GRB 120316A
GCN Circular 13070
Subject
GBM trigger 353549464 (GRB 120316A?) : High-energy photon emission in Fermi/LAT data
Date
2012-03-19T23:56:20Z (13 years ago)
From
Weikang Zheng at U.of Michigan <zwk@umich.edu>
Weikang Zheng and Carl Akerlof report on behalf of the ROTSE collaboration:
High-energy photon emission in Fermi/LAT data was found to be correlated
with GBM trigger 353549464 (00:11:02 UT on Mar. 16, 2012, probably GRB
120316A) as a follow-up of a routine search in GBM trigger catalogs using
our LAT data processing pipeline. The GBM trigger location (RA = 47.93,
Dec = -63.09) was about 17 degree from the LAT boresight, and the zenith
angle was about 54 degrees. A maximum likelihood analysis gives a TS value
of 32.9 over a time window extending to 160s after the trigger. In that time
span, more than 10 photons above 100 MeV were detected, with the highest
energy of ~1.98 GeV at 27s after the burst. The GRB location estimated by
the likelihood analysis is RA = 57.70, Dec = -56.51 with uncertainty ~0.5
degree. This is ~8 degrees away from the GBM trigger location. Our location
is consistent with the preliminary IPN error box (GCN in preparation, Hurley
& Pal'shin)
The photon information can be found in the following link, including the
skymap
and light curve figures:
http://www.rotse.net/LAT/GBMTriggers/353549464/353549464_res.html
GCN Circular 13073
Subject
IPN Triangulation of GRB 120316A
Date
2012-03-20T14:09:19Z (13 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
K. Hurley on behalf of the Mars Odyssey and MESSENGER GRB teams,
I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,
S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi
GBM team,
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on
behalf of the Swift-BAT team, and
K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro,
Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM
team, report:
The long GRB 120316A was observed by Fermi (GBM: trigger 353549464),
INTEGRAL (SPI-ACS), Konus-Wind, Mars Odyssey (HEND), Suzaku (WAM), and
Swift (BAT) (outside the coded field of view) at about 662 s UT (00:11:02).
We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
57.016 (03h 48m 04s) -56.288 (-56d 17' 15")
Corners:
56.269 (03h 45m 05s) -57.541 (-57d 32' 28")
57.363 (03h 49m 27s) -57.038 (-57d 02' 16")
57.698 (03h 50m 48s) -55.028 (-55d 01' 42")
56.676 (03h 46m 42s) -55.538 (-55d 32' 18")
---------------------------------------------
The error box area is 1.07 sq. deg, and its maximum
dimension is 2.6 deg.
This box can be improved.
The LAT position reported by Zheng & Akerlof (GCN
13070 ) is consistent with the IPN box (the center of this position is
outside the box, but the error circle overlaps with the box).
The time history and spectrum will be given in a forthcoming GCN Circular.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB120316_T00672/IPN/
GCN Circular 13074
Subject
Konus-Wind observation of GRB 120316A
Date
2012-03-20T14:18:02Z (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 GRB 120316A (GBM trigger 353549464;
Fermi/LAT detection: Zheng & Akerlof, GCN 13070;
IPN localization: Hurley at al., GCN 13073)
triggered Konus-Wind at T0=00672.966s UT (00:11:12.966)
The light curve shows multiple partly overlapped pulses.
A total duration of the burst is ~32 s.
The emission is seen up to ~8 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB120316_T00672/
As observed by Konus-Wind the burst
had a fluence of 2.3(-0.4,+0.5)x10-5 erg/cm2,
and a 256-ms peak flux, measured from T0+9.216 s,
of 2.5(-0.5,+0.7)x10-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst
(measured from T0 to T0+15.872 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model, for which
alpha = -0.92 (-0.13, +0.15),
and Ep = 539(-109, +167) keV,
chi2 = 92/86 dof.
All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.
GCN Circular 13085
Subject
GRB 120316A: Fermi-GBM and Fermi-LAT Observations
Date
2012-03-21T21:22:59Z (13 years ago)
From
Giacomo Vianello at SLAC <giacomov@slac.stanford.edu>
Giacomo Vianello (CIFS/SLAC), Nicola Omodei (Stanford U.), J. L.
