- GCN Circular #9962
Arne Rau (MPE)
report on behalf of the Fermi GBM Team:
"At 04:33:03.97 UT on 29 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090929A (trigger 275891585 / 090929190).
The on-ground calculated location, using the GBM trigger
data, is RA = 51.7, DEC = -7.3 (J2000 degrees,
equivalent to 03h 27m, -07d 18'), with an uncertainty
of 1.3 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 122 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of multiple short peaks
with a duration (T90) of about 8.5 +/- 0.4 s (8-1000 keV).
The time-averaged spectrum from T0+0.002s to T0+4.896s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -0.52 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 610.9 +/- 44.5 keV
(chi squared 439 for 393 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(1.06 +/- 0.03)E-05 erg/cm^2. The 1.822-sec peak photon flux measured
starting from T0+0.002 s in the 8-1000 keV band is 10.9 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
- GCN Circular #9966
J. R. Cummings (GSFC/UMBC) and H. Krimm (GSFC/USRA) on behalf of
the Swift team
The Fermi-GBM burst GRB 090929A (Rau, GCN Circular# 9962) occurred
during a preplanned Swift slew maneuver. A strong source was found
in a mosaic of images from BAT event data, which is often collected
during slews. The source location was RA, Dec = 56.494, -5.952 or
RA (J2000) 03h 45m 57.9s
Dec (J2000) -05d 57' 50"
with an estimated 90% containment error radius of 3 arcmin. The
partial coding was 73-90% during the burst.
We define the trigger time as 04:33:08 UTC. As seen in BAT, the
burst had three progressively weaker peaks, at T+1, T+4, and T+8.
The peak count rate (15-350 keV) was ~18000 counts/sec at T+2 sec.
T90 was about 10 seconds.
A Swift TOO has been requested and approved.
- GCN Circular #9968
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
P. Oleynik, M. Ulanov, and D. Svinkin on behalf of
the Konus-RF team, report:
The bright GRB 090929A (Fermi-GBM trigger trigger 275891585:
Rau, GCN 9962) localized by Swift-BAT (Cummings and Krimm , GCN 9966)
triggered Konus-RF at T0=16384.747 s UT (04:33:04.747).
The burst light curve shows several multipeaked pulses with a total
duration of ~6 s.
As observed by Konus-RF the burst
had a fluence of 1.24(-0.11, +0.12)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0-0.040 s
of (2.02 +/- 0.46)x10^-5 erg/cm2/s
(both in the 20 keV - 3 MeV energy range).
The time-integrated spectrum of the burst (from T0-1.2 to T0+4.5 s)
is well fitted (in the 10 keV - 3 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with
alpha = -0.55(-0.11, +0.12), and
Ep = 480(-54, +64) keV (chi2 = 120.1/119 dof).
The spectrum accumulated over the burst maximum (from T0-0.2 to T0+0.1
s) is well fitted (in the 10 keV - 3 MeV range)
by a power law with exponential cutoff model with
alpha = -0.28(-0.14, +0.15), and
Ep = 633(-71, +81) keV (chi2 = 44.0/56 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -3.06 (chi2 = 44.0/55 dof).
All the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.
The Konus-RF light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090929_T16384/KRF/
- GCN Circular #9976
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 090929A (Fermi-GBM trigger trigger 275891585:
Rau, GCN 9962) localized by Swift-BAT (Cummings and Krimm, GCN 9966)
triggered Konus-Wind at T0=16387.790 s UT (04:33:07.790).
As observed by Konus-Wind the burst
had a fluence of 1.32(-0.24, +0.23)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+0.736 s
of 2.04(-0.61, +0.60)x10^-5 erg/cm2/s
(both in the 20 keV - 3 MeV energy range).
The time-integrated spectrum of the burst (from T0 to T0+8.448 s)
is well fitted (in the 20 keV - 3 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with
alpha = -0.47(-0.22, +0.25), and
Ep = 574(-100, +151) keV (chi2 = 66.2/65 dof).
Fitting by GRB (Band) model yields:
the low-energy photon index alpha = -0.36(-0.29, +0.62),
the high energy photon index beta = -2.16(-1.41, +0.43),
the peak energy Ep = 494(-191, +175) keV (chi2 = 62.1/64 dof).
These values are consistent with the Konus-RF results (Golenetskii et
al., GCN 9968).
All the quoted errors are at the 90% confidence level.
The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090929_T16384/
- GCN Circular #9977
K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:
Swift performed a short Target of Opportunity observation of GRB 090929A
about 13 hours after the burst (Rau, GCN Circ. 9962; Cummings & Krimm, GCN
Circ. 9966; Golenetskii et al., GCN Circ. 9968). This area of sky was a
hot target for the XRT, so only a short observation was performed, with
1.4 ks of data being collected in Photon Counting mode.
We do not detect a source within the BAT error circle, to a 90% upper
limit of 0.015 count s^-1 over 0.3-10 keV. Assuming a typical counts to
flux conversion of 3.8 x 10^-11 erg cm^-2 ct^-1 (Evans et al., 2009,
MNRAS, 397, 1177), this corresponds to an observed flux of 5.7 x 10^-13
erg cm^-2 s^-1. We note that this is not a very constraining upper limit,
because of the greater than usual background caused by the high XRT CCD
temperature and the short exposure time.
