论文标题
分子云中的极端紫外线辐射反馈及其对星形簇的质量和大小的影响
Far and extreme UV radiation feedback in molecular clouds and its influence on the mass and size of star clusters
论文作者
论文摘要
我们通过用远紫外线（FUV; $ 6〜 {\ rm ev} \ leqqhν\ leqqhν\ leqq 13.6〜 {\ rm ev} $ {\ rm ev} $）和极端的紫外线（euv; 反馈。我们发现，FUV反馈显着抑制了弥漫性云中的恒星形成，其初始表面密度为$σ_ {\ rm cl} \ sillsim \ sims \ rm 50〜m _ {\ odot} \; PC^{ - 2} $。在有$σ_ {\ rm cl} \ sim \ rm 100-200〜m _ {\ odot} \;的云中。 PC^{-2} $，EUV反馈扮演着主要角色，并降低了小于$ 0.3 $的星形形成效率。我们表明，来自PDR或H {\ sc II}区域的热压会破坏云，并使星形簇的大小更大。因此，带有质量$ m _ {\ rm cl} \ sillsim 10^{5}〜\ rm m _ {\ odot} $的云和表面密度$σ_{\ rm cl} \ sills cl} \ sillssim 200〜 PC^{ - 2} $保留了$ \ sim 100〜 \ rm m _ {\ odot} \; PC^{-3} $以银河系方式非常匹配所观察到的开放群集。如果分子云很大（$ m _ {\ rm cl} \ gtrsim 10^{5}〜\ rm m _ {\ odot} $）和compact（$σ\ gtrsim 400〜 \ gtrsim 400〜 \ rm m _ rm m _ { $ \ sim 10^{4}〜\ rm m _ {\ odot} \; PC^{ - 3} $喜欢观察到的球状簇或年轻的大型星团。因此，我们建议辐射反馈和分子云的初始条件是诱导观察到的星形簇的多样性的关键因素。
We study the formation of star clusters in molecular clouds by performing three-dimensional radiation hydrodynamics simulations with far ultraviolet (FUV; $6 ~{\rm eV} \leqq h ν\leqq 13.6 ~{\rm eV}$) and extreme ultraviolet (EUV; $hν\geqq 13.6~{\rm eV}$) radiative feedback. We find that the FUV feedback significantly suppresses the star formation in diffuse clouds with the initial surface densities of $Σ_{\rm cl} \lesssim \rm 50~M_{\odot} \; pc^{-2}$. In the cases of clouds with $Σ_{\rm cl} \sim \rm 100-200~M_{\odot} \; pc^{-2}$, the EUV feedback plays a main role and decrease the star formation efficiencies less than $0.3$. We show that thermal pressure from PDRs or H{\sc ii} regions disrupts the clouds and makes the size of the star clusters larger. Consequently, the clouds with the mass $M_{\rm cl} \lesssim 10^{5}~\rm M_{\odot}$ and the surface density $Σ_{\rm cl} \lesssim 200~\rm M_{\odot}\; pc^{-2}$ remain the star clusters with the stellar densities of $\sim 100~\rm M_{\odot}\; pc^{-3}$ that nicely match the observed open clusters in the Milky Way. If the molecular clouds are massive ($M_{\rm cl} \gtrsim 10^{5}~\rm M_{\odot}$) and compact ($Σ\gtrsim 400~\rm M_{\odot}\; pc^{-2}$), the radiative feedback is not effective and they form massive dense cluster with the stellar densities of $\sim 10^{4}~\rm M_{\odot}\; pc^{-3}$ like observed globular clusters or young massive star clusters. Thus, we suggest that the radiative feedback and the initial conditions of molecular clouds are key factors inducing the variety of the observed star clusters.
