For the first time we see a black hole and its jet of material

The latest image of the black hole M87* shows a triple-pronged jet emanating from it | Credit: R.-S. Lu (SHAO) and E. Ros (MPIfR), S. Dagnello (NRAO/AUI/NSF)

I’m usually not very good with dates, but if someone asks me what I’m doing on April 10th, 2019… I’ll remember. Like many astronomy and science lovers, I was glued to the computer screen to attend the presentation of the first real image of a black hole. Until that moment, humanity had theorized about its existence for decades, collected hundreds of indirect evidences, analyzed mass, velocity and event horizon data, published thousands of artistic representations … but We’ve never photographed a real black hole.

Then came the huge EHT (Event Telescope) project, a fruitful international collaboration made up of eight radio telescopes spread across the globe. InterferometryIt becomes a gigantic peephole the virtual size of the Earth. This is how the famous photo of the black hole at the center of Messier 87 came about, a massive galaxy located in the Virgo cluster. Located 55 million light-years away, the supermassive black hole M87* shone like a ring with the mass of 6,500 suns in Tolkien’s novels.

This is an image of the black hole at the center of the galaxy M87 obtained by the EHT Network (Event Horizon Telescope) in 2019 | Credit: EHT Collaboration

However, even though this 2019 image has gone down in history, many questions are still up in the air, especially since it doesn’t show any jets of matter that should accompany a black hole. In that image, the EHT radio telescopes were not operating at wavelengths long enough to capture them. Reduce the frequency (so increase the wavelength) to be able to visualize them (3.5 mm instead of 1.3 mm).

Three images of the super black hole M87*. Left: First image released in 2019. Center: The same AI-enhanced image, released this year. Right: M87* at 3.5mm showing its relativistic jets as revealed by GMVA, ALMA and GLT | Nature picture

It has been more than three years since the EHT began direct observation of black holes by interferometry, and a few days ago, Finally published in Nature Image showing M87’s long-awaited relativistic jet. It’s been hard and patient work (the observations used were made between April 14 and 15, 2018) and it’s taken a great new collaboration to get here. This time the data comes from various radio telescope projects around the world GMVA (Universal Millimeter VLBI Array), the soul (Atacama large millimeter/submillimeter order) and the GLT (Greenland Telescope).

The published image clearly shows the connection between the supermassive black hole M87*, its luminous ring and the famous high-velocity jet. And it comes with a surpriseBecause it shows “three arcs associated with the relativistic jet onset, a central spine emerging from the annulus, and two boundary arcs above and below”.

What are these “jets” that come out of black holes?

“Matter falling in a spiral toward a black hole creates what’s called an accretion disk,” the physicist, mathematician, and well-known popularizer explains to Yahoo! Francis Villatoro. “This matter accelerates and gains so much energy that its atoms split into their nuclei and their electrons, creating a plasma. Both the nuclei and the electrons are electrically charged, so they act like electrons in an electrical wire and create a magnetic field. This magnetic field in the disk The lines are closed and form “horseshoes” that go out of the disk and back into it (this also happens on the surface of the Sun). But near the inner edge of the disk the lines are not closed and the black hole’s event horizon is open lines. When the black hole rotates very fast, the horizon is also The empty space between the disk also rotates; open lines of magnetic field are forced to spin in a spiral, escaping upward (perpendicular to the disk) without reaching the horizon. These magnetic field lines pull plasma away from the disk and shoot it out, creating a relativistic jet of matter.”

As is often the case when trying to understand the cosmos, many questions remain unanswered, but the amount of knowledge we can gain from studying a black hole is fascinating. The massive M87* has become the greatest source of discoveries in black hole physics, and observing it using interferometry has proven itself to be a wonderful technique for studying one of the most fascinating phenomena in the universe.