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Home / Science / We’ve seen more fast radio bursts, but we still don’t know what they are

We’ve seen more fast radio bursts, but we still don’t know what they are



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Enlarge / ASKAP antennas of the CSIRO at the Murchison radio astronomy observatory in Western Australia, 2010.

Some of the greatest mysteries of science are in space. The identity of dark matter and dark energy involves fundamental questions about how the Universe is built. If instead you are interested in the mysteries about what the Universe is doing, then fast radio bursts may be at the top of the list of puzzles.

They are, as their name suggests, fast, which last only a handful of milliseconds. And they also involve huge amounts of energy at radio wavelengths, just as promised. But beyond that, we know almost nothing about them, and we have only seen about 35 from the last count. Their rarity and their transitory nature have helped to prevent them from being better understood

But this week's edition of Nature includes a collection of 20 new observations, all of which occurred from ; beginning of 201

7. Unfortunately, the new explosions do not tell us much about how they are generated. And to make matters worse, they suggest that our best bet to understand it – the only repetitive burst source we know – is probably different from all the other sources we're seeing.

It is possible that we observed fast radio bursting into the past, but their strange behavior – a sudden wave of energy and therefore nothing – makes them look more like a technical problem in the equipment than a real phenomenon. Things are not helped by the fact that we have now created a vast number of potential radio sources in the vicinity of the Earth. But in the end, the scientists were convinced that what they were looking at was real and represented a great source of energy at a great distance, even if it was not clear whether they were in our galaxy or not.

Since they come and go so quickly, it has been difficult to locate them at a specific source: they tend to be detected by large reliefs of the sky, which in general can not give us a precise position. The only exception is a single instance in which a source seemed to produce repeated bursts. This object is 3.7 billion light years away, which suggests we are witnessing large events at a great distance.

So what's up? Without knowing where it is, we can not try to imagine its position to see if there are suggestions in what is currently visible. And we can not search the archive data to see if there was anything unusual in that position before the outbreak.

This prompted people to work on Square Kilometer Array in Australia to use some of the hardware already in use for sky detection to gather additional sources. This is not the only survey of its kind, but it has been quite successful, bringing our well-known examples of fast radio gusts from 36 to 56. These include both the closest explosion still imagined, and the most energetic. [19659004] There are also a couple of apparent models in the data. One is that the emissions of many of the bursts are influenced by specific radio frequencies. This, however, can originate at the source or through some interactions between the radio waves and the material that they cross on their way to Earth. So, it does not tell us much about what's going on. Even the total energy of each given gust seems to have a limit, suggesting that there is an inherent power limit to the process that creates them.

It also seems that there are many; extrapolating the number found all over the sky suggests that there are over 30 bursts happening every day, and perhaps up to 45. Because of the way the hardware used in this survey was set, the same regions of space are been scanned several times, so if there was a repetitive source, it was very likely that it was collected a second time during the survey. Nobody was, a result strong enough to be able to conclude with certainty that at least some sources of flurry are never repeated.

This leaves us stuck in a repeating burst, and here the news is not great. Ideally, we would like the repeater to be as similar as possible to single-shot radios, because it would be an indication that everything we learn from it would apply to all the bursts. But the results collected by various surveys now indicate that the repetitive source is relatively weak compared to transient events. Other data have suggested that most of the fast radio explosions originate in an area with weak or disorganized magnetic fields. The repeater seems to be in an environment with strong magnetic fields.

All this suggests that our best option to study fast radio bursts might not reflect radio blasts more generally.

Overall, this survey certainly helps us to understand the scope of the mystery – we know that these things happen often but generally do not happen more than once. Unfortunately, the results do not seem to do too much to solve the mystery itself.

Nature 2018. DOI: 10.1038 / s41586-018-0588-y (About DOIs).


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