Discovery of a Group of Star-forming Dwarf Galaxies in A1367
Discovery of a Group of Star-forming Dwarf Galaxies in A1367
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A1367 中一群恒星形成矮星系的发现
DOI：
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发表时间：
2002
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通讯作者：
C. Moss
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作者：
S. Sakai;Robert C. Kennicutt Jr.;J. M. van der Hulst;C. Moss
本文描述了在对A1367星系团进行的大尺度Hα成像巡天中发现的一组活跃的成星矮星系和H II星系的性质。在螺旋星系NGC 3860、CGCG 97-125和CGCG 97-114附近的一个大约150 kpc宽的区域内，发现了大约30个Hα发射节点。后续的成像和光谱学显示，一些结与以前未编目的矮星系（MB = -15.8到-16.5）有关，而其他的则似乎是孤立的H II星系或星系际H II区域。对几个节点的径向速度的测量表明，它们实际上与一个小组或子集群有关，包括CGCG 97-114和CGCG 97-125。迄今为止，在北方的八个阿贝尔星团中，没有发现类似的发射线天体。这些天体中强烈的Hα辐射和它们的高空间密度表明，这不是一组正常的、未受扰动的矮星系。几个节点的发射线光谱也显示，相对于它们的光度，一些节点的金属含量非常丰富。结果表明，这些天体中有许多是由潮汐相互作用或CGCG 97-125和该群其他成员的合并形成或触发的。韦斯特博克合成射电望远镜H I地图显示该地区的潮汐相互作用的直接证据。这些物体可能与在一些相互作用的星系对、合并残余物和致密星系群中发现的潮汐矮星系有关。它们也可能代表了在天炉座星系团中发现的孤立的超紧凑矮星系的进化先驱。
We describe the properties of a remarkable group of actively star-forming dwarf galaxies and H II galaxies in the A1367 cluster, which were discovered in a large-scale Hα imaging survey of the cluster. Approximately 30 Hα-emitting knots were identified in a region approximately 150 kpc across, in the vicinity of the spiral galaxies NGC 3860, CGCG 97-125, and CGCG 97-114. Follow-up imaging and spectroscopy reveal that some of the knots are associated with previously uncataloged dwarf galaxies (MB = -15.8 to -16.5), while others appear to be isolated H II galaxies or intergalactic H II regions. Radial velocities obtained for several of the knots show that they are physically associated with a small group or subcluster, including CGCG 97-114 and CGCG 97-125. No comparable concentration of emission-line objects has been found elsewhere in any of the eight northern Abell clusters surveyed to date. The strong Hα emission in the objects and their high spatial density argue against this being a group of normal, unperturbed dwarf galaxies. Emission-line spectra of several of the knots also show some to be anomalously metal-rich relative to their luminosities. The results suggest that many of these objects were formed or triggered by tidal interactions or mergers involving CGCG 97-125 and other members of the group. A Westerbork Synthesis Radio Telescope H I map of the region shows direct evidence for tidal interactions in the group. These objects may be related to the tidal dwarf galaxies found in some interacting galaxy pairs, merger remnants, and compact groups. They could also represent evolutionary precursors to the class of isolated ultracompact dwarf galaxies that have been identified in the Fornax Cluster.