基于非参数光谱模型的超大质量早型星系视线速度分布的详细形状
Detailed shapes of the line-of-sight velocity distributions in massive early-type galaxies from non-parametric spectral models
AI总结：
本研究使用非参数建模代码WINGFIT分析9个大质量早型星系的视线速度分布，揭示了复杂的大尺度运动学结构，并在星系中心探测到可能源于PSF效应和微弱恒星晕的宽阔LOSVD“翼”。
摘要：
我们使用新颖的非参数建模代码WINGFIT，对9个大质量早型星系（ETGs）中视线速度分布（LOSVDs）的详细形状进行了首次系统性研究。VLT上MUSE的高信号光谱观测使我们能够在每个星系中测量40到400个独立的LOSVDs，每个光谱bin的信噪比优于100，并能够追踪LOSVDs直至最高恒星速度。我们广泛讨论了由于模板不匹配导致的潜在LOSVD畸变以及避免它们的策略。我们的分析揭示了LOSVDs形状中大量复杂的大尺度运动学结构。最引人注目的是，在我们样本中所有ETGs的中心，我们探测到了微弱、宽阔的LOSVD“翼”，将视线速度v_los延伸到远超3 sigma的范围，在LOSVDs峰值两侧达到v_los = +- 1000 - 1500 km/s。这些翼可能源于PSF效应，并包含了星系极中心未解析区域的视向速度信息。在几个星系中，我们在MUSE视场的外部区域也探测到了形状相似的翼。我们提出这些翼源自ETGs周围松散束缚恒星的微弱晕，类似于在许多最亮团星系周围发现的受团束缚的恒星包层。
英文摘要：
We present the first systematic study of the detailed shapes of the line-of-sight velocity distributions (LOSVDs) in nine massive early-type galaxies (ETGs) using the novel non-parametric modelling code WINGFIT. High-signal spectral observations with MUSE at the VLT allow us to measure between 40 and 400 individual LOSVDs in each galaxy at a signal-to-noise level better than 100 per spectral bin and to trace the LOSVDs all the way out to the highest stellar velocities. We extensively discuss potential LOSVD distortions due to template mismatch and strategies to avoid them. Our analysis uncovers a plethora of complex, large scale kinematic structures for the shapes of the LOSVDs. Most notably, in the centers of all ETGs in our sample, we detect faint, broad LOSVD ``wings'' extending the line-of-sight velocities, v_los, well beyond 3 sigma to v_los = +- 1000 - 1500 km/s on both sides of the peak of the LOSVDs. These wings likely originate from PSF effects and contain velocity information about the very central unresolved regions of the galaxies. In several galaxies, we detect wings of similar shape also towards the outer parts of the MUSE field-of-view. We propose that these wings originate from faint halos of loosely bound stars around the ETGs, similar to the cluster-bound stellar envelopes found around many brightest cluster galaxies.
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