Measuring Structural Parameters Through Stacking Galaxy Images
  It remains challenging to detect the low surface brightness structures of
faint high-z galaxies, which is key to understanding the structural evolution
of galaxies. The technique of image stacking allows us to measure the averaged
light profile beneath the detection limit and probe the extended structure of a
group of galaxies. We carry out simulations to examine the recovery of the
averaged surface brightness profile through stacking model HST/ACS images of a
set of galaxies as functions of Sersic index (n), effective radius (Re) and
axis ratio (AR). The Sersic profile best fitting the radial profile of the
stacked image is taken as the recovered profile, in comparison with the
intrinsic mean profile of the model galaxies. Our results show that, in
general, the structural parameters of the mean profile can be properly
determined through stacking, although systematic biases need to be corrected
when spreads of Re and AR are counted. We find that Sersic index is slightly
overestimated and Re is underestimated at AR < 0.5 as the stacked image appears
to be more compact due to the presence of inclined galaxies; the spread of Re
biases the stacked profile to have a higher Sersic index. We stress that the
measurements of structural parameters through stacking should take these biases
into account. We estimate the biases in the recovered structural parameters
from stacks of galaxies when the samples have distributions of Re, AR and n
seen in local galaxies.
