GRB 070707
GCN Circular 6605
Subject
GRB 070707: A long GRB detected by INTEGRAL
Date
2007-07-07T22:21:44Z (18 years ago)
From
Volker Beckmann at ISDC <Volker.Beckmann@obs.unige.ch>
V. Beckmann, C. Ricci, M. Beck (ISDC, Versoix), S. Mereghetti, A.
Paizis (IASF-Milano), D. Gotz (CEA-Saclay), and J. Borkowski (CAMK,
Torun) on behalf of the IBAS Localization Team report:
A GRB lasting about 100 s has been detected by IBAS in IBIS/ISGRI data
on July 7 at 16:08:21 UT.
The coordinates (J2000) are:
RA: 267.67 [degrees]
DEC: -68.95 [degrees]
with an uncertainty of 4 arcmin. The light curve is a single,
FRED-like peak. This message can be cited.
GCN Circular 6606
Subject
GRB 070707: A long GRB detected by INTEGRAL
Date
2007-07-07T23:05:21Z (18 years ago)
From
Volker Beckmann at ISDC <Volker.Beckmann@obs.unige.ch>
V. Beckmann, C. Ricci, M. Beck (ISDC, Versoix), S. Mereghetti, A.
Paizis (IASF-Milano), D. Gotz (CEA-Saclay), and J. Borkowski (CAMK,
Torun) on behalf of the IBAS Localization Team report:
A GRB lasting about 100 s has been detected by IBAS in IBIS/ISGRI data
on July 7 at 16:08:21 UT.
The coordinates (J2000) are:
RA: 267.67 [degrees]
DEC: -68.95 [degrees]
with an uncertainty of 4 arcmin. The light curve is a single,
FRED-like peak. This message can be cited.
GCN Circular 6607
Subject
INTEGRAL GRB 070707 is a short hard burst
Date
2007-07-07T23:37:18Z (18 years ago)
From
Diego Gotz at IASF-CNR <dgotz@cea.fr>
D. Gotz (CEA Saclay), V. Beckmann (ISDC, Versoix), S. Mereghetti, and
A. Paizis (IASF, Milano) on behalf of the IBAS localization Team report:
A refined analysis of GRB 070707 shows that it is composed by a single
spike lasting about 1.1 s, and its spectrum can be well fit with a power
law of slope 1.4, indicating a rather hard spectrum.
Its refined position is
R.A. (J2000): 267.7506 [degrees]
DEC. (J2000): -68.9144 [degrees]
with an uncertainty of 2.1 arcmin (90% c.l.)
This messages can be cited.
GCN Circular 6608
Subject
INTEGRAL GRB 070707 is a short hard burst
Date
2007-07-08T00:24:38Z (18 years ago)
From
Diego Gotz at IASF-CNR <dgotz@cea.fr>
D. Gotz (CEA Saclay), V. Beckmann (ISDC, Versoix), S. Mereghetti, and
A. Paizis (IASF, Milano) on behalf of the IBAS localization Team report:
A refined analysis of GRB 070707 shows that it is composed by a single
spike lasting about 1.1 s, and its spectrum can be well fit with a power
law of slope 1.4, indicating a rather hard spectrum.
Its refined position is
R.A. (J2000): 267.7506 [degrees]
DEC. (J2000): -68.9144 [degrees]
with an uncertainty of 2.1 arcmin (90% c.l.)
This messages can be cited.
GCN Circular 6609
Subject
GRB 070707: VLT observations
Date
2007-07-08T11:34:53Z (18 years ago)
From
Silvia Piranomonte at OAR <piranomonte@mporzio.astro.it>
P. D'Avanzo (INAF-OABr), S. Piranomonte, L. Stella (INAF-OAR) and G.
Chincarini ((INAF-OABr) report on behalf of the MISTICI collaboration:
We observed the field of the short GRB 070707 (Beckmann et al., GCN
6605; Gotz et al., GCN 6607) using FORS1 on the VLT telescope about 11
hours after the trigger time. We obtained 20 minutes of R-band imaging.
Inside the refined INTEGRAL error circle (Gotz et al., GCN 6607) we do
not detect any obvious afterglow candidate down to the depth of the
DSS image. Our 3-sigma limiting magnitude is R=25.7.
Further observations are planned. We acknowledge the ESO staff for
reliable support.
This message can be cited.
-------------------------------------------------
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GCN Circular 6610
Subject
Swift XRT observation of GRB 070707
Date
2007-07-08T18:53:29Z (18 years ago)
From
Andy Beardmore at U Leicester <apb@star.le.ac.uk>
A.P. Beardmore, K.L. Page (U. Leicester) and A. Parsons (GSFC) report on
behalf of the Swift XRT team:
On 2007 Jul 08 00:57:50UT the Swift XRT started observing the field of
the INTEGRAL burst GRB 070707 (Beckmann et al., GCN 6606; Gotz et al.,
GCN 6607). In a 3.8ks exposure photon counting mode image taken from
31.8 ks to 54.1 ks after the trigger, we detect a source at
RA, Dec = 267.7437, -68.9242, which is
RA(J2000) = 17h 50m 58.49s
Dec(J2000) = -68d 55m 27.0s
with an uncertainty of 5.4 arcsec (90% containment). This is 36.3 arcsec
from the position reported by Gotz et al. (GCN 6607), and within their
error circle.
Using a circular extraction region of 10 pixels radius, we observe 26
total counts. Together with an estimated background level of 1.0
count in the extraction region, we find the 99.73% Bayesian
confidence level on the source count rate is 0.003 to 0.011 count s^-1.
However, with such a limited number of photons, it is impossible to
say at this stage whether the source is fading and if this is the X-ray
counterpart to the GRB.
