High redshift radio galaxies
High redshift radio galaxies
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高红移射电星系
DOI：
10.1117/12.390128
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
R. Fosbury
中科院分区：
文献类型：
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作者：
R. Fosbury
有相当多的证据表明，强大的射电类星体和射电星系是同一个母体群体的方向依赖性表现：包含相应质量黑洞的大质量球状体。在认识到这种统一性之后，研究的目标是阐明活动核及其宿主的结构和组成，以了解我们期望成为最大质量星系的形成和演化。与类星体相反，在类星体中，星系核在光学/近红外波长处的亮度可以超过星系的很大一部分，射电星系包含一个“内置的日冕仪”，使我们无法直接看到星系核。这些天体提供了详细研究宿主星系的最佳机会。特别令人感兴趣的是那些红移大于2的源，它们代表了核活动比现在更常见的时代，并且我们认为这些物体正在组装过程中。与来自太空的高分辨率成像相结合，凯克II的光学偏振光谱法使我们能够清楚地将散射的核辐射与来自宿主星系的恒星和气体发射分开。静止坐标系的紫外发射线光谱表明，在这一时期发生了快速的化学演化. VLT的近红外光谱使我们能够获得静止坐标系光谱中的线和连续谱，从而可以对演化的恒星种群进行调查，并通过测量熟悉的禁止线光谱来扩展成分分析。
There is considerable evidence that powerful radio quasars and radio galaxies are orientation-dependent manifestations of the same parent population: massive spheroids containing correspondingly massive black holes. Following the recognition of this unification, research is directed to the task of elucidating the structure and composition of the active nuclei and their hosts to understand the formation and evolution of what we expect to become the most massive of galaxies. In contrast to the quasars, where the nucleus can outshine the galaxy at optical/near IR wavelengths by a large factor, the radio galaxies contain a 'built-in coronograph' that obscures our direct view to the nucleus. These objects present out best opportunity to study the host galaxy in detail. Of particular interest are those sources with redshifts greater than about 2 that represent an epoch when nuclear activity was much more common that it is now and when we believe these objects were in the process of assembly. In combination with high resolution imaging from space, optical spectropolarimetry with Keck II allows us to clearly separate the scattered nuclear radiation from the stellar and gaseous emission from the host galaxy. The rest- frame UV emission line spectra suggest that rapid chemical evolution is occurring at this epoch. Near IR spectroscopy with the VLT is giving us access to both the lines and continuum in the rest-frame optical spectrum, allowing investigations of the evolved stellar population and extending the composition analysis with measurements of the familiar forbidden-line spectrum.