M51中臂间刺中稠密分子气体的探测
Detection of Dense Molecular Gas in Inter-Arm Spurs in M51
摘要：
旋臂毛刺是在附近星系的消光和8 $μ$ m发射中观察到的突出特征。为了了解它们的分子气体性质，我们使用欧文斯谷射电天文台绘制了M51内部西北旋臂发出的三个支线中的CO（J=1- 0）发射。我们报告CO检测从所有三个支线。分子气体质量和表面密度为M $_{H2} \sim3\times10^6$ M $_{\sun}$和$Σ_{H2} \sim$ 50 M $_{\sun}$ pc $^{-2}$。因此，相对于旋臂而言，突刺是极其弱的特征。然而，由于马刺是垂直于$\sim$ 500 pc的旋臂延伸，并含有足够的恒星形成的燃料，它们可能是观测到的臂间HII区域的诞生地。这减少了对显著时间延迟的要求，否则如果在螺旋臂中开始臂间恒星形成，则需要显著时间延迟。需要类似深度的更大的星系地图，以进一步了解这些马刺的形成和演化以及它们在恒星形成中的作用-这些数据应该会随着新的CARMA和未来的ALMA望远镜而出现，并且可以与最近的几个数值模拟进行比较，这些数值模拟一直在研究螺旋臂马刺的演化。
英文摘要：
Spiral arm spurs are prominent features that have been observed in extinction and 8$μ$m emission in nearby galaxies. In order to understand their molecular gas properties, we used the Owens Valley Radio Observatory to map the CO(J=1--0) emission in three spurs emanating from the inner northwestern spiral arm of M51. We report CO detections from all three spurs. The molecular gas mass and surface density are M$_{H2} \sim3\times10^6$ M$_{\sun}$ and $Σ_{H2} \sim$50 M$_{\sun}$ pc$^{-2}$. Thus, relative to the spiral arms, the spurs are extremely weak features. However, since the spurs are extended perpendicular to the spiral arms for $\sim$500 pc and contain adequate fuel for star formation, they may be the birthplace for observed inter-arm HII regions. This reduces the requirement for the significant time delay that would be otherwise needed if the inter-arm star formation was initiated in the spiral arms. Larger maps of galaxies at similar depth are required to further understand the formation and evolution of these spurs and their role in star formation - such data should be forthcoming with the new CARMA and future ALMA telescopes and can be compared to several recent numerical simulations that have been examining the evolution of spiral arm spurs.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
