We construct an analytic phenomenological model for extended warm/hot gaseous coronae of L _ { * } galaxies .
We consider UV OVI COS-Halos absorption line data in combination with Milky Way X-ray OVII and OVIII absorption and emission .
We fit these data with a single model representing the COS-Halos galaxies and a Galactic corona .
Our model is multi-phased , with hot and warm gas components , each with a ( turbulent ) log-normal distribution of temperatures and densities .
The hot gas , traced by the X-ray absorption and emission , is in hydrostatic equilibrium in a Milky Way gravitational potential .
The median temperature of the hot gas is 1.5 \times 10 ^ { 6 } K and the mean hydrogen density is \sim 5 \times 10 ^ { -5 } cm ^ { -3 } .
The warm component as traced by the OVI , is gas that has cooled out of the high density tail of the hot component .
The total warm/hot gas mass is high and is 1.2 \times 10 ^ { 11 } M _ { \odot } .
The gas metallicity we require to reproduce the oxygen ion column densities is 0.5 solar .
The warm OVI component has a short cooling time ( \sim 2 \times 10 ^ { 8 } years ) , as hinted by observations .
The hot component , however , is \sim 80 \% of the total gas mass and is relatively long-lived , with { t _ { cool } } \sim 7 \times 10 ^ { 9 } years .
Our model supports suggestions that hot galactic coronae can contain significant amounts of gas .
These reservoirs may enable galaxies to continue forming stars steadily for long periods of time and account for “ missing baryons ” in galaxies in the local universe .