Constant-inflow gas regulator solution
= Constant-inflow gas regulator solution
With constant inflow $\Phi$, no <mass> return or outflow, and $\Psi=\epsilon M_g$, <mass> conservation gives $M_g=\Phi/\epsilon+(M_0-\Phi/\epsilon)e^{-\epsilon t}$. Positive $\epsilon$ makes the <gas> equilibrium stable, with perturbations decaying on timescale $\epsilon^{-1}$. The <star formation rate> tends to the inflow, not necessarily to zero.