Testing Galfit

1. Testing Galfit 1Astronomisches Institut, Ruhr-Uni Bochum 2Kapteyn Instituut, Rijks-Universiteit Groningen 3Argelander Institut für Astronomie, Uni Bonn Clemens Trachternach1, Olaf Schmithüsen1, Gijs Verdoes Klein2, Ewout Helmich2, Dominik Bomans1 ,Ralf-Jürgen Dettmar1, Oliver-Mark Cordes3, Thomas Erben3, Hendrik Hildebrandt3, Patrick Hudelot3, …

2. CFHTLSCanada France Hawaii Telescope Legacy Survey • 36 CCDs • 1 deg² FoV • 1.2hr exposure time in i-band • MagZP = 25.75 mag • Seeing 0.95’’ • Comparable to the KIDS data Astro-WISE Workshop 2006

3. Contaminant correction • Galfit does χ²-minimization “at all costs“ • Galfit needs to know that there is a second object (or third, or…) to fit it with a new component • Need to think of selection criteria for primary AND secondary objects One possibility (the one I made my tests with): • Object inside fitting region, near primary object and not more than “a few“ magnitudes fainter • Object just outside fitting region but brighter than primary  add component Astro-WISE Workshop 2006

4. Contaminant correction Astro-WISE Workshop 2006

5. Running Galfit with different profiles DETECT_MINAREA (for 2nd object): 30 MINAREA_PRIMARY: 100 ~35000 objects in catalogue ~ 11800 objects as “primary” objects Astro-WISE Workshop 2006

6. Galfit got stuck Astro-WISE Workshop 2006

7. Need a maximum number of iterations If this already exists  Check why it didn’t stop Galfit got stuck Astro-WISE Workshop 2006