论文标题
螺旋臂分子云中的光电离反馈
Photoionising feedback in spiral arm molecular clouds
论文作者
论文摘要
我们介绍了500 pc $^2 $区域的模拟，其中包含质量4 $ \ times $ 10 $^6 $ m $ $ _ \ odot $，从整个螺旋星系模拟中提取，以分辨率扩展，包括来自质量> 18 m $ $ _ $ _ \ odot $的星星的光电电电源。我们的区域进化为10 MYR，并显示沿臂生成$ \ $ 5000群集水槽粒子$ \ $ 5％的簇状星形形成，其中至少包含$ \ $ \ $ 4000星的质量> 18 m $ _ $ _ \ odot $。光电子化对该地区的气体产生了明显的影响，产生了离子腔，并在HII区域的边缘产生了密集的特征。与无反馈案例相比，光电离会产生较大的总云和团块，大约是这样的物体的两倍，它们的单独较小且更加分解。此后，我们看到云的总质量和云的数量迅速减少。与孤立的云的研究不同，我们的模拟遵循电离的远距离影响，而邻近的HII区域从多个方面压缩了一些已经密度的气体。这会导致恒星形成在整个螺旋臂中既加速又部分位移，而在没有反馈的情况下，距离下水道形成部位> 5 pc形成了多达30％的群集水槽颗粒质量。在以后的时间，恒星的形成率降至低于无反馈情况的速度。
We present simulations of a 500 pc$^2$ region, containing gas of mass 4 $\times$ 10$^6$ M$_\odot$, extracted from an entire spiral galaxy simulation, scaled up in resolution, including photoionising feedback from stars of mass > 18 M$_\odot$. Our region is evolved for 10 Myr and shows clustered star formation along the arm generating $\approx$ 5000 cluster sink particles $\approx$ 5% of which contain at least one of the $\approx$ 4000 stars of mass > 18 M$_\odot$. Photoionisation has a noticeable effect on the gas in the region, producing ionised cavities and leading to dense features at the edge of the HII regions. Compared to the no-feedback case, photoionisation produces a larger total mass of clouds and clumps, with around twice as many such objects, which are individually smaller and more broken up. After this we see a rapid decrease in the total mass in clouds and the number of clouds. Unlike studies of isolated clouds, our simulations follow the long range effects of ionisation, with some already-dense gas becoming compressed from multiple sides by neighbouring HII regions. This causes star formation that is both accelerated and partially displaced throughout the spiral arm with up to 30% of our cluster sink particle mass forming at distances > 5 pc from sites of sink formation in the absence of feedback. At later times, the star formation rate decreases to below that of the no-feedback case.
