A total of eight new radio signals termed as fast radio bursts (FRBs) have been detected from deep space. One of these signals, FRB 121102 was known to be flashing repeatedly at the beginning of the year while a second signal, FRB 180814 was reported by researchers in January. Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope detected eight repeating signals. The research work has been submitted to The Astrophysical Journal Letters and can be found here.
Currently, a total of 10 repeating FRBs are known that can help the astronomers to figure out more about these signals. These FRBs are spikes in radio data that last only a few milliseconds however possessing the energy of more than 500 million Suns. Tracing the source of FRBs is indeed difficult hence repeaters are important.
As they are not as rare as initially considered, it might be possible to determine the environment from where they originate. Ziggy Pleunis, McGill University said that there are differences between the sources as the bursts are quite irregular. It may not burst for several hours but then multiple bursts can be seen in a short span of time. For FRB 180916.J0158+65, 10 bursts were reported. 6 FRBs only repeated once with the longest pause being more than 20 hours. FRB 181119 repeated three times. These could actually indicate that all FRBs are repeaters with some being more active than others similar to volcanoes. Bursts from repeaters last longer than individual FRBs.
FRB 121102 and FRB 180814 demonstrated a downward frequency drift with each burst getting lower. Pleunis mentioned that there might be some important revelation in the structure to be encoded. CHIME can detect a wide range of lower frequencies unlike ASKAP or the Parkes Observatory in Australia. It can detect one-off bursts however is not optimized to trace sources.
Scientists announced that they were able to localize the eight new repeaters to known galaxies based on the signal direction. It is also possible to determine the distance of the origin of the bursts based on the signal dispersion. FRB 180916 has the lowest dispersion currently which indicates it is located nearby. It can be viewed directly if we know its exact location in the sky.
Signal polarisation also indicates that it came from a very magnetic environment such as black hole as detected in case of FRB 121102. FRB 180916 had a low polarisation indicating that all FRBs do not come from magnetic environments.
It is not yet known whether there are many types of objects producing these signals or if they all repeat or not. But this work is giving some of the answers which will also influence the strategy of other research teams.
Research Paper: https://arxiv.org/abs/1908.03507