Up­date on mys­tery flashes from space

A neu­tron star near a black hole may be trans­mit­ting Fast Ra­dio Bursts.

Cosmos - - Digest -

Sorry alien hunters. The lat­est ev­i­dence sug­gests that Fast Ra­dio Bursts, mil­lisec­ond long flashes from deep space, are not stray beams de­signed to power alien space­ships.

Ac­cord­ing to a study in Jan­uary’s Na­ture, the source of a mys­te­ri­ous re­peat­ing Fast Ra­dio Burst (FRB) could be a neu­tron star po­si­tioned close to a su­per­mas­sive black hole.

The first ever recorded FRB was picked up by Aus­tralia’s Parkes Ra­dio Tele­scope in 2001, a five-mil­lisec­ond flash that blazed with the in­ten­sity of 500 mil­lion suns. As­tronomers spot­ted the bizarre sig­nal in 2007 while por­ing through archives.

Since then, many FRBS have been spot­ted, but that hasn’t solved the mys­tery of what could cause such im­mensely pow­er­ful bursts. Can­di­dates have in­cluded col­lid­ing black holes, whiplash from cos­mic strings or, as sug­gested by Har­vard as­tro­physi­cists Avi Loeb and Manasvi Lingam in 2017, “beams used for pow­er­ing large light sails” by ex­tra­galac­tic civil­i­sa­tions.

FRB 121102 is the sub­ject of the lat­est study, “An ex­treme mag­neto-ionic en­vi­ron­ment as­so­ci­ated with the fast ra­dio burst source FRB 121102”.

This FRB was first recorded in 2012 by as­tronomers at the Arecibo Ob­ser­va­tory in Puerto Rico. De­tected 15 times since, it is the only con­firmed re­peat­ing FRB. The fact it re­peats rules out col­lid­ing black holes or neu­tron stars as the source.

Daniele Michilli of the Nether­lands In­sti­tute for Ra­dio As­tron­omy and his col­leagues lo­calised the bursts to a star­form­ing re­gion of a dwarf galaxy three bil­lion light-years away.

Pre­cise mea­sure­ments from the Arecibo tele­scope – con­firmed at the Green Bank Tele­scope in West Vir­ginia – re­vealed the ra­dio wave sig­nals had been dis­torted by pass­ing through an im­mensely pow­er­ful mag­netic field.

Their best ex­pla­na­tion for the bursts? A neu­tron star shrouded by an im­mense mag­netic field. That field could be cre­ated by a black hole, a highly mag­ne­tised wind ne­bula or a su­per­nova rem­nant.

Seems like there is still plenty of mys­tery sur­round­ing FRBS.

CREDIT: VLADYSLAV OTSIATSIAL / GETTY IM­AGES

Not alien ra­dio trans­mis­sions.

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