Space

Astronomers trace the magnetic field of the supermassive black hole at the center of our galaxy

Astronomers trace the magnetic...
Artist's impression of the magnetic field present around the event horizon of Sgr A*
Artist's impression of the magnetic field present around the event horizon of Sgr A*
View 1 Image
Artist's impression of the magnetic field present around the event horizon of Sgr A*
1/1
Artist's impression of the magnetic field present around the event horizon of Sgr A*

A team of astronomershas successfully detected magnetic fields present around the eventhorizon of the supermassive black hole at the centre of our galaxy.It is thought that these magnetic fields are the driving factorbehind a mechanism that sends intense pulses of galaxy sculptingradiation blasting thousands of light-years into space from theevent horizon of a spinning black hole.

Known as SagittariusA-star (Sgr A*), the supermassive black hole that sits at the heartof the Milky Way is a true monster by any standards. It is believedto be incredibly dense, compressing a mass the equivalent of fourmillion times that of our Sun into a space no larger than the planetMercury.

Sgr A* sits roughly25,000 light-years from Earth, a distance which, when combined withthe black hole's relatively diminutive size, would necessitate atelescope of prodigious size in order to capture the phenomenon.Thankfully, we just so happen to have one on hand.

The recent observationswere made using the Event Horizon Telescope (EHT), acolossal virtual telescope that spans the entire globe. The EHT ismade up of many individual radio observatories, which when combinedwill grant the EHT a resolution of 15 arc seconds, the equivalent ofa thousand times the resolution of the Hubble Space Telescope.

Using the EHT, the teamwas able to trace the shape of Sgr A*'s magnetic field by measuringhow light from the black hole is linearly polarized as it spiralsaround magnetic field lines. The observations showed that sections ofthe magnetic field lines were tangled, looping and chaotic, whereasothers appeared to assume amore organized structure.

Furthermore,the characteristics of the black hole itself made the magnetic fieldeasier to characterize, with the gravity from Sgr A* magnifying thelight to make it roughly five times larger when viewed from Earth,placing it within the observational capabilities of the EHT.

The team believes thatthe more stable sections are where the powerful jets of radiationeminate from. The end result of the observation essentially grantsevidential grounding to previous theories on the relationship betweenthe jets and the magnetic field that sits just outside Sgr A*'s eventhorizon.

A paper on thediscovery has been published in the online journal Science.

Source:Harvard-Smithsonian Center for Astrophysics

2 comments
AndrewTomer
"The EHT is made up of many individual radio observatories, which when combined will grant the EHT a resolution of 15 arc seconds, the equivalent of a thousand times the resolution of the Hubble Space Telescope"
(i think the lawyer should have said "15 milli-arcseconds")
the.other.will
Pretty sure the magnetic field doesn't effect light directly. Gases heat & emit light as they spiral down towards the event horizon. The magnetic field effects the gases after they ionize.