GRB 040924
GCN Circular 2833
Subject
GRB 040924: Afterglow Color
Date
2004-11-08T17:34:49Z (21 years ago)
From
Matt Bayliss at UNC,Chapel Hill <mbayliss@physics.unc.edu>
J. Silvey, D. Allen, M. Bayliss, M. Nysewander, T. Tilleman, A. Henden, M.
Leake, A. Homewood, R. Canterna, D. Reichart, D. H. Hartmann, and M.
Schwartz report on behalf of the U. Wyoming, U. North Carolina, USNO, and
SARA GRB teams of the FUN GRB collaboration:
We observed the afterglow location (Fox & Moon, GCN 2734) of the short/soft
GRB 040924 (Fenimore et al., GCN 2735) in VRcIcH beginning 16.2 hours after
the burst. Using the field calibrations of Henden (GCN 2811) and 2MASS, we
report the following magnitudes:
Start Mean Time Filter Exposure Magnitude Telescope
Date Since GRB Time (sec) (1)
(hours) x Exposures
Sep 25.171 16.44 Rc 300 x 4 >18.9 0.9m SARA
Sep 25.191 16.89 Ic 300 x 4 >20.6 0.9m SARA
Sep 25.209 17.31 V 300 x 4 >19.6 0.9m SARA
Sep 25.228 18.32 H 800 x 4 >19.5 1.55m NOFS
Sep 25.328 21.18 Ic 300 x 24 >21.7 0.8m TII(2)
Sep 25.391 21.86 Rc 300 x 3 22.68+/-0.07 2.3m WIRO
Sep 25.395 21.96 V 300 x 3 23.06+/-0.07 2.3m WIRO
(1) Limiting magnitudes are 2 sigma.
(2) Tenagra II
Compared to the R observations of Fox (GCN 2741) and Pavlenko et al. (GCN
2753), our Rc observation is generally consistent with a temporal index of
approx. -1.
Assuming a temporal index of -1.16 (Khamitov et al., GCN 2749) and using
this index to scale our observations and the K' observation of Terada et
al. (GCN 2750) to 21.9 hours after the burst, and correcting for Galactic
extinction along the line of sight assuming that R_V = 3.1, yields a
spectral index of -0.61 +/- 0.08:
www.physics.unc.edu/~mbayliss/grbdata/grb040924spec.eps
If source-frame extinction is negligible, this is consistent with either a
constant-density or wind-swept medium with the cooling break blueward of
the observed bands. It is inconsistent with either a constant-density or
wind-swept medium with the cooling break redward of the observed bands
(e.g., Sari, Piran & Narayan 1998, ApJ, 497, L17; Chevalier & Li 2000; ApJ,
536, 195).
However, if source-frame extinction is non-negligible this is only
consistent with a wind-swept medium with the cooling break blueward of the
observed bands.
GCN Circular 2811
Subject
GRB040924, BVRcIc field calibration
Date
2004-10-16T02:36:15Z (21 years ago)
From
Arne A. Henden at USNO/USRA <aah@nofs.navy.mil>
A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:
We have acquired BVRcIc all-sky photometry for
a 11x11 arcmin field centered on the afterglow coordinates
(Fox and Moon, GCN 2734) for the HETE burst GRB040924
(trigger 3564; Fenimore et al., GCN 2735)
with the USNOFS 1.0-m telescope on one photometric
night. Stars brighter than V=14 are saturated and
should be used with care. We have placed the photometric data
on our anonymous ftp site:
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb040924.dat
The astrometry in this file is based on linear plate solutions
with respect to UCAC2. The external errors are less than 100mas.
The estimated external photometric error is about 0.03mag
and will be improved with additional calibration nights
later this week, weather permitting.
As always, you should check the dates on the .dat file prior to
final publication to get the latest photometry. There is
a README file on the ftp directory to give you information
about the procedures used to calibrate these fields.
GCN Circular 2800
Subject
GRB 040924: VLT spectroscopy
Date
2004-10-13T14:54:11Z (21 years ago)
From
Rhaana Starling at GRACE/U of Amsterdam <starling@science.uva.nl>
Klaas Wiersema (University of Amsterdam), Rhaana L.C. Starling
(University of Amsterdam), Evert Rol (University of Leicester),
Paul Vreeswijk (ESO), Ralph A.M.J. Wijers (University of Amsterdam)
report on behalf of the GRACE collaboration:
"We have obtained two spectra of the host galaxy of GRB 040924
(GCN #2735, 2734) with the FORS2 long slit spectrograph on the
ESO VLT (Antu) on 10 October 2004, approx. 15.75 days after burst.
The first spectrum was taken at 05:10 UT using the 300V grism, with
an exposure time of 1800 s; the second spectrum was taken at 05:48 UT
using the 300I grism, again with an exposure time of 1800 s. We used
a 1 arcsec slit. The total wavelength range is approx. 400 - 950 nm.
