Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A 3D radiative transfer framework: V. Homologous Flows   Observations and theoretical calculations have shown the importance of
non-spherically symmetric structures in supernovae. Thus, the interpretation of
observed supernova spectra requires the ability to solve the transfer equation
in 3-D moving atmospheres. We present an implementation of the solution of the
radiative transfer equation in 3-D homologously expanding atmospheres in
spherical coordinates. The implementation is exact to all orders in v/c. We use
a new affine method that makes use of the fact that photons travel on straight
lines. We compare our results in 3-D for spherically symmetric test problems
with high velocity fields and find excellent agreement. Our well-tested 1-D
results are based on methods where the momentum directions vary along the
characteristic (co-moving momentum directions). Thus, we are able to verify
both the analytic framework and its numerical implementation. Additionally, we
have been able to test the parallelization over characteristics. Using 512^2
momentum angles we ran the code on 16,384 Opteron processors and achieved
excellent scaling. It is now possible to calculate synthetic spectra from
realistic 3D hydro simulations. This should open an era of progress in hydro
modeling, similar to that that occurred in the 1980s when 1-D models were
confronted with synthetic spectra.

12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess