The Photosphere Emission Spectrum of Hybrid Relativistic Outflow for Gamma-ray Bursts

Abstract

The photospheric emission in the prompt phase is the natural prediction of the original fireball model for gamma-ray burst (GRB) due to the large optical depth ($\tau >1$) at the base of the outflow, which is supported by the quasi-thermal components detected in several Fermi GRBs. However, which radiation mechanism (photosphere or synchrotron) dominates in most GRB spectra is still under hot debate. The shape of the observed photosphere spectrum from a pure hot fireball or a pure Poynting-flux-dominated outflow has been investigated before. In this work, we further study the photosphere spectrum from a hybrid outflow containing both a thermal component and a magnetic component with moderate magnetization (${\sigma }_0=L_P/L_{\text{Th}}\sim 1-10$), by invoking the probability photosphere model. The high-energy spectrum from such a hybrid outflow is a power law rather than an exponential cutoff, which is compatible with the observed Band function in large amounts of GRBs. Also, the distribution of the low-energy indices (corresponding to the peak-flux spectra) is found to be quite consistent with the statistical result for the peak-flux spectra of GRBs best-fitted by the Band function, with similar angular profiles of structured jet in our previous works. Finally, the observed distribution of the high-energy indices can be well understood after considering the different magnetic acceleration (due to magnetic reconnection and kink instability) and the angular profiles of dimensionless entropy with the narrower core.

14 pages, 10 figures, published in MNRAS

References in corpus (40)

• The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts
• Magnetic acceleration of ultra-relativistic jets in gamma-ray burst sources
• GRB Radiative Efficiencies Derived from the Swift Data: GRBs vs. XRFs, Long vs. Short
• Detection of a Thermal Spectral Component in the Prompt Emission of GRB 100724B
• A Comprehensive Analysis of Fermi Gamma-Ray Burst Data. I. Spectral Components and Their Possible Physical Origins of LAT/GBM GRBs
• Prompt GRB emission from gradual energy dissipation
• GRB110721A: An extreme peak energy and signatures of the photosphere
• Temporal Evolution Of Thermal Emission From Relativistically Expanding Plasma
• The role of kink instability in Poynting-flux dominated jets
• Quasi-blackbody component and radiative efficiency of the prompt emission of gamma-ray bursts
• Hyper-accreting black hole as GRB central engine. I: Baryon loading in GRB jets
• A Comprehensive Analysis of Fermi Gamma-ray Burst Data: II. $E_{\mathrm{p}}$-Evolution Patterns and Implications for the Observed Spectrum-Luminosity Relations
• Prompt emission spectra from the photosphere of a GRB
• A Comparison of the Afterglows of Short- and Long-Duration Gamma-Ray Bursts
• The structure of hydrodynamic $\gamma$-ray burst jets
• Photosphere emission from a hybrid relativistic outflow with arbitrary dimensionless entropy and magnetization in GRBs
• The Properties of Short gamma-ray burst Jets Triggered by neutron star mergers
• The Prompt Gamma-Ray and Afterglow Energies of Short-Duration Gamma-Ray Bursts
• The width of gamma-ray burst spectra
• Low-energy Spectra of Gamma-ray Bursts from Cooling Electrons
• Thermal Radiation from GRB Jets
• The photospheric radiation model for the prompt emission of Gamma-ray Bursts: Interpreting four observed correlations
• GRB 200415A: A Short Gamma-Ray Burst from a Magnetar Giant Flare?
• Relativistic MHD simulations of collision-induced magnetic dissipation in Poynting-flux-dominated jets/outflows
• Poynting flux dominated jets challenged by their photospheric emission
• Propagation of a Short GRB Jet in the Ejecta: Jet Launching Delay Time, Jet Structure, and GW170817/GRB 170817A
• Evidence for jet launching close to the black hole in GRB 101219B - a Fermi GRB dominated by thermal emission
• The Fraction of Gamma-ray Bursts with an Observed Photospheric Emission Episode
• A global numerical model of the prompt emission in short gamma-ray bursts
• Synchrotron radiation in $\gamma$-ray burst prompt emission
• Emission from accelerating jets in gamma-ray bursts: Radiation dominated flows with increasing mass outflow rates
• Jet Structure in the Afterglow Phase for Gamma-ray Bursts with a Precessing Jet
• Dissecting the Energy Budget of a Gamma-Ray Burst Fireball
• Gamma-Ray Burst jet dynamics and their interaction with the progenitor star
• Origin for the Prompt Spectral Evolution Characteristics and High Energy Emission during the X-Ray Flare in GRB 180720B
• A Spectral Analysis of Fermi-LLE GRBs
• A Bayesian Fermi-GBM Short GRB Spectral Catalog
• Rarefaction wave in relativistic steady magnetohydrodynamic flows
• {\em Fermi}/GBM Short Gamma-ray Burst Catalog and Case Study for GRB 170817A/GW 170817
• Photospheric Emission in Gamma-ray Bursts: Variability

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