Twisted magnetic field observed around Milky Way’s black hole

WASHINGTON: Astronomers on Wednesday announced that they have detected a strong and organised magnetic field twisted in a spiral pattern around the Milky Way’s supermassive black hole, revealing previously unknown qualities of the immensely powerful object lurking at the center of our galaxy.

The structure of the magnetic field emanating from the edge of the black hole called Sagittarius A*, or Sgr A*, closely resembles one surrounding the only other black hole ever imaged, a larger one residing at the centre of a nearby galaxy called Messier 87, or M87, the researchers said. This indicates that strong magnetic fields may be a feature common to black holes, they added.

The magnetic field around the M87 black hole, called M87*, enables it to launch powerful jets of material into space, the researchers said. This indicates that while such jets have not been detected to date around Sgr A*, they might exist — and might be observable in the near future, they added.

The researchers released a new image showing the environment around Sgr A* in polarised light for the first time, revealing the magnetic field structure. The polarised light comes from subatomic particles called electrons gyrating around magnetic field lines.

Sgr A* possesses 4 million times the mass of our sun and is located about 26,000 light-years — the distance light travels in a year, 5.9 trillion miles (9.5 trillion km) — from Earth.

“For a while, we’ve believed that magnetic fields play a key role in how black holes feed and eject matter in powerful jets,” said astronomer Sara Issaoun of the Centre for Astrophysics — Harvard & Smithsonian and co-leader of the research.