Congratulations to the 2020 Nobel prize in physics Laureates

The 2020 Nobel Prize in physics has been awarded to astronomers Reinhard Genzel and Andrea Ghez for their parallel discoveries of the supermassive compact object at the center of our Galaxy, and to mathematical physicist Roger Penrose for his theoretical work on black holes.

Over the past 30 years, the teams led by Genzel and Ghez have used telescopes in Chile and Hawaii, respectively, to track the orbits of stars around the very center of the Milky Way. This has shown that its central ~100 astronomical units contain 4 million solar masses and yet have very low luminosity; this result is extremely hard to explain with anything but a black hole. Recently, Reinhard Genzel's team spearheaded the development of the GRAVITY instrument for the Very Large Telescope Interferometer to improve the tracking precision of the Galactic center stars by an order of magnitude. In a series of A&A articles, the team used the exquisite GRAVITY measurements to pinpoint the properties of the central mass, measure the variable gravitational redshift it inflicts on passing stars, observe the Schwarzschild precession of their orbits, and measure the motions of gas clouds near the last stable orbit.

A&A warmly congratulates all three recipients of the prize, and thanks Reinhard Genzel and the GRAVITY team for choosing our journal to present their spectacular results. A very nice summary of those results, presented by GRAVITY team member Guy Perrin at the 50th anniversary celebration of A&A, can be viewed on YouTube at