2.5 AE Version 2008-04-29

• We have completed initial development of a work flow for analyzing point sources observed with the EPIC instrument on XMM (§7.1.3). Scientific validation of this work flow has been very limited; observers are encouraged to use this work flow but to closely and skeptically examine the results, particularly background spectra and background scaling. Note that I have almost zero experience with XMM data.

• Our theoretical understanding of how multiple observations of diffuse emission should be combined has improved (§5.14); AE has been revised accordingly.

• Our theoretical understanding of how surface brightness quantities should be calculated from a diffuse extraction has improved (§5.14) and has been implemented in AE.

• Our theoretical understanding of the various ways that background can be handled in diffuse analysis has improved (§7.1.2).

• Our personal recipe for diffuse analysis using an off-target ``sky'' region (§7.1.2) now uses the ``stowed event data'' provided in CALDB to subtract instrumental background, and then simultaneously fits the diffuse and sky net spectra using a shared model for the X-ray background in both regions plus a model for the diffuse emission in one region.

• The AE fitting scripts based on the wabs absorption model have been retired, replaced by scripts based on the tbabs model; the vapec model has replaced the apec model (§5.12).

• Simultaneous instances of the AE FIT_SPECTRA stage can now be run on the same catalog, saving time for observers who wish to fit multiple models and have multiple processors available.