论文标题
CO（$ j $ = 1-0）与Alma Morita阵列中Fornax群集中64个星系的映射调查
CO($J$=1-0) mapping survey of 64 galaxies in the Fornax cluster with the ALMA Morita array
论文作者
论文摘要
我们使用Alma Morita阵列在5周期中进行了$^{12} $ C $^{16} $ O（$ j $ = 1-0）（以下简称CO）在Fornax群集中对64个星系进行映射调查。从64个星系中的23个周期中检测到CO排放。我们的样本包括矮人，螺旋和椭圆星系，具有$ M _ {\ rm star} \ sim10^{6.3-11.6} $ m $ 〜m $ $ $ _ \ odot $的恒星质量。在$ \ sim10 $ \ sim10 $ 〜km〜S $^{ - 1} $的速度分辨率下，达到的梁尺寸和灵敏度为$ 15''\ times8'''$和$ \ sim12 $ 〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy''''''$ 〜mjy〜mjy〜mjy〜mjy〜mjy''''''''$ 〜mjy〜mjy〜mjy〜mjy〜mjy〜mjy''''''''''$ 〜mjy〜mjy〜mjy〜mjy〜mjy'''我们研究了38个子样本的冷气（分子和原子气），具有$ m _ {\ rm star}> 10^9 $ 〜m $ $ _ \ odot $与文献hi数据相结合。我们发现：（1）FORNAX星系中的低星形成（SF）活性是由冷气体质量分数减少相对于恒星质量（以下称为气体分数），而不是冷气的SF效率降低。 （2）与SF活性低的星系中的分子气体分子分数相比，原子气分的分数更大。 Fornax星系的冷气特性及其环境特性之间的比较表明，原子质气体被潮汐剥离和通过RAM压力剥离，RAM压力导致分子气体耗尽，借助勒索并因此SF淬灭。组环境中的预处理也将在减少一些Fornax星系中的冷气储层中发挥作用。
We conduct a $^{12}$C$^{16}$O($J$=1-0) (hereafter CO) mapping survey of 64 galaxies in the Fornax cluster using the ALMA Morita array in cycle 5. CO emission is detected from 23 out of the 64 galaxies. Our sample includes dwarf, spiral and elliptical galaxies with stellar masses of $M_{\rm star}\sim10^{6.3-11.6}$~M$_\odot$. The achieved beam size and sensitivity are $15''\times8''$ and $\sim12$~mJy~beam$^{-1}$ at the velocity resolution of $\sim10$~km~s$^{-1}$, respectively. We study the cold-gas (molecular- and atomic-gas) properties of 38 subsamples with $M_{\rm star}>10^9$~M$_\odot$ combined with literature HI data. We find that: (1) the low star-formation (SF) activity in the Fornax galaxies is caused by the decrease in the cold-gas mass fraction with respect to stellar mass (hereafter, gas fraction) rather than the decrease of the SF efficiency from the cold gas; (2) the atomic-gas fraction is more heavily reduced than the molecular-gas fraction of such galaxies with low SF activity. A comparison between the cold-gas properties of the Fornax galaxies and their environmental properties suggests that the atomic gas is stripped tidally and by the ram pressure, which leads to the molecular gas depletion with an aid of the strangulation and consequently SF quenching. Pre-processes in the group environment would also play a role in reducing cold-gas reservoirs in some Fornax galaxies.
