GRB 080723B
GCN Circular 8002
Subject
GRB 080723B : a long GRB detected with INTEGRAL
Date
2008-07-23T14:28:26Z (17 years ago)
From
Diego Gotz at CEA <diego.gotz@cea.fr>
D. Gotz (CEA-Saclay), A.Paizis, S.Mereghetti (IASF-Milano),
V.Beckmann, M. Beck, A. Manousakis (ISDC, Versoix), and J. Borkowski
(CAMK, Torun) on behalf of the IBAS Localization Team report:
A bright GRB lasting about 105 s has been detected by IBAS in IBIS/
ISGRI data at 13:22:19 UT on July 23rd 2008. The refined position is
R.A.: 176.8354 deg
Dec.: -60.2452 deg
with an uncertainty of 1.5 arcmin (90% c.l.).
The burst is very bright and has saturated the available telemetry
share. Hence the following preliminary spectral results are to be
considered lower limits. The peak flux over 3 s in the 20-200 keV
energy range is 6 ph/cmsq/s, and the fluence integrated over the
whole burst duration is 1.3e-5 erg/cmsq.
A plot of the light curve will be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
This message can be cited.
GCN Circular 8003
Subject
GRB 080723B: Detection and Localization by SuperAGILE
Date
2008-07-23T14:47:13Z (17 years ago)
From
Marco Feroci at IASF/INAF <feroci@iasf-roma.inaf.it>
E. Del Monte, I. Donnarumma, Y. Evangelista, M. Feroci,
E. Costa, I. Lapshov, F. Lazzarotto, L. Pacciani, M. Rapisarda,
P. Soffitta, (INAF/IASF Rome), A. Giuliani, S. Vercellone, A. Chen,
S. Mereghetti, A. Pellizzoni, F. Perotti, F. Fornari, P.
Caraveo (INAF/IASF Milan), A. Bulgarelli, F. Gianotti,
M. Trifoglio, G. Di Cocco, C. Labanti, F. Fuschino, M. Marisaldi,
M. Galli, (INAF/IASF Bologna), M. Tavani, G. Pucella, F. D'Ammando, V.
Vittorini, A. Argan, A. Trois (INAF/IASF Rome), G. Barbiellini,
F. Longo (INFN Trieste), P. Picozza, A. Morselli (INFN Roma-2),
M. Prest, E. Vallazza (Universita` dell'Insubria), P. Lipari,
D. Zanello (INFN Roma-1), and P. Giommi, C. Pittori, B. Preger,
P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti (ASI),
on behalf of the AGILE Team, report:
"SuperAGILE detected and localized a very bright gamma ray burst
on July 23rd 2008, at 13:22:19 UT. The event was approximately
13 degrees off-axis. The observed duration in the 20-60 keV
energy range is about 110 seconds, with a multi-peaked structure.
The burst position was reconstructed as (RA, Dec) (176.823 deg,
-60.262 deg), which is:
RA(J2000) = 11h 47m 17.42s
Dec(J2000) = -60d 15' 43.7"
with an uncertainty of 3' radius. The given uncertainty accounts
for both the statistical and systematic errors.
The same event was also localized and announced by INTEGRAL/ISGRI
(BACODINE trigger n. 5311, and Gotz et al., GCN 8002).
The SuperAGILE position lies at 1.1 arcmin from the one
reported in the INTEGRAL off-line analysis.
A SuperAGILE light curve of the event will shortly be posted on the AGILE
Science Data Center website: http://agile.asdc.asi.it .
An analysis of the AGILE Gamma Ray Imager (GRID) data is in progress."
This message may be cited.
GCN Circular 8005
Subject
GRB 080723B : Planned XMM-Newton observation
Date
2008-07-23T17:30:53Z (17 years ago)
From
Norbert Schartel at XMM-Newton/ESA <too@xmm.esac.esa.int>
XMM-Newton will observe GRB 080723B at location
(RA=11h 47m 20s, DEC=-60d 14' 41", J2000),
starting at 18:30:00 UT, on July 23, 2008,
for an exposure of 79800 seconds.
