LINER-like Extended Nebulae in ULIRGs: Shocks Generated by Merger-Induced Flows
LINER-like Extended Nebulae in ULIRGs: Shocks Generated by Merger-Induced Flows
复制标题
ULIRG 中的类 LINER 扩展星云：合并诱导流产生的激波
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Instituto de Estructura de la Materia
中科院分区：
文献类型：
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作者：
A. Monreal;S. Arribas;L. C. I. D. A. D. Canarias;A. Potsdam;Space Telescope Science Institut;Instituto de Estructura de la Materia
在这项工作中，我们研究了在六个低z超亮红外星系的样品的二维电离结构的环核和双核区域的积分场光谱。从Veilleux-Osterbrock线比诊断图中得到的这些星系的星系核区（~5-15 kpc）的电离条件是典型的LINER。观测到的谱线比的范围最好解释为存在速度为150-500 km/s的快速激波，而活动星系核或核星暴的电离一般不太可能。在这些星系的星系核区域的二维电离水平和速度色散的比较显示出正相关性，进一步支持的想法，冲击确实是电离的主要原因。这些冲击的起源也进行了研究。尽管在这些系统的环核区域可能存在超级风，但在扩展的环核区域没有发现超级风特征的证据，例如双速度分量。我们考虑了对地震存在的更可能的解释，即合并过程本身引起的潮汐诱导大规模气流的存在，观察到的峰-峰速度为400 km s-1和速度分散的速度场证明了这一点。高达200 km s-1。
In this work we studied the two-dimensional ionization structure of the circumnuclear and extranuclear regions in a sample of six low-z ultraluminous infrared galaxies using integral field spectroscopy. The ionization conditions in the extranuclear regions of these galaxies (~5-15 kpc) are typical of LINERs as obtained from the Veilleux-Osterbrock line ratio diagnostic diagrams. The range of observed line ratios is best explained by the presence of fast shocks with velocities of 150-500 km s-1, while ionization by an AGN or nuclear starburst is in general less likely. The comparison of the two-dimensional ionization level and velocity dispersion in the extranuclear regions of these galaxies shows a positive correlation, further supporting the idea that shocks are indeed the main cause of ionization. The origin of these shocks is also investigated. Despite the likely presence of superwinds in the circumnuclear regions of these systems, no evidence for signatures of superwinds such as double velocity components is found in the extended extranuclear regions. We consider a more likely explanation for the presence of shocks, the existence of tidally induced large-scale gas flows caused by the merging process itself, as evidenced by the observed velocity fields characterized by peak-to-peak velocities of 400 km s-1 and velocity dispersions of up to 200 km s-1.