A fast radio burst (FRB) is a high energy astrophysical phenomenon manifested as a transient radio pulse lasting only a few milliseconds. FRBs show a frequency-dependent dispersion consistent with propagation through an ionized plasma.[1] As of March 2015 eleven bursts have been detected, all but one by the Parkes radio telescope.

The origin of FRBs is not known: they are generally thought to be extragalactic due to the anomalously high amount of pulse dispersion observed. It has also been suggested that they may originate from nearby stars.[2] It has also been speculated that they might be signs of extraterrestrial intelligence.[3][4]

FRBs are identified by the date the signal was recorded, as "YYMMDD" - e.g. one on 26 June 2011 would be called FRB 110626.[5] The oldest so far found is FRB 010621. On January 19, 2015, astronomers at Australia's national science agency (CSIRO) reported that, for the first time, a fast radio burst had been observed live (at Parkes).[6]

Closely related to FRBs are Perytons, dispersed pulses which share some of the same characteristics as FRBs, but are of terrestrial origin. Perytons were shown in April 2015 to be due to emissions from premature opening of microwave oven doors in the Parkes observatory cafeteria,[7] while FRBs remain as most likely high energy astrophysical sources.

Lorimer Burst

The burst was discovered in archived data taken in 2001 by the Parkes radio dish in Australia.[8] Analysis of the survey data and found a 30-jansky dispersed burst that occurred in 24 Aug 2001,[1] less than 5 milliseconds in duration, located 3° from the Small Magellanic Cloud. The reported burst properties argue against a physical association with the Milky Way galaxy or the Small Magellanic Cloud. The burst became known as the Lorimer burst.[9] The discoverers argue that current models for the free electron content in the universe imply that the burst is less than 1 gigaparsec distant. The fact that no further bursts were seen in 90 hours of additional observations implies that it was a singular event such as a supernova or merger of relativistic objects.[1] It is suggested that hundreds of similar events could occur every day and, if detected, could serve as cosmological probes.[10]

Radio pulsar surveys such as Astropulse and SETI@home offer one of the few opportunities to monitor the radio sky for impulsive burst-like events with millisecond durations.

Further developments

In 2010 there was a new report of 16 similar pulses, clearly of terrestrial origin, detected by the Parkes radio telescope, and given the name Perytons.[11] In 2015 some Perytons were shown to be generated when microwave oven doors were opened during operation, with emission generated from the magnetron.[12]

In 2013 four bursts were identified that supported the likelihood of extragalactic sources.[5]

An observation in 2012 of an FRB (FRB 121102) in the direction of Auriga in the northern hemisphere using the Arecibo radio telescope has confirmed the extragalactic origin of fast radio pulses by an effect known as plasma dispersion. Victoria Kaspi of the McGill University also confirms the initial estimate of 10,000 FRBs per day over the entire sky.[13]

FRB 140514, caught 'live', was found to be 21% (+/- 7%) circularly polarised.[6]

Hypotheses

Because of the isolated nature of the observed phenomenon, the nature of the source remains speculative. As of 2015, there is no generally accepted explanation. The emission region is estimated to be no larger than a few hundred kilometers. If the bursts come from cosmological distances, their sources must be very bright.[14] One possible explanation would be a collision between very dense objects like collapsing black holes or neutron stars.[8] Blitzars are another proposed explanation.[14] It has been suggested that there is a connection to gamma ray bursts.[15][16] It has also been proposed that if FRBs originate in black hole explosions, FRBs would be the first detection of quantum gravity effects.[8][17]

List of bursts

name date-time
UTC for 1581.804688 MHz
RA
J2000
dec
J2000
DM
cm−3pc
DM/187.5
(rounded)[18]
width
ms
peak flux
Jy
notes
FRB 010621[19] 2001/06/21 13:02:10.795 18h52′ -08°29′ 746 3.9 7.8 0.4
FRB 010724[1] 2001/07/24 19:50:01.63 01h18′06″ -75°12′19″ 375 2.0 4.6 30 (Lorimer Burst)
FRB 011025[20] 2001/10/25 00:29:13.23 19h07′ -40°37′ 790 4.2 9.4 0.3
FRB 110220[5] 2011/02/20 01:55:48.957 22h34′ -12°24′ 944.38 5.0 5.6 1.3
FRB 110627[5] 2011/06/27 21:33:17.474 21h03′ -44°44′ 723.0 3.9 <1.4 0.4
FRB 110703[5] 2011/07/03 18:59:40.591 23h30′ -02°52′ 1103.6 5.9 <4.3 0.5
FRB 120127[5] 2012/01/27 08:11:21.723 23h15′ -18°25′ 553.3 2.9 <1.1 0.5
FRB 121002[21] 2012/10/02 13:09:18.402 18h14′ -85°11′ 1628.76 8.7 2.1,3.7 0.35 double pulse 5.1 ms apart
FRB 121102[22] 2012/11/02 06:35:53.244 05h32′ 33°05 557 2.9 3.0 0.4 by Arecibo RT
FRB 131104[23] 2013/11/04 18:04:01.2 06h44′ -51°17′ 779.0 4.1 <0.64 Carina Dwarf Spheroidal Galaxy
FRB 140514[24] 2014/05/14 17:14:11.06 22h34′ -12°18′ 562.7 3.0 2.8 0.47

References

  1. ^ a b c d
  2. ^ "Fast Radio Bursts Might Come From Nearby Stars", Harvard-Smithsonian centre for Astrophysics, December 12, 2013
  3. ^
  4. ^
  5. ^ a b c d e f
  6. ^ a b
  7. ^ "Identifying the source of Perytons at the Parkes radio telescope" 2015
  8. ^ a b c
  9. ^
  10. ^
  11. ^
  12. ^ "Identifying the source of perytons at the Parkes radio telescope", Cornell University Library, April 9, 2015
  13. ^ "Radio-burst discovery deepens astrophysics mystery" July 10 2014, Max Planck Inst
  14. ^ a b "A Brilliant Flash, Then Nothing: New “Fast Radio Bursts” Mystify Astronomers", Scientific American July 9, 2013
  15. ^
  16. ^
  17. ^
  18. ^
  19. ^ arXiv:1206.4135
  20. ^ arXiv:1407.0400
  21. ^
  22. ^ arXiv:1404.2934 Fast Radio Burst Discovered in the Arecibo Pulsar ALFA Survey
  23. ^ arXiv:1412.1599
  24. ^ arXiv:1412.0342