Begun in 1895 by George E. Hale and James E. Keeler, The Astrophysical Journal is the foremost research journal in the world devoted to recent developments, discoveries, and theories in astronomy and astrophysics. Many of the classic discoveries of the twentieth century have first been reported in the Journal, which has also presented much of the important recent work on quasars, pulsars, neutron stars, black holes, solar and stellar magnetic fields, X-rays, and interstellar matter.
The Letters section was created as Part 2 of The Astrophysical Journal in 1967 by S. Chandrasekhar. He cited the need for a separate publishing schedule that allowed astrophysicists to rapidly publish short notices of their "spectacular developments in astronomy," (S. Chandrasekhar, 1967, ApJ, 148, 1). In 1971, Letters obtained its first editor separate from Part 1.
The Letters is a peer-reviewed express scientific journal. Manuscripts must meet the same criteria for all papers published in The Astrophysical Journal with the additional criteria of timeliness and brevity.
Very long papers (>> 20 pages), papers containing extensive amounts of data or calculations with relatively little analysis or interpretations, or papers of very specialized interest intended for The Astrophysical Journal (Part 1) should be submitted to the Supplement Series. This was created specifically for these types of papers because of the high demand for the limited amount of space in Part 1. Note that a Scientific Editor or referee may also recommend that a paper be published in the Supplement Series. Surveys have shown that papers appearing in the Supplement Series are referenced in the astronomical literature twice as frequently on average as papers in Part 1.
The Astrophysical Journal has a long history of publishing papers on data and instruments that support astronomical observations and theory. Examples of these include papers presenting fundamental data on atomic, molecular, and nuclear astrophysics (theoretical calculations and laboratory experiments), papers on astronomical instrumentation and facilities, papers presenting novel approaches to data analysis and statistical treatment of astronomical data, or papers on relativity, hydrodynamics, plasma theory, particle theory, etc., as applied in astrophysical contexts. The criteria for publishing these papers are similar to those applied generally: the results presented must constitute significant new research that is directly relevant to astrophysical applications. This relevance is best demonstrated if the papers contain examples of astrophysical applications (or in the case of new instruments, example observations). If this is not practical, the relevance of the work to astrophysical problems must be clearly explained and justified. Papers that consist solely of experimental or theoretical results in physics, chemistry, fluid mechanics, relativity, etc., should be submitted to journals that specialize in those subjects.