2.7 AE Version 2009-01-27

• Our own recipe for using AE (§7.1) has been significantly revised. Our recipe for using AE on XMM data has been simplified to refer to the ACIS recipe when possible.

• The ae_better_backgrounds (§7.14) tool is generally no longer explicitly called by the observer; instead, the tool ae_standard_extraction now has an option /BETTER_BACKGROUNDS which directs it to call ae_better_backgrounds instead of performing the masked background computation.

• AE now supports MARX version 4.3.0. We recommend that you keep your MARX installation up to date in order to have the best possible PSF calibration. Note that the latest MARX has tools in two different directories ({marx_installation_directory}/bin/ and {marx_installation_directory}/lib/marx/), both of which must be in your Unix path.

• AE now requires CIAO version 4.0 or later. AE does not yet work under CIAO version 4.1 (due at least to changes in the structure of CALDB).

• For projects involving multiple observations, we have added several options to the MERGE stage (§7.16) to address the difficult issue of deciding, for each source, when discarding an observation is expected to improve the quality of the merged extraction (§5.13).
  • A limit on the acceptable level of overlap between neighboring extraction regions (§7.2.2) can now be specified via the OVERLAP_LIMIT option .

  • The MERGE_FOR_PB option can optimize the merge for source validity.

  • The MERGE_FOR_POSITION option can optimize the merge for source position.

• AE's grouping algorithm now includes a stronger mechanism to combat the bias that can arise from the asymmetry inherent in the standard grouping algorithm (see 3rd bullet of §5.7).

• The algorithm used by the tool ae_make_catalog to choose PSF fractions that prevent overlapping extraction regions has been significantly improved. CIAOs data model is now used to measure the amount of overlap between neighboring regions; previously we used circular parameterizations of the regions to assess overlap.

• The source position that AE estimates from an image reconstruction of the source neighborhood (RA_ML,DEC_ML) is now a centroid of a 3x3 pixel region in the reconstructed image, rather than the center of the brightest pixel (§7.17).

• When AE calls dmcoords to convert a position to CHIP coordinates, the aspect file is now supplied to dmcoords.

• The EXTRACT_SPECTRA Stage (§7.9) now accepts an observation mask file (via the parameter MSKFILE) for use by mkarf and mkwarf.

• For diffuse sources (§7.1.2), the EXTRACT_SPECTRA Stage (§7.9) now accepts an aspect file (via the parameter ASPECT_FN) for use by mkacisrmf.

• The SHOW_REGIONS stage (§7.8) now requires a FITS collated table rather than a source list.

• The ae_better_backgrounds (§7.14) and ae_better_masking (§7.12.2) tools can now be run on multiple ObsIds at the same time.

• §6.2 describes a number of undocumented AE capabilities that speed up processing for atypical projects.

• The installation section (§6.1) now states a requirement that your shell must not produce any output to stdout when it starts up.

• PSF construction via mkpsf is no longer supported.

• The ae_make_catalog and ae_standard_extraction tools now require the EVTFILE_BASENAME parameter (e.g. EVTFILE_BASENAME='spectral.evt' as shown in §3).

Notes on older AE releases can be found in Appendix D.