- GCN Circular #7697
Subject: GRB 080507: Gamma Ray Burst Localization by SuperAGILE
I. Lapshov, E. Costa, E. Del Monte, I. Donnarumma, Y. Evangelista,
M. Feroci, 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, M. Fiorini, 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. Cattaneo (INFN Pavia), 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,
F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team,
report:
"SuperAGILE detected and localized a gamma ray burst
on May 7th, at 07:45:00 UT. The event was detected during the
passage of the AGILE spacecraft through the South Atlantic
Anomaly and this caused the non-detection by the automatic
burst search procedures, and the delayed identification thereof.
The observed duration in the 20-60 keV energy range is about 40 seconds,
with a multi-peaked structure.
The burst position was reconstructed as (RA, Dec) (233.721 deg,
56.424 deg), which is:
RA(J2000) = 15h 34m 53.11s
Dec(J2000) = 56d 25' 27.3"
with an uncertainty of 3' radius. The given uncertainty accounts
for both the statistical and systematic errors.
This position lies approximately 100 arcsec from the galaxy NGC 5969.
The telemetry of the AGILE Gamma Ray Imager (GRID) is disabled
during the passage through the South Atlantic Anomaly, thus no
GRID data are available for this GRB."
This message may be cited.
- GCN Circular #7699
V. Mangano, B. Sbarufatti (INAF-IASF PA), J. Kennea (PSU),
and W. H. Baumgartner (GSFC/UMBC)
report on behalf of the Swift-XRT team:
Swift started a ToO observation of GRB 080507 (Lapshov et al.,
GCN Circ. 7697) today at 14:05 UT.
We have analysed the first 2.5 ks of PC data and found a bright
uncatalogued source at RA, Dec = 233.68085, 56.43520
which is equivalent to:
RA (J2000): 15 34 43.40
Dec (J2000): +56 26 06.7
with an uncertainty of 2.5 arcsec (radius, 90% confidence;
astrometrically corrected X-ray position).
This is 90 arcsec from the SuperAGILE position.
We also found a second uncatalogued faint source at
RA, Dec = 233.662500, 56.420972 (118 arcsec from the
SuperAGILE position) and a third faint source at
RA, Dec = 233.612083, 56.428500 (217 arcsec from the
SuperAGILE potition), likely the counterpart of
SDSS J153426.68+562545.8.
At the moment data are not enough to say if these sources
are fading.
This is an official product of the Swift-XRT team
- GCN Circular #7701
D. A. Kann, C. Hoegner, S. Ertel and S. Schulze (TLS Tautenburg) report:
We observed the field of the AGILE GRB 080507 (Lapshov et al., GCN 7697)
with the Tautenburg 1.34m Schmidt telescope after twilight in good
conditions. We obtained 12 usable 180 second images in the Rc band, with a
mid-exposure time of 1.54 days after the GRB.
At the position of the brightest X-ray source (Mangano et al., GCN 7699),
we detect an optical source that is not visible in the DSS (but is
significantly below the limiting magnitude) or the SDSS (which has a
comparable limiting magnitude to our image). We consider this the optical
afterglow of GRB 080507 due to the coincidence with the bright X-ray
source. At the moment, we can't make any claims of variability.
Assuming the USNOB1.0 star just to the north of the afterglow position, at
R.A. = 15 34 43.7, Dec. = +56 26 21, has R1 = 14.96 (R2 = 15.08), we find
a magnitude for the afterglow of:
time (days) Rc dRc
1.5383 22.10 0.11
Further follow-up is encouraged to confirm a fading nature for this
source.
We note that the error circle of the second faint X-ray source at R.A. =
233.662500, Dec. = 56.420972 (Mangano et al., GCN 7699) also contains an
optical source clearly visible in the SDSS and in our images, implying
that this is a persistent source.
This message may be cited.
- GCN Circular #7702
A. A. Breeveld (MSSL/UCL) and W. H. Baumgartner (GSFC/UMBC)
on behalf of the Swift/UVOT team.
