Galaxy And Mass Assembly (GAMA): Environmental Quenching of Centrals and
  Satellites in Groups
  Recently a number of studies have found a similarity between the passive
fraction of central and satellite galaxies when controlled for both stellar and
halo mass. These results suggest that the quenching processes that affect
galaxies are largely agnostic to central/satellite status, which contradicts
the traditional picture of increased satellite quenching via environmental
processes such as stripping, strangulation and starvation. Here we explore this
further using the Galaxy And Mass Assembly (GAMA) survey which extends to ~2dex
lower in stellar mass than SDSS, is more complete for closely-separated
galaxies (>95% compared to >70%), and identifies lower-halo-mass groups outside
of the very local Universe (M$_{\mathrm{halo}}\sim10^{12}$M$_{\odot}$ at
$0.1<z<0.2$). As far as possible we aim to replicate the selections,
completeness corrections and central/satellite division of one of the previous
studies but find clear differences between passive fractions of centrals and
satellites. We also find that our passive fractions increase with both
halo-to-satellite mass ratio and central-to-second rank mass ratio. This
suggests that quenching is more efficient in satellites that are low-mass for
their halo ($i.e$ at high halo-to-satellite mass ratio in comparison to low
halo-to-satellite mass ratio) and are more likely to be passive in older groups
- forming a consistent picture of environmental quenching of satellites. We
then discuss potential explanations for the previously observed similarity,
such as dependence on the group-finding method.
