A massive cluster of yellowish galaxies, seemingly caught in a red and blue spider web of eerily distorted background galaxies, makes for a spellbinding picture from the new Advanced Camera for Surveys aboard NASA’s Hubble Space Telescope. To make this unprecedented image of the cosmos, Hubble peered straight through the center of one of the most massive galaxy clusters known, called Abell 1689. The gravity of the cluster’s trillion stars — plus dark matter — acts as a 2-million-light-year-wide lens in space. This gravitational lens bends and magnifies the light of the galaxies located far behind it. Some of the faintest objects in the picture are probably over 13 billion light-years away (redshift value 6). Strong gravitational lensing as observed by the Hubble Space Telescope in Abell 1689 indicates the presence of dark matter. Credit: NASA, N. Benitez (JHU), T. Broadhurst (Racah Institute of Physics/The Hebrew University), H. Ford (JHU), M. Clampin (STScI),G. Hartig (STScI), G. Illingworth (UCO/Lick Observatory), the ACS Science Team and ESA Read more at: https://phys.org/news/2017-02-plot-chandra-x-ray-observatory-reveals.html#jCp
A team of space researchers with members from Yale, MIT and Harvard-Smithsonian Center for Astrophysics has found a bump in X-ray readings from the Chandra-X-ray observatory that appears to be similar to bumps seen with X-rays from other telescopes. Such bumps have been theorized to represent the decay of dark matter, which could indirectly prove it exists. Physicists around the globe continue to be perplexed by dark matter and the dearth of evidence showing that it actually exists.
In this new effort, the researchers were looking at X-ray signals from deep space when it came across an unexpected line of X-ray energy at ~3,500 volts. The team suggests that if the bump is due to dark matter, it would likely be caused by such material existing in a region surrounding the Milky Way galaxy. They note that the intensity of the bump is consistent with theories regarding dark matter in other parts of the galaxy such as at the center of the Milky Way—a source of signals that have been found to be stronger, which aligns with logic that suggests dark matter would be denser in places where there are more stars. Also, the bump was similar to readings found by researchers at several other observatories, which reduces the chances of the bump being an anomaly or system malfunction. Oddly, others looking at the same parts of sky have not observed any bump at all.
Unfortunately, the X-ray bump, despite being observed by multiple teams, is not proof of dark matter, because it is still possible that it is due to something else. The finding does, however, rule out some other theoretical sources, such as random sulfur ions seizing electrons from hydrogen atoms hanging around in otherwise empty space. It also seems very unlikely the bump came about due to the type of technology used to observe it. For some, that may leave dark matter as the only possible explanation—others will want something a little more concrete.
https://arxiv.org/abs/1701.07932
https://phys.org/news/2017-02-plot-chandra-x-ray-observatory-reveals.htmljCp
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