论文标题
NGC 625中分子云的Alma观察
ALMA Observations of the Molecular Clouds in NGC 625
论文作者
论文摘要
我们提出了最高的分辨率（1英寸）$^{12} $ CO（1-0）观察到矮人Starburst Galaxy NGC 625中分子气的观察结果，该分子是用Alma获得的。分子气体分布在离散云中，在离散云中分布在离散的云中，在$ 0.4 $ kpc $ kpc $^2 $^$^2 $中的总量为n soled scale n oss calscale scale cale scale cale cale cale n oser scale a scale cape n oser scale a的量度均高。 $ 5.3 \ times 10^6 m_ \ odot $，假设我们使用CPROPS套件来识别分子云并测量其属性，则使用CPROPS coper coper co-to-t $ _2 $ _2 $ _2 $ _2。 $ m_ \ odot $ pc $^{ - 2} $。分子气体耗尽时间尺度，均超过$ \ sim 3 $的$ \ sim 3 $，在106-134 MYR的NGC 625中，全球耗尽时间。
We present the highest resolution (1") $^{12}$CO(1-0) observations of molecular gas in the dwarf starburst galaxy NGC 625, to date, obtained with ALMA. Molecular gas is distributed in discrete clouds within an area of $0.4$ kpc$^2$ and does not have well-ordered large-scale motions. We measure a total molecular mass in NGC 625 of $5.3\times 10^6 M_\odot$, assuming a Milky Way CO-to-H$_2$ conversion factor. We use the CPROPS package to identify molecular clouds and measure their properties. The 19 resolved CO clouds have a median radius of 20 pc, a median line width 2.5 km s$^{-1}$, and a median surface density of 169 $M_\odot$pc$^{-2}$. Larson scaling relations suggest that molecular clouds in NGC 625 are mostly in virial equilibrium. Comparison of our high-resolution CO observations with a star formation rate map, inferred from ancillary optical observations observations, suggests that about 40% of the molecular clouds coincide with the brightest HII regions. These bright HII regions have a range of molecular gas depletion timescales, all within a factor of $\sim 3$ of the global depletion time in NGC 625 of 106-134 Myr. The highest surface density molecular clouds towards the southwest of the galaxy, in a region we call the Butterfly, do not show strong star formation activity and suggest a depletion time scale longer than 5 Gyr.
