Variabilities of Gamma-Ray Burst Afterglows: Long-acting Engine, Anisotropic Jet or Many Fluctuating Regions?

Abstract

We show that simple kinematic arguments can give limits on the timescale and amplitude of variabilities in gamma-ray burst (GRB) afterglows, especially when the variability timescale is shorter than the observed time since the burst Δt < t. These limits help us to identify the sources of afterglow variability. The afterglows of GRB 011211 and GRB 021004 marginally violate these limits. If such violation is confirmed by the Swift satellite, a possible explanation is that (1) the compact objects that power GRB jets continue to eject an intermittent outflow for a very long timescale (> 1 day), (2) the GRB jet from the central engine has a temporal anisotropy with a large brightness contrast > 10 and small angular structure < 10^{-2}, or (3) many (> 10^{3}) regions fluctuate simultaneously in the emitting site.

arXiv comment13 pages, 1 figure, accepted for publication in ApJ

References in corpus (53)

• Spectra and Light Curves of Gamma-Ray Burst Afterglows
• Beaming in Gamma-Ray Bursts: Evidence for a Standard Energy Reservoir
• Gamma-Ray Bursts: Progress, Problems & Prospects
• Supernovae, Jets, and Collapsars
• Theories of Gamma-Ray Bursts
• The unusual afterglow of GRB 980326: evidence for the gamma-ray burst/supernova connection
• Viewing Angle and Environment Effects in GRB: Sources of Afterglow Diversity
• Refreshed Shocks and Afterglow Longevity in GRB
• Variability in GRBs - A Clue
• Gamma-Ray Burst Afterglow: Polarization and Analytic Light Curves
• Impulsive and Varying Injection in GRB Afterglows
• Expanding Relativistic Shells and Gamma-Ray Burst Temporal Structure
• Multi-Wavelength Afterglows in Gamma-Ray Bursts: Refreshed Shock and Jet Effects
• The Evolution of a Structured Relativistic Jet and GRB Afterglow Light-Curves
• The Signature of Supernova Ejecta Measured in the X-ray Afterglow of Gamma-Ray Burst 011211
• The afterglow of GRB 021004: surfing on density waves
• On the Nature of Nonthermal Radiation from Cosmological Gamma-Ray Bursters
• BVRI Observations of the Optical Afterglow of GRB 990510
• Some Observational Consequences of GRB Shock Models
• Angular size and emission time scales of relativistic fireballs
• Peak Luminosity-Spectral Lag Relation Caused by the Viewing Angle of the Collimated Gamma-Ray Bursts
• Gamma-ray bursts with continuous energy injection and their afterglow signature
• GRB 021004: Reverse Shock Emission
• Energetics and Luminosity Function of Gamma-ray Bursts
• The detailed optical light curve of GRB 030329
• The Variable Light Curve of GRB 030329: The Case for Refreshed Shocks
• The Observed Size and Shape of GRB Afterglow
• Variability in GRB Afterglows and GRB 021004
• Iron K-alpha Emission from a Decaying Magnetar Model of Gamma-Ray Bursts
• Rings in Fireball Afterglows
• A Unified Model of Short and Long Gamma-Ray Bursts, X-Ray Rich Gamma-Ray Bursts, and X-Ray Flashes
• Resolving Gamma-Ray Burst 000301C with a Gravitational Microlens
• Hydrodynamics of Relativistic Blast Waves in a Density-Jump Medium and Their Emission Signature
• Dust Echos from Gamma Ray Bursts
• Variability of GRB Afterglows Due to Interstellar Turbulence
• Microlensing of $\gamma$-Ray Burst Afterglows
• The Optical Afterglow of GRB 011211
• The Optical Afterglows of Gamma-Ray Bursts
• The unusual optical afterglow of the gamma-ray burst GRB 021004: Color changes and short-time-scale variability
• A Numerical Gamma-Ray Burst Simulation Using Three-Dimensional Relativistic Hydrodynamics: The Transition from Spherical to Jet-like Expansion
• Structure in the early afterglow lightcurve of the gamma-ray burst of 29 March 2003
• Polarization and light curve variability: the "patchy shell" model
• Broadband Modeling of GRB 021004
• Chromatic Signatures in the Microlensing of GRB Afterglows
• Small-scale variations in the radiating surface of the GRB 011211 jet
• GRB 020813: polarization in the case of a smooth optical decay
• Earliest detection of the optical afterglow of GRB 030329 and its variability
• High-Precision Photometry of the Gamma-Ray Burst 020813: The Smoothest Afterglow Yet
• The Earliest Optical Observations of GRB 030329
• Microlensing of collimated Gamma-Ray Burst afterglows
• Identifying young gamma-ray burst fossils
• Delayed X-Ray Afterglows from Obscured Gamma-Ray Bursts in Star-Forming Regions
• Early ($<$0.3 day) R-band light curve of the optical afterglow of GRB030329

