Testing Galfit

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Testing Galfit. 1 Astronomisches Institut, Ruhr-Uni Bochum 2 Kapteyn Instituut, Rijks-Universiteit Groningen 3 Argelander Institut für Astronomie, Uni Bonn. - PowerPoint PPT Presentation

Text of Testing Galfit

  • Testing GalfitClemens Trachternach1, Olaf Schmithsen1, Gijs Verdoes Klein2, Ewout Helmich2, Dominik Bomans1 ,Ralf-Jrgen Dettmar1, Oliver-Mark Cordes3, Thomas Erben3, Hendrik Hildebrandt3, Patrick Hudelot3, 1Astronomisches Institut, Ruhr-Uni Bochum2Kapteyn Instituut, Rijks-Universiteit Groningen3Argelander Institut fr Astronomie, Uni Bonn

    Calar Alto Colloquium 2005

  • CFHTLSCanada France Hawaii Telescope Legacy Survey36 CCDs1 deg FoV1.2hr exposure time in i-bandMagZP = 25.75 magSeeing 0.95Comparable to the KIDS data

    Calar Alto Colloquium 2005

  • Contaminant correctionGalfit does -minimization at all costsGalfit needs to know that there is a second object (or third, or) to fit it with a new componentNeed 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 fainterObject just outside fitting region but brighter than primary add component

    Calar Alto Colloquium 2005

  • Contaminant correction

    Run 1aRun 1bRun 2aRun 2bDETECT_MINAREA(min. area for 2nd object)30505070MINAREA_PRIMARY100100150150Number of objects35.00025.00025.00020.000Objects fitted113671145372397278Needed time90 h75 h80 h74 h

    Calar Alto Colloquium 2005

  • DETECT_MINAREA (for 2nd object): 30MINAREA_PRIMARY: 100~35000 objects in catalogue~ 11800 objects as primary objects

    Running Galfit with different profiles

    ProfileExpdiskSersicB/D (Sersic+Expdisk)total time / time per obj.(2.6GhZ P4 4GB Ram)39.5 h~ 12 s47 h~ 14.4 s102 h~ 32 s

    Calar Alto Colloquium 2005

  • Galfit got stuck

    Calar Alto Colloquium 2005

  • Galfit got stuckNeed a maximum number of iterationsIf this already exists Check why it didnt stop

    Calar Alto Colloquium 2005