We find weak emission lines in the spectra, which we identify with
[OII] 3727, [NeIII] 3968.9, H gamma, H beta and [OIII] 4959,5007.
All of these lines are consistent with a redshift z = 0.859.
The presence of [NeIII] implies a galaxy with a significant
population of massive stars. The isotropic energy of the burst is
E_iso=1.48x10^52 erg, using the 25-100 keV fluence value from HETE
and a cosmology with H_0=70 km/s/Mpc, Omega_matter=0.3 and
Omega_lambda=0.7. As the lightcurve breaks fairly early on, the true
energy is likely to be much lower.
The presence of continuum features relating to a supernova
can only be determined after further analysis: a SN1998bw-like bump
would be expected to peak at approximately t_V~23.5 days, t_R~25 days and
t_I~26 days with magnitudes V~25.4, R~24.6 and I~23.8.
We acknowledge excellent support from the staff of Paranal Observatory
and ESO's PSO and USG."
GCN Circular 2759
Subject
GRB 040924: Second Epoch WSRT Radio Observations
Date
2004-10-01T12:49:59Z (21 years ago)
From
Alexander van der Horst at U of Amsterdam <avdhorst@science.uva.nl>
A.J. van der Horst (University of Amsterdam), E. Rol (University of
Leicester) and R.A.M.J. Wijers (University of Amsterdam) report on behalf
of a larger collaboration:
"We reobserved the position of the GRB 040924 afterglow at 4.9 GHz with
the Westerbork Synthesis Radio Telescope from September 29 19.06 UT to
September 30 6.81 UT, i.e. 5.30 - 5.79 days after the burst (GCN 2735).
The rms noise in het map around that position is 30 microJy per beam. The
formal flux measurement for a point source at the location of the optical
afterglow (GCN 2734) is 11 +/- 30 microJy.
In conclusion, we do not detect a source at the optical position, in
agreement with our previous WSRT measurements (GCN 2746) and the VLA
measurements (GCN 2758).
No further observations are planned."
This message may be cited.
GCN Circular 2758
Subject
radio observations, GRB 040924
Date
2004-09-30T21:16:19Z (21 years ago)
From
Dale A. Frail at NRAO <dfrail@nrao.edu>
D. A. Frail (NRAO) and A. M. Soderberg (Caltech) report on behalf of a
larger collaboration:
"On 2004 Sept. 30.28 UT we used the VLA to observe a field centered on
the candidate optical afterglow (GCN 2734) of GRB040924 (GCN 2735).
There are no radio sources at 8.46 GHz in the vicinity down to
a 3-sigma limit of 147 microJy.
Further observations are planned."
GCN Circular 2754
Subject
Konus-Wind and Helicon-Coronas-F observations of GRB040924
Date
2004-09-28T13:47:10Z (21 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks
on behalf of Konus-Wind and Helicon/Coronas-F teams,
T. Cline on behalf of the Konus-Wind team, report:
A soft short GRB040924 (=H3564, GCN 2735) was detected by Konus-Wind
at 11.52.15.280 UT and Helicon-Coronas-F at 11:52:12.691 UT.
It had a duration of approximately 1.5s in the 20-300 keV band.
As observed by Konus-Wind it had
a 20-500 keV fluence of (2.73 +/- 0.12)E-6 erg/cm2,
a 20-500 keV peak flux (3.33 +/- 0.35)E-6 erg/cm2 s over 0.064 s,
and Epeak of the time-integrated spectrum of 67 +/- 6 keV.
We have triangulated it to an annulus:
RA(2000) = 339.625 deg,
Decl(2000) = -5.584 deg,
Radius = 56.049 +/- 1.038 degrees (3 sigma).
This annulus encompasses the HETE WXM error circle reported in GCN 2735.
The center of the annulus passes 0.29 deg (0.84 sigma) from the center
of HETE error circle and 0.25 deg (0.7 sigma) from the position of
the OT given by Fox and Moon (GCN 2734).
GCN Circular 2753
Subject
GRB040924,optical observation
Date
2004-09-27T14:30:35Z (21 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Pavlenko, S. Sergeev, V.Rumyantsev (CrAO), A.Pozanenko (IKI) report:
We observed the field of the optical afterglow candidate (Fox and Moon, GCN
2734) of GRB 040924 (=H3564, Fenimore et al., GCN 2735) in the R (Johnson)
band with APOGEE 47 on the 38-cm Cassegrain telescope of the Crimean
Astrophysical Observatory.
