Is Thermal Emission in Gamma-Ray Bursts Ubiquitous?

By F. Ryde. 2005

196 citations recorded by the source corpus.

The prompt emission of gamma-ray bursts has yet defied any simple explanation, despite the presence of rich observational material and great theoretical efforts. Here we show that all the types of spectral evolution and spectral shapes that have been observed can indeed be described with one and the same model, namely, a hybrid model with a thermal and a nonthermal component. We further show that the thermal component is the key emission process determining the spectral evolution. Even though bursts appear to have a variety of sometimes complex spectral evolutions, the behaviors of the two separate components are remarkably similar for all bursts, with the temperature describing a broken power law in time. The nonthermal component is consistent with emission from a population of fast-cooling electrons emitting optically thin synchrotron emission or nonthermal Compton radiation. This indicates that these behaviors are the fundamental and characteristic ones for gamma-ray bursts.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/09bb48fd71a9002707c077b1b17551d1787e05d0

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In Astronomy and Astrophysics

1. Bing Zhang
2. B. Metzger
3. Pawan Kumar
4. E. Quataert
5. D. Giannios
6. A. Pe’er
7. F. Ryde
8. T. Thompson

Citations in the corpus

• GRB110721A: AN EXTREME PEAK ENERGY AND SIGNATURES OF THE PHOTOSPHERE (2012, background): “It was further argued in Ryde (2005) that the spectral break in apparently nonthermal spectra can be interpreted as the photospheric emission peak.”
• DETECTION OF A THERMAL SPECTRAL COMPONENT IN THE PROMPT EMISSION OF GRB 100724B (2010, background): “Observationally, Ghirlanda et al. (2003), Ryde (2004, 2005), and Ryde et al. (2010) argued that a photospheric component is present in CGRO BATSE data.”
• 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): “2002, ApJ, 571, 779 Panaitescu, A., Kumar, P., & Narayan, R. 2001, ApJ, 561, L171 Panaitescu, A., & Mészáros, P. 1999, ApJ, 526, 707 Pe’er, A., Mészáros, P., & Rees, M. J. 2006, ApJ, 642, 995 Pe’er, A. et al. 2007, ApJ, 664, L1 Perez-Ramirez, D. et al. 2008, A&A, submitted (ArXiv:0810.2107) Perl”
• IDENTIFICATION AND PROPERTIES OF THE PHOTOSPHERIC EMISSION IN GRB090902B (2009, background): “Ryde (2005) suggested that GRB spectra are a superposition of two spectral components: photospheric blackbody emission and an accompanying nonthermal component.”
• EVIDENCE OF AN INITIALLY MAGNETICALLY DOMINATED OUTFLOW IN GRB 080916C (2009, background): “Another suggestion is that the observed GRB spectra are the superposition of a thermal component (photosphere) that defines Ep and a non-thermal power law component (Ryde 2005; Ryde & Pe’er 2008).”
• The role of kink instability in Poynting-flux dominated jets (2006, background): “The role of the photospheric component and its connection to the observed spectral peaks of the GRB prompt emission in internal shock and slow dissipation models (like this one) has been studied in a number of recent papers (Ryde 2005; Rees & Mészáros 2005; Pe’er et al. 2005).”
• A theory of photospheric emission from relativistic, collimated outflows (2012, background): “This bump is commonly interpreted as photospheric emission (e.g. Ryde 2005).”
• Prompt emission spectra from the photosphere of a GRB (2006, background): “Quasi-thermal emission has been observed in a fraction of GRBs (Ryde 2004; 2005) and they may be a result of low σ0 (i.e. high baryon loading).”
• The Ep,i–Eiso correlation in gamma-ray bursts: updated observational status, re-analysis and main implications (2006, background): “…which is currently the subject of many theoretical works, is that a substantial contribution to prompt radiation of GRBs comes from direct or Comptonized thermal emission from the photosphere of the fireball (Zhang & Mészáros 2002; Ryde 2005; Rees & Meśzaŕos 2005; Ramirez–Ruiz 2005).”
• THE INTERNAL-COLLISION-INDUCED MAGNETIC RECONNECTION AND TURBULENCE (ICMART) MODEL OF GAMMA-RAY BURSTS (2010, background): “…the observed Band-function is the nonthermal component powered by internal shocks, and the photosphere component is either below or above the detector energy band; (2) the observed Band function is the superposition of a thermal component and a nonthermal component (Ryde 2005; Ryde and Pe’er 2009).”
• Gamma-Ray Bursts in the Swift Era (2007, background): “– Ryde (2005) argues that the so-called Band-function of GRB spectrum can be actually decomposed into the combination of a thermal and a non-thermal component.”
• A Reconnection Switch to Trigger gamma-Ray Burst Jet Dissipation (2010, background): “This may help identify why some fraction of events seem to have thermal peaks (Ryde 2005).”
• The Proto-Magnetar Model for Gamma-Ray Bursts (2010, background): “The jet propagates through the star at a significant fraction β of the speed of light (e.g. MacFadyen & Woosley 1999; Aloy et al. 2000; Ramirez-Ruiz et al. 2002; Zhang et al. 2003; Morsony et al. 2007; Bucciantini et al. 2008), such that it ‘breaks out’ of the stellar surface of radius R⋆ on a times”
• Temporal Evolution of Thermal Emission from Relativistically Expanding Plasma (2008, background): “As was shown by Ryde (2004, 2005), after ∼ 1−3 s the temperature of the thermal component decreases as a power law in time, T ob.”
• Collisional mechanism for gamma‐ray burst emission (2009, background): “Observational search for this emission usually assumed that it has a quasi-thermal spectrum (e.g. Ryde 2005).”
• QUASI-BLACKBODY COMPONENT AND RADIATIVE EFFICIENCY OF THE PROMPT EMISSION OF GAMMA-RAY BURSTS (2008, methodology): “This is consistent with the findings in the works by Ryde (2004, 2005).”
• A New Method of Determining the Initial Size and Lorentz Factor of Gamma-Ray Burst Fireballs Using a Thermal Emission Component (2007, background): “…increasing evidence has appeared that, during the first stages of the prompt emission of long duration gamma-ray bursts (GRBs), a thermal component accompanies the underlying non-thermal emission [Ryde (2004, 2005); Campana et al. (2006); see also Ghirlanda et al. (2003); Kaneko et al. (2003)].”