THE INTERNAL-COLLISION-INDUCED MAGNETIC RECONNECTION AND TURBULENCE (ICMART) MODEL OF GAMMA-RAY BURSTS

By Bing Zhang, Huirong Yan. 2010

538 citations recorded by the source corpus.

The recent Fermi observation of GRB 080916C shows that the bright photosphere emission associated with a putative fireball is missing, which suggests that the central engine likely launches a Poynting-flux-dominated (PFD) outflow. We propose a model of gamma-ray burst (GRB) prompt emission in the PFD regime, namely, the Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART) model. It is envisaged that the GRB central engine launches an intermittent, magnetically dominated wind, and that in the GRB emission region, the ejecta is still moderately magnetized (e.g., 1 ≲ σ ≲ 100). Similar to the internal shock (IS) model, the mini-shells interact internally at the radius RIS ∼ Γ2cΔt. Most of these early collisions, however, have little energy dissipation, but serve to distort the ordered magnetic field lines entrained in the ejecta. At a certain point, the distortion of magnetic field configuration reaches the critical condition to allow fast reconnection seeds to occur, which induce relativistic MHD turbulence in the interaction regions. The turbulence further distorts field lines easing additional magnetic reconnections, resulting in a runway release of the stored magnetic field energy (an ICMART event). Particles are accelerated either directly in the reconnection zone, or stochastically in the turbulent regions, which radiate synchrotron photons that power the observed gamma rays. Each ICMART event corresponds to a broad pulse in the GRB light curve, and a GRB is composed of multiple ICMART events. This model retains the merits of IS and other models, but may overcome several difficulties/issues faced by the IS model (e.g., low efficiency, fast cooling, electron number excess, Amati/Yonetoku relation inconsistency, and missing bright photosphere). Within this model, the observed GRB variability timescales could have two components, one slow component associated with the central engine time history, and another fast component associated with relativistic magnetic turbulence in the emission region. The model predicts a decrease of gamma-ray polarization degree and Ep in each ICMART event (broad pulse) during the prompt GRB phase, as well as a moderately magnetized external reverse shock. The model may be applied to the GRBs that have time-resolved, featureless Band-function spectra, such as GRB 080916C and most GRBs detected by Fermi LAT.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/072277415f8ac0b48ab351d8ec8a70933d3354df

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In Astronomy and Astrophysics

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

In Nuclear and High Energy Physics

1. Bing Zhang
2. B. Metzger
3. Pawan Kumar
4. E. Quataert
5. D. Giannios
6. L. Sironi
7. M. Petropoulou
8. N. Bucciantini

