Centaurus A (NGC5128) is a fantastic object, ideal for investigating the characteristics and the role of the gas in an early-type galaxy in the presence of a radio-loud active nucleus. The different phases of the gas - hot (X-ray), warm (ionised) and cold (HI and molecular) - are all detected in this object and can be studied, due to its proximity, at very high spatial resolution. This richness makes Centaurus A truly unique. Spatially, these gas structures span from the pc to the tens of kpc scale. Thus, they allow us to trace very different phenomena, from the formation and evolution of the host galaxy, to the interplay between nuclear activity and ISM and the feeding mechanism of the central black hole. A lot of work has been done to study and understand the characteristics of the gas in this complex object and here I summarise what has been achieved so far.
Spectroastrometry of rotating gas disks for the detection of supermassive black holes in galactic nuclei. II. Application to the galaxy Centaurus A (NGC 5128)
The molecular circumnuclear disk (CND) in Centaurus A: A multi-transition CO and [CI] survey with Herschel, APEX, JCMT, and SEST
我们介绍了赫歇尔空间天文台以及SEST、JCMT和APEX对NGC 128（Centaurus~A）中心致密环核盘的新CO和C^o线测量结果。Cen A中心的CO阶梯与星暴星系或活动星系核的CO阶梯有很大的不同。此外，Cen A [CI]中心发射线的相对强度也比其它星系的强得多。在同一视线范围内，致密的环核盘（CND）的CO表面亮度明显高于伸展得多的薄盘（ETD）。我们的LVG和PDR/XDR模型表明，如果通过紫外光子加热，则大部分CND气体相对较冷（25 - 80 K）且密度不高（~ 300 cm^{-3}），尽管在CND和ETD中都存在一些密度高得多的气体，其密度约为30 000 cm^{-3}。最后，在CND中也有高激发、高密度相（但在ETD中没有），要么是极端PDR的形式，但更可能是XDR的形式。Cen A CND的总气体质量为8.4 x 10^{7} M（太阳），不确定系数为2。CO-H2转换系数为4 x 10^{20} K km/s，也在2倍以内。
A model for the ongoing subcluster interaction in Centaurus
European Southern Observatory（欧洲南方天文台）；Universitätssternwarte der Ludwig-Maximilians Universität（路德维希-马克西米利安大学大学天文台）；INAF – Astronomical Observatory of Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；Departamento de Astronomía, Universidad de Concepción（康塞普西翁大学天文学系）；INAF – Astronomical Observatory of Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；Gran Sasso Science Institute（格兰萨索科学研究所）
