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For each galaxy we construct a cleaned image
from the original image by
substituting the pixels contaminated by signal from other objects
with the model values from the ellipse fit.
From the cleaned images we determine the following four magnitude quantities

:
the magnitude within the fitted ellipse with
equivalent radius r

:
the magnitude within a circle with radius r
 :
the surface brightness at the fitted ellipse with
equivalent radius r

:
the mean surface brightness within the fitted ellipse
with
equivalent radius r
The intensities in ADU are transformed to magnitudes
using the sky level, the exposure time and an arbitrary zero point of 22.
The surface brightnesses are transformed to
using the CCD scale determined from the astrometry
(Sect. , p. ).
Properties of E and S0 Galaxies in the Clusters HydraI and Coma
Master's Thesis, University of Copenhagen, July 1997
Bo MilvangJensen (milvang@astro.ku.dk)