Astronomer working on the physics of black holes, especially their observations in the radio wave range. For years, he has been affiliated with the Mikołaj Kopernik Astronomical Center in Warsaw. In 2017, he took a job at Harvard University’s Black Hole Initiative institute and joined the team of the Event Horizon Telescope (EHT), where he worked on designing elements of the observational data reduction path, and since 2018 he has been leading the work of a scientific group dedicated to studying the temporal variability of observed objects. For obtaining the first radio images of supermassive black holes at the center of the M87 galaxy and at the center of our Milky Way, he and the EHT team received a number of prestigious scientific awards, including the Einstein Medal and the Breakthrough Prize in Fundamental Physics. As of fall 2021, he is working at the Max Planck Institute for Radioastronomy in Bonn, Germany.