A Reconnection Switch to Trigger gamma-Ray Burst Jet Dissipation

By J. McKinney, D. N. B. D. O. Physics, Kavli Institute for Astrophysics, Cosmology, Stanford University, Center for Nonlinear Studies, D. Physics, U. Colorado, Boulder. 2010

224 citations recorded by the source corpus.

Prompt gamma-ray burst (GRB) emission requires some mechanism to dissipate an ultrarelativistic jet. Internal shocks or some form of electromagnetic dissipation are candidate mechanisms. Any mechanism needs to answer basic questions, such as what is the origin of variability, what radius does dissipation occur at, and how does efficient prompt emission occur. These mechanisms also need to be consistent with how ultrarelativistic jets form and stay baryon pure despite turbulence and electromagnetic reconnection near the compact object and despite stellar entrainment within the collapsar model. We use the latest magnetohydrodynamical models of ultrarelativistic jets to explore some of these questions in the context of electromagnetic dissipation due to the slow collisional and fast collisionless reconnection mechanisms, as often associated with Sweet-Parker and Petschek reconnection, respectively. For a highly magnetized ultrarelativistic jet and typical collapsar parameters, we find that significant electromagnetic dissipation may be avoided until it proceeds catastrophically near the jet photosphere at large radii (r {approx} 10{sup 13}-10{sup 14}cm), by which the jet obtains a high Lorentz factor ({gamma} {approx} 100-1000), has a luminosity of L{sub j} {approx} 10{sup 50}-10{sup 51} erg s{sup -1}, has observer variability timescales of order 1s (ranging from 0.001-10s), achieves {gamma}{theta}{sub j} {approx} 10-20more » (for opening half-angle {theta}{sub j}) and so is able to produce jet breaks, and has comparable energy available for both prompt and afterglow emission. A range of model parameters are investigated and simplified scaling laws are derived. This reconnection switch mechanism allows for highly efficient conversion of electromagnetic energy into prompt emission and associates the observed prompt GRB pulse temporal structure with dissipation timescales of some number of reconnecting current sheets embedded in the jet. We hope this work helps motivate the development of self-consistent radiative compressible relativistic reconnection models.« less

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f33634c5cf8d0a30ff99fe5102c76d59d6d553ec

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Citations in the corpus

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).”
The physics of gamma-ray bursts & relativistic jets (2014, background): “Two types of widely discussed central engines satisfy these requirements: a hyper-accreting stellar-mass black hole (Woosley, 1993; Popham et al., 1999; Lee et al., 2000; Narayan et al., 2001; Di Matteo et al., 2002; Wang et al., 2002; McKinney, 2005; Uzdensky and MacFadyen, 2006; Chen and Beloborod”
Relativistic MHD simulations of core-collapse GRB jets: 3D instabilities and magnetic dissipation (2015, background): “…be expected if the magnetic flux threading the jets switches polarity (e.g. Drenkhahn & Spruit 2002; Giannios & Spruit 2005; Narayan et al. 2011; McKinney & Uzdensky 2012; Deng et al. 2015), either due to the oblique magnetic field of a central magnetar producing a striped wind (Metzger et al.…”
Non-thermal particle acceleration in collisionless relativistic electron-proton reconnection (2016, background): “Ghisellini G., Celotti A., Fossati G., Maraschi L., Comastri A., 1998, MNRAS, 301, 451 Giannios D., 2013, MNRAS, 431, 355 Giannios D., Spruit H. C., 2006, A& A, 450, 887 Giannios D., Uzdensky D. A., Begelman M. C., 2009, MNRAS, 395, L29 Giannios D., Uzdensky D. A., Begelman M. C., 2010, MNRAS, 402, ”
Reconnection-driven plasmoids in blazars: fast flares on a slow envelope (2012, background): “The jet contains, instead, small-scale field structures imprinted from the central engine (Romanova & Lovelace 1997, Levinson & van Putten 1997, Giannios 2010, McKinney & Uzdensky 2012).”
General relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around black holes (2012, background): “Higher resolutions, higher Υ, or somewhat thinner disks might promote more persistent jet formation, which is required by some reconnection-based jet models (Uzdensky & McKinney 2011; McKinney & Uzdensky 2012).”
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).”