GRB 120711A
GCN Circular 13513
Subject
GRB120711A: Planned XMM-Newton observation
Date
2012-07-24T15:22:35Z (13 years ago)
From
Norbert Schartel at XMM-Newton/ESA <too@xmm.esac.esa.int>
XMM-Newton will observe GRB120711A at location
(RA=06h 18m 42.79s, DEC=-70d 59' 56.6", J2000),
starting at 20:01:44 UT, on July 28, 2012,
for an exposure of 28000 seconds.
XMM-Newton SOC
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GCN Circular 13485
Subject
GRB 120711A: ATCA 34GHz final observations (upper limit)
Date
2012-07-17T01:19:37Z (13 years ago)
From
Paul Hancock at U of Sydney <hancock@physics.usyd.edu.au>
P. Hancock, T. Murphy, B. Gaensler, M. Bell, D. Burlon (University of
Sydney/CAASTRO), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI)
We observed GRB120711A (GCN 13434) with the Australia Telescope
Compact Array at 34GHz for 64 minutes centered on 21:42UT Jul 16 2012
(T0+3.78days) in clear weather.
We detect no radio source at the location of the GRB (GCN 13430) and
place a 3sigma upper limit of 96uJy on the flux of an afterglow.
No further observations are planned.
These observations were obtained as part of ATCA project C2689. We
thank the observatory staff for their support and scheduling the
observations. The Australia Telescope is funded by the Commonwealth of
Australia for operation as a National Facility managed by CSIRO.
GCN Circular 13468
Subject
GRB 120711A: INTEGRAL/SPI observations
Date
2012-07-14T12:08:26Z (13 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
L. Hanlon (UCD), A. Martin-Carrillo (UCD), X.-L. Zhang (MPE) and A. von Kienlin
(MPE) report:
"The bright and long GRB detected by IBAS in the INTEGRAL IBIS/ISGRI data
at 02:44:48 UT on July 11th 2012 (Gotz et al., GCN 13434 ) was also observed
by the Spectrometer SPI onboard INTEGRAL, in addition to the detection by
its anticoincidence shield (SPI-ACS). The event was located in the field
of view of SPI, which allows spectral analysis of this event.
The light curve from SPI events starts with a precursor at 02:44:50 UT followed
by a bright double peaked main emission phase at 02:45:55 UT with a duration
of about 50 sec. The emission during the main peak is seen up to ~3 MeV.
We searched for the faint and soft emission after the main outburst reported by
E. Bozzo et al. (GCN 13435) and S. Golenetskii et al. (GCN 13446).
We find a weak tail in the 20 to 100 keV energy range, lasting for about 800 s
after the main emission phase .
The time-integrated spectrum of the main emission phase is well fitted (in
the 20 keV - 3 MeV range) by an exponential cutoff powerlaw model, with
photon index = 1.00+/-0.03 and an high energy cutoff at 1200 +/- 200 keV.
The fluence during the 50 seconds main emission phase in the 20-1000 keV
range is (2.26 +/- 0.04)E-4 erg/cm^2.
The spectral analysis results presented above are preliminary."
GCN Circular 13463
Subject
GRB 120711A: ATCA 34GHz further observations (upper limit)
Date
2012-07-14T01:29:01Z (13 years ago)
From
Paul Hancock at U of Sydney <hancock@physics.usyd.edu.au>
P. Hancock, T. Murphy, B. Gaensler, M. Bell, D. Burlon (University of
Sydney/CAASTRO), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI)
We observed GRB120711A (GCN 13434) with the Australia Telescope
Compact Array at 34GHz for 60 minutes centered on 23:18UT Jul 13 2012
(T0+2.85days).
We detect no radio source at the location of the GRB (GCN 13430) and
place a 3sigma upper limit of 230uJy on the flux of an afterglow.
Further observations are planned.
These observations were obtained as part of ATCA project C2689. We
thank the observatory staff for their support and scheduling the
observations. The Australia Telescope is funded by the Commonwealth of
Australia for operation as a National Facility managed by CSIRO.
