Image Model Þ Parameters: F, B/T, re, e, fb, n, rd, i, fd, dx, dy, db Notes: (1) Why different position angles for bulge and disk? (2) dx and dy are w. r. t. galaxy centroid! (3) dx and dy are only useful for undersampled images Þ Sersic "bulge" profile: S(r) = Se exp {-b [(r/re)1/n -1]} where b = 1.9992n - 0.3271 Þ Exponential "disk" profile: S(r) = S0 exp(-r/rd) Oversampling ? "Rule of Thumb": Use oversampling when PSF FWHM is less than ~2.5-3 pixels (Nyquist sampling) Background parameter determination Þ dobkg = yes Þ Uses pixels flagged as background by SExtractor Þ Uses mean value for background level Þ Residual background parameter db will be w. r. t. to recomputed level Þ Should db be a free fitting parameter?
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