Jet precession driven by neutrino-cooled disk for gamma-ray bursts

Abstract

Aims.A model of jet precession driven by a neutrino-cooled disk around a spinning black hole is presented to explain the temporal structure and spectral evolution of gamma-ray bursts (GRBs). Methods. The differential rotation of the outer part of a neutrino-dominated accretion disk may result in precession of the inner part of the disk and the central black hole, hence driving a precessed jet via neutrino annihilation around the inner part of the disk. Results. Both analytic and numeric results for our model are presented. Our calculations show that a black-hole, accretion-disk system with the black hole mass M 3.66 M , accretion rateṀ 0.54 M s −1 , spin parameter a = 0.9, and viscosity parameter α = 0.01 may drive a precessed jet with period P = 1 s and luminosity L = 10 51 erg s −1 , corresponding to the scenario for long GRBs. A precessed jet with P = 0.1 s and L = 10 50 erg s −1 may be powered by a system with M 5.59 M ,Ṁ 0.74 M s −1 , a = 0.1, and α = 0.01, and is possibly responsible for the short GRBs. Both the temporal and spectral evolution in GRB pulse may be explained with our model. Conclusions. GRB central engines most likely power a precessed jet driven by a neutrino-cooled disk. The global GRB lightcurves thus could be modulated by the jet precession during the accretion timescale of the GRB central engine. Both the temporal and spectral evolution in GRB pulse may stem from a viewing effect of the jet precession.

A COMPREHENSIVE ANALYSIS OFFERMIGAMMA-RAY BURST DATA. II.EpEVOLUTION PATTERNS AND IMPLICATIONS FOR THE OBSERVED SPECTRUM-LUMINOSITY RELATIONS

“…It has been proposed that broad pulses with a dramatic E p evolution in GRBs may be due to the precession of GRB jets (Portegies Zwart et al 1999;Reynoso et al 2006;Lei et al 2007;Liu et al 2010). Fixing the observer's viewing angle, the precession would then result in the jet sweeping in and out of the observer's line of sight.…”

“…Since both E p and luminosity are positively related to the Doppler factor, this model could explain the intensity-tracking behavior of the pulses. Since there is no preference for the direction of the precession, the pulse tends to be symmetric (Liu et al 2010).…”

“…Currently favored jet-launching models for GRBs include the neutrino-annihilation mechanism (Popham et al 1999) and the Blandford-Znajek process (Blandford & Znajek 1977). For both models, the jet is expected to be perpendicular to the midplane of the disk, so that the precession of the disk would result in the precession of the jet (Lei et al 2007;Liu et al 2010). It is found that the overall shape and temporal evolution of GRB light curves can be fit with jet procession if the jet is narrow enough (Lei et al 2007;Liu et al 2010).…”

Comparison of Gravitational Waves from Central Engines of Gamma-Ray Bursts: Neutrino-dominated Accretion Flows, Blandford–Znajek Mechanisms, and Millisecond Magnetars

“…Liu et al (2010) investigated that the jet precession driven by an NDAF around a spinning BH. The outer disk forces the BH to precess while the inner disk is aligned with the BH spin axis.…”

The Tidal Disruption of Stars by Supermassive Black Holes

“…Others have considered an inclined disk 235 CHAPTER 7. DISK PRECESSION IN SGRBS whose inner regions include a Bardeen-Petterson warp; in their model the inner region of a neutrino-dominated accretion flow (NDAF) precesses along with the BH spin about the total angular momentum vector (Liu et al 2010). …”