Cited by in corpus (126)

• Gamma-Ray Bursts
• Physical processes shaping GRB X-ray afterglow lightcurves: theoretical implications from the Swift XRT observations
• The Physics of Gamma-Ray Bursts and Relativistic Jets
• Gamma-Ray Bursts in the Swift Era
• A new population of ultra-long duration gamma-ray bursts
• GRB Radiative Efficiencies Derived from the Swift Data: GRBs vs. XRFs, Long vs. Short
• An embedded X-ray source shines through the aspherical AT2018cow: revealing the inner workings of the most luminous fast-evolving optical transients
• A Complete Reference of the Analytical Synchrotron External Shock Models of Gamma-Ray Bursts
• The First Survey of X-ray Flares from Gamma Ray Bursts Observed by Swift: Temporal Properties and Morphology
• Testing the Curvature Effect and Internal Origin of Gamma-Ray Burst Prompt Emissions and X-ray Flares with Swift Data
• Late internal shock model for bright X-ray flares in Gamma-ray Burst afterglows and GRB 011121
• A Comprehensive Analysis of Swift/XRT Data: III. Jet Break Candidates in X-ray and Optical Afterglow Lightcurves
• Unveiling the origin of X-ray flares in Gamma-Ray Bursts
• The Giant X-ray Flare of GRB 050502B: Evidence for Late-Time Internal Engine Activity
• Short GRB 160821B: a reverse shock, a refreshed shock, and a well-sampled kilonova
• How Bad/Good Are the External Forward Shock Afterglow Models of Gamma-Ray Bursts?
• A long-lived neutron star merger remnant in GW170817: constraints and clues from X-ray observations
• Opening Angles of Collapsar Jets
• Open Questions in GRB Physics
• High energy neutrino early afterglows from gamma-ray bursts revisited
• Efficiency Crisis of Swift Gamma-Ray Bursts with Shallow X-ray Afterglows: Prior Activity or Time-Dependent Microphysics?
• How Long does a Burst Burst?
• High-Energy Neutrino Emission from Short Gamma-Ray Bursts: Prospects for Coincident Detection with Gravitational Waves
• X-ray flare in XRF 050406: evidence for prolonged engine activity
• X-ray flares and the duration of engine activity in gamma-ray bursts
• X-ray Hardness Evolution in GRB Afterglows and Flares: Late Time GRB Activity Without N_H Variations
• Smooth Light Curves from a Bumpy Ride: Relativistic Blast Wave Encounters a Density Jump
• The Onset of Gamma-Ray Burst Afterglow
• Three-Dimensional Simulations of MHD Turbulence Behind Relativistic Shock Waves and Their Implications for GRBs
• High Energy Neutrino Flashes from Far-Ultraviolet and X-ray Flares in Gamma-Ray Bursts
• Low-Luminosity GRB 060218: A Collapsar Jet from a Neutron Star, Leaving a Magnetar as a Remnant?
• Gamma-Ray Burst Science in the Era of the Cherenkov Telescope Array
• Early Afterglows of Gamma-Ray Bursts in a Stratified Medium with a Power-Law Density Distribution
• Constraining GRB Emission Physics with Extensive Early-Time, Multiband Follow-up
• Late-time Evolution of Afterglows from Off-Axis Neutron-Star Mergers
• Modeling Gamma-Ray Burst X-Ray Flares within the Internal Shock Model
• GRB 060313: A New Paradigm for Short-Hard Bursts?
• X-ray flare candidates in short gamma-ray bursts
• The two-component jet of GRB 080413B
• Double Neutron Star Mergers and Short Gamma-Ray Bursts: Long-Lasting High-Energy Signatures and Remnant Dichotomy
• Gamma-Ray Burst long lasting X-ray flaring activity
• Inverse Compton X-ray Flare from GRB Reverse Shock
• On the Implications of Late Internal Dissipation for Shallow-Decay Afterglow Emission and Associated High-Energy Gamma-Ray Signals
