arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1206.2650astro-ph.GA
收藏

银河系中心的电离气体:新的观测和解释

Ionized Gas in the Galactic Center: New Observations and Interpretation

Wesley T. Irons, John H. Lacy, Matthew J. Richter

摘要:

我们提出了新的观测的[Ne II]发射的电离气体在Sgr A西提高分辨率和灵敏度。大约一半的辐射来自气体,运动学表明它在一个从银河平面倾斜约25 \degree \的平面上运行。这一平面与以前推导的环核分子盘和北臂和西弧电离功能是一致的。然而,与大多数以前的研究不同,我们得出结论,电离气体不是沿着电离特征移动,而是沿着更接近圆形的路径移动。观测到的速度接近,但可能略低于中心黑洞和恒星的潜在轨道运动的预期,并有一个小的向内分量。发射的空间分布很好地拟合了螺旋图案。我们讨论了电离气体的空间分布和运动学的可能的物理解释,并得出结论,这两个可能是最好的解释单臂螺旋密度波,这也占所观察到的低速和向内的速度分量。我们认为,密度波可能是由黑洞势和恒星质量分布中的椭圆轨道进动引起的。

英文摘要:

We present new observations of the [Ne II] emission from the ionized gas in Sgr A West with improved resolution and sensitivity. About half of the emission comes from gas with kinematics indicating it is orbiting in a plane tipped about 25\degree\ from the Galactic plane. This plane is consistent with that derived previously for the circumnuclear molecular disk and the northern arm and western arc ionized features. However, unlike most previous studies, we conclude that the ionized gas is not moving along the ionized features, but on more nearly circular paths. The observed speeds are close to, but probably somewhat less than expected for orbital motions in the potential of the central black hole and stars and have a small inward component. The spatial distribution of the emission is well fitted by a spiral pattern. We discuss possible physical explanations for the spatial distribution and kinematics of the ionized gas, and conclude that both may be best explained by a one-armed spiral density wave, which also accounts for both the observed low velocities and the inward velocity component. We suggest that a density wave may result from the precession of elliptical orbits in the potential of the black hole and stellar mass distribution.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