arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0811.3618astro-ph
收藏

用FUSE对星暴星系的远紫外观测:局域宇宙中的星系反馈

Far-Ultraviolet Observations of Starburst Galaxies with FUSE: Galactic Feedback in the Local Universe

J. P. Grimes, T. M. Heckman, A. Aloisi, D. Calzetti, C. Leitherer, C. L. Martin, G. Meurer, K. Sembach, D. K. Strickland

摘要:

我们分析了16个本地恒星爆发的样本的FUSE远紫外光谱。这些星系的恒星形成率几乎跨越三个数量级,恒星质量超过两个数量级。我们发现,最强的星际吸收线通常是蓝移相对于星系系统速度约50至300公里/秒,这意味着存在恒星爆发驱动的星系外流。外流速度平均随恒星形成率和单位质量恒星形成率的增大而增大。我们发现流出的日冕阶段(T ~几十万K)的气体检测通过OVI 1032吸收线在几乎每个星系。这种流出气体的运动学不同于低电离物质,并且与辐射冷却气体的预测一致(最有可能在X射线追踪的热流出气体和冷环境物质之间的界面处产生)。日冕气体的辐射通常不会被探测到,这意味着这个阶段的辐射冷却不会影响风的动力学/能量学。我们发现,较弱的星际吸收线位于接近系统的速度,这意味着流出的气体有一个较低的柱密度比静止的气体在星爆。从莱曼边缘以下的直接观察和CII 1036线核心处的小剩余强度,我们得出结论,电离辐射的绝对逃逸分数很小(通常小于百分之几)。这个样本提供了一个独特的窗口,对本地星暴星系的全球性质和理解高红移星系光谱有用的比较样本。

英文摘要:

We have analysed FUSE far-UV spectra of a sample of 16 local starbursts. These galaxies span ranges of almost three orders-of-magnitude in star formation rate and over two orders-of-magnitude in stellar mass. We find that the strongest interstellar absorption-lines are generally blueshifted relative to the galaxy systemic velocity by ~50 to 300 km/s, implying the presence of starburst-driven galactic outflows. The outflow velocites increase on-average with the star formation rate and the star formation rate per unit mass. We find that outflowing coronal-phase (T ~ several hundred thousand K) gas detected via the OVI 1032 absorption line in nearly every galaxy. The kinematics of this outflowing gas differs from the lower-ionization material, and agrees with predictions for radiatively cooling gas (most likely created at the interface between the hot outrushing gas traced by X-rays and cool ambient material). Emission from the coronal gas is not generally detected, implying that radiative cooling by this phase is not affecting the dynamics/energetics of the wind. We find that the weaker interstellar absorption lines lie close to the systemic velocity, implying that the outflowing gas has a lower column density than the quiescent gas in the starburst. From direct observation below the Lyman edge and from the small residual intensity at the core of the CII 1036 line, we conclude that the absolute escape fraction of ionizing radiation is small (typically less than a few percent). This sample provides a unique window on the global properties of local starburst galaxies and a useful comparison sample for understanding spectra of high redshift galaxies.

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。

↑