巨大的低表面亮度星系Malin 1：来自GBT/ARGUS观测的分子气体质量的新约束
The giant low surface brightness galaxy Malin 1: new constraints for its molecular gas mass from GBT/ARGUS observations
摘要：
我们报告的结果，从GBT/ARGUS $^{12}$ CO（1-0）的巨大的低表面亮度星系马林1，这使我们能够确定其CO质量的上限，从而其分子气体质量和分子气体质量表面密度$Σ_{H_2}$。虽然我们进行了非常深入的观察，通过17个小时的源积分时间，达到一个噪音水平的$\sim 0.2$ mK（T $^{*}_{A}$）与相应的扩展源CO限制（3 $σ$）的0.09 K km s $^{-1}$，19倍以上的灵敏度比以前的作品，我们没有检测到的$^{12}$ CO（1-0）的发射线。然而，观测使我们能够估计一个上限（3 $σ$）的CO质量约为$7.4 \times 10^9$ M $_\odot$的扩展发射，和$1.4 \times 10^8$ M $_\odot$的中央部分的星系。根据这些图，我们得出结论，分子气体表面密度低于0.3 M $_\odot$ pc $^{-2}$，相应的分子与原子气体质量比低于0.13。这些证据表明，与正常的高表面亮度螺旋相比，马林1星际介质的物理条件完全不同。这，以一种方式到另一种方式，保持一个通常的分子气体示踪剂CO隐藏在我们的观察，尽管不同的恒星和结构性质的马林1观察到的几个作者，因为超过30年。
英文摘要：
We report on results from GBT/ARGUS $^{12}$CO(1-0) observations for the giant low surface brightness galaxy Malin 1, which allow us to determine an upper limit for its CO mass, and hence its molecular gas mass and molecular gas mass surface density $Σ_{H_2}$. Although we performed very deep observations through 17 hours on source integration time, reaching a noise level of $\sim 0.2$ mK (T$^{*}_{A}$) with a corresponding extended source CO limit (3$σ$) of 0.09 K km s$^{-1}$, 19 times more sensitive than previous works, we do not detect the $^{12}$CO(1-0) emission line. However, the observations allow us to estimate an upper limit (3$σ$) for the CO mass of about $7.4 \times 10^9$ M$_\odot$ for the extended emission, and $1.4 \times 10^8$ M$_\odot$ for the central part of the galaxy. With these figures we conclude that the molecular gas surface density is lower than 0.3 M$_\odot$ pc$^{-2}$, and the corresponding molecular to atomic gas mass ratio is lower than 0.13. The evidence suggests a quite different physical conditions for the interstellar medium in Malin 1 compared to that of normal, high surface brightness spirals. This, in one way to another, keeps an usual molecular gas tracer as CO hidden from our observations, in spite of the diverse stellar and structural properties of Malin 1 observed by several authors since more than 30 years.
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。
