The Event Horizon Telescope (EHT) Collaboration, which published the first image of a black hole in the nearby radio galaxy M 87 has observed the finest detail ever seen in a jet produced by a supermassive black hole using the EHT data on the distant quasar 3C 279. that contains a black hole about one billion times more massive than our Sun in a galaxy 5 billion light-years away in the constellation Virgo that scientists classify as a quasar because an ultra-luminous source of energy at its center shines and flickers as gas falls into a giant black hole.
Twin fire-hose-like jets of plasma erupt from the black hole and disk system at velocities close to the speed of light: a consequence of the enormous forces unleashed as matter descends into the black hole’s immense gravity.
This new analyses –a continuation of the EHT effort from the groundbreaking data collected in its global campaign in April 2017–led by Jae-Young Kim from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, enabled the collaboration to trace the jet back to its launch point, close to where violently variable radiation from across the electromagnetic spectrum arises.
The EHT team spent over a decade simulating an Earth-sized computational telescope that combined the signals received by eight radio telescopes working in pairs around the world. Using this technique, in April of 2019, they were able achieve an unprecedented resolution and observe Galaxy M87 black hole’s silhouette for the first time in history, confirming theoretical predictions about these celestial objects.
To capture the new image, the EHT uses a technique called very long baseline interferometry (VLBI), which synchronizes and links radio dishes around the world. By combining this network to form one huge virtual Earth-size telescope, the EHT is able to resolve objects as small as 20 micro-arcseconds on the sky—the equivalent of someone on Earth identifying an orange on the Moon. Data recorded at all the EHT sites around the world is transported to special supercomputers at MPIfR and at MIT’s Haystack Observatory, where they are combined. The combined data set is then carefully calibrated and analyzed by a team of experts, which then enables EHT scientists to produce images with the finest detail possible from the surface of the Earth.
For 3C 279, the EHT can measure features finer than a light-year across, allowing astronomers to follow the jet down to the accretion disk and to see the jet and disk in action. The newly analyzed data show that the normally straight jet has an unexpected twisted shape at its base and, revealing features perpendicular to the jet that could be interpreted as the poles of the accretion disk where the jets are ejected. The fine details in the images change over consecutive days, possibly due to rotation of the accretion disk, and shredding and infall of material, phenomena expected from numerical simulations but never before observed.
“For 3C 279, the combination of the transformative resolution of the EHT and new computational tools for interpreting its data have proved revelatory,” says Avery Broderick, an astrophysicist working at the Perimeter Institute, explains. “What was a single radio ‘core’ is now resolved into two independent complexes. And they move—even on scales as small as light-months, the jet in 3C 279 is speeding toward us at more than 99.5% of light speed!”
Illustration of multiwavelength 3C 279 jet structure in April 2017. The observing epochs, arrays, and wavelengths are noted at each panel. Credit: J.Y. Kim (MPIfR), Boston University Blazar Program (VLBA and GMVA), and Event Horizon Telescope Collaboration
“This extraordinary optical illusion arises because the material is racing toward us, chasing down the very light it is emitting and making it appear to be moving faster than it is,” clarifies Dom Pesce, a postdoctoral fellow at the Center for Astrophysics | Harvard & Smithsonian (CfA), about the jet in 3C 279, which appears to move at about 20 times the speed of light. “The unexpected geometry suggests the presence of traveling shocks or instabilities in a bent, rotating jet, which might also explain emission at high energies such as gamma-rays.”
“The EHT array is always improving,” explains Shep Doeleman of the Harvard CfA, EHT Founding Director. “These new quasar results demonstrate that the unique EHT capabilities can address a wide range of science questions, which will only grow as we continue to add new telescopes to the array. Our team is now working on a next-generation EHT array that will greatly sharpen the focus on black holes and allow us to make the first black hole movies.”
Source: J. -Y Kim et al. Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution, Astronomy & Astrophysics (2020). DOI: 10.1051/0004-6361/202037493
Journal information: Astronomy & Astrophysics
The Daily Galaxy, Max Goldberg, via Event Horizon Telescope