| profile | An azimuthally-averaged radial
surface brightness profile. In the catalogs, it is given as the
average surface brightness in a series of annuli. This quantity is in
units of maggies per square arcsec. The number of annuli for which there is a
measurable signal is listed as nprof, the mean surface
brightness is listed as profMean, and the error is listed as
profErr. This error includes both photon noise, and the
small-scale "bumpiness" in the counts as a function of azimuthal
angle.
When converting the profMean values to a local surface
brightness, it is not the best approach to assign the mean
surface brightness to some radius within the annulus and then linearly
interpolate between radial bins. Do not use smoothing
splines, as they will not go through the points in the cumulative
profile and thus (obviously) will not conserve flux. What frames pipeline
does, e.g., in determining the Petrosian ratio, is to fit a taut spline to the
cumulative profile and then differentiate that spline fit,
after transforming both the radii and cumulative profiles with asinh
functions. We recommend doing the same here.
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