The spectral properties of a large sample of quasars.
The spectral properties of a large sample of quasars.
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DOI：
10.1086/157640
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发表时间：
1980-01
期刊：
影响因子：
--
通讯作者：
D. Richstone;M. Schmidt
中科院分区：
文献类型：
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作者：
D. Richstone;M. Schmidt
用Hale多道光谱仪获得了85个类星体的低分辨光谱测量结果。光谱符合幂函数，光谱指数(dlogf/subv//dlogv)范围为+0.3~-2.5。射电连续谱特性与光学连续谱或谱线特性之间没有明显的相关性。连续谱指数与红移或亮度无关，在幂函数近似的残差中出现一个宽波，在波长=2000A和波长=4400A附近出现亏损，在波长=3000A附近出现过剩，过剩部分是由于巴尔默连续发射，也可能是由于直径约为1光周的12,000K天体的热发射。这不可能是由于含有氢的恒星造成的。在波长=2000A附近的缺陷可能是由于颗粒。相当于L的宽度…阿尔法帽。与C IV的1549条谱线进行了关联，C IV的谱线与类星体连续谱光度呈反相关。相当于L的宽度..阿尔法帽..与光谱指数的相关性很弱，而H.β.+(O III)的光谱指数与光谱指数不相关。这些结果最容易用类星体附近的紫外光电离气体来解释。莫尔？连续介质指数分布，其锐利截止在1/3附近，用连续辐射的类似同步加速器的过程来解释。
Low resolution spectrophotometry of 85 quasars has been obtained with the Hale Multichannel Spectrometer. The spectra are well approximated by power laws, with spectralindices (d logf/sub v//d logv) ranging from +0.3 to -2.5. There is no apparent correlation between the radio continuum properties and either the optical continuum or line properties. There is no dependence of the continuum spectra indices on redshift or luminosity.A broad wave is seen in residuals from the power-law approximation, which appears as a deficiency near lambda=2000 A and lambda=4400 A, and an excess centered near lambda=3000 A. The excess is partly due to the Balmer continuum in emission and may also be partly due to thermal emission from a 12,000 K object about 1 light-week across. It cannot be due to stars containing hydrogen. The deficiency near lambda=2000 A is probably due to grains.The equivalent widths of the L..cap alpha.. and C IV 1549 lines are correlated, and that of C IV is anticorrelated with quasar continuum luminosity. The equivalent width of L..cap alpha.. is weakly correlated with spectral index, but that of H..beta..+(O III) is not. These results are most readily explained in terms of ionization of gas near the quasar by UV photons.Themore » continuum index distribution, with its sharp cutoff near 1/3, is interpreted in terms of a synchrotron-like process for the continuum emission.« less