Deep H I observations of the surroundings of ram pressure stripped Virgo spiral galaxies. Where is the stripped gas
Deep H I observations of the surroundings of ram pressure stripped Virgo spiral galaxies. Where is the stripped gas
复制标题
对冲压压力剥离室女座螺旋星系周围环境的深 H I 观测。
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
H Germany
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文献类型：
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作者：
B. Vollmer;W. H. Cds;O. Strasbourg;F. M. F. Radioastronomie;Bonn;H Germany
介绍了5个缺乏Hi的室女座螺旋星系的深Effelsberg 100米Hi观测。在这些星系中没有发现新的延伸的Hi尾。已知的NGC 4388北部的Hi彗尾并没有比WSRT图像显示的延伸得更远。基于6个室女座螺旋星系样本中Hi尾的缺失，以及之前在目标星系中检测到的面外气体的平衡，我们提出了一个全局图，其中外层气体盘（超过光学半径R 25）被移除的时间比经典ram压力标准预期的要早得多。基于位于星系盘中的氢原子的两相性质，我们认为银河系外盘中温暖的弥漫Hi比冷的致密Hi蒸发得快得多。因此，在撞击压力剥离事件之后，我们只能观察到原子氢，它在被从星系盘移除之前是冷而致密的。这一全球图景与所有现有的观测结果一致。假设初始不亏缺星系，我们检测到剥离质量的0.3%至20%，假设初始Hi亏缺星系，我们检测到剥离质量的3%至70% （$
m def=0.4$）。在后一种假设下，我们用丢失的质量除以从动力学模拟中估计的达到峰值压力的时间来估计蒸发速率。我们发现蒸发速率在10到100 $M_{odot}$ yr -1之间。
Deep Effelsberg 100-m Hi observations of 5 Hi deficient Virgo spiral galaxies are presented. No new extended Hi tail is found in these galaxies. The already known Hi tail north of NGC 4388 does not significantly extend further than a WSRT image has shown. Based on the absence of Hi tails in a sample of 6 Virgo spiral galaxies and a balance of previous detections of extraplanar gas in the targeted galaxies we propose a global picture where the outer gas disk (beyond the optical radius R 25 ) is removed much earlier than expected by the classical ram pressure criterion. Based on the two-phase nature of atomic hydrogen located in a galactic disk, we argue that the warm diffuse Hi in the outer galactic disk is evaporated much more rapidly than the cold dense Hi. Therefore, after a ram pressure stripping event we can only observe atomic hydrogen which was cold and dense before it was removed from the galactic disk. This global picture is consistent with all available observations. We detect between 0.3% and 20% of the stripped mass assuming an initially non-deficient galaxy and between 3% and 70% of the stripped mass assuming an initially Hi deficient galaxy ($
m def=0.4$). Under the latter assumption we estimate an evaporation rate by dividing the missing mass by the estimated time to peak ram pressure from dynamical simulations. We find evaporation rates between 10 and 100 $M_{odot}$ yr -1 .