ASTRO
In the literature: open
Mass, metal and energy flow rates through galactic halo gas
In plain words
Gas flows into galaxies to make stars and is pushed out by supernovae and black holes. How much gas, heavy elements and energy cross the halo per year has not been measured directly.
Precise statement
For $L*$ galaxies at $z\sim 0\ \text{to}\ 2$, determine the inflow and outflow rates of mass, metals and energy versus radius in the circumgalactic medium, including the mass-loading factor $\eta=\mathrm{Mdot}_{\mathrm{out}}/\mathrm{SFR}$ and the fraction of metals ever produced that remain in the halo.
What would settle it
Absorption-line kinematics along many sightlines per galaxy combined with emission mapping of halo gas, inverted with flow models that reproduce simulations.