Dark matter

Scheme of Hubble and Gaia at work (Image NASA, ESA, and A. Feild (STScI))

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An article published in the journal “The Astrophysical Journal” describes a new measurement of the expansion of the universe. A team of astronomers led by Nobel Prize winner Adam Riess combined observations made with the Hubble Space Telescope and those made with ESA’s Gaia space probe, an observatory that specifically aims to map billions of objects in the sky including the variable stars called Cepheid variable used for those measurements. The new results increase the accuracy but also the discrepancy between the measures of the expansion of the near universe and those of the early universe.

The cosmic web in two moments

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An article published in the journal “Nature Astronomy” describes the creation of a map of the network of filaments that connects matter all around the universe. A team of researchers analyzed the data collected during previous surveys to find the gravitational effects that reveal the shapes of those filaments. Those small gravitational distortions suggest that they’re hundreds of millions of light years long and that they’re made of dark matter.

Icarus (MACS J1149+2223 Lensed Star 1)

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An article published in the journal “Nature Astronomy” describes the observation of the most distant star and therefore also the oldest observed so far, nicknamed Icarus, about 9 billion light years from Earth. A team of researchers exploited a double gravitational lensing effect that magnified the image of the star, which was called MACS J1149+2223 Lensed Star 1 but for that reason it’s simply called Lensed Star 1 (LS1). That effect made it become bright enough to be detectable by the Hubble Space Telescope.

The galaxy NGC 1052-DF2 (Image NASA, ESA, and P. van Dokkum (Yale University))

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An article published in the journal “Nature” describes a research on the ultra-diffuse galaxy NGC 1052-DF2. A team of researchers led by Pieter van Dokkum of Yale University, used a number of telescopes to observe this galaxy’s composition concluding that it contains a very low amount of dark matter. The gravitational effects detected in the galaxies show that generally they contain an amount of dark matter much higher than that of ordinary matter but NGC 1052-DF2 is an exception and therefore must be carefully studied.

Pattern of radio waves (Image courtesy Prof. Rennan Barkana)

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An article published in the journal “Nature” describes a research into the possible evidence of the existence of dark matter. Professor Rennan Barkana of the University of Tel Aviv used data collected by the team of Professor Judd Bowman, who found what could be traces of the first stars born in the universe. Those detections also show what were interpreted as evidence of an interaction between dark matter and baryonic matter, the one also called ordinary matter.