Inferring the emission regions for different kinds of gamma-ray bursts
arXiv:astro-ph/0608570 · doi:10.1002/asna.200610666
Abstract
Using a theoretical model describing pulse shapes, we have clarified the relations between the observed pulses and their corresponding timescales, such as the angular spreading time, the dynamic time as well as the cooling time. We find that the angular spreading timescale caused by curvature effect of fireball surface only contributes to the falling part of the observed pulses, while the dynamic one in the co-moving frame of the shell merely contributes to the rising portion of pulses provided the radiative time is negligible. In addition, the pulses resulted from the pure radiative cooling time of relativistic electrons exhibit properties of fast rise and slow decay (a quasi-FRED) profile together with smooth peaks. Besides, we interpret the phenomena of wider pules tending to be more asymmetric to be a consequence of the difference in emission regions. Meanwhile, we find the intrinsic emission time is decided by the ratios of lorentz factors and radii of the shells between short and long bursts. Based on the analysis of asymmetry, our results suggest that the long GRB pulses may occur in the regions with larger radius, while the short bursts could locate at the smaller distance from central engine.
arXiv comment6 pages; 6 figures; accepted for publication in AN with minor changes
References in corpus (34)
- Gamma-Ray Bursts and the Fireball Model
- Gamma-Ray Bursts as the Death Throes of Massive Binary Stars
- Unsteady Outflow Models for Cosmological Gamma-Ray Bursts
- Gamma-Ray Bursts: Progress, Problems & Prospects
- Theories of Gamma-Ray Bursts
- Can internal shocks produce the variability in GRBs?
- Gamma-ray bursts from internal shocks in a relativistic wind: temporal and spectral properties
- Short Gamma-Ray Bursts with Extended Emission
- Relativistic Jets in Collapsars
- Variability in GRBs - A Clue
- Hydrodynamic Time Scales and Temporal Structure of GRBs
- Gamma-ray burst early optical afterglows: implications for the initial Lorentz factor and the central engine
- Expanding Relativistic Shells and Gamma-Ray Burst Temporal Structure
- Cooling Time Scales and Temporal Structure of Gamma-Ray Bursts
- Pulse Width Evolution in GRBs: Evidence for Internal Shocks
- Search for Relativistic Curvature Effects in Gamma-Ray Burst Pulses
- Curvature Effects in Gamma Ray Burst Colliding Shells
- Empirical Constraints on Source Properties and Host Galaxies of Cosmological Gamma-Ray Bursts
- A Compact Fireball Model of Gamma Ray Bursts
- On the Hardness-Intensity Correlation in Gamma-Ray Burst Pulses
- Spectral lags and the energy dependence of pulse width in gamma-ray bursts: contributions from the relativistic curvature effect
- Analysis of Temporal Features of Gamma Ray Bursts in the Internal Shock Model
- Temporal properties of short GRBs
- Gamma-Ray Burst Spectra and Light Curves as Signatures of a Relativistically Expanding Plasma
- Characteristics of profiles of gamma-ray burst pulses associated with the Doppler effect of fireballs
- The Connection Between Spectral Evolution and GRB Lag
- Spectral Lags of Gamma-Ray Burst From Ginga and BATSE
- GRBs Light Curves - Another Clue on the Inner Engine
- The External Shock Model of Gamma-Ray Bursts: Three Predictions and a Paradox Resolved
- Intrinsic Parameters of GRB990123 from Its Prompt Optical Flash and Afterglow
- Prompt Gamma-ray and Early Afterglow Emission in the External Shock Model
- Deviation of light curves of gamma-ray burst pulses from standard forms due to the curvature effect of spherical fireballs or uniform jets
- Physical implication of the Kocevski Ryde Liang pulse function of gamma ray bursts
- Cosmic Magnetic Fields
Cited by in corpus (7)
- Correlation between Peak Energy and Peak Luminosity in Short Gamma-Ray Bursts
- An analytic derivation of the empirical correlations of gamma-ray bursts
- On Spectral Peak Energy of Swift Gamma-Ray Bursts
- Nonthermal Synchrotron Radiation from Gamma Ray Burst External Shocks and the X-ray Flares Observed with Swift
- Detecting Radio Afterglows of Gamma-Ray Bursts with FAST
- Properties of Short GRB Pulses in the Fourth BATSE Catalog: Implications for Structure and Evolution of the Jetted Outflows
- Radio Afterglow Rebrightening: Evidence for Multiple Active Phases in Gamma-Ray Burst Central Engines