Filtering out all photons below 1 keV, a more stringent upper limit of 9 x
10^-3 count s^-1 (1-10 keV; observed flux of ~3.4 x 10^-13 erg cm^-2 s^-1)
can be determined.
This circular is an official product of the Swift-XRT team.
- GCN Circular #9980
J. R. Cummings (GSFC/UMBC),
S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC),
E. E. Fenimore (LANL),
N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD),
K. Page (U Leicester),
D. M. Palmer (LANL),
A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
We report further analysis of Fermi-GBM GRB 090929A (Rau, et al.,
GCN Circ. 9962). The BAT ground-calculated position is the same
as stated in Cummings et al. (GCN Circ. 9966),
RA, Dec = 56.494, -5.952 or
RA (J2000) 03h 45m 57.9s
Dec (J2000) -05d 57' 50"
with an estimated 90% containment error radius of 3 arcmin. The
partial coding was 73-90% during the burst.
The mask-weighted lightcurve shows multiple peaks and spikes, at
T+1, T+2, T+4, T+5, and T+10 sec, where T0 is 04:33:07. T90 was
7 +- 2 seconds.
The time-averaged spectrum from T0 to T+12 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 0.96 +- 0.04. The fluence in the 15-150 keV band is
1.69 +- 0.07 x 10^-06 ergs/cm2. The 1-sec peak photon flux
measured from T+0.5 sec in the 15-150 keV band is
5.9 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90%
confidence level.
- GCN Circular #9981
M. H. Siegel (PSU) and K. L. Page (U. Leicester) report on behalf
of the Swift/UVOT team.
Swift/UVOT began settled observations of GRB 090929A about 13 hours
after
the burst (Rau, GCN Circ. 9962; Cummings & Krimm, GCN Circ. 9966;
Golenetskii et al., GCN Circ. 9968; Page, GCN Circ 9977). Due to the
presence of a 9th magnitude (V) star 45" from the center of the BAT
position,
data were only obtained in the UVM2 filter.
We do not detect any uncatalogued UV source within the BAT error circle.
The 3-sigma upper limit and summed exposure is reported below:
FILTER T_start(s) T_stop Exposure Mag/3UL
=============================================================
UVM2 47411 52924 2252 >21.26
=============================================================
This magnitude is not corrected for the Galactic extinction
corresponding
to a reddening of E_{B-V} = 0.07 (Schlegel et al., 1998, ApJS, 500,
525).
The photometry is on the UVOT photometric system described in Poole et
al.
(2008, MNRAS, 383, 627).
- GCN Circular #9992
N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji,
Y. Nishioka, K. Noda, M. Yamauchi (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The long GRB 090929A (Fermi-GBM trigger 275891585 / 090929190;
Arne Rau et al., GCN9962) triggered the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 04:33:04.634 UT (=T0).
The observed light curve shows a bright multi-peaked structure
starting at T0-1 s, ending at T0+5 s.
The total T90 duration is about 3.8 seconds.
The fluence in 100 - 1000 keV was 4.96 (-4.47, +5.32) x10-6 erg/cm2.
The 1-s peak flux measured from T0-0.5s was 5.59 (-0.68, +0.53)
photons/cm2/s in the same energy range.
The incident angle for this burst is not good, so the fluence
and peak flux might have large systematic uncertainties.
Preliminary result shows that the time-averaged spectrum from
T0-1s to T0+5s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 0.86(-0.80, +0.36), and
Epeak 557(-98, +117) keV (chi2/d.o.f. = 125/98).
All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.
The light curves for this burst is available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
- GCN Report 247.1
GCN_Report 247.1 has been posted:
http://gcn.gsfc.nasa.gov/reports/report_247_1.pdf
by K.L. Page
at U. Leicester
titled: "Swift Observations of GRB 090929A"
- GCN Circular #10010
S. K. Chakrabarti, A. Nandi, D. Debnath, T. C. Kotoch (ICSP, Kolkata, Ind=
ia),
A. R. Rao, J. P. Malkar, M. K. Hingar, V. K. Agrawal (TIFR, Mumbai, India=
),=20
T. R. Chidambaram, P. Vinod, S. Sreekumar (VSSC, Thiruvananthapuram, Indi=
a),
Y. D. Kotov, A. S. Buslov, V. N. Yurov, V. G. Tyshkevich, A. I. Arkhangel=
skij,
R. A.Zyatkov (MephI, Moscow, Russia) report:
The RT-2 Experiment onboard the CORONAS-PHOTON satellite has detected GRB
090929A (Fermi-GBM trigger 275891585/090929190; Rau, GCN 9962) which is
triggered at T0 =3D 04h 33m 04s (UT). The satellite was in the LIGHT mode
(pointing towards the SUN) with GOOD time (away from the polar and SAA
regions) observation of 1537 sec starting at 04h 21m 20sec (UT) and endin=
g at
04h 46m 57sec (UT).
The burst light curve (1 sec bin) shows double peak profile of total dura=
tion
of around 5 sec. The strongest peak count rate is ~ 310 cts/sec.
This burst is also independently detected by KONUS-RF, another instrument
onboard CORONAS-PHOTON satellite (Golenetskii et al., 2009, GCN 9968).
Both RT-2/S and RT-2/G detectors have registered the prompt emission from=
the
GRB090929A in the energy band of 60 =96 1000 with strongest emission in t=
he
energy band of 60 =96 215 keV.
=20
The light curve is available at the web-site:
http://csp.res.in/rt2_files/grb090929-lc.html
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