A magnetic field 16,000 light-years wide has been detected in an ancient galaxy from which the light is amplified by gravitational lens. Since it is so far away from us, we see this galaxy as it was when it existed more than 11 billion years ago. While all galaxies contain a giant magnetic field, astronomers had never detected galactic magnetism so early in the universe before.
Discovered using Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile, by a multinational team of astronomers led by astrophysicist Jim Geach of the University of Hertfordshire in the UK.
The galaxy, known as 9io9 (short for its full identifier, ASW0009io9), was discovered in 2014 as part of a citizen science project called Space Warps, which was launched in the UK in conjunction with the BBC’s Stargazing Live programme. The project resulted in 7.5 million classifications of lensed galaxies in images taken by the old Canadian-French-Hawaii Telescope (CFHT) survey. The galaxy’s magnification is distorted, and appears as what is known as an Einstein ring. This is a phenomenon that occurs when a distant galaxy, a lenticular foreground object (either a massive galaxy or a cluster of galaxies) and Earth are in nearly perfect alignment across billions of light-years.
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Both in the beginning Leading notes In 2014 9io9 led a team to use ALMA to detect light emitted by interstellar dust grains, which often contain metals, in the distant galaxy. These dust grains align with the galaxy’s magnetic field. This alignment results in the polarization of the long-wavelength light emitted by the dust. When light is polarized, it means that the photons oscillate in a preferred direction. It’s a bit like looking at a galaxy with sunglasses, which only allow light of a certain polarization to pass through.
All galaxies, including our own Milky Way, have a large-scale magnetic field woven into the fabric of galactic clouds of molecular gas and dust. However, the origin of these magnetic fields remains a mystery.
“In fact, we know very little about how these spheres form, despite them being very fundamental to how galaxies evolve,” said Enrique López-Rodriguez of Stanford University, a member of Geth’s team. statement.
We see the 9io9 galaxy in time Universe It was only 2.5 billion years old.
“This discovery gives us new clues about how magnetic fields form on a galactic scale,” said Geach.
In fact, 9io9 tells astronomers that whatever galactic magnetic fields form, they must do so relatively early and quickly.
The detected magnetic field isn’t particularly strong, measuring 500 microgauss or less. This is a thousand times weaker than Earth’s magnetic fieldwhich ranges from 25 to 65 gauss. This is fairly typical for galactic magnetic fields. The Milky Way’s magnetic field is even weaker, only 20-40 microgauss. It is weak because galactic magnetic fields extend over huge distances, which softens it – in the case of 9io9, it spreads across 16,000 light-years.
Getsch’s team suspects that intense bouts of star formation early in 9io9’s life helped spread the magnetic field across the galaxy. In contrast, interconnected galactic magnetic fields across clouds of molecular gas are known to influence subsequent star formation by directing gas and dust streams to common sites. At the convergence of the currents, the gas density and temperature rise until the birth of stars ignites.
The research abstract was published September 6 in the journal Nature.