• Bimodal Long-Lasting Components in Short Gamma-Ray Bursts: Promising Electromagnetic Counterparts to Neutron Star Binary Mergers
• Multi-wavelength observations of the energetic GRB 080810: detailed mapping of the broadband spectral evolution
• The optical flare and afterglow light curve of GRB 050904 at redshift z=6.29
• First ALMA Light Curve Constrains Refreshed Reverse Shocks and Jet Magnetization in GRB 161219B
• Long-Lasting Black-Hole Jets in Short Gamma-Ray Bursts
• Optical and X-Ray Observations of GRB 060526: A Complex Afterglow Consistent with An Achromatic Jet Break
• Unusual Central Engine Activity in the Double Burst GRB 110709B
• X-ray Flares in Early GRB Afterglows
• External Inverse-Compton and Proton Synchrotron Emission from the Reverse Shock as the Origin of VHE Gamma-Rays from the Hyper-Bright GRB 221009A
• On the nature of late X-ray flares in Swift Gamma-ray Bursts
• Tail Emission of Prompt Gamma-Ray Burst Jets
• Energy Sources and Light Curves of Macronovae
• The Afterglow and Environment of the Short GRB111117A
• Prospects for Detecting Gamma-Ray Bursts at Very High Energies with the Cherenkov Telescope Array
• Peculiar prompt emission and afterglow in H.E.S.S. detected GRB 190829A
• GRB 060714: No Clear Dividing Line Between Prompt Emission and X-ray Flares
• Pulse Width Evolution of Late Time X-rays Flares in GRBs: Evidence For Internal Shocks
• Is the macronova in GW170817 powered by the central engine?
• The high-redshift gamma-ray burst GRB140515A
• Constraints on the Bulk Lorentz Factors of GRB X-Ray Flares
• GRB 070311: a direct link between the prompt emission and the afterglow
• Rapid X-ray Declines and Plateaus in Swift GRB Light Curves Explained by A Highly Radiative Blast Wave
• Gamma-ray burst afterglows
• Is GRB afterglow emission intrinsically anisotropic ?
• No flares from Gamma-Ray Burst afterglow blast waves encountering sudden circumburst density change
• X-ray flares from propagation instabilities in long Gamma-Ray Burst jets
• Flares in Gamma Ray Bursts: Disc Fragmentation and Evolution
• Disparate MgII Absorption Statistics towards Quasars and Gamma-Ray Bursts : A Possible Explanation
• The Swift X-ray flaring afterglow of GRB 050607
• Dead Zone Formation and Nonsteady Hyperaccretion in Collapsar Disks : A Possible Origin of Short-Term Variability in the Prompt Emission of Gamma-Ray Bursts
• GRB 170817A as a Refreshed Shock Afterglow viewed off-axis
• Isotropic Detectable X-ray Counterparts to Gravitational Waves from Neutron Star Binary Mergers
• Testing the External Shock Model of Gamma-Ray Bursts using the Late-Time Simultaneous Optical and X-ray Afterglows
• Upscattered Cocoon Emission in Short Gamma-ray Bursts as High-energy Gamma-ray Counterparts to Gravitational Waves
• The nature of the late achromatic bump in GRB 120326A
• Gamma-ray Burst Flares: X-ray Flaring. II
• Central Engine of Late-Time X-ray Flares with Internal Origin
• Closure Relations for Electron-Positron Pair-Signatures in Gamma-Ray Bursts
• Long term flaring activity of XRF 011030 observed with BeppoSAX
• X-raying extended emission and rapid decay of short gamma-ray bursts
• The afterglow and host galaxy of GRB 090205: evidence for a Ly-alpha emitter at z=4.65
• Limits on optical polarization during the prompt phase of GRB 140430A
• The exceptionally extended flaring activity in the X-ray afterglow of GRB 050730 observed with Swift and XMM-Newton
