M51 VLA Observations of HI (1984)

This study contains the data behind a 1990 paper that presented new VLA observations in the 21 cm H I line of the Sc spiral galaxy M51 (NGC 5194) at resolutions ranging from 5 arcsec to 34 arcsec. The H I in the inner regions follows the spiral structure as outlined by the star-forming regions. In the outer parts of the galaxy, faint H I extends to larger radii (up to 21 kpc) and appears to lie in a different plane. From the south, a broad H I tail extends even farther and curves to the north and east, over a projected length of 90 kpc. The velocity structure of the gas in M51 is extremely complicated and difficult to interpret. There seems to be a mixture of effects, such as a possible warp and/or oval distortion, streaming motions along the spiral arms, caused by an (interaction-induced?) density wave, and purely tidal tails and bridges. This paper presents the data in various forms and describes some of the most salient features.

本数据集对应1990年发表的一篇学术论文，该论文公布了针对Sc型螺旋星系M51（NGC 5194）的甚大阵（VLA，Very Large Array）21厘米中性氢（H I）谱线新观测数据，观测分辨率介于5角秒至34角秒之间。星系内部区域的中性氢分布遵循恒星形成区所勾勒出的螺旋结构。在星系外围区域，微弱的中性氢气体延伸至更大半径（最高达21千秒差距（kpc）），且似乎处于与主体不同的平面。从星系南侧延伸出一条宽阔的中性氢尾，其投影长度达90千秒差距，并向北、向东弯曲延展。M51内气体的速度结构极为复杂，难以解读，多种效应相互交织：例如可能存在的星系翘曲和/或椭球形畸变、由（疑似相互作用诱发的）密度波引发的沿旋臂的流运动，以及纯粹的潮汐尾与桥结构。本论文以多种形式呈现了上述观测数据，并阐述了其中部分最为显著的特征。