GCN Circular 13452
Subject
GRB 120711A: Fermi LAT Detection
Date
2012-07-12T02:03:05Z (13 years ago)
From
Daniel Kocevski at SLAC <dankocevski@gmail.com>
Daniel Kocevski (Stanford Univ.) and Giacomo Vianello (CIFS/SLAC), Nicola Omodei (Stanford Univ.), and Seth Digel (SLAC) report on behalf of the Fermi LAT Team:
Fermi-LAT has detected high energy emission from the bright GRB 120711A in ground analysis. The GRB triggered the Fermi-GBM on July 11th, 2012 at 02:44:53.29 UTC (trigger 363667496/120711115, Gruber et al. GCN 13437) and was bright enough to result in a spacecraft autonomous repoint.
At the time of the GBM trigger, the angle between the GRB position and the LAT bore-sight was 134.4 degrees for the duration of the prompt emission, and remained outside the Fermi-LAT nominal field of view for an additional ~600 seconds.
A preliminary maximum-likelihood analysis of the E>75MeV P7TRANSIENT_V6 LAT data centered on the XRT position reported by Beardmore et al. (GCN 13442) generated for the interval T0+600s to T0+1100s revealed a significant transient source, with a spectrum well described by a power law of index -2.0 +/ 0.3 (68% C.L. statistical only). These results are in agreement with those found by Tam et al. (GCN 13444). Using the data covering T0+600s to T0+1100s, we obtained the best LAT on-ground localization of:
RA(J2000) = 94.7 deg
Dec(J2000) = -70.9 deg
with an error radius of 0.16 deg (90% containment, statistical error only), which is 0.09 deg from the XRT position, and 0.07 deg from the position reported by Tam et al. (GCN 13444).
We note that this position is ~1.4 degrees away from the known variable gamma-ray source 2FGL J0601.1-7037, which has been associated with the blazar PKS 0601-70. In order to understand if the observed excess can be due to a brightening of the blazar we considered two nested models for our data, one including just the blazar, and one including both the blazar and a new source (the GRB). Our data favor the latter model, with the fit converging to a solution with a negligible contribution from the blazar, as expected from the mean flux reported in the Fermi 2FGL catalog (Nolan et al., 2012). An analysis using E>75MeV P7TRANSIENT_V6 data covering an interval before the burst (T0-6000s to T0-2000 s) shows no significant emission at the location of the blazar. Thus, 2FGL J0601.1-7037 is unlikely to be the source of the excess.
We caution against the use of data after ~T0+2600 s, because of a large Zenith angle of the GRB, potentially resulting in a strong contamination from terrestrial gamma-rays originating from charged particle interactions with Earth's atmosphere.
The Fermi-LAT point of contact for this burst is Daniel Kocevski
(kocevski@stanford.edu)
GCN Circular 13451
Subject
GRB 120711A: ATCA 34GHz upper limit
Date
2012-07-12T01:53:15Z (13 years ago)
From
Paul Hancock at U of Sydney <hancock@physics.usyd.edu.au>
P. Hancock, T. Murphy, B. Gaensler, M. Bell, D. Burlon (University of
Sydney/CAASTRO), A. de Ugarte Postigo (Dark Cosmology / IAA)
We observed GRB120711A (GCN 13434) with the Australia Telescope
Compact Array at 34GHz for 26 minutes centered on 21:37UT Jul 11 2012
(T0+18.9hours) in stormy weather.
We detect no radio source at the location of the GRB (GCN 13430) and
place an upper limit of 3.6mJy on the flux of an afterglow.
Further observations are planned.
These observations were obtained as part of ATCA project C2689. We
thank the observatory staff for their support and scheduling the
observations. The Australia Telescope is funded by the Commonwealth of
Australia for operation as a National Facility managed by CSIRO.
GCN Circular 13448
Subject
GRB 120711A: Swift/UVOT Observations
Date
2012-07-11T21:55:34Z (13 years ago)
From
Alice Breeveld at MSSL-UCL <aab@mssl.ucl.ac.uk>
A. A. Breeveld (MSSL-UCL) and M. J. Page (MSSL-UCL) report on behalf of
the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120711A
8216 s after the INTEGRAL trigger (Gotz et al., GCN Circ. 13434).
