F..10 October, 2006 (AE Version 3.107)

In the course of extracting a new ACIS observation recently I became annoyed with the complexity of executing my personal AE recipe (recipe.txt, distributed in §7.1). By far the hardest part of the extraction work I'm involved with is fiddling with the catalog prior to the final pass through AE. This is the period where we're noticing missed sources that must be added, identifying invalid sources that we want to remove, and re-positioning sources. Two aspects of this work were particularly awkward: managing the source list (adding, remove, re-positioning sources) and source directories, and generating the various DS9 region files needed at various points in the battle. In this release I've made modest attempts at easing these burdens.

Firstly, I've written a tool to manage the source list and source directories: ae_source_manager (§7.2). Under this paradigm the observer no longer manages lists of source coordinates, manages the AE catalog, or worries about discarding source directories which have become obsolete. Sources are added, removed, and re-positioned via ae_source_manager. The repository of all source information is the AE extraction directories themselves. Observers can attach a PROVENANCE string to each source to help keep track of the method used to detect each source.

Secondly, I've tried to bring some sanity to the generation of DS9 region files that depict the whole catalog by adding a region file generation option to the COLLATE stage (§7.12). Celestial coordinates are used now rather than the silly sky coordinates used previously. Sources now have a LABEL property (managed by ae_source_manager) that is used for labeling DS9 regions. This allows consistent labeling of sources even when region files are generated for sub-sets of the catalog. By default these labels are the sequence number of the source in the catalog, but the observer can supply different labels if desired.

Other changes found in this release are listed below:

• AE now requires TARA version 2006sept4 or later.

• The algorithm used by the tool ae_make_catalog to choose PSF fractions that prevent overlapping extraction regions has been significantly improved. When two sources are in conflict their PSF fractions are adjusted to simultaneously prevent overlap and to exclude approximately the same number of counts from each source. The net effect is that bright sources get larger PSF fractions than weak sources (when necessary). Also, as a side effect of introducing ae_source_manager, the parameters to ae_make_catalog have changed (§7.5).

• The tool ae_better_masking (formerly ae_optimal_masking) has been briefly described in §7.6.3.

• These manual sections have been significantly revised: §3, 7.1, 7.2, 7.12.

• My personal AE usage recipe (recipe.txt, distributed in §7.1) has been significantly revised.

• A list of default parameter values that observers should review has been added to the manual (§7.4).

• The /UPDATE_POSITIONS_DATA and /UPDATE_POSITIONS_CORR stages have been removed from AE.

• The OBS_REGION_FILENAME option has been removed from the EXTRACT_SPECTRA stage.

Note that there is a known bug in CIAO 3.3 that can affect the source masking used to obtain a background event list. Until CIAO is revised you'll probably find that your background data set is cropped somewhat. If this is a concern you can remove the ``update=no'' option to dmcopy in whatever code you're using to mask the sources, e.g. the tools ae_standard_extraction or ae_better_masking, or a manual dmcopy command (§E.5).