The Swift Ultra-Violet/Optical Telescope (UVOT) started a ToO
observation of GRB 080507 (Lapshov et al., GCN Circ. 7697) 109312s
after the AGILE trigger. At the position of the afterglow candidate
seen in the Tautenburg telescope (Kann et al. GCN Circ. 7701), which
also corresponds to the brightest source in the Swift XRT (V. Mangano
et al. GCN Circ. 7699), the UVOT has a very faint source that does not
appear in DSS or SDSS. It is only detectable in summed white images,
but does NOT appear to be fading.
The limiting magnitudes for the initial exposure and detections in
summed images are as follows:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 109312 109526 211.4 >21.3 (UL)
white 109312 111881 2462.3 22.6 +/- 0.4 (3 sig)
white 111881 116511 1355.3 22.1 +/- 0.3 (3.8 sig)
The values quoted above are in the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) and are not corrected for galactic
reddening.
- GCN Circular #7705
D. A. Kann, C. Hoegner, R. Filgas and S. Klose (TLS Tautenburg) report:
We observed again the location of the candidate afterglow (Kann et al.,
GCN 7701) of the AGILE GRB 080507 (Lapshov et al., GCN 7697), which was
also detected as a bright X-ray source (Mangano et al., GCN 7699). We
obtained 20 x 180 sec images in the R band under excellent atmospheric
conditions but with elevated sky background due to twilight and the waxing
moon. The resulting stacked image is roughly half a magnitude deeper than
the image from the first epoch (23.5 vs. 23, respectively).
We find that the candidate afterglow has significantly faded over the
course of a day. Using the same comparison star as Kann et al. (GCN 7701),
we find:
time (days) Rc dRc
2.5578 22.69 0.15
We also use SExtractor (Bertin & Arnouts 1996) to derive magnitudes, and
find Rc = 21.95 +/- 0.14 and Rc = 22.65 +/- 0.20 in the first and second
epoch, respectively, in accordance with our other results.
This fading behaviour is in contrast to the plateau phase or even rising
behaviour reported from UVOT White images (Breeveld & Baumgartner, GCN
7702), which may imply a non-monotonic light curve evolution.
With the clear detection of fading, we consider the identification of this
source as the optical afterglow of GRB 080507 as secure.
Finally, we note that GRB 080507 was also detected by INTEGRAL SPI-ACS,
showing a flat-topped structure, with possible multiple peaks, of 40
seconds duration, in full agreement with the AGILE report (Lapshov et al.,
GCN 7697). The public light curve can be found here:
http://isdc.unige.ch/cgi-bin/cgiwrap/~beck/ibas/spiacs/ibas_acs_web.cgi?trigger=2008-05-07T07-44-58.8545-18523-00007-0
This message may be cited.
- GCN Circular #7706
D. A. Perley (UC Berkeley), J. X. Prochaska (UCO/Lick), and J. Hennawi
(UCB) report:
We imaged the field of Super-AGILE GRB 080507 (Lapshov et al., GCN 7697)
with Keck I (+LRIS) during morning twilight starting at 15:03 UT on
2008-05-08 (31.3 hours after the trigger). Four exposures were taken in
g and R filters simultaneously, although due to twilight only the first
two R-band frames were usable.
We detect the optical afterglow reported by Kann et al. (GCN 7701) at a
position of:
RA = 15:34:43.39
Dec = +56:26:08.28
(estimated uncertainty of 0.7")
in R-band. Our magnitude, calibrated to seven USNO-B1.0 stars, is R =
22.20 +/- 0.11 at 1.31 days after the trigger. This supports the
generally non-fading behavior between 1-2 days after burst in
observations from the Swift UVOT (Breeveld et al., GCN 7702) and
Tautenberg (Kann et al.).
For reference, the observed magnitudes of two nearby USNO stars in the
same calibration system are:
15:35:10.99 +56:23:57.02 R = 20.53 +/- 0.02
15:34:47.68 +56:25:16.44 R = 18.63 +/- 0.01
- GCN Circular #7707
V. Mangano, B. Sbarufatti, V. LaParola, P. Romano (INAF-IASF PA)
and W. H. Baumgartner (GSFC/UMBC)
report on behalf of the Swift-XRT team:
Swift started a second ToO observation of GRB 080507 (Lapshov et al.,
GCN Circ. 7697) on May 9th at 17:24 UT.
