Abstract
The baryon cycle of galaxies is a dynamic process involving the intake,
consumption and ejection of vast quantities of gas. In contrast, the
conventional picture of satellite galaxies has them methodically turning a
large gas reservoir into stars until this reservoir is forcibly removed due to
external ram pressure. This picture needs revision. Our modern understanding of
the baryon cycle suggests that in some regimes the simple interruption of the
fresh gas supply may quench satellite galaxies long before stripping events
occur, a process we call overconsumption. We compile measurements from the
literature of observed satellite quenching times at a range of redshifts to
determine if satellites are principally quenched through orbit-based gas
stripping events -- either direct stripping of the disk (ram pressure
stripping) or the extended gas halo (strangulation) -- or from
internally-driven star formation outflows via overconsumption. The observed
timescales show significant deviation from the evolution expected for gas
stripping mechanisms and suggest that either ram pressure stripping is much
more efficient at high redshift, or that secular outflows quench satellites
before orbit-based stripping occurs. Given the strong redshift evolution of
star formation rates, at high redshift (z > 1.5) even moderate outflow rates
will lead to extremely short quenching times with the expectation that such
satellites will be quenched almost immediately following the cessation of
cosmological inflow, regardless of stripping events. Observations of high
redshift satellites give an indirect but sensitive measure of the outflow rate
with current measurements suggesting that outflows are no larger than 2.5 times
the star formation rate for galaxies with a stellar mass of 10^10.5 solar
masses.
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