Relativistic Jets Driven by Antielectron Neutrinos

摘要

The massive accretion disk producing a gamma-ray burst is investigated on the bases of the microphysics of neutrinos and the generalrelativity. The accreting matter is consists of heavy nuclei, free nucleons, degenerated electrons, photons and neutrinos. The fractions of leptons are calculated by using the network of lepton reactions. It is shown that the electron neutrinos are almost trapped in the massive accreting disk with the accretion rate, while the antielectron neutrinos penetrate through the disk and a large quantity of antielectron neutrinos with the large luminosity is ejected from the disk. The fraction of free neutrons per an unit number of baryons, and that of anti-electron neutrinos, increase to be, at the inner disk, while the fractions of free protons and electron neutrinos decrease to be infinitesimal. The cooling by the antielectron neutrinos produces the geometrically thin disk with great density and somewhat low temperature where the scattering optical depth and the degeneracy of the antielectron neutrinos become large. The high mean energy of the antielectron neutrinos and the large luminosity emitted from the accretion disk around a rapidly rotating black hole could drive the out flow, "neutrino driven jets", from the disk.