GRB 090217
GCN Circular 8902
Subject
GRB 090217: Fermi GBM detection
Date
2009-02-17T16:47:38Z (16 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 04:56:42.56 UT on 17 February 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090217 (trigger 256539404/ 090217206).
The on-ground calculated location, using the GBM trigger
data, is RA = 211.9, DEC = -2.8 (J2000 degrees,
equivalent to 14h 08m, -02d 48'), with an uncertainty
of 1.0 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 34 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve shows one major structured peak with a
duration (T90) of about 32.8 s (8-1000 keV) and (T50) of
about 4.6 s (8-1000 keV).
The time-averaged spectrum from T0+0.003 s to T0+19.584 s is
well fit by a power law function with an exponential
high energy cutoff. The power law index is -0.85 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 626 +/- 29 keV
(chi squared 631.30 for 482 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(3.08 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+6.272 s in the 8-1000 keV band
is 11.2 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well (chi squared 629.43 for
481d.o.f.) with Epeak= 610 +/- 32 keV, alpha = -0.845 +/- 0.023 and
beta = -2.86 +/- 0.36.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 8903
Subject
GRB090217: Fermi-LAT Detection
Date
2009-02-17T17:14:12Z (16 years ago)
From
Masanori Ohno at ISAS/JAXA <ohno@astro.isas.jaxa.jp>
Masanori Ohno(ISAS/JAXA), Julie McEnery(NASA/GSFC),
and Veronique Pelassa(CNRS/IN2P3/LPTA) report
on behalf of the Fermi LAT team:
We report a detection by the Fermi Large Area Telescope of emission
from a GRB at 04:56:51 UT with detection significance of more than 5 sigma.
This burst is spatially and temporally correlated with a GBM detected
burst (trigger 256539404, GCN 8902).
This burst was found in a blind search in the LAT data,
and also independently by follow up studies around the GBM location.
The emission continues for up to 20 seconds after the GBM trigger,
but commences several seconds after the GBM trigger.
The best LAT on-ground localization is found to be (RA,Dec=204.9, -8.4)
with a 90% containment radius of 0.52 deg (statistical; 68%
containment radius: 0.36 deg).
Further analysis is ongoing.
The Fermi LAT point of contact for this burst is
Masanori Ohno
(ohno@astro.isas.jaxa.jp)
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.
This message can be cited.
GCN Circular 8905
Subject
IPN localization of GRB 090217
Date
2009-02-18T19:55:40Z (16 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,
W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on
behalf of the GRS-Odyssey GRB team,
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,
K. Yamaoka, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada,
T. Murakami, K. Makishima, and Y. Hanabata on behalf of the Suzaku-WAM team,
A. von Kienlin, G. Lichti, and A. Rau, on behalf of the
INTEGRAL SPI-ACS and GRB team, and K. Hurley, on behalf of the INTEGRAL
SPI-ACS and Odyssey GRB teams, report:
Suzaku-WAM, Konus-Wind, INTEGRAL-SPI-ACS, and Mars Odyssey observed the
long GRB 090217 at about 04:56:42 UT (corresponding to the Fermi/GBM
trigger 256539404/ 090217206: von Kienlin, GCN 8902; also detected by
Fermi/LAT: Ohno et al., GCN 8903).
The burst light curve shows a multipeaked structure with a total
duration of ~40 sec.
Triangulation gives a MO-Konus annulus centered at RA(2000)=132.322 (08h
49m 17s) Dec(2000)=+18.838 (+18d 50' 18"), whose radius is 76.132 +/-
0.104 deg (3 sigma), and a Konus-WAM annulus centered at
RA(2000)=135.708 (09h 02m 50s) Dec(2000)=+21.300 (+21d 17' 59"), whose
radius is 73.641 � 0.941 deg (3sigma). These annuli intersect at grazing
incidence to form two long error boxes, one of which may be eliminated
by the Konus ecliptic latitude response.
The resulting error box has the coordinates:
-----------------------------------------------------
RA(2000), deg Dec(2000), deg
-----------------------------------------------------
Center:
204.865 (13h 39m 28s) -7.442 (-07d 26' 31")
Corners:
212.234 (14h 08m 56s) +13.782 (+13d 46' 57")
199.337 (13h 17m 21s) -19.856 (-19d 51' 21")
197.625 (13h 10m 30s) -22.539 (-22d 32' 21")
210.398 (14h 01m 36s) + 8.568 (+08d 34' 06")
-----------------------------------------------------
The error box area is 7.2 sq. deg.
This box may be improved.
The box is consistent with the LAT location (Ohno et al., GCN 8903).
The center line of the MO-Konus annulus passes 0.385 degrees from the
center of the Fermi/LAT error circle, and the annulus intersects the
90% containment error circle at:
-----------------------------------------------------
RA(2000), deg Dec(2000), deg
-----------------------------------------------------
204.800 (13h 39m 12s) -7.890 (-07d 53' 22")
204.505 (13h 38m 01s) -8.057 (-08d 03' 24")
204.471 (13h 37m 53s) -8.701 (-08d 42' 04")
204.375 (13h 37m 30s) -8.379 (-08d 22' 45")
----------------------------------------------------
The K-W light curve of this GRB and IPN triangulation map is
available at http://www.ioffe.ru/LEA/GRBs/GRB090217_T17804/
GCN Circular 8906
Subject
Konus-Wind observation of GRB 090217
Date
2009-02-18T20:01:46Z (16 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
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 long GRB 090217 (Fermi/GBM trigger 256539404/ 090217206: von
Kienlin, GCN 8902) localized by Fermi/LAT (Ohno et al., GCN 8903) and
IPN (Mitrofanov et al., GCN 8905)
triggered Konus-Wind at T0=17804.799 s UT (04:56:44.799) .
