The EHT collaboration has enabled scientists to produce the highest resolution black hole image ever taken from Earth. This occurred when the global network of telescopes acting as a virtual Earth-sized instrument completed a groundbreaking observation at 345 GHz, setting an unprecedented record for terrestrial astronomy.
This incredible feat involved the detection of light from distant galaxies at 345 GHz, that is 0.87 mm long. The observations at these higher frequencies allowed more detailed imaging of the black hole. EHT expects future black hole images to be 50% sharper; this may reveal new properties that were so far undetectable.
Alexander Raymond, co-lead of the research, highlighted the significance of this milestone. “With the EHT, we saw the first images of black holes by detecting radio waves at 230 GHz, but the bright ring we saw, formed by light bending in the black hole’s gravity, still looked blurry,” Raymond explained. “At 345 GHz, our images will be sharper and more detailed, which in turn will likely reveal new properties, both those that were previously predicted and maybe some that weren’t.”
It was the first observation with the VLBI technique at 345 GHz, and it may be noted that this posed several challenges. Among these are that atmospheric water vapor absorbs signals at this frequency more strongly than on lower frequency observations. making them difficult to observe. The EHT team overcame this by implementing an improvement in the telescope’s sensitivity, increasing bandwidth, and informative planning around optimal weather conditions.
Such a high-resolution observation was only enabled due to the contribution of a number of telescopes including ALMA, APEX, IRAM, NOEMA, SMA, and the Greenland Telescope. The final achieved resolution is 19 microarcseconds. Never before have researchers had such clear eyes on these giants in the sky.