Douglas F. Watson, Andreas A. Berlind, Andrew R. Zentner
We introduce a new technique that uses galaxy clustering to constrain how
satellite galaxies lose stellar mass and contribute to the diffuse "intrahalo
light" (IHL). We implement two models that relate satellite galaxy stellar mass
loss to the detailed knowledge of subhalo dark matter mass loss. Model 1
assumes that the fractional stellar mass loss of a galaxy is proportional to
the fractional amount of dark matter mass loss of its subhalo. Model 2 accounts
for a delay in the time that stellar mass is lost since the galaxy resides deep
in the potential well of the subhalo which may experience dark matter mass loss
for some time before the galaxy is affected. We use these models to predict the
stellar masses of a population of galaxies and use abundance matching to
predict the clustering of several r-band luminosity threshold samples from the
Sloan Digital Sky Survey. Abundance matching assuming no stellar mass loss
(akin to abundance matching at the time of subhalo infall) over-estimates the
correlation function on small scales (<~ 1 Mpc), while allowing too much
stellar mass loss leads to an under-estimate. For each sample, we are thus able
to constrain the amount of stellar mass loss required to match the observed
clustering. We find that less luminous satellite galaxies experience more
efficient stellar mass loss than luminous satellites. From these models, we can
infer the amount of stellar mass that is deposited into the IHL. We find that
both of our model predictions for the mean amount of IHL as a function of halo
mass are consistent with current observational measurements. However, our two
models predict a different amount of scatter in the IHL from halo to halo, with
Model 2 being favored by observations. This demonstrates that a comparison to
IHL measurements provides independent verification of our stellar mass loss
models. (Abridged)
View original:
http://arxiv.org/abs/1201.2407
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