FRB 20180916B (previously known as FRB 180916.J0158+65, and less formally known as FRB 180916 or "R3"), is a repeating Fast radio burst (FRB) discovered in 2018 by astronomers at the Canadian Hydrogen Intensity Mapping Experiment (CHIME) Telescope. According to a study published in the 9 January 2020 issue of the journal

Nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...

, CHIME astronomers, in cooperation with the radio telescopes at European VLBI Network (VLBI) and the optical telescope

Gemini North The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes prov ...

on Mauna Kea, Hawaii, were able to pinpoint the source of FRB 180916 to a location within a Milky Way-like galaxy named SDSS J015800.28+654253.0. This places the source at

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...

0.0337, approximately 457 million light-years from the Solar System.

Periodicity

Prior to the publication of the study in ''Nature'', only two types of FRBs had been observed: ''Non-Repeaters'' and ''Repeaters''. Non-Repeaters are 'one-off' FRBs, possibly associated with catastrophic stellar events. In contrast, repeaters are not one-off, but instead manifest recurring unpredictable, sporadic, and irregular radiation bursts, their sources are less well understood. FRB 180916 seems to represent a third and new type of FRB that may be termed ''Periodic Repeater''. The radiation activity of FRB 180916 repeats over a period of 16.35 +/-0.18 days. Broadly, FRB 180916 emits a burst of radiation for approximately four days followed by an inactive period of about 12 days, then the cycle repeats. Additional follow-up studies of the repeating FRB by the Swift XRT and UVOT instruments were reported on 4 February 2020; by the Sardinia Radio Telescope (SRT) and Medicina Northern Cross Radio Telescope (MNC), on 17 February 2020; and, by the Galileo telescope in Asiago, also on 17 February 2020. Further observations were made by the

Chandra X-ray Observatory The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 1 ...

on 3 and 18 December, 2019, with no significant x-ray emissions detected at the FRB 180916 location, or from the host galaxy SDSS J015800.28+654253.0. On 6 April 2020, follow-u
studies
by the Global MASTER-Net were reported on

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and, on 4 June 2020, further follow-up studies were reported with the

Giant Metrewave Radio Telescope The Giant Metrewave Radio Telescope (GMRT), located near Pune, Junnar, near Narayangaon at khodad in India, is an array of thirty fully steerable parabolic radio telescopes of 45 metre diameter, observing at metre wavelengths. It is operated by t ...

(uGMRT). On 7 June 2020, astronomers from Jodrell Bank Observatory reported possible evidence that

FRB 121102 In radio astronomy, a fast radio burst (FRB) is a transient radio pulse of length ranging from a fraction of a millisecond to 3 seconds, caused by some high-energy astrophysical process not yet understood. Astronomers estimate the average FRB re ...

exhibits the same radio burst behavior ("radio bursts observed in a window lasting approximately 90 days followed by a silent period of 67 days") every 157 days, suggesting that the bursts may be associated with "the orbital motion of a

massive star A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make ...

, a

neutron star A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white ...

or a

black hole A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

". This behavior is nearly "10 times longer than the 16-day periodicity" exhibited by FRB 180916. In March 2021, another burst from the FRB was reported. On 25 August 2021, further observations were reported.

Structure

The 4-day radiation burst is not homogeneous but is instead characterized by a pattern of ''sub-bursts''. The pattern of radiation activity within the four-day bursts is never exactly repeated. However, there is enough similarity (i.e. alignment of the sub-bursts from period to period) to suggest that they form part of an original repeating pattern with internal structure of some complexity that has undergone distortion in the intervening 457 million years and 5 billion trillion kilometers (approximately). In March 2021, astronomers reported that the area producing pulses of FRB 180916 is about in scale, based on studies at extremely short timescales.

References

Notes

{{portal bar, Astronomy, Science, Space Fast radio bursts Cassiopeia (constellation) Astronomical events