1. ApJ has moved its publishing to IOP and they have slightly changed the formatting. To implement these changes, call emulateapj with the iop option, use

\documentclass[iop]{emulateapj}

Other available options:

[chicago] - (default) typeset as was done in the University of Chicago Press
[twocolumn] - (default) two-column mode
[onecolumn] - main text in one-column mode
[apj]       - typeset as for main journal
[apjl]      - (default) typeset as for ApJ Letters 
[tighten]   - some adjustments to approximate grid typesetting
[numberedappendix]   - number appendix sections as A, B, etc
[appendixfloats]  - use separate numbering for floats within appendix
[twocolappendix]  - make appendix in two-col mode in a two-col paper
[revtex4]   - force using revtex4

2. Starting from version 11/10/2009, emulateapj tries to load revtex4-1 if present on the system. This may cause small changes in typesetting for old documents. If you want full compatibility, please download the last version based on revtex4, emulateapj-rtx4.cls, and bundle it with your TeX source code.

Download emulateapj.cls and use it instead of aastex.cls.

\documentclass{emulateapj}
or
\documentclass[onecolumn]{emulateapj}
(see header for other options)

The user needs to use \documentclass{aastex} and then \usepackage{emulateapj5}.

Some TeX installations (e.g. teTeX) will find all the font files used by apjfonts.sty. If, however, your LaTeX/dvips complains about not finding some fonts, you will have to install them: download apjfonts.tar.gz, unpack and read INSTALL.

If you have any questions, email alexey@head.cfa.harvard.edu