Neutrino-dominated Accretion Models for Gamma-Ray Bursts: Effects of General Relativity and Neutrino Opacity

Abstract

We first refine the fixed concept in the literature that the usage of the Newtonian potential in studies of black hole accretion is invalid and the general relativistic effect must be considered. As our main results, we then show that the energy released by neutrino annihilation in neutrino-dominated accretion flows is sufficient for gammaray bursts when the contribution from the optically thick region of the flow is included, and that in the optically thick region advection does not necessarily dominate over neutrino cooling because the advection factor is relevant to the geometrical depth rather than the optical depth of the flow.

Signature of a Newborn Black Hole from the Collapse of a Supra-massive Millisecond Magnetar

“…We also assume a turn-off time of the BH central engine t f , beyond which the tail emission from jet fades as t −(2+β) , where β is the spectral index. The hyper-accreting BH system can launch a relativistic jet via neutrino-antineutrino annihilation (Popham et al 1999;Narayan et al 2001;Di Matteo et al 2002;Gu et al 2006;Chen & Beloborodov 2007;Janiuk et al 2004Janiuk et al , 2007Liu et al 2007Liu et al , 2015Lei et al 2009Lei et al , 2017Xie et al 2016), or Blandford-Znajek mechanism (hereafter BZ; (Blandford & Znajek 1977;Lee et al 2000;Li 2000;Lei et al 2005Lei et al , 2013). The neutrino annihilation mechanism suffers strong baryon loading from the disk and therefore may be too "dirty" to account for a GRB jet Xie et al 2017).…”

Numerical and Analytical Solutions of Neutrino-Dominated Accretion Flows With a Non-Zero Torque Boundary Condition and Its Applications in Gamma-Ray Bursts

“…The NDAF has been extensively investigated and usually compared with the magnetic mechanism (e.g., Narayan et al 2001, hereafter NPK01;Kohri & Mineshige 2002;Di Matteo et al 2002, hereafter DPN02;Chen & Beloborodov 2007;Janiuk et al 2004Janiuk et al , 2007Janiuk et al , 2010Gu et al 2006;Liu et al 2007; Lei et al 2008Lei et al , 2009Lei et al , 2013a. It was for a long time considered as an inefficient model for GRBs.…”

A toy model for magnetized neutrino-dominated accretion flows

“…These models lead to the formation of a transient hot and dense accretion torus/disc around a black hole (BH) of a few solar masses. If an accretion disc is cooled mainly via the neutrino loss, it is referred to as neutrino-dominated accretion flow (NDAF) [1].NDAF has been extensively discussed by many authors [2][3][4][5]. However, the effects of the magnetic fields are usually neglected in NDAF due to the intrinsic complexity.…”

“…NDAF has been extensively discussed by many authors [2][3][4][5]. However, the effects of the magnetic fields are usually neglected in NDAF due to the intrinsic complexity.…”

“…Recently, Chen & Beloborodov [4], Gu et al [5] and Shibata et al [11] argued that the general relativistic (GR) effects are important for NDAF, and we introduce GR correction factors in our model. This paper is organized as follows.…”