Fast radio burst

A fast radio burst is a brief, intense pulse of radio waves originating beyond the Milky Way, usually lasting milliseconds. Its short duration and large dispersion delay reveal a long journey through ionized matter.

Dispersion measure: The integrated free-electron density along a path, inferred from a radio pulse’s frequency-dependent arrival delay. Its unusually large values show that many bursts crossed substantial ionized matter.
Lorimer Burst: The first reported fast radio burst, detected in archival data from the Parkes radio telescope in 2001. Its 2007 discovery established the phenomenon that later surveys pursued.
Missing baryon problem: The discrepancy between the expected amount of ordinary matter in the universe and the amount directly observed. Burst dispersion measurements help locate diffuse ionized matter that telescopes cannot easily see.
Repeating fast radio burst: A fast radio burst source observed to emit multiple distinct bursts. Repeaters show that at least some progenitors survive their radio outbursts.
Radio wave scattering: The redirection of radio waves by irregularities in a medium, which can broaden or distort pulses. Scattering can stretch burst signals beyond their intrinsic millisecond duration.
Duncan Lorimer: An astrophysicist whose team identified the first reported fast radio burst. His group recognized the 2001 Parkes signal as a likely extragalactic transient.
Warm-hot intergalactic medium: Diffuse intergalactic gas at temperatures of roughly 100,000 to 10 million kelvin. Many baryons are thought to reside in this hard-to-observe gas traced by bursts.
Non-repeating fast radio burst: A fast radio burst source from which no repeated burst has been detected. Whether these sources are distinct from repeaters or merely less active remains unsettled.
Faraday rotation: The rotation of polarized radio waves as they pass through magnetized plasma. Its measurements constrain magnetic fields near some burst sources.
Parkes Observatory: A radio astronomy observatory in New South Wales, Australia, centered on a 64-meter radio telescope. Parkes produced the archival data containing the first reported burst.

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