XMM-Newton SOC
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GCN Circular 8006
Subject
GRB 080723B: AGILE GRID and MCAL results
Date
2008-07-23T18:38:49Z (17 years ago)
From
Sandro Mereghetti at IASF/CNR <sandro@iasf-milano.inaf.it>
F. Fornari, S. Mereghetti, A. Giuliani, S. Vercellone, A. Chen, A.
Pellizzoni, F. Perotti, P. Caraveo (INAF/IASF Milan), M. Marisaldi, F.
Fuschino, A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco, C.
Labanti, M. Galli (INAF/IASF Bologna), E. Moretti, F. Longo, G.
Barbiellini (INFN Trieste), M. Tavani, G. Pucella, F. D'Ammando, V.
Vittorini, A. Argan, A. Trois (INAF/IASF Rome), E. Del Monte, I.
Donnarumma, Y. Evangelista, M. Feroci, E. Costa, I. Lapshov, F.
Lazzarotto, L. Pacciani, M. Rapisarda, P. Soffitta (INAF/IASF Rome), P.
Picozza, A. Morselli (INFN Roma-2), M. Prest, E. Vallazza (Universita`
dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), P. Giommi, C.
Pittori, B. Preger, P. Santolamazza, F. Verrecchia (ASDC) and L. Salotti
(ASI), on behalf of the AGILE Team, report:
Analysis of the AGILE Gamma Ray Imager Detector (GRID) data of the
INTEGRAL GRB 080723B (Gotz et al. GCN 8002, Del Monte et al. GCN 8003)
does not reveal significant high-energy emission during the time interval
of the prompt emission.
A preliminary estimate of the fluence, integrated over 100 s, gives a 99%
c.l. upper limit of 0.03 photons/cm^2 for energy greater than 50 MeV.
GRB 080723B has also triggered on-board the AGILE Mini-Calorimeter (MCAL)
at 13:22:33 UT (=T0). Using the preliminary in-flight calibration and
assuming a Crab-like spectrum we can estimate a fluence of (8 +/- 2)x10^-6
erg/cm^2 in the 350-700 keV energy range in the time interval between T0
and T0+48 s.
This message may be cited.
GCN Circular 8008
Subject
GRB 080723B - Swift-XRT position
Date
2008-07-23T20:58:43Z (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:
Swift started observing the INTEGRAL- and Super-AGILE-detected GRB 080723B
~13.4 ks after the trigger (Gotz et al., GCN Circ. 8002; Del Monte et al.,
GCN Circ. 8003). In ~560 s of data, the XRT clearly detects a source
within the error circles, at a position of RA, Dec = 176.83393,
-60.2414, which is equivalent to
RA(J2000) = 11 47 20.14
Dec(J2000) = -60 14 29.1
with an uncertainty of 3.9 arcsec (radius, 90% containment).
Currently there are insufficient data to say whether the source is fading.
An updated circular will be written when further data have been obtained.
This is an official product of the Swift-XRT team.
GCN Circular 8009
Subject
GRB 080723B - Swift-XRT refined analysis
Date
2008-07-24T07:01:14Z (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:
The INTEGRAL/Super-AGILE-detected GRB 080723B has now been observed by the
Swift-XRT for three orbits (a total of ~2.3 ks of Photon Counting mode
data). The source reported in GCN Circ. 8008 can now be seen to be fading
(alpha = 1.27 +/- 0.23), so is confirmed as the X-ray afterglow.
A spectrum formed from the combined data (~1.3 - 30 ks after the triggers)
can be fitted by a power-law of Gamma = 1.87 +/- 0.14, absorbed by the
Galactic column in this direction, of 7.42x10^21 cm^-2. The average
observed (unabsorbed) flux over this time is 1.49 (2.57) x 10^-9 erg cm^-2
s^-1, which provides an observed counts to flux conversion of 5.9x10^-9
erg cm^-2 count^-1.
If the decay were to continue with alpha ~1.27, the count rate 24 hours
after the trigger woule be 0.04 count s^-1 (corresponding to an observed
flux of 2.4x10^-10 erg cm^-2 s^-1).
