A Very Short Guide to PDF/A
Many astronomers in the US community are lucky enough to have support from the National Science Foundation. Such grants require annual progress reports. These reports include, among other information, a list of the "products" of the research over the past year, including (but not limited to) peer-reviewed publications. It is now the case that in addition to listing the publications, they must be deposited in the NSF Public Access Repository (NSF-PAR). There is no exception to this policy for papers that are already freely available, e.g., on the arXiv.
What makes this mandate more challenging is that the paper must be uploaded in a format that few people use: PDF/A. Unlike a normal PDF file, PDF/A are intended as stand-alone documents that are machine readable, with embedded fonts and standardized metadata among other features. This is not a mere suggestion; research.gov will reject your upload if it is not in PDF/A format.
The NSF-recommended way to make a PDF/A is from the Microsoft Word version of your manuscript. Since few if any astronomy papers are written in Word, this method is not useful.
Here are some other options:
(1) Online services such as PDFTron will convert your PDF to PDF/A. The site states that your information will be deleted after 48 hours.
(2) If you have ghostscript installed, running this from the command line should work:
gs -dPDFA -dBATCH -dNOPAUSE -sProcessColorModel=DeviceRGB -sDEVICE=pdfwrite -dPDFACompatibilityPolicy=1 -sOutputFile=output_filename.pdf input_filename.pdf(3) You can make native PDF/A directly from LaTeX using this (extensive) guide (4) Your local librarian may be happy to help you.