Citations in the corpus

• The Proto-Magnetar Model for Gamma-Ray Bursts (2010, background): “…either indirectly by refreshing the forward shock (e.g. Granot & Kumar 2006; Dall’Osso et al. 2010) or directly (‘internally’) by e.g. forced reconnection at the forward shell (e.g. Lyubarsky 2003, 2005; Thompson 2006; Zhang & Yan 2011) or by upscattering forward shock photons (Panaitescu 2008).”
• The Observer's Guide to the Gamma-Ray Burst-Supernova Connection (2016, background): “Instead, alternative scenarios in the context of the ultra-relativistic jet model are the photospheric emission model [369, 370, 371, 372, 373], and the Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART) model [374, 375].”
• FAST MAGNETIC RECONNECTION AND SPONTANEOUS STOCHASTICITY (2011, methodology): “For instance, the LV99 model of reconnection was invoked to explain gamma ray bursts (Lazarian et al. 2002; Zhang & Yan 2011), acceleration of cosmic rays (de Gouveia Dal Pino & Lazarian 2003; Lazarian 2005; Lazarian & Opher 2009; Lazarian & Desiati 2010), removal of magnetic field during star…”
• EARLY X-RAY AND OPTICAL AFTERGLOW OF GRAVITATIONAL WAVE BURSTS FROM MERGERS OF BINARY NEUTRON STARS (2012, background): “Assuming that the magnetic energy is abruptly converted to the internal energy of power-law distributed electrons (such as in the scenario of the ICMART model), one can generally estimate the typical synchrotron energy as (Zhang & Yan 2011) Ep ≃ 80 keV L 1/2 γ,48R −1 15 η 3/2 x,−2σ 2 4 .”
• PARTICLE ACCELERATION AND PLASMA DYNAMICS DURING MAGNETIC RECONNECTION IN THE MAGNETICALLY DOMINATED REGIME (2015, methodology): “Magnetic reconnection and associated particle acceleration have been proposed as a key process in GRB models such as ICMART model (Zhang & Yan 2011) and reconnection-switch model (McKinney & Uzdensky 2012).”
• MERGERS OF CHARGED BLACK HOLES: GRAVITATIONAL-WAVE EVENTS, SHORT GAMMA-RAY BURSTS, AND FAST RADIO BURSTS (2016, background): “The EM energy is entrained in the outflow and would be dissipated at a large radius through magnetic reconnection triggered by internal collision or current instabilities (Zhang & Yan 2011; Lyutikov & Blandford 2003).”
• Extending the Search for Muon Neutrinos Coincident with Gamma-Ray Bursts in IceCube Data (2017, background): “…tested, the internal shock fireball model (Hümmer et al. 2012; Zhang & Kumar 2013), the photospheric fireball model (Rees & Mészáros 2005; Murase 2008; Zhang & Yan 2011), and the Internal Collision-induced Magnetic Reconnection and Turbulence (ICMART) model (Zhang & Yan 2011; Zhang & Kumar 2013).”
• Relativistic Jets Shine through Shocks or Magnetic Reconnection (2015, background): “…is required, e.g., MHD instabilities at the dissipation radius or large-scalechanges in the magnetic field polarity of the flow (Romanova & Lovelace 1992; Spruit et al. 2001; Drenkhahn & Spruit 2002; Lyutikov 2006; Giannios 2010; Zhang & Yan 2011; McKinney & Uzdensky 2012; Parfrey et al. 2015).”
• A theory of photospheric emission from relativistic, collimated outflows (2012, background): “…has been considered as a way to modify the local comoving photon spectrum (Thompson 1994; Spruit et al. 2001; Rees & Mészáros 2005; Pe’er et al. 2005; Giannios & Spruit 2005; Pe’er et al. 2006; Lazzati et al. 2009; Beloborodov 2010; Ryde et al. 2011; Zhang & Yan 2011; Vurm et al. 2011).”
• DETECTION OF GAMMA-RAY POLARIZATION IN PROMPT EMISSION OF GRB 100826A (2011, background): “…(for reviews, Lazzati 2006; Toma et al. 2009); (a) synchrotron in globally ordered toroidal field (SO model; Granot 2003; Lyutikov et al. 2003; Zhang & Yan 2011), (b) in random fields on plasma skin depth scales (SR model; Granot 2003; Nakar et al. 2003), and (c) in random fields on…”
• Reconnection-driven plasmoids in blazars: fast flares on a slow envelope (2012, background): “The variability patterns of gamma-ray burst (GRB) emission show fast flaring on top of slower-evolving lightcurves that may be connected to such reconnection process (see also Lyutikov 2006; Lazar et al. 2009; McKinney & Uzdensky 2012; Zhang & Yan 2011).”
• A Reconnection Switch to Trigger gamma-Ray Burst Jet Dissipation (2010, background): “Turbulencedriven electromagnetic dissipation from magnetic instabilities induced by internal shocks has also been recently considered (Zhang & Yan 2011), although the conditions for turbulence in highly magnetized jets remain undetermined.”
• The physics of gamma-ray bursts & relativistic jets (2014, background): “Magnetic field reversing directions on short length scales, such as the stripped wind from a fast rotating pulsar, or scrambled field lines that result from repeated internal collisions of ordered, magnetized, outflow [108], are examples where reconnection is expected to take place.”
• Off-axis emission of short γ-ray bursts and the detectability of electromagnetic counterparts of gravitational-wave-detected binary mergers (2016, methodology): “We assume that there are no small-scale relativistic internal motions such as those predicted by turbulencedriven models (Narayan & Kumar 2009) and some magnetic reconnection models (Zhang & Yan 2011).”
• BRIGHT “MERGER-NOVA” FROM THE REMNANT OF A NEUTRON STAR BINARY MERGER: A SIGNATURE OF A NEWLY BORN, MASSIVE, MILLISECOND MAGNETAR (2013, background): “The internal dissipation may arise from turbulent magnetic reconnection due to internal collisions of the magnetar wind (Zhang & Yan 2011) or from the termination shock of the wind (Dai 2004).”
• A COMPREHENSIVE ANALYSIS OF FERMI GAMMA-RAY BURST DATA. I. SPECTRAL COMPONENTS AND THE POSSIBLE PHYSICAL ORIGINS OF LAT/GBM GRBs (2010, background): “…than unity, so that the SSC component is naturally suppressed; (3) A Poynting flux dominated model usually has a larger emission radius than the internal shock model (Lyutikov & Blandford 2003 for current instability and Zhang & Yan 2011 for collisioninduced magnetic reconnection/turbulence).”