Empirical constraints on the turbulence in QSO host nebulae from velocity structure function measurements
Empirical constraints on the turbulence in QSO host nebulae from velocity structure function measurements
复制标题
速度结构函数测量对 QSO 宿主星云湍流的经验约束
DOI：
10.1093/mnras/stac3193
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发表时间：
2022
影响因子：
4.8
通讯作者：
Boettcher, Erin
中科院分区：
文献类型：
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作者：
Chen, Mandy C.;Chen, Hsiao-Wen;Rauch, Michael;Qu, Zhijie;Johnson, Sean D.;Li, Jennifer I-Hsiu;Schaye, Joop;Rudie, Gwen C.;Zahedy, Fakhri S.;Boettcher, Erin
本文首次给出了≈为0.51.1的四个发光类星体(QSO)周围弥散绕星系介质的湍流速度场的经验约束。在利用甚大望远镜多单元光谱探测器获得的积分场光谱观测中，在[Oii]和/或[Oiii]发射线上发现了直径为≈50-100物理kpc的以类星体为中心的空间扩展星云。我们测量了从≲5 kpc到≈20-50 kpc的一系列尺度上的二阶和三阶速度结构函数(VSF)，以量化这些星云中不同尺度之间的湍流能量传递。虽然目前的数据不能得到能量注入和耗散尺度的约束，但我们表明，在考虑了大气能见度、空间平滑和大尺度体流的影响后，可以确定对VSFs的幂定律斜率的稳健约束。在所研究的四个类星体星云中，有一个星云的VSFs与柯尔莫戈洛夫定律非常一致，预计适用于各向同性、均匀和不可压缩的湍流。其他三个场的VSFs从大到小的下降幅度较小。然而，在视界有限的空间尺度上动态范围有限的情况下，这三个星云的VSF斜率不能得到约束。对于符合柯尔莫戈洛夫定律的类星云，我们确定了≈0.2cm2s−3的湍流能量级联速率。
We present the first empirical constraints on the turbulent velocity field of the diffuse circumgalactic medium around four luminous quasi-stellar objects (QSOs) atz≈ 0.5–1.1. Spatially extended nebulae of ≈50–100 physical kpc in diameter centred on the QSOs are revealed in [Oii]and/or [Oiii]emission lines in integral field spectroscopic observations obtained using Multi-Unit Spectroscopic Explorer on the Very Large Telescope. We measure the second- and third-order velocity structure functions (VSFs) over a range of scales, from ≲5 kpc to ≈20–50 kpc, to quantify the turbulent energy transfer between different scales in these nebulae. While no constraints on the energy injection and dissipation scales can be obtained from the current data, we show that robust constraints on the power-law slope of the VSFs can be determined after accounting for the effects of atmospheric seeing, spatial smoothing, and large-scale bulk flows. Out of the four QSO nebulae studied, one exhibits VSFs in spectacular agreement with the Kolmogorov law, expected for isotropic, homogeneous, and incompressible turbulent flows. The other three fields exhibit a shallower decline in the VSFs from large to small scales. However, with a limited dynamic range in the spatial scales in seeing-limited data, no constraints can be obtained for the VSF slopes of these three nebulae. For the QSO nebula consistent with the Kolmogorov law, we determine a turbulence energy cascade rate of ≈0.2 cm2s−3. We discuss the implication of the observed VSFs in the context of QSO feeding and feedback in the circumgalactic medium.
正在吸收的遥远星系的外围
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
Hsiao
通讯作者：
Hsiao