World’s Most Sensitive Radio Telescope Peeks at Our Local Supermassive Black Hole

A multi-year project to explore the universe in new ways is one step closer to completion. South Africa has finally switched on a highly sensitive radio telescope called MeerKAT, which is part of a global project called the Square Kilometer Array. With MeerKAT online, scientists can scan the sky and peer through the dust and gas obscuring the view of traditional telescopes. To show what the array can do, researchers have released the above image of the core of the Milky Way. Yes, that’s a black hole.

MeerKAT consists of 64 dishes, each one 13.5 meters in diameter. Because it sees in radio frequencies instead of the visual spectrum, it can collect data from objects that are hidden within clouds of dust and gas. Parts of the instrument have been collecting such data since construction began back in 2016, but only now is the instrument up to full-strength. The above image is the first one captured with the complete MeerKAT array.

That image depicts the center of our galaxy, which is home to a supermassive black hole called Sagittarius A* (pronounced Sagittarius A Star). Being in the galactic plane as we are, it’s difficult to collect any data at all on this object in the visual spectrum. MeerKAT uses a technique called interferometry, allowing all the separate dishes to act as a single instrument. Each one collects infinitesimally faint radio signals from the sky so they can be combined and filtered to produce data that astronomers can use.

The bright central flare in the first MeerKAT image is Sagittarius A* some 25,000 light years away. Around that are other intense radio sources like supernova remnants and star-forming regions closer to the center of the galaxy. As for those filaments all over the image, that’s a bit of a mystery. They only exist near Sagittarius A*, but they could be a feature of all supermassive black holes when viewed from relatively close by.

Work to integrate the MeerKAT with other Square Kilometer Array instruments won’t start until around 2020. The project, which will cover large swaths of land in South Africa and Australia, will eventually become the largest radio telescope in the world. As the name implies, the goal is to have a square kilometer of total collection surface area. The project could be complete as soon as 2022. MeerKAT itself will be conducting observations on its own in several months.

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