We have analyzed the 4 ks PC observation, and found that the brightest
uncatalogued source detected during the previous ToO observation
(Mangano et al., GCN Circ. 7699) has decayed from a rate level of
(1.4 +/- 0.2) e-2 counts s-1 to a level of (2.2 +/- 0.7) e-3 counts s-1.
The second uncatalogued source in the SuperAGILE error circle is
still visible at the constant level of (3.0 +/- 1.0) e-3 counts s-1.
We can confirm that the brightest source detected in Mangano et al.,
GCN Circ. 7699 is the X-ray afterglow of GRB 080507, in agreement with
the observation reported by Kann et al. (GCN 7705).
This is an official product of the Swift-XRT team
- GCN Circular #7708
T. Sugasahara, K. Onda, M. Tashiro, Y. Terada, Y. Urata, A. Endo,
N. Kodaka, K. Morigami, W. Iwakiri (Saitama U.),
M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y.E. Nakagawa,
T. Tamagawa (RIKEN), T. Uehara, T. Takahashi, Y. Fukazawa, C. Kira,
Y. Hanabata (Hiroshima U.), T. Enoto, K. Nakazawa,
K. Makishima (Univ. of Tokyo), E. Sonoda, M. Yamauchi, H. Tanaka,
R. Hara (Univ. of Miyazaki), , S. Hong (Nihon U.),
on behalf of the Suzaku WAM team, report:
The long GRB 080507 (SuperAGILE: Lapshov et al., GCN 7697)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers
an energy range of 50 keV - 5 MeV at 07:45:00 UT (=T0). The
observed light curve shows a multi-peaked structure starting at T0,
ending at T0+45s, with a duration (T90) of about 30 seconds.
The fluence in 100 - 1000 keV was 4.1(+0.1,-0.3)*10^-5 erg/cm^2.
The 1-s peak flux measured from T0+2s was 3.5(+0.2,-1.3) photons/cm^2/s
in the same energy range.
A preliminary result shows that the time-averaged spectrum from
T0 to T0+45s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 0.79(+0.26, -0.28), and
Epeak 492(+70, -49) keV (chi^2/d.o.f. = 15.9/23).
All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.
The light curves for this burst are available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
- GCN Circular #7711
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
and T. Cline on behalf of the Konus-Wind team report:
The long GRB 080507 localized by SuperAGILE (Lapshov et al., GCN
7697) triggered Konus-Wind at T0=27902.194 s UT (07:45:02.194).
As observed by Konus-Wind the burst
had a fluence of 5.09(-0.24, +0.26)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+4.960 s
of (3.07 +/- 0.44)x10^-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+47.616 s) 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 = -0.88 +/- 0.06,
and Ep = 423(-33, +38) keV (chi2 = 55.0/61 dof).
Fitting by GRBM (Band) model yields:
the low-energy photon index is alpha = -0.85 +/- 0.07,
the high energy photon index beta < -2.34,
the peak energy Ep = 399(-32, +42) keV (chi2 = 54.6/60 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/GRB080507_T27902/
- GCN Circular #7732
Sorry. GCN 7731 is about GRN 080507, and not 080705.
Poonam
TITLE: GCN CIRCULAR
NUMBER: 7731
SUBJECT: VLA upper limit on GRB 080705
DATE: 08/05/15 17:28:28 GMT
FROM: Poonam Chandra at U Virginia/NRAO
Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf
of the Caltech-NRAO-Carnegie GRB Collaboration:
"We used the Very Large Array to observe the field of view toward
super-AGILE GRB 080507 (GCN 7697) at a frequency of 8.46 GHz at
2008 May 13.14UT.
We do not detect the GRB afterglow at Swift-XRT position (GCN 7699).
The flux density at the afterglow position is 44 49 uJy. T
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."
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