Fengshan Liu Oct. 29, in Shanghai

1. Surface Photometry On SDSS images Fengshan Liu Oct. 29, in Shanghai

2. *Outline • SDSS image data & available quantities • Defects in SDSS images & available quantities • Preliminary image reduction • Multi-color surface photometry • Applied to two recent work

9. 1. SDSS image data & available quantities *Available quantities: • Pogson (Pogson 1856) magnitude • PSF magnitude (psfMag) • Filber magnitude (fiberMag) • Petrosian photometry (petroMag) • Model fits (e.g., devMag, expMag, ModelMag) • Shape and Morphology (stars & galaxies) • Radial Profiles

10. *Outline • SDSS image data & available quantities • defects in SDSS images & available quantities • Preliminary image reduction • Multi-color surface photometry • Applied to two recent work

11. 2. Defects in SDSS images & available quantities • Overestimation of sky levels in the vicinity of bright objects (e.g., Strauss et al. 2002; Mandelbaum et al. 2005) • ‘Red halo’ in the PSF wings (e.g., Michard 2002, Wu et al. 2005) • other problems (e.g., red leak to the u filter; cosmic-ray rejection, faint ghosts of saturated stars in z, see SDSS website and Stoughton et al. 2002) • Approximate circular aperture.

14. *Outline • SDSS image data & available quantities • Defects in SDSS images & available quantities • Preliminary image reduction • Multi-color surface photometry • Applied to two recent work

16. *Outline • SDSS image data & available quantities • Defects in SDSS images & available quantities • Preliminary image reduction • Multi-color surface photometry • Applied to two recent work

18. 3. Preliminary image reduction

20. SB ellip pa A3 A4 x0 B3 B4 y0

21. *Outline • SDSS image data & available quantities • Defects in SDSS images & available quantities • Preliminary image reduction • Multi-color surface photometry • Applied to two recent work

22. Work1 Petrosian (Petrosian 1976) parameters profiles (Kjaergaard et al. 1993; Brough et al. 2005) 76 objects : 31 cD-like & 45 ordinary

23. Work2 Mass of SBHs (e.g., Lauer et al. 2006; Batcheldor et al. 2006;Bonta et al. 2006)) ?

24. The End!