Systematic Bias in 2MASS Galaxy Photometry
  We report the discovery of a serious bias in galaxy photometry reported in
the 2MASS Extended Source Catalog (Jarrett et al. 2000). Due to an undetermined
flaw in the 2MASS surface photometry routines, isophotal and total magnitudes
calculated by their methods underestimate the luminosity of galaxies from 10%
to 40%. This is found to be due to incorrectly determined scalelengths and
isophotal radii, which are used to define the aperture sizes for Kron and total
fluxes. While 2MASS metric aperture luminosities are correct (and, thus, colors
based on those apertures), comparison to other filters (e.g. optical) based on
total magnitudes will produce erroneous results. We use our own galaxy
photometry package (ARCHANGEL) to determine correct total magnitudes and colors
using the same 2MASS images, but with a more refined surface brightness
reduction scheme. Our resulting colors, and color-magnitude relation, are more
in line with model expectations and previous pointed observations.