No significant optical afterglow consistent with the position given in
Lacluyze et al. (GCN_Circ. 13430) is detected in the initial UVOT
exposures. However, in the U filter, the source may be detected at this
position with a significance of 2 sigma. The possible detection is
included in the table.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial
exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
b 8464 8480 16 >18.7
u 8380 8459 79 >19.4
w1 8216 8375 157 >19.8
u 8380 8459 79 19.6 � 0.5 (2sig)
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.08 in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 13446
Subject
Konus-Wind observation of GRB 120711A
Date
2012-07-11T18:35:12Z (13 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The long hard intense GRB 120711A
(detected by the INTEGRAL/IBAS Gotz et al., GCN 13434;
MAXI/GSC detection: Serino et al., GCN 13436;
Fermi/GBM trigger 363667496/120711115: Gruber & Palassa, GCN 13437;
Fermi/LAT detection: Tam, Li & Kong, GCN 13444)
triggered Konus-Wind at T0=09955.810s UT (02:45:55.810)
The light curve starts with a precursor at ~T0-65s followed by
a strong hard double pulse lasting from ~T0-3 s to ~T0+50 s.
Several short (100 - 200 ms) bright spikes are well detected
over the general burst light curve in the ~T0+30 s to ~T0+40 s
time interval.
A a weak decaying emission tail in the soft energy channel
G1(25-90 keV) is detectable till at least ~T0+400s.
The emission during the main phase of the event is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB120711_T09955/
As observed by Konus-Wind the burst
had a fluence of 3.8(-0.2,+0.2)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+32.576 s,
of 3.6(-0.4,+0.4)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(measured from T0 to T0+46.336 s)
is best fit in the 20 keV - 10 MeV range
with the GRB (Band) model, for which:
the low-energy photon index alpha = -0.97 (-0.02, +0.02),
the high energy photon index beta = -2.7 (-0.3, +0.2),
the peak energy Ep = 1060(-60, +60) keV,
chi2 = 95.7/87 dof.
The spectrum at the maximum count rate
(measured from T0+30.208 to T0+34.560 s)
is best fit in the 20 keV - 10 MeV range
with the GRB (Band) model, for which:
the low-energy photon index alpha = -0.93 (-0.04, +0.04),
the high energy photon index beta = -2.5 (-0.5, +0.3),
the peak energy Ep = 1400(-160, +170) keV,
chi2 = 85.5/87 dof.
Assuming the likely GRB redshift of z=1.405 (Tanvir et al., GCN 13441)
and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27,
Omega_Lambda = 0.73:
the isotropic energy release E_iso is (1.95 � 0.1)x10^54 erg,
the isotropic peak luminosity L_iso_max is (4.5 � 0.5)x10^53 erg/s,
and Ep_rest is (2550 � 150) keV.
All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.
GCN Circular 13444
Subject
GRB 120711A: Fermi LAT detection
Date
2012-07-11T17:29:37Z (13 years ago)
From
Thomas P.H. Tam at Nat.Tsing Hua U. <grbtom@gmail.com>
P.H.T. Tam, K.L. Li and A.K.H. Kong (NTHU) report:
We report on the Fermi Large Area Telescope (LAT) detection of >100 MeV
gamma-ray emission from the direction of the bright GRB 120711A, which
triggered INTEGRAL (Gotz et al., GCN 13434), MAXI/GSC (Serino et al., GCN
13436), and Fermi/GBM (Gruber et al., GCN 13437). The GRB position was
outside the LAT field of view at the GRB onset (c.f. GCN 13437). However,
gamma-ray emission up to around 2 GeV was detected from the GRB direction
from 0.8 ks to ~7 ks after the burst. Such duration is one of the longest
ever observed for a GRB in GeV domain.
Using the data obtained from the above period, an unbinned likelihood
analysis resulted in a detection significance of ~7 sigma, and a photon
spectral index of -1.8+-0.3. We localized the LAT emission to be at RA, DEC
(J2000 deg) = 94.58, -70.93, with a statistical error of ~0.17 deg (68%
CL), which is compatible with the Swift/XRT position (Beardmore et al., GCN
13442).
