论文标题
辐射冷却能量驱动的银河风的特征动量
The Characteristic Momentum of Radiatively Cooling Energy-Driven Galactic Winds
论文作者
论文摘要
超新星的能量注射可能会在快速恒星形成的星系中驱动热超音速银河风，将富含金属的气体驱动到圆形培养基中，并可能加速凉爽的气体。如果充分质量的质量，这种流动在风驱动区域内会变得辐射，从而降低了宿主星系的总体质量流出速率。我们表明，这为热能驱动的风的总流出势头设定了最大值。对于由连续恒星形成驱动的太阳金属性的球形风，$ \ dot p_ \ rm {max} \ simeq 1.9 \ times10^4 \ m_ \ m_ \ odot/\ odot/\ rm {yr \ km/s} \rm{pc})^{0.14}(\dot M_\star/20\ M_\odot/\rm{yr})^{0.86}$, where $α$ is the fraction of supernova energy that thermalizes the wind, and $\dot M_\star$ and $R_\star$ are the star formation rate and radius of the wind-driving 地区。如果热风经历了散装的辐射冷却，或者热风将质量和动量传递到流动的云中，那么热风的最大动量也可以应用于通常在Starburst星系中通常观察到的凉爽电离流出的流出。我们表明，要求热风在大尺度上进行单相冷却，这使总流量动量率最低。这些最大和最小的流出量量具有相似的值，设置了热银河风的特征动量速率，该速率可能会在大尺度上变得辐射。我们发现，大多数光电离流动动量的观察结果都低于理论上的最大值，因此可能是冷却热流的签名。另一方面，许多系统落在散装冷却所需的最小动量以下，这表明观察到的凉爽材料也可能被夹在或与热流中混合在一起。
Energy injection by supernovae may drive hot supersonic galactic winds in rapidly star-forming galaxies, driving metal-enriched gas into the circumgalactic medium and potentially accelerating cool gas. If sufficiently mass-loaded, such flows become radiative within the wind-driving region, reducing the overall mass outflow rate from the host galaxy. We show that this sets a maximum on the total outflow momentum for hot energy-driven winds. For a spherical wind of Solar metallicity driven by continuous star formation, $\dot p_\rm{max} \simeq 1.9\times10^4\ M_\odot/\rm{yr\ km/s}\ (α/0.9)^{0.86}(R_\star/300\ \rm{pc})^{0.14}(\dot M_\star/20\ M_\odot/\rm{yr})^{0.86}$, where $α$ is the fraction of supernova energy that thermalizes the wind, and $\dot M_\star$ and $R_\star$ are the star formation rate and radius of the wind-driving region. This maximum momentum for hot winds can also apply to cool, ionized outflows that are typically observed in starburst galaxies, if the hot wind undergoes bulk radiative cooling or if the hot wind transfers mass and momentum to cool clouds within the flow. We show that requiring the hot wind to undergo single-phase cooling on large scales sets a minimum on the total outflow momentum rate. These maximum and minimum outflow momenta have similar values, setting a characteristic momentum rate of hot galactic winds that can become radiative on large scales. We find that most observations of photoionized outflow wind momentum fall below the theoretical maximum and thus may be signatures of cooling hot flows. On the other hand, many systems fall below the minimum momentum required for bulk cooling, indicating that perhaps the cool material observed has instead been entrained in or mixed with the hot flow.
