An algorithm for Monte Carlo time-dependent radiation transfer
Monthly Notices of the Royal Astronomical Society
Oxford University Press (OUP) / Royal Astronomical Society
© 2011 The Author Monthly Notices of the Royal Astronomical Society © 2011 RAS
A new Monte Carlo algorithm for calculating time-dependent radiative transfer under the assumption of local thermodynamic equilibrium is presented. Unlike flux-limited diffusion, the method is polychromatic, includes scattering, and is able to treat the optically-thick and free-streaming regimes simultaneously. The algorithm is tested on a variety of 1D and 2D problems, and good agreement with benchmark solutions is found. The method is used to calculate the time-varying spectral energy distribution from a circumstellar disc illuminated by a protostar whose accretion luminosity is varying. It is shown that the time-lag between the optical variability and the infrared variability results from a combination of the photon traveltime and the thermal response in the disc, and that the lag is an approximately linear function of wavelength.
This research was in part funded by STFC grant number ST/F003277/1.
This is the author accepted manuscript. The final version is available from OUP via the DOI in this record.
Vol. 416 (2), pp. 1500 - 1508