* Astronomy

Astronomers have mapped the cosmic "scaffold" of dark matter upon which stars and galaxies are assembled.
Dark matter does not reflect or emit detectable light, yet it accounts for most of the mass in the Universe.
The study, published in Nature journal, provides the best evidence yet that the distribution of galaxies follows the distribution of dark matter.
This is because dark matter attracts "ordinary" matter through its gravitational pull.
Scientists presented details of their research during a news conference here at the 209th meeting of the American Astronomical Society (AAS) in Seattle, Washington.

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Very High Frequency Radiation makes Dark Matter Visible
Max Planck researcher from Garching prove that giant radio telescope can deliver high-resolution images showing the cosmic mass distribution
The stars and gas which are seen in galaxies account for only a few percent of the gravitating material in the Universe. Most of the rest has remained stubbornly invisible and is now thought to be made of a new form of matter never yet seen on Earth. Researchers at the Max Planck Institute for Astrophysics have discovered, however, that a sufficiently big radio telescope could make a picture of everything that gravitates, rivalling the images made by optical telescopes of everything that shines.
As light travels to us from distant objects its path is bent slightly by the gravitational effects of the things it passes. This effect was first observed in 1919 for the light of distant stars passing close to the surface of the Sun, proving Einstein's theory of gravity to be a better description of reality than Newton's. The bending causes a detectable distortion of the images of distant galaxies analogous to the distortion of a distant scene viewed through a poor window-pane or reflected in a rippled lake. The strength of the distortion can be used to measure the strength of the gravity of the foreground objects and hence their mass. If distortion measurements are available for a sufficiently large number of distant galaxies, these can be combined to make a map of the entire foreground mass.

This technique has already produced precise measurements of the typical mass associated with foreground galaxies, as well as mass maps for a number of individual galaxy clusters. It nevertheless suffers from some fundamental limitations. Even a big telescope in space can only see a limited number of background galaxies, a maximum of about 100,000 in each patch of sky the size of the Full Moon. Measurements of about 200 galaxies must be averaged together to detect the gravitational distortion signal, so the smallest area for which the mass can be imaged is about 0.2% that of the Full Moon. The resulting images are unacceptably blurred and are too grainy for many purposes. For example, only the very largest lumps of matter (the biggest clusters of galaxies) can be spotted in such maps with any confidence. A second problem is that many of the distant galaxies whose distortion is measured lie in front of many of the mass lumps which one would like to map, and so are unaffected by their gravity. To make a sharp image of the mass in a given direction requires more distant sources and requires many more of them. MPA scientists Ben Metcalf and Simon White have shown that radio emission coming to us from the epoch before the galaxies had formed can provide such sources.

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After decades of intensive effort by both experimental and theoretical physicists worldwide, a tiny particle with no charge, a very low mass and a lifetime much shorter than a nanosecond, dubbed the "axion," has now been detected by the University at Buffalo physicist who first suggested its existence in a little-read paper as early as 1974.
The finding caps nearly three decades of research both by Piyare Jain, Ph.D., UB professor emeritus in the Department of Physics and lead investigator on the research, who works independently -- an anomaly in the field -- and by large groups of well-funded physicists who have, for three decades, unsuccessfully sought the recreation and detection of axions in the laboratory, using high-energy particle accelerators.

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Title: Search for new particles decaying into electron pairs of mass below 100 MeV/c²
Authors: P L Jain, G Singh

We report results on 1220 electron pairs produced from a 207Pb beam at 160 A GeV in nuclear emulsion with invariant mass Q ranging between 1 and 100 MeV and lifetime τ between 10^-15 s and 10^-12 s. These electron pairs were produced at a distance of more than 50 µm from the primary interactions—this distance eliminates contamination due to Dalitz pairs. After subtracting the background pairs from the materialization of photons and also due to the decay of π0 → 2γ from the data, they exhibit enhancement at low mass Q = 6–20 MeV with narrow peaks at 7 ± 1 MeV, 19 ± 1 MeV and τ < 10^-13 s.

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The Soudan 2 detector is located at a depth of 2090 m at latitude 47.819012° N, longitude -92.242023° W in NE Minnesota, USA.


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Latitude:47.815N; Longitude: -92.237W.