Science Highlight




Imaging the Galactic Center Supermassive Black Hole with the Event Horizon Telescope


(top panel) A representative image of Sgr A* obtained with the EHT from observations on 2017 April 7. This result is obtained by averaging four images (bottom panels) that are produced using DIFMAP, het-imaging, SMILI, and THEMIS.

The Event Horizon Telescope (EHT) Collaboration have published the results of their 2017 1.3 mm observations of Sgr A*, the supermassive black hole in the center of our Galaxy. The EHT observations were conducted using eight stations at six geographic sites - the phased Atacama Large Millimeter/submillimeter Array (ALMA) and APEX in the Atacama Desert in Chile, the JCMT and the phased Submillimeter Array on Mauna Kea in Hawai’i, the SMT on Mt. Graham in Arizona, the IRAM 30 m telescope on Pico Veleta in Spain, the Large Millimeter Telescope Alfonso Serrano on the Sierra Negra in Mexico, and the South Pole Telescope in Antarctica. The data were imaged using a variety of different techniques to ultimately produce compelling evidence for an image of Sgr A* which contains a bright ring of emission with a diameter of ~ 50 μas (Figure 1). This result is consistent with the expected “shadow” of a 4 × 106 solar mass black hole in the center of our Galaxy. 

 ALMA Science