GCN Circular 13443
Subject
GRB 120711A: MASTER early OT detection
Date
2012-07-11T15:51:48Z (13 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
H. Levato and C. Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
C. Mallamaci, C. Lopez and F. Podest
Observatorio Astronomico Felix Aguilar (OAFA)
D. Denisenko, A. Kuznetsov, V. Lipunov, E. Gorbovskoy, V. Kornilov,
D. Kuvshinov, A. Belinski, N. Tyurina, N. Shatskiy, P. Balanutsa,
D. Zimnukhov, V.V. Chazov
Lomonosov Moscow State University, Sternberg Astronomical Institute
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V. Sennik
Kislovodsk Solar Station of the Pulkovo Observatory
K. Ivanov, S. Yazev, N.M. Budnev, O. Gres, O. Chuvalaev, V.A. Poleshchuk
Irkutsk State University
V. Yurkov, Yu. Sergienko, D. Varda, E. Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
V. Krushinski, I. Zalozhnich, A. Popov, A. Bourdanov, A. Punanova
Ural Federal University
MASTER-ICATE robotic very wide field cameras (FOV=2x384 square
degrees, D=72mm, f/1.2, 1 pix = 22 arcsec, http://observ.pereplet.ru)
located in Argentina (Observatorio Astronomico Felix Aguilar,
http://93.180.27.230:8080/) were pointed to the
INTEGRAL TRIGGER_NUM 6599 = Fermi TRIGGER_NUM: 363667496
60 sec after INTEGRAL trigger Time (Gotz et al., GCN 13434, Gruber
and Pelassa, GCN 13437) on 2012-07-11 at 02:45:54.107 UT.
Our cameras are continuously imaging the sky with 5 sec exposures.
On our first unfiltered image (5 sec exposure) we have not found any OT.
We see OT (Lacluyze et al., GCN 13430, Zheng et al., GCN 13432, Elliot et
al., GCN 13438, Fugazza et al., GCN 13439 and Tanvir et al., GCN 13441)
on the sum of 4 images obtained between T0+121s and T0+141s with the
unfiltered magnitude 12.5. Nothing is visible at the OT position on
the individual (m_lim = 12.0) and combined (m_lim=13.0) images obtained
before T0+121s and after T0+141s.
This message can be cited.
GCN Circular 13442
Subject
GRB 120711A: Swift-XRT observations
Date
2012-07-11T13:00:00Z (13 years ago)
From
Andy Beardmore at U Leicester <ab271@leicester.ac.uk>
A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:
We have analysed 657 s of XRT data for the INTEGRAL-detected burst: GRB
120711A (Gotz et al. GCN Circ. 13434), from 8.3 ks to 20.0 ks after the
INTEGRAL trigger. The data comprise 269 s in Windowed Timing (WT) mode
with the remainder in Photon Counting (PC) mode. An X-ray source is
detected within the INTEGRAL error circle. Using 336 s of PC mode data
and 1 UVOT images, we find an enhanced XRT position (using the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue):
RA, Dec = 94.67830, -70.99905 which is equivalent to:
RA (J2000): 06h 18m 42.79s
Dec(J2000): -70d 59' 56.6"
with an uncertainty of 1.7 arcsec (radius, 90% confidence). This
position is 29 arcsec from the INTEGRAL position and 0.3 arcsec from
the Skynet/PROMPT position (LaCluyze et al. GCN Circ. 13430).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.59 (+0.16, -0.15).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.15 (+/-0.11). The
best-fitting absorption column is 3.6 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 7.9 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 1.80 (+0.25, -0.23)
and a best-fitting absorption column of 2.4 (+0.9, -0.8) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.5 x 10^-11 (6.2 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.4 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 7.9 x 10^20 cm^-2
Excess significance: 3.2 sigma
Photon index: 1.80 (+0.25, -0.23)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020223.
This circular is an official product of the Swift-XRT team.
GCN Circular 13441
Subject
GRB 120711A Gemini-S likely redshift
Date
2012-07-11T12:46:35Z (13 years ago)
From
Nial Tanvir at U.Leicester <nrt3@star.le.ac.uk>
N. R. Tanvir, K. Wiersema (U. Leicester), A. J. Levan (U. Warwick),
D. Fox (Penn State), A. Fruchter (STScI) and D. Krogsrud (Gemini)
report on behalf of a larger collaboration:
We observed the afterglow of GRB 120711A (Gotz et al. GCN 12434;
Lacluyze et al. GCN 12430) using the GMOS-S spectrograph on Gemini-South.
Observations began at 2012-7-11 10:08 UT, about 7.5 hr post-burst.
The data were obtained at high air-mass and on the boundary of twilight,
so the signal-to-noise is rather poor. Nevertheless,
in the spectrum we identify lines of MgII (2797/2804A) and
FeII (2374/2383/2587/2600A) at a common redshift of z=1.405.
This therefore provides a robust lower-limit to the redshift of the GRB.
Furthermore, given the lack of other absorption features, in particular
any matching a redshift z~3 (Elliott et al. GCN 13438), we tentatively
identify z=1.405 as the most likely GRB redshift.
GCN Circular 13439
Subject
GRB 120711A: REM NIR early time detection
Date
2012-07-11T11:31:46Z (13 years ago)
From
Stefano Covino at Brera Astronomical Observatory <stefano.covino@gmail.com>
D. Fugazza, S. Covino, A. Rossi on behalf of the REM team report:
We imaged the field of GRB120711A (Gotz et al., GCN 13434 and Bozzo et al., GCN 13435) with the NIR camera (the optical camera is at present under maintenance) of the REM 60cm telescope located at La Silla.
The bright optical counterpart reported in GCN 13430 (Lacluyze et al.), GCN 13432 (Zheng et al.) and GCN 13438 (Elliot et al.) is well detected in the NIR at a peak magnitude of H = 11.90 + 0.05 between 2-4 minutes after the burst. The source was then fading rapidly remaining approximately at the same magnitude, H~13, for several more minutes.
Data have been calibrated by isolated not-saturated 2MASS stars in the field.
GCN Circular 13438
Subject
GRB 120711A: GROND photometric redshift
Date
2012-07-11T11:11:49Z (13 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
J. Elliott (MPE Garching), S. Klose (TLS Tautenburg), and J. Greiner (MPE
Garching) report on behalf of the GROND team:
We observed the field of GRB 120711A (INTEGRAL trigger 6599: Gotz et al.,
GCN 13434; Bozzo et al., GCN 13435; MAXI/GSC detection: Serino et al., GCN
13436; Fermi/GBM trigger 363667496 / 120711115: Gruber & Pelassa, GCN
13427) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP
120, 405) mounted at the 2.2m MPG/ESO telescope at La Silla Observatory
(Chile).
Observations started on July 11, 08:34 UT, 5.8 hrs after the trigger as
soon the location became visible at La Silla. The afterglow (Lacluyze et
al., GCN 13430, 13433; Zheng, GCN 13432) is clearly detected in all bands.
For an exposure of 8 min in JHK and 7.66 min in g'r'i'z', at an average
airmass of 2.5 and an average seeing of 2".0, we measure the following
preliminary AB magnitudes
g' = 20.9 +/- 0.1
r' = 20.2 +/- 0.1
i' = 19.6 +/- 0.1
z' = 19.4 +/- 0.1
J = 18.6 +/- 0.1
H = 18.2 +/- 0.1
K = 18.0 +/- 0.1
The SED, after correction for Galactic reddening along the line of sight
(E(B-V)=0.09 mag; Schlegel et al. 1998), can be described by a power law
(beta ~ 1.4) with a reduced flux in the g-band, suggesting a photometric
redshift of about 3. We note that also the PROMPT afterglow light curve
(http://skynet.unc.edu/grb/grb120711a.png) supports a drop-out in the blue
bands.
Magnitudes are derived based on GROND zeropoints (g'r'i'z') and 2MASS
stars (JHK).
GCN Circular 13437
Subject
GRB 120711A: Fermi GBM observation
Date
2012-07-11T10:18:39Z (13 years ago)
From
David Gruber at MPE <dgruber@mpe.mpg.de>
David Gruber (MPE) and V�ronique Pelassa (UAH)
report on behalf of the Fermi GBM Team:
"At 02:44:53.29 UT on 11 July 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 120711A (trigger 363667496 / 120711115).
which was also detected by the INTEGRAL/IBAS
(Gotz et al. 2012, GCN 13434).
