We present a model of jet precession driven by a neutrino-cooled disk around a spinning black hole to explain the quasi-periodic features observed in some gamma-ray burst light curves. The different orientations of the rotational axes between the outer part of a neutrino-cooled disk and a black hole result in precessions of the central black hole and the inner part of the disk. Hence, the jet arising from the neutrino annihilation above the inner disk is driven to precession. We find that the period of precession is positively correlated with the mass as well as the spin of a black hole.
The vertical structure of neutrino-dominated accretion flows （NDAFs） in spherical coordinates is revisited. We define the ratio of the neutrino cooling rate to the viscous heating rate per unit volume, f=-qJqvis. The ignition region is presented when f〉0.5. The solutions show that NDAF is significantly thick. The ignition region is determined by the mass accretion rate and the vis- cosity parameter, which can be considered as the neutrino radiation-dominated region.