The circular is an official product of the Swift-XRT team.
GCN Circular 8010
Subject
GRB 080723B - correction to flux conversion factor
Date
2008-07-24T08:15:47Z (17 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
K.L. Page and J.P. Osborne (U. Leicester) report on behalf of the
Swift-XRT team:
The counts to flux conversion factor in GCN Circ. 8009 was inadvertantly
mistyped. The actual conversion is 5.9x10^-11 erg cm^-2 count^-1 (a factor
of 100 lower than that previously given). This implies that the predicted
flux at 24 hours is 2.4x10^-12 erg cm^-2 s^-1.
We apologise for the mistake and any inconvenience it may have caused.
GCN Circular 8013
Subject
ATCA radio upper limit on GRB 080723B
Date
2008-07-25T02:06:42Z (17 years ago)
From
Poonam Chandra at U Virginia/NRAO <pc8s@virginia.edu>
Mark H. Wieringa (CSIRO), Poonam Chandra (NRAO/UVA) and Dale A. Frail
(NRAO) report on behalf of a larger collaboration:
"We observed a region centered on the bright INTEGRAL- and
Super-AGILE-detected GRB 080723B (GCN 8002 and 8003) using the Australia
Telescope Compact Array starting at July 23.97 UT and ending at
July 24.13 UT. No radio emission was seen at 8 GHz frequency band
within the XRT error circle (GCN 8008). The flux upper limit at XRT
position is 170 uJy (rms 67 uJy).
The Australia Telescope Compact Array is part of the Australia
Telescope which is funded by the Commonwealth of Australia for
operation as a National Facility managed by CSIRO.
GCN Circular 8015
Subject
Konus-Wind observation of GRB 080723B
Date
2008-07-25T11:33:12Z (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 bright GRB 080723B localized by IBIS/ISGRI (Gotz et al., GCN 8002)
and SuperAGILE (Del Monte et al., GCN 8003) triggered Konus-Wind at
T0=48143.773 s UT (13:22:23.773).
The burst light curve shows multipeaked structure with a duration of ~100 s.
As observed by Konus-Wind the burst
had a fluence of 8.40(-0.56, +0.47)x10^-5 erg/cm2,
and a 64-ms peak flux measured from T0+54.784 s
of (1.11 +/- 0.15)x10^-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+87.808 s) is well fitted (in the 20 keV - 2 MeV range)
by GRBM (Band) model for which:
the low-energy photon index is alpha = -0.755 (-0.102, +0.103),
the high energy photon index beta = -2.42(-0.40, +0.18),
the peak energy Ep = 225(-21, +27) keV (chi2 = 64.2/58 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/GRB080723_T48143/
GCN Circular 8017
Subject
GRB080723B: Swift/UVOT Upper Limits
Date
2008-07-25T13:03:18Z (17 years ago)
From
Peter Brown at PSU <pbrown@astro.psu.edu>
P. J. Brown (Penn State) reports on behalf of the Swift UVOT team:
The Swift/UVOT observed the field of GRB 080723B (Gotz et al.,
GCN Circ. 8002) starting at 2008-07-23 17:05:44, 13.4 ks after
the Integral detection. We do not find any source in the UVOT
observations at the XRT position of the afterglow (Page, GCN Circ. 8008).
The 3-sigma upper limits for detecting a source at this location in the
co-added images are:
Filter T_start(s) T_stop(s) Exp(s) Mag(3-sigma upper limit)
v 13790 13836 45 >18.1
b 13551 35434 473 >20.3
u 13500 35220 661 >20.1
uvw1 13405 40586 1538 >20.4
uvm2 13841 13966 124 >18.8
uvw2 13603 35801 735 >20.1
The values quoted above are in the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627). They have not been corrected
for the expected high but uncertain Galactic extinction along the
line of sight (Galactic latitude < 5 degrees).
