标题： 空间分辨的星暴和后星暴星系在富集的z~0.55星系团CL0016+16中的光谱学研究 显示英文标题

标题： Spatially Resolved Spectroscopy of Starburst and Post-Starburst Galaxies in The Rich z~0.55 Cluster CL0016+16

摘要： 我们使用W.M.凯克I望远镜上的低分辨率成像光谱仪（LRIS）获得了富星系团CL0016+16中六个后爆发星系和三个尘埃爆发星系的小样本的空间分辨光谱。我们以此测量了Hdelta和OII3727线的径向分布，这些是探测导致这些星系中恒星形成率突然变化机制的诊断探针。在后爆发星系样本中，我们无法检测到Hdelta线等效宽度的径向梯度——尽管有一个星系显示出从星系一侧到另一侧的梯度。这些星系中Hdelta梯度的缺失与它们通过与星系团介质相互作用产生的结果一致，然而，我们的有限空间采样使我们无法得出可靠的结论。样本的所有成员都具有早型形态，这是一般后爆发星系的典型特征，但它们缺乏本地场样本中常见的高频率潮汐尾和扰动。这反驳了合并起源的假设，并加强了星系团介质截断作用的场景。后爆发星系的光谱特征在整个探测的径向范围内是一致的，没有OII3727发射和所有半径处强Hdelta吸收的证据，即后爆发分类不是孔径效应。相反，尘埃爆发星系样本表现出OII3727发射集中在中心的趋势。这最直接地被解释为中心爆发的结果。然而，也存在其他可能性，如非均匀的尘埃分布（这种星系中预期存在）和/或非均匀的爆发年龄分布。样本表现出晚型和不规则形态。 显示英文摘要

摘要： We have used the Low Resolution Imaging Spectrograph (LRIS) on the W.M. Keck I telescope to obtain spatially resolved spectroscopy of a small sample of six post-starburst and three dusty-starburst galaxies in the rich cluster CL0016+16 at z=0.55. We use this to measure radial profiles of the Hdelta and OII3727 lines which are diagnostic probes of the mechanisms that give rise to the abrupt changes in star-formation rates in these galaxies. In the post-starburst sample we are unable to detect any radial gradients in the Hdelta line equivalent width - although one galaxy exhibits a gradient from one side of the galaxy to the other. The absence of Hdelta gradients in these galaxies is consistent with their production via interaction with the intra-cluster medium, however, our limited spatial sampling prevents us from drawing robust conclusions. All members of the sample have early type morphologies, typical of post-starburst galaxies in general, but lack the high incidence of tidal tails and disturbances seen in local field samples. This argues against a merger origin and adds weight to a scenario where truncation by the intra-cluster medium is at work. The post-starburst spectral signature is consistent over the radial extent probed with no evidence of OII3727 emission and strong Hdelta absorption at all radii i.e. the post-starburst classification is not an aperture effect. In contrast the dusty-starburst sample shows a tendency for a central concentration of OII3727 emission. This is most straightforwardly interpreted as the consequence of a central starburst. However, other possibilities exist such as a non-uniform dust distribution (which is expected in such galaxies) and/or a non-uniform starburst age distribution. The sample exhibit late type and irregular morphologies.