论文标题
Arecibo Galaxy环境调查XII：LEO I组的光学深色HI云
The Arecibo Galaxy Environment Survey XII : Optically dark HI clouds in the Leo I Group
论文作者
论文摘要
使用来自Arecibo Galaxy环境调查的数据，我们报告了在Leo I组中发现的五个HI云，没有检测到光学对应物。在M96和M95之间发现了其中三个云，其中一个是著名的Leo环的东南侧的10 $^{\ prime} $，而第五则相对隔离。 HI Masses范围从2.6 $ \ times $ 10 $^{6} $ - 9.0 $ \ times $ 10 $^{6} $ m $ _ {\ odot} $和速度宽度（W50），从16-42 km/s。尽管潮汐起源是最明显的解释，但这种形成机制面临几个挑战。对于最孤立的云而言，困难是它与相邻星系的距离，并且缺乏这些系统的HI光盘中的任何干扰迹象。对于正常，稳定的星系，一些云层似乎还遵循质量和速度宽度之间的Baryonic Tully-fisher关系，如果它们起源于潮汐，则无法预期。在没有光学对应物的M96和M95之间发现了三个云，但与光学检测到的Galaxy Leg 13具有相似的属性和位置。尽管总体而言，我们赞成潮汐碎片场景来解释云，但我们不能排除原始起源。如果在引起狮子座环的同一事件中产生云
Using data from the Arecibo Galaxy Environment Survey, we report the discovery of five HI clouds in the Leo I group without detected optical counterparts. Three of the clouds are found midway between M96 and M95, one is only 10$^{\prime}$ from the south-east side of the well-known Leo Ring, and the fifth is relatively isolated. HI masses range from 2.6$\times$10$^{6}$ - 9.0$\times$10$^{6}$M$_{\odot}$ and velocity widths (W50) from 16 - 42 km/s. Although a tidal origin is the most obvious explanation, this formation mechanism faces several challenges. For the most isolated cloud, the difficulties are its distance from neighbouring galaxies and the lack of any signs of disturbance in the HI discs of those systems. Some of the clouds also appear to follow the baryonic Tully-Fisher relation between mass and velocity width for normal, stable galaxies which is not expected if they are tidal in origin. Three clouds are found between M96 and M95 which have no optical counterparts, but have otherwise similar properties and location to the optically detected galaxy LeG 13. While overall we favour a tidal debris scenario to explain the clouds, we cannot rule out a primordial origin. If the clouds were produced in the same event that gave rise to the Leo Ring, they may provide important constraints on any model attempting to explain that structure
