ALMA CO(3-2) Observations of Star-forming Filaments in a Gas-poor Dwarf Spheroidal Galaxy
ALMA CO(3-2) Observations of Star-forming Filaments in a Gas-poor Dwarf Spheroidal Galaxy
复制标题
ALMA CO(3-2) 贫气矮球状星系中恒星形成细丝的观测
DOI：
10.3847/1538-4357/aa93dc
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Jun
中科院分区：
文献类型：
--
作者：
S. Consiglio;J. Turner;S. Beck;D. Meier;S. Silich;Jun
本文报道了贫气体矮星系NGC 5253中12 CO（3-2）和13 CO（3-2）的阿尔马观测结果。这些0.3（5.5 pc）分辨率的图像显示了小而致密的分子气体云，它们位于运动学上不同的延伸细丝中。一些丝状物似乎正在落入星系，并可能为其当前的星星形成提供燃料。最强烈的CO（3-2）辐射来自中央的100 pc区域，该区域位于被称为超级星云的明亮的无线电红外H ii区域的中心。星暴区内的CO（3-2）团簇与Hα在105 pc尺度上呈反相关，而与射电自由-自由辐射呈良好的相关。围绕着这个超级星云的D1云，有很高的12 CO/13 CO比值，就像在中央100 pc星暴区域的另一个云一样，可能是因为这些云很热。单独的CO（3-2）辐射不能确定云量，因为分子气体温度和柱密度在观测亮度下是简并的，除非与其他谱线（如13 CO）结合。
We report ALMA observations of 12CO(3-2) and 13CO(3-2) in the gas-poor dwarf galaxy NGC 5253. These 0.″3(5.5 pc) resolution images reveal small, dense molecular gas clouds that are located in kinematically distinct extended filaments. Some of the filaments appear to be falling into the galaxy and may be fueling its current star formation. The most intense CO(3–2) emission comes from the central ∼100 pc region centered on the luminous radio-infrared H ii region known as the supernebula. The CO(3–2) clumps within the starburst region are anti-correlated with Hα on ∼5 pc scales, but are well-correlated with radio free–free emission. Cloud D1, which enshrouds the supernebula, has a high 12CO/13CO ratio, as does another cloud within the central 100 pc starburst region, possibly because the clouds are hot. CO(3–2) emission alone does not allow determination of cloud masses as molecular gas temperature and column density are degenerate at the observed brightness, unless combined with other lines such as 13CO.