This circular is an official product of the Swift XRT team.
GCN Circular 6611
Subject
Swift/UVOT Observations of GRB070707
Date
2007-07-08T18:56:30Z (18 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL-UCL) and A. Parsons (GSFC) report on the behalf of the
Swift UVOT team:
The Swift/UVOT observed the field of INTEGRAL burst, GRB070707 starting 8.8hrs
after the INTEGRAL trigger (Beckmann et al. 2007, GCN Circ. 6606). We do not
find any new source in any of the UVOT observations inside the refined INTEGRAL
error circle (Gotz et al. 2007, GCN Circ. 6607) or XRT error circle (Beardmore
et al. 2007, GCN 6610)
The 3-sigma upper limits for detecting a source inside the refined XRT
error circle in the initial data products are:
Filter T_mid(s) Exp(s) Mag (3-sigma upper limit)
-------------------------------------------------------
V 53885 543 19.7
B 31910 324 20.6
U 47905 97 19.5
UVW1 47149 964 20.3
UVM2 39328 1190 20.5
UVW2 53182 1800 20.5
-----------------------------------------------------------------
where T_mid is the weighted mid time of the coadded exposure. The values
quoted above are not corrected for the expected Galactic extinction
corresponding to a reddening of E_{B-V} = 0.08 mag in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 6612
Subject
GRB 070707: object inside XRT error circle
Date
2007-07-08T19:10:28Z (18 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
S. Piranomonte (INAF-OAR), S. Vergani (DIAS-DCU), P. D'Avanzo & G.
Tagliaferri (INAF-OABr) report on behalf of the MISTICI collaboration:
Following the detection by Swift/XRT (Beardmore et al., GCN 6610) of GRB
070707 (Beckmann et al., GCN 6605; Gotz et al., GCN 6607), we have
inspected our VLT R-band images (D'Avanzo et al., GCN 6609).
Inside the XRT error box, we find a single source with R ~ 23.0
(calibrated using archival instrumental zeropoints), at the coordinates
(J2000, 0.5" error):
RA(2000) = 17:50:58.55
Dec(2000) = -68:55:27.2
At the present stage, we cannot yet assess the relationship of this
source with GRB 070707. Further observations are planned.
This message can be cited.
GCN Circular 6613
Subject
GRB 070707: optical afterglow
Date
2007-07-09T04:20:54Z (18 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
P. D'Avanzo (INAF-OABr), S. Piranomonte (INAF-OAR) & S. Vergani
(DIAS-DCU) on behalf of the MISTICI collaboration L. Christensen, P.
Amico (ESO) report:
We observed again the field of the short/hard GRB 070707 (Beckmann et
al., GCN 6605; Gotz et al., GCN 6607) with the ESO-VLT in imaging mode.
Observations have been carried out around Jul 09.08 UT in the R band
with the FORS1 camera.
A comparison with the images of our previous observing run (D'Avanzo et
al., GCN 6609) revealed that the object inside the XRT error box
(Beardmore et al., GCN 6610) reported by Piranomonte et al. (GCN 6612)
faded of about 0.7 +/- 0.1 mag. We thus propose this object as the
optical afterglow of GRB 070707.
Further observations are planned. We acknowledge the ESO staff for
reliable support.
This message can be cited.
GCN Circular 6615
Subject
Konus-Wind observation of GRB 070707
Date
2007-07-09T15:27:11Z (18 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
and T. Cline on behalf of the Konus-Wind team report:
The short GRB 070707 (Beckmann et al., GCN 6605; Gotz et al., GCN 6607)
triggered Konus-Wind at T0=58122.823 s UT (16:08:42.823).
The Konus-Wind light curve shows a multipeaked structure
with a total duration of ~1 s.
As observed by Konus-Wind the burst
had a fluence of 1.41(-1.07, +0.16)x10^-6 erg/cm2,
and a 16-ms peak flux measured from T0-0.016 s
8.1(-6.7, +2.9)x10^-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The spectrum of the most intense part of the burst
(from T0 to T0+0.256) is well fitted
(in the 20 keV - 2 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep)
with alpha = 0.57 (-0.59, +0.43)
and Ep = 427(-144, +374) keV (chi2 = 13/19 dof).
Thus, this burst is classified as a short hard GRB.
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/GRB070707_T58122/
GCN Circular 6626
Subject
GRB 070707: Swift-XRT follow-up observations
Date
2007-07-15T00:42:06Z (18 years ago)
From
Andy Beardmore at U Leicester <apb@star.le.ac.uk>
A.P. Beardmore (U. Leicester) and A. Parsons (GSFC) report on behalf of
the Swift-XRT team:
The Swift XRT obtained further follow-up observations of
GRB 070707 (Beckmann et al., GCN 6606; Gotz et al., GCN 6607). In an
11.1 ks exposure photon counting mode image taken from 325.1 ks to
516.6 ks after the trigger, and using the same 10 pixel radius extraction
region as before, we find a 3 sigma upper limit to the observed count
rate of 0.0011 count/s. When compared with the initial XRT detection
(Beardmore et al., GCN 6610) of 0.0066 +/- 0.0013 count/s (where the
error bar is a 1 sigma estimate) we conclude the source has faded and
that it was the X-ray counterpart to the GRB.
An absorbed powerlaw fit to the photon energy distribution of the
source observed during the first XRT observation (from 31.8 ks to
54.1 ks after the trigger), using Cash statistics and with the NH fixed
at the (Dickey and Lockman) galactic value of 6e20cm^-2, gave a powerlaw
index of 2.7 +/- 0.6. The observed 0.3-10 keV flux was
(2.4 +2.0 -1.4)e-13 ergs cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.