The surprising inefficiency of dwarf satellite quenching
  We study dwarf satellite galaxy quenching using observations from the Geha et
al. (2012) NSA/SDSS catalog together with LCDM cosmological simulations to
facilitate selection and interpretation. We show that fewer than 30% of dwarfs
(M* ~ 10^8.5-10^9.5 Msun) identified as satellites within massive host halos
(Mhost ~ 10^12.5-10^14 Msun) are quenched, in spite of the expectation from
simulations that half of them should have been accreted more than 6 Gyr ago. We
conclude that whatever the action triggering environmental quenching of dwarf
satellites, the process must be highly inefficient. We investigate a series of
simple, one-parameter quenching models in order to understand what is required
to explain the low quenched fraction and conclude that either the quenching
timescale is very long (> 9.5 Gyr, a "slow starvation" scenario) or that the
environmental trigger is not well matched to accretion within the virial
volume. We discuss these results in light of the fact that most of the low mass
dwarf satellites in the Local Group are quenched, a seeming contradiction that
could point to a characteristic mass scale for satellite quenching.
