X-ray flares from propagation instabilities in long Gamma-Ray Burst jets

Abstract

We present a numerical simulation of a gamma-ray burst jet from a long-lasting engine in the core of a 16 solar mass Wolf-Rayet star. The engine is kept active for 6000 s with a luminosity that decays in time as a power-law with index -5/3. Even though there is no short time-scale variability in the injected engine luminosity, we find that the jet's kinetic luminosity outside the progenitor star is characterized by fluctuations with relatively short time scale. We analyze the temporal characteristics of those fluctuations and we find that they are consistent with the properties of observed flares in X-ray afterglows. The peak to continuum flux ratio of the flares in the simulation is consistent with some, but not all, the observed flares. We propose that propagation instabilities, rather than variability in the engine luminosity, are responsible for the X-ray flares with moderate contrast. Strong flares such as the one detected in GRB 050502B, instead, cannot be reproduced by this model and require strong variability in the engine activity.

6 pages, MNRAS in press

References in corpus (11)

• The First Survey of X-ray Flares from Gamma Ray Bursts Observed by Swift: Temporal Properties and Morphology
• Fallback and Black Hole Production in Massive Stars
• The First Survey of X-ray Flares from Gamma Ray Bursts Observed by Swift: Spectral Properties and Energetics
• Very high efficiency photospheric emission in long duration gamma-ray bursts
• Relativistic Jets and Long-Duration Gamma-ray Bursts from the Birth of Magnetars
• Fragmentation of Collapsar Disks and the Production of Gravitational Waves
• X-ray flares and the duration of engine activity in gamma-ray bursts
• A unifying view of Gamma Ray Burst Afterglows
• The X-ray afterglow of the short gamma ray burst 050724
• Flares in GRB afterglows from delayed magnetic dissipation
• X-ray flares, neutrino cooled disks, and the dynamics of late accretion in GRB engines

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• X-ray flare candidates in short gamma-ray bursts
• Are Ultra-long Gamma-Ray Bursts different?
• High-efficiency photospheric emission of long-duration gamma-ray burst jets: the effect of the viewing angle
• Radial Angular Momentum Transfer and Magnetic Barrier for Short-Type Gamma-Ray Burst Central Engine Activity
• The Afterglow and Environment of the Short GRB111117A
• Time evolution of flares in GRB 130925A: jet precession in black hole accretion system
• Neutrino-cooled Accretion Model with Magnetic Coupling for X-ray Flares in GRBs
• Self-gravity in neutrino-dominated accretion disks
• Flares in Gamma Ray Bursts: Disc Fragmentation and Evolution
• Statistical analyses on the energies of X-ray plateaus and flares in gamma-ray bursts
• Swift and Fermi observations of X-ray flares: the case of Late Internal Shock
• Central Engine of Late-Time X-ray Flares with Internal Origin
• Simulations of Accretion Powered Supernovae in the Progenitors of Gamma Ray Bursts
• GRB X-Ray Flare Properties among Different GRB Subclasses
• Early GRB afterglows from reverse shocks in ultra-relativistic long-lasting winds
• Exploring GRBs and supernovae connection: does a superluminous hypernova population exist?
• Afterglows after Swift
• Comparative Statistical Analysis of Prompt and Afterglow X-Ray Flares in Gamma-Ray Bursts: Insights into Extended Central Engine Activity