A mysterious radio source located in the galaxy 500 million light-years from Earth pulsates rhythmically in a 16-day cycle. This is the first time scientists have found a similar frequency in the signals, known as fast radio bursts (FRB), which is an important step toward understanding their sources.
FRB is one of the most obscure mysteries that the universe has thrown to scientists in recent years. First discovered in 2007, these powerful radio bursts are produced by energy sources, although nobody knows what exactly they can be. The mystery of FRB is that they can be either disposable or repetitive, that is, some bursts appear only once in a certain part of the sky, while others emit multiple flashes in the direction of the Earth.
Until now, the impulses of such repeated bursts seemed random and non-cyclic in time. But that changed last year, when Canadian research project on hydrogen radio emission intensity (Canadian Hydrogen the Intensity Mapping Experiment the Fast Burst An Radio by Project, CHIME / FRB ), a group of scientists, dedicated to the observation and study of the FRB, found out that a repeater called FRB 180916.J0158+65 has regular modulation.
The CHIME / FRB team observed a recurring surge from September 2018 to October 2019 with the CHIME radio telescope in British Columbia. During this period, bursts have been grouped into periods of 4 days, and then, apparently, turned off for the next 12 days, which amounted to a total cycle of about 16 days. Some cycles did not produce fixed bursts, but those that did were synchronized at the same 16-day intervals.
Scientists have recently tracked this particular FRB in the galaxy SDSS J015800.28 +654253.0, which is located at a distance of half a billion light-years from Earth. This may seem like a huge distance, but FRB 180916.J0158 +65 is actually the closest ever found.
But although it is known where it is, it is completely unknown what it is. Currently, the dominant concept suggests that the FRB rhythm can be modulated by the source environment. If the FRB source revolves around a compact object, such as a black hole, then it can send its signals to the Earth at a certain point in its orbital period. This scenario could potentially correspond to a detected 16-day cycle.
It is also possible that we are observing a binary system containing a massive star and a superdense stellar core, known as a neutron star, says another study published on arXiv by a separate team of scientists who studied the same data. In their model, a neutron star emits radio bursts, but these signals are periodically eclipsed by dense wind flows from a giant satellite.
Another scenario is that the FRB rhythm does not depend on a foreign object but sends impulses directly from the source. Scientists had previously suggested that flares from highly magnetized neutron stars, called magnetars, could be the source of some FRBs. But since the magnetars rotate every few seconds, the 16-day cycle does not match the expected FRB profile from the magnetar.
Ultimately, the CHIME / FRB team hopes to find similar patterns in several well-known repeating packages to see if these loops are common. Researchers also plan to keep a close eye on FRB 180916.J0158 +65 while it is active, to discover additional details that may indicate its nature.
FRB has been baffling scientists for more than a decade, but new devices such as CHIME reveal new details about these strange objects every year. Although we still don’t know what is the source of these bizarre signals, finding a clear pace from one of these sources is significant progress.