The GBM on-ground location is consistent with the INTEGRAL position.
The angle from the Fermi LAT boresight is 140 degrees.
Moreover, this burst was bright enough to result in a Fermi spacecraft
autonomous rapid repoint (ARR) maneuver.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of a precursor which is
followed by a hard, main emission after ~ 50 s, lasting for
another ~ 50 s. The T90 is about 44 s (50-300 keV).
The time-averaged spectrum from T0-1 s to T0+131 s is
best fit by a Band function with Epeak = 973 +/- 35 keV,
alpha = -0.94 +/- 0.01, and beta = -2.40 +/- 0.04.
This spectrum is typical of a bright, hard GRB, and would be
highly unusual for an X-ray transient (Bozzo et al. 2012, GCN 13435).
The event fluence (10-1000 keV) in this time interval is
(1.942 +/- 0.002)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+95 s in the 10-1000 keV band
is 26.7 +/- 0.6 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 13436
Subject
GRB 120711A: MAXI/GSC detection
Date
2012-07-11T10:14:08Z (13 years ago)
From
Mikio Morii at Tokyo Inst Tech <morii@hp.phys.titech.ac.jp>
M. Serino (RIKEN), M. Morii(Tokyo Tech), S. Nakahira (JAXA),
N. Kawai, R. Usui, K. Ishikawa, T. Yoshii (Tokyo Tech),
S. Ueno, H. Tomida, M. Ishikawa (JAXA),
T. Mihara, M. Sugizaki, T. Yamamoto, J. Sugimoto, M. Matsuoka (RIKEN),
A. Yoshida (AGU),
H. Tsunemi, M. Kimura (Osaka U.),
H. Negoro, M. Nakajima, M. Asada, H. Sakakibara, N. Serita (Nihon U.),
Y. Ueda, K. Hiroi, M. Shidatsu, R. Sato (Kyoto U.),
Y. Tsuboi, M. Higa (Chuo U.)
M. Yamauchi, Y. Nishimura, T. Hanayama, K. Yoshidome (Miyazaki U.),
K. Yamaoka (Waseda U.)
report on behalf of the MAXI team:
MAXI/GSC triggered at 2012-07-11T02:45:12 UT on a bright uncatalogued X-ray transient source.
The transient emission lasted at least 50 seconds
within the 67 second long triangular transit response of
MAXI/GSC.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (94.04 deg, -71.09 deg) = (06 16 10,$B!!(B-71 05 37)(J2000)
with a 90% C.L. statistical error of 12 arcmin and an additional systematic uncertainty of 0.1 deg (90% containment radius).
Without assuming the source constancy, we obtain a rectangular
error box (90%C.L.) with the following corners:
(R.A., Dec) = (+94.86 deg, -70.99 deg) = (06 19 29, -70 59 26)(J2000)
(R.A., Dec) = (+94.93 deg, -71.21 deg) = (06 19 44, -71 12 23)(J2000)
(R.A., Dec) = (+91.53 deg, -71.22 deg) = (06 06 06, -71 13 27)(J2000)
(R.A., Dec) = (+91.52 deg, -71.01 deg) = (06 06 05, -71 00 26)(J2000)
This error region includes the position of GRB 120711A
reported by Lacluyze et al. (GCN #13430) and Gotz et al. (GCN #13434).
Fixing the source position to that of GRB 120711A,
we obtained the light curve corrected with the transit response
within the GSC scan.
It was variable within the scan, and
the peak flux was 610 +- 130 (mCrab, 2-20 keV) on 2012-07-11 02:44:54 UT.
GCN Circular 13435
Subject
GRB 120711A: a possible X-ray transient
Date
2012-07-11T09:59:40Z (13 years ago)
From
Diego Gotz at CEA <diego.gotz@cea.fr>
E. Bozzo (ISDC, Versoix), D. Gotz (CEA-Saclay), S. Mereghetti (IASF Milano), C. Ferrigno, L. Gibaud (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
A refined analysis of a larger IBIS/ISGRI dataset corresponding to the GRB120711A (GCN 13434), revealed a faint emission, lasting for at least ~1000s, after the main outburst.
Being this duration unusual for a GRB, we are at present unable to rule out a different nature for this event (e.g. a bright transient in the direction of the LMC).
