The Role of Galactic Winds on Molecular Gas Emission from Galaxy Mergers
The Role of Galactic Winds on Molecular Gas Emission from Galaxy Mergers
复制标题
银河风对星系合并产生的分子气体排放的作用
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
C. Walker
中科院分区：
文献类型：
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作者：
D. Narayanan;T. J. Cox;B. Kelly;R. Davé;L. Hernquist;T. Di Matteo;P. Hopkins;C. Kulesa;B. Robertson;C. Walker
来自星暴和活动星系核（agn）的星系风被认为在沿着星暴- agn序列驱动星系方面起着重要作用。在这里，我们评估了这些风对星系合并CO发射的影响，特别是在模拟的CO形态和发射在线剖面中寻找星爆和agn反馈驱动的风的特征。我们将三维非lte分子线辐射传输代码与平滑粒子流体动力学（SPH）模拟星系合并相结合，包括恒星形成、黑洞生长、多相星际介质（ISM）以及与恒星形成和黑洞生长相关的风。我们的主要结果是(1)银河风可以驱动质量~108-109 M☉的外流，这可能通过CO发射在线测绘成像。(2)与星暴驱动的风相比，AGN反馈驱动的风能够在更长的时间内驱动可探测到的CO流出，这是因为与恒星形成相比，AGN反馈向ISM传递的能量更大。(3)星系风可以控制合并后星系CO发射的空间范围，并可能是局部高级合并观测到亚千秒尺度CO发射半径的物理动机。(4)与风模式无关，所有模式的CO排放谱线均出现了大于圆速度的二次排放峰。然而，在有风的模型中，这些高速峰值被认为优先对应于风携带的流出气体，而在没有风的模型中则不是这样。在没有风的模型中看到的高速峰值通常局限于（来自系统的）速度偏移量≤1.7倍的圆速度，而在有agn反馈驱动的风的模型中，高速峰值可以达到~2.5倍的圆速度。
Galactic winds from starbursts and active galactic nuclei (AGNs) are thought to play an important role in driving galaxies along the starburst-AGN sequence. Here, we assess the impact of these winds on the CO emission from galaxy mergers and, in particular, search for signatures of starburst and AGN-feedback-driven winds in the simulated CO morphologies and emission-line profiles. We do so by combining a three-dimensional non-LTE molecular line radiative transfer code with smoothed particle hydrodynamic (SPH) simulations of galaxy mergers that include prescriptions for star formation, black hole growth, a multiphase interstellar medium (ISM), and the winds associated with star formation and black hole growth. Our main results are (1) Galactic winds can drive outflows of masses ~108-109 M☉ which may be imaged via CO emission-line mapping. (2) AGN-feedback-driven winds are able to drive detectable CO outflows for longer periods of time than starburst-driven winds owing to the greater amount of energy imparted to the ISM by AGN feedback compared to star formation. (3) Galactic winds can control the spatial extent of the CO emission in postmerger galaxies, and may serve as a physical motivation for the subkiloparsec scale CO emission radii observed in local advanced mergers. (4) Secondary emission peaks at velocities greater than the circular velocity are seen in the CO emission lines in all models, regardless of the associated wind model. In models with winds, however, these high-velocity peaks are seen to preferentially correspond to outflowing gas entrained in winds, which is not the case in the model without winds. The high-velocity peaks seen in models without winds are typically confined to velocity offsets (from the systemic) ≲1.7 times the circular velocity, whereas the models with AGN-feedback-driven winds can drive high-velocity peaks to ~2.5 times the circular velocity.