学术文献库

The analytic galactic wind model derived by Chevalier and Clegg in 1985 (CC85) assumes $\textit{uniform}$ energy and mass-injection within the starburst galaxy nucleus. However, the structure of nuclear star clusters, bulges, and star-forming knots are non-uniform. We generalize to cases with spherically-symmetric energy/mass injection that scale as $r^{-Δ}$ within the starburst volume $R$, providing solutions for $Δ= 0$, 1/2, 1, 3/2, and 2. In marked contrast with the CC85 model ($Δ=0$), which predicts zero velocity at the center, for a singular isothermal sphere profile ($Δ=2$), we find that the flow maintains a $\textit{constant}$ Mach number of $\mathcal{M}=\sqrt{3/5} \simeq 0.77$ throughout the volume. The fast interior flow can be written as $v_{r < R} = (\dot{E}_T/3\dot{M}_T)^{1/2} \simeq 0.41 \, v_\infty$, where $v_\infty$ is the asymptotic velocity, and $\dot{E}_T$ and $\dot{M}_T$ are the total energy and mass injection rates. For $v_\infty \simeq 2000 \, \mathrm{km \, s^{-1}}$, $v_{r<R} \simeq 820 \, \mathrm{km\, s^{-1}}$ throughout the wind-driving region. The temperature and density profiles of the non-uniform models may be important for interpreting spatially-resolved maps of starburst nuclei. We compute velocity resolved spectra to contrast the $Δ=0$ (CC85) and $Δ=2$ models. Next generation X-ray space telescopes such as XRISM may assess these kinematic predictions.