HI in Abell 3128
HI in Abell 3128
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你好，阿贝尔 3128
DOI：
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发表时间：
2001
期刊：
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通讯作者：
M. Wieringa
中科院分区：
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作者：
J. Chengalur;R. Braun;M. Wieringa
我们讨论了澳大利亚望远镜紧凑阵列（ATCA）HI 21厘米数据的星系团A3128。我们的观测故意相对较浅，通过我们的数据立方体进行盲目搜索，只发现了两个星系，其中一个可能是假的。A3128是欧洲南方天文台附近阿贝尔星系团巡天（ENACS）的一部分（Katgert et al. 1996）;在A3128区域有193个星系的红移。其中148个星系的红移使得HI辐射（如果有的话）位于我们的数据立方体内。我们使用这些星系的已知红移coadd它们的光谱，从而提高我们的灵敏度HI发射。该技术是相当成功的（coadded光谱允许检测的平均质量含量为9 - 10 - 8 M，lmost一个数量级低于直接检测（我们的意思是一个5检测后平滑到90 - 00 - 90 - 00和300公里秒-1的分辨率）的个别对象。通过将总星系样本分成子样本，我们发现位于星系团X射线发射核心外的晚型星系的气体含量明显高于核心内的晚型星系。事实上，对于盘星系的平均气体含量是较高的星系外的X射线发射区相比，那些内部意味着这些星系没有很好地混合在集群潜力。即使在X射线发射区之外，富气体星系在星系团中的分布也不均匀，富气体星系集中在星系团的东部。这与早期对A3128中星系运动学的分析是一致的，这表明存在亚星系团。总之，我们发现，coadding光谱是一个强大的工具，在星系团中的HI研究，并建议，这种技术可以应用于大幅增加红移范围内，这样的观测可以进行。
We discuss Australia Telescope Compact Array (ATCA) HI 21 cm data for the galaxy cluster A3128. Our observations are intentionally relatively shallow, and a blind search through our data cube yields (tentative) detections of only two galaxies, of which one is probably spurious. A3128 is part of the ESO Nearby Abell Cluster Survey (ENACS) (Katgert et al. 1996); redshifts are available for 193 galaxies in the A3128 region. For 148 of these galaxies the redshifts are such that the HI emission (if any) would lie within our data cube. We use the known redshifts of these galaxies to coadd their spectra and thus improve our sensitivity to HI emission. The technique is fairly successful { the coadded spectra allow detection of an average mass content of9 10 8 M ,a lmost an order of magnitude lower than for direct detection (by which we mean a 5 detection after smoothing to 90 00 90 00 and 300 km s 1 resolution) of individual objects. By dividing the total galaxy sample into subsamples we nd that the gas content of late type galaxies that lie outside the X-ray emitting core of the cluster is substantially higher than that of those within the core. The fact that for disk galaxies the average gas content is higher for galaxies outside the X-ray emitting region as compared to those inside implies that these galaxies are not well mixed in the cluster potential. Even outside the X-ray emitting region the distribution of gas-rich galaxies in the cluster is not uniform, we nd that gas-rich galaxies are concentrated in the east of the cluster. This is consistent with earlier analyses of the kinematics of the galaxies in A3128 which indicate the presence of subclustering. In summary we nd that coadding spectra is a powerful tool for the study of HI in cluster galaxies, and suggest that this technique could be applied to substantially increase the redshift range over which such observations could be carried out.