scholarly journals GRB 060714: No Clear Dividing Line between Prompt Emission and X‐Ray Flares

2007 ◽  
Vol 665 (1) ◽  
pp. 554-568 ◽  
Author(s):  
H. A. Krimm ◽  
J. Granot ◽  
F. E. Marshall ◽  
M. Perri ◽  
S. D. Barthelmy ◽  
...  
Keyword(s):  
X Ray ◽  
Prompt Emission ◽  
Dividing Line

scholarly journals Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars

2020 ◽  
Vol 499 (4) ◽  
pp. 5986-5992
Author(s):  
Nikhil Sarin ◽  
Paul D Lasky ◽  
Gregory Ashton
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Dipole Radiation ◽  
X Ray ◽  
Radiative Efficiency ◽  
Central Engine ◽  
Radiative Losses ◽  
Wave Emission ◽  
Prompt Emission

ABSTRACT The spin-down energy of millisecond magnetars has been invoked to explain X-ray afterglow observations of a significant fraction of short and long gamma-ray bursts. Here, we extend models previously introduced in the literature, incorporating radiative losses with the spin-down of a magnetar central engine through an arbitrary braking index. Combining this with a model for the tail of the prompt emission, we show that our model can better explain the data than millisecond-magnetar models without radiative losses or those that invoke spin-down solely through vacuum dipole radiation. We find that our model predicts a subset of X-ray flares seen in some gamma-ray bursts. We can further explain the diversity of X-ray plateaus by altering the radiative efficiency and measure the braking index of newly born millisecond magnetars. We measure the braking index of GRB061121 as $n=4.85^{+0.11}_{-0.15}$ suggesting the millisecond-magnetar born in this gamma-ray burst spins down predominantly through gravitational-wave emission.

The Prompt Emission of GRB 990712 with [ITAL]B[/ITAL][CSC][ITAL]eppo[/ITAL][/CSC][ITAL]SAX[/ITAL]: Evidence of a Transient X-Ray Emission Feature

2001 ◽  
Vol 550 (1) ◽  
pp. L47-L51 ◽  
Author(s):  
F. Frontera ◽  
L. Amati ◽  
M. Vietri ◽  
J. J. M. in ’t Zand ◽  
E. Costa ◽  
...  
Keyword(s):  
Emission Feature ◽  
X Ray ◽  
Prompt Emission

THE INTERPLAY OF PROMPT AND AFTERGLOW EMISSION IN GRB 060418

2008 ◽  
Vol 17 (09) ◽  
pp. 1343-1349 ◽  
Author(s):  
S. D. VERGANI ◽  
D. MALESANI ◽  
E. MOLINARI
Keyword(s):  
Gamma Rays ◽  
Spectral Properties ◽  
Gamma Ray ◽  
Early Time ◽  
Lorentz Factor ◽  
X Ray ◽  
Central Engine ◽  
Low Energies ◽  
Prompt Emission

We present observations of the early afterglow emission of GRB 060418. Thanks to the simultaneous coverage at optical, X-ray and gamma-ray wavelengths, we can detect and separate the external shock emission (visible in the optical and late X-ray data) and the central engine activity (early X and gamma rays). The two components are clearly distinguished based on temporal and spectral properties. The detection of the afterglow onset (in the optical) allows the determination of the fundamental fireball properties, namely its bulk Lorentz factor and total energy. The early time X-ray flare closely resembles the prompt emission gamma-ray pulses in its temporal profile, being wider at low energies and showing lags between the hard and soft bands. This provides a strong suggestion that X-ray flares are a continuation of the prompt emission.

scholarly journals Intermittent hydrodynamic jets in collapsars do not produce GRBs

2020 ◽  
Vol 495 (1) ◽  
pp. 570-577 ◽  
Author(s):  
Ore Gottlieb ◽  
Amir Levinson ◽  
Ehud Nakar
Keyword(s):  
High Efficiency ◽  
Gamma Ray ◽  
Heavy Baryon ◽  
Stellar Envelope ◽  
X Ray ◽  
Radiative Efficiency ◽  
Engine Model ◽  
Central Engine ◽  
Radio Transients ◽  
Prompt Emission

