Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-05-05
Astronomy and Astrophysics
Astrophysics
55 pages, 27 figures. ApJ 523 (1999), in press. Corrected equations and text so as to be same as ApJ version
Scientific paper
10.1086/307729
We present analytical approximations for calculating the scattering, absorption and escape of nonionizing photons from a spherically symmetric two-phase clumpy medium, with either a central point source of isotropic radiation, a uniform distribution of isotropic emitters, or uniformly illuminated by external sources. The analytical approximations are based on the mega-grains model of two-phase clumpy media, as proposed by Hobson & Padman, combined with escape and absorption probability formulae for homogeneous media. The accuracy of the approximations is examined by comparison with 3D Monte Carlo simulations of radiative transfer, including multiple scattering. Our studies show that the combined mega-grains and escape/absorption probability formulae provide a good approximation of the escaping and absorbed radiation fractions for a wide range of parameters characterizing the medium. A realistic test is performed by modeling the absorption of a starlike source of radiation by interstellar dust in a clumpy medium, and by calculating the resulting equilibrium dust temperatures and infrared emission spectrum of both the clumps and the interclump medium. In particular, we find that the temperature of dust in clumps is lower than in the interclump medium if clumps are optically thick. Comparison with Monte Carlo simulations of radiative transfer in the same environment shows that the analytic model yields a good approximation of dust temperatures and the emerging UV to FIR spectrum of radiation for all three types of source distributions mentioned above. Our analytical model provides a numerically expedient way to estimate radiative transfer in a variety of interstellar conditions and can be applied to a wide range of astrophysical environments, from star forming regions to starburst galaxies.
Dwek Eli
Varosi Frank
No associations
LandOfFree
Analytical Approximations for Calculating the Escape and Absorption of Radiation in Clumpy Dusty Environments does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Analytical Approximations for Calculating the Escape and Absorption of Radiation in Clumpy Dusty Environments, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Analytical Approximations for Calculating the Escape and Absorption of Radiation in Clumpy Dusty Environments will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-148141