Greenland Telescope @Denmark

The Event Horizon Telescope (EHT) — a planet-scale array of eight ground-based radio telescopes forged through international collaboration — was designed to capture images of a black hole. In coordinated press conferences across the globe, EHT researchers revealed that they succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow. The shadow of a black hole seen here is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across. While this may sound large, this ring is only about 40 microarcseconds across — equivalent to measring the length of a credit card on the surface of the moon. Although the telescopes making up the EHT are not physically connected, they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations. These observations were collected at a wavelength of 1.3 mm during a 2017 global campaign. Each telescope of the EHT produced enormous amounts of data – roughly 350 terabytes per day – which was stored on high-performance helium-filled hard drives. These data were flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration.

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Welcome

This is the online focal point for astronomers in Denmark interested in joining the Greenland Telescope (GLT) — a project led by ASIAA and SAO. The Danish effort to join the GLT is lead by the Danish National Space Institute at Denmarks Technical University and the Niels Bohr Institute at Copenhagen University.

The GLT is a 12 meter radio antenna currently located at Thule Airforce Base in Greenland. Eventually, the telescope will be operated from the peak of the ice sheet in central Greenland.

As part of the Event Horizon Telescope (EHT) – a world-wide network of telescopes – the GLT will study the central supermassive black holes in nearby galaxies. When not observing as part of the EHT network, the GLT will study distant galaxies and star formation in our own Galaxy.

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