Astronomer Wins a Balzan Prize

At a ceremony on 7 November in Bern, Switzerland, the International Balzan Foundation is bestowing four Balzan Prizes, including one to Reinhard Genzel in the category of infrared astronomy. Every year, the foundation awards four Balzan Prizes, two in the sciences and two in the humanities, in various categories. Each prize is worth 1 million Swiss francs (about $715 000).

Genzel is being honored for his “fundamental contributions to infrared astronomy,” according to the citation, which adds that he “has developed instrumentation which enabled him and colleagues to make outstanding discoveries, including evidence for a massive black hole in the center of our galaxy.” (See Physics Today, February 2003, page 19 .) At the Max Planck Institute for Extraterrestrial Physics, based in Garching, Germany, Genzel directs the infrared and submillimeter astronomy group. Their principal research efforts involve investigating galactic nuclei and massive black holes, examining star formation and the dense interstellar medium, and aiming at a better understanding of how galaxies have formed and evolved. He also is a professor in the physics department at the University of California, Berkeley.

Genzel says his group has built instrumentation for studying with unprecedented spatial resolution the motions and orbits of stars in the core of the Milky Way. From those measurements, Genzel’s group could determine the gravitational potential of the core on scales of 10–20 light hours and show that the core contains a central mass concentration of 3 million solar masses. The data provide compelling evidence that this mass must be in the form of a massive black hole.

The group performed another experiment at the European Infrared Space Observatory. Genzel says their observations revealed “that the most luminous infrared bright galaxies in the local universe are powered by a fireworks of galactic star formation that followed the collision of two gas-rich galaxies. Those measurements give important clues about the starformation processes that probably dominated during the galaxy formation epoch 1–3 billion years after the Big Bang.”