论文标题
sgr b2中的云云碰撞？ 3D模拟符合SIO观测值
A cloud-cloud collision in Sgr B2? 3D simulations meet SiO observations
论文作者
论文摘要
我们将SGR B2中冲击气体的性质与从两个分形云之间的碰撞的3D模拟获得的图进行了比较。与$^{13} $ CO（1-0）观测值一致，我们的模拟表明，云云碰撞会产生一个具有高度动荡的密度子结构的区域，平均$ n _ {\ rm H2} \ gtrsim 5 \ times10^{22}}}}}} {22}} \，\ rm cm cm cm cm^{-22} $。 Similarly, our numerical multi-channel shock study shows that colliding clouds are efficient at producing internal shocks with velocities of $5-50\,\rm km\,s^{-1}$ and Mach numbers of $\sim4-40$, which are needed to explain the $\sim 10^{-9}$ SiO abundances inferred from our SiO(2-1) IRAM observations of Sgr B2。总体而言，我们发现SGR B2中的密度结构和震动的气体形态都与$ \ Lessim 0.5 \，\ rm Myr $ -OLD $ -OLD云云碰撞一致。高速冲击是在碰撞的早期阶段产生的，并且可以点燃恒星形成，而在较长的时间尺度上，中度和低速冲击很重要，可以解释SGR B2中的SIO发射。
We compare the properties of shocked gas in Sgr B2 with maps obtained from 3D simulations of a collision between two fractal clouds. In agreement with $^{13}$CO(1-0) observations, our simulations show that a cloud-cloud collision produces a region with a highly turbulent density substructure with an average $N_{\rm H2}\gtrsim 5\times10^{22}\,\rm cm^{-2}$. Similarly, our numerical multi-channel shock study shows that colliding clouds are efficient at producing internal shocks with velocities of $5-50\,\rm km\,s^{-1}$ and Mach numbers of $\sim4-40$, which are needed to explain the $\sim 10^{-9}$ SiO abundances inferred from our SiO(2-1) IRAM observations of Sgr B2. Overall, we find that both the density structure and the shocked gas morphology in Sgr B2 are consistent with a $\lesssim 0.5\,\rm Myr$-old cloud-cloud collision. High-velocity shocks are produced during the early stages of the collision and can ignite star formation, while moderate- and low-velocity shocks are important over longer time-scales and can explain the extended SiO emission in Sgr B2.
