Quan Guo, Shaun Cole, Vincent Eke, Carlos Frenk
We study the spatial distribution of satellite galaxies around isolated
primaries using the Sloan Digital Sky Survey (SDSS) spectroscopic and
photometric galaxy catalogues. We select isolated primaries from the
spectroscopic sample and search for potential satellites in the much deeper
photometric sample. For specific luminosity primaries we obtain robust
statistical results by stacking as many as ~ 50, 000 galaxy systems. We derive
accurate projected number density profiles of satellites down to 4 magnitudes
fainter than their primaries. We find the normalized satellite profiles
generally have a universal form and can be well fitted by projected NFW
profiles. The NFW concentration parameter increases with decreasing satellite
luminosity while being independent of the luminosity of the primary except for
very bright primaries. The profiles of the faintest satellites show deviations
from the NFW form with an excess at small galactocentric projected distances.
In addition, we quantify how the radial distribution of satellites depends on
the colour of the satellites and the colour and concentration of their
primaries.
View original:
http://arxiv.org/abs/1201.1296
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