ABSTRACT Strong variability is a common characteristic of the prompt emission of gamma-ray bursts (GRB). This observed variability is widely attributed to an intermittency of the central engine, through formation of strong internal shocks in the GRB-emitting jet expelled by the engine. In this paper, we study numerically the propagation of hydrodynamic jets, injected periodically by a variable engine, through the envelope of a collapsed star. By post-processing the output of 3D numerical simulations, we compute the net radiative efficiency of the outflow. We find that all intermittent jets are subject to heavy baryon contamination that inhibits the emission at and above the photosphere well below detection limits. This is in contrast to continuous jets that, as shown recently, produce a highly variable gamma-ray photospheric emission with high efficiency, owing to the interaction of the jet with the stellar envelope. Our results challenge the variable engine model for hydrodynamic jets, and may impose constraints on the duty cycle of GRB engines. If such systems exist in nature, they are not expected to produce bright gamma-ray emission, but should appear as X-ray, optical, and radio transients that resemble a delayed GRB afterglow signal.

scholarly journals Statistical Analyses of the Energies of X-Ray Plateaus and Flares in Gamma-Ray Bursts

2022 ◽  
Vol 924 (2) ◽  
pp. 69
Author(s):  
Shuang-Xi Yi ◽  
Mei Du ◽  
Tong Liu
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Physical Origin ◽  
Radiation Mechanisms ◽  
Gaussian Distributions ◽  
Emission Energy ◽  
X Ray ◽  
Central Engine ◽  
Positive Correlations ◽  
Prompt Emission

Abstract Distinct X-ray plateau and flare phases have been observed in the afterglows of gamma-ray bursts (GRBs), and most of them should be related to central engine activities. In this paper, we collect 174 GRBs with X-ray plateau phases and 106 GRBs with X-ray flares. There are 51 GRBs that overlap in the two selected samples. We analyze the distributions of the proportions of the plateau energy E plateau and the flare energy E flare relative to the isotropic prompt emission energy E γ,iso. The results indicate that they well meet the Gaussian distributions and the medians of the logarithmic ratios are ∼−0.96 and −1.39 in the two cases. Moreover, strong positive correlations between E plateau (or E flare ) and E γ,iso with slopes of ∼0.95 (or ∼0.80) are presented. For the overlapping sample, the slope is ∼0.80. We argue that most of X-ray plateaus and flares might have the same physical origin but appear with different features because of the different circumstances and radiation mechanisms. We also test the applicabilities of two models, i.e., black holes surrounded by fractured hyperaccretion disks and millisecond magnetars, on the origins of X-ray plateaus and flares.

The coronal dividing line in the ROSAT X-ray All-Sky Survey

1991 ◽  
Vol 383 ◽  
pp. L15 ◽  
Author(s):  
Bernhard Haisch ◽  
J. H. M. M. Schmitt ◽  
C. Rosso
Keyword(s):  
X Ray ◽  
Sky Survey ◽  
Dividing Line

scholarly journals A complete sample of brightSwiftGamma-ray bursts: X-ray afterglow luminosity and its correlation with the prompt emission

2012 ◽  
Vol 425 (1) ◽  
pp. 506-513 ◽  
Author(s):  
P. D'Avanzo ◽  
R. Salvaterra ◽  
B. Sbarufatti ◽  
L. Nava ◽  
A. Melandri ◽  
...  
Keyword(s):  
Complete Sample ◽  
X Ray ◽  
Prompt Emission

scholarly journals A THREE-STAGE MODEL FOR THE INNER ENGINE OF GRBs: PROMPT EMISSION AND EARLY AFTERGLOW

