论文标题
盲人HI和OH吸收线搜索：使用Artip处理MALS和UGMRT的第一个结果
Blind HI and OH absorption line search: first results with MALS and uGMRT processed using ARTIP
论文作者
论文摘要
我们介绍了自动射电望远镜成像管道（ARTIP）的详细信息，以及对HI和OH吸收器的敏感盲目搜索结果，分别为$ z <0.4 $和$ z <0.7 $。 Artip用Python 3.6编写，广泛使用了常见的天文软件应用程序（CASA）工具和任务，旨在使地理分配的Meerkat吸收线调查（MALS）团队可以协作处理大量的无线电侵入量学数据。我们将其应用于使用64-Dish Meerkat射程望远镜和相关器的32K通道模式获得的第一个MALS数据集。仅在目标上只有40分钟，我们提供了最敏感的PKS1830-211频谱，并表征已知的HI（$ z = 0.19 $）和OH（$ Z = 0.89 $）的吸收剂。我们进一步展示了Artip通过将其应用于使用升级的巨型Metrewave射程望远镜（UGMRT）的72个明亮无线电来源的样本中来处理现实观察场景的能力，以盲目地搜索HI和OH吸收剂。我们估计每单位红移的HI和OH吸收剂的数量为$ n_ {21}（z \ sim0.18）<$ 0.14和$ n _ {\ rm oh}（z \ sim0.40）<$ 0.12，分别限制了大型影响$ <$ <$ <$ <$ <$ <$ <$ <$ <$ <$ < 0.022。由于小型红移路径，$Δz\ sim $ 13 hi带有列密度$> 5.4 \ times10^{19} $ cm $ $^{ - 2} $，该调查仅探究了$ρ> 30 $ kpc的星形星系的郊区。具有预期的$Δz\ sim10^{3-4} $的MALS将克服此限制，并在不同环境中在$ 0 <z <1.5 $ $ 0的环境中对星系的冷气体分数提供严格的约束。
We present details of the Automated Radio Telescope Imaging Pipeline (ARTIP) and results of a sensitive blind search for HI and OH absorbers at $z<0.4$ and $z<0.7$, respectively. ARTIP is written in Python 3.6, extensively uses the Common Astronomy Software Application (CASA) tools and tasks, and is designed to enable the geographically-distributed MeerKAT Absorption Line Survey (MALS) team to collaboratively process large volumes of radio interferometric data. We apply it to the first MALS dataset obtained using the 64-dish MeerKAT radio telescope and 32K channel mode of the correlator. With merely 40 minutes on target, we present the most sensitive spectrum of PKS1830-211 ever obtained and characterize the known HI ($z=0.19$) and OH ($z=0.89$) absorbers. We further demonstrate ARTIP's capabilities to handle realistic observing scenarios by applying it to a sample of 72 bright radio sources observed with the upgraded Giant Metrewave Radio Telescope (uGMRT) to blindly search for HI and OH absorbers. We estimate the numbers of HI and OH absorbers per unit redshift to be $n_{21}(z\sim0.18)<$0.14 and $n_{\rm OH}(z\sim0.40)<$0.12, respectively, and constrain the cold gas covering factor of galaxies at large impact parameters (50 kpc $<ρ<$ 150 kpc) to be less than 0.022. Due to the small redshift path, $Δz\sim$13 for HI with column density$>5.4\times10^{19}$ cm$^{-2}$, the survey has probed only the outskirts of star-forming galaxies at $ρ>30$ kpc. MALS with the expected $Δz\sim10^{3-4}$ will overcome this limitation and provide stringent constraints on the cold gas fraction of galaxies in diverse environments over $0<z<1.5$.