The observations were started at Sep. 24, 20:21 UT (i.e. 8.48 hours after
the burst) and continued up to Sep.24, 23.13 UT. The sum of the first 3
images
(3x190-s) yield the limiting magnitude 19.7 +- 0.2. No optical counterpart
at the position proposed by Fox and Moon was found. For the sum of last
7x240 images taken between Sep. 24 23:08 - 23:46 UT no counterpart fainter
than 21.0 +- 0.2 was detected. The limiting magnitudes were estimated in
comparison of the USNO-B1.0 stars as photometric sequences. The limits are
in agreement with OT magnitude estimation in simultaneous observation of
I.Khamitov et al. (GCN 2749).
This message may be cited.
GCN Circular 2752
Subject
GRB040924, RTT150 optical observation
Date
2004-09-26T21:01:40Z (21 years ago)
From
Irek Khamitov at TUG <irekk@tug.tug.tubitak.gov.tr>
I. Khamitov, Z. Aslan (TUG), C. Yesilyaprak (Akdeniz Univ.),
U. Kiziloglu (METU), E.Gogus, A. Alpar (Sabanci Univ.),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Bikmaev, N. Sakhibullin (KSU)
report:
We observed the afterglow of GRB 040924 (Fenimore et al. GCN 2735, Fox
and Moon, GCN 2734) with Russian-Turkish 1.5-m telescope (Bakyrlytepe,
TUBITAK National Observatory, Turkey). We made 33x300s images in R between
Sep. 25, 23:45 UT, and Sep. 26, 2:45 UT. The observations were hampered by
the bright-moon and bad seeing (1.7 arcsec). The object was clearly
detected near the limit of the combined image. We estimate its magnitude
to be m_R=23.7+/-0.2.
This magnitude is consistent with power law decay with index -1.16,
obtained in our previous observations (GCN 2749). The KAIT earlier
measurements (GCN 2748) seem to be consistent with this power law as well.
Therefore, to the first approximation, the whole light curve of the GRB
040924 afterglow can be described as a single power law with index -1.16.
The combined light curve can be found at:
http://hea.iki.rssi.ru/~rodion/040924/lc_all.jpg
or
http://www.tug.tubitak.gov.tr/~irekk/grb/grb040924/lc_all.jpeg
The finding charts:
http://hea.iki.rssi.ru/~rodion/040924/fcharts.html
or
http://www.tug.tubitak.gov.tr/~irekk/grb/grb040924/fcharts.html
This message may be cited.
GCN Circular 2751
Subject
GRB040924,optical observation
Date
2004-09-26T16:49:37Z (21 years ago)
From
Eri Sonoda at U of Miyazaki/Japan <sonoda@astro.miyazaki-u.ac.jp>
E.Sonoda,S.Maeno,Y.Matsuo,M.Yamauchi
(University of Miyazaki)
"We have observed the field covering the error box of
GRB040924 (HETE trigger 3564; trigger time 11:52:11 UT)
with unfiltered CCD camera on the 30-cm telescope at
University of Miyazaki.The observation was started
15:53:50 UT on Sep.24.
Observed field of view is 43 arcmin centerd on
R.A.= 02h 06m 56.75s , Dec.= +16d 07m 27.5s,and include
the position given by D.B.Fox and D.-S.Moon (GCN 2734).
After co-adding a set of 3 images of 30 sec exposures,
we have compared with the USNO A2.0 catalog. Preliminary
analysis shows there is no new sorce brighter than 16.6 mag."
GCN Circular 2750
Subject
GRB 040924: detection of possible host galaxy by Subaru
Date
2004-09-26T03:45:04Z (21 years ago)
From
Nobuyuki Kawai at Tokyo Tech <nkawai@hp.phys.titech.ac.jp>
H. Terada, M. Akiyama (Subaru Telescope, NAOJ) and N. Kawai (Tokyo
Tech) report:
"We have made the second epoch observation of the afterglow candidate
(GCN 2734) of GRB 040924 (=H3564, GCN 2735) in the K'-band with IRCS
on the 8.2m Subaru Telescope at 15:07-15:41 UT on September 25 (27.5
hours after the burst) for an integration time of 1200 seconds with an
average seeing of 0.52 arcsec.
At the position of the afterglow, we detected an extended source with
magnitude K'=20.4 +/- 0.2. It is probably the afterglow of GRB 040924
with a significant contribution from its host galaxy. Comparison with
the earlier flux (K'=17.5 at t=2.4 hr, Terada and Akiyama, GCN 2742)
imply that the NIR afterglow decay index was steeper than -1.
The image is available at
http://www.hp.phys.titech.ac.jp/nkawai/grb/040924/."