• Probing GRB environments with time variability: ULTRASPEC fast imaging of GRB 080210
• Linking extended and plateau emissions of short gamma-ray bursts
• Delayed jet breakouts from binary neutron star mergers
• GRB 180620A: Evidence for late-time energy injection
• Nonthermal Synchrotron Radiation from Gamma Ray Burst External Shocks and the X-ray Flares Observed with Swift
• The long-active afterglow of GRB 210204A: Detection of the most delayed flares in a Gamma-Ray Burst
• Reverse Shock Emission in Gamma-ray Bursts Revisited
• Gamma-Ray Bursts with Extended Emission: Classifications, Energy Correlations and Radiation Properties
• Fallback Accretion Halted by R-process Heating in Neutron Star Mergers and Gamma-Ray Bursts
• Diagnosing the remnants of binary neutron star merger from GW170817/GRB170817A event
• GRB 050713A: High Energy Observations of the GRB Prompt and Afterglow Emission
• GRB X-Ray Flare Properties among Different GRB Subclasses
• GRB 050822: Detailed analysis of an XRF observed by Swift
• Diversity of multiwavelength emission bumps in the GRB 100219A afterglow
• Infrared/optical - X-ray simultaneous observations of X-ray flares in GRB 071112C and GRB 080506
• Modelling the prompt optical emission of GRB 180325A: the evolution of a spike from the optical to gamma-rays
• The Signature of Refreshed Shocks in the of Afterglow of GRB030329
• Late X-ray flares from the interaction of a reverse shock with a stratified ejecta in GRB afterglows: simulations on a moving mesh
• High-energy neutrino emission associated with gravitational-wave signals: effects of cocoon photons and constraints on late-time emission
• A multi band study of the optically dark GRB 051028
• Bright gamma-ray flares observed in GRB131108A
• Structured Jet Model for Multiwavelength Observations of the Jetted Tidal Disruption Event AT 2022cmc
• Magnetar Giant Flare Originated GRB 200415A: Transient GeV emission, Time-Resolved ${\mathrm{E}}_{\mathrm{p}}-{\mathrm{L}}_{\mathrm{iso}}$ Correlation, and Implications
• Multi-messenger detection prospects of gamma-ray burst afterglows with optical jumps
• The unusual X-ray light-curve of GRB 080307: the onset of the afterglow?
• Central Engine-Powered Bright X-ray Flares in Short Gamma-Ray Bursts: A Hint of Black Hole-Neutron Star Merger?
• High time resolution search for prompt radio emission from the long GRB 210419A with the Murchison Widefield Array
• Revisiting X-ray Afterglows of Jetted Tidal Disruption Events with the External Reverse Shock
• Late Engine Activity of GRB 161017A Revealed by Early Optical Observations
• HETE-2 Observations of the X-Ray Flash XRF 040916
• GRB090111: extra soft steep decay emission and peculiar re-brightening
• Observations of GRB 060526 Optical Afterglow with Russian-Turkish 1.5-m Telescope
• Unveiling the nature of the Einstein Probe transient EP 241021a
• Viscous Evolution of Magnetized Clumps: a Source for X-ray Flares in Gamma-ray Bursts
• High-energy emissions from neutron star mergers
• Swift highlights and flares (Back to the drawing board?)
• A lower occurrence rate of bright X-ray flares in SN-GRBs than $z<1$ GRBs: evidence of energy partitions?
• Revisiting early afterglows of gamma-ray bursts with finite-thickness ejecta: Implications from XRF 080330 and GRB 080710
• Predicting Multiwavelength Emission Associated with X-Ray Flares and Extended Emission of Gamma-Ray Bursts
• On the Variability of Gamma-Ray Burst Afterglows - A Possibility of a Transition to Nonrelativistic Motion