标题： Coma中最亮的螺旋星系的VLA HI成像 显示英文标题

标题： VLA HI imaging of the brightest spiral galaxies in Coma

摘要： 我们利用VLA的C和D配置获得了后发座星系团中19个螺旋星系的21厘米图像。 样本选择基于星系在阿贝尔半径（1.2度）内的形态、亮度和光学直径。 虽然检测到了氢气但缺乏氢气的星系在它们的氢气属性与到星团中心的投影距离之间显示出强烈的关联。 最强烈缺乏氢气的星系（HI Def > 0.4）位于从后发座星系团中心30角分（约0.6百万秒差距）以内，大致相当于中央X射线发射的范围。 这些中心星系在其氢气分布上显示出明显的不对称性，并且/或者在光学位置和21厘米位置之间存在偏移。 在后发座星系团中观测了七颗所谓的蓝盘星系，并且其中六颗被探测到。 我们对后发座星系团中15个已知后恒星爆发星系中的11个进行了更敏感的氢气搜索。 均未被探测到，典型的氢气质量限制在3到7×10^7太阳质量之间。 我们的结果呈现并增强了对已研究得很好的星团已经熟悉的图景。 缺乏氢气的星系集中在星团的中心。 中央星系的氢气形态，其中光学盘延伸超过氢气盘，在星团环境中是独一无二的，并且强烈表明与IGM的相互作用。 后发座星系团的新结果是气体缺乏的块状分布。 在星团中心，缺乏气体的星系位于东部，而未探测到的星系位于西部。 在外围区域，富含气体的星系位于后发座星系团以北，未检测到的螺旋星系位于东部的NGC 4944群和西南部的NGC 4839群。 这支持了最近的研究发现，即后发座星系团中心正在进行组群合并，进一步向外，NGC 4944和NGC 4839必须已经通过核心，而北部的星系尚未落入。 显示英文摘要

摘要： We have obtained 21cm images of 19 spiral galaxies in the Coma cluster, using the VLA in its C and D configurations. The sample selection was based on morphology, brightness, and optical diameters of galaxies within one Abell radius (1.2 degrees). The HI detected, yet deficient galaxies show a strong correlation in their HI properties with projected distance from the cluster center. The most strongly HI deficient (HI Def > 0.4) galaxies are located inside a radius of 30 arcmin (aprox 0.6 Mpc) from the center of Coma, roughly the extent of the central X-ray emission. These central galaxies show clear asymmetries in their HI distribution and/or shifts between the optical and 21cm positions. Seven so called blue disk galaxies in Coma were observed in HI and six were detected. We did a more sensitive search for HI from 11 of the 15 known post starburst galaxies in Coma. None were detected with typical HI mass limits between 3 and 7x10^7 solar masses. Our results present and enhance a picture already familiar for well studied clusters. HI poor galaxies are concentrated toward the center of the cluster. The HI morphology of the central galaxies, with optical disks extending beyond the HI disks is unique to cluster environments and strongly suggests an interaction with the IGM. A new result in Coma is the clumpy distribution of gas deficiency. In the cluster center the deficient galaxies are to the east while the non-detections are to the west. In the outer parts the gas rich galaxies are north of Coma, non-detected spirals are found in the NGC 4944 group to the east and NGC 4839 group to the SW. This supports recent findings that merging of groups is ongoing in the center of Coma, further out the NGC 4944 and NGC 4839 must have passed through the core, while the galaxies to the north have yet to fall in.