Swift/BAT detected the first burst from 1E 1841-045 in May 2010 with intermittent burst activity recorded through at least July 2011. Here we present Swift and Fermi/GBM observations of this burst ...activity and search for correlated changes to the persistent X-ray emission of the source. The T90 durations of the bursts range between 18-140 ms, comparable to other magnetar burst durations, while the energy released in each burst ranges between (0.8 - 25)E38 erg, which is in the low side of SGR bursts. We find that the bursting activity did not have a significant effect on the persistent flux level of the source. We argue that the mechanism leading to this sporadic burst activity in 1E 1841-045 might not involve large scale restructuring (either crustal or magnetospheric) as seen in other magnetar sources.
SWift/BAT detected the first burst from 1E 1841-045 in May 2010 with intermittent burst activity recorded through at least July 2011. Here we present Swift and Fermi/GBM observations of this burst ...activity and search for correlated changes to the persistent X-ray emission of the source. The T90 durations of the bursts range between 18 - 140 ms, comparable to other magnetar burst durations, while the energy released in each burst ranges between (0.8-25) x 1038 erg, which is in the low side of SGR bursts. We find that the bursting activity did not have a significant effect on the persistent flux level of the source. We argue that the mechanism leading to this sporadic burst activity in IE 1841-045 might not involve large scale restructuring (either crustal or magnetospheric) as seen in other magnetar sources.
Astrophys.J.651:985-993,2006 We report the simultaneous observations of the prompt emission in the
gamma-ray and hard X-ray bands by the Swift-BAT and the KONUS-Wind instruments
of the short-hard ...burst, GRB 060313. The observations reveal multiple peaks in
both the gamma-ray and hard X-ray bands suggesting a highly variable outflow
from the central explosion. We also describe the early-time observations of the
X-ray and UV/Optical afterglows by the Swift XRT and UVOT instruments. The
combination of the X-ray and UV/Optical observations provide the most
comprehensive lightcurves to date of a short-hard burst at such an early epoch.
The afterglows exhibit complex structure with different decay indices and
flaring. This behavior can be explained by the combination of a structured jet,
radiative loss of energy, and decreasing microphysics parameters occurring in a
circum-burst medium with densities varying by a factor of approximately two on
a length scale of 10^17 cm. These density variations are normally associated
with the environment of a massive star and inhomogeneities in its windy medium.
However, the mean density of the observed medium (n approximately 10^−4
cm^3) is much less than that expected for a massive star. Although the collapse
of a massive star as the origin of GRB 060313 is unlikely, the merger of a
compact binary also poses problems for explaining the behavior of this burst.
Two possible suggestions for explaining this scenario are: some short bursts
may arise from a mechanism that does not invoke the conventional compact binary
model, or soft late-time central engine activity is producing UV/optical but no
X-ray flaring.
Astrophys.J. 645 (2006) 1315-1322 The unique capability of the Swift satellite to perform a prompt and
autonomous slew to a newly detected Gamma-Ray Burst (GRB) has yielded the
discovery of ...interesting new properties of GRB X-ray afterglows, such as the
steep early lightcurve decay and the frequent presence of flares detected up to
a few hours after the GRB trigger. We present observations of GRB 050607, the
fourth case of a GRB discovered by Swift with flares superimposed on the
overall fading X-ray afterglow. The flares of GRB 050607 were not symmetric as
in previously reported cases, showing a very steep rise and a shallower decay,
similar to the Fast Rise, Exponential Decay that are frequently observed in the
gamma-ray prompt emission. The brighter flare had a flux increase by a factor
of approximately 25,peaking for 30 seconds at a count rate of approximately 30
counts s-1, and it presented hints of addition short time scale activity during
the decay phase. There is evidence of spectral evolution during the flares. In
particular, at the onset of the flares the observed emission was harder, with a
gradual softening as each flare decayed. The very short time scale and the
spectral variability during the flaring activity are indicators of possible
extended periods of energy emission by the GRB central engine. The flares were
followed by a phase of shallow decay, during which the forward shock was being
refreshed by a long-lived central engine or by shells of lower Lorentz factors,
and by a steepening after approximately 12 ks to a decay slope considered
typical of X-ray afterglows.
RXTE observations of GRB afterglows Marshall, Francis E.; Swank, Jean; Valinia, Azita ...
Nuclear physics. Section B, Proceedings supplement,
1999, 1999-1-00, Volume:
69, Issue:
1
Journal Article
Variable X-ray sources that appear to be the afterglows of the strong gamma-ray bursts GRB 970616 and GRB 970828 have been discovered with the RXTE PCA. First seen less than 4 hours after the burst, ...the flux from the sources decreased with time. Although near the sensitivity limit of the PCA, the sources are the brightest afterglows yet seen in X-rays. Similar observations of two other bursts did not detect any afterglows. These results are part of a continuing collaboration between RXTE, BATSE, and IPN scientists to rapidly detect X-ray afterglows of bright gamma-ray bursts.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We report the simultaneous observations of the prompt emission in the gamma-ray and hard X-ray bands by the Swift-BAT and the KONUS-Wind instruments of the short-hard burst, GRB 060313. The ...observations reveal multiple peaks in both the gamma-ray and hard X-ray bands suggesting a highly variable outflow from the central explosion. We also describe the early-time observations of the X-ray and UV/Optical afterglows by the Swift XRT and UVOT instruments. The combination of the X-ray and UV/Optical observations provide the most comprehensive lightcurves to date of a short-hard burst at such an early epoch. The afterglows exhibit complex structure with different decay indices and flaring. This behavior can be explained by the combination of a structured jet, radiative loss of energy, and decreasing microphysics parameters occurring in a circum-burst medium with densities varying by a factor of approximately two on a length scale of 10^17 cm. These density variations are normally associated with the environment of a massive star and inhomogeneities in its windy medium. However, the mean density of the observed medium (n approximately 10^−4 cm^3) is much less than that expected for a massive star. Although the collapse of a massive star as the origin of GRB 060313 is unlikely, the merger of a compact binary also poses problems for explaining the behavior of this burst. Two possible suggestions for explaining this scenario are: some short bursts may arise from a mechanism that does not invoke the conventional compact binary model, or soft late-time central engine activity is producing UV/optical but no X-ray flaring.
The unique capability of the Swift satellite to perform a prompt and autonomous slew to a newly detected Gamma-Ray Burst (GRB) has yielded the discovery of interesting new properties of GRB X-ray ...afterglows, such as the steep early lightcurve decay and the frequent presence of flares detected up to a few hours after the GRB trigger. We present observations of GRB 050607, the fourth case of a GRB discovered by Swift with flares superimposed on the overall fading X-ray afterglow. The flares of GRB 050607 were not symmetric as in previously reported cases, showing a very steep rise and a shallower decay, similar to the Fast Rise, Exponential Decay that are frequently observed in the gamma-ray prompt emission. The brighter flare had a flux increase by a factor of approximately 25,peaking for 30 seconds at a count rate of approximately 30 counts s-1, and it presented hints of addition short time scale activity during the decay phase. There is evidence of spectral evolution during the flares. In particular, at the onset of the flares the observed emission was harder, with a gradual softening as each flare decayed. The very short time scale and the spectral variability during the flaring activity are indicators of possible extended periods of energy emission by the GRB central engine. The flares were followed by a phase of shallow decay, during which the forward shock was being refreshed by a long-lived central engine or by shells of lower Lorentz factors, and by a steepening after approximately 12 ks to a decay slope considered typical of X-ray afterglows.
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