High-excitation molecular gas in local luminous AGN hosts
High-excitation molecular gas in local luminous AGN hosts
复制标题
局部发光活动星系核主体中的高激发分子气体
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Pieter Barthel
中科院分区：
文献类型：
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作者：
P. Papadopoulos;Attila Kovacs;A. S. Evans;A. S. Evans;A. S. Evans;Pieter Barthel
目标。在当地宇宙的发光活动星系核主体中发现大量分子气体，为我们利用当前和未来的毫米/亚毫米望远镜详细研究其在星暴和强大活动星系核影响下的物理条件提供了独特的机会。为了实现这一目标，我们提出了对此类天体进行多 J CO 线观测的第一个结果。方法。我们利用詹姆斯·克拉克·麦克斯韦望远镜 (JCMT) 上的毫米/亚毫米接收器对五个本地光学强 AGN 中的 CO J = 3-2、2-1 线以及 3C 293（强大的射电星系）中更高激发的 CO J = 4-3 线进行观测。结果。在所有物体中都发现了发光的 CO J = 3-2 发射和高 CO (3-2)/(1-0) 强度比，表明高度激发的分子气体。在 3C 293 中，鉴于其静止的恒星形成环境和非常低的 AGN X 射线光度，无法轻易解释具有高 CO(4-3)/(1-0) 比率的异常明亮的 CO J = 4-3 线。结论。在3C 293中，强大的喷流与致密的ISM之间众所周知的相互作用所产生的冲击可能是其分子气体在星系范围内高度激发的原因。恒星的形成可以很容易地解释其余天体中的气体激发，尽管高 X 射线 AGN 光度在两种情况下也可以做出重大贡献。局部发光 QSO 主机中 CO（高 J）/（低 J）线比的测量和最终成像可以由部分完成的 ALMA 在调试的早期阶段完成，有望以高线性分辨率对模糊环境中的星暴与活动星系核活动进行敏感探测。
Aims. The discovery of large amounts of molecular gas in the hosts of luminous AGN in the local Universe offers a unique opportunity to study its physical conditions under the influence of starbursts and powerful AGN in great detail with present and future mm/sub-mm telescopes. Towards achieving this goal we present first results of multi-J CO line observations of such objects. Methods. We made use of the mm/sub-mm receivers on the James Clerk Maxwell Telescope (JCMT) to conduct observations of the CO J = 3-2, 2-1 lines in five local, optically powerful AGN and of the higher excitation CO J = 4-3 line in 3C 293 (a powerful radio galaxy). Results. Luminous CO J = 3-2 emission and high CO (3-2)/(1-0) intensity ratios are found in all objects, indicating highly excited molecular gas. In 3C 293, an exceptionally bright CO J = 4-3 line with a high CO(4-3)/(1-0) ratio cannot be easily explained given its quiescent star-forming environment and very low AGN X-ray luminosity. Conclusions. In 3C 293, shocks emanating from a well-known interaction of a powerful jet with a dense ISM may be responsible for the high excitation of its molecular gas on galaxy-wide scales. Star formation can readily account for the gas excitation in the rest of the objects, although high X-ray AGN luminosities can also contribute significantly in two cases. Measuring and eventually imaging CO (high-J)/(low-J) line ratios in local luminous QSO hosts can be done by a partially completed ALMA during its early phases of commissioning, promising a sensitive probe of starburst versus AGN activity in obscured environments at high linear resolutions.