THE OPTICAL VARIABILITY OF SDSS QUASARS FROM MULTI-EPOCH SPECTROSCOPY. I. RESULTS FROM 60 QUASARS WITH ⩾ SIX-EPOCH SPECTRA
THE OPTICAL VARIABILITY OF SDSS QUASARS FROM MULTI-EPOCH SPECTROSCOPY. I. RESULTS FROM 60 QUASARS WITH ⩾ SIX-EPOCH SPECTRA
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DOI：
10.1088/0004-637x/792/1/33
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发表时间：
2014-07
期刊：
影响因子：
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通讯作者：
H. Guo 郭;M. Gu
中科院分区：
文献类型：
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作者：
H. Guo 郭;M. Gu
我们从斯隆数字巡天项目中选取了60个类星体样本，用至少6历元光谱法研究了发射谱线和连续光度在各个方面的变化。在2500 Å处，样品的变率与连续光度之间存在很强的反相关关系，这与前人的研究结果一致。在个别来源中，我们发现一半的样本对象遵循越亮越蓝的趋势，而其余一半遵循越亮越红（RWB）的趋势。虽然RWB的机制尚不清楚，但由于观测到变化，宿主星系的影响不能完全排除。正如光电离模型所预期的那样，在大多数单个光源以及整个样品中，宽发射线和连续光谱亮度之间都存在正相关关系。我们在大多数单个物体和整个样本中证实了鲍德温效应，而在几个类星体中也发现了负鲍德温效应，这可能至少部分（如果不是全部）是由于宿主星系的污染。我们发现在大多数单个类星体以及整个样本中，宽发射线亮度与线宽之间存在正相关关系，这意味着线基比线核变化更大。
In a sample of 60 quasars selected from the Sloan Digital Sky Survey with at least six-epoch spectroscopy, we investigate the variability of emission lines and continuum luminosity at various aspects. A strong anti-correlation between the variability and continuum luminosity at 2500 Å is found for the sample, which is consistent with previous works. In individual sources, we find that half of the sample objects follow the trend of being bluer when brighter, while the remaining half follow the redder-when-brighter (RWB) trend. Although the mechanism for RWB is unclear, the effects of host galaxy contribution due to seeing variations cannot be completely ruled out. As expected from the photoionization model, the positive correlations between the broad emission line and continuum luminosity are found in most individual sources, as well as for the whole sample. We confirm the Baldwin effect in most individual objects and the whole sample, while a negative Baldwin effect is also found in several quasars, which can be at least partly (if not all) due to the host galaxy contamination. We find positive correlations between the broad emission line luminosity and line width in most individual quasars, as well as the whole sample, implying a line base that is more variable than the line core.