论文标题
斯隆数字天空调查回响映射项目：亮度变化时宽发射线的宽度如何变化
The Sloan Digital Sky Survey Reverberation Mapping Project: How Broad Emission Line Widths Change When Luminosity Changes
论文作者
论文摘要
类星体广泛的发射线在很大程度上由积聚连续体的光电离能。增加的中央光度将增强较远的云层的线发射率，从而导致宽线发射云的平均距离增加，并减少平均线宽度，称为宽线区域（BLR）“呼吸”。但是，不同的线呼吸不同，某些高电离线（例如C IV）甚至可以显示出“反呼吸”，而当亮度增加时线扩大。使用Sloan Digital Sky调查回响映射项目中的多年光度和光谱监测数据，我们量化了H $α$，H $β$，H $β$，MG II，C II，C IV和C III的呼吸效应（$δ$ log W = $ log w = $ log w = $ log w = $ log w = $αδ$ log l），用于固定的准Quasar samples $ z \ y左右。我们发现，h $β$显示出最一致的正常呼吸（$α\ sim-0.25 $），毫克II和h $α$平均显示出没有呼吸显示（$ a \ sim 0 $），以及C IV（以及类似地显示CIII]和SI IV，并且大部分均显示出抗元素的含量（均为$ a $ $ a $ al $α> 0> 0> 0.> 0.> 0. presence of a non-varying core component in addition to a reverberating broad-base component, consistent with earlier findings. The deviation from canonical breathing introduces extra scatter (a luminosity-dependent bias) in single-epoch virial BH mass estimates due to intrinsic quasar variability, which underlies the long argued caveats of C IV single-epoch masses. Using the line dispersion instead of FWHM leads to less,尽管在大多数情况下仍然存在巨大的差异，但我们的结果却加强了回响映射以提供可靠的类星体BH质量，并根据各种线量化了单位BH质量的可变性诱导的偏差水平。
Quasar broad emission lines are largely powered by photoionization from the accretion continuum. Increased central luminosity will enhance line emissivity in more distant clouds, leading to increased average distance of the broad-line-emitting clouds and decreased averaged line width, known as the broad-line region (BLR) "breathing". However, different lines breathe differently, and some high-ionization lines, such as C IV, can even show "anti-breathing" where the line broadens when luminosity increases. Using multi-year photometric and spectroscopic monitoring data from the Sloan Digital Sky Survey Reverberation Mapping project, we quantify the breathing effect ($Δ$log W=$αΔ$log L) of broad H$α$, H$β$, Mg II, C IV, and C III] for statistical quasar samples over $z\approx 0.1-2.5$. We found that H$β$ displays the most consistent normal breathing expected from the virial relation ($α\sim-0.25$), Mg II and H$α$ on average show no breathing ($α\sim 0$), and C IV (and similarly C III] and Si IV mostly shows anti-breathing ($α>0$). The anti-breathing of C IV can be well understood by the presence of a non-varying core component in addition to a reverberating broad-base component, consistent with earlier findings. The deviation from canonical breathing introduces extra scatter (a luminosity-dependent bias) in single-epoch virial BH mass estimates due to intrinsic quasar variability, which underlies the long argued caveats of C IV single-epoch masses. Using the line dispersion instead of FWHM leads to less, albeit still substantial, deviations from canonical breathing in most cases. Our results strengthen the need for reverberation mapping to provide reliable quasar BH masses, and quantify the level of variability-induced bias in single-epoch BH masses based on various lines.