As observed by Konus-Wind the burst
had a fluence of 3.13(-0.30, +0.35)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+4.592 s
of 4.72(-0.81, +0.86)x10^-6 erg/cm2/s
(both in the 20 keV - 4 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+24.832 s) is well fitted (in the 20 keV - 4 MeV
range) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.87(-0.14, +0.15),
and Ep = 534(-78, +105) keV (chi2 = 71.5/73 dof).
Fitting by GRB (Band) model yields:
the low-energy photon index alpha = -0.80(-0.16, +0.18),
the high energy photon index beta < -2.19,
the peak energy Ep = 480(-82, +120) keV (chi2 = 70.0/72 dof).
All the quoted errors are at the 90% confidence level.
GCN Circular 8907
Subject
GRB090217: XRT analysis
Date
2009-02-18T21:38:10Z (16 years ago)
From
Olivier Godet at U.of Leicester <og19@star.le.ac.uk>
O. Godet (U. Leicester) on behalf the Swift-XRT team
The Swift-XRT started observing the field of GRB090217 (GCN Circ. 8903) 39ks
after the LAT trigger (T0) using an early LAT position (RA,Dec (J2000) =
204.436 deg, -8.858 deg and a 90% confidence error radius of 0.454 deg) which
is 39 arcmin away from that quoted in Ohno et al. (GCN Circ. 8903).
We analysed 7.5ks of Photon Counting (PC) data collected from T0+39ks to
T0+62.8ks. The LAT error circle is larger than the XRT field of view. Three
X-ray sources with a signal-to-noise ratio larger than 3 were found at
(J2000):
S1: RA, Dec, err = 13 37 18.11, -08 45 28.5, 5.5 arcsec
S2: RA, Dec, err = 13 37 40.35 -09 01 29.7, 4.5 arcsec
S3: RA, Dec, err = 13 37 39.49 -09 02 26.6, 4.4 arcsec
The XRT error radii are quoted at 90% confidence level.
The position S3 is consistent with the AGN HE 1335-0847 previously detected by
ROSAT. The position S2 is consistent with that of a star from the USNO-B1
catalog, while the position S1 is 6.7 arcsec away from a USNO-B1 source.
The data for S1 and S2 are too sparse to check for any variability during the
observation. Nevertheless, none of these sources are likely to be the X-ray
afterglow of GRB 090217.
This is an official product of the Swift-XRT team.
GCN Circular 8908
Subject
GRB 090217: Suzaku WAM observation of the prompt emission
Date
2009-02-19T04:55:52Z (16 years ago)
From
Yoshitaka Hanabata at Hiroshima U <hanabata@hep01.hepl.hiroshima-u.ac.jp>
Y. Hanabata, Y. Fukazawa, T. Takahashi, T. Uehara, C. Kira (HiroshimaU.),
Y. Terada, M. Tashiro, Y. Urata, A. Endo, K. Onda, N. Kodaka,
K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), M. Ohno,
M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), K. Yamaoka,
S. Sugita (Aoyama Gakuin U.), T. Enoto, K. Nakazawa, K. Makishima
(Univ. of Tokyo), Y.E. Nakagawa, T. Tamagawa (RIKEN),
E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono,
H. Hayashi (Univ. of Miyazaki), S. Hong (Nihon U.),
N. Vasquez (Tokyo Tech), on behalf of the Suzaku WAM team, report:
The bright, long Fermi-LAT detected GRB 090217 (Fermi-GBM
trigger #256539404 ; von Kielin et al., GCN 8902;
Fermi-LAT detection ; Ohno et al., ; GCN 8903)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 04:56:42.98 UT (=T0).
The observed light curve shows a multi-peaked structure
starting at T0-3s, ending at T0+19s with a duration
(T90) of about 14 seconds. The fluence in 100 - 1000 keV
was 1.56(+0.05,-0.09)x10^-5 erg/cm^2. The 1-s peak flux measured
from T0+7s was 3.0 (+0.2,-0.3) photons/cm^2/s in the same energy range.
Preliminary result shows that the time-averaged spectrum from
T0-3s to T0+20s is well fitted by a power-law with exponential cutoff model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 0.81(+0.26,-0.31), and
Epeak 780(+187,-126) keV (chi^2/d.o.f. = 41.0/24).
The GRB Band model also gives a good fit with only
an upper limit on the high-energy photon index as follows:
the low-energy photon index alpha: -0.75(+0.50,-0.28),
the high-energy photon index beta: < -2.33,
and the peak energy Epeak: 748(+195,-175) keV (chi^2/d.o.f = 40.4/23).
Please note that this GRB comes from the WAM 2 on-axis direction, which
has a large uncertaintiy only in absolute flux.
All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.
The light curves for this burst will be available soon at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html