using the XRT-UVOT alignment and
matching to the USNO-B1 catalogue): RA, Dec = 119.84706, -56.63788 which is
equivalent to:
RA (J2000): 07 59 23.29
Dec (J2000): -56 38 16.4
with an uncertainty of 2.1 arcsec (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 is an official product of the Swift-XRT team.
GCN Circular 8253
Subject
GRB 080916C: Swift/XRT detection of possible afterglow
Date
2008-09-17T04:41:53Z (17 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@astro.psu.edu>
Jamie A. Kennea reports on behalf of the Swift Team:
At 17:08 UT, September 16th 2008 Swift began TOO observations of the Fermi
GBM and LAT detected GRB 080916C (GCN 8245,8246). Preliminary analysis of
downlinked data from this observation reveals a single point source
detected in the field of view at RA, Dec = 119.8459, -56.63891 which is
equivalent to:
RA (J2000): 07h 59m 23.0s
Dec (J2000): -56d 38' 20.1"
with an estimated uncertainty of 8 arcsec (radius, 90% confidence). We
note that this point source is uncatalogued and 189 arcseconds from the
center of the Fermi LAT error circle (GCN 8246), within the LAT 90%
confidence error circle. Currently we cannot determine if this source is
fading, and therefore cannot confirm if this source is associated with GRB
080916C. Observations of this source are on-going.
GCN Circular 8251
Subject
IPN Triangulation and Energy Spectrum of GRB080916C
Date
2008-09-16T22:36:31Z (17 years ago)
From
Kevin Hurley at UCBerkeley/SSL <khurley@ssl.berkeley.edu>
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team
E. Bellm, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W.
Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team,
A. von Kienlin, G. Lichti, and A. Rau, on behalf of the
INTEGRAL SPI-ACS GRB team, and
E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci, I. Lapshov,
F. Lazzarotto, L. Pacciani, M. Galli, and M. Marisaldi, on behalf
of the AGILE Team,
report:
GRB080916C (Goldstein and van der Horst, GCN 8245; Tajima et
al., GCN 8246) was also observed by AGILE (MCAL, SuperAGILE, and ACS -
but not localized), RHESSI, INTEGRAL (SPI-ACS), Konus-Wind,
and MESSENGER. A preliminary triangulation gives a long,
narrow error box centered at RA, Dec = 119.830, -56.790 degrees
(0.2 degrees from the center of the LAT error circle), whose
corners are:
RA(2000) DEC(2000)
119.486 -62.130
120.126 -62.702
119.901 -50.632
120.321 -51.274
A figure is posted at ssl.berkeley.edu/ipn3/080916C.
Using the RHESSI data between 100 keV and 17 MeV, the time-integrated
spectrum for the 62-second interval beginning at 00:12:46 UT can be described
by a cutoff power law with alpha ~ -1.2 +/- 0.3, Epeak ~ 1100 +/- 500 keV,
and fluence ~ (9.0 +/- 1.6) x 10^-5 ergs/cm^2 (100 keV - 10 MeV).
Both the triangulation and the energy spectrum can be substantially
improved.
GCN Circular 8246
Subject
GRB 080916C: Fermi LAT observation
Date
2008-09-16T18:25:23Z (17 years ago)
From
Nicola Omodei at INFN(Pisa)/GLAST <nicola.omodei@pi.infn.it>
H. Tajima (SLAC), J. Bregeon (INFN Pisa), J. Chiang (SLAC), G. Thayer (SLAC)
on behalf of the Fermi LAT team:
We report a detection by the Fermi Large Area Telescope (LAT) of
emission from the long GRB 080916C, which was triggered by the Fermi
Gamma-ray Burst Monitor (GBM) at 00:12:45 UT on September 16th 2008 (GCN
8245). The angle of the GBM best position (RA, Dec=121.8,-61.3) with
respect to the LAT boresight was 52 degrees at the time of the trigger,
which is close the edge of our field of view.
The data from the Fermi LAT shows a significant increase in the event
rate within 10 degrees of the GBM location after the GBM trigger that is
spatially and temporally correlated with the GBM emission with high
significance. More than 10 photons are observed above 1 GeV during this
time.
The best LAT on-ground localization is found to be (RA,Dec=119.88,
-56.59) with a 90% containment radius of 0.13 deg (statistical; 68%
containment radius: 0.09 deg, preliminary systematic error is less than
0.1 deg) which is consistent with the GBM localization.
This circular is an official product of the Fermi LAT team.
GCN Circular 8245
Subject
GRB 080916C: Fermi GBM Detection
Date
2008-09-16T18:09:46Z (17 years ago)
From
Alexander van der Horst at NASA/MSFC <avdhorst@science.uva.nl>
Adam Goldstein (UAH) and Alexander van der Horst (NASA/MSFC) report on
behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 00:12:45 UT on 16 September 2008, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located the bright GRB 080916C (trigger 243216766 /
080916.009). The on-ground calculated location, using the GBM trigger data,
is RA = 121.8, Dec = -61.3 (J2000 degrees, equivalent to J2000 8h 07m,
-61d 18'), with a statistical uncertainty of less than 1 degree (radius,
1-sigma
containment) and an additional systematic error which is currently estimated
to be 2 to 3 degrees. The angle from the Fermi Large Area Telescope (LAT)
boresight is 52 degrees.
This GRB has several peaks, with T90 (50-300 keV) = 66 s and
T50 (50-300 keV) = 33 s. This burst is detected up to several MeV;
spectral analysis is ongoing."