SIMBAD references

The structure of relativistic radiation mediated shocks (RRMSs) propagating into a cold electron-proton plasma is calculated and analyzed. A qualitative discussion of the physics of relativistic and non-relativistic shocks, including order of magnitude estimates for the relevant temperature and length scales, is presented. Detailed numerical solutions are derived for shock Lorentz factors Γ_u in the range 6 ≤ Γ_u≤ 30, using a novel iteration technique solving the hydrodynamics and radiation transport equations (the protons, electrons, and positrons are argued to be coupled by collective plasma processes and are treated as a fluid). The shock transition (deceleration) region, where the Lorentz factor Γ drops from Γ_u to ∼1, is characterized by high plasma temperatures T ∼ Γm_e c ² and highly anisotropic radiation, with characteristic shock-frame energy of upstream (US) and downstream (DS) going photons of a fewxm_e c ² and ~Γ² m_e c ², respectively. Photon scattering is dominated by e ^± pairs, with the pair-to-proton density ratio reaching ~10²Γ_u. The width of the deceleration region, in terms of Thomson optical depths for US-going photons, is large, Δτ ∼ Γ²_u(Δτ ∼ 1 neglecting the contribution of pairs) due to Klein-Nishina suppression of the scattering cross section. A high-energy photon component, narrowly beamed in the DS direction, with a nearly flat power-law-like spectrum, νI _ν∝ ν⁰, and an energy cutoff at ~Γ²_um_ec ² carries a fair fraction of the energy flux at the end of the deceleration region. An approximate analytic model of RRMS, reproducing the main features of the numerical results, is provided.