GCN Circular 8078
Subject
GRB 080723B: XMM-Newton observation
Date
2008-08-08T20:16:55Z (17 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
G. Sala, J. Greiner, S. McBreen, T. Kruehler, P.M. Esquej (all MPE Garching,
Germany) report:
XMM-Newton observed GRB 080723B detected by INTEGRAL (Gotz et al. 2008,
#GCN 8002) and AGILE (Del Monte et al. 2008, GCN #8003), starting at
18:47:41 UT, on July 23, 2008, for an exposure of 62.5 ks (Schartel 2008,
GCN 8005). The observation was affected by background radiation flaring,
reducing the good exposure time to 54 ks.
GRB 080723B is detected with an average count rate of 0.9, 0.3 and 0.01 cts/s
in the EPIC-pn, MOS1/2 and RGS instruments, respectively. Here we report
on a refined position and the X-ray spectrum of the afterglow of GRB 080723B.
By identifying four X-ray sources in the FOV of the EPIC camera with
counterparts from the 2MASS catalogue, we are able to register the X-ray
coordinate system, and obtain a best-fit X-ray position of the afterglow
of GRB 080723B of RA = 176.83317, Decl. = -60.24096, equivalent to
RA (2000.0) = 11 47 20.09
Dec (2000.0) = -60 14 28.6
with an uncertainty of 2.0 arcsec. This coincides perfectly with the X-ray
position reported by Swift/XRT (Page 2008, GCN #8008), but reduces the
error circle by nearly a factor of two.
The X-ray flux during the XMM-Newton observation decays gradually, with no
noticable deviations from a power law of slope 1.50 +/-0.05, compatible
within the error with the flatter Swift/XRT decay (Page 2008, GCN #8009).
The spectrum averaged over the full observation (25.7 - 65.7 ks after the
GRB trigger) can be fitted by an absorbed power-law with photon index
Gamma = 1.79 +/-0.02, and an equivalent hydrogen column of
1.22(+/-0.02)*10^22 cm^-2, in excess of the catalogued Galactic column
in this direction, 7.4*10^21 cm^-2 (Kalberla et al. 2005, AA 440, 775;
Dickey & Lockman 1990, ARAA 28, 215). Being at a Galactic latitude of
1.6 deg, this difference may be due to clumpiness of foreground material
relative to the spacing of the above HI surveys, rather than necessarily
due to intrinsic extinction in the GRB host galaxy. The observed 0.3-10 keV
flux during the XMM-Newton observation decreases from about
1*10^-11 erg/cm^2/s (26 ks after burst trigger) to
2.5*10^-12 erg/cm^2/s (65 ks post-burst).
We thank Ignacio de la Calle, Nora Loiseau and Norbert Schartel from the
XMM-Newton SOC (Villafranca, Spain) for scheduling and executing this
observation.
GCN Circular 8079
Subject
GRB 080723B: GROND upper limits
Date
2008-08-08T20:19:08Z (17 years ago)
From
Jochen Greiner at MPI <jcg@mpe.mpg.de>
T. Kruehler, J. Greiner, F. Schrey, G. Sala, C. Clemens (all MPE Garching)
report on behalf of the GROND team:
We observed the field of the INTEGRAL GRB 080723B (Gotz et al. 2008,
GCN #8002) on two epochs, simultaneously in g'r'i'z'JHK with GROND
(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope
at La Silla Observatory (Chile). First observations started at
2008-07-24 23:46 UT, 36.4 h after the burst, with total exposures of
50 min in g'r'i'z' and 40 min in JHK. A second set of images was obtained
starting at 2008-07-31 23:39 UT with effective exposures of 100 min
(g'r'i'z') and 80 min (JHK).
We do not detect a fading source in neither the XRT (Page 2008, GCN #8008)
nor XMM (Sala et al. 2008, GCN #8078) error circle down to limiting
magnitudes of:
g' > 23.4
r' > 23.6
i' > 22.7
z' > 22.7
J > 20.6
H > 19.5
K > 18.5
calibrated against USNO-B1 and 2MASS field stars. At longer wavelength,
these limits are compromised by the high density of foreground stars.
The reported upper limits are not corrected for the expected Galactic
foreground extinction corresponding to a reddening of E_(B-V) = 1.3
(Schlegel et al. 1998).