论文标题
一些肮脏的富富富富含污垢：恒星后星系的各种分子气体含量通过吸收粉尘探测
Some Die Filthy Rich: The Diverse Molecular Gas Contents of Post-starburst Galaxies Probed by Dust Absorption
论文作者
论文摘要
猝灭的恒星后星系（QPSB）是一类罕见但重要的星系类别，显示出快速停止或近期恒星形成的迹象。最近的观察结果表明，大约一半的QPSB具有大量的冷气。但是，该分子CO样品太小，并非没有局限性。我们的工作旨在通过应用一种新方法研究统一选择的样本，超过10倍以上，旨在验证先前的结果。特别是，我们介绍了H $α$/h $β$面对面QPSB的详细分析，$ z = 0.02-0.15 $，并使用$ M_ \ star = 10^{10} {10} -10} -10^{11}} \，m_ \ odot $。我们通过应用我们最近的气体质量校准来解释h $α$/h $β$比率，该校准基于非PSB星系，但预测与CO观察$ \ sim 100 $ psbs一致的气体块。我们通过使用具有良好的H $α$/h $β$比率的PSB或通过堆叠光谱测量的PSB来估计分子气体。我们的分析表明，QPSB具有广泛的H $α$/h $β$比率和分子气体分数，与典型的星形或静态星系的气体分数重叠：H $α$/h $α$/h $β\ \ \ 3-8 $和$ f_ \ f_ \ Mathrm {h_2} $ f_ \ mathrm {h_2} \大约4 \％-6 \％$，对应于$ m_ \ mathrm {h_2} \ lot（1-3）\ times 10^{9} {9} \，m_ \ odot $。我们的结果表明，大量的冷气储层仍然存在于大量QPSB中，并且可以说没有被活跃银河系核的反馈去除或破坏。
Quenched post-starburst galaxies (QPSBs) are a rare but important class of galaxies that show signs of rapid cessation or recent rejuvenation of star formation. A recent observation shows that about half of QPSBs have large amounts of cold gas. This molecular CO sample is, however, too small and is not without limitations. Our work aims to verify previous results by applying a new method to study a uniformly selected sample, more than 10 times larger. In particular, we present detailed analysis of H$α$/H$β$ ratios of face-on QPSBs at $z = 0.02 - 0.15$ and with $M_\star = 10^{10}-10^{11}\,M_\odot$. We interpret the H$α$/H$β$ ratios by applying our recent gas mass calibration, which is based on non-PSB galaxies but predicts gas masses that are consistent with CO observations of $\sim 100$ PSBs. We estimate the molecular gas by either using PSBs with well-measured H$α$/H$β$ ratios or by measuring them from stacked spectra. Our analysis reveals that QPSBs have a wide range of H$α$/H$β$ ratios and molecular gas fractions that overlap with the typical gas fractions of star-forming or quiescent galaxies: H$α$/H$β\approx 3-8$ and $f_\mathrm{H_2} \approx 1\%-20\%$ with median $f_\mathrm{H_2} \approx 4\%-6\%$, which correspond to $M_\mathrm{H_2} \approx (1-3) \times 10^{9} \,M_\odot$. Our results indicate that large reservoirs of cold gas are still present in significant numbers of QPSBs, and that they arguably were not removed or destroyed by feedback from active galactic nuclei.