Racusin (NASA/GSFC), P. Jenke (MSFC/NPP) report on behalf of the Fermi
GBM and LAT Teams:
At 00:11:02.56 UT on 16 March 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 120316A (trigger 353549464 / 120316008),
which was also detected by Konus-Wind (GCN 13074) and triangulated by
the IPN (GCN 13073). The GBM H.I.T.L. location is found to be RA, Dec
(J2000) = 48.5, -64.3 with a error radius (90% containment,
statistical) of 1.2 degrees.
The GBM light curve shows multiple peaks with a duration of T90 = 27.5
+/- 0.4 seconds, and a signal extending to 500 keV in the NaI's and
850 keV in the BGO's.
The GRB is barely detected by the LAT, with a Test Statistic slightly
below the TS=25 threshold usually adopted for issuing circulars. The
best LAT on-ground location is found to be RA,Dec (J2000) = 57.97,
-56.46 with an error radius of 0.65 deg (90% containment, statistical
error only). This was 9.7 deg from the LAT boresight at the time of
the trigger.
The LAT position is compatible with that found by Zheng et al. (GCN
13070) and by Hurley et al. (GCN 13073), and is ~9 deg away from the
best GBM localization. Modeling of the uncertainties in GBM
localizations, using known reference locations, suggests that whilst
the majority (>90%) are well-represented by a ~3 deg systematic error,
GRB120316A appears to belong to a small tail which has a much larger
systematic uncertainty, centered on ~10 deg (see Connaughton et al.,
in preparation).
The spectrum of this GRB from 10 keV to 300 GeV, integrated over the
time interval 0-32 s from the trigger time, is well described by a
Band function with Epeak = 552 -25 +22 keV, alpha = -0.77 +/- 0.02,
beta = -2.90 +/-0.15. The fluence in the 10 keV - 1 MeV energy range
is 2.57 ( +/- 0.03 (stat) +/- 0.2 (sys) ) x 10^-5 erg/cm2, compatible
with the value found by Golenetskii et al (GCN 13074).
The spectral analysis results presented above are preliminary;
The Fermi LAT point of contact for this burst is Giacomo Vianello
(giacomov@slac.stanford.edu). The GBM point of contact is Peter Jenke
(peter.a.jenke@nasa.gov).
The Fermi LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product of
an international
collaboration between NASA and DOE in the U.S. and many scientific
institutions across France, Italy, Japan and Sweden.
GCN Circular 13088
Subject
GRB 120316A : Suzaku WAM observation of the prompt emission
Date
2012-03-23T07:51:49Z (13 years ago)
From
Yoshitaka Hanabata at Hiroshima U <hanabata@hep01.hepl.hiroshima-u.ac.jp>
Y. Hanabata, T. Uehara, T. Kawano, K. Takaki, M. Mizuno, M. Ohno,
Y. Fukazawa (Hiroshima U.), W. Iwakiri, M. Tashiro, Y. Terada,
T. Yasuda, K. Takahara, M. Asahina, S. Kobayashi, A. Sakamoto (Saitama U.),
S. Sugita (Nagoya U.), K. Yamaoka (Aoyama Gakuin U.), M. Kokubun,
T. Takahashi (ISAS/JAXA), Y. E. Nakagawa (Waseda U.), N. Ohmori, M. Akiyama,
M. Yamauchi (Univ. of Miyazaki), C-J. Chuang, Y. Urata, P. Tsai (NCU),
K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:
The long GRB 120316A (GBM trigger 353549464; Fermi-LAT detection:
Zheng & Akerlof, GCN 13070; IPN localization: Hurley at al., GCN 13073)
was detected by the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 00:11:02 UT (=T0).
The observed light curve shows a multi-peaked structure starting at T0,
ending at T0+28 s with a duration (T90) of about 24 seconds. The
fluence in 100 - 1000 keV was 1.79 (-0.49, +0.07) x 10^-5 erg/cm^2. The
1-s peak flux measured from T0+21 s was 2.75 (-1.02, +0.31)
photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from
T0 to T0+28 s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -0.44 (-0.61, +0.89),
the high-energy photon index beta: -2.63 (-0.58, +0.31),
and the peak energy Epeak: 530 (-76, +89) keV (chi^2/d.o.f = 12.6/12).
Due to the brightness of this burst, a 3% systematic error was added
for low energy channels. All the quoted errors are at statistical 90%
confidence level.
The light curves for this burst will be available at:
http://www.astro.isas.ac.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html