| Title | Giant Magnetic Fields in the Universe | |
| Date | Thursday March 23 2017, @06:02AM | |
| Author | takyon | |
| Topic | ||
| from the where's-the-pole? dept. | ||
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal Astronomy & Astrophysics.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the diameter of the Milky Way, they host a large number of such stellar systems, along with hot gas, magnetic fields, charged particles, embedded in large haloes of dark matter, the composition of which is unknown. Collision of galaxy clusters leads to a shock compression of the hot cluster gas and of the magnetic fields. The resulting arc-like features are called "relics" and stand out by their radio and X-ray emission. Since their discovery in 1970 with a radio telescope near Cambridge/UK, relics were found in about 70 galaxy clusters so far, but many more are likely to exist. They are messengers of huge gas flows that continuously shape the structure of the universe.
Radio waves are excellent tracers of relics. The compression of magnetic fields orders the field lines, which also affects the emitted radio waves. More precisely, the emission becomes linearly polarized. This effect was detected in four galaxy clusters by a team of researchers at the Max Planck Institute for Radio Astronomy in Bonn (MPIfR), the Argelander Institute for Radio Astronomy at the University of Bonn (AIfA), the Thuringia State Observatory at Tautenburg (TLS), and colleagues in Cambridge/USA. They used the MPIfR's 100-m radio telescope near Bad Münstereifel-Effelsberg in the Eifel hills at wavelengths of 3 cm and 6 cm. Such short wavelengths are advantageous because the polarized emission is not diminished when passing through the galaxy cluster and our Milky Way. Fig.1 shows the most spectacular case.
Relics in galaxy clusters at high radio frequencies (open, DOI: 10.1051/0004-6361/201629570) (DX) (arXiv)
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printed from SoylentNews, Giant Magnetic Fields in the Universe on 2024-04-19 23:58:15