  While software and algorithms have become increasingly important in
astronomy, the majority of authors who publish computational astronomy research
do not share the source code they develop, making it difficult to replicate and
reuse the work. In this paper we discuss the importance of sharing scientific
source code with the entire astrophysics community, and propose that journals
require authors to make their code publicly available when a paper is
published. That is, we suggest that a paper that involves a computer program
not be accepted for publication unless the source code becomes publicly
available. The adoption of such a policy by editors, editorial boards, and
reviewers will improve the ability to replicate scientific results, and will
also make the computational astronomy methods more available to other
researchers who wish to apply them to their data.
