Redshift Differences between the Balmer and [O III] λ5007 Lines in High-Redshift Quasars
Redshift Differences between the Balmer and [O III] λ5007 Lines in High-Redshift Quasars
复制标题
高红移类星体中巴尔默线和 [O III] λ5007 线之间的红移差异
DOI：
10.1086/310906
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
M. Iye
中科院分区：
文献类型：
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作者：
E. Nishihara;T. Yamashita;Michitoshi Yoshida;E. Watanabe;S. Okumura;A. Mori;M. Iye
我们展示了 z≃1.5 处的四个类星体 (QSO) 的近红外光谱，其中包含红移的 Hα、Hβ 和 [O III] 发射线。这些天体中的 Hα 剖面相对于 [O III] λ5007 导出的系统速度平均红移 430±170 km s−1。这比低红移天体测得的巴尔默线速度偏移要大得多，并且与红移差异随着连续光度增加而增加的趋势一致。这些物体中的静止框架紫外线显示出相对于系统速度的大的（~1000 km s-1）蓝移，因此Hα的大红移与这些红移差异对电离势的依赖性是一致的。这些结果还表明，非常明亮的 QSO 的系统速度只能从窄发射线精确测量。
We present near-infrared spectra of four quasars (QSOs) at z≃1.5 containing the redshifted Hα, Hβ, and[O III] emission lines. The Hα profile in these objects is redshifted on average by 430±170 km s−1 from the systemic velocity derived from [O III] λ5007. This is considerably larger than the Balmer-line velocity shifts measured for low-redshift objects and is consistent with the trend of increasing redshift differences with increasing continuum luminosity. The rest-frame ultraviolet lines in these objects show large (~1000 km s-1) blueshifts from the systemic velocity, and so the large redshifts for Hα are consistent with the dependence of these redshift differences on ionization potential. These results also show that the systemic velocities of very luminous QSOs are accurately measured only from narrow emission lines.