Wilman R J, Gerssen J, Bower R G, Morris S L, Bacon R, de Zeeuw P T, Davies R L
Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK.
Nature. 2005 Jul 14;436(7048):227-9. doi: 10.1038/nature03718.
High-velocity galactic outflows, driven by intense bursts of star formation and black hole accretion, are processes invoked by current theories of galaxy formation to terminate star formation in the most massive galaxies and to deposit heavy elements in the intergalactic medium. From existing observational evidence (for high-redshift galaxies) it is unclear whether such outflows are localized to regions of intense star formation just a few kiloparsecs in extent, or whether they instead have a significant impact on the entire galaxy and its surroundings. Here we present two-dimensional spectroscopy of a star-forming galaxy at redshift z = 3.09 (seen 11.5 gigayears ago, when the Universe was 20 per cent of its current age): its spatially extended Lyalpha line emission appears to be absorbed by H i in a foreground screen covering the entire galaxy, with a lateral extent of at least 100 kpc and remarkable velocity coherence. This screen was ejected from the galaxy during a starburst several 10(8) years earlier and has subsequently swept up gas from the surrounding intergalactic medium and cooled. This demonstrates the galaxy-wide impact of high-redshift superwinds.
由强烈的恒星形成爆发和黑洞吸积驱动的高速星系外流，是当前星系形成理论所提出的过程，旨在终止最大质量星系中的恒星形成，并在星系际介质中沉积重元素。从现有的（针对高红移星系的）观测证据来看，尚不清楚这种外流是局限于仅几千秒差距范围内的强烈恒星形成区域，还是会对整个星系及其周围环境产生重大影响。在此，我们展示了一个红移z = 3.09的恒星形成星系的二维光谱（该星系是在115亿年前被观测到的，当时宇宙年龄仅为当前年龄的20%）：其空间扩展的莱曼α线发射似乎被覆盖整个星系的前景中性氢吸收，横向范围至少为100千秒差距，且具有显著的速度相干性。这个气体屏是在早于数10⁸年前的一次星暴期间从星系中喷出的，随后扫过周围星系际介质中的气体并冷却。这证明了高红移超级风对整个星系的影响。
