High resolution spectra of typical wind diagnostics ([OI] 6300 A and other forbidden emission lines) can often be decomposed into multiple components: high-velocity components with blueshifts up to several 100 km/s are usually attributed to fast jets, while narrow (NLVC) and broad (BLVC) low-velocity components are believed to trace slower disc winds. Under the assumption that the line-broadening is dominated by Keplerian rotation, several studies have found that the BLVCs should trace gas launched between 0.05 and 0.5 au and correlations between the properties of BLVCs and NLVCs have been interpreted as evidence for the emission tracing an extended MHD wind and not a photoevaporative wind. We calculated synthetic line profiles obtained from detailed photoionisation calculations of an X-ray photoevaporation model and a simple MHD wind model and analyzed the emission regions of different diagnostic lines and the resulting spectral profiles. The photoevaporation model reproduces most of the observed NLVCs but not the BLVCs or HVCs. The MHD model is able to reproduce all components but produces Keplerian double peaks at average inclinations that are rarely observed. The combination of MHD and photoevaporative winds could solve this problem. Our results suggest that the Gaussian decomposition does not allow for a clear distinction of flux from different wind regions and that the line broadening is often dominated by the velocity gradient in the outflow rather than by Keplerian rotation. We show that observed correlations between BLVC and NLVC do not necessarily imply a common origin in an extended MHD wind.

中文翻译：

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X射线光蒸发和分析MHD模型对原行星盘风诊断线的解释

典型风诊断（[OI] 6300 A 和其他禁止发射线）的高分辨率光谱通常可以分解为多个分量：蓝移高达数百公里/秒的高速分量通常归因于快速喷流，而狭窄的（ NLVC) 和宽 (BLVC) 低速分量被认为可以追踪较慢的盘风。假设线加宽由开普勒旋转主导，几项研究发现 BLVC 应该追踪在 0.05 和 0.5 au 之间发射的气体，并且 BLVC 和 NLVC 的特性之间的相关性已被解释为发射追踪扩展的证据MHD 风而不是光蒸发风。我们计算了从 X 射线光蒸发模型和简单 MHD 风模型的详细光电离计算中获得的合成线剖面，并分析了不同诊断线的发射区域和由此产生的光谱剖面。光蒸发模型重现了大部分观察到的 NLVC，但不是 BLVC 或 HVC。MHD 模型能够重现所有组件，但会在很少观察到的平均倾角处产生开普勒双峰。MHD和光蒸发风的结合可以解决这个问题。我们的结果表明，高斯分解不允许明确区​​分来自不同风区的通量，并且线加宽通常由流出中的速度梯度而不是开普勒旋转控制。