论文标题
巨大银河流出期间的银乳糖形成和气体降水
Galactopause Formation and Gas Precipitation During Strong Galactic Outflows
论文作者
论文摘要
我们使用X射线限制的β模型来用于星系郊区气体的径向分布，我们分析了银河风的终止以及通过热不稳定性的晕光云的形成和演化。以低质量降低速率，银河风被捕获在光环中，但在与（DM/DT）_W> 10 m_sun/yr的间歇性强外流期间，它们在间歇性强的外流中突然爆裂。我们开发了光晕云的分析模型，因为它们在凝结时间辐射冷却时缩放t_c =（390 myr）（t_6 /n _ { - 4}）（z /z_sun）^-1，对于氢数密度N_H =（10^{ - 4} cm^{ - 4} cm^{ - 3} cm^{ - 3}）金属（z/z_sun）。光晕气可以形成KPC尺度的云到半乳酸距离r = 30-65 kpc，其中有效的辐射冷却从10^6 k下降到10^4 k，在z> 0.3 z_sun上发生在小于1 Gyr的时间尺度上。凝结至色谱柱密度N_H> 3.5x10^{16} cm^{ - 2}后，这些云会失去静水压力支持，并在200 Myr的动态时间尺度上向内落下。我们的基线分析将进行数值计算，以了解光环云形成和气体传输到银河磁盘的管理原理。
Using X-ray constrained beta-models for the radial distribution of gas in the outskirts of galaxies, we analyze the termination of galactic winds and the formation and evolution of halo clouds by thermal instability. At low mass-loss rates, galactic winds are trapped within the halo, but they burst into the intergalactic medium during intermittent strong outflows with (dM/dt)_w > 10 M_sun/yr. We develop analytic models of halo clouds as they cool radiatively over condensation time scales t_c = (390 Myr)(T_6 /n_{-4}) (Z/Z_sun)^-1 for hydrogen number densities n_H = (10^{-4} cm^{-3}) n_{-4}, gas temperatures T = (10^6 K)T_6, and metallicities (Z/Z_sun). Halo gas can form kpc-scale clouds out to galactocentric distances r = 30-65 kpc, where efficient radiative cooling from 10^6 K down to 10^4 K occurs at Z > 0.3 Z_sun on timescales less than 1 Gyr. After condensing to column densities N_H > 3.5x10^{16} cm^{-2}, these clouds lose hydrostatic pressure support and fall inward on dynamical time scales of 200 Myr. Our baseline analysis will be followed by numerical calculations to understand the governing principles of halo cloud formation and transport of gas to the galactic disk.
