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G. Ricker,
K. Hurley, D. Lamb,
S. Woosley,
J.-L. Atteia,
N. Kawai,
R. Vanderspek,
G. Crew,
J. Doty,
J. Villasenor, [......],
T. Cline,
J. G. Jernigan,
A. Levine,
F. Martel,
E. Morgan,
J. Braga,
R. Manchanda,
G. Pizzichini,
K. Takagishi,
and M. Yamauchi
[show abstract]
[hide abstract]
ABSTRACT: On 2001 September 21 at 05:15:50.56 UT, the French Gamma Telescope (FREGATE) on the High Energy Transient Explorer (HETE) detected a bright gamma-ray burst (GRB). The burst was also seen by the X-detector on the Wide-field X-ray Monitor (WXM) instrument and was therefore well localized in the X-direction; however, the burst was outside the fully coded field of view of the WXM Y-detector, and therefore information on the Y-direction of the burst was limited. Cross-correlation of the HETE and Ulysses time histories yielded an Interplanetary Network (IPN) annulus that crosses the HETE error strip at an ~45° angle. The intersection of the HETE error strip and the IPN annulus produces a diamond-shaped error region for the location of the burst having an area of 310 arcmin2. Based on the FREGATE and WXM light curves, the duration of the burst is characterized by t90 = 34.2 s in the WXM 4-25 keV energy range, and 23.8 and 21.8 s in the FREGATE 6-40 and 32-400 keV energy ranges, respectively. The fluence of the burst in these same energy ranges is 4.8 × 10-6, 5.5 × 10-6, and 11.4 × 10-6 ergs cm-2, respectively. Subsequent optical and radio observations by ground-based observers have identified the afterglow of GRB 010921 and determined an apparent redshift of z = 0.450.
The Astrophysical Journal 12/2008; 571(2):L127. · 6.02 Impact Factor
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Takanori Sakamoto,
G. Sato,
L. Barbier,
S. Barthelmy,
J. Cummings,
E. Fenimore,
N. Gehrels,
D. Hullinger,
H. Krimm,
C. Markwardt,
D. Palmer,
A. Parsons,
J. Tueller, D. Lamb
[show abstract]
[hide abstract]
ABSTRACT: We report a correlation based on the spectral simulation study in the
prompt emission spectrum of gamma-ray bursts (GRBs). The correlation is
between the photon index derived from a simple
power-law model by the Swift Burst Alert Telescope (BAT) and the Epeak
energy, which is the peak energy in the nuF_nu spectrum. We take into
account not only the various range of Epeak energies and fluences, but
also distributions for both the low-energy photon index and the
high-energy photon index in the smoothly broken power-law model. Our
correlation is consistent with the photon index observed by BAT and
Epeak measured by BAT and other GRB instruments. Since about 80% of GRBs
observed by BAT are acceptably fit with the simple power-law model
because of the relatively narrow energy range of BAT, this relationship
can be used to estimate Epeak for most of the Swift GRBs.
08/2006; 38:380.
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T Sakamoto,
L. Barbier,
S. Barthelmy,
J. Cummings,
E. Fenimore,
N. Gehrels,
D. Hullinger,
H. Krimm,
C. Markwardt,
D Palmer, [......],
J. Tueller,
R. Aptekar,
T. Cline,
S. Golenetskii,
E. Mazets,
V. Pal'shin,
G. Ricker, D. Lamb,
J. -L. Atteia,
N Kawai
[show abstract]
[hide abstract]
ABSTRACT: Thanks to the rapid position notice and response by HETE-2 and Swift, the X-ray afterglow emissions have been found for four recent short gamma-ray bursts (GRBs; GRB 050509b, GRB 050709, GRB 050724, and GRB 050813). The positions of three out of four short GRBs are coincident with galaxies with no current or recent star formation. This discovery tightens the case for a different origin for short and long GRBs. On the other hand, from the prompt emission point of view, a short GRB shows a harder spectrum comparing to that of the long duration GRBs according to the BATSE observations. We investigate the prompt emission properties of four short GRBs observed by Swift/BAT. We found that the hardness of all four BAT short GRBs is in between the BATSE range for short and long GRBs. We will discuss the spectral properties of short GRBs including the short GRB sample of Konus-Wind and HETE-2 to understand the hard nature of the BATSE short GRBs.
