论文标题
在禁止的螺旋星系M83中，CO J = 2-1/1-0比率的系统变化
Systematic Variations of CO J=2-1/1-0 Ratio in The Barred Spiral Galaxy M83
论文作者
论文摘要
我们使用来自ALMA的总功率阵列数据介绍了M83中CO J = 2-1/1-0线比的空间变化。尽管这两条线的强度密切相关，但比率在磁盘上有所不同，磁盘的平均比为0.69，显示了银河系中心和两臂螺旋模式。在高分子气体表面密度的区域中，它的高度（> 0.7），但范围从低表面密度区域的低比率。该比率与FUV和IR排放的空间分布和强度很好，FUV是最佳相关性的。它还与IR强度（70/350mic）（灰尘温度的代理）的比率更好，而不是与IR强度相关。综上所述，这些结果表明，即使星际辐射场加热灰尘加热与GMC的状况之间的直接或间接联系，即使对于GMC中的灰尘和块状气体的热耦合而闻名，尽管没有有效的机制。
We present spatial variations of the CO J=2-1/1-0 line ratio in M83 using Total Power array data from ALMA. While the intensities of these two lines correlate tightly, the ratio varies over the disk, with a disk average ratio of 0.69, and shows the galactic center and a two-arm spiral pattern. It is high (>0.7) in regions of high molecular gas surface density, but ranges from low to high ratios in regions of low surface density. The ratio correlates well with the spatial distributions and intensities of FUV and IR emissions, with FUV being the best correlated. It also correlates better with the ratio of IR intensities (70/350mic), a proxy for dust temperature, than with the IR intensities. Taken together, these results suggest either a direct or indirect link between the dust heating by the interstellar radiation field and the condition of GMCs, even though no efficient mechanism is known for a thermal coupling of dust and bulk gas in GMCs.
