Vertical Structure of Neutrino Dominated Accretion Disks and Neutrino Transport in the disks

Abstract

We investigate the vertical structure of neutrino dominated accretion disks by self-consistently considering the detailed microphysics, such as the neutrino transport, vertical hydrostatic equilibrium, the conservation of lepton number, as well as the balance between neutrino cooling, advection cooling and viscosity heating. After obtaining the emitting spectra of neutrinos and antineutrinos by solving the one dimensional Boltzmann equation of neutrino and antineutrino transport in the disk, we calculate the neutrino/antineutrino luminosity and their annihilation luminosity. We find that the total neutrino and antineutrino luminosity is about $10^{54}$ ergs/s and their annihilation luminosity is about $5\times10^{51}$ ergs/s with an extreme accretion rate $10 M_{\rm {sun}}$/s and an alpha viscosity $\alpha=0.1$. In addition, we find that the annihilation luminosity is sensitive to the accretion rate and will not exceed $10^{50}$ ergs/s which is not sufficient to power the most fireball of GRBs, if the accretion rate is lower than $1 M_{\rm {sun}}$/s. Therefore, the effects of the spin of black hole or/and the magnetic field in the accretion flow might be introduced to power the central engine of GRBs.