06/2006;
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Y. Shirasaki,
N. Kawai,
A. Yoshida,
M. Matsuoka,
T. Tamagawa,
K. Torii,
T. Sakamoto,
M. Suzuki,
Y. Urata,
R. Sato,
Y. Nakagawa,
D. Takahashi,
E. Fenimore,
M. Galassi, D. Lamb,
C. Graziani,
T. Donaghy,
R. Vanderspek
[show abstract]
[hide abstract]
ABSTRACT: The Wide field X-ray Monitor (WXM) of HETE-2 was designed to localize a
Gamma Ray Burst occurred in its wide field of view (80° ×
80°) with 10' accuracy.
In-orbit calibration is performed by observing Crab Nebula and Sco X-1,
then the alignment between the WXM and optical camera system is tuned.
Also the detection efficiency and the energy response obtained from the
ground experiment are checked.
Performance of the on-board localization and burst alert system are
examined from X-ray burst observations.
05/2004; 312:543.
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N. Butler,
A. Dullighan,
G. Ricker,
G. Monnelly,
R. Vanderspek,
P. Ford,
S. Burles,
K. Hurley, D. Lamb,
A. Fruchter,
R. Wainscott,
H. Ebeling,
G. Luppino,
N. Kawai,
A. Yoshida
[show abstract]
[hide abstract]
ABSTRACT: We failed to detect a counterpart source to the short/hard GRB 020531,
which was discovered by the HETE satellite. We present observations in
the X-rays made with Chandra in 2 epochs. We also summarize observations
made in the optical with the Subaru telescope, with Magellan, and with 2
orbits of Hubble STIS. The X-ray afterglow flux must have been fainter
than 2× 10-15 erg cm-2 s-1 5.27
days after the GRB. The source must have faded faster than
t-2.1 in the optical.
05/2004; 312:201.
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[show abstract]
[hide abstract]
ABSTRACT: We review the significance determination for emission lines in the Chandra HETGS spectrum for GRB020813, and we report on a search for additional lines in high resolution Chandra spectra. No previously unclaimed features are found. We also discuss the significance of lines sets reportedly discovered using XMM data for GRB011211 and GRB030227. We find that these features are likely of modest, though not negligible, significance. Comment: 4 pages, 1 figures, to appear in Santa Fe GRB Conference Proceedings, 2003
01/2004;
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[show abstract]
[hide abstract]
ABSTRACT: The X-ray-rich GRB030528 was detected by the HETE satellite and its localization was rapidly disseminated. However, early optical observations failed to detect a counterpart source. In a 2-epoch ToO observation with Chandra, we discovered a fading X-ray source likely counterpart to GRB030528. The source brightness was typical of X-ray afterglows observed at similar epochs. Other observers detected an IR source at a location consistent with the X-ray source. The X-ray spectrum is not consistent with a large absorbing column. Comment: 4 pages, 1 figures, to appear in Santa Fe GRB Conference Proceedings, 2003
01/2004;
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[show abstract]
[hide abstract]
ABSTRACT: The X-ray-flash XRF030723 was detected by the HETE satellite and rapidly disseminated, allowing for an optical transient to be detected ~1 day after the burst. We discuss observations in the optical with Magellan, which confirmed the fade of the optical transient. In a 2-epoch ToO observation with Chandra, we discovered a fading X-ray source spatially coincident with the optical transient. We present spectral fits to the X-ray data. We also discuss the possibility that the source underwent a rebrightening in the X-rays, as was observed in the optical. We find that the significance of a possible rebrightening is very low (~1 sigma). Comment: 4 pages, 2 figures, to appear in Santa Fe GRB Conference Proceedings, 2003
01/2004;
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G. Ricker,
K. Hurley, D. Lamb,
S. Woosley,
J. -L. Atteia,
