“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.
First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester
Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy