E. Obsolete Stages

AE has been evolving and improving for over a decade. As more and more automtion has been added, some AE components are no longer commonly called directly, but are instead called by higher-level tools. For reference, this appendix retains the original description of several AE ``stages'' that now rarely called directly.

E..0.1 Source Lists and Catalogs

The first input parameter to all stages of AE is the name of an ASCII file containing a list of sources that should be processed. Usually this list will include all the sources you're working with, but in some stages it is useful to define subsets of sources that should be processed in different ways, e.g. sets of sources to be fit with different spectral models.

For the first stage (CONSTRUCT_REGIONS) of AE, this file must be a table consisting of 5 whitespace-separated columns specifying the fundamental parameters of each source:

1. source name (e.g. ``182001.09-160717.1''); used to name the Unix directory that will hold the source's data products. A typical source name would be constructed from the coordinates with this IDL expression:
   strcompress(/REMOVE_ALL, adstring( ra, dec, 1, /TRUNCATE))

   Note that when when the ``precision'' parameter to adstring() is zero, standard CXC names of the form ``182001.9-160717'' are built. In crowded fields where those names may not be unique observers may wish to use a precision value of 1 to build names of the form ``181913.56-160129.9''.

2. RA (in degrees); 6 digits to the right of the decimal are recommended.

3. DEC (in degrees); 6 digits to the right of the decimal are recommended.

4. desired PSF fraction ($< 1.0$); controls the relative size of the extraction region.

5. ``primary'' PSF energy, i.e. energy (in keV) at which that PSF fraction is to be computed. A value of 1.5 keV is recommended for most sources since the observed spectrum generally peaks near there, however you are free to choose another energy.

We refer to this 5-column table as a ``catalog''. All other stages of AE require only a list of source names. These stages will accept either a 5-column catalog, or a 1-column list of source names, referred to as a ``source list''. In both catalogs and source lists, lines starting with a semicolon are interpreted as comments. Here's an example of the format of a catalog:

; Comments start with semicolon.
181913.56-160129.9 274.806530 -16.024992 0.90 1.4967
181913.69-160110.5 274.807070 -16.019584 0.90 1.4967
; Comments can be anywhere.
181914.42-161234.6 274.810120 -16.209638 0.90 1.4967
181922.01-160314.9 274.841730 -16.054165 0.90 1.4967