Monday, 26 August, 2019

'There could be more out there': Mysterious radio bursts coming from space

The uniquely shaped CHIME telescope in British Columbia The uniquely shaped CHIME telescope in British
Sandy Nunez | 10 January, 2019, 09:55

One of the newly detected bursts is a rare "repeater" - researchers saw six flashes coming from the same spot in the sky, which they hope will make it easier to pin down the source of the signal.

Such signals have only ever been detected once before, by a different telescope.

The finding was also presented at the 233rd meeting of the American Astronomical Society in Seattle.

Dr Ryan Shannon from Swinburne University of Technology said 20 fast radio bursts were detected in a year, "almost doubling the number detected worldwide since they were discovered in 2007".

Known as "fast radio bursts", (FRBs) the repeating nature of the waves makes it possible to track its source, if only for a brief moment.

"By understanding these propagation effects and being able to separate them from the intrinsic characteristics of FRBs, we hope to be able to use FRBs as probes of the electron distribution and magnetic field distribution in the Universe which would tell us about how the Universe built up structures, such as galaxies, galaxy clusters, and so on", explained Tendulkar.

These discoveries are among the first, eagerly awaited results from the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a revolutionary radio telescope inaugurated in late 2017 by a collaboration of scientists that includes MIT's Kiyoshi Masui, an assistant professor of physics, and Juan Mena Parra, a Kavli postdoc. Experts speculate one of these could be the source of FRBs. "We would like to know what kinds of objects these are and how they are related to other explosions and objects that we know of (gamma-ray bursts, supernovae, neutron stars etc)", Tendulkar said.

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Scientists are unsure where the bursts originate, but believe they are created by black holes or super-dense neutron stars, according to the Press Association. And the existence of a second repeater means 2012's was not a fluke or an instrument error - something is producing these repeating bursts of light, and it's clearly fixed in place over long periods of time. Before CHIME, astronomers noted that most of the previously detected bursts had frequencies around 1,400 MHz, and some wondered whether CHIME would detect any bursts at all in its range of 400 to 800 MHz.

The CHIME researchers are working with an array of antennas in central New Mexico to pin down the galaxy to which the second repeater belongs. FRBs are typically in the 1,400 MHz range, and the previous lowest radio frequency was at 700 MHz.

The other institutions with leading roles are the University of Toronto, the National Research Council of Canada, and the Perimeter Institute.

The repeating FRBs were detected during CHIME's trial run earlier this summer, which used only a small amount of the telescope's potential power.

The majority of the 13 FRBs detected showed signs of "scattering", a phenomenon that reveals information about the environment surrounding a source of radio waves.

Added Landecker: "We haven't solved the problem, but it's several more pieces in the puzzle".