GCN Circular 2749
Subject
GRB040924, RTT150 optical observation
Date
2004-09-25T18:40:55Z (21 years ago)
From
Irek Khamitov at TUG <irekk@tug.tug.tubitak.gov.tr>
I. Khamitov, Z. Aslan (TUG), C. Yesilyaprak (Akdeniz Univ.), U. Kiziloglu (METU),
E. Gogus, A. Alpar (Sabanci Univ.), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Bikmaev, N. Sakhibullin (KSU)
report:
We observed the error box of GRB 040924 (Fenimore et al., GCN 2735) with
Russian-Turkish 1.5-m telescope (Bakyrlytepe, TUBITAK National Observatory,
Turkey). During continuous observations of the afterdlow candidate from
Sep. 24, 20:50UT to Sep. 25, 02:40UT (8.96--14.94 hours after the burst)
weobtained 64x300s images in R. The observations were made under moderate
atmospheric conditions.
We found that the afterglow candidate (Fox and Moon, GCN 2734) faided by
approximately 0.6 mag, from m_R=22.1 to 22.7, during our observations,
which corresponds to power law decay with index -1.16.
The absolute calibration was done according our mean photometric
solutions. For comparison one can use star at 02:06:23.3 +16:07:13 wich
has m_R=19.8 according to our solutions. Brighter magnitide, reported by
Fynbo et al. (GCN 2747) most likely is due to the difference in absolute
calibration.
Our light curve can be found at:
http://hea.iki.rssi.ru/~rodion/040924/lc_0924.jpg
This message may be cited
GCN Circular 2748
Subject
GRB040924: KAIT observations
Date
2004-09-25T18:08:29Z (21 years ago)
From
Weidong Li at UC Berkeley KAIT/LOSS <weidong@astron.berkeley.edu>
W. Li, A. V. Filippenko, R. Chornock, and S. Jha (University of
California, Berkeley) report:
"The Katzman Automatic Imaging Telescope (KAIT; see Li et al. 2003,
PASP, 115, 844) at Lick Observatory robotically observed GRB 040924
(HETE Trigger #3564). Three batches of observations (a total of 34
images) were taken during the first 100 minutes after the burst. Our
first exposure began at 11:52:55 UT, only 44 seconds after burst.
Unfortunately, owing to the relatively small field of view of KAIT
(6.7' x 6.7'), the OT reported by Fox and Moon (GCN 2734) was slightly
outside our field of view in this image and in most of the subsequent
images. The OT was detected only in two sets of images taken during
our 2 x 2 mosaic procedure. From a 120 s unfiltered exposure that
started at 12:18:21 UT, we measured a magnitude of 18.3 (USNO-A2.0
red mag calibrations) for the OT. The object declined to mag 19.2
in a 120 s image that started at 12:55:21 UT. Referenced to the
time of the burst, this corresponds to a decay with power-law index
alpha approximately equal to -1.0.
We also obtained six 300 s KAIT unfiltered images (with the mean
epoch at 8:50 UT) of GRB 040924 on Sep 25 UT. We did not detect
the OT in the combined image, which has a 3-sigma limit of about
mag 22.5."
GCN Circular 2747
Subject
GRB040924: Afterglow magnitude at t=17.5hr
Date
2004-09-25T14:10:40Z (21 years ago)
From
Johan U. Fynbo at U.Copenhagen <jfynbo@astro.ku.dk>
J. P. U. Fynbo (U. Copenhagen), A. Hornstrup (DSRI), J. Hjorth (U.
Copenhagen), B. L. Jensen (U. Copenhagen), Michael I. Andersen (AIP)
report on behalf or a larger collaboration:
"We have observed the afterglow of GRB 040924 (Fenimore et al. GCN
#2735; Fox et al. GCN #2734, GCN #2741) with the 2.56-m Nordic Optical
Telescope on La Palma. By stacking 9 300sec exposures in the R-band with
a mean epoch of Sep 25 5.25 UT we detect a source at the position of the
candidate afterglow reported by Fox et al. Assuming a magnitude of
R=19.1 for the nearby star U1050_00580520 we estimate that the afterglow
flux is around R=22.1 17.5 hours after the burst. This implies the the
lightcurve has become steeper than the slope of -0.7 during the first
hour reported by Fox et al. (GCN #2741)."
[GCN OPS NOTE: This circular was delayed 1.6 hr due to a change in the submiter's
email domain.]
GCN Circular 2746
Subject
GRB 040924: WSRT Radio Observations
Date
2004-09-25T14:06:38Z (21 years ago)
From
Alexander van der Horst at U of Amsterdam <avdhorst@science.uva.nl>
A.J. van der Horst (University of Amsterdam), E. Rol (University of
Leicester) and R.A.M.J. Wijers (University of Amsterdam) report on behalf
of a larger collaboration:
"We observed the position of the GRB 040924 afterglow at 4.9 GHz with the
Westerbork Synthesis Radio Telescope at September 25, 0.41 - 7.36 UT, i.e.
12.54 - 19.49 hours after the burst (GCN 2735). We do not detect a radio
source at the position of the optical afterglow (GCN 2734