The event has been detected also using the SPI Anti Coincidence System (ACS) on board of INTEGRAL which is not saturated and shows a highly structured light-curve at the peak http://www.isdc.unige.ch/~bozzo/lightcurve.dat .
Further observations are encouraged.
[GCN OPS NOTE(11jul12): Per author's request, the 13432 reference was changed to 13434.]
GCN Circular 13434
Subject
GRB 120711A: an bright long GRB detected with INTEGRAL
Date
2012-07-11T04:28:05Z (13 years ago)
From
Diego Gotz at CEA <diego.gotz@cea.fr>
D. Gotz (CEA-Saclay), S. Mereghetti (IASF Milano), E. Bozzo, C. Ferrigno, L. Gibaud (ISDC, Versoix), and J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:
a long and bright GRB has been detected by IBAS in the IBIS/ISGRI data at 02:44:48 UT on July 11th 2012. The GRB lasts approximately 135 s and its refined coordinates are
RA: 94.703 [degrees]
DEC: -71.001 [degrees]
with an uncertainty of 1.1 arc min (90% c.l.).
A preliminary spectral analysis yields a fluence of 1.6e-5 erg/cmsq in the 20-200 keV energy band and a peak flux over 1 s of 10 photons/cmsq/s in the same energy band. Please note that due to telemetry saturation at satellite levels there values are only lower limits.
We note that our position is consistent with the optical transient reported by Lacluyze et al. (CGN 13430).
A plot of the light curve has been posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
This message can be cited.
GCN Circular 13433
Subject
Continued Skynet/PROMPT observations of GRB120711A
Date
2012-07-11T04:14:24Z (13 years ago)
From
Aaron LaCluyze at U.North Carolina <lacluyze@email.unc.edu>
A. Lacluyze, J. Haislip, K. Ivarsen, D. Reichart, J. Moore, H. T.
Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E.
Speckhard, A.Trotter, and J. A. Crain report:
Skynet continued to observe the field of GRB120711A (INTEGRAL trigger 6599,
GCN 13430 and 13432.) A preliminary light curve in B, V, and R, calibrated
to ~5 USNO B1.0 stars can be found at:
http://skynet.unc.edu/grb/grb120711a.png
GCN Circular 13432
Subject
GRB 120711A: ROTSE-III confirm of Optical Counterpart
Date
2012-07-11T03:43:34Z (13 years ago)
From
Weikang Zheng at U.of Michigan <zwk@umich.edu>
W. Zheng (U Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded
to GRB 120711A (Integral trigger 6599). The first image was at 02:45:54.4
UT, 59.1 s after the burst (5.4 s after the GCN notice time). We also
detected the suggested optical afterglow found by Skynet/PROMPT (Lacluyze et
al., GCN 13430). The afterglow is detected in our first co-add image with
Mag ~14.2 (mean time of ~60s) and decayed fainter than 15.8 mag in the
second co-add (mean time of 460s). The unfiltered images are calibrated
relative to USNO A2.0.
Continuing observations are in progress.
GCN Circular 13430
Subject
Skynet/PROMPT Observations of GRB120711A
Date
2012-07-11T03:23:16Z (13 years ago)
From
Aaron LaCluyze at U.North Carolina <lacluyze@email.unc.edu>
A. Lacluyze, J. Haislip, K. Ivarsen, D. Reichart, J. Moore, H. T.
Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E.
Speckhard, A.Trotter, and J. A. Crain report:
Skynet observed the field of GRB12711 (INTEGRAL trigger 6599) in B, V, and
R starting 37 seconds after the burst. Although no afterglow was detected
in the initial exposures, a transient source was detected at 06:18:42.839
-70:59:56.78 (J2000). The source rapidly brightened, peaking at roughly
112 seconds after the trigger. Preliminary peak magnitudes, calibrated to
~5 UNSO B1.0 stars are as follows:
Time Tel Filt Mag 1sigERR
112 P4 R 12.117 0.008
113 P1 V 12.593 0.014
116 P3 B 14.061 0.014
The post-peak temporal index is estimated to be -2.1, suggesting a reverse
shock.
Further observations are ongoing.