The energy and momentum input of supernova explosions in structured and ionized molecular clouds
The energy and momentum input of supernova explosions in structured and ionized molecular clouds
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DOI：
10.1093/mnras/stv1155
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发表时间：
2014-09
影响因子：
4.8
通讯作者：
S. Walch;T. Naab
中科院分区：
文献类型：
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作者：
S. Walch;T. Naab
我们研究了早期的影响，单一和双超新星（SN）爆炸致密的气体云的三维，高分辨率，流体动力学模拟。研究了云结构、辐射冷却和来自祖星的电离辐射对星际介质净输入动能fkin = Ekin/ESN、热能ftherm = Etherm/ESN和气体动量fP =P/PSN的影响。对于n=100 cm^{-3}的云，动量产生的Sedov和压力驱动的雪犁阶段提前终止（~ 0.01百万年），辐射冷却将耦合限制在f_therm ~ 0.01，f_kin ~ 0.05和f_P ~ 9，明显低于没有冷却的情况。对于预电离云，这些数字仅增加约50%，与云结构无关。这仅足以将约5%的云加速到径向速度> 30 km/s。第二个SN可能会进一步提高耦合效率，如果延迟过去的Sedov阶段的第一次爆炸。这种非常低的耦合效率对许多超新星反馈的星系尺度次分辨率模型产生了怀疑，其中大多数是通过星系性质与观测的定性一致来验证的。电离辐射似乎并没有显着增强SNe与周围气体的直接耦合，因为它将ISM驱动到惰性致密壳层和冷团块中，这是一个在星系尺度模拟中无法解决的过程。我们的研究结果支持以前的结论，即超新星可能只会驱动风，如果一个显着的部分在低密度环境中爆炸，或者如果它们是由电离辐射以外的过程支持。
We investigate the early impact of single and binary supernova (SN) explosions on dense gas clouds with three-dimensional, high-resolution, hydrodynamic simulations. The effect of cloud structure, radiative cooling, and ionising radiation from the progenitor stars on the net input of kinetic energy, f_kin=E_kin/E_SN, thermal energy, f_therm=E_therm/E_SN, and gas momentum f_P=P/P_SN to the interstellar medium (ISM) is tested. For clouds with n=100 cm^{-3}, the momentum generating Sedov and pressure-driven snowplough phases are terminated early (~ 0.01 Myr) and radiative cooling limits the coupling to f_therm ~ 0.01, f_kin ~ 0.05, and f_P ~ 9, significantly lower than for the case without cooling. For pre-ionised clouds these numbers are only increased by ~ 50%, independent of the cloud structure. This only suffices to accelerate ~ 5% of the cloud to radial velocities >30km/s. A second SN might further enhance the coupling efficiencies if delayed past the Sedov phase of the first explosion. Such very low coupling efficiencies cast doubts on many galaxy-scale sub-resolution models for supernova feedback, most of which are validated a posteriori by qualitative agreement of galaxy properties with observations. Ionising radiation appears not to significantly enhance the immediate coupling of SNe to the surrounding gas as it drives the ISM into inert dense shells and cold clumps, a process which is unresolved in galaxy scale simulations. Our results support previous conclusions that supernovae might only drive a wind if a significant fraction explodes in low-density environments or if they are supported by processes other than ionising radiation.