1. Spitzer photometry and more Discussion session goals: Update team & coordinate efforts CLASH in London 20131

2. Elements involved in discussion PSFs in all bands (HST & Spitzer) Robust Spitzer Source Extractor photometry catalogs Quantitative structural parameters CLASH in London 20132

3. Spitzer Mosaics C.f. update on clashwiki for IRAC – Note: MIPS mosaics not yet staged! CLASH in London 20133

4. In situ photometry method Source Extractor – Critical to set detection parameters appropriately, to account for the crowding E.g. a mexican hat, or simply no convolution kernel works well Parameters have been vetted, and new catalogs have been generated – Everything is staged online, and notes are on clashwiki CLASH in London 20134

5. Accounting for crowding Local – Galfit fitting within IRAC mosaics Using high-res information – TFIT (though not using this) – IvoPhot (unresolved-convolution-based) – Python galaxy fitting (pygfit) (uses full resolution structural information) CLASH in London 20135

6. 6

7. pygfit Produces “clean” photometry and uncertainties from crowded low-resolution mosaics Paper submitted to PASP. See http://www.baryons.org/pygfit/ forhttp://www.baryons.org/pygfit/ – paper, – full code including an example, and full simulation suite – cookbook In process of applying it to CLASH – Spitzer PSFs and good IRAC mosaic rms images are critical, testing underway – Need person power! Leonardo+others at STScI? Other CLASH team members? CLASH in London 20137

8. HST PSFs Needed for high-resolution structural fits… Methodology – List of unresolved sources – PSFEx Target & band – Individual FLT files vs mosaics Parallel efforts – Coe – Alberto – Leonardo+ – John – Others? We need to organize all efforts on the archive, systematically! CLASH in London 20138

9. Spitzer PSFs Handbook PSFs – but orientation and AOR details an issue Using the HST-determined unresolved source list – > empirical PSFs for Channel 1 and 2 for all fields Other? PSFEx? Handbook + AOR processed?... C.f. clashwiki update CLASH in London 20139

10. GALAPAGOS/Galfit/dimage status Ulli; goal: HST structure – 1206, F814W – 1206 flanking fields, F814W – 2248, F814W in progress Amata; goal: Subaru structure, calibrate via HST overlap – A383, F814W – 1206, F814W – 0416, F814W Leonardo; goal: needed to have something to test pygfit – MACS 0329, F606W John M, dimage; goal: ICL – 1206, F160W CLASH in London 201310

11. Vetting photometry with SED fitting See quality analysis plots! CLASH in London 201311