1) Developed UNIX scripts on Shapley and Oort that use DAOPHOT to produce 20-sigma point-source photometry lists for each of the 4 IRAC bands.

• On Oort, the script employs IRAF to run IRAF-DAOPHOT.
• On Shapley the script employs IRAF to convert the initial FITS files to IRAF/imh format and then uses Stetson's stand-alone version of DAOPHOT and Allstar to produce 20-sigma point-source photometry lists for the 4 IRAC band images. It then uses IRAF again to convert the residual images from IRAF/imh format back to FITS files.

2) Developed PSF files for all 4 IRAC bands in both IRAF format and Stetson's DAOPHOT format.

3) Speed tests

• On Shapley, IRAF/DAOPHOT script took 4 minutes to run one exposure (4 IRAC bands, with each image have ~3000 stars)
• On Oort, IRAF/DAOPHOT script took less than 2 minutes.
• The stand-alone Stetson/DAOPHOT script took 5 minutes for the same data set (only runs on Shapley).
• Qualitatively the Stetson version did better on the low level stars and resulted in more uniform residual background. However, we need to quantify the results with more tests. (See bullet #1 of next section).

4) Automated scripts (#1 above) incorporated into OPUS Pipeline.

• When IRAC bands for individual exposures are processed (Level A,B, &C) and placed in the DAOPHOT processing directory, this action triggers OPUS to run DAOPHOT

1) Star list comparisons--need to systematically compare positions and fluxes of test stars with DAOPHOT output.

2) Iterative star finding routine--each pass of DAOPHOT finds stars and removes them from the original image. Determine a criterion for repeating this process until all point sources are found. (currently, the process is hardwired to make two passes).

3) Develop a repeatable routine for determining the PSF. It would be nice to have an automated routine to do this, but if not, at least have a well-developed routine to do this that can easily be reproduced and executed when a confirmation or new PSF is required. (Currently PSF files are manually produced for the 4 IRAC bands from test data.)

4) Develop routines to track information (e.g. which PSF was used) and modify the FITS headers accordingly

5) More testing

• Analyze the effects of diffuse variable background emission on point-source identification and photometry.
• Assess when a source is sufficiently diffuse to exclude from list.
• Research the effect of Malmquist bias. Is the stellar background truly background, or is it the wings of unresolved nearby stars?
• Develop a 5-sigma point source routine; what added problems will this entail? (Currently only a 20-sigma routine exists)
• What corrections/modifications/masks need to be applied to the IRAC images before running DAOPHOT?

6) Error trapping

• What are the fatal errors for DAOPHOT? IRAF?
• What results are spurious? How do we know?