Astronomers generate image equivalent to telescope 63,000 miles wide
The cosmos came into sharper focus this week with astronomers releasing the highest resolution astronomical image yet. The product of 15 earthbound radio telescopes and a Russian satellite, the image of a black hole in a galaxy 900 millions light years away is detailed enough to show the equivalent of a US 50-cent piece on the Moon.
According to Instituto de Astrofísica de Andalucía (IAA-CSIC), which is leading the project, the image is the product of six European radio telescopes, the nine dishes of the US National Science Foundation's Very Long Baseline Array (VLBA), and the Spektr-R satellite of the RadioAstron mission.
The data from these were combined by the Max Planck Institute for Radio Astronomy in Bonn using a technique called interferometry, which is a way of turning a number of optical or radio telescopes distributed across an area into one gigantic telescope. It does this by combining the images from these telescopes so they interfere with one another. By analyzing the amplitude and phase of the interference patterns, scientists can generate a new image of much higher resolution.
In this case, the analysis created an image with the resolution of a telescope about 63,000 mi (101,000 km) wide, which is eight times the diameter of the Earth and resolves objects down to 20 micro-arcseconds of arc.
The radio image shows jets of gas blast away in opposite directions at nearly the speed of light from a black hole 200 million times the mass of the Sun in the galaxy of BL Lacertae. To give a sense of scale of the object and the image resolution, the black hole and its jets would barely fit within the confines of our Solar System as it stretched across the width of the Oort Cloud, which marks our system's outer boundary.
Known as an Active Galactic Nucleus (AGN), the supermassive blackholes are among the most energetic objects in the Universe. They draw in matter from the surrounding galaxy to form an accretion disc, which orbits the hole as a steady stream of gas falls into the event horizon. Meanwhile, twisted magnetic fields at the axis shoot out vast jets of highly energetic plasma that glows in the microwave region of the spectrum. The new image not only confirms the existence of the fields, but provides an insight into their nature.
"Our current understanding of how the emission is generated in AGN establishes a clear limit on the intensity of microwaves that their cores can produce over long time spans," says José L. Gómez, the team leader at the IAA-CSIC. "The extreme intensity observed in BL Lacertae exceeds that limit, requiring either velocities in the jet even closer to the speed of light than thought before or a revision of our theoretical models."
The research results were published in the Astrophysical Journal.
The video below details the VLBA image.