2008 ◽  
Vol 17 (09) ◽  
pp. 1383-1389 ◽  
Author(s):  
J. STAFF ◽  
B. NIEBERGAL ◽  
R. OUYED
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
Surrounding Medium ◽  
Core Collapse ◽  
Stage Model ◽  
Quark Star ◽  
X Ray ◽  
Core Collapse Supernova ◽  
Stage 1 ◽  
Prompt Emission

We describe a model within the "quark-nova" scenario to interpret the recent observations of early X-ray afterglows of long gamma-ray bursts (GRBs) with the Swift satellite. This is a three-stage model within the context of a core-collapse supernova. STAGE 1 is an accreting (proto-) neutron star leading to a possible delay between the core collapse and the GRB. STAGE 2 is accretion onto a quark star, launching an ultrarelativistic jet generating the prompt GRB. This jet also creates the afterglow as the jet interacts with the surrounding medium creating an external shock. Slower shells ejected from the quark star (during accretion), can re-energize the external shock leading to a flatter segment in the X-ray afterglow. STAGE 3, which occurs only if the quark star collapses to form a black hole, consists of an accreting black hole. The jet launched in this accretion process interacts with the preceding quark star jet, and could generate the flaring activity frequently seen in early X-ray afterglows. Alternatively, a STAGE 2b can occur in our model if the quark star does not collapse to a black hole. The quark star in this case can then spin down due to magnetic braking, and the spin down energy may lead to flattening in the X-ray afterglow as well. This model seems to account for both the energies and the timescales of GRBs, in addition to the newly discovered early X-ray afterglow features.

GRB 070311: A COMMON ORIGIN FOR THE PROMPT AND AFTERGLOW EMISSION

2008 ◽  
Vol 17 (09) ◽  
pp. 1359-1362 ◽  
Author(s):  
◽  
S. D. VERGANI ◽  
C. GUIDORZI
Keyword(s):  
Light Curve ◽  
Power Law ◽  
Time Profile ◽  
Common Origin ◽  
Light Curves ◽  
X Ray ◽  
Γ Ray ◽  
Prompt Emission

GRB 070311 was a long burst that triggered INTEGRAL. We present prompt γ-ray, early NIR/optical, late optical and X-ray data on this burst and its afterglow. Interestingly, the H-band light curve acquired with REM exhibits two pulses at 80 and 140 s after the peak of the γ-ray burst, with possible evidence for a contemporaneous faint γ-ray tail. The late optical and X-ray afterglow underwent a rebrightening between 3 × 104 and 2 × 105 s after the burst with energy comparable with that of the prompt emission extrapolated in the X-ray band. After fitting the early γ-ray and optical light curves, we modelled the time profile of the late rebrightening as the time-rescaled version of the prompt γ-ray pulse over an underlying power law. This result supports a common origin for both prompt and late X-ray/optical afterglow rebrightening of GRB 070311 within the external shock scenario.

STOCHASTIC WAKEFIELD PLASMA ACCELERATION IN GAMMA-RAY BURSTS

2007 ◽  
Vol 21 (03n04) ◽  
pp. 627-632
Author(s):  
G. BARBIELLINI ◽  
F. LONGO ◽  
N. OMODEI ◽  
D. GIULIETTI ◽  
A. CELOTTI ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Plasma Acceleration ◽  
Gamma Ray Burst ◽  
Initial Burst ◽  
X Ray ◽  
Wake Field ◽  
Prompt Emission

Gamma-Ray Burst (GRB) prompt emission can, for specific conditions, be so powerful and short-pulsed to strongly influence any surrounding plasma. In this paper, we briefly discuss the possibility that a very intense initial burst of radiation produced by GRBs satisfy the intensity and temporal conditions to cause stochastic wake-field particle acceleration in a surrounding plasma of moderate density. We consider a simple but realistic GRB model for which particle wake-field acceleration can first be excited by a very strong low-energy precursor, and then be effective in producing the observed prompt X-ray and gamma-ray GRB emission.

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