Artículo de revista
Benchmarking the calculation of stochastic heating and emissivity of dust grains in the context of radiative transfer simulations
Fecha
2015Registro en:
A&A 580, A87 (2015)
DOI: 10.1051/0004-6361/201525998
Autor
Camps, Peter
Misselt, Karl
Bianchi, Simone
Lunttila, Tuomas
Pinte, Christophe
Natale, Giovanni
Juvela, Mika
Fischera, Joerg
Fitzgerald, Michael P.
Gordon, Karl
Baes, Maarten
Steinacker, Jürgen
Institución
Resumen
Context. Thermal emission by stochastically heated dust grains (SHGs) plays an important role in the radiative transfer (RT) problem
for a dusty medium. It is therefore essential to verify that RT codes properly calculate the dust emission before studying the e ffects of
spatial distribution and other model parameters on the simulated observables.
Aims. We define an appropriate problem for benchmarking dust emissivity calculations in the context of RT simulations, specifically
including the emission from SHGs. Our aim is to provide a self-contained guide for implementors of such functionality and to
off er insight into the e ffects of the various approximations and heuristics implemented by the participating codes to accelerate the
calculations.
Methods. The benchmark problem definition includes the optical and calorimetric material properties and the grain size distributions
for a typical astronomical dust mixture with silicate, graphite, and PAH components. It also includes a series of analytically defined
radiation fields to which the dust population is to be exposed and instructions for the desired output. We processed this problem
using six RT codes participating in this benchmark e ffort and compared the results to a reference solution computed with the publicly
available dust emission code DustEM.
Results. The participating codes implement di erent heuristics to keep the calculation time at an acceptable level.We study the e ects
of these mechanisms on the calculated solutions and report on the level of (dis)agreement between the participating codes. For all but
the most extreme input fields, we find agreement within 10% across the important wavelength range 3 m 1000 m.
Conclusions. We conclude that the relevant modules in RT codes can and do produce fairly consistent results for the emissivity
spectra of SHGs. This work can serve as a reference for implementors of dust RT codes, and it will pave the way for a more extensive
benchmark e ffort focusing on the RT aspects of the various codes.