http://arxiv.org/abs/2210.07193
The galactic wind model of Chevalier1985 (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 inherently non-uniform. We generalize to cases with non-uniform energy/mass injection that scale as $r^{-\Delta}$ within the starburst volume $R$, providing solutions for $\Delta = 0$, 1/2, 1, 3/2, and 2. In marked contrast with the CC85 model ($\Delta=0$), which predicts zero velocity at the center, for a singular isothermal sphere profile ($\Delta=2$), 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 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 CC85 and $\Delta=2$ models. Next generation X-ray space telescopes such as XRISM may assess these kinematic predictions.
D. Nguyen, T. Thompson, E. Schneider, et. al.
Fri, 14 Oct 22
10/75
Comments: submitted (13 October 2022)
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