Prompt GRB emission from gradual energy dissipation

By D. Giannios. 2007

181 citations recorded by the source corpus.

I calculate the emission expected from a Poynting-flux-dominated gamma-ray burst (GRB) flow in which energy is dissipated gradually by magnetic reconnection. In this picture, the energy of the radiating particles is determined by heating and cooling balance (slow heating model). Detailed radiative transfer calculations show that, at Thomson optical depths of order of unity, the dominant radiative process is inverse Compton scattering. Synchrotron-self-absorbed emission and inverse Compton dominate in the Thomson thin parts of the flow. The electrons stay thermal throughout the dissipation region because of Coulomb collisions (Thomson thick part of the flow) and exchange of synchrotron photons (Thomson thin part). The resulting spectrum naturally explains the observed sub-MeV break of the GRB emission and the spectral slopes above and below the break. The model predicts that the γ-ray power-law tail has a high-energy cutoff typically in the ∼0.1−1 GeV energy range that should be observable with GLAST. The model also predicts a prompt emission component in the optical and UV associated with the GeV emission. Observations of the prompt emission of GRB 061121 that cover the energy range from the optical to ∼1 MeV are explained by the model.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b8006c2a94a2edf8991400e9776fe170a0b853eb

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In Astronomy and Astrophysics

1. Bing Zhang
2. Pawan Kumar
3. B. Metzger
4. D. Giannios
5. E. Quataert
6. A. Tchekhovskoy
7. L. Sironi
8. E. Liang

Citations in the corpus

• DISCERNING THE PHYSICAL ORIGINS OF COSMOLOGICAL GAMMA-RAY BURSTS BASED ON MULTIPLE OBSERVATIONAL CRITERIA: THE CASES OF z = 6.7 GRB 080913, z = 8.2 GRB 090423, AND SOME SHORT/HARD GRBs (2009, background): “If dissipation occurs at small radii, the effect is to modify the photosphere emission through continuous heating (Giannios 2008).”
• QUASI-BLACKBODY COMPONENT AND RADIATIVE EFFICIENCY OF THE PROMPT EMISSION OF GAMMA-RAY BURSTS (2008, background): “In such a scenario, Giannios & Spruit (2007) and Giannios (2008) have shown how the fraction of thermal emission in the spectrum varies with the Lorentz factor of the outflow.”
• Relativistic MHD simulations of core-collapse GRB jets: 3D instabilities and magnetic dissipation (2015, background): “However, the non-thermal emission observed in many GRBs likely requires additional dissipation to occur close to or beyond the photosphere (see, e.g., Giannios 2008).”
• The physics of gamma-ray bursts & relativistic jets (2014, background): “Alternatively, photons can be generated at the photosphere (Rees and Mészáros, 2005; Pe’er et al., 2006b; Thompson et al., 2007; Pe’er, 2008; Giannios, 2008; Beloborodov, 2010; Lazzati and Begelman, 2010; Ioka, 2010) or from magnetic field dissipation beyond the internal shock radii (Lyutikov and…”
• THE INTERNAL-COLLISION-INDUCED MAGNETIC RECONNECTION AND TURBULENCE (ICMART) MODEL OF GAMMA-RAY BURSTS (2010, methodology): “In the past, the GRB prompt emission models in the MHD regime (Spruit et al. 2001; Drenkhahn 2002; Drenkhahn and Spruit 2002; Vlahakis and Königl 2003; Giannios 2008) have been “semi-fireball” like.”
• Plasmoids in relativistic reconnection, from birth to adulthood: first they grow, then they go (2016, background): “…Sironi & Spitkovsky 2011a), jets from active galactic nuclei (AGNs; e.g.,Romanova & Lovelace 1992; Giannios et al. 2009, 2010; Giannios 2013) and gamma-ray bursts (GRBs; e.g.,Thompson 1994, 2006; Usov 1994; Spruit et al. 2001; Drenkhahn & Spruit 2002; Lyutikov & Blandford 2003; Giannios 2008).”
• RELATIVISTIC RECONNECTION: AN EFFICIENT SOURCE OF NON-THERMAL PARTICLES (2014, background): “…& Kirk 2001; Lyubarsky 2003; Kirk & Skjæraasen 2003; Pétri & Lyubarsky 2007), jets from active galactic nuclei (AGNs; Romanova & Lovelace 1992; Giannios et al. 2009; Giannios 2013) and gammaray bursts (GRBs; Thompson 1994, 2006; Spruit et al. 2001; Lyutikov & Blandford 2003; Giannios 2008).”
• A Reconnection Switch to Trigger gamma-Ray Burst Jet Dissipation (2010, background): “In the transition from optically-thick to optically-thin radiation, synchrotron at low frequencies can be self-absorbed leading to a dominant Comptonized emission (Giannios 2008; Lazzati & Begelman 2010).”
• The Proto-Magnetar Model for Gamma-Ray Bursts (2010, methodology): “We follow the model of Giannios (2006, 2008), who assumes that the dissipated energy heats the plasma smoothly throughout the flow (slow heating model; see Ghisellini & Celotti 1999; Stern & Poutanen 2004).”