“The farther we look back into space the farther we see back in time,” explained Rauch.” We were actually trying to measure a faint signal from intergalactic gas caused by the cosmic ultraviolet background radiation. But as often happens in science, we got a surprise and found something we weren't looking for—dozens of faint, discrete objects emitting radiation from neutral hydrogen in the so-called Lyman alpha line, a fundamental signature of protogalaxies.”
The team used the European Southern Observatory's Very Large Telescope, for an unprecedented 92 hours, to expose a spectrum of the universe when it was only 2 billion years old. Most astronomers believe that when the universe was young it was filled with a thin, almost uniform gas. A popular theory of galaxy formation predicts that the gas accreted forming smaller protogalaxies, which then collided and merged to become the massive galaxies seen today. The new discovery lends strong support to this theory.
During the 1990s there was mounting evidence in favor of this hierarchical picture of galactic evolution, including measurements of distant quasars by Rauch and collaborators that showed how the properties of cosmic gas clouds—the reservoir of matter for galaxy formation—fit within that scheme.
“Most of those gas clouds are dark and visible only as foreground objects, which cast something of a shadow against a bright background quasar,” Becker said. “Intriguingly, one class of these shadows—known as damped Lyman alpha systems—was suspected to arise when those small, protogalactic building blocks intersect the line-of-sight to the quasar. For many years, these shadows were our only hint that a population of numerous early galaxies existed.”
Until now this possibility could not be tested because these protogalaxies, with their low masses and tiny stellar populations, were too faint for observations. The weak light signal that the team has now detected from these objects implies low star formation rates and a still small amount of chemical enrichment, as expected for young galaxies. The objects are about 20 times more common than all the distant galaxies ever seen from ground-based surveys, a finding consistent with the properties of the puzzling damped Lyman alpha shadows and with the abundance of early low-mass protogalaxies in the hierarchical picture.
New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship
Solar wind impacts on giant 'space hurricanes' may affect satellite safety
19.09.2017 | Embry-Riddle Aeronautical University
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...
Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.
Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...
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