A fast, accurate, and robust algorithm for transferring radiation in three-dimensional space

被引:27
作者
Cen, RY [1 ]
机构
[1] Princeton Univ, Princeton Univ Observ, Princeton, NJ 08544 USA
关键词
theory; galaxies : formation; hydrodynamics; large-scale structure of universe; methods : numerical; radiative transfer;
D O I
10.1086/339805
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
A new algorithm for transferring radiation in three-dimensional space is developed. The algorithm computes radiation sources and sinks using the fast Fourier transform method, based on a formulation in which the integral of any quantity ( such as emissivity or opacity) over any volume may be written in the classic convolution form. The algorithm is fast, with the computational time scaling as N (log N)(2) (where N is the number of grid points of a simulation box), independent of the number of radiation sources. Furthermore, in this formulation one can naturally account for both local radiation sources and diffuse background as well as any extra external sources, in a self-consistent fashion. Finally, the algorithm is completely stable and robust. While the algorithm is generally applicable, we test it thoroughly on an encompassing set of problems relevant for cosmological applications. Tests show that computed results with the present algorithm are, in all cases, in very good agreement with analytic expectations, where they exist. For a realistic cosmological density field the algorithm is in excellent agreement with a high-resolution ray-tracing method. Specifically, radiation flux is guaranteed to propagate in the right direction, and its distribution is shown to be computed accurately. The ionization fronts travel at the correct speeds, with errors no larger than about one cell for all the cases tested. The total number of photons is conserved in the worst case at a similar to10% level and typically at a 1%-5% level over hundreds of time steps. As an added advantage, the accuracy of the results depends weakly on the size of the time step, with a typical cosmological hydrodynamic time step being sufficient.
引用
收藏
页码:211 / 227
页数:17
相关论文
共 27 条
[1]   Photon-conserving radiative transfer around point sources in multidimensional numerical cosmology [J].
Abel, T ;
Norman, ML ;
Madau, P .
ASTROPHYSICAL JOURNAL, 1999, 523 (01) :66-71
[2]   Adaptive ray tracing for radiative transfer around point sources [J].
Abel, T ;
Wandelt, BD .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2002, 330 (03) :L53-L56
[3]   Did the universe reionize at redshift six? [J].
Barkana, R .
NEW ASTRONOMY, 2002, 7 (02) :85-100
[4]   In the beginning: the first sources of light and the reionization of the universe [J].
Barkana, R ;
Loeb, A .
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS, 2001, 349 (02) :126-238
[5]   A HIERARCHICAL O(N-LOG-N) FORCE-CALCULATION ALGORITHM [J].
BARNES, J ;
HUT, P .
NATURE, 1986, 324 (6096) :446-449
[6]   Evidence for reionization at z ∼ 6:: Detection of a Gunn-Peterson trough in a z=6.28 quasar [J].
Becker, RH ;
Fan, XH ;
White, RL ;
Strauss, MA ;
Narayanan, VK ;
Lupton, RH ;
Gunn, JE ;
Annis, J ;
Bahcall, NA ;
Brinkmann, J ;
Connolly, AJ ;
Csabai, I ;
Czarapata, PC ;
Doi, M ;
Heckman, TM ;
Hennessy, GS ;
Ivezic, Z ;
Knapp, GR ;
Lamb, DQ ;
McKay, TA ;
Munn, JA ;
Nash, T ;
Nichol, R ;
Pier, JR ;
Richards, GT ;
Schneider, DP ;
Stoughton, C ;
Szalay, AS ;
Thakar, AR ;
York, DG .
ASTRONOMICAL JOURNAL, 2001, 122 (06) :2850-2857
[7]   Revealing the warm-hot intergalactic medium with OVI absorption [J].
Cen, R ;
Tripp, TM ;
Ostriker, JP ;
Jenkins, EB .
ASTROPHYSICAL JOURNAL, 2001, 559 (01) :L5-L8
[8]   COLD DARK-MATTER COSMOLOGY WITH HYDRODYNAMICS AND GALAXY FORMATION - THE EVOLUTION OF THE INTERGALACTIC MEDIUM AND BACKGROUND-RADIATION FIELDS [J].
CEN, RY ;
OSTRIKER, JP .
ASTROPHYSICAL JOURNAL, 1993, 417 (02) :404-414
[9]   GRAVITATIONAL COLLAPSE OF SMALL-SCALE STRUCTURE AS THE ORIGIN OF THE LYMAN-ALPHA FOREST [J].
CEN, RY ;
MIRALDAESCUDE, J ;
OSTRIKER, JP ;
RAUCH, M .
ASTROPHYSICAL JOURNAL, 1994, 437 (01) :L9-L12
[10]   Evolution of the ionizing radiation background and star formation in the aftermath of cosmological reionization [J].
Cen, RY ;
McDonald, P .
ASTROPHYSICAL JOURNAL, 2002, 570 (02) :457-462