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High-velocity galactic outflows, driven by intense bursts of star formation and black hole accretion, are 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 on 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 Gyr ago, when the Universe was 20 per cent of its current age): its spatially extended Ly-alpha emission appears to be absorbed by HI in a foreground screen covering the entire galaxy, with a lateral extent of at least 100 kpc and remarkable velocity coherence. It was plausibly ejected from the galaxy during a starburst several 1E8 yr earlier and has subsequently swept up gas from the surrounding intergalactic medium and cooled. This demonstrates the galaxy-wide impact of high-redshift superwinds.
In the early Universe finding massive galaxies that have stopped forming stars present an observational challenge as their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep near-infrared surveys.
During the course of our deep optical imaging survey for Ly alpha emitters at z approximately 5.7 in the field around the z=5.74 quasar SDSSp J104433.04-012502.2, we have found a candidate strong emission-line source. Follow-up optical spectroscopy s
We present the discovery of a massive, quiescent galaxy at z=2.99. We have obtained a HST/WFC3 spectrum of this object and measured its redshift from the detection of a deep 4000A break consistent with an old population and a high metallicity. By ste
When galaxy formation started in the history of the Universe remains unclear. Studies of the cosmic microwave background indicate that the Universe, after initial cooling (following the Big Bang), was reheated and reionized by hot stars in newborn ga
We report on the discovery of a very distant galaxy cluster serendipitously detected in the archive of the XMM-Newton mission, within the scope of the XMM-Newton Distant Cluster Project (XDCP). XMMUJ0044.0-2033 was detected at a high significance lev