N Kawai,
R. Vanderspek,
G. Crew,
J. Doty,
J. Villasenor, [......],
T. Cline,
J. G. Jernigan,
A Levine,
F. Martel,
E. Morgan,
J. Braga,
R. Manchanda,
G. Pizzichini,
K Takagishi,
M Yamauchi
[show abstract]
[hide abstract]
ABSTRACT: On September 21 at 18950.56 SOD (05:15:50.56) UT the FREGATE gamma-ray instrument on the High Energy Transient Explorer (HETE) detected a bright gamma-ray burst (GRB). The burst was also seen by the X-detector on the WXM X-ray instrument and was therefore well-localized in the X direction; however, the burst was outside the fully-coded field-of-view of the WXM Y-detector, and therefore information on the Y direction of the burst was limited. Cross-correlation of the HETE and Ulysses time histories yielded an Interplanetary Network (IPN) annulus that crosses the HETE error strip at a ~45 degree angle. The intersection of the HETE error strip and the IPN annulus produces a diamond-shaped error region for the location of the burst having an area of 310 square arcminutes. Based on the FREGATE and WXM light curves, the duration of the burst is characterized by a t90 = 18.4 s in the WXM 4 - 25 keV energy range, and 23.8 s and 21.8 s in the FREGATE 6 - 40 and 32 - 400 keV energy ranges, respectively. The fluence of the burst in these same energy ranges is 4.8 10^{-6}, 5.5 10^{-6}, and 11.4 10^{-6} erg cm^{-2}, respectively. Subsequent optical and radio observations by ground-based observers have identified the afterglow of GRB010921 and determined an apparent redshift of z = 0.450.
02/2002;
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A. Achterberg,
M. Ackermann,
J Adams,
J. Ahrens,
K. Andeen,
J. Auffenberg,
J N Bahcall,
X Bai,
B. Baret,
S. W. Barwick, [......],
T. Cline,
G. Crew,
M. Feroci,
F. Frontera,
K. Hurley, D. Lamb,
A. Rau,
F. Rossi,
G. Ricker,
A. von Kienlin
Astrophysical Journal, v.674, 357-370 (2008).
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[show abstract]
[hide abstract]
ABSTRACT: Gamma-ray bursts GRBs are the most brilliant events in the universe The
intrinsic luminosities of the bursts span more than five decades At
first glance therefore these events would hardly seem to be a promising
means of constraining the properties of dark energy However very
recently a relation between the peak energy of the burst spectrum the
isotropic-equivalent energy of the burst and the time of the jet break
in the optical afterglow of the burst -- all in the rest frame of the
burst source --have been found for long GRBs In a way that is exactly
analogous to the way in which the relation between the peak luminosity
and the rate of decline of the light curve of Type Ia supernovae can be
used to make Type Ia supernovae excellent standard candles for cosmology
so too the relation recently found for GRBs holds great promise for
making these brilliant events standard candles Still more recently it
has been pointed out that if short GRBs are due to the merger of NS-NS
or NS-BH binaries -- for which there is now compelling evidence
following the localizations in the past year of several short GRBs by
HETE-2 and Swift -- and if they are detected in gamma-rays and by
gravitational wave experiments they can be used as standard sirens to
constrain the properties of dark energy We discuss the promise of these
two approaches and their current status We then describe in detail a
concept for a MIDEX-class mission that would be able to detect 2000 GRBs
in two years and would use the resulting large samples of short and long
bursts to constrain
36:3175.
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Y. Nakagawa,
G. Ricker,
J.-L. Atteia,
N. Kawai, D. Lamb,
S. Woosley,
T. Donaghy,
E. Fenimore,
M. Galassi,
C. Graziani, [......],
J. G. Jernigan,
A. Levine,
G. Azzibrouck,
J. Braga,
R. Manchanda,
G. Pizzichini,
M. Boer,
J.-F. Olive,
J.-P. Dezalay,
K. Hurley
GRB Coordinates Network. 3053:1.
