FRBs were first detected in 2007
A radio telescope in China’s Guizhou province has detected a highly active and repeating radio frequency pulse coming from a dwarf galaxy about 3 billion light-years from Earth.
Since they were first detected in 2007, fast radio bursts (FRBs) have puzzled scientists. Observations over the past fifteen years have given rise to a number of hypotheses to explain the origin and underlying physics of these bright bursts of radio waves close to the millisecond duration. Appears this week in an international collaboration magazine Nature A rare example of a dwarf galaxy about 3 billion light years away from Earth.
is about a very active and repetitive signal, Which is also associated with a compact source of radio emission, weak but frequent between bursts. The discovery raises new questions about the nature of these mysterious objects and their usefulness as indirect tools to study the nature of space between galaxies. The new cosmic signal – called FRB 190520 – was detected by the Five Hundred Meter Aperture Spherical Radio Telescope (FAST) in the Chinese province of Guizhou.
An explosion that occurred on 20 May 2019 In November of the same year the telescope data was recorded. In New Mexico (USA) Carl G. Additional investigations at the Jansky Very Large Array (VLA) observatory allowed the location of the object to be identified, which, in turn, opened up the possibility of observing in visible light on the Subaru Telescope. In Hawaii.. Furthermore, data collected in China showed that unlike many other FRBs, it emits frequent and repeated bursts.
“These characteristics mean that it is similar to the first FRB whose position could be established in 2016,” says Casey Law, an astrophysicist at the California Institute of Technology. Separating the location is a fundamental advance, as it allows scientists to extract information about the environment and the distance of the eruption. In the case of the 2016 detection (named FRB 121102), the combination of repeated light pulses and persistent radio emissions from a compact region made it unlike anything seen to date. “Now we have the second one, which raises some big questions,” Law says.
The difference between FRB 190520 and FRB 121102 and the rest of the radio bursts reinforces the hypothesis that can be of two different types, The main candidates for the origin of fast radio bursts are superdense neutron stars (resulting from the explosion of a massive star as a supernova) or neutron stars with ultrastrong magnetic fields, called magnetars. Some astronomers suggest that two different mechanisms will produce the two categories of FRBs, others speculate that the events producing them may show different results at different stages of their development.
On the other hand, a feature of the newly discovered FRB 190520 questions the usefulness of fast radio bursts as an indirect tool for studying material between them and Earth. Astronomers often look at the effects of interfering material on radio waves to learn more about that faint material from outer space. One such effect occurs when radio waves pass through a section of the universe that contains free electrons. In that case, the higher frequency waves travel faster, an effect called dispersion, which can be measured to determine the density of electrons in the space between the object and Earth. Or, if the electron density is known or assumed, they can provide an estimate of the distance to the object. A technique often used to calculate the distance to pulsars.
But it applies in the case of FRB 190520: distance-independent measurements of the Milky Way’s light based on the Doppler effect (due to the expansion of the universe) have allowed it to be established that the distance with Earth is 3,000 million light years. However, the burst signal shows a scattering that would indicate a distance between 8 and 9.5 billion light years. “His vote The FRB has a lot of material, falsifying any attempt to use it to measure gas between galaxies“, explains Kshitij Aggarwal, a researcher at West Virginia University and a co-author of the article. “If so, we cannot rely on FRBs. cosmic norms,
After the initial discovery, new analyzes and more in-depth models have been carried out, including polarization analysis, dispersion time scale models, and supernova origin models. Astronomers raise the possibility that FRB 190520 is much smaller and still surrounded by dense material, derived from a supernova explosion that left behind a neutron star. As that material is destroyed, the propagation of the burst signals also decreases. according to this hypothesis Frequent bursting may also be characteristic of young FRBs and may decrease over time., “We believe that FRB 121102A and FRB 190520B represent an early stage of an evolved eruption population, the authors explain. “A coherent picture of origin and evolution is likely to emerge within a few years.”
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