2006/02/11 by Jun Fukue · 3 citations
Physics and Astronomy · #Accretion (finance) #Astrophysical Phenomena and Observations #Astrophysical jet #Astrophysics and Cosmic Phenomena #Eddington luminosity #Flow (mathematics) #Gamma-ray bursts and supernovae #Radiative transfer #Relativistic beaming #Relativistic particle #Relativistic quantum chemistry #Relativistic speed #astro-ph
paper · pdf · doi:10.1093/pasj/58.2.461
7 pages, 3 figures, PASJ 58 (2006), No 2, in press
arxiv created 2006/02/11 · openalex publication_date 2006/04/25 · arxiv updated 2015/06/24 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We propose a variable Eddington factor, depending on the flow velocity, v, for relativistic radiative flow, whose velocity becomes on the order of the speed of light. When the gaseous flow is radiatively accelerated up to the relativistic regime, the velocity gradient becomes very large in the direction of the flow. As a result, the radiative diffusion may become anisotropic in the comoving frame of the gas. Hence, in a flow that is accelerated from subrelativistic to relativistic regimes, the Eddington factor should be different from 1/3, even in the diffusion limit. As a simple form, the velocity-dependent Eddington factor may be written as f(β) = 1/3 + (2/3) β, where β = v/c. Using the velocity-dependent Eddington factor, we can solve the rigorous equations of the relativistic radiative flow accelerated up to the relativistic speed. We also propose a generalized form for a variable Eddington factor as a function of the optical depth, τ, as well as the flow velocity, f(τ, β) = 1/3 + (2/3) [1+(τ+1)β]/(1+τ+β), for a spherically symmetric case. The velocity-dependent Eddington factor can be used in various relativistic radiatively-driven flows, such as black-hole accretion flows, relativistic astrophysical jets and outflows, and relativistic explosions like gamma-ray bursts.