New observations of the supermassive black hole at the heart of the galaxy M87 have revealed the origins of its powerful jet and imaged it and its origin together for the first time.
Furthermore, observations of this SMBH have revealed that the black hole's ring is much larger than scientists previously believed. Observations published today in Nature.
The Global mm-VLBI Array (GMVA) brought together radio telescopes from around the world to produce these new results, including the National Radio Astronomy Observatory (NRAO) and the National Science Foundation's Green Bank Observatory (GBO), Atacama Large Millimeter/submillimeter Array (ALMA), Very Long Baseline Array (VLBA) and Green Bank Telescope (GBT).
The SMBH at the center of the galaxy M87 is the most recognizable in the Universe. It was the first black hole captured in an image, created by the Event Horizon Telescope (EHT) and made public in 2019. The image of its dark, dense core framed by a bright amorphous ring made international headlines.
"M87 has been observed for many decades, and 100 years ago we knew the jet was there, but we couldn't place it in context," Ru-Sen Lu, an astronomer at the Shanghai Astronomical Observatory, Max Planck's lead, said in a statement. Research Group of the Chinese Academy of Sciences and lead author of the new paper. "With GMVA, including the main NRAO and GBO instruments, we're looking at a lower frequency, so we're seeing more detail, and now we know there's more detail to see."
Eduardo Ros, astronomer and scientific coordinator for Very Long Baseline Interferometry (VLBI) at the Max Planck Institute for Radio Astronomy added: "We've seen the ring before, but now we see the jet. This puts the ring in context, and it's more big than we thought. If you think of it as a fire-breathing monster, before we could see the dragon and fire, but now we can see the fire-breathing dragon."
Using many different telescopes and instruments gave the team a more complete view of the structure of the supermassive black hole and its jet than was previously possible with EHT, requiring all telescopes to paint a complete picture. While VLBA provided a complete view of both the jet and the black hole, ALMA enabled scientists to resolve M87's bright radio nucleus and create a sharp image. The sensitivity of the GBT's 100-meter collecting surface allowed astronomers to resolve both large- and small-scale parts of the ring and see the finer details.
"The original EHT image revealed only a part of the accretion disk surrounding the center of the black hole. By changing the observation wavelengths from 1.3 millimeters to 3.5 millimeters, we can see more of the accretion disk, and now the jet, at the same time. This revealed that the ring around the black hole is 50 percent larger than previously believed," said scientist Toney Minter, GMVA coordinator for GBT.
The parts of the black hole are not only larger than previously revealed shorter-wavelength observations, but it is now possible to confirm the origin of the jet. This jet was born from the energy created by the magnetic fields surrounding the black hole's spinning core and winds rising from the black hole's accretion disk.
"These results showed, for the first time, where the jet is forming. Before this, there were two theories about its origin," Minter said. "But this observation actually showed that the energy from the magnetic fields and the winds are working together."
Harshal Gupta, NSF Program Officer for Green Bank Observatory, added: "This discovery is a powerful demonstration of how telescopes possessing complementary capabilities can be used to fundamentally advance our understanding of astronomical objects and phenomena. It is exciting to see that the different types of NSF-supported radio telescopes work synergistically as important elements of the GMVA to allow an overview of the M87 black hole and jet."
