In April 2017, as the Event Horizon Telescope (EHT) collaboration prepared to point the world’s most powerful radio telescopes at the Milky Way’s supermassive black hole, Sagittarius A*, the team calibrated its instruments by observing another cosmic target. Located about 3.7 billion light-years away, J1924–2914 is a blazar: an active black hole that ejects a jet of particles and radiation toward Earth.
The views of J1924–2914 and the other targets of the EHT project are enhanced through very long baseline interferometry, in which multiple telescopes are synchronized to achieve a resolution equivalent to that of a single telescope with a diameter the size of the entire array (see the Quick Study by Dimitrios Psaltis and Feryal Özel, Physics Today, April 2018, page 70). By combining the EHT observations with those also made in April 2017 by two other telescope arrays (one being the Global Millimeter VLBI Array which includes the Green Bank Telescope), the researchers attained images of the black hole.
This news is an excerpt taken from an article in Physics Today. Read more.