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arXiv 1202.0236astro-ph.CO
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13个新He II类星体的HST/COS观测

HST/COS Observations of Thirteen New He II Quasars

David Syphers, Scott F. Anderson, Wei Zheng, Avery Meiksin, Donald P. Schneider, Donald G. York

摘要:

星系际氦的完全再电离是IGM历史上的一个重大事件,He II Gunn-Peterson槽的紫外观测使我们能够描述这一过程在z~3处的结束。由于中间的氢吸收,类星体允许这样的研究是罕见的,只有33个已知的文献中,其中大多数是最近发现的。我们扩展了我们以前的发现工作,并提出了13个新的He II类星体,其红移为2.82 < z < 3.77,这里选择的效率约为80%,其中包括几个比以前已知的绝大多数要亮得多的类星体。这是均匀观测到的He II类星体的最大样本,覆盖了如此宽的红移范围,它们显示出IGM不透明度随红移增加的证据,正如氦再电离时期所预期的那样。在单个或平均光谱中没有看到He II Lyα类星体发射的证据,这给宽线区域的标准模型带来了问题。目前的快速进展,在研究He II类星体已经大大促进了宇宙起源光谱仪的HST,我们讨论的仪器和其他微妙的,必须考虑到IGM He II观测。

英文摘要:

The full reionization of intergalactic helium was a major event in the history of the IGM, and UV observations of the He II Gunn-Peterson trough allow us to characterize the end of this process at z~3. Due to intervening hydrogen absorption, quasars allowing such study are rare, with only 33 known in the literature, and most of those are very recent discoveries. We expand on our previous discovery work, and present 13 new He II quasars with redshifts 2.82 < z < 3.77, here selected with ~80% efficiency, and including several that are much brighter than the vast majority of those previously known. This is the largest sample of uniformly observed He II quasars covering such a broad redshift range, and they show evidence of IGM opacity increasing with redshift, as expected for the helium reionization epoch. No evidence of He II Lyα quasar emission is seen in individual or averaged spectra, posing a problem for standard models of the broad line region. The current rapid advance in the study of He II quasars has been greatly facilitated by the Cosmic Origins Spectrograph on HST, and we discuss the instrumental and other subtleties that must be taken into account in IGM He II observations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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