Hubble Space Telescope Space Telescope Imaging Spectrograph Spectroscopy of the Environment in the Starburst Core of M82
Hubble Space Telescope Space Telescope Imaging Spectrograph Spectroscopy of the Environment in the Starburst Core of M82
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DOI：
10.1086/522693
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发表时间：
2007-12
期刊：
影响因子：
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通讯作者：
M. Westmoquette;L. J. Smith;J. Gallagher;R. O’Connell;D. Rosario;R. Grijs
中科院分区：
文献类型：
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作者：
M. Westmoquette;L. J. Smith;J. Gallagher;R. O’Connell;D. Rosario;R. Grijs
我们目前的光学HST STIS的意见，两个狭缝交叉的四个光学最明亮的星暴团附近的核M82。这些提供了Hα运动学，消光，电子密度和发射措施。从径向速度曲线来自两个狭缝，我们证实了恒星酒吧的存在。我们推导出一个新的模型，相对于主星爆团和星团M82-A1的酒吧和磁盘的取向。我们提出，由于棒轨道之间的气体相互作用，在棒区域内形成了块A，而区域C位于棒的边缘，区域D和E位于离核更远的地方，但被严重遮蔽。我们得到了500-900 cm-3的极高星际密度，对应于P/k =（0.5-1.0）× 107 cm-3 K的ISM压力，并讨论了测量的气体性质对银河风产生和演化的影响。尽管不同的压力，电离参数是均匀的秒差距尺度，我们讨论为什么会这样。当我们的光谱的信噪比足够高时，我们识别出多个发射线分量。通过详细的高斯线拟合，我们确定了明亮Hα线的普遍存在的宽（200-300 km s-1）潜在分量，并讨论了可能导致此类宽度的物理机制。我们的结论是，蒸发和/或烧蚀的材料从星际气体云所造成的高能光子和快速流动的集群风的影响产生的云的表面上的排放产生的高度湍流层。
We present optical HST STIS observations made with two slits crossing four of the optically brightest starburst clumps near the nucleus of M82. These provide Hα kinematics, extinction, electron density, and emission measures. From the radial velocity curves derived from both slits we confirm the presence of a stellar bar. We derive a new model for the orientation of the bar and disk with respect to the main starburst clumps and the cluster M82-A1. We propose that clump A has formed within the bar region as a result of gas interactions between the bar orbits, whereas region C lies at the edge of the bar and regions D and E are located farther out from the nucleus but heavily obscured. We derive extremely high interstellar densities of 500-900 cm-3, corresponding to ISM pressures of P/k ≈ (0.5-1.0) × 107 cm-3 K, and discuss the implications of the measured gas properties on the production and evolution of the galactic wind. Despite varying pressures, the ionization parameter is uniform down to parsec scales, and we discuss why this might be so. Where the signal-to-noise ratios of our spectra are high enough, we identify multiple emission-line components. Through detailed Gaussian line fitting, we identify a ubiquitous broad (200-300 km s-1) underlying component to the bright Hα line and discuss the physical mechanism(s) that could be responsible for such widths. We conclude that evaporation and/or ablation of material from interstellar gas clouds caused by the impact of high-energy photons and fast flowing cluster winds produce a highly turbulent layer